gdb-9.2/gdb/dwarf2read.c

/* DWARF 2 debugging format support for GDB.

   Copyright (C) 1994-2020 Free Software Foundation, Inc.

   Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   Inc.  with support from Florida State University (under contract
   with the Ada Joint Program Office), and Silicon Graphics, Inc.
   Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   based on Fred Fish's (Cygnus Support) implementation of DWARF 1
   support.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* FIXME: Various die-reading functions need to be more careful with
   reading off the end of the section.
   E.g., load_partial_dies, read_partial_die.  */

#include "defs.h"
#include "dwarf2read.h"
#include "dwarf-index-cache.h"
#include "dwarf-index-common.h"
#include "bfd.h"
#include "elf-bfd.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "objfiles.h"
#include "dwarf2.h"
#include "buildsym.h"
#include "demangle.h"
#include "gdb-demangle.h"
#include "filenames.h"	/* for DOSish file names */
#include "macrotab.h"
#include "language.h"
#include "complaints.h"
#include "dwarf2expr.h"
#include "dwarf2loc.h"
#include "cp-support.h"
#include "hashtab.h"
#include "command.h"
#include "gdbcmd.h"
#include "block.h"
#include "addrmap.h"
#include "typeprint.h"
#include "psympriv.h"
#include "c-lang.h"
#include "go-lang.h"
#include "valprint.h"
#include "gdbcore.h" /* for gnutarget */
#include "gdb/gdb-index.h"
#include "gdb_bfd.h"
#include "f-lang.h"
#include "source.h"
#include "build-id.h"
#include "namespace.h"
#include "gdbsupport/function-view.h"
#include "gdbsupport/gdb_optional.h"
#include "gdbsupport/underlying.h"
#include "gdbsupport/hash_enum.h"
#include "filename-seen-cache.h"
#include "producer.h"
#include <fcntl.h>
#include <algorithm>
#include <unordered_map>
#include "gdbsupport/selftest.h"
#include "rust-lang.h"
#include "gdbsupport/pathstuff.h"

/* When == 1, print basic high level tracing messages.
   When > 1, be more verbose.
   This is in contrast to the low level DIE reading of dwarf_die_debug.  */
static unsigned int dwarf_read_debug = 0;

/* When non-zero, dump DIEs after they are read in.  */
static unsigned int dwarf_die_debug = 0;

/* When non-zero, dump line number entries as they are read in.  */
static unsigned int dwarf_line_debug = 0;

/* When true, cross-check physname against demangler.  */
static bool check_physname = false;

/* When true, do not reject deprecated .gdb_index sections.  */
static bool use_deprecated_index_sections = false;

static const struct objfile_key<dwarf2_per_objfile> dwarf2_objfile_data_key;

/* The "aclass" indices for various kinds of computed DWARF symbols.  */

static int dwarf2_locexpr_index;
static int dwarf2_loclist_index;
static int dwarf2_locexpr_block_index;
static int dwarf2_loclist_block_index;

/* Size of .debug_loclist section header for 32-bit DWARF format.  */
#define LOCLIST_HEADER_SIZE32 12;

/* Size of .debug_loclist section header for 64-bit DWARF format.  */
#define LOCLIST_HEADER_SIZE64 20;

/* An index into a (C++) symbol name component in a symbol name as
   recorded in the mapped_index's symbol table.  For each C++ symbol
   in the symbol table, we record one entry for the start of each
   component in the symbol in a table of name components, and then
   sort the table, in order to be able to binary search symbol names,
   ignoring leading namespaces, both completion and regular look up.
   For example, for symbol "A::B::C", we'll have an entry that points
   to "A::B::C", another that points to "B::C", and another for "C".
   Note that function symbols in GDB index have no parameter
   information, just the function/method names.  You can convert a
   name_component to a "const char *" using the
   'mapped_index::symbol_name_at(offset_type)' method.  */

struct name_component
{
  /* Offset in the symbol name where the component starts.  Stored as
     a (32-bit) offset instead of a pointer to save memory and improve
     locality on 64-bit architectures.  */
  offset_type name_offset;

  /* The symbol's index in the symbol and constant pool tables of a
     mapped_index.  */
  offset_type idx;
};

/* Base class containing bits shared by both .gdb_index and
   .debug_name indexes.  */

struct mapped_index_base
{
  mapped_index_base () = default;
  DISABLE_COPY_AND_ASSIGN (mapped_index_base);

  /* The name_component table (a sorted vector).  See name_component's
     description above.  */
  std::vector<name_component> name_components;

  /* How NAME_COMPONENTS is sorted.  */
  enum case_sensitivity name_components_casing;

  /* Return the number of names in the symbol table.  */
  virtual size_t symbol_name_count () const = 0;

  /* Get the name of the symbol at IDX in the symbol table.  */
  virtual const char *symbol_name_at (offset_type idx) const = 0;

  /* Return whether the name at IDX in the symbol table should be
     ignored.  */
  virtual bool symbol_name_slot_invalid (offset_type idx) const
  {
    return false;
  }

  /* Build the symbol name component sorted vector, if we haven't
     yet.  */
  void build_name_components ();

  /* Returns the lower (inclusive) and upper (exclusive) bounds of the
     possible matches for LN_NO_PARAMS in the name component
     vector.  */
  std::pair<std::vector<name_component>::const_iterator,
	    std::vector<name_component>::const_iterator>
    find_name_components_bounds (const lookup_name_info &ln_no_params,
				 enum language lang) const;

  /* Prevent deleting/destroying via a base class pointer.  */
protected:
  ~mapped_index_base() = default;
};

/* A description of the mapped index.  The file format is described in
   a comment by the code that writes the index.  */
struct mapped_index final : public mapped_index_base
{
  /* A slot/bucket in the symbol table hash.  */
  struct symbol_table_slot
  {
    const offset_type name;
    const offset_type vec;
  };

  /* Index data format version.  */
  int version = 0;

  /* The address table data.  */
  gdb::array_view<const gdb_byte> address_table;

  /* The symbol table, implemented as a hash table.  */
  gdb::array_view<symbol_table_slot> symbol_table;

  /* A pointer to the constant pool.  */
  const char *constant_pool = nullptr;

  bool symbol_name_slot_invalid (offset_type idx) const override
  {
    const auto &bucket = this->symbol_table[idx];
    return bucket.name == 0 && bucket.vec == 0;
  }

  /* Convenience method to get at the name of the symbol at IDX in the
     symbol table.  */
  const char *symbol_name_at (offset_type idx) const override
  { return this->constant_pool + MAYBE_SWAP (this->symbol_table[idx].name); }

  size_t symbol_name_count () const override
  { return this->symbol_table.size (); }
};

/* A description of the mapped .debug_names.
   Uninitialized map has CU_COUNT 0.  */
struct mapped_debug_names final : public mapped_index_base
{
  mapped_debug_names (struct dwarf2_per_objfile *dwarf2_per_objfile_)
  : dwarf2_per_objfile (dwarf2_per_objfile_)
  {}

  struct dwarf2_per_objfile *dwarf2_per_objfile;
  bfd_endian dwarf5_byte_order;
  bool dwarf5_is_dwarf64;
  bool augmentation_is_gdb;
  uint8_t offset_size;
  uint32_t cu_count = 0;
  uint32_t tu_count, bucket_count, name_count;
  const gdb_byte *cu_table_reordered, *tu_table_reordered;
  const uint32_t *bucket_table_reordered, *hash_table_reordered;
  const gdb_byte *name_table_string_offs_reordered;
  const gdb_byte *name_table_entry_offs_reordered;
  const gdb_byte *entry_pool;

  struct index_val
  {
    ULONGEST dwarf_tag;
    struct attr
    {
      /* Attribute name DW_IDX_*.  */
      ULONGEST dw_idx;

      /* Attribute form DW_FORM_*.  */
      ULONGEST form;

      /* Value if FORM is DW_FORM_implicit_const.  */
      LONGEST implicit_const;
    };
    std::vector<attr> attr_vec;
  };

  std::unordered_map<ULONGEST, index_val> abbrev_map;

  const char *namei_to_name (uint32_t namei) const;

  /* Implementation of the mapped_index_base virtual interface, for
     the name_components cache.  */

  const char *symbol_name_at (offset_type idx) const override
  { return namei_to_name (idx); }

  size_t symbol_name_count () const override
  { return this->name_count; }
};

/* See dwarf2read.h.  */

dwarf2_per_objfile *
get_dwarf2_per_objfile (struct objfile *objfile)
{
  return dwarf2_objfile_data_key.get (objfile);
}

/* Default names of the debugging sections.  */

/* Note that if the debugging section has been compressed, it might
   have a name like .zdebug_info.  */

static const struct dwarf2_debug_sections dwarf2_elf_names =
{
  { ".debug_info", ".zdebug_info" },
  { ".debug_abbrev", ".zdebug_abbrev" },
  { ".debug_line", ".zdebug_line" },
  { ".debug_loc", ".zdebug_loc" },
  { ".debug_loclists", ".zdebug_loclists" },
  { ".debug_macinfo", ".zdebug_macinfo" },
  { ".debug_macro", ".zdebug_macro" },
  { ".debug_str", ".zdebug_str" },
  { ".debug_str_offsets", ".zdebug_str_offsets" },
  { ".debug_line_str", ".zdebug_line_str" },
  { ".debug_ranges", ".zdebug_ranges" },
  { ".debug_rnglists", ".zdebug_rnglists" },
  { ".debug_types", ".zdebug_types" },
  { ".debug_addr", ".zdebug_addr" },
  { ".debug_frame", ".zdebug_frame" },
  { ".eh_frame", NULL },
  { ".gdb_index", ".zgdb_index" },
  { ".debug_names", ".zdebug_names" },
  { ".debug_aranges", ".zdebug_aranges" },
  23
};

/* List of DWO/DWP sections.  */

static const struct dwop_section_names
{
  struct dwarf2_section_names abbrev_dwo;
  struct dwarf2_section_names info_dwo;
  struct dwarf2_section_names line_dwo;
  struct dwarf2_section_names loc_dwo;
  struct dwarf2_section_names loclists_dwo;
  struct dwarf2_section_names macinfo_dwo;
  struct dwarf2_section_names macro_dwo;
  struct dwarf2_section_names rnglists_dwo;
  struct dwarf2_section_names str_dwo;
  struct dwarf2_section_names str_offsets_dwo;
  struct dwarf2_section_names types_dwo;
  struct dwarf2_section_names cu_index;
  struct dwarf2_section_names tu_index;
}
dwop_section_names =
{
  { ".debug_abbrev.dwo", ".zdebug_abbrev.dwo" },
  { ".debug_info.dwo", ".zdebug_info.dwo" },
  { ".debug_line.dwo", ".zdebug_line.dwo" },
  { ".debug_loc.dwo", ".zdebug_loc.dwo" },
  { ".debug_loclists.dwo", ".zdebug_loclists.dwo" },
  { ".debug_macinfo.dwo", ".zdebug_macinfo.dwo" },
  { ".debug_macro.dwo", ".zdebug_macro.dwo" },
  { ".debug_rnglists.dwo", ".zdebug_rnglists.dwo" },
  { ".debug_str.dwo", ".zdebug_str.dwo" },
  { ".debug_str_offsets.dwo", ".zdebug_str_offsets.dwo" },
  { ".debug_types.dwo", ".zdebug_types.dwo" },
  { ".debug_cu_index", ".zdebug_cu_index" },
  { ".debug_tu_index", ".zdebug_tu_index" },
};

/* local data types */

/* The data in a compilation unit header, after target2host
   translation, looks like this.  */
struct comp_unit_head
{
  unsigned int length;
  short version;
  unsigned char addr_size;
  unsigned char signed_addr_p;
  sect_offset abbrev_sect_off;

  /* Size of file offsets; either 4 or 8.  */
  unsigned int offset_size;

  /* Size of the length field; either 4 or 12.  */
  unsigned int initial_length_size;

  enum dwarf_unit_type unit_type;

  /* Offset to the first byte of this compilation unit header in the
     .debug_info section, for resolving relative reference dies.  */
  sect_offset sect_off;

  /* Offset to first die in this cu from the start of the cu.
     This will be the first byte following the compilation unit header.  */
  cu_offset first_die_cu_offset;


  /* 64-bit signature of this unit. For type units, it denotes the signature of
     the type (DW_UT_type in DWARF 4, additionally DW_UT_split_type in DWARF 5).
     Also used in DWARF 5, to denote the dwo id when the unit type is
     DW_UT_skeleton or DW_UT_split_compile.  */
  ULONGEST signature;

  /* For types, offset in the type's DIE of the type defined by this TU.  */
  cu_offset type_cu_offset_in_tu;
};

/* Type used for delaying computation of method physnames.
   See comments for compute_delayed_physnames.  */
struct delayed_method_info
{
  /* The type to which the method is attached, i.e., its parent class.  */
  struct type *type;

  /* The index of the method in the type's function fieldlists.  */
  int fnfield_index;

  /* The index of the method in the fieldlist.  */
  int index;

  /* The name of the DIE.  */
  const char *name;

  /*  The DIE associated with this method.  */
  struct die_info *die;
};

/* The location list and range list section (.debug_loclist) begins with a
   header, which contains the following information.  */
struct loclist_header
{
  /* A 4-byte or 12-byte length containing the length of the
     set of entries for this compilation unit, not including the
     length field itself.  */
  unsigned int length;

  /* A 2-byte version identifier.  */
  short version;

  /* A 1-byte unsigned integer containing the size in bytes of an address on
     the target system.  */
  unsigned char addr_size;

/* A 1-byte unsigned integer containing the size in bytes of a segment selector
   on the target system.  */
  unsigned char segment_collector_size;

  /* A 4-byte count of the number of offsets that follow the header.  */
  unsigned int offset_entry_count;
};

/* Internal state when decoding a particular compilation unit.  */
struct dwarf2_cu
{
  explicit dwarf2_cu (struct dwarf2_per_cu_data *per_cu);
  ~dwarf2_cu ();

  DISABLE_COPY_AND_ASSIGN (dwarf2_cu);

  /* TU version of handle_DW_AT_stmt_list for read_type_unit_scope.
     Create the set of symtabs used by this TU, or if this TU is sharing
     symtabs with another TU and the symtabs have already been created
     then restore those symtabs in the line header.
     We don't need the pc/line-number mapping for type units.  */
  void setup_type_unit_groups (struct die_info *die);

  /* Start a symtab for DWARF.  NAME, COMP_DIR, LOW_PC are passed to the
     buildsym_compunit constructor.  */
  struct compunit_symtab *start_symtab (const char *name,
					const char *comp_dir,
					CORE_ADDR low_pc);

  /* Reset the builder.  */
  void reset_builder () { m_builder.reset (); }

  /* The header of the compilation unit.  */
  struct comp_unit_head header {};

  /* Base address of this compilation unit.  */
  CORE_ADDR base_address = 0;

  /* Non-zero if base_address has been set.  */
  int base_known = 0;

  /* CU rnglist ranges came from skeleton unit. */
  int cu_ranges_from_skeleton = 0;

  /* The language we are debugging.  */
  enum language language = language_unknown;
  const struct language_defn *language_defn = nullptr;

  const char *producer = nullptr;

private:
  /* The symtab builder for this CU.  This is only non-NULL when full
     symbols are being read.  */
  std::unique_ptr<buildsym_compunit> m_builder;

public:
  /* The generic symbol table building routines have separate lists for
     file scope symbols and all all other scopes (local scopes).  So
     we need to select the right one to pass to add_symbol_to_list().
     We do it by keeping a pointer to the correct list in list_in_scope.

     FIXME: The original dwarf code just treated the file scope as the
     first local scope, and all other local scopes as nested local
     scopes, and worked fine.  Check to see if we really need to
     distinguish these in buildsym.c.  */
  struct pending **list_in_scope = nullptr;

  /* Hash table holding all the loaded partial DIEs
     with partial_die->offset.SECT_OFF as hash.  */
  htab_t partial_dies = nullptr;

  /* Storage for things with the same lifetime as this read-in compilation
     unit, including partial DIEs.  */
  auto_obstack comp_unit_obstack;

  /* When multiple dwarf2_cu structures are living in memory, this field
     chains them all together, so that they can be released efficiently.
     We will probably also want a generation counter so that most-recently-used
     compilation units are cached...  */
  struct dwarf2_per_cu_data *read_in_chain = nullptr;

  /* Backlink to our per_cu entry.  */
  struct dwarf2_per_cu_data *per_cu;

  /* How many compilation units ago was this CU last referenced?  */
  int last_used = 0;

  /* A hash table of DIE cu_offset for following references with
     die_info->offset.sect_off as hash.  */
  htab_t die_hash = nullptr;

  /* Full DIEs if read in.  */
  struct die_info *dies = nullptr;

  /* A set of pointers to dwarf2_per_cu_data objects for compilation
     units referenced by this one.  Only set during full symbol processing;
     partial symbol tables do not have dependencies.  */
  htab_t dependencies = nullptr;

  /* Header data from the line table, during full symbol processing.  */
  struct line_header *line_header = nullptr;
  /* Non-NULL if LINE_HEADER is owned by this DWARF_CU.  Otherwise,
     it's owned by dwarf2_per_objfile::line_header_hash.  If non-NULL,
     this is the DW_TAG_compile_unit die for this CU.  We'll hold on
     to the line header as long as this DIE is being processed.  See
     process_die_scope.  */
  die_info *line_header_die_owner = nullptr;

  /* A list of methods which need to have physnames computed
     after all type information has been read.  */
  std::vector<delayed_method_info> method_list;

  /* To be copied to symtab->call_site_htab.  */
  htab_t call_site_htab = nullptr;

  /* Non-NULL if this CU came from a DWO file.
     There is an invariant here that is important to remember:
     Except for attributes copied from the top level DIE in the "main"
     (or "stub") file in preparation for reading the DWO file
     (e.g., DW_AT_addr_base), we KISS: there is only *one* CU.
     Either there isn't a DWO file (in which case this is NULL and the point
     is moot), or there is and either we're not going to read it (in which
     case this is NULL) or there is and we are reading it (in which case this
     is non-NULL).  */
  struct dwo_unit *dwo_unit = nullptr;

  /* The DW_AT_addr_base (DW_AT_GNU_addr_base) attribute if present.
     Note this value comes from the Fission stub CU/TU's DIE.  */
  gdb::optional<ULONGEST> addr_base;

  /* The DW_AT_rnglists_base attribute if present.
     Note this value comes from the Fission stub CU/TU's DIE.
     Also note that the value is zero in the non-DWO case so this value can
     be used without needing to know whether DWO files are in use or not.
     N.B. This does not apply to DW_AT_ranges appearing in
     DW_TAG_compile_unit dies.  This is a bit of a wart, consider if ever
     DW_AT_ranges appeared in the DW_TAG_compile_unit of DWO DIEs: then
     DW_AT_rnglists_base *would* have to be applied, and we'd have to care
     whether the DW_AT_ranges attribute came from the skeleton or DWO.  */
  ULONGEST ranges_base = 0;

  /* The DW_AT_loclistss_base attribute if present.  */
  gdb::optional<ULONGEST> loclist_base;

  /* When reading debug info generated by older versions of rustc, we
     have to rewrite some union types to be struct types with a
     variant part.  This rewriting must be done after the CU is fully
     read in, because otherwise at the point of rewriting some struct
     type might not have been fully processed.  So, we keep a list of
     all such types here and process them after expansion.  */
  std::vector<struct type *> rust_unions;

  /* The DW_AT_str_offsets_base attribute if present.  For DWARF 4 version DWO
     files, the value is implicitly zero.  For DWARF 5 version DWO files, the
     value is often implicit and is the size of the header of
     .debug_str_offsets section (8 or 4, depending on the address size).  */
  gdb::optional<ULONGEST> str_offsets_base;

  /* Mark used when releasing cached dies.  */
  bool mark : 1;

  /* This CU references .debug_loc.  See the symtab->locations_valid field.
     This test is imperfect as there may exist optimized debug code not using
     any location list and still facing inlining issues if handled as
     unoptimized code.  For a future better test see GCC PR other/32998.  */
  bool has_loclist : 1;

  /* These cache the results for producer_is_* fields.  CHECKED_PRODUCER is true
     if all the producer_is_* fields are valid.  This information is cached
     because profiling CU expansion showed excessive time spent in
     producer_is_gxx_lt_4_6.  */
  bool checked_producer : 1;
  bool producer_is_gxx_lt_4_6 : 1;
  bool producer_is_gcc_lt_4_3 : 1;
  bool producer_is_icc : 1;
  bool producer_is_icc_lt_14 : 1;
  bool producer_is_codewarrior : 1;

  /* When true, the file that we're processing is known to have
     debugging info for C++ namespaces.  GCC 3.3.x did not produce
     this information, but later versions do.  */

  bool processing_has_namespace_info : 1;

  struct partial_die_info *find_partial_die (sect_offset sect_off);

  /* If this CU was inherited by another CU (via specification,
     abstract_origin, etc), this is the ancestor CU.  */
  dwarf2_cu *ancestor;

  /* Get the buildsym_compunit for this CU.  */
  buildsym_compunit *get_builder ()
  {
    /* If this CU has a builder associated with it, use that.  */
    if (m_builder != nullptr)
      return m_builder.get ();

    /* Otherwise, search ancestors for a valid builder.  */
    if (ancestor != nullptr)
      return ancestor->get_builder ();

    return nullptr;
  }
};

/* A struct that can be used as a hash key for tables based on DW_AT_stmt_list.
   This includes type_unit_group and quick_file_names.  */

struct stmt_list_hash
{
  /* The DWO unit this table is from or NULL if there is none.  */
  struct dwo_unit *dwo_unit;

  /* Offset in .debug_line or .debug_line.dwo.  */
  sect_offset line_sect_off;
};

/* Each element of dwarf2_per_objfile->type_unit_groups is a pointer to
   an object of this type.  */

struct type_unit_group
{
  /* dwarf2read.c's main "handle" on a TU symtab.
     To simplify things we create an artificial CU that "includes" all the
     type units using this stmt_list so that the rest of the code still has
     a "per_cu" handle on the symtab.
     This PER_CU is recognized by having no section.  */
#define IS_TYPE_UNIT_GROUP(per_cu) ((per_cu)->section == NULL)
  struct dwarf2_per_cu_data per_cu;

  /* The TUs that share this DW_AT_stmt_list entry.
     This is added to while parsing type units to build partial symtabs,
     and is deleted afterwards and not used again.  */
  std::vector<signatured_type *> *tus;

  /* The compunit symtab.
     Type units in a group needn't all be defined in the same source file,
     so we create an essentially anonymous symtab as the compunit symtab.  */
  struct compunit_symtab *compunit_symtab;

  /* The data used to construct the hash key.  */
  struct stmt_list_hash hash;

  /* The number of symtabs from the line header.
     The value here must match line_header.num_file_names.  */
  unsigned int num_symtabs;

  /* The symbol tables for this TU (obtained from the files listed in
     DW_AT_stmt_list).
     WARNING: The order of entries here must match the order of entries
     in the line header.  After the first TU using this type_unit_group, the
     line header for the subsequent TUs is recreated from this.  This is done
     because we need to use the same symtabs for each TU using the same
     DW_AT_stmt_list value.  Also note that symtabs may be repeated here,
     there's no guarantee the line header doesn't have duplicate entries.  */
  struct symtab **symtabs;
};

/* These sections are what may appear in a (real or virtual) DWO file.  */

struct dwo_sections
{
  struct dwarf2_section_info abbrev;
  struct dwarf2_section_info line;
  struct dwarf2_section_info loc;
  struct dwarf2_section_info loclists;
  struct dwarf2_section_info macinfo;
  struct dwarf2_section_info macro;
  struct dwarf2_section_info rnglists;
  struct dwarf2_section_info str;
  struct dwarf2_section_info str_offsets;
  /* In the case of a virtual DWO file, these two are unused.  */
  struct dwarf2_section_info info;
  std::vector<dwarf2_section_info> types;
};

/* CUs/TUs in DWP/DWO files.  */

struct dwo_unit
{
  /* Backlink to the containing struct dwo_file.  */
  struct dwo_file *dwo_file;

  /* The "id" that distinguishes this CU/TU.
     .debug_info calls this "dwo_id", .debug_types calls this "signature".
     Since signatures came first, we stick with it for consistency.  */
  ULONGEST signature;

  /* The section this CU/TU lives in, in the DWO file.  */
  struct dwarf2_section_info *section;

  /* Same as dwarf2_per_cu_data:{sect_off,length} but in the DWO section.  */
  sect_offset sect_off;
  unsigned int length;

  /* For types, offset in the type's DIE of the type defined by this TU.  */
  cu_offset type_offset_in_tu;
};

/* include/dwarf2.h defines the DWP section codes.
   It defines a max value but it doesn't define a min value, which we
   use for error checking, so provide one.  */

enum dwp_v2_section_ids
{
  DW_SECT_MIN = 1
};

/* Data for one DWO file.

   This includes virtual DWO files (a virtual DWO file is a DWO file as it
   appears in a DWP file).  DWP files don't really have DWO files per se -
   comdat folding of types "loses" the DWO file they came from, and from
   a high level view DWP files appear to contain a mass of random types.
   However, to maintain consistency with the non-DWP case we pretend DWP
   files contain virtual DWO files, and we assign each TU with one virtual
   DWO file (generally based on the line and abbrev section offsets -
   a heuristic that seems to work in practice).  */

struct dwo_file
{
  dwo_file () = default;
  DISABLE_COPY_AND_ASSIGN (dwo_file);

  /* The DW_AT_GNU_dwo_name or DW_AT_dwo_name attribute.
     For virtual DWO files the name is constructed from the section offsets
     of abbrev,line,loc,str_offsets so that we combine virtual DWO files
     from related CU+TUs.  */
  const char *dwo_name = nullptr;

  /* The DW_AT_comp_dir attribute.  */
  const char *comp_dir = nullptr;

  /* The bfd, when the file is open.  Otherwise this is NULL.
     This is unused(NULL) for virtual DWO files where we use dwp_file.dbfd.  */
  gdb_bfd_ref_ptr dbfd;

  /* The sections that make up this DWO file.
     Remember that for virtual DWO files in DWP V2 or DWP V5, these are virtual
     sections (for lack of a better name).  */
  struct dwo_sections sections {};

  /* The CUs in the file.
     Each element is a struct dwo_unit. Multiple CUs per DWO are supported as
     an extension to handle LLVM's Link Time Optimization output (where
     multiple source files may be compiled into a single object/dwo pair). */
  htab_t cus {};

  /* Table of TUs in the file.
     Each element is a struct dwo_unit.  */
  htab_t tus {};
};

/* These sections are what may appear in a DWP file.  */

struct dwp_sections
{
  /* These are used by DWP versions 1, 2 and 5.  */
  struct dwarf2_section_info str;
  struct dwarf2_section_info cu_index;
  struct dwarf2_section_info tu_index;

  /* These are only used by DWP version 2 and version 5 files.
     In DWP version 1 the .debug_info.dwo, .debug_types.dwo, and other
     sections are referenced by section number, and are not recorded here.
     In DWP version 2 there is at most one copy of all these sections, each
     section being (effectively) comprised of the concatenation of all of the
     individual sections that exist in the version 1 format.
     To keep the code simple we treat each of these concatenated pieces as a
     section itself (a virtual section?).  */
  struct dwarf2_section_info abbrev;
  struct dwarf2_section_info info;
  struct dwarf2_section_info line;
  struct dwarf2_section_info loc;
  struct dwarf2_section_info loclists;
  struct dwarf2_section_info macinfo;
  struct dwarf2_section_info macro;
  struct dwarf2_section_info rnglists;
  struct dwarf2_section_info str_offsets;
  struct dwarf2_section_info types;
};

/* These sections are what may appear in a virtual DWO file in DWP version 1.
   A virtual DWO file is a DWO file as it appears in a DWP file.  */

struct virtual_v1_dwo_sections
{
  struct dwarf2_section_info abbrev;
  struct dwarf2_section_info line;
  struct dwarf2_section_info loc;
  struct dwarf2_section_info macinfo;
  struct dwarf2_section_info macro;
  struct dwarf2_section_info str_offsets;
  /* Each DWP hash table entry records one CU or one TU.
     That is recorded here, and copied to dwo_unit.section.  */
  struct dwarf2_section_info info_or_types;
};

/* Similar to virtual_v1_dwo_sections, but for DWP version 2 or 5.
   In version 2, the sections of the DWO files are concatenated together
   and stored in one section of that name.  Thus each ELF section contains
   several "virtual" sections.  */

struct virtual_v2_dwo_sections
{
  bfd_size_type abbrev_offset;
  bfd_size_type abbrev_size;

  bfd_size_type line_offset;
  bfd_size_type line_size;

  bfd_size_type loc_offset;
  bfd_size_type loc_size;

  bfd_size_type loclists_offset;
  bfd_size_type loclists_size;

  bfd_size_type macinfo_offset;
  bfd_size_type macinfo_size;

  bfd_size_type macro_offset;
  bfd_size_type macro_size;

  bfd_size_type rnglists_offset;
  bfd_size_type rnglists_size;

  bfd_size_type str_offsets_offset;
  bfd_size_type str_offsets_size;

  /* Each DWP hash table entry records one CU or one TU.
     That is recorded here, and copied to dwo_unit.section.  */
  bfd_size_type info_or_types_offset;
  bfd_size_type info_or_types_size;
};

/* Contents of DWP hash tables.  */

struct dwp_hash_table
{
  uint32_t version, nr_columns;
  uint32_t nr_units, nr_slots;
  const gdb_byte *hash_table, *unit_table;
  union
  {
    struct
    {
      const gdb_byte *indices;
    } v1;
    struct
    {
      /* This is indexed by column number and gives the id of the section
	 in that column.  */
#define MAX_NR_V2_DWO_SECTIONS \
  (1 /* .debug_info or .debug_types */ \
   + 1 /* .debug_abbrev */ \
   + 1 /* .debug_line */ \
   + 1 /* .debug_loc */ \
   + 1 /* .debug_str_offsets */ \
   + 1 /* .debug_macro or .debug_macinfo */)
      int section_ids[MAX_NR_V2_DWO_SECTIONS];
      const gdb_byte *offsets;
      const gdb_byte *sizes;
    } v2;
    struct
    {
#define MAX_NR_V5_DWO_SECTIONS \
  (1 /* .debug_info or .debug_types */ \
   + 1 /* .debug_abbrev */ \
   + 1 /* .debug_line */ \
   + 1 /* .debug_loclists */ \
   + 1 /* .debug_str_offsets */ \
   + 1 /* .debug_macro */ \
   + 1 /* .debug_rnglists */)
      int section_ids[MAX_NR_V5_DWO_SECTIONS];
      const gdb_byte *offsets;
      const gdb_byte *sizes;
    } v5;
  } section_pool;
};

/* Data for one DWP file.  */

struct dwp_file
{
  dwp_file (const char *name_, gdb_bfd_ref_ptr &&abfd)
    : name (name_),
      dbfd (std::move (abfd))
  {
  }

  /* Name of the file.  */
  const char *name;

  /* File format version.  */
  int version = 0;

  /* The bfd.  */
  gdb_bfd_ref_ptr dbfd;

  /* Section info for this file.  */
  struct dwp_sections sections {};

  /* Table of CUs in the file.  */
  const struct dwp_hash_table *cus = nullptr;

  /* Table of TUs in the file.  */
  const struct dwp_hash_table *tus = nullptr;

  /* Tables of loaded CUs/TUs.  Each entry is a struct dwo_unit *.  */
  htab_t loaded_cus {};
  htab_t loaded_tus {};

  /* Table to map ELF section numbers to their sections.
     This is only needed for the DWP V1 file format.  */
  unsigned int num_sections = 0;
  asection **elf_sections = nullptr;
};

/* Struct used to pass misc. parameters to read_die_and_children, et
   al.  which are used for both .debug_info and .debug_types dies.
   All parameters here are unchanging for the life of the call.  This
   struct exists to abstract away the constant parameters of die reading.  */

struct die_reader_specs
{
  /* The bfd of die_section.  */
  bfd* abfd;

  /* The CU of the DIE we are parsing.  */
  struct dwarf2_cu *cu;

  /* Non-NULL if reading a DWO file (including one packaged into a DWP).  */
  struct dwo_file *dwo_file;

  /* The section the die comes from.
     This is either .debug_info or .debug_types, or the .dwo variants.  */
  struct dwarf2_section_info *die_section;

  /* die_section->buffer.  */
  const gdb_byte *buffer;

  /* The end of the buffer.  */
  const gdb_byte *buffer_end;

  /* The value of the DW_AT_comp_dir attribute.  */
  const char *comp_dir;

  /* The abbreviation table to use when reading the DIEs.  */
  struct abbrev_table *abbrev_table;
};

/* Type of function passed to init_cutu_and_read_dies, et.al.  */
typedef void (die_reader_func_ftype) (const struct die_reader_specs *reader,
				      const gdb_byte *info_ptr,
				      struct die_info *comp_unit_die,
				      int has_children,
				      void *data);

/* dir_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5 and
   later.  */
typedef int dir_index;

/* file_name_index is 1-based in DWARF 4 and before, and is 0-based in DWARF 5
   and later.  */
typedef int file_name_index;

struct file_entry
{
  file_entry () = default;

  file_entry (const char *name_, dir_index d_index_,
	      unsigned int mod_time_, unsigned int length_)
    : name (name_),
      d_index (d_index_),
      mod_time (mod_time_),
      length (length_)
  {}

  /* Return the include directory at D_INDEX stored in LH.  Returns
     NULL if D_INDEX is out of bounds.  */
  const char *include_dir (const line_header *lh) const;

  /* The file name.  Note this is an observing pointer.  The memory is
     owned by debug_line_buffer.  */
  const char *name {};

  /* The directory index (1-based).  */
  dir_index d_index {};

  unsigned int mod_time {};

  unsigned int length {};

  /* True if referenced by the Line Number Program.  */
  bool included_p {};

  /* The associated symbol table, if any.  */
  struct symtab *symtab {};
};

/* The line number information for a compilation unit (found in the
   .debug_line section) begins with a "statement program header",
   which contains the following information.  */
struct line_header
{
  line_header ()
    : offset_in_dwz {}
  {}

  /* Add an entry to the include directory table.  */
  void add_include_dir (const char *include_dir);

  /* Add an entry to the file name table.  */
  void add_file_name (const char *name, dir_index d_index,
		      unsigned int mod_time, unsigned int length);

  /* Return the include dir at INDEX (0-based in DWARF 5 and 1-based before).
     Returns NULL if INDEX is out of bounds.  */
  const char *include_dir_at (dir_index index) const
  {
    int vec_index;
    if (version >= 5)
      vec_index = index;
    else
      vec_index = index - 1;
    if (vec_index < 0 || vec_index >= m_include_dirs.size ())
      return NULL;
    return m_include_dirs[vec_index];
  }

  bool is_valid_file_index (int file_index)
  {
    if (version >= 5)
      return 0 <= file_index && file_index < file_names_size ();
    return 1 <= file_index && file_index <= file_names_size ();
  }

  /* Return the file name at INDEX (0-based in DWARF 5 and 1-based before).
     Returns NULL if INDEX is out of bounds.  */
  file_entry *file_name_at (file_name_index index)
  {
    int vec_index;
    if (version >= 5)
      vec_index = index;
    else
      vec_index = index - 1;
    if (vec_index < 0 || vec_index >= m_file_names.size ())
      return NULL;
    return &m_file_names[vec_index];
  }

  /* The indexes are 0-based in DWARF 5 and 1-based in DWARF 4. Therefore,
     this method should only be used to iterate through all file entries in an
     index-agnostic manner.  */
  std::vector<file_entry> &file_names ()
  { return m_file_names; }

  /* Offset of line number information in .debug_line section.  */
  sect_offset sect_off {};

  /* OFFSET is for struct dwz_file associated with dwarf2_per_objfile.  */
  unsigned offset_in_dwz : 1; /* Can't initialize bitfields in-class.  */

  unsigned int total_length {};
  unsigned short version {};
  unsigned int header_length {};
  unsigned char minimum_instruction_length {};
  unsigned char maximum_ops_per_instruction {};
  unsigned char default_is_stmt {};
  int line_base {};
  unsigned char line_range {};
  unsigned char opcode_base {};

  /* standard_opcode_lengths[i] is the number of operands for the
     standard opcode whose value is i.  This means that
     standard_opcode_lengths[0] is unused, and the last meaningful
     element is standard_opcode_lengths[opcode_base - 1].  */
  std::unique_ptr<unsigned char[]> standard_opcode_lengths;

  int file_names_size ()
  { return m_file_names.size(); }

  /* The start and end of the statement program following this
     header.  These point into dwarf2_per_objfile->line_buffer.  */
  const gdb_byte *statement_program_start {}, *statement_program_end {};

 private:
  /* The include_directories table.  Note these are observing
     pointers.  The memory is owned by debug_line_buffer.  */
  std::vector<const char *> m_include_dirs;

  /* The file_names table. This is private because the meaning of indexes
     differs among DWARF versions (The first valid index is 1 in DWARF 4 and
     before, and is 0 in DWARF 5 and later).  So the client should use
     file_name_at method for access.  */
  std::vector<file_entry> m_file_names;
};

typedef std::unique_ptr<line_header> line_header_up;

const char *
file_entry::include_dir (const line_header *lh) const
{
  return lh->include_dir_at (d_index);
}

/* When we construct a partial symbol table entry we only
   need this much information.  */
struct partial_die_info : public allocate_on_obstack
  {
    partial_die_info (sect_offset sect_off, struct abbrev_info *abbrev);

    /* Disable assign but still keep copy ctor, which is needed
       load_partial_dies.   */
    partial_die_info& operator=(const partial_die_info& rhs) = delete;

    /* Adjust the partial die before generating a symbol for it.  This
       function may set the is_external flag or change the DIE's
       name.  */
    void fixup (struct dwarf2_cu *cu);

    /* Read a minimal amount of information into the minimal die
       structure.  */
    const gdb_byte *read (const struct die_reader_specs *reader,
			  const struct abbrev_info &abbrev,
			  const gdb_byte *info_ptr);

    /* Offset of this DIE.  */
    const sect_offset sect_off;

    /* DWARF-2 tag for this DIE.  */
    const ENUM_BITFIELD(dwarf_tag) tag : 16;

    /* Assorted flags describing the data found in this DIE.  */
    const unsigned int has_children : 1;

    unsigned int is_external : 1;
    unsigned int is_declaration : 1;
    unsigned int has_type : 1;
    unsigned int has_specification : 1;
    unsigned int has_pc_info : 1;
    unsigned int may_be_inlined : 1;

    /* This DIE has been marked DW_AT_main_subprogram.  */
    unsigned int main_subprogram : 1;

    /* Flag set if the SCOPE field of this structure has been
       computed.  */
    unsigned int scope_set : 1;

    /* Flag set if the DIE has a byte_size attribute.  */
    unsigned int has_byte_size : 1;

    /* Flag set if the DIE has a DW_AT_const_value attribute.  */
    unsigned int has_const_value : 1;

    /* Flag set if any of the DIE's children are template arguments.  */
    unsigned int has_template_arguments : 1;

    /* Flag set if fixup has been called on this die.  */
    unsigned int fixup_called : 1;

    /* Flag set if DW_TAG_imported_unit uses DW_FORM_GNU_ref_alt.  */
    unsigned int is_dwz : 1;

    /* Flag set if spec_offset uses DW_FORM_GNU_ref_alt.  */
    unsigned int spec_is_dwz : 1;

    /* The name of this DIE.  Normally the value of DW_AT_name, but
       sometimes a default name for unnamed DIEs.  */
    const char *name = nullptr;

    /* The linkage name, if present.  */
    const char *linkage_name = nullptr;

    /* The scope to prepend to our children.  This is generally
       allocated on the comp_unit_obstack, so will disappear
       when this compilation unit leaves the cache.  */
    const char *scope = nullptr;

    /* Some data associated with the partial DIE.  The tag determines
       which field is live.  */
    union
    {
      /* The location description associated with this DIE, if any.  */
      struct dwarf_block *locdesc;
      /* The offset of an import, for DW_TAG_imported_unit.  */
      sect_offset sect_off;
    } d {};

    /* If HAS_PC_INFO, the PC range associated with this DIE.  */
    CORE_ADDR lowpc = 0;
    CORE_ADDR highpc = 0;

    /* Pointer into the info_buffer (or types_buffer) pointing at the target of
       DW_AT_sibling, if any.  */
    /* NOTE: This member isn't strictly necessary, partial_die_info::read
       could return DW_AT_sibling values to its caller load_partial_dies.  */
    const gdb_byte *sibling = nullptr;

    /* If HAS_SPECIFICATION, the offset of the DIE referred to by
       DW_AT_specification (or DW_AT_abstract_origin or
       DW_AT_extension).  */
    sect_offset spec_offset {};

    /* Pointers to this DIE's parent, first child, and next sibling,
       if any.  */
    struct partial_die_info *die_parent = nullptr;
    struct partial_die_info *die_child = nullptr;
    struct partial_die_info *die_sibling = nullptr;

    friend struct partial_die_info *
    dwarf2_cu::find_partial_die (sect_offset sect_off);

  private:
    /* Only need to do look up in dwarf2_cu::find_partial_die.  */
    partial_die_info (sect_offset sect_off)
      : partial_die_info (sect_off, DW_TAG_padding, 0)
    {
    }

    partial_die_info (sect_offset sect_off_, enum dwarf_tag tag_,
		      int has_children_)
      : sect_off (sect_off_), tag (tag_), has_children (has_children_)
    {
      is_external = 0;
      is_declaration = 0;
      has_type = 0;
      has_specification = 0;
      has_pc_info = 0;
      may_be_inlined = 0;
      main_subprogram = 0;
      scope_set = 0;
      has_byte_size = 0;
      has_const_value = 0;
      has_template_arguments = 0;
      fixup_called = 0;
      is_dwz = 0;
      spec_is_dwz = 0;
    }
  };

/* This data structure holds the information of an abbrev.  */
struct abbrev_info
  {
    unsigned int number;	/* number identifying abbrev */
    enum dwarf_tag tag;		/* dwarf tag */
    unsigned short has_children;		/* boolean */
    unsigned short num_attrs;	/* number of attributes */
    struct attr_abbrev *attrs;	/* an array of attribute descriptions */
    struct abbrev_info *next;	/* next in chain */
  };

struct attr_abbrev
  {
    ENUM_BITFIELD(dwarf_attribute) name : 16;
    ENUM_BITFIELD(dwarf_form) form : 16;

    /* It is valid only if FORM is DW_FORM_implicit_const.  */
    LONGEST implicit_const;
  };

/* Size of abbrev_table.abbrev_hash_table.  */
#define ABBREV_HASH_SIZE 121

/* Top level data structure to contain an abbreviation table.  */

struct abbrev_table
{
  explicit abbrev_table (sect_offset off)
    : sect_off (off)
  {
    m_abbrevs =
      XOBNEWVEC (&abbrev_obstack, struct abbrev_info *, ABBREV_HASH_SIZE);
    memset (m_abbrevs, 0, ABBREV_HASH_SIZE * sizeof (struct abbrev_info *));
  }

  DISABLE_COPY_AND_ASSIGN (abbrev_table);

  /* Allocate space for a struct abbrev_info object in
     ABBREV_TABLE.  */
  struct abbrev_info *alloc_abbrev ();

  /* Add an abbreviation to the table.  */
  void add_abbrev (unsigned int abbrev_number, struct abbrev_info *abbrev);

  /* Look up an abbrev in the table.
     Returns NULL if the abbrev is not found.  */

  struct abbrev_info *lookup_abbrev (unsigned int abbrev_number);


  /* Where the abbrev table came from.
     This is used as a sanity check when the table is used.  */
  const sect_offset sect_off;

  /* Storage for the abbrev table.  */
  auto_obstack abbrev_obstack;

private:

  /* Hash table of abbrevs.
     This is an array of size ABBREV_HASH_SIZE allocated in abbrev_obstack.
     It could be statically allocated, but the previous code didn't so we
     don't either.  */
  struct abbrev_info **m_abbrevs;
};

typedef std::unique_ptr<struct abbrev_table> abbrev_table_up;

/* Attributes have a name and a value.  */
struct attribute
  {
    ENUM_BITFIELD(dwarf_attribute) name : 16;
    ENUM_BITFIELD(dwarf_form) form : 15;

    /* Has DW_STRING already been updated by dwarf2_canonicalize_name?  This
       field should be in u.str (existing only for DW_STRING) but it is kept
       here for better struct attribute alignment.  */
    unsigned int string_is_canonical : 1;

    union
      {
	const char *str;
	struct dwarf_block *blk;
	ULONGEST unsnd;
	LONGEST snd;
	CORE_ADDR addr;
	ULONGEST signature;
      }
    u;
  };

/* This data structure holds a complete die structure.  */
struct die_info
  {
    /* DWARF-2 tag for this DIE.  */
    ENUM_BITFIELD(dwarf_tag) tag : 16;

    /* Number of attributes */
    unsigned char num_attrs;

    /* True if we're presently building the full type name for the
       type derived from this DIE.  */
    unsigned char building_fullname : 1;

    /* True if this die is in process.  PR 16581.  */
    unsigned char in_process : 1;

    /* Abbrev number */
    unsigned int abbrev;

    /* Offset in .debug_info or .debug_types section.  */
    sect_offset sect_off;

    /* The dies in a compilation unit form an n-ary tree.  PARENT
       points to this die's parent; CHILD points to the first child of
       this node; and all the children of a given node are chained
       together via their SIBLING fields.  */
    struct die_info *child;	/* Its first child, if any.  */
    struct die_info *sibling;	/* Its next sibling, if any.  */
    struct die_info *parent;	/* Its parent, if any.  */

    /* An array of attributes, with NUM_ATTRS elements.  There may be
       zero, but it's not common and zero-sized arrays are not
       sufficiently portable C.  */
    struct attribute attrs[1];
  };

/* Get at parts of an attribute structure.  */

#define DW_STRING(attr)    ((attr)->u.str)
#define DW_STRING_IS_CANONICAL(attr) ((attr)->string_is_canonical)
#define DW_UNSND(attr)     ((attr)->u.unsnd)
#define DW_BLOCK(attr)     ((attr)->u.blk)
#define DW_SND(attr)       ((attr)->u.snd)
#define DW_ADDR(attr)	   ((attr)->u.addr)
#define DW_SIGNATURE(attr) ((attr)->u.signature)

/* Blocks are a bunch of untyped bytes.  */
struct dwarf_block
  {
    size_t size;

    /* Valid only if SIZE is not zero.  */
    const gdb_byte *data;
  };

#ifndef ATTR_ALLOC_CHUNK
#define ATTR_ALLOC_CHUNK 4
#endif

/* Allocate fields for structs, unions and enums in this size.  */
#ifndef DW_FIELD_ALLOC_CHUNK
#define DW_FIELD_ALLOC_CHUNK 4
#endif

/* FIXME: We might want to set this from BFD via bfd_arch_bits_per_byte,
   but this would require a corresponding change in unpack_field_as_long
   and friends.  */
static int bits_per_byte = 8;

/* When reading a variant or variant part, we track a bit more
   information about the field, and store it in an object of this
   type.  */

struct variant_field
{
  /* If we see a DW_TAG_variant, then this will be the discriminant
     value.  */
  ULONGEST discriminant_value;
  /* If we see a DW_TAG_variant, then this will be set if this is the
     default branch.  */
  bool default_branch;
  /* While reading a DW_TAG_variant_part, this will be set if this
     field is the discriminant.  */
  bool is_discriminant;
};

struct nextfield
{
  int accessibility = 0;
  int virtuality = 0;
  /* Extra information to describe a variant or variant part.  */
  struct variant_field variant {};
  struct field field {};
};

struct fnfieldlist
{
  const char *name = nullptr;
  std::vector<struct fn_field> fnfields;
};

/* The routines that read and process dies for a C struct or C++ class
   pass lists of data member fields and lists of member function fields
   in an instance of a field_info structure, as defined below.  */
struct field_info
  {
    /* List of data member and baseclasses fields.  */
    std::vector<struct nextfield> fields;
    std::vector<struct nextfield> baseclasses;

    /* Number of fields (including baseclasses).  */
    int nfields = 0;

    /* Set if the accessibility of one of the fields is not public.  */
    int non_public_fields = 0;

    /* Member function fieldlist array, contains name of possibly overloaded
       member function, number of overloaded member functions and a pointer
       to the head of the member function field chain.  */
    std::vector<struct fnfieldlist> fnfieldlists;

    /* typedefs defined inside this class.  TYPEDEF_FIELD_LIST contains head of
       a NULL terminated list of TYPEDEF_FIELD_LIST_COUNT elements.  */
    std::vector<struct decl_field> typedef_field_list;

    /* Nested types defined by this class and the number of elements in this
       list.  */
    std::vector<struct decl_field> nested_types_list;
  };

/* One item on the queue of compilation units to read in full symbols
   for.  */
struct dwarf2_queue_item
{
  struct dwarf2_per_cu_data *per_cu;
  enum language pretend_language;
  struct dwarf2_queue_item *next;
};

/* The current queue.  */
static struct dwarf2_queue_item *dwarf2_queue, *dwarf2_queue_tail;

/* Loaded secondary compilation units are kept in memory until they
   have not been referenced for the processing of this many
   compilation units.  Set this to zero to disable caching.  Cache
   sizes of up to at least twenty will improve startup time for
   typical inter-CU-reference binaries, at an obvious memory cost.  */
static int dwarf_max_cache_age = 5;
static void
show_dwarf_max_cache_age (struct ui_file *file, int from_tty,
			  struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("The upper bound on the age of cached "
			    "DWARF compilation units is %s.\n"),
		    value);
}

/* local function prototypes */

static const char *get_section_name (const struct dwarf2_section_info *);

static const char *get_section_file_name (const struct dwarf2_section_info *);

static void dwarf2_find_base_address (struct die_info *die,
				      struct dwarf2_cu *cu);

static struct partial_symtab *create_partial_symtab
  (struct dwarf2_per_cu_data *per_cu, const char *name);

static void build_type_psymtabs_reader (const struct die_reader_specs *reader,
					const gdb_byte *info_ptr,
					struct die_info *type_unit_die,
					int has_children, void *data);

static void dwarf2_build_psymtabs_hard
  (struct dwarf2_per_objfile *dwarf2_per_objfile);

static void scan_partial_symbols (struct partial_die_info *,
				  CORE_ADDR *, CORE_ADDR *,
				  int, struct dwarf2_cu *);

static void add_partial_symbol (struct partial_die_info *,
				struct dwarf2_cu *);

static void add_partial_namespace (struct partial_die_info *pdi,
				   CORE_ADDR *lowpc, CORE_ADDR *highpc,
				   int set_addrmap, struct dwarf2_cu *cu);

static void add_partial_module (struct partial_die_info *pdi, CORE_ADDR *lowpc,
				CORE_ADDR *highpc, int set_addrmap,
				struct dwarf2_cu *cu);

static void add_partial_enumeration (struct partial_die_info *enum_pdi,
				     struct dwarf2_cu *cu);

static void add_partial_subprogram (struct partial_die_info *pdi,
				    CORE_ADDR *lowpc, CORE_ADDR *highpc,
				    int need_pc, struct dwarf2_cu *cu);

static void dwarf2_read_symtab (struct partial_symtab *,
				struct objfile *);

static void psymtab_to_symtab_1 (struct partial_symtab *);

static abbrev_table_up abbrev_table_read_table
  (struct dwarf2_per_objfile *dwarf2_per_objfile, struct dwarf2_section_info *,
   sect_offset);

static unsigned int peek_abbrev_code (bfd *, const gdb_byte *);

static struct partial_die_info *load_partial_dies
  (const struct die_reader_specs *, const gdb_byte *, int);

/* A pair of partial_die_info and compilation unit.  */
struct cu_partial_die_info
{
  /* The compilation unit of the partial_die_info.  */
  struct dwarf2_cu *cu;
  /* A partial_die_info.  */
  struct partial_die_info *pdi;

  cu_partial_die_info (struct dwarf2_cu *cu, struct partial_die_info *pdi)
    : cu (cu),
      pdi (pdi)
  { /* Nothing.  */ }

private:
  cu_partial_die_info () = delete;
};

static const struct cu_partial_die_info find_partial_die (sect_offset, int,
							  struct dwarf2_cu *);

static const gdb_byte *read_attribute (const struct die_reader_specs *,
				       struct attribute *, struct attr_abbrev *,
				       const gdb_byte *, bool *need_reprocess);

static void read_attribute_reprocess (const struct die_reader_specs *reader,
				      struct attribute *attr);

static CORE_ADDR read_addr_index (struct dwarf2_cu *cu, unsigned int addr_index);

static unsigned int read_1_byte (bfd *, const gdb_byte *);

static int read_1_signed_byte (bfd *, const gdb_byte *);

static unsigned int read_2_bytes (bfd *, const gdb_byte *);

/* Read the next three bytes (little-endian order) as an unsigned integer.  */
static unsigned int read_3_bytes (bfd *, const gdb_byte *);

static unsigned int read_4_bytes (bfd *, const gdb_byte *);

static ULONGEST read_8_bytes (bfd *, const gdb_byte *);

static CORE_ADDR read_address (bfd *, const gdb_byte *ptr, struct dwarf2_cu *,
			       unsigned int *);

static LONGEST read_initial_length (bfd *, const gdb_byte *, unsigned int *);

static LONGEST read_checked_initial_length_and_offset
  (bfd *, const gdb_byte *, const struct comp_unit_head *,
   unsigned int *, unsigned int *);

static LONGEST read_offset (bfd *, const gdb_byte *,
			    const struct comp_unit_head *,
			    unsigned int *);

static LONGEST read_offset_1 (bfd *, const gdb_byte *, unsigned int);

static sect_offset read_abbrev_offset
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   struct dwarf2_section_info *, sect_offset);

static const gdb_byte *read_n_bytes (bfd *, const gdb_byte *, unsigned int);

static const char *read_direct_string (bfd *, const gdb_byte *, unsigned int *);

static const char *read_indirect_string
  (struct dwarf2_per_objfile *dwarf2_per_objfile, bfd *, const gdb_byte *,
   const struct comp_unit_head *, unsigned int *);

static const char *read_indirect_line_string
  (struct dwarf2_per_objfile *dwarf2_per_objfile, bfd *, const gdb_byte *,
   const struct comp_unit_head *, unsigned int *);

static const char *read_indirect_string_at_offset
  (struct dwarf2_per_objfile *dwarf2_per_objfile, bfd *abfd,
   LONGEST str_offset);

static const char *read_indirect_string_from_dwz
  (struct objfile *objfile, struct dwz_file *, LONGEST);

static LONGEST read_signed_leb128 (bfd *, const gdb_byte *, unsigned int *);

static CORE_ADDR read_addr_index_from_leb128 (struct dwarf2_cu *,
					      const gdb_byte *,
					      unsigned int *);

static const char *read_dwo_str_index (const struct die_reader_specs *reader,
				       ULONGEST str_index);

static const char *read_stub_str_index (struct dwarf2_cu *cu,
					ULONGEST str_index);

static void set_cu_language (unsigned int, struct dwarf2_cu *);

static struct attribute *dwarf2_attr (struct die_info *, unsigned int,
				      struct dwarf2_cu *);

static struct attribute *dwarf2_attr_no_follow (struct die_info *,
						unsigned int);

static const char *dwarf2_string_attr (struct die_info *die, unsigned int name,
                                       struct dwarf2_cu *cu);

static const char *dwarf2_dwo_name (struct die_info *die, struct dwarf2_cu *cu);

static int dwarf2_flag_true_p (struct die_info *die, unsigned name,
                               struct dwarf2_cu *cu);

static int die_is_declaration (struct die_info *, struct dwarf2_cu *cu);

static struct die_info *die_specification (struct die_info *die,
					   struct dwarf2_cu **);

static line_header_up dwarf_decode_line_header (sect_offset sect_off,
						struct dwarf2_cu *cu);

static void dwarf_decode_lines (struct line_header *, const char *,
				struct dwarf2_cu *, struct partial_symtab *,
				CORE_ADDR, int decode_mapping);

static void dwarf2_start_subfile (struct dwarf2_cu *, const char *,
				  const char *);

static struct symbol *new_symbol (struct die_info *, struct type *,
				  struct dwarf2_cu *, struct symbol * = NULL);

static void dwarf2_const_value (const struct attribute *, struct symbol *,
				struct dwarf2_cu *);

static void dwarf2_const_value_attr (const struct attribute *attr,
				     struct type *type,
				     const char *name,
				     struct obstack *obstack,
				     struct dwarf2_cu *cu, LONGEST *value,
				     const gdb_byte **bytes,
				     struct dwarf2_locexpr_baton **baton);

static struct type *die_type (struct die_info *, struct dwarf2_cu *);

static int need_gnat_info (struct dwarf2_cu *);

static struct type *die_descriptive_type (struct die_info *,
					  struct dwarf2_cu *);

static void set_descriptive_type (struct type *, struct die_info *,
				  struct dwarf2_cu *);

static struct type *die_containing_type (struct die_info *,
					 struct dwarf2_cu *);

static struct type *lookup_die_type (struct die_info *, const struct attribute *,
				     struct dwarf2_cu *);

static struct type *read_type_die (struct die_info *, struct dwarf2_cu *);

static struct type *read_type_die_1 (struct die_info *, struct dwarf2_cu *);

static const char *determine_prefix (struct die_info *die, struct dwarf2_cu *);

static char *typename_concat (struct obstack *obs, const char *prefix,
			      const char *suffix, int physname,
			      struct dwarf2_cu *cu);

static void read_file_scope (struct die_info *, struct dwarf2_cu *);

static void read_type_unit_scope (struct die_info *, struct dwarf2_cu *);

static void read_func_scope (struct die_info *, struct dwarf2_cu *);

static void read_lexical_block_scope (struct die_info *, struct dwarf2_cu *);

static void read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu);

static void read_variable (struct die_info *die, struct dwarf2_cu *cu);

static int dwarf2_ranges_read (unsigned, CORE_ADDR *, CORE_ADDR *,
			       struct dwarf2_cu *, struct partial_symtab *,
                               dwarf_tag tag);

static struct dwarf2_section_info *cu_debug_loc_section (struct dwarf2_cu *cu);
static struct dwarf2_section_info
*cu_debug_rnglist_section (struct dwarf2_cu *cu);

static CORE_ADDR read_loclist_index (struct dwarf2_cu *cu,
				     ULONGEST loclist_index);
static ULONGEST lookup_loclist_base (struct dwarf2_cu *cu);
static struct loclist_header read_loclist_header (struct dwarf2_cu *cu,
						  bfd *abfd,
						  const gdb_byte *info_ptr);

/* How dwarf2_get_pc_bounds constructed its *LOWPC and *HIGHPC return
   values.  Keep the items ordered with increasing constraints compliance.  */
enum pc_bounds_kind
{
  /* No attribute DW_AT_low_pc, DW_AT_high_pc or DW_AT_ranges was found.  */
  PC_BOUNDS_NOT_PRESENT,

  /* Some of the attributes DW_AT_low_pc, DW_AT_high_pc or DW_AT_ranges
     were present but they do not form a valid range of PC addresses.  */
  PC_BOUNDS_INVALID,

  /* Discontiguous range was found - that is DW_AT_ranges was found.  */
  PC_BOUNDS_RANGES,

  /* Contiguous range was found - DW_AT_low_pc and DW_AT_high_pc were found.  */
  PC_BOUNDS_HIGH_LOW,
};

static enum pc_bounds_kind dwarf2_get_pc_bounds (struct die_info *,
						 CORE_ADDR *, CORE_ADDR *,
						 struct dwarf2_cu *,
						 struct partial_symtab *);

static void get_scope_pc_bounds (struct die_info *,
				 CORE_ADDR *, CORE_ADDR *,
				 struct dwarf2_cu *);

static void dwarf2_record_block_ranges (struct die_info *, struct block *,
                                        CORE_ADDR, struct dwarf2_cu *);

static void dwarf2_add_field (struct field_info *, struct die_info *,
			      struct dwarf2_cu *);

static void dwarf2_attach_fields_to_type (struct field_info *,
					  struct type *, struct dwarf2_cu *);

static void dwarf2_add_member_fn (struct field_info *,
				  struct die_info *, struct type *,
				  struct dwarf2_cu *);

static void dwarf2_attach_fn_fields_to_type (struct field_info *,
					     struct type *,
					     struct dwarf2_cu *);

static void process_structure_scope (struct die_info *, struct dwarf2_cu *);

static void read_common_block (struct die_info *, struct dwarf2_cu *);

static void read_namespace (struct die_info *die, struct dwarf2_cu *);

static void read_module (struct die_info *die, struct dwarf2_cu *cu);

static struct using_direct **using_directives (struct dwarf2_cu *cu);

static void read_import_statement (struct die_info *die, struct dwarf2_cu *);

static int read_namespace_alias (struct die_info *die, struct dwarf2_cu *cu);

static struct type *read_module_type (struct die_info *die,
				      struct dwarf2_cu *cu);

static const char *namespace_name (struct die_info *die,
				   int *is_anonymous, struct dwarf2_cu *);

static void process_enumeration_scope (struct die_info *, struct dwarf2_cu *);

static CORE_ADDR decode_locdesc (struct dwarf_block *, struct dwarf2_cu *);

static enum dwarf_array_dim_ordering read_array_order (struct die_info *,
						       struct dwarf2_cu *);

static struct die_info *read_die_and_siblings_1
  (const struct die_reader_specs *, const gdb_byte *, const gdb_byte **,
   struct die_info *);

static struct die_info *read_die_and_siblings (const struct die_reader_specs *,
					       const gdb_byte *info_ptr,
					       const gdb_byte **new_info_ptr,
					       struct die_info *parent);

static const gdb_byte *read_full_die_1 (const struct die_reader_specs *,
					struct die_info **, const gdb_byte *,
					int *, int);

static const gdb_byte *read_full_die (const struct die_reader_specs *,
				      struct die_info **, const gdb_byte *,
				      int *);

static void process_die (struct die_info *, struct dwarf2_cu *);

static const char *dwarf2_canonicalize_name (const char *, struct dwarf2_cu *,
					     struct obstack *);

static const char *dwarf2_name (struct die_info *die, struct dwarf2_cu *);

static const char *dwarf2_full_name (const char *name,
				     struct die_info *die,
				     struct dwarf2_cu *cu);

static const char *dwarf2_physname (const char *name, struct die_info *die,
				    struct dwarf2_cu *cu);

static struct die_info *dwarf2_extension (struct die_info *die,
					  struct dwarf2_cu **);

static const char *dwarf_tag_name (unsigned int);

static const char *dwarf_attr_name (unsigned int);

static const char *dwarf_unit_type_name (int unit_type);

static const char *dwarf_form_name (unsigned int);

static const char *dwarf_bool_name (unsigned int);

static const char *dwarf_type_encoding_name (unsigned int);

static struct die_info *sibling_die (struct die_info *);

static void dump_die_shallow (struct ui_file *, int indent, struct die_info *);

static void dump_die_for_error (struct die_info *);

static void dump_die_1 (struct ui_file *, int level, int max_level,
			struct die_info *);

/*static*/ void dump_die (struct die_info *, int max_level);

static void store_in_ref_table (struct die_info *,
				struct dwarf2_cu *);

static sect_offset dwarf2_get_ref_die_offset (const struct attribute *);

static LONGEST dwarf2_get_attr_constant_value (const struct attribute *, int);

static struct die_info *follow_die_ref_or_sig (struct die_info *,
					       const struct attribute *,
					       struct dwarf2_cu **);

static struct die_info *follow_die_ref (struct die_info *,
					const struct attribute *,
					struct dwarf2_cu **);

static struct die_info *follow_die_sig (struct die_info *,
					const struct attribute *,
					struct dwarf2_cu **);

static struct type *get_signatured_type (struct die_info *, ULONGEST,
					 struct dwarf2_cu *);

static struct type *get_DW_AT_signature_type (struct die_info *,
					      const struct attribute *,
					      struct dwarf2_cu *);

static void load_full_type_unit (struct dwarf2_per_cu_data *per_cu);

static void read_signatured_type (struct signatured_type *);

static int attr_to_dynamic_prop (const struct attribute *attr,
				 struct die_info *die, struct dwarf2_cu *cu,
				 struct dynamic_prop *prop, struct type *type);

/* memory allocation interface */

static struct dwarf_block *dwarf_alloc_block (struct dwarf2_cu *);

static struct die_info *dwarf_alloc_die (struct dwarf2_cu *, int);

static void dwarf_decode_macros (struct dwarf2_cu *, unsigned int, int);

static int attr_form_is_block (const struct attribute *);

static int attr_form_is_section_offset (const struct attribute *);

static int attr_form_is_constant (const struct attribute *);

static int attr_form_is_ref (const struct attribute *);

static void fill_in_loclist_baton (struct dwarf2_cu *cu,
				   struct dwarf2_loclist_baton *baton,
				   const struct attribute *attr);

static void dwarf2_symbol_mark_computed (const struct attribute *attr,
					 struct symbol *sym,
					 struct dwarf2_cu *cu,
					 int is_block);

static const gdb_byte *skip_one_die (const struct die_reader_specs *reader,
				     const gdb_byte *info_ptr,
				     struct abbrev_info *abbrev);

static hashval_t partial_die_hash (const void *item);

static int partial_die_eq (const void *item_lhs, const void *item_rhs);

static struct dwarf2_per_cu_data *dwarf2_find_containing_comp_unit
  (sect_offset sect_off, unsigned int offset_in_dwz,
   struct dwarf2_per_objfile *dwarf2_per_objfile);

static void prepare_one_comp_unit (struct dwarf2_cu *cu,
				   struct die_info *comp_unit_die,
				   enum language pretend_language);

static void age_cached_comp_units (struct dwarf2_per_objfile *dwarf2_per_objfile);

static void free_one_cached_comp_unit (struct dwarf2_per_cu_data *);

static struct type *set_die_type (struct die_info *, struct type *,
				  struct dwarf2_cu *);

static void create_all_comp_units (struct dwarf2_per_objfile *dwarf2_per_objfile);

static int create_all_type_units (struct dwarf2_per_objfile *dwarf2_per_objfile);

static void load_full_comp_unit (struct dwarf2_per_cu_data *, bool,
				 enum language);

static void process_full_comp_unit (struct dwarf2_per_cu_data *,
				    enum language);

static void process_full_type_unit (struct dwarf2_per_cu_data *,
				    enum language);

static void dwarf2_add_dependence (struct dwarf2_cu *,
				   struct dwarf2_per_cu_data *);

static void dwarf2_mark (struct dwarf2_cu *);

static void dwarf2_clear_marks (struct dwarf2_per_cu_data *);

static struct type *get_die_type_at_offset (sect_offset,
					    struct dwarf2_per_cu_data *);

static struct type *get_die_type (struct die_info *die, struct dwarf2_cu *cu);

static void queue_comp_unit (struct dwarf2_per_cu_data *per_cu,
			     enum language pretend_language);

static void process_queue (struct dwarf2_per_objfile *dwarf2_per_objfile);

static struct type *dwarf2_per_cu_addr_type (struct dwarf2_per_cu_data *per_cu);
static struct type *dwarf2_per_cu_addr_sized_int_type
	(struct dwarf2_per_cu_data *per_cu, bool unsigned_p);
static struct type *dwarf2_per_cu_int_type
	(struct dwarf2_per_cu_data *per_cu, int size_in_bytes,
	 bool unsigned_p);

/* Class, the destructor of which frees all allocated queue entries.  This
   will only have work to do if an error was thrown while processing the
   dwarf.  If no error was thrown then the queue entries should have all
   been processed, and freed, as we went along.  */

class dwarf2_queue_guard
{
public:
  dwarf2_queue_guard () = default;

  /* Free any entries remaining on the queue.  There should only be
     entries left if we hit an error while processing the dwarf.  */
  ~dwarf2_queue_guard ()
  {
    struct dwarf2_queue_item *item, *last;

    item = dwarf2_queue;
    while (item)
      {
	/* Anything still marked queued is likely to be in an
	   inconsistent state, so discard it.  */
	if (item->per_cu->queued)
	  {
	    if (item->per_cu->cu != NULL)
	      free_one_cached_comp_unit (item->per_cu);
	    item->per_cu->queued = 0;
	  }

	last = item;
	item = item->next;
	xfree (last);
      }

    dwarf2_queue = dwarf2_queue_tail = NULL;
  }
};

/* The return type of find_file_and_directory.  Note, the enclosed
   string pointers are only valid while this object is valid.  */

struct file_and_directory
{
  /* The filename.  This is never NULL.  */
  const char *name;

  /* The compilation directory.  NULL if not known.  If we needed to
     compute a new string, this points to COMP_DIR_STORAGE, otherwise,
     points directly to the DW_AT_comp_dir string attribute owned by
     the obstack that owns the DIE.  */
  const char *comp_dir;

  /* If we needed to build a new string for comp_dir, this is what
     owns the storage.  */
  std::string comp_dir_storage;
};

static file_and_directory find_file_and_directory (struct die_info *die,
						   struct dwarf2_cu *cu);

static char *file_full_name (int file, struct line_header *lh,
			     const char *comp_dir);

/* Expected enum dwarf_unit_type for read_comp_unit_head.  */
enum class rcuh_kind { COMPILE, TYPE };

static const gdb_byte *read_and_check_comp_unit_head
  (struct dwarf2_per_objfile* dwarf2_per_objfile,
   struct comp_unit_head *header,
   struct dwarf2_section_info *section,
   struct dwarf2_section_info *abbrev_section, const gdb_byte *info_ptr,
   rcuh_kind section_kind);

static void init_cutu_and_read_dies
  (struct dwarf2_per_cu_data *this_cu, struct abbrev_table *abbrev_table,
   int use_existing_cu, int keep, bool skip_partial,
   die_reader_func_ftype *die_reader_func, void *data);

static void init_cutu_and_read_dies_simple
  (struct dwarf2_per_cu_data *this_cu,
   die_reader_func_ftype *die_reader_func, void *data);

static htab_t allocate_signatured_type_table (struct objfile *objfile);

static htab_t allocate_dwo_unit_table (struct objfile *objfile);

static struct dwo_unit *lookup_dwo_unit_in_dwp
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   struct dwp_file *dwp_file, const char *comp_dir,
   ULONGEST signature, int is_debug_types);

static struct dwp_file *get_dwp_file
  (struct dwarf2_per_objfile *dwarf2_per_objfile);

static struct dwo_unit *lookup_dwo_comp_unit
  (struct dwarf2_per_cu_data *, const char *, const char *, ULONGEST);

static struct dwo_unit *lookup_dwo_type_unit
  (struct signatured_type *, const char *, const char *);

static void queue_and_load_all_dwo_tus (struct dwarf2_per_cu_data *);

/* A unique pointer to a dwo_file.  */

typedef std::unique_ptr<struct dwo_file> dwo_file_up;

static void process_cu_includes (struct dwarf2_per_objfile *dwarf2_per_objfile);

static void check_producer (struct dwarf2_cu *cu);

static void free_line_header_voidp (void *arg);

/* Various complaints about symbol reading that don't abort the process.  */

static void
dwarf2_statement_list_fits_in_line_number_section_complaint (void)
{
  complaint (_("statement list doesn't fit in .debug_line section"));
}

static void
dwarf2_debug_line_missing_file_complaint (void)
{
  complaint (_(".debug_line section has line data without a file"));
}

static void
dwarf2_debug_line_missing_end_sequence_complaint (void)
{
  complaint (_(".debug_line section has line "
	       "program sequence without an end"));
}

static void
dwarf2_complex_location_expr_complaint (void)
{
  complaint (_("location expression too complex"));
}

static void
dwarf2_const_value_length_mismatch_complaint (const char *arg1, int arg2,
					      int arg3)
{
  complaint (_("const value length mismatch for '%s', got %d, expected %d"),
	     arg1, arg2, arg3);
}

static void
dwarf2_section_buffer_overflow_complaint (struct dwarf2_section_info *section)
{
  complaint (_("debug info runs off end of %s section"
	       " [in module %s]"),
	     get_section_name (section),
	     get_section_file_name (section));
}

static void
dwarf2_macro_malformed_definition_complaint (const char *arg1)
{
  complaint (_("macro debug info contains a "
	       "malformed macro definition:\n`%s'"),
	     arg1);
}

static void
dwarf2_invalid_attrib_class_complaint (const char *arg1, const char *arg2)
{
  complaint (_("invalid attribute class or form for '%s' in '%s'"),
	     arg1, arg2);
}

/* Hash function for line_header_hash.  */

static hashval_t
line_header_hash (const struct line_header *ofs)
{
  return to_underlying (ofs->sect_off) ^ ofs->offset_in_dwz;
}

/* Hash function for htab_create_alloc_ex for line_header_hash.  */

static hashval_t
line_header_hash_voidp (const void *item)
{
  const struct line_header *ofs = (const struct line_header *) item;

  return line_header_hash (ofs);
}

/* Equality function for line_header_hash.  */

static int
line_header_eq_voidp (const void *item_lhs, const void *item_rhs)
{
  const struct line_header *ofs_lhs = (const struct line_header *) item_lhs;
  const struct line_header *ofs_rhs = (const struct line_header *) item_rhs;

  return (ofs_lhs->sect_off == ofs_rhs->sect_off
	  && ofs_lhs->offset_in_dwz == ofs_rhs->offset_in_dwz);
}



/* Read the given attribute value as an address, taking the attribute's
   form into account.  */

static CORE_ADDR
attr_value_as_address (struct attribute *attr)
{
  CORE_ADDR addr;

  if (attr->form != DW_FORM_addr && attr->form != DW_FORM_addrx
      && attr->form != DW_FORM_GNU_addr_index)
    {
      /* Aside from a few clearly defined exceptions, attributes that
	 contain an address must always be in DW_FORM_addr form.
	 Unfortunately, some compilers happen to be violating this
	 requirement by encoding addresses using other forms, such
	 as DW_FORM_data4 for example.  For those broken compilers,
	 we try to do our best, without any guarantee of success,
	 to interpret the address correctly.  It would also be nice
	 to generate a complaint, but that would require us to maintain
	 a list of legitimate cases where a non-address form is allowed,
	 as well as update callers to pass in at least the CU's DWARF
	 version.  This is more overhead than what we're willing to
	 expand for a pretty rare case.  */
      addr = DW_UNSND (attr);
    }
  else
    addr = DW_ADDR (attr);

  return addr;
}

/* See declaration.  */

dwarf2_per_objfile::dwarf2_per_objfile (struct objfile *objfile_,
					const dwarf2_debug_sections *names,
					bool can_copy_)
  : objfile (objfile_),
    can_copy (can_copy_)
{
  if (names == NULL)
    names = &dwarf2_elf_names;

  bfd *obfd = objfile->obfd;

  for (asection *sec = obfd->sections; sec != NULL; sec = sec->next)
    locate_sections (obfd, sec, *names);
}

dwarf2_per_objfile::~dwarf2_per_objfile ()
{
  /* Cached DIE trees use xmalloc and the comp_unit_obstack.  */
  free_cached_comp_units ();

  if (quick_file_names_table)
    htab_delete (quick_file_names_table);

  if (line_header_hash)
    htab_delete (line_header_hash);

  for (dwarf2_per_cu_data *per_cu : all_comp_units)
    per_cu->imported_symtabs_free ();

  for (signatured_type *sig_type : all_type_units)
    sig_type->per_cu.imported_symtabs_free ();

  /* Everything else should be on the objfile obstack.  */
}

/* See declaration.  */

void
dwarf2_per_objfile::free_cached_comp_units ()
{
  dwarf2_per_cu_data *per_cu = read_in_chain;
  dwarf2_per_cu_data **last_chain = &read_in_chain;
  while (per_cu != NULL)
    {
      dwarf2_per_cu_data *next_cu = per_cu->cu->read_in_chain;

      delete per_cu->cu;
      *last_chain = next_cu;
      per_cu = next_cu;
    }
}

/* A helper class that calls free_cached_comp_units on
   destruction.  */

class free_cached_comp_units
{
public:

  explicit free_cached_comp_units (dwarf2_per_objfile *per_objfile)
    : m_per_objfile (per_objfile)
  {
  }

  ~free_cached_comp_units ()
  {
    m_per_objfile->free_cached_comp_units ();
  }

  DISABLE_COPY_AND_ASSIGN (free_cached_comp_units);

private:

  dwarf2_per_objfile *m_per_objfile;
};

/* Try to locate the sections we need for DWARF 2 debugging
   information and return true if we have enough to do something.
   NAMES points to the dwarf2 section names, or is NULL if the standard
   ELF names are used.  CAN_COPY is true for formats where symbol
   interposition is possible and so symbol values must follow copy
   relocation rules.  */

int
dwarf2_has_info (struct objfile *objfile,
                 const struct dwarf2_debug_sections *names,
		 bool can_copy)
{
  if (objfile->flags & OBJF_READNEVER)
    return 0;

  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  if (dwarf2_per_objfile == NULL)
    dwarf2_per_objfile = dwarf2_objfile_data_key.emplace (objfile, objfile,
							  names,
							  can_copy);

  return (!dwarf2_per_objfile->info.is_virtual
	  && dwarf2_per_objfile->info.s.section != NULL
	  && !dwarf2_per_objfile->abbrev.is_virtual
	  && dwarf2_per_objfile->abbrev.s.section != NULL);
}

/* Return the containing section of virtual section SECTION.  */

static struct dwarf2_section_info *
get_containing_section (const struct dwarf2_section_info *section)
{
  gdb_assert (section->is_virtual);
  return section->s.containing_section;
}

/* Return the bfd owner of SECTION.  */

static struct bfd *
get_section_bfd_owner (const struct dwarf2_section_info *section)
{
  if (section->is_virtual)
    {
      section = get_containing_section (section);
      gdb_assert (!section->is_virtual);
    }
  return section->s.section->owner;
}

/* Return the bfd section of SECTION.
   Returns NULL if the section is not present.  */

static asection *
get_section_bfd_section (const struct dwarf2_section_info *section)
{
  if (section->is_virtual)
    {
      section = get_containing_section (section);
      gdb_assert (!section->is_virtual);
    }
  return section->s.section;
}

/* Return the name of SECTION.  */

static const char *
get_section_name (const struct dwarf2_section_info *section)
{
  asection *sectp = get_section_bfd_section (section);

  gdb_assert (sectp != NULL);
  return bfd_section_name (sectp);
}

/* Return the name of the file SECTION is in.  */

static const char *
get_section_file_name (const struct dwarf2_section_info *section)
{
  bfd *abfd = get_section_bfd_owner (section);

  return bfd_get_filename (abfd);
}

/* Return the id of SECTION.
   Returns 0 if SECTION doesn't exist.  */

static int
get_section_id (const struct dwarf2_section_info *section)
{
  asection *sectp = get_section_bfd_section (section);

  if (sectp == NULL)
    return 0;
  return sectp->id;
}

/* Return the flags of SECTION.
   SECTION (or containing section if this is a virtual section) must exist.  */

static int
get_section_flags (const struct dwarf2_section_info *section)
{
  asection *sectp = get_section_bfd_section (section);

  gdb_assert (sectp != NULL);
  return bfd_section_flags (sectp);
}

/* When loading sections, we look either for uncompressed section or for
   compressed section names.  */

static int
section_is_p (const char *section_name,
              const struct dwarf2_section_names *names)
{
  if (names->normal != NULL
      && strcmp (section_name, names->normal) == 0)
    return 1;
  if (names->compressed != NULL
      && strcmp (section_name, names->compressed) == 0)
    return 1;
  return 0;
}

/* See declaration.  */

void
dwarf2_per_objfile::locate_sections (bfd *abfd, asection *sectp,
				     const dwarf2_debug_sections &names)
{
  flagword aflag = bfd_section_flags (sectp);

  if ((aflag & SEC_HAS_CONTENTS) == 0)
    {
    }
  else if (elf_section_data (sectp)->this_hdr.sh_size
	   > bfd_get_file_size (abfd))
    {
      bfd_size_type size = elf_section_data (sectp)->this_hdr.sh_size;
      warning (_("Discarding section %s which has a section size (%s"
		 ") larger than the file size [in module %s]"),
	       bfd_section_name (sectp), phex_nz (size, sizeof (size)),
	       bfd_get_filename (abfd));
    }
  else if (section_is_p (sectp->name, &names.info))
    {
      this->info.s.section = sectp;
      this->info.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.abbrev))
    {
      this->abbrev.s.section = sectp;
      this->abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.line))
    {
      this->line.s.section = sectp;
      this->line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.loc))
    {
      this->loc.s.section = sectp;
      this->loc.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.loclists))
    {
      this->loclists.s.section = sectp;
      this->loclists.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.macinfo))
    {
      this->macinfo.s.section = sectp;
      this->macinfo.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.macro))
    {
      this->macro.s.section = sectp;
      this->macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.str))
    {
      this->str.s.section = sectp;
      this->str.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.str_offsets))
    {
      this->str_offsets.s.section = sectp;
      this->str_offsets.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.line_str))
    {
      this->line_str.s.section = sectp;
      this->line_str.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.addr))
    {
      this->addr.s.section = sectp;
      this->addr.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.frame))
    {
      this->frame.s.section = sectp;
      this->frame.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.eh_frame))
    {
      this->eh_frame.s.section = sectp;
      this->eh_frame.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.ranges))
    {
      this->ranges.s.section = sectp;
      this->ranges.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.rnglists))
    {
      this->rnglists.s.section = sectp;
      this->rnglists.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.types))
    {
      struct dwarf2_section_info type_section;

      memset (&type_section, 0, sizeof (type_section));
      type_section.s.section = sectp;
      type_section.size = bfd_section_size (sectp);

      this->types.push_back (type_section);
    }
  else if (section_is_p (sectp->name, &names.gdb_index))
    {
      this->gdb_index.s.section = sectp;
      this->gdb_index.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.debug_names))
    {
      this->debug_names.s.section = sectp;
      this->debug_names.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names.debug_aranges))
    {
      this->debug_aranges.s.section = sectp;
      this->debug_aranges.size = bfd_section_size (sectp);
    }

  if ((bfd_section_flags (sectp) & (SEC_LOAD | SEC_ALLOC))
      && bfd_section_vma (sectp) == 0)
    this->has_section_at_zero = true;
}

/* A helper function that decides whether a section is empty,
   or not present.  */

static int
dwarf2_section_empty_p (const struct dwarf2_section_info *section)
{
  if (section->is_virtual)
    return section->size == 0;
  return section->s.section == NULL || section->size == 0;
}

/* See dwarf2read.h.  */

void
dwarf2_read_section (struct objfile *objfile, dwarf2_section_info *info)
{
  asection *sectp;
  bfd *abfd;
  gdb_byte *buf, *retbuf;

  if (info->readin)
    return;
  info->buffer = NULL;
  info->readin = true;

  if (dwarf2_section_empty_p (info))
    return;

  sectp = get_section_bfd_section (info);

  /* If this is a virtual section we need to read in the real one first.  */
  if (info->is_virtual)
    {
      struct dwarf2_section_info *containing_section =
	get_containing_section (info);

      gdb_assert (sectp != NULL);
      if ((sectp->flags & SEC_RELOC) != 0)
	{
	  error (_("Dwarf Error: DWP format V2 with relocations is not"
		   " supported in section %s [in module %s]"),
		 get_section_name (info), get_section_file_name (info));
	}
      dwarf2_read_section (objfile, containing_section);
      /* Other code should have already caught virtual sections that don't
	 fit.  */
      gdb_assert (info->virtual_offset + info->size
		  <= containing_section->size);
      /* If the real section is empty or there was a problem reading the
	 section we shouldn't get here.  */
      gdb_assert (containing_section->buffer != NULL);
      info->buffer = containing_section->buffer + info->virtual_offset;
      return;
    }

  /* If the section has relocations, we must read it ourselves.
     Otherwise we attach it to the BFD.  */
  if ((sectp->flags & SEC_RELOC) == 0)
    {
      info->buffer = gdb_bfd_map_section (sectp, &info->size);
      return;
    }

  buf = (gdb_byte *) obstack_alloc (&objfile->objfile_obstack, info->size);
  info->buffer = buf;

  /* When debugging .o files, we may need to apply relocations; see
     http://sourceware.org/ml/gdb-patches/2002-04/msg00136.html .
     We never compress sections in .o files, so we only need to
     try this when the section is not compressed.  */
  retbuf = symfile_relocate_debug_section (objfile, sectp, buf);
  if (retbuf != NULL)
    {
      info->buffer = retbuf;
      return;
    }

  abfd = get_section_bfd_owner (info);
  gdb_assert (abfd != NULL);

  if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
      || bfd_bread (buf, info->size, abfd) != info->size)
    {
      error (_("Dwarf Error: Can't read DWARF data"
	       " in section %s [in module %s]"),
	     bfd_section_name (sectp), bfd_get_filename (abfd));
    }
}

/* A helper function that returns the size of a section in a safe way.
   If you are positive that the section has been read before using the
   size, then it is safe to refer to the dwarf2_section_info object's
   "size" field directly.  In other cases, you must call this
   function, because for compressed sections the size field is not set
   correctly until the section has been read.  */

static bfd_size_type
dwarf2_section_size (struct objfile *objfile,
		     struct dwarf2_section_info *info)
{
  if (!info->readin)
    dwarf2_read_section (objfile, info);
  return info->size;
}

/* Fill in SECTP, BUFP and SIZEP with section info, given OBJFILE and
   SECTION_NAME.  */

void
dwarf2_get_section_info (struct objfile *objfile,
                         enum dwarf2_section_enum sect,
                         asection **sectp, const gdb_byte **bufp,
                         bfd_size_type *sizep)
{
  struct dwarf2_per_objfile *data = dwarf2_objfile_data_key.get (objfile);
  struct dwarf2_section_info *info;

  /* We may see an objfile without any DWARF, in which case we just
     return nothing.  */
  if (data == NULL)
    {
      *sectp = NULL;
      *bufp = NULL;
      *sizep = 0;
      return;
    }
  switch (sect)
    {
    case DWARF2_DEBUG_FRAME:
      info = &data->frame;
      break;
    case DWARF2_EH_FRAME:
      info = &data->eh_frame;
      break;
    default:
      gdb_assert_not_reached ("unexpected section");
    }

  dwarf2_read_section (objfile, info);

  *sectp = get_section_bfd_section (info);
  *bufp = info->buffer;
  *sizep = info->size;
}

/* A helper function to find the sections for a .dwz file.  */

static void
locate_dwz_sections (bfd *abfd, asection *sectp, void *arg)
{
  struct dwz_file *dwz_file = (struct dwz_file *) arg;

  /* Note that we only support the standard ELF names, because .dwz
     is ELF-only (at the time of writing).  */
  if (section_is_p (sectp->name, &dwarf2_elf_names.abbrev))
    {
      dwz_file->abbrev.s.section = sectp;
      dwz_file->abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.info))
    {
      dwz_file->info.s.section = sectp;
      dwz_file->info.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.str))
    {
      dwz_file->str.s.section = sectp;
      dwz_file->str.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.line))
    {
      dwz_file->line.s.section = sectp;
      dwz_file->line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.macro))
    {
      dwz_file->macro.s.section = sectp;
      dwz_file->macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.gdb_index))
    {
      dwz_file->gdb_index.s.section = sectp;
      dwz_file->gdb_index.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &dwarf2_elf_names.debug_names))
    {
      dwz_file->debug_names.s.section = sectp;
      dwz_file->debug_names.size = bfd_section_size (sectp);
    }
}

/* See dwarf2read.h.  */

struct dwz_file *
dwarf2_get_dwz_file (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  const char *filename;
  bfd_size_type buildid_len_arg;
  size_t buildid_len;
  bfd_byte *buildid;

  if (dwarf2_per_objfile->dwz_file != NULL)
    return dwarf2_per_objfile->dwz_file.get ();

  bfd_set_error (bfd_error_no_error);
  gdb::unique_xmalloc_ptr<char> data
    (bfd_get_alt_debug_link_info (dwarf2_per_objfile->objfile->obfd,
				  &buildid_len_arg, &buildid));
  if (data == NULL)
    {
      if (bfd_get_error () == bfd_error_no_error)
	return NULL;
      error (_("could not read '.gnu_debugaltlink' section: %s"),
	     bfd_errmsg (bfd_get_error ()));
    }

  gdb::unique_xmalloc_ptr<bfd_byte> buildid_holder (buildid);

  buildid_len = (size_t) buildid_len_arg;

  filename = data.get ();

  std::string abs_storage;
  if (!IS_ABSOLUTE_PATH (filename))
    {
      gdb::unique_xmalloc_ptr<char> abs
	= gdb_realpath (objfile_name (dwarf2_per_objfile->objfile));

      abs_storage = ldirname (abs.get ()) + SLASH_STRING + filename;
      filename = abs_storage.c_str ();
    }

  /* First try the file name given in the section.  If that doesn't
     work, try to use the build-id instead.  */
  gdb_bfd_ref_ptr dwz_bfd (gdb_bfd_open (filename, gnutarget, -1));
  if (dwz_bfd != NULL)
    {
      if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
	dwz_bfd.reset (nullptr);
    }

  if (dwz_bfd == NULL)
    dwz_bfd = build_id_to_debug_bfd (buildid_len, buildid);

  if (dwz_bfd == NULL)
    error (_("could not find '.gnu_debugaltlink' file for %s"),
	   objfile_name (dwarf2_per_objfile->objfile));

  std::unique_ptr<struct dwz_file> result
    (new struct dwz_file (std::move (dwz_bfd)));

  bfd_map_over_sections (result->dwz_bfd.get (), locate_dwz_sections,
			 result.get ());

  gdb_bfd_record_inclusion (dwarf2_per_objfile->objfile->obfd,
			    result->dwz_bfd.get ());
  dwarf2_per_objfile->dwz_file = std::move (result);
  return dwarf2_per_objfile->dwz_file.get ();
}

/* DWARF quick_symbols_functions support.  */

/* TUs can share .debug_line entries, and there can be a lot more TUs than
   unique line tables, so we maintain a separate table of all .debug_line
   derived entries to support the sharing.
   All the quick functions need is the list of file names.  We discard the
   line_header when we're done and don't need to record it here.  */
struct quick_file_names
{
  /* The data used to construct the hash key.  */
  struct stmt_list_hash hash;

  /* The number of entries in file_names, real_names.  */
  unsigned int num_file_names;

  /* The file names from the line table, after being run through
     file_full_name.  */
  const char **file_names;

  /* The file names from the line table after being run through
     gdb_realpath.  These are computed lazily.  */
  const char **real_names;
};

/* When using the index (and thus not using psymtabs), each CU has an
   object of this type.  This is used to hold information needed by
   the various "quick" methods.  */
struct dwarf2_per_cu_quick_data
{
  /* The file table.  This can be NULL if there was no file table
     or it's currently not read in.
     NOTE: This points into dwarf2_per_objfile->quick_file_names_table.  */
  struct quick_file_names *file_names;

  /* The corresponding symbol table.  This is NULL if symbols for this
     CU have not yet been read.  */
  struct compunit_symtab *compunit_symtab;

  /* A temporary mark bit used when iterating over all CUs in
     expand_symtabs_matching.  */
  unsigned int mark : 1;

  /* True if we've tried to read the file table and found there isn't one.
     There will be no point in trying to read it again next time.  */
  unsigned int no_file_data : 1;
};

/* Utility hash function for a stmt_list_hash.  */

static hashval_t
hash_stmt_list_entry (const struct stmt_list_hash *stmt_list_hash)
{
  hashval_t v = 0;

  if (stmt_list_hash->dwo_unit != NULL)
    v += (uintptr_t) stmt_list_hash->dwo_unit->dwo_file;
  v += to_underlying (stmt_list_hash->line_sect_off);
  return v;
}

/* Utility equality function for a stmt_list_hash.  */

static int
eq_stmt_list_entry (const struct stmt_list_hash *lhs,
		    const struct stmt_list_hash *rhs)
{
  if ((lhs->dwo_unit != NULL) != (rhs->dwo_unit != NULL))
    return 0;
  if (lhs->dwo_unit != NULL
      && lhs->dwo_unit->dwo_file != rhs->dwo_unit->dwo_file)
    return 0;

  return lhs->line_sect_off == rhs->line_sect_off;
}

/* Hash function for a quick_file_names.  */

static hashval_t
hash_file_name_entry (const void *e)
{
  const struct quick_file_names *file_data
    = (const struct quick_file_names *) e;

  return hash_stmt_list_entry (&file_data->hash);
}

/* Equality function for a quick_file_names.  */

static int
eq_file_name_entry (const void *a, const void *b)
{
  const struct quick_file_names *ea = (const struct quick_file_names *) a;
  const struct quick_file_names *eb = (const struct quick_file_names *) b;

  return eq_stmt_list_entry (&ea->hash, &eb->hash);
}

/* Delete function for a quick_file_names.  */

static void
delete_file_name_entry (void *e)
{
  struct quick_file_names *file_data = (struct quick_file_names *) e;
  int i;

  for (i = 0; i < file_data->num_file_names; ++i)
    {
      xfree ((void*) file_data->file_names[i]);
      if (file_data->real_names)
	xfree ((void*) file_data->real_names[i]);
    }

  /* The space for the struct itself lives on objfile_obstack,
     so we don't free it here.  */
}

/* Create a quick_file_names hash table.  */

static htab_t
create_quick_file_names_table (unsigned int nr_initial_entries)
{
  return htab_create_alloc (nr_initial_entries,
			    hash_file_name_entry, eq_file_name_entry,
			    delete_file_name_entry, xcalloc, xfree);
}

/* Read in PER_CU->CU.  This function is unrelated to symtabs, symtab would
   have to be created afterwards.  You should call age_cached_comp_units after
   processing PER_CU->CU.  dw2_setup must have been already called.  */

static void
load_cu (struct dwarf2_per_cu_data *per_cu, bool skip_partial)
{
  if (per_cu->is_debug_types)
    load_full_type_unit (per_cu);
  else
    load_full_comp_unit (per_cu, skip_partial, language_minimal);

  if (per_cu->cu == NULL)
    return;  /* Dummy CU.  */

  dwarf2_find_base_address (per_cu->cu->dies, per_cu->cu);
}

/* Read in the symbols for PER_CU.  */

static void
dw2_do_instantiate_symtab (struct dwarf2_per_cu_data *per_cu, bool skip_partial)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = per_cu->dwarf2_per_objfile;

  /* Skip type_unit_groups, reading the type units they contain
     is handled elsewhere.  */
  if (IS_TYPE_UNIT_GROUP (per_cu))
    return;

  /* The destructor of dwarf2_queue_guard frees any entries left on
     the queue.  After this point we're guaranteed to leave this function
     with the dwarf queue empty.  */
  dwarf2_queue_guard q_guard;

  if (dwarf2_per_objfile->using_index
      ? per_cu->v.quick->compunit_symtab == NULL
      : (per_cu->v.psymtab == NULL || !per_cu->v.psymtab->readin))
    {
      queue_comp_unit (per_cu, language_minimal);
      load_cu (per_cu, skip_partial);

      /* If we just loaded a CU from a DWO, and we're working with an index
	 that may badly handle TUs, load all the TUs in that DWO as well.
	 http://sourceware.org/bugzilla/show_bug.cgi?id=15021  */
      if (!per_cu->is_debug_types
	  && per_cu->cu != NULL
	  && per_cu->cu->dwo_unit != NULL
	  && dwarf2_per_objfile->index_table != NULL
	  && dwarf2_per_objfile->index_table->version <= 7
	  /* DWP files aren't supported yet.  */
	  && get_dwp_file (dwarf2_per_objfile) == NULL)
	queue_and_load_all_dwo_tus (per_cu);
    }

  process_queue (dwarf2_per_objfile);

  /* Age the cache, releasing compilation units that have not
     been used recently.  */
  age_cached_comp_units (dwarf2_per_objfile);
}

/* Ensure that the symbols for PER_CU have been read in.  OBJFILE is
   the objfile from which this CU came.  Returns the resulting symbol
   table.  */

static struct compunit_symtab *
dw2_instantiate_symtab (struct dwarf2_per_cu_data *per_cu, bool skip_partial)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = per_cu->dwarf2_per_objfile;

  gdb_assert (dwarf2_per_objfile->using_index);
  if (!per_cu->v.quick->compunit_symtab)
    {
      free_cached_comp_units freer (dwarf2_per_objfile);
      scoped_restore decrementer = increment_reading_symtab ();
      dw2_do_instantiate_symtab (per_cu, skip_partial);
      process_cu_includes (dwarf2_per_objfile);
    }

  return per_cu->v.quick->compunit_symtab;
}

/* See declaration.  */

dwarf2_per_cu_data *
dwarf2_per_objfile::get_cutu (int index)
{
  if (index >= this->all_comp_units.size ())
    {
      index -= this->all_comp_units.size ();
      gdb_assert (index < this->all_type_units.size ());
      return &this->all_type_units[index]->per_cu;
    }

  return this->all_comp_units[index];
}

/* See declaration.  */

dwarf2_per_cu_data *
dwarf2_per_objfile::get_cu (int index)
{
  gdb_assert (index >= 0 && index < this->all_comp_units.size ());

  return this->all_comp_units[index];
}

/* See declaration.  */

signatured_type *
dwarf2_per_objfile::get_tu (int index)
{
  gdb_assert (index >= 0 && index < this->all_type_units.size ());

  return this->all_type_units[index];
}

/* Return a new dwarf2_per_cu_data allocated on OBJFILE's
   objfile_obstack, and constructed with the specified field
   values.  */

static dwarf2_per_cu_data *
create_cu_from_index_list (struct dwarf2_per_objfile *dwarf2_per_objfile,
                          struct dwarf2_section_info *section,
                          int is_dwz,
                          sect_offset sect_off, ULONGEST length)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  dwarf2_per_cu_data *the_cu
    = OBSTACK_ZALLOC (&objfile->objfile_obstack,
                     struct dwarf2_per_cu_data);
  the_cu->sect_off = sect_off;
  the_cu->length = length;
  the_cu->dwarf2_per_objfile = dwarf2_per_objfile;
  the_cu->section = section;
  the_cu->v.quick = OBSTACK_ZALLOC (&objfile->objfile_obstack,
                                   struct dwarf2_per_cu_quick_data);
  the_cu->is_dwz = is_dwz;
  return the_cu;
}

/* A helper for create_cus_from_index that handles a given list of
   CUs.  */

static void
create_cus_from_index_list (struct dwarf2_per_objfile *dwarf2_per_objfile,
			    const gdb_byte *cu_list, offset_type n_elements,
			    struct dwarf2_section_info *section,
			    int is_dwz)
{
  for (offset_type i = 0; i < n_elements; i += 2)
    {
      gdb_static_assert (sizeof (ULONGEST) >= 8);

      sect_offset sect_off
	= (sect_offset) extract_unsigned_integer (cu_list, 8, BFD_ENDIAN_LITTLE);
      ULONGEST length = extract_unsigned_integer (cu_list + 8, 8, BFD_ENDIAN_LITTLE);
      cu_list += 2 * 8;

      dwarf2_per_cu_data *per_cu
	= create_cu_from_index_list (dwarf2_per_objfile, section, is_dwz,
				     sect_off, length);
      dwarf2_per_objfile->all_comp_units.push_back (per_cu);
    }
}

/* Read the CU list from the mapped index, and use it to create all
   the CU objects for this objfile.  */

static void
create_cus_from_index (struct dwarf2_per_objfile *dwarf2_per_objfile,
		       const gdb_byte *cu_list, offset_type cu_list_elements,
		       const gdb_byte *dwz_list, offset_type dwz_elements)
{
  gdb_assert (dwarf2_per_objfile->all_comp_units.empty ());
  dwarf2_per_objfile->all_comp_units.reserve
    ((cu_list_elements + dwz_elements) / 2);

  create_cus_from_index_list (dwarf2_per_objfile, cu_list, cu_list_elements,
			      &dwarf2_per_objfile->info, 0);

  if (dwz_elements == 0)
    return;

  dwz_file *dwz = dwarf2_get_dwz_file (dwarf2_per_objfile);
  create_cus_from_index_list (dwarf2_per_objfile, dwz_list, dwz_elements,
			      &dwz->info, 1);
}

/* Create the signatured type hash table from the index.  */

static void
create_signatured_type_table_from_index
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   struct dwarf2_section_info *section,
   const gdb_byte *bytes,
   offset_type elements)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  gdb_assert (dwarf2_per_objfile->all_type_units.empty ());
  dwarf2_per_objfile->all_type_units.reserve (elements / 3);

  htab_t sig_types_hash = allocate_signatured_type_table (objfile);

  for (offset_type i = 0; i < elements; i += 3)
    {
      struct signatured_type *sig_type;
      ULONGEST signature;
      void **slot;
      cu_offset type_offset_in_tu;

      gdb_static_assert (sizeof (ULONGEST) >= 8);
      sect_offset sect_off
	= (sect_offset) extract_unsigned_integer (bytes, 8, BFD_ENDIAN_LITTLE);
      type_offset_in_tu
	= (cu_offset) extract_unsigned_integer (bytes + 8, 8,
						BFD_ENDIAN_LITTLE);
      signature = extract_unsigned_integer (bytes + 16, 8, BFD_ENDIAN_LITTLE);
      bytes += 3 * 8;

      sig_type = OBSTACK_ZALLOC (&objfile->objfile_obstack,
				 struct signatured_type);
      sig_type->signature = signature;
      sig_type->type_offset_in_tu = type_offset_in_tu;
      sig_type->per_cu.is_debug_types = 1;
      sig_type->per_cu.section = section;
      sig_type->per_cu.sect_off = sect_off;
      sig_type->per_cu.dwarf2_per_objfile = dwarf2_per_objfile;
      sig_type->per_cu.v.quick
	= OBSTACK_ZALLOC (&objfile->objfile_obstack,
			  struct dwarf2_per_cu_quick_data);

      slot = htab_find_slot (sig_types_hash, sig_type, INSERT);
      *slot = sig_type;

      dwarf2_per_objfile->all_type_units.push_back (sig_type);
    }

  dwarf2_per_objfile->signatured_types = sig_types_hash;
}

/* Create the signatured type hash table from .debug_names.  */

static void
create_signatured_type_table_from_debug_names
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   const mapped_debug_names &map,
   struct dwarf2_section_info *section,
   struct dwarf2_section_info *abbrev_section)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  dwarf2_read_section (objfile, section);
  dwarf2_read_section (objfile, abbrev_section);

  gdb_assert (dwarf2_per_objfile->all_type_units.empty ());
  dwarf2_per_objfile->all_type_units.reserve (map.tu_count);

  htab_t sig_types_hash = allocate_signatured_type_table (objfile);

  for (uint32_t i = 0; i < map.tu_count; ++i)
    {
      struct signatured_type *sig_type;
      void **slot;

      sect_offset sect_off
	= (sect_offset) (extract_unsigned_integer
			 (map.tu_table_reordered + i * map.offset_size,
			  map.offset_size,
			  map.dwarf5_byte_order));

      comp_unit_head cu_header;
      read_and_check_comp_unit_head (dwarf2_per_objfile, &cu_header, section,
				     abbrev_section,
				     section->buffer + to_underlying (sect_off),
				     rcuh_kind::TYPE);

      sig_type = OBSTACK_ZALLOC (&objfile->objfile_obstack,
				 struct signatured_type);
      sig_type->signature = cu_header.signature;
      sig_type->type_offset_in_tu = cu_header.type_cu_offset_in_tu;
      sig_type->per_cu.is_debug_types = 1;
      sig_type->per_cu.section = section;
      sig_type->per_cu.sect_off = sect_off;
      sig_type->per_cu.dwarf2_per_objfile = dwarf2_per_objfile;
      sig_type->per_cu.v.quick
	= OBSTACK_ZALLOC (&objfile->objfile_obstack,
			  struct dwarf2_per_cu_quick_data);

      slot = htab_find_slot (sig_types_hash, sig_type, INSERT);
      *slot = sig_type;

      dwarf2_per_objfile->all_type_units.push_back (sig_type);
    }

  dwarf2_per_objfile->signatured_types = sig_types_hash;
}

/* Read the address map data from the mapped index, and use it to
   populate the objfile's psymtabs_addrmap.  */

static void
create_addrmap_from_index (struct dwarf2_per_objfile *dwarf2_per_objfile,
			   struct mapped_index *index)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  const gdb_byte *iter, *end;
  struct addrmap *mutable_map;
  CORE_ADDR baseaddr;

  auto_obstack temp_obstack;

  mutable_map = addrmap_create_mutable (&temp_obstack);

  iter = index->address_table.data ();
  end = iter + index->address_table.size ();

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  while (iter < end)
    {
      ULONGEST hi, lo, cu_index;
      lo = extract_unsigned_integer (iter, 8, BFD_ENDIAN_LITTLE);
      iter += 8;
      hi = extract_unsigned_integer (iter, 8, BFD_ENDIAN_LITTLE);
      iter += 8;
      cu_index = extract_unsigned_integer (iter, 4, BFD_ENDIAN_LITTLE);
      iter += 4;

      if (lo > hi)
	{
	  complaint (_(".gdb_index address table has invalid range (%s - %s)"),
		     hex_string (lo), hex_string (hi));
	  continue;
	}

      if (cu_index >= dwarf2_per_objfile->all_comp_units.size ())
	{
	  complaint (_(".gdb_index address table has invalid CU number %u"),
		     (unsigned) cu_index);
	  continue;
	}

      lo = gdbarch_adjust_dwarf2_addr (gdbarch, lo + baseaddr) - baseaddr;
      hi = gdbarch_adjust_dwarf2_addr (gdbarch, hi + baseaddr) - baseaddr;
      addrmap_set_empty (mutable_map, lo, hi - 1,
			 dwarf2_per_objfile->get_cu (cu_index));
    }

  objfile->partial_symtabs->psymtabs_addrmap
    = addrmap_create_fixed (mutable_map, objfile->partial_symtabs->obstack ());
}

/* Read the address map data from DWARF-5 .debug_aranges, and use it to
   populate the objfile's psymtabs_addrmap.  */

static void
create_addrmap_from_aranges (struct dwarf2_per_objfile *dwarf2_per_objfile,
			     struct dwarf2_section_info *section)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  bfd *abfd = objfile->obfd;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  const CORE_ADDR baseaddr = ANOFFSET (objfile->section_offsets,
				       SECT_OFF_TEXT (objfile));

  auto_obstack temp_obstack;
  addrmap *mutable_map = addrmap_create_mutable (&temp_obstack);

  std::unordered_map<sect_offset,
		     dwarf2_per_cu_data *,
		     gdb::hash_enum<sect_offset>>
    debug_info_offset_to_per_cu;
  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      const auto insertpair
	= debug_info_offset_to_per_cu.emplace (per_cu->sect_off, per_cu);
      if (!insertpair.second)
	{
	  warning (_("Section .debug_aranges in %s has duplicate "
		     "debug_info_offset %s, ignoring .debug_aranges."),
		   objfile_name (objfile), sect_offset_str (per_cu->sect_off));
	  return;
	}
    }

  dwarf2_read_section (objfile, section);

  const bfd_endian dwarf5_byte_order = gdbarch_byte_order (gdbarch);

  const gdb_byte *addr = section->buffer;

  while (addr < section->buffer + section->size)
    {
      const gdb_byte *const entry_addr = addr;
      unsigned int bytes_read;

      const LONGEST entry_length = read_initial_length (abfd, addr,
							&bytes_read);
      addr += bytes_read;

      const gdb_byte *const entry_end = addr + entry_length;
      const bool dwarf5_is_dwarf64 = bytes_read != 4;
      const uint8_t offset_size = dwarf5_is_dwarf64 ? 8 : 4;
      if (addr + entry_length > section->buffer + section->size)
	{
	  warning (_("Section .debug_aranges in %s entry at offset %s "
	             "length %s exceeds section length %s, "
		     "ignoring .debug_aranges."),
		   objfile_name (objfile),
		   plongest (entry_addr - section->buffer),
		   plongest (bytes_read + entry_length),
		   pulongest (section->size));
	  return;
	}

      /* The version number.  */
      const uint16_t version = read_2_bytes (abfd, addr);
      addr += 2;
      if (version != 2)
	{
	  warning (_("Section .debug_aranges in %s entry at offset %s "
		     "has unsupported version %d, ignoring .debug_aranges."),
		   objfile_name (objfile),
		   plongest (entry_addr - section->buffer), version);
	  return;
	}

      const uint64_t debug_info_offset
	= extract_unsigned_integer (addr, offset_size, dwarf5_byte_order);
      addr += offset_size;
      const auto per_cu_it
	= debug_info_offset_to_per_cu.find (sect_offset (debug_info_offset));
      if (per_cu_it == debug_info_offset_to_per_cu.cend ())
	{
	  warning (_("Section .debug_aranges in %s entry at offset %s "
		     "debug_info_offset %s does not exists, "
		     "ignoring .debug_aranges."),
		   objfile_name (objfile),
		   plongest (entry_addr - section->buffer),
		   pulongest (debug_info_offset));
	  return;
	}
      dwarf2_per_cu_data *const per_cu = per_cu_it->second;

      const uint8_t address_size = *addr++;
      if (address_size < 1 || address_size > 8)
	{
	  warning (_("Section .debug_aranges in %s entry at offset %s "
		     "address_size %u is invalid, ignoring .debug_aranges."),
		   objfile_name (objfile),
		   plongest (entry_addr - section->buffer), address_size);
	  return;
	}

      const uint8_t segment_selector_size = *addr++;
      if (segment_selector_size != 0)
	{
	  warning (_("Section .debug_aranges in %s entry at offset %s "
		     "segment_selector_size %u is not supported, "
		     "ignoring .debug_aranges."),
		   objfile_name (objfile),
		   plongest (entry_addr - section->buffer),
		   segment_selector_size);
	  return;
	}

      /* Must pad to an alignment boundary that is twice the address
         size.  It is undocumented by the DWARF standard but GCC does
         use it.  */
      for (size_t padding = ((-(addr - section->buffer))
			     & (2 * address_size - 1));
           padding > 0; padding--)
	if (*addr++ != 0)
	  {
	    warning (_("Section .debug_aranges in %s entry at offset %s "
		       "padding is not zero, ignoring .debug_aranges."),
		     objfile_name (objfile),
		     plongest (entry_addr - section->buffer));
	    return;
	  }

      for (;;)
	{
	  if (addr + 2 * address_size > entry_end)
	    {
	      warning (_("Section .debug_aranges in %s entry at offset %s "
			 "address list is not properly terminated, "
			 "ignoring .debug_aranges."),
		       objfile_name (objfile),
		       plongest (entry_addr - section->buffer));
	      return;
	    }
	  ULONGEST start = extract_unsigned_integer (addr, address_size,
						     dwarf5_byte_order);
	  addr += address_size;
	  ULONGEST length = extract_unsigned_integer (addr, address_size,
						      dwarf5_byte_order);
	  addr += address_size;
	  if (start == 0 && length == 0)
	    break;
	  if (start == 0 && !dwarf2_per_objfile->has_section_at_zero)
	    {
	      /* Symbol was eliminated due to a COMDAT group.  */
	      continue;
	    }
	  ULONGEST end = start + length;
	  start = (gdbarch_adjust_dwarf2_addr (gdbarch, start + baseaddr)
		   - baseaddr);
	  end = (gdbarch_adjust_dwarf2_addr (gdbarch, end + baseaddr)
		 - baseaddr);
	  addrmap_set_empty (mutable_map, start, end - 1, per_cu);
	}
    }

  objfile->partial_symtabs->psymtabs_addrmap
    = addrmap_create_fixed (mutable_map, objfile->partial_symtabs->obstack ());
}

/* Find a slot in the mapped index INDEX for the object named NAME.
   If NAME is found, set *VEC_OUT to point to the CU vector in the
   constant pool and return true.  If NAME cannot be found, return
   false.  */

static bool
find_slot_in_mapped_hash (struct mapped_index *index, const char *name,
			  offset_type **vec_out)
{
  offset_type hash;
  offset_type slot, step;
  int (*cmp) (const char *, const char *);

  gdb::unique_xmalloc_ptr<char> without_params;
  if (current_language->la_language == language_cplus
      || current_language->la_language == language_fortran
      || current_language->la_language == language_d)
    {
      /* NAME is already canonical.  Drop any qualifiers as .gdb_index does
	 not contain any.  */

      if (strchr (name, '(') != NULL)
	{
	  without_params = cp_remove_params (name);

	  if (without_params != NULL)
	    name = without_params.get ();
	}
    }

  /* Index version 4 did not support case insensitive searches.  But the
     indices for case insensitive languages are built in lowercase, therefore
     simulate our NAME being searched is also lowercased.  */
  hash = mapped_index_string_hash ((index->version == 4
                                    && case_sensitivity == case_sensitive_off
				    ? 5 : index->version),
				   name);

  slot = hash & (index->symbol_table.size () - 1);
  step = ((hash * 17) & (index->symbol_table.size () - 1)) | 1;
  cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);

  for (;;)
    {
      const char *str;

      const auto &bucket = index->symbol_table[slot];
      if (bucket.name == 0 && bucket.vec == 0)
	return false;

      str = index->constant_pool + MAYBE_SWAP (bucket.name);
      if (!cmp (name, str))
	{
	  *vec_out = (offset_type *) (index->constant_pool
				      + MAYBE_SWAP (bucket.vec));
	  return true;
	}

      slot = (slot + step) & (index->symbol_table.size () - 1);
    }
}

/* A helper function that reads the .gdb_index from BUFFER and fills
   in MAP.  FILENAME is the name of the file containing the data;
   it is used for error reporting.  DEPRECATED_OK is true if it is
   ok to use deprecated sections.

   CU_LIST, CU_LIST_ELEMENTS, TYPES_LIST, and TYPES_LIST_ELEMENTS are
   out parameters that are filled in with information about the CU and
   TU lists in the section.

   Returns true if all went well, false otherwise.  */

static bool
read_gdb_index_from_buffer (struct objfile *objfile,
			    const char *filename,
			    bool deprecated_ok,
			    gdb::array_view<const gdb_byte> buffer,
			    struct mapped_index *map,
			    const gdb_byte **cu_list,
			    offset_type *cu_list_elements,
			    const gdb_byte **types_list,
			    offset_type *types_list_elements)
{
  const gdb_byte *addr = &buffer[0];

  /* Version check.  */
  offset_type version = MAYBE_SWAP (*(offset_type *) addr);
  /* Versions earlier than 3 emitted every copy of a psymbol.  This
     causes the index to behave very poorly for certain requests.  Version 3
     contained incomplete addrmap.  So, it seems better to just ignore such
     indices.  */
  if (version < 4)
    {
      static int warning_printed = 0;
      if (!warning_printed)
	{
	  warning (_("Skipping obsolete .gdb_index section in %s."),
		   filename);
	  warning_printed = 1;
	}
      return 0;
    }
  /* Index version 4 uses a different hash function than index version
     5 and later.

     Versions earlier than 6 did not emit psymbols for inlined
     functions.  Using these files will cause GDB not to be able to
     set breakpoints on inlined functions by name, so we ignore these
     indices unless the user has done
     "set use-deprecated-index-sections on".  */
  if (version < 6 && !deprecated_ok)
    {
      static int warning_printed = 0;
      if (!warning_printed)
	{
	  warning (_("\
Skipping deprecated .gdb_index section in %s.\n\
Do \"set use-deprecated-index-sections on\" before the file is read\n\
to use the section anyway."),
		   filename);
	  warning_printed = 1;
	}
      return 0;
    }
  /* Version 7 indices generated by gold refer to the CU for a symbol instead
     of the TU (for symbols coming from TUs),
     http://sourceware.org/bugzilla/show_bug.cgi?id=15021.
     Plus gold-generated indices can have duplicate entries for global symbols,
     http://sourceware.org/bugzilla/show_bug.cgi?id=15646.
     These are just performance bugs, and we can't distinguish gdb-generated
     indices from gold-generated ones, so issue no warning here.  */

  /* Indexes with higher version than the one supported by GDB may be no
     longer backward compatible.  */
  if (version > 8)
    return 0;

  map->version = version;

  offset_type *metadata = (offset_type *) (addr + sizeof (offset_type));

  int i = 0;
  *cu_list = addr + MAYBE_SWAP (metadata[i]);
  *cu_list_elements = ((MAYBE_SWAP (metadata[i + 1]) - MAYBE_SWAP (metadata[i]))
		       / 8);
  ++i;

  *types_list = addr + MAYBE_SWAP (metadata[i]);
  *types_list_elements = ((MAYBE_SWAP (metadata[i + 1])
			   - MAYBE_SWAP (metadata[i]))
			  / 8);
  ++i;

  const gdb_byte *address_table = addr + MAYBE_SWAP (metadata[i]);
  const gdb_byte *address_table_end = addr + MAYBE_SWAP (metadata[i + 1]);
  map->address_table
    = gdb::array_view<const gdb_byte> (address_table, address_table_end);
  ++i;

  const gdb_byte *symbol_table = addr + MAYBE_SWAP (metadata[i]);
  const gdb_byte *symbol_table_end = addr + MAYBE_SWAP (metadata[i + 1]);
  map->symbol_table
    = gdb::array_view<mapped_index::symbol_table_slot>
       ((mapped_index::symbol_table_slot *) symbol_table,
	(mapped_index::symbol_table_slot *) symbol_table_end);

  ++i;
  map->constant_pool = (char *) (addr + MAYBE_SWAP (metadata[i]));

  return 1;
}

/* Callback types for dwarf2_read_gdb_index.  */

typedef gdb::function_view
    <gdb::array_view<const gdb_byte>(objfile *, dwarf2_per_objfile *)>
    get_gdb_index_contents_ftype;
typedef gdb::function_view
    <gdb::array_view<const gdb_byte>(objfile *, dwz_file *)>
    get_gdb_index_contents_dwz_ftype;

/* Read .gdb_index.  If everything went ok, initialize the "quick"
   elements of all the CUs and return 1.  Otherwise, return 0.  */

static int
dwarf2_read_gdb_index
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   get_gdb_index_contents_ftype get_gdb_index_contents,
   get_gdb_index_contents_dwz_ftype get_gdb_index_contents_dwz)
{
  const gdb_byte *cu_list, *types_list, *dwz_list = NULL;
  offset_type cu_list_elements, types_list_elements, dwz_list_elements = 0;
  struct dwz_file *dwz;
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  gdb::array_view<const gdb_byte> main_index_contents
    = get_gdb_index_contents (objfile, dwarf2_per_objfile);

  if (main_index_contents.empty ())
    return 0;

  std::unique_ptr<struct mapped_index> map (new struct mapped_index);
  if (!read_gdb_index_from_buffer (objfile, objfile_name (objfile),
				   use_deprecated_index_sections,
				   main_index_contents, map.get (), &cu_list,
				   &cu_list_elements, &types_list,
				   &types_list_elements))
    return 0;

  /* Don't use the index if it's empty.  */
  if (map->symbol_table.empty ())
    return 0;

  /* If there is a .dwz file, read it so we can get its CU list as
     well.  */
  dwz = dwarf2_get_dwz_file (dwarf2_per_objfile);
  if (dwz != NULL)
    {
      struct mapped_index dwz_map;
      const gdb_byte *dwz_types_ignore;
      offset_type dwz_types_elements_ignore;

      gdb::array_view<const gdb_byte> dwz_index_content
	= get_gdb_index_contents_dwz (objfile, dwz);

      if (dwz_index_content.empty ())
	return 0;

      if (!read_gdb_index_from_buffer (objfile,
				       bfd_get_filename (dwz->dwz_bfd.get ()),
				       1, dwz_index_content, &dwz_map,
				       &dwz_list, &dwz_list_elements,
				       &dwz_types_ignore,
				       &dwz_types_elements_ignore))
	{
	  warning (_("could not read '.gdb_index' section from %s; skipping"),
		   bfd_get_filename (dwz->dwz_bfd.get ()));
	  return 0;
	}
    }

  create_cus_from_index (dwarf2_per_objfile, cu_list, cu_list_elements,
			 dwz_list, dwz_list_elements);

  if (types_list_elements)
    {
      /* We can only handle a single .debug_types when we have an
	 index.  */
      if (dwarf2_per_objfile->types.size () != 1)
	return 0;

      dwarf2_section_info *section = &dwarf2_per_objfile->types[0];

      create_signatured_type_table_from_index (dwarf2_per_objfile, section,
					       types_list, types_list_elements);
    }

  create_addrmap_from_index (dwarf2_per_objfile, map.get ());

  dwarf2_per_objfile->index_table = std::move (map);
  dwarf2_per_objfile->using_index = 1;
  dwarf2_per_objfile->quick_file_names_table =
    create_quick_file_names_table (dwarf2_per_objfile->all_comp_units.size ());

  return 1;
}

/* die_reader_func for dw2_get_file_names.  */

static void
dw2_get_file_names_reader (const struct die_reader_specs *reader,
			   const gdb_byte *info_ptr,
			   struct die_info *comp_unit_die,
			   int has_children,
			   void *data)
{
  struct dwarf2_cu *cu = reader->cu;
  struct dwarf2_per_cu_data *this_cu = cu->per_cu;
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_per_cu_data *lh_cu;
  struct attribute *attr;
  void **slot;
  struct quick_file_names *qfn;

  gdb_assert (! this_cu->is_debug_types);

  /* Our callers never want to match partial units -- instead they
     will match the enclosing full CU.  */
  if (comp_unit_die->tag == DW_TAG_partial_unit)
    {
      this_cu->v.quick->no_file_data = 1;
      return;
    }

  lh_cu = this_cu;
  slot = NULL;

  line_header_up lh;
  sect_offset line_offset {};

  attr = dwarf2_attr (comp_unit_die, DW_AT_stmt_list, cu);
  if (attr != nullptr)
    {
      struct quick_file_names find_entry;

      line_offset = (sect_offset) DW_UNSND (attr);

      /* We may have already read in this line header (TU line header sharing).
	 If we have we're done.  */
      find_entry.hash.dwo_unit = cu->dwo_unit;
      find_entry.hash.line_sect_off = line_offset;
      slot = htab_find_slot (dwarf2_per_objfile->quick_file_names_table,
			     &find_entry, INSERT);
      if (*slot != NULL)
	{
	  lh_cu->v.quick->file_names = (struct quick_file_names *) *slot;
	  return;
	}

      lh = dwarf_decode_line_header (line_offset, cu);
    }
  if (lh == NULL)
    {
      lh_cu->v.quick->no_file_data = 1;
      return;
    }

  qfn = XOBNEW (&objfile->objfile_obstack, struct quick_file_names);
  qfn->hash.dwo_unit = cu->dwo_unit;
  qfn->hash.line_sect_off = line_offset;
  gdb_assert (slot != NULL);
  *slot = qfn;

  file_and_directory fnd = find_file_and_directory (comp_unit_die, cu);

  int offset = 0;
  if (strcmp (fnd.name, "<unknown>") != 0)
    ++offset;

  qfn->num_file_names = offset + lh->file_names_size ();
  qfn->file_names =
    XOBNEWVEC (&objfile->objfile_obstack, const char *, qfn->num_file_names);
  if (offset != 0)
    qfn->file_names[0] = xstrdup (fnd.name);
  if (lh->version >= 5) {
    for (int i = 0; i < lh->file_names_size (); ++i)
      qfn->file_names[i + offset] = file_full_name (i, lh.get (), fnd.comp_dir);
  } else {
    for (int i = 0; i < lh->file_names_size (); ++i)
      qfn->file_names[i + offset] = file_full_name (i + 1, lh.get (),
						    fnd.comp_dir);
  }
  qfn->real_names = NULL;

  lh_cu->v.quick->file_names = qfn;
}

/* A helper for the "quick" functions which attempts to read the line
   table for THIS_CU.  */

static struct quick_file_names *
dw2_get_file_names (struct dwarf2_per_cu_data *this_cu)
{
  /* This should never be called for TUs.  */
  gdb_assert (! this_cu->is_debug_types);
  /* Nor type unit groups.  */
  gdb_assert (! IS_TYPE_UNIT_GROUP (this_cu));

  if (this_cu->v.quick->file_names != NULL)
    return this_cu->v.quick->file_names;
  /* If we know there is no line data, no point in looking again.  */
  if (this_cu->v.quick->no_file_data)
    return NULL;

  init_cutu_and_read_dies_simple (this_cu, dw2_get_file_names_reader, NULL);

  if (this_cu->v.quick->no_file_data)
    return NULL;
  return this_cu->v.quick->file_names;
}

/* A helper for the "quick" functions which computes and caches the
   real path for a given file name from the line table.  */

static const char *
dw2_get_real_path (struct objfile *objfile,
		   struct quick_file_names *qfn, int index)
{
  if (qfn->real_names == NULL)
    qfn->real_names = OBSTACK_CALLOC (&objfile->objfile_obstack,
				      qfn->num_file_names, const char *);

  if (qfn->real_names[index] == NULL)
    qfn->real_names[index] = gdb_realpath (qfn->file_names[index]).release ();

  return qfn->real_names[index];
}

static struct symtab *
dw2_find_last_source_symtab (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);
  dwarf2_per_cu_data *dwarf_cu = dwarf2_per_objfile->all_comp_units.back ();
  compunit_symtab *cust = dw2_instantiate_symtab (dwarf_cu, false);

  if (cust == NULL)
    return NULL;

  return compunit_primary_filetab (cust);
}

/* Traversal function for dw2_forget_cached_source_info.  */

static int
dw2_free_cached_file_names (void **slot, void *info)
{
  struct quick_file_names *file_data = (struct quick_file_names *) *slot;

  if (file_data->real_names)
    {
      int i;

      for (i = 0; i < file_data->num_file_names; ++i)
	{
	  xfree ((void*) file_data->real_names[i]);
	  file_data->real_names[i] = NULL;
	}
    }

  return 1;
}

static void
dw2_forget_cached_source_info (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  htab_traverse_noresize (dwarf2_per_objfile->quick_file_names_table,
			  dw2_free_cached_file_names, NULL);
}

/* Helper function for dw2_map_symtabs_matching_filename that expands
   the symtabs and calls the iterator.  */

static int
dw2_map_expand_apply (struct objfile *objfile,
		      struct dwarf2_per_cu_data *per_cu,
		      const char *name, const char *real_path,
		      gdb::function_view<bool (symtab *)> callback)
{
  struct compunit_symtab *last_made = objfile->compunit_symtabs;

  /* Don't visit already-expanded CUs.  */
  if (per_cu->v.quick->compunit_symtab)
    return 0;

  /* This may expand more than one symtab, and we want to iterate over
     all of them.  */
  dw2_instantiate_symtab (per_cu, false);

  return iterate_over_some_symtabs (name, real_path, objfile->compunit_symtabs,
				    last_made, callback);
}

/* Implementation of the map_symtabs_matching_filename method.  */

static bool
dw2_map_symtabs_matching_filename
  (struct objfile *objfile, const char *name, const char *real_path,
   gdb::function_view<bool (symtab *)> callback)
{
  const char *name_basename = lbasename (name);
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* The rule is CUs specify all the files, including those used by
     any TU, so there's no need to scan TUs here.  */

  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      /* We only need to look at symtabs not already expanded.  */
      if (per_cu->v.quick->compunit_symtab)
	continue;

      quick_file_names *file_data = dw2_get_file_names (per_cu);
      if (file_data == NULL)
	continue;

      for (int j = 0; j < file_data->num_file_names; ++j)
	{
	  const char *this_name = file_data->file_names[j];
	  const char *this_real_name;

	  if (compare_filenames_for_search (this_name, name))
	    {
	      if (dw2_map_expand_apply (objfile, per_cu, name, real_path,
					callback))
		return true;
	      continue;
	    }

	  /* Before we invoke realpath, which can get expensive when many
	     files are involved, do a quick comparison of the basenames.  */
	  if (! basenames_may_differ
	      && FILENAME_CMP (lbasename (this_name), name_basename) != 0)
	    continue;

	  this_real_name = dw2_get_real_path (objfile, file_data, j);
	  if (compare_filenames_for_search (this_real_name, name))
	    {
	      if (dw2_map_expand_apply (objfile, per_cu, name, real_path,
					callback))
		return true;
	      continue;
	    }

	  if (real_path != NULL)
	    {
	      gdb_assert (IS_ABSOLUTE_PATH (real_path));
	      gdb_assert (IS_ABSOLUTE_PATH (name));
	      if (this_real_name != NULL
		  && FILENAME_CMP (real_path, this_real_name) == 0)
		{
		  if (dw2_map_expand_apply (objfile, per_cu, name, real_path,
					    callback))
		    return true;
		  continue;
		}
	    }
	}
    }

  return false;
}

/* Struct used to manage iterating over all CUs looking for a symbol.  */

struct dw2_symtab_iterator
{
  /* The dwarf2_per_objfile owning the CUs we are iterating on.  */
  struct dwarf2_per_objfile *dwarf2_per_objfile;
  /* If set, only look for symbols that match that block.  Valid values are
     GLOBAL_BLOCK and STATIC_BLOCK.  */
  gdb::optional<block_enum> block_index;
  /* The kind of symbol we're looking for.  */
  domain_enum domain;
  /* The list of CUs from the index entry of the symbol,
     or NULL if not found.  */
  offset_type *vec;
  /* The next element in VEC to look at.  */
  int next;
  /* The number of elements in VEC, or zero if there is no match.  */
  int length;
  /* Have we seen a global version of the symbol?
     If so we can ignore all further global instances.
     This is to work around gold/15646, inefficient gold-generated
     indices.  */
  int global_seen;
};

/* Initialize the index symtab iterator ITER.  */

static void
dw2_symtab_iter_init (struct dw2_symtab_iterator *iter,
		      struct dwarf2_per_objfile *dwarf2_per_objfile,
		      gdb::optional<block_enum> block_index,
		      domain_enum domain,
		      const char *name)
{
  iter->dwarf2_per_objfile = dwarf2_per_objfile;
  iter->block_index = block_index;
  iter->domain = domain;
  iter->next = 0;
  iter->global_seen = 0;

  mapped_index *index = dwarf2_per_objfile->index_table.get ();

  /* index is NULL if OBJF_READNOW.  */
  if (index != NULL && find_slot_in_mapped_hash (index, name, &iter->vec))
    iter->length = MAYBE_SWAP (*iter->vec);
  else
    {
      iter->vec = NULL;
      iter->length = 0;
    }
}

/* Return the next matching CU or NULL if there are no more.  */

static struct dwarf2_per_cu_data *
dw2_symtab_iter_next (struct dw2_symtab_iterator *iter)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = iter->dwarf2_per_objfile;

  for ( ; iter->next < iter->length; ++iter->next)
    {
      offset_type cu_index_and_attrs =
	MAYBE_SWAP (iter->vec[iter->next + 1]);
      offset_type cu_index = GDB_INDEX_CU_VALUE (cu_index_and_attrs);
      gdb_index_symbol_kind symbol_kind =
	GDB_INDEX_SYMBOL_KIND_VALUE (cu_index_and_attrs);
      /* Only check the symbol attributes if they're present.
	 Indices prior to version 7 don't record them,
	 and indices >= 7 may elide them for certain symbols
	 (gold does this).  */
      int attrs_valid =
	(dwarf2_per_objfile->index_table->version >= 7
	 && symbol_kind != GDB_INDEX_SYMBOL_KIND_NONE);

      /* Don't crash on bad data.  */
      if (cu_index >= (dwarf2_per_objfile->all_comp_units.size ()
		       + dwarf2_per_objfile->all_type_units.size ()))
	{
	  complaint (_(".gdb_index entry has bad CU index"
		       " [in module %s]"),
		     objfile_name (dwarf2_per_objfile->objfile));
	  continue;
	}

      dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (cu_index);

      /* Skip if already read in.  */
      if (per_cu->v.quick->compunit_symtab)
	continue;

      /* Check static vs global.  */
      if (attrs_valid)
	{
	  bool is_static = GDB_INDEX_SYMBOL_STATIC_VALUE (cu_index_and_attrs);

	  if (iter->block_index.has_value ())
	    {
	      bool want_static = *iter->block_index == STATIC_BLOCK;

	      if (is_static != want_static)
		continue;
	    }

	  /* Work around gold/15646.  */
	  if (!is_static && iter->global_seen)
	    continue;
	  if (!is_static)
	    iter->global_seen = 1;
	}

      /* Only check the symbol's kind if it has one.  */
      if (attrs_valid)
	{
	  switch (iter->domain)
	    {
	    case VAR_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_VARIABLE
		  && symbol_kind != GDB_INDEX_SYMBOL_KIND_FUNCTION
		  /* Some types are also in VAR_DOMAIN.  */
		  && symbol_kind != GDB_INDEX_SYMBOL_KIND_TYPE)
		continue;
	      break;
	    case STRUCT_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_TYPE)
		continue;
	      break;
	    case LABEL_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
		continue;
	      break;
	    case MODULE_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
		continue;
	      break;
	    default:
	      break;
	    }
	}

      ++iter->next;
      return per_cu;
    }

  return NULL;
}

static struct compunit_symtab *
dw2_lookup_symbol (struct objfile *objfile, block_enum block_index,
		   const char *name, domain_enum domain)
{
  struct compunit_symtab *stab_best = NULL;
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  lookup_name_info lookup_name (name, symbol_name_match_type::FULL);

  struct dw2_symtab_iterator iter;
  struct dwarf2_per_cu_data *per_cu;

  dw2_symtab_iter_init (&iter, dwarf2_per_objfile, block_index, domain, name);

  while ((per_cu = dw2_symtab_iter_next (&iter)) != NULL)
    {
      struct symbol *sym, *with_opaque = NULL;
      struct compunit_symtab *stab = dw2_instantiate_symtab (per_cu, false);
      const struct blockvector *bv = COMPUNIT_BLOCKVECTOR (stab);
      const struct block *block = BLOCKVECTOR_BLOCK (bv, block_index);

      sym = block_find_symbol (block, name, domain,
			       block_find_non_opaque_type_preferred,
			       &with_opaque);

      /* Some caution must be observed with overloaded functions
	 and methods, since the index will not contain any overload
	 information (but NAME might contain it).  */

      if (sym != NULL
	  && SYMBOL_MATCHES_SEARCH_NAME (sym, lookup_name))
	return stab;
      if (with_opaque != NULL
	  && SYMBOL_MATCHES_SEARCH_NAME (with_opaque, lookup_name))
	stab_best = stab;

      /* Keep looking through other CUs.  */
    }

  return stab_best;
}

static void
dw2_print_stats (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);
  int total = (dwarf2_per_objfile->all_comp_units.size ()
	       + dwarf2_per_objfile->all_type_units.size ());
  int count = 0;

  for (int i = 0; i < total; ++i)
    {
      dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (i);

      if (!per_cu->v.quick->compunit_symtab)
	++count;
    }
  printf_filtered (_("  Number of read CUs: %d\n"), total - count);
  printf_filtered (_("  Number of unread CUs: %d\n"), count);
}

/* This dumps minimal information about the index.
   It is called via "mt print objfiles".
   One use is to verify .gdb_index has been loaded by the
   gdb.dwarf2/gdb-index.exp testcase.  */

static void
dw2_dump (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  gdb_assert (dwarf2_per_objfile->using_index);
  printf_filtered (".gdb_index:");
  if (dwarf2_per_objfile->index_table != NULL)
    {
      printf_filtered (" version %d\n",
		       dwarf2_per_objfile->index_table->version);
    }
  else
    printf_filtered (" faked for \"readnow\"\n");
  printf_filtered ("\n");
}

static void
dw2_expand_symtabs_for_function (struct objfile *objfile,
				 const char *func_name)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  struct dw2_symtab_iterator iter;
  struct dwarf2_per_cu_data *per_cu;

  dw2_symtab_iter_init (&iter, dwarf2_per_objfile, {}, VAR_DOMAIN, func_name);

  while ((per_cu = dw2_symtab_iter_next (&iter)) != NULL)
    dw2_instantiate_symtab (per_cu, false);

}

static void
dw2_expand_all_symtabs (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);
  int total_units = (dwarf2_per_objfile->all_comp_units.size ()
		     + dwarf2_per_objfile->all_type_units.size ());

  for (int i = 0; i < total_units; ++i)
    {
      dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (i);

      /* We don't want to directly expand a partial CU, because if we
	 read it with the wrong language, then assertion failures can
	 be triggered later on.  See PR symtab/23010.  So, tell
	 dw2_instantiate_symtab to skip partial CUs -- any important
	 partial CU will be read via DW_TAG_imported_unit anyway.  */
      dw2_instantiate_symtab (per_cu, true);
    }
}

static void
dw2_expand_symtabs_with_fullname (struct objfile *objfile,
				  const char *fullname)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* We don't need to consider type units here.
     This is only called for examining code, e.g. expand_line_sal.
     There can be an order of magnitude (or more) more type units
     than comp units, and we avoid them if we can.  */

  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      /* We only need to look at symtabs not already expanded.  */
      if (per_cu->v.quick->compunit_symtab)
	continue;

      quick_file_names *file_data = dw2_get_file_names (per_cu);
      if (file_data == NULL)
	continue;

      for (int j = 0; j < file_data->num_file_names; ++j)
	{
	  const char *this_fullname = file_data->file_names[j];

	  if (filename_cmp (this_fullname, fullname) == 0)
	    {
	      dw2_instantiate_symtab (per_cu, false);
	      break;
	    }
	}
    }
}

static void
dw2_map_matching_symbols
  (struct objfile *objfile,
   const lookup_name_info &name, domain_enum domain,
   int global,
   gdb::function_view<symbol_found_callback_ftype> callback,
   symbol_compare_ftype *ordered_compare)
{
  /* Currently unimplemented; used for Ada.  The function can be called if the
     current language is Ada for a non-Ada objfile using GNU index.  As Ada
     does not look for non-Ada symbols this function should just return.  */
}

/* Starting from a search name, return the string that finds the upper
   bound of all strings that start with SEARCH_NAME in a sorted name
   list.  Returns the empty string to indicate that the upper bound is
   the end of the list.  */

static std::string
make_sort_after_prefix_name (const char *search_name)
{
  /* When looking to complete "func", we find the upper bound of all
     symbols that start with "func" by looking for where we'd insert
     the closest string that would follow "func" in lexicographical
     order.  Usually, that's "func"-with-last-character-incremented,
     i.e. "fund".  Mind non-ASCII characters, though.  Usually those
     will be UTF-8 multi-byte sequences, but we can't be certain.
     Especially mind the 0xff character, which is a valid character in
     non-UTF-8 source character sets (e.g. Latin1 'ÿ'), and we can't
     rule out compilers allowing it in identifiers.  Note that
     conveniently, strcmp/strcasecmp are specified to compare
     characters interpreted as unsigned char.  So what we do is treat
     the whole string as a base 256 number composed of a sequence of
     base 256 "digits" and add 1 to it.  I.e., adding 1 to 0xff wraps
     to 0, and carries 1 to the following more-significant position.
     If the very first character in SEARCH_NAME ends up incremented
     and carries/overflows, then the upper bound is the end of the
     list.  The string after the empty string is also the empty
     string.

     Some examples of this operation:

       SEARCH_NAME  => "+1" RESULT

       "abc"              => "abd"
       "ab\xff"           => "ac"
       "\xff" "a" "\xff"  => "\xff" "b"
       "\xff"             => ""
       "\xff\xff"         => ""
       ""                 => ""

     Then, with these symbols for example:

      func
      func1
      fund

     completing "func" looks for symbols between "func" and
     "func"-with-last-character-incremented, i.e. "fund" (exclusive),
     which finds "func" and "func1", but not "fund".

     And with:

      funcÿ     (Latin1 'ÿ' [0xff])
      funcÿ1
      fund

     completing "funcÿ" looks for symbols between "funcÿ" and "fund"
     (exclusive), which finds "funcÿ" and "funcÿ1", but not "fund".

     And with:

      ÿÿ        (Latin1 'ÿ' [0xff])
      ÿÿ1

     completing "ÿ" or "ÿÿ" looks for symbols between between "ÿÿ" and
     the end of the list.
  */
  std::string after = search_name;
  while (!after.empty () && (unsigned char) after.back () == 0xff)
    after.pop_back ();
  if (!after.empty ())
    after.back () = (unsigned char) after.back () + 1;
  return after;
}

/* See declaration.  */

std::pair<std::vector<name_component>::const_iterator,
	  std::vector<name_component>::const_iterator>
mapped_index_base::find_name_components_bounds
  (const lookup_name_info &lookup_name_without_params, language lang) const
{
  auto *name_cmp
    = this->name_components_casing == case_sensitive_on ? strcmp : strcasecmp;

  const char *lang_name
    = lookup_name_without_params.language_lookup_name (lang).c_str ();

  /* Comparison function object for lower_bound that matches against a
     given symbol name.  */
  auto lookup_compare_lower = [&] (const name_component &elem,
				   const char *name)
    {
      const char *elem_qualified = this->symbol_name_at (elem.idx);
      const char *elem_name = elem_qualified + elem.name_offset;
      return name_cmp (elem_name, name) < 0;
    };

  /* Comparison function object for upper_bound that matches against a
     given symbol name.  */
  auto lookup_compare_upper = [&] (const char *name,
				   const name_component &elem)
    {
      const char *elem_qualified = this->symbol_name_at (elem.idx);
      const char *elem_name = elem_qualified + elem.name_offset;
      return name_cmp (name, elem_name) < 0;
    };

  auto begin = this->name_components.begin ();
  auto end = this->name_components.end ();

  /* Find the lower bound.  */
  auto lower = [&] ()
    {
      if (lookup_name_without_params.completion_mode () && lang_name[0] == '\0')
	return begin;
      else
	return std::lower_bound (begin, end, lang_name, lookup_compare_lower);
    } ();

  /* Find the upper bound.  */
  auto upper = [&] ()
    {
      if (lookup_name_without_params.completion_mode ())
	{
	  /* In completion mode, we want UPPER to point past all
	     symbols names that have the same prefix.  I.e., with
	     these symbols, and completing "func":

	      function        << lower bound
	      function1
	      other_function  << upper bound

	     We find the upper bound by looking for the insertion
	     point of "func"-with-last-character-incremented,
	     i.e. "fund".  */
	  std::string after = make_sort_after_prefix_name (lang_name);
	  if (after.empty ())
	    return end;
	  return std::lower_bound (lower, end, after.c_str (),
				   lookup_compare_lower);
	}
      else
	return std::upper_bound (lower, end, lang_name, lookup_compare_upper);
    } ();

  return {lower, upper};
}

/* See declaration.  */

void
mapped_index_base::build_name_components ()
{
  if (!this->name_components.empty ())
    return;

  this->name_components_casing = case_sensitivity;
  auto *name_cmp
    = this->name_components_casing == case_sensitive_on ? strcmp : strcasecmp;

  /* The code below only knows how to break apart components of C++
     symbol names (and other languages that use '::' as
     namespace/module separator) and Ada symbol names.  */
  auto count = this->symbol_name_count ();
  for (offset_type idx = 0; idx < count; idx++)
    {
      if (this->symbol_name_slot_invalid (idx))
	continue;

      const char *name = this->symbol_name_at (idx);

      /* Add each name component to the name component table.  */
      unsigned int previous_len = 0;

      if (strstr (name, "::") != nullptr)
	{
	  for (unsigned int current_len = cp_find_first_component (name);
	       name[current_len] != '\0';
	       current_len += cp_find_first_component (name + current_len))
	    {
	      gdb_assert (name[current_len] == ':');
	      this->name_components.push_back ({previous_len, idx});
	      /* Skip the '::'.  */
	      current_len += 2;
	      previous_len = current_len;
	    }
	}
      else
	{
	  /* Handle the Ada encoded (aka mangled) form here.  */
	  for (const char *iter = strstr (name, "__");
	       iter != nullptr;
	       iter = strstr (iter, "__"))
	    {
	      this->name_components.push_back ({previous_len, idx});
	      iter += 2;
	      previous_len = iter - name;
	    }
	}

      this->name_components.push_back ({previous_len, idx});
    }

  /* Sort name_components elements by name.  */
  auto name_comp_compare = [&] (const name_component &left,
				const name_component &right)
    {
      const char *left_qualified = this->symbol_name_at (left.idx);
      const char *right_qualified = this->symbol_name_at (right.idx);

      const char *left_name = left_qualified + left.name_offset;
      const char *right_name = right_qualified + right.name_offset;

      return name_cmp (left_name, right_name) < 0;
    };

  std::sort (this->name_components.begin (),
	     this->name_components.end (),
	     name_comp_compare);
}

/* Helper for dw2_expand_symtabs_matching that works with a
   mapped_index_base instead of the containing objfile.  This is split
   to a separate function in order to be able to unit test the
   name_components matching using a mock mapped_index_base.  For each
   symbol name that matches, calls MATCH_CALLBACK, passing it the
   symbol's index in the mapped_index_base symbol table.  */

static void
dw2_expand_symtabs_matching_symbol
  (mapped_index_base &index,
   const lookup_name_info &lookup_name_in,
   gdb::function_view<expand_symtabs_symbol_matcher_ftype> symbol_matcher,
   enum search_domain kind,
   gdb::function_view<bool (offset_type)> match_callback)
{
  lookup_name_info lookup_name_without_params
    = lookup_name_in.make_ignore_params ();

  /* Build the symbol name component sorted vector, if we haven't
     yet.  */
  index.build_name_components ();

  /* The same symbol may appear more than once in the range though.
     E.g., if we're looking for symbols that complete "w", and we have
     a symbol named "w1::w2", we'll find the two name components for
     that same symbol in the range.  To be sure we only call the
     callback once per symbol, we first collect the symbol name
     indexes that matched in a temporary vector and ignore
     duplicates.  */
  std::vector<offset_type> matches;

  struct name_and_matcher
  {
    symbol_name_matcher_ftype *matcher;
    const std::string &name;

    bool operator== (const name_and_matcher &other) const
    {
      return matcher == other.matcher && name == other.name;
    }
  };

  /* A vector holding all the different symbol name matchers, for all
     languages.  */
  std::vector<name_and_matcher> matchers;

  for (int i = 0; i < nr_languages; i++)
    {
      enum language lang_e = (enum language) i;

      const language_defn *lang = language_def (lang_e);
      symbol_name_matcher_ftype *name_matcher
	= get_symbol_name_matcher (lang, lookup_name_without_params);

      name_and_matcher key {
         name_matcher,
	 lookup_name_without_params.language_lookup_name (lang_e)
      };

      /* Don't insert the same comparison routine more than once.
	 Note that we do this linear walk.  This is not a problem in
	 practice because the number of supported languages is
	 low.  */
      if (std::find (matchers.begin (), matchers.end (), key)
	  != matchers.end ())
	continue;
      matchers.push_back (std::move (key));

      auto bounds
	= index.find_name_components_bounds (lookup_name_without_params,
					     lang_e);

      /* Now for each symbol name in range, check to see if we have a name
	 match, and if so, call the MATCH_CALLBACK callback.  */

      for (; bounds.first != bounds.second; ++bounds.first)
	{
	  const char *qualified = index.symbol_name_at (bounds.first->idx);

	  if (!name_matcher (qualified, lookup_name_without_params, NULL)
	      || (symbol_matcher != NULL && !symbol_matcher (qualified)))
	    continue;

	  matches.push_back (bounds.first->idx);
	}
    }

  std::sort (matches.begin (), matches.end ());

  /* Finally call the callback, once per match.  */
  ULONGEST prev = -1;
  for (offset_type idx : matches)
    {
      if (prev != idx)
	{
	  if (!match_callback (idx))
	    break;
	  prev = idx;
	}
    }

  /* Above we use a type wider than idx's for 'prev', since 0 and
     (offset_type)-1 are both possible values.  */
  static_assert (sizeof (prev) > sizeof (offset_type), "");
}

#if GDB_SELF_TEST

namespace selftests { namespace dw2_expand_symtabs_matching {

/* A mock .gdb_index/.debug_names-like name index table, enough to
   exercise dw2_expand_symtabs_matching_symbol, which works with the
   mapped_index_base interface.  Builds an index from the symbol list
   passed as parameter to the constructor.  */
class mock_mapped_index : public mapped_index_base
{
public:
  mock_mapped_index (gdb::array_view<const char *> symbols)
    : m_symbol_table (symbols)
  {}

  DISABLE_COPY_AND_ASSIGN (mock_mapped_index);

  /* Return the number of names in the symbol table.  */
  size_t symbol_name_count () const override
  {
    return m_symbol_table.size ();
  }

  /* Get the name of the symbol at IDX in the symbol table.  */
  const char *symbol_name_at (offset_type idx) const override
  {
    return m_symbol_table[idx];
  }

private:
  gdb::array_view<const char *> m_symbol_table;
};

/* Convenience function that converts a NULL pointer to a "<null>"
   string, to pass to print routines.  */

static const char *
string_or_null (const char *str)
{
  return str != NULL ? str : "<null>";
}

/* Check if a lookup_name_info built from
   NAME/MATCH_TYPE/COMPLETION_MODE matches the symbols in the mock
   index.  EXPECTED_LIST is the list of expected matches, in expected
   matching order.  If no match expected, then an empty list is
   specified.  Returns true on success.  On failure prints a warning
   indicating the file:line that failed, and returns false.  */

static bool
check_match (const char *file, int line,
	     mock_mapped_index &mock_index,
	     const char *name, symbol_name_match_type match_type,
	     bool completion_mode,
	     std::initializer_list<const char *> expected_list)
{
  lookup_name_info lookup_name (name, match_type, completion_mode);

  bool matched = true;

  auto mismatch = [&] (const char *expected_str,
		       const char *got)
  {
    warning (_("%s:%d: match_type=%s, looking-for=\"%s\", "
	       "expected=\"%s\", got=\"%s\"\n"),
	     file, line,
	     (match_type == symbol_name_match_type::FULL
	      ? "FULL" : "WILD"),
	     name, string_or_null (expected_str), string_or_null (got));
    matched = false;
  };

  auto expected_it = expected_list.begin ();
  auto expected_end = expected_list.end ();

  dw2_expand_symtabs_matching_symbol (mock_index, lookup_name,
				      NULL, ALL_DOMAIN,
				      [&] (offset_type idx)
  {
    const char *matched_name = mock_index.symbol_name_at (idx);
    const char *expected_str
      = expected_it == expected_end ? NULL : *expected_it++;

    if (expected_str == NULL || strcmp (expected_str, matched_name) != 0)
      mismatch (expected_str, matched_name);
    return true;
  });

  const char *expected_str
  = expected_it == expected_end ? NULL : *expected_it++;
  if (expected_str != NULL)
    mismatch (expected_str, NULL);

  return matched;
}

/* The symbols added to the mock mapped_index for testing (in
   canonical form).  */
static const char *test_symbols[] = {
  "function",
  "std::bar",
  "std::zfunction",
  "std::zfunction2",
  "w1::w2",
  "ns::foo<char*>",
  "ns::foo<int>",
  "ns::foo<long>",
  "ns2::tmpl<int>::foo2",
  "(anonymous namespace)::A::B::C",

  /* These are used to check that the increment-last-char in the
     matching algorithm for completion doesn't match "t1_fund" when
     completing "t1_func".  */
  "t1_func",
  "t1_func1",
  "t1_fund",
  "t1_fund1",

  /* A UTF-8 name with multi-byte sequences to make sure that
     cp-name-parser understands this as a single identifier ("função"
     is "function" in PT).  */
  u8"u8função",

  /* \377 (0xff) is Latin1 'ÿ'.  */
  "yfunc\377",

  /* \377 (0xff) is Latin1 'ÿ'.  */
  "\377",
  "\377\377123",

  /* A name with all sorts of complications.  Starts with "z" to make
     it easier for the completion tests below.  */
#define Z_SYM_NAME \
  "z::std::tuple<(anonymous namespace)::ui*, std::bar<(anonymous namespace)::ui> >" \
    "::tuple<(anonymous namespace)::ui*, " \
    "std::default_delete<(anonymous namespace)::ui>, void>"

  Z_SYM_NAME
};

/* Returns true if the mapped_index_base::find_name_component_bounds
   method finds EXPECTED_SYMS in INDEX when looking for SEARCH_NAME,
   in completion mode.  */

static bool
check_find_bounds_finds (mapped_index_base &index,
			 const char *search_name,
			 gdb::array_view<const char *> expected_syms)
{
  lookup_name_info lookup_name (search_name,
				symbol_name_match_type::FULL, true);

  auto bounds = index.find_name_components_bounds (lookup_name,
						   language_cplus);

  size_t distance = std::distance (bounds.first, bounds.second);
  if (distance != expected_syms.size ())
    return false;

  for (size_t exp_elem = 0; exp_elem < distance; exp_elem++)
    {
      auto nc_elem = bounds.first + exp_elem;
      const char *qualified = index.symbol_name_at (nc_elem->idx);
      if (strcmp (qualified, expected_syms[exp_elem]) != 0)
	return false;
    }

  return true;
}

/* Test the lower-level mapped_index::find_name_component_bounds
   method.  */

static void
test_mapped_index_find_name_component_bounds ()
{
  mock_mapped_index mock_index (test_symbols);

  mock_index.build_name_components ();

  /* Test the lower-level mapped_index::find_name_component_bounds
     method in completion mode.  */
  {
    static const char *expected_syms[] = {
      "t1_func",
      "t1_func1",
    };

    SELF_CHECK (check_find_bounds_finds (mock_index,
					 "t1_func", expected_syms));
  }

  /* Check that the increment-last-char in the name matching algorithm
     for completion doesn't get confused with Ansi1 'ÿ' / 0xff.  */
  {
    static const char *expected_syms1[] = {
      "\377",
      "\377\377123",
    };
    SELF_CHECK (check_find_bounds_finds (mock_index,
					 "\377", expected_syms1));

    static const char *expected_syms2[] = {
      "\377\377123",
    };
    SELF_CHECK (check_find_bounds_finds (mock_index,
					 "\377\377", expected_syms2));
  }
}

/* Test dw2_expand_symtabs_matching_symbol.  */

static void
test_dw2_expand_symtabs_matching_symbol ()
{
  mock_mapped_index mock_index (test_symbols);

  /* We let all tests run until the end even if some fails, for debug
     convenience.  */
  bool any_mismatch = false;

  /* Create the expected symbols list (an initializer_list).  Needed
     because lists have commas, and we need to pass them to CHECK,
     which is a macro.  */
#define EXPECT(...) { __VA_ARGS__ }

  /* Wrapper for check_match that passes down the current
     __FILE__/__LINE__.  */
#define CHECK_MATCH(NAME, MATCH_TYPE, COMPLETION_MODE, EXPECTED_LIST)	\
  any_mismatch |= !check_match (__FILE__, __LINE__,			\
				mock_index,				\
				NAME, MATCH_TYPE, COMPLETION_MODE,	\
				EXPECTED_LIST)

  /* Identity checks.  */
  for (const char *sym : test_symbols)
    {
      /* Should be able to match all existing symbols.  */
      CHECK_MATCH (sym, symbol_name_match_type::FULL, false,
		   EXPECT (sym));

      /* Should be able to match all existing symbols with
	 parameters.  */
      std::string with_params = std::string (sym) + "(int)";
      CHECK_MATCH (with_params.c_str (), symbol_name_match_type::FULL, false,
		   EXPECT (sym));

      /* Should be able to match all existing symbols with
	 parameters and qualifiers.  */
      with_params = std::string (sym) + " ( int ) const";
      CHECK_MATCH (with_params.c_str (), symbol_name_match_type::FULL, false,
		   EXPECT (sym));

      /* This should really find sym, but cp-name-parser.y doesn't
	 know about lvalue/rvalue qualifiers yet.  */
      with_params = std::string (sym) + " ( int ) &&";
      CHECK_MATCH (with_params.c_str (), symbol_name_match_type::FULL, false,
		   {});
    }

  /* Check that the name matching algorithm for completion doesn't get
     confused with Latin1 'ÿ' / 0xff.  */
  {
    static const char str[] = "\377";
    CHECK_MATCH (str, symbol_name_match_type::FULL, true,
		 EXPECT ("\377", "\377\377123"));
  }

  /* Check that the increment-last-char in the matching algorithm for
     completion doesn't match "t1_fund" when completing "t1_func".  */
  {
    static const char str[] = "t1_func";
    CHECK_MATCH (str, symbol_name_match_type::FULL, true,
		 EXPECT ("t1_func", "t1_func1"));
  }

  /* Check that completion mode works at each prefix of the expected
     symbol name.  */
  {
    static const char str[] = "function(int)";
    size_t len = strlen (str);
    std::string lookup;

    for (size_t i = 1; i < len; i++)
      {
	lookup.assign (str, i);
	CHECK_MATCH (lookup.c_str (), symbol_name_match_type::FULL, true,
		     EXPECT ("function"));
      }
  }

  /* While "w" is a prefix of both components, the match function
     should still only be called once.  */
  {
    CHECK_MATCH ("w", symbol_name_match_type::FULL, true,
		 EXPECT ("w1::w2"));
    CHECK_MATCH ("w", symbol_name_match_type::WILD, true,
		 EXPECT ("w1::w2"));
  }

  /* Same, with a "complicated" symbol.  */
  {
    static const char str[] = Z_SYM_NAME;
    size_t len = strlen (str);
    std::string lookup;

    for (size_t i = 1; i < len; i++)
      {
	lookup.assign (str, i);
	CHECK_MATCH (lookup.c_str (), symbol_name_match_type::FULL, true,
		     EXPECT (Z_SYM_NAME));
      }
  }

  /* In FULL mode, an incomplete symbol doesn't match.  */
  {
    CHECK_MATCH ("std::zfunction(int", symbol_name_match_type::FULL, false,
		 {});
  }

  /* A complete symbol with parameters matches any overload, since the
     index has no overload info.  */
  {
    CHECK_MATCH ("std::zfunction(int)", symbol_name_match_type::FULL, true,
		 EXPECT ("std::zfunction", "std::zfunction2"));
    CHECK_MATCH ("zfunction(int)", symbol_name_match_type::WILD, true,
		 EXPECT ("std::zfunction", "std::zfunction2"));
    CHECK_MATCH ("zfunc", symbol_name_match_type::WILD, true,
		 EXPECT ("std::zfunction", "std::zfunction2"));
  }

  /* Check that whitespace is ignored appropriately.  A symbol with a
     template argument list. */
  {
    static const char expected[] = "ns::foo<int>";
    CHECK_MATCH ("ns :: foo < int > ", symbol_name_match_type::FULL, false,
		 EXPECT (expected));
    CHECK_MATCH ("foo < int > ", symbol_name_match_type::WILD, false,
		 EXPECT (expected));
  }

  /* Check that whitespace is ignored appropriately.  A symbol with a
     template argument list that includes a pointer.  */
  {
    static const char expected[] = "ns::foo<char*>";
    /* Try both completion and non-completion modes.  */
    static const bool completion_mode[2] = {false, true};
    for (size_t i = 0; i < 2; i++)
      {
	CHECK_MATCH ("ns :: foo < char * >", symbol_name_match_type::FULL,
		     completion_mode[i], EXPECT (expected));
	CHECK_MATCH ("foo < char * >", symbol_name_match_type::WILD,
		     completion_mode[i], EXPECT (expected));

	CHECK_MATCH ("ns :: foo < char * > (int)", symbol_name_match_type::FULL,
		     completion_mode[i], EXPECT (expected));
	CHECK_MATCH ("foo < char * > (int)", symbol_name_match_type::WILD,
		     completion_mode[i], EXPECT (expected));
      }
  }

  {
    /* Check method qualifiers are ignored.  */
    static const char expected[] = "ns::foo<char*>";
    CHECK_MATCH ("ns :: foo < char * >  ( int ) const",
		 symbol_name_match_type::FULL, true, EXPECT (expected));
    CHECK_MATCH ("ns :: foo < char * >  ( int ) &&",
		 symbol_name_match_type::FULL, true, EXPECT (expected));
    CHECK_MATCH ("foo < char * >  ( int ) const",
		 symbol_name_match_type::WILD, true, EXPECT (expected));
    CHECK_MATCH ("foo < char * >  ( int ) &&",
		 symbol_name_match_type::WILD, true, EXPECT (expected));
  }

  /* Test lookup names that don't match anything.  */
  {
    CHECK_MATCH ("bar2", symbol_name_match_type::WILD, false,
		 {});

    CHECK_MATCH ("doesntexist", symbol_name_match_type::FULL, false,
		 {});
  }

  /* Some wild matching tests, exercising "(anonymous namespace)",
     which should not be confused with a parameter list.  */
  {
    static const char *syms[] = {
      "A::B::C",
      "B::C",
      "C",
      "A :: B :: C ( int )",
      "B :: C ( int )",
      "C ( int )",
    };

    for (const char *s : syms)
      {
	CHECK_MATCH (s, symbol_name_match_type::WILD, false,
		     EXPECT ("(anonymous namespace)::A::B::C"));
      }
  }

  {
    static const char expected[] = "ns2::tmpl<int>::foo2";
    CHECK_MATCH ("tmp", symbol_name_match_type::WILD, true,
		 EXPECT (expected));
    CHECK_MATCH ("tmpl<", symbol_name_match_type::WILD, true,
		 EXPECT (expected));
  }

  SELF_CHECK (!any_mismatch);

#undef EXPECT
#undef CHECK_MATCH
}

static void
run_test ()
{
  test_mapped_index_find_name_component_bounds ();
  test_dw2_expand_symtabs_matching_symbol ();
}

}} // namespace selftests::dw2_expand_symtabs_matching

#endif /* GDB_SELF_TEST */

/* If FILE_MATCHER is NULL or if PER_CU has
   dwarf2_per_cu_quick_data::MARK set (see
   dw_expand_symtabs_matching_file_matcher), expand the CU and call
   EXPANSION_NOTIFY on it.  */

static void
dw2_expand_symtabs_matching_one
  (struct dwarf2_per_cu_data *per_cu,
   gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher,
   gdb::function_view<expand_symtabs_exp_notify_ftype> expansion_notify)
{
  if (file_matcher == NULL || per_cu->v.quick->mark)
    {
      bool symtab_was_null
	= (per_cu->v.quick->compunit_symtab == NULL);

      dw2_instantiate_symtab (per_cu, false);

      if (expansion_notify != NULL
	  && symtab_was_null
	  && per_cu->v.quick->compunit_symtab != NULL)
	expansion_notify (per_cu->v.quick->compunit_symtab);
    }
}

/* Helper for dw2_expand_matching symtabs.  Called on each symbol
   matched, to expand corresponding CUs that were marked.  IDX is the
   index of the symbol name that matched.  */

static void
dw2_expand_marked_cus
  (struct dwarf2_per_objfile *dwarf2_per_objfile, offset_type idx,
   gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher,
   gdb::function_view<expand_symtabs_exp_notify_ftype> expansion_notify,
   search_domain kind)
{
  offset_type *vec, vec_len, vec_idx;
  bool global_seen = false;
  mapped_index &index = *dwarf2_per_objfile->index_table;

  vec = (offset_type *) (index.constant_pool
			 + MAYBE_SWAP (index.symbol_table[idx].vec));
  vec_len = MAYBE_SWAP (vec[0]);
  for (vec_idx = 0; vec_idx < vec_len; ++vec_idx)
    {
      offset_type cu_index_and_attrs = MAYBE_SWAP (vec[vec_idx + 1]);
      /* This value is only valid for index versions >= 7.  */
      int is_static = GDB_INDEX_SYMBOL_STATIC_VALUE (cu_index_and_attrs);
      gdb_index_symbol_kind symbol_kind =
	GDB_INDEX_SYMBOL_KIND_VALUE (cu_index_and_attrs);
      int cu_index = GDB_INDEX_CU_VALUE (cu_index_and_attrs);
      /* Only check the symbol attributes if they're present.
	 Indices prior to version 7 don't record them,
	 and indices >= 7 may elide them for certain symbols
	 (gold does this).  */
      int attrs_valid =
	(index.version >= 7
	 && symbol_kind != GDB_INDEX_SYMBOL_KIND_NONE);

      /* Work around gold/15646.  */
      if (attrs_valid)
	{
	  if (!is_static && global_seen)
	    continue;
	  if (!is_static)
	    global_seen = true;
	}

      /* Only check the symbol's kind if it has one.  */
      if (attrs_valid)
	{
	  switch (kind)
	    {
	    case VARIABLES_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_VARIABLE)
		continue;
	      break;
	    case FUNCTIONS_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_FUNCTION)
		continue;
	      break;
	    case TYPES_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_TYPE)
		continue;
	      break;
	    case MODULES_DOMAIN:
	      if (symbol_kind != GDB_INDEX_SYMBOL_KIND_OTHER)
		continue;
	      break;
	    default:
	      break;
	    }
	}

      /* Don't crash on bad data.  */
      if (cu_index >= (dwarf2_per_objfile->all_comp_units.size ()
		       + dwarf2_per_objfile->all_type_units.size ()))
	{
	  complaint (_(".gdb_index entry has bad CU index"
		       " [in module %s]"),
		       objfile_name (dwarf2_per_objfile->objfile));
	  continue;
	}

      dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (cu_index);
      dw2_expand_symtabs_matching_one (per_cu, file_matcher,
				       expansion_notify);
    }
}

/* If FILE_MATCHER is non-NULL, set all the
   dwarf2_per_cu_quick_data::MARK of the current DWARF2_PER_OBJFILE
   that match FILE_MATCHER.  */

static void
dw_expand_symtabs_matching_file_matcher
  (struct dwarf2_per_objfile *dwarf2_per_objfile,
   gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher)
{
  if (file_matcher == NULL)
    return;

  objfile *const objfile = dwarf2_per_objfile->objfile;

  htab_up visited_found (htab_create_alloc (10, htab_hash_pointer,
					    htab_eq_pointer,
					    NULL, xcalloc, xfree));
  htab_up visited_not_found (htab_create_alloc (10, htab_hash_pointer,
						htab_eq_pointer,
						NULL, xcalloc, xfree));

  /* The rule is CUs specify all the files, including those used by
     any TU, so there's no need to scan TUs here.  */

  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      QUIT;

      per_cu->v.quick->mark = 0;

      /* We only need to look at symtabs not already expanded.  */
      if (per_cu->v.quick->compunit_symtab)
	continue;

      quick_file_names *file_data = dw2_get_file_names (per_cu);
      if (file_data == NULL)
	continue;

      if (htab_find (visited_not_found.get (), file_data) != NULL)
	continue;
      else if (htab_find (visited_found.get (), file_data) != NULL)
	{
	  per_cu->v.quick->mark = 1;
	  continue;
	}

      for (int j = 0; j < file_data->num_file_names; ++j)
	{
	  const char *this_real_name;

	  if (file_matcher (file_data->file_names[j], false))
	    {
	      per_cu->v.quick->mark = 1;
	      break;
	    }

	  /* Before we invoke realpath, which can get expensive when many
	     files are involved, do a quick comparison of the basenames.  */
	  if (!basenames_may_differ
	      && !file_matcher (lbasename (file_data->file_names[j]),
				true))
	    continue;

	  this_real_name = dw2_get_real_path (objfile, file_data, j);
	  if (file_matcher (this_real_name, false))
	    {
	      per_cu->v.quick->mark = 1;
	      break;
	    }
	}

      void **slot = htab_find_slot (per_cu->v.quick->mark
				    ? visited_found.get ()
				    : visited_not_found.get (),
				    file_data, INSERT);
      *slot = file_data;
    }
}

static void
dw2_expand_symtabs_matching
  (struct objfile *objfile,
   gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher,
   const lookup_name_info &lookup_name,
   gdb::function_view<expand_symtabs_symbol_matcher_ftype> symbol_matcher,
   gdb::function_view<expand_symtabs_exp_notify_ftype> expansion_notify,
   enum search_domain kind)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* index_table is NULL if OBJF_READNOW.  */
  if (!dwarf2_per_objfile->index_table)
    return;

  dw_expand_symtabs_matching_file_matcher (dwarf2_per_objfile, file_matcher);

  mapped_index &index = *dwarf2_per_objfile->index_table;

  dw2_expand_symtabs_matching_symbol (index, lookup_name,
				      symbol_matcher,
				      kind, [&] (offset_type idx)
    {
      dw2_expand_marked_cus (dwarf2_per_objfile, idx, file_matcher,
			     expansion_notify, kind);
      return true;
    });
}

/* A helper for dw2_find_pc_sect_compunit_symtab which finds the most specific
   symtab.  */

static struct compunit_symtab *
recursively_find_pc_sect_compunit_symtab (struct compunit_symtab *cust,
					  CORE_ADDR pc)
{
  int i;

  if (COMPUNIT_BLOCKVECTOR (cust) != NULL
      && blockvector_contains_pc (COMPUNIT_BLOCKVECTOR (cust), pc))
    return cust;

  if (cust->includes == NULL)
    return NULL;

  for (i = 0; cust->includes[i]; ++i)
    {
      struct compunit_symtab *s = cust->includes[i];

      s = recursively_find_pc_sect_compunit_symtab (s, pc);
      if (s != NULL)
	return s;
    }

  return NULL;
}

static struct compunit_symtab *
dw2_find_pc_sect_compunit_symtab (struct objfile *objfile,
				  struct bound_minimal_symbol msymbol,
				  CORE_ADDR pc,
				  struct obj_section *section,
				  int warn_if_readin)
{
  struct dwarf2_per_cu_data *data;
  struct compunit_symtab *result;

  if (!objfile->partial_symtabs->psymtabs_addrmap)
    return NULL;

  CORE_ADDR baseaddr = ANOFFSET (objfile->section_offsets,
				 SECT_OFF_TEXT (objfile));
  data = (struct dwarf2_per_cu_data *) addrmap_find
    (objfile->partial_symtabs->psymtabs_addrmap, pc - baseaddr);
  if (!data)
    return NULL;

  if (warn_if_readin && data->v.quick->compunit_symtab)
    warning (_("(Internal error: pc %s in read in CU, but not in symtab.)"),
	     paddress (get_objfile_arch (objfile), pc));

  result
    = recursively_find_pc_sect_compunit_symtab (dw2_instantiate_symtab (data,
									false),
						pc);
  gdb_assert (result != NULL);
  return result;
}

static void
dw2_map_symbol_filenames (struct objfile *objfile, symbol_filename_ftype *fun,
			  void *data, int need_fullname)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  if (!dwarf2_per_objfile->filenames_cache)
    {
      dwarf2_per_objfile->filenames_cache.emplace ();

      htab_up visited (htab_create_alloc (10,
					  htab_hash_pointer, htab_eq_pointer,
					  NULL, xcalloc, xfree));

      /* The rule is CUs specify all the files, including those used
	 by any TU, so there's no need to scan TUs here.  We can
	 ignore file names coming from already-expanded CUs.  */

      for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
	{
	  if (per_cu->v.quick->compunit_symtab)
	    {
	      void **slot = htab_find_slot (visited.get (),
					    per_cu->v.quick->file_names,
					    INSERT);

	      *slot = per_cu->v.quick->file_names;
	    }
	}

      for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
	{
	  /* We only need to look at symtabs not already expanded.  */
	  if (per_cu->v.quick->compunit_symtab)
	    continue;

	  quick_file_names *file_data = dw2_get_file_names (per_cu);
	  if (file_data == NULL)
	    continue;

	  void **slot = htab_find_slot (visited.get (), file_data, INSERT);
	  if (*slot)
	    {
	      /* Already visited.  */
	      continue;
	    }
	  *slot = file_data;

	  for (int j = 0; j < file_data->num_file_names; ++j)
	    {
	      const char *filename = file_data->file_names[j];
	      dwarf2_per_objfile->filenames_cache->seen (filename);
	    }
	}
    }

  dwarf2_per_objfile->filenames_cache->traverse ([&] (const char *filename)
    {
      gdb::unique_xmalloc_ptr<char> this_real_name;

      if (need_fullname)
	this_real_name = gdb_realpath (filename);
      (*fun) (filename, this_real_name.get (), data);
    });
}

static int
dw2_has_symbols (struct objfile *objfile)
{
  return 1;
}

const struct quick_symbol_functions dwarf2_gdb_index_functions =
{
  dw2_has_symbols,
  dw2_find_last_source_symtab,
  dw2_forget_cached_source_info,
  dw2_map_symtabs_matching_filename,
  dw2_lookup_symbol,
  dw2_print_stats,
  dw2_dump,
  dw2_expand_symtabs_for_function,
  dw2_expand_all_symtabs,
  dw2_expand_symtabs_with_fullname,
  dw2_map_matching_symbols,
  dw2_expand_symtabs_matching,
  dw2_find_pc_sect_compunit_symtab,
  NULL,
  dw2_map_symbol_filenames
};

/* DWARF-5 debug_names reader.  */

/* DWARF-5 augmentation string for GDB's DW_IDX_GNU_* extension.  */
static const gdb_byte dwarf5_augmentation[] = { 'G', 'D', 'B', 0 };

/* A helper function that reads the .debug_names section in SECTION
   and fills in MAP.  FILENAME is the name of the file containing the
   section; it is used for error reporting.

   Returns true if all went well, false otherwise.  */

static bool
read_debug_names_from_section (struct objfile *objfile,
			       const char *filename,
			       struct dwarf2_section_info *section,
			       mapped_debug_names &map)
{
  if (dwarf2_section_empty_p (section))
    return false;

  /* Older elfutils strip versions could keep the section in the main
     executable while splitting it for the separate debug info file.  */
  if ((get_section_flags (section) & SEC_HAS_CONTENTS) == 0)
    return false;

  dwarf2_read_section (objfile, section);

  map.dwarf5_byte_order = gdbarch_byte_order (get_objfile_arch (objfile));

  const gdb_byte *addr = section->buffer;

  bfd *const abfd = get_section_bfd_owner (section);

  unsigned int bytes_read;
  LONGEST length = read_initial_length (abfd, addr, &bytes_read);
  addr += bytes_read;

  map.dwarf5_is_dwarf64 = bytes_read != 4;
  map.offset_size = map.dwarf5_is_dwarf64 ? 8 : 4;
  if (bytes_read + length != section->size)
    {
      /* There may be multiple per-CU indices.  */
      warning (_("Section .debug_names in %s length %s does not match "
		 "section length %s, ignoring .debug_names."),
	       filename, plongest (bytes_read + length),
	       pulongest (section->size));
      return false;
    }

  /* The version number.  */
  uint16_t version = read_2_bytes (abfd, addr);
  addr += 2;
  if (version != 5)
    {
      warning (_("Section .debug_names in %s has unsupported version %d, "
		 "ignoring .debug_names."),
	       filename, version);
      return false;
    }

  /* Padding.  */
  uint16_t padding = read_2_bytes (abfd, addr);
  addr += 2;
  if (padding != 0)
    {
      warning (_("Section .debug_names in %s has unsupported padding %d, "
		 "ignoring .debug_names."),
	       filename, padding);
      return false;
    }

  /* comp_unit_count - The number of CUs in the CU list.  */
  map.cu_count = read_4_bytes (abfd, addr);
  addr += 4;

  /* local_type_unit_count - The number of TUs in the local TU
     list.  */
  map.tu_count = read_4_bytes (abfd, addr);
  addr += 4;

  /* foreign_type_unit_count - The number of TUs in the foreign TU
     list.  */
  uint32_t foreign_tu_count = read_4_bytes (abfd, addr);
  addr += 4;
  if (foreign_tu_count != 0)
    {
      warning (_("Section .debug_names in %s has unsupported %lu foreign TUs, "
		 "ignoring .debug_names."),
	       filename, static_cast<unsigned long> (foreign_tu_count));
      return false;
    }

  /* bucket_count - The number of hash buckets in the hash lookup
     table.  */
  map.bucket_count = read_4_bytes (abfd, addr);
  addr += 4;

  /* name_count - The number of unique names in the index.  */
  map.name_count = read_4_bytes (abfd, addr);
  addr += 4;

  /* abbrev_table_size - The size in bytes of the abbreviations
     table.  */
  uint32_t abbrev_table_size = read_4_bytes (abfd, addr);
  addr += 4;

  /* augmentation_string_size - The size in bytes of the augmentation
     string.  This value is rounded up to a multiple of 4.  */
  uint32_t augmentation_string_size = read_4_bytes (abfd, addr);
  addr += 4;
  map.augmentation_is_gdb = ((augmentation_string_size
			      == sizeof (dwarf5_augmentation))
			     && memcmp (addr, dwarf5_augmentation,
					sizeof (dwarf5_augmentation)) == 0);
  augmentation_string_size += (-augmentation_string_size) & 3;
  addr += augmentation_string_size;

  /* List of CUs */
  map.cu_table_reordered = addr;
  addr += map.cu_count * map.offset_size;

  /* List of Local TUs */
  map.tu_table_reordered = addr;
  addr += map.tu_count * map.offset_size;

  /* Hash Lookup Table */
  map.bucket_table_reordered = reinterpret_cast<const uint32_t *> (addr);
  addr += map.bucket_count * 4;
  map.hash_table_reordered = reinterpret_cast<const uint32_t *> (addr);
  addr += map.name_count * 4;

  /* Name Table */
  map.name_table_string_offs_reordered = addr;
  addr += map.name_count * map.offset_size;
  map.name_table_entry_offs_reordered = addr;
  addr += map.name_count * map.offset_size;

  const gdb_byte *abbrev_table_start = addr;
  for (;;)
    {
      const ULONGEST index_num = read_unsigned_leb128 (abfd, addr, &bytes_read);
      addr += bytes_read;
      if (index_num == 0)
	break;

      const auto insertpair
	= map.abbrev_map.emplace (index_num, mapped_debug_names::index_val ());
      if (!insertpair.second)
	{
	  warning (_("Section .debug_names in %s has duplicate index %s, "
		     "ignoring .debug_names."),
		   filename, pulongest (index_num));
	  return false;
	}
      mapped_debug_names::index_val &indexval = insertpair.first->second;
      indexval.dwarf_tag = read_unsigned_leb128 (abfd, addr, &bytes_read);
      addr += bytes_read;

      for (;;)
	{
	  mapped_debug_names::index_val::attr attr;
	  attr.dw_idx = read_unsigned_leb128 (abfd, addr, &bytes_read);
	  addr += bytes_read;
	  attr.form = read_unsigned_leb128 (abfd, addr, &bytes_read);
	  addr += bytes_read;
	  if (attr.form == DW_FORM_implicit_const)
	    {
	      attr.implicit_const = read_signed_leb128 (abfd, addr,
							&bytes_read);
	      addr += bytes_read;
	    }
	  if (attr.dw_idx == 0 && attr.form == 0)
	    break;
	  indexval.attr_vec.push_back (std::move (attr));
	}
    }
  if (addr != abbrev_table_start + abbrev_table_size)
    {
      warning (_("Section .debug_names in %s has abbreviation_table "
		 "of size %s vs. written as %u, ignoring .debug_names."),
	       filename, plongest (addr - abbrev_table_start),
	       abbrev_table_size);
      return false;
    }
  map.entry_pool = addr;

  return true;
}

/* A helper for create_cus_from_debug_names that handles the MAP's CU
   list.  */

static void
create_cus_from_debug_names_list (struct dwarf2_per_objfile *dwarf2_per_objfile,
				  const mapped_debug_names &map,
				  dwarf2_section_info &section,
				  bool is_dwz)
{
  sect_offset sect_off_prev;
  for (uint32_t i = 0; i <= map.cu_count; ++i)
    {
      sect_offset sect_off_next;
      if (i < map.cu_count)
	{
	  sect_off_next
	    = (sect_offset) (extract_unsigned_integer
			     (map.cu_table_reordered + i * map.offset_size,
			      map.offset_size,
			      map.dwarf5_byte_order));
	}
      else
	sect_off_next = (sect_offset) section.size;
      if (i >= 1)
	{
	  const ULONGEST length = sect_off_next - sect_off_prev;
	  dwarf2_per_cu_data *per_cu
	    = create_cu_from_index_list (dwarf2_per_objfile, &section, is_dwz,
					 sect_off_prev, length);
	  dwarf2_per_objfile->all_comp_units.push_back (per_cu);
	}
      sect_off_prev = sect_off_next;
    }
}

/* Read the CU list from the mapped index, and use it to create all
   the CU objects for this dwarf2_per_objfile.  */

static void
create_cus_from_debug_names (struct dwarf2_per_objfile *dwarf2_per_objfile,
			     const mapped_debug_names &map,
			     const mapped_debug_names &dwz_map)
{
  gdb_assert (dwarf2_per_objfile->all_comp_units.empty ());
  dwarf2_per_objfile->all_comp_units.reserve (map.cu_count + dwz_map.cu_count);

  create_cus_from_debug_names_list (dwarf2_per_objfile, map,
				    dwarf2_per_objfile->info,
				    false /* is_dwz */);

  if (dwz_map.cu_count == 0)
    return;

  dwz_file *dwz = dwarf2_get_dwz_file (dwarf2_per_objfile);
  create_cus_from_debug_names_list (dwarf2_per_objfile, dwz_map, dwz->info,
				    true /* is_dwz */);
}

/* Read .debug_names.  If everything went ok, initialize the "quick"
   elements of all the CUs and return true.  Otherwise, return false.  */

static bool
dwarf2_read_debug_names (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  std::unique_ptr<mapped_debug_names> map
    (new mapped_debug_names (dwarf2_per_objfile));
  mapped_debug_names dwz_map (dwarf2_per_objfile);
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  if (!read_debug_names_from_section (objfile, objfile_name (objfile),
				      &dwarf2_per_objfile->debug_names,
				      *map))
    return false;

  /* Don't use the index if it's empty.  */
  if (map->name_count == 0)
    return false;

  /* If there is a .dwz file, read it so we can get its CU list as
     well.  */
  dwz_file *dwz = dwarf2_get_dwz_file (dwarf2_per_objfile);
  if (dwz != NULL)
    {
      if (!read_debug_names_from_section (objfile,
					  bfd_get_filename (dwz->dwz_bfd.get ()),
					  &dwz->debug_names, dwz_map))
	{
	  warning (_("could not read '.debug_names' section from %s; skipping"),
		   bfd_get_filename (dwz->dwz_bfd.get ()));
	  return false;
	}
    }

  create_cus_from_debug_names (dwarf2_per_objfile, *map, dwz_map);

  if (map->tu_count != 0)
    {
      /* We can only handle a single .debug_types when we have an
	 index.  */
      if (dwarf2_per_objfile->types.size () != 1)
	return false;

      dwarf2_section_info *section = &dwarf2_per_objfile->types[0];

      create_signatured_type_table_from_debug_names
	(dwarf2_per_objfile, *map, section, &dwarf2_per_objfile->abbrev);
    }

  create_addrmap_from_aranges (dwarf2_per_objfile,
			       &dwarf2_per_objfile->debug_aranges);

  dwarf2_per_objfile->debug_names_table = std::move (map);
  dwarf2_per_objfile->using_index = 1;
  dwarf2_per_objfile->quick_file_names_table =
    create_quick_file_names_table (dwarf2_per_objfile->all_comp_units.size ());

  return true;
}

/* Type used to manage iterating over all CUs looking for a symbol for
   .debug_names.  */

class dw2_debug_names_iterator
{
public:
  dw2_debug_names_iterator (const mapped_debug_names &map,
			    gdb::optional<block_enum> block_index,
			    domain_enum domain,
			    const char *name)
    : m_map (map), m_block_index (block_index), m_domain (domain),
      m_addr (find_vec_in_debug_names (map, name))
  {}

  dw2_debug_names_iterator (const mapped_debug_names &map,
			    search_domain search, uint32_t namei)
    : m_map (map),
      m_search (search),
      m_addr (find_vec_in_debug_names (map, namei))
  {}

  dw2_debug_names_iterator (const mapped_debug_names &map,
			    block_enum block_index, domain_enum domain,
			    uint32_t namei)
    : m_map (map), m_block_index (block_index), m_domain (domain),
      m_addr (find_vec_in_debug_names (map, namei))
  {}

  /* Return the next matching CU or NULL if there are no more.  */
  dwarf2_per_cu_data *next ();

private:
  static const gdb_byte *find_vec_in_debug_names (const mapped_debug_names &map,
						  const char *name);
  static const gdb_byte *find_vec_in_debug_names (const mapped_debug_names &map,
						  uint32_t namei);

  /* The internalized form of .debug_names.  */
  const mapped_debug_names &m_map;

  /* If set, only look for symbols that match that block.  Valid values are
     GLOBAL_BLOCK and STATIC_BLOCK.  */
  const gdb::optional<block_enum> m_block_index;

  /* The kind of symbol we're looking for.  */
  const domain_enum m_domain = UNDEF_DOMAIN;
  const search_domain m_search = ALL_DOMAIN;

  /* The list of CUs from the index entry of the symbol, or NULL if
     not found.  */
  const gdb_byte *m_addr;
};

const char *
mapped_debug_names::namei_to_name (uint32_t namei) const
{
  const ULONGEST namei_string_offs
    = extract_unsigned_integer ((name_table_string_offs_reordered
				 + namei * offset_size),
				offset_size,
				dwarf5_byte_order);
  return read_indirect_string_at_offset
    (dwarf2_per_objfile, dwarf2_per_objfile->objfile->obfd, namei_string_offs);
}

/* Find a slot in .debug_names for the object named NAME.  If NAME is
   found, return pointer to its pool data.  If NAME cannot be found,
   return NULL.  */

const gdb_byte *
dw2_debug_names_iterator::find_vec_in_debug_names
  (const mapped_debug_names &map, const char *name)
{
  int (*cmp) (const char *, const char *);

  gdb::unique_xmalloc_ptr<char> without_params;
  if (current_language->la_language == language_cplus
      || current_language->la_language == language_fortran
      || current_language->la_language == language_d)
    {
      /* NAME is already canonical.  Drop any qualifiers as
	 .debug_names does not contain any.  */

      if (strchr (name, '(') != NULL)
	{
	  without_params = cp_remove_params (name);
	  if (without_params != NULL)
	    name = without_params.get ();
	}
    }

  cmp = (case_sensitivity == case_sensitive_on ? strcmp : strcasecmp);

  const uint32_t full_hash = dwarf5_djb_hash (name);
  uint32_t namei
    = extract_unsigned_integer (reinterpret_cast<const gdb_byte *>
				(map.bucket_table_reordered
				 + (full_hash % map.bucket_count)), 4,
				map.dwarf5_byte_order);
  if (namei == 0)
    return NULL;
  --namei;
  if (namei >= map.name_count)
    {
      complaint (_("Wrong .debug_names with name index %u but name_count=%u "
		   "[in module %s]"),
		 namei, map.name_count,
		 objfile_name (map.dwarf2_per_objfile->objfile));
      return NULL;
    }

  for (;;)
    {
      const uint32_t namei_full_hash
	= extract_unsigned_integer (reinterpret_cast<const gdb_byte *>
				    (map.hash_table_reordered + namei), 4,
				    map.dwarf5_byte_order);
      if (full_hash % map.bucket_count != namei_full_hash % map.bucket_count)
	return NULL;

      if (full_hash == namei_full_hash)
	{
	  const char *const namei_string = map.namei_to_name (namei);

#if 0 /* An expensive sanity check.  */
	  if (namei_full_hash != dwarf5_djb_hash (namei_string))
	    {
	      complaint (_("Wrong .debug_names hash for string at index %u "
			   "[in module %s]"),
			 namei, objfile_name (dwarf2_per_objfile->objfile));
	      return NULL;
	    }
#endif

	  if (cmp (namei_string, name) == 0)
	    {
	      const ULONGEST namei_entry_offs
		= extract_unsigned_integer ((map.name_table_entry_offs_reordered
					     + namei * map.offset_size),
					    map.offset_size, map.dwarf5_byte_order);
	      return map.entry_pool + namei_entry_offs;
	    }
	}

      ++namei;
      if (namei >= map.name_count)
	return NULL;
    }
}

const gdb_byte *
dw2_debug_names_iterator::find_vec_in_debug_names
  (const mapped_debug_names &map, uint32_t namei)
{
  if (namei >= map.name_count)
    {
      complaint (_("Wrong .debug_names with name index %u but name_count=%u "
		   "[in module %s]"),
		 namei, map.name_count,
		 objfile_name (map.dwarf2_per_objfile->objfile));
      return NULL;
    }

  const ULONGEST namei_entry_offs
    = extract_unsigned_integer ((map.name_table_entry_offs_reordered
				 + namei * map.offset_size),
				map.offset_size, map.dwarf5_byte_order);
  return map.entry_pool + namei_entry_offs;
}

/* See dw2_debug_names_iterator.  */

dwarf2_per_cu_data *
dw2_debug_names_iterator::next ()
{
  if (m_addr == NULL)
    return NULL;

  struct dwarf2_per_objfile *dwarf2_per_objfile = m_map.dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  bfd *const abfd = objfile->obfd;

 again:

  unsigned int bytes_read;
  const ULONGEST abbrev = read_unsigned_leb128 (abfd, m_addr, &bytes_read);
  m_addr += bytes_read;
  if (abbrev == 0)
    return NULL;

  const auto indexval_it = m_map.abbrev_map.find (abbrev);
  if (indexval_it == m_map.abbrev_map.cend ())
    {
      complaint (_("Wrong .debug_names undefined abbrev code %s "
		   "[in module %s]"),
		 pulongest (abbrev), objfile_name (objfile));
      return NULL;
    }
  const mapped_debug_names::index_val &indexval = indexval_it->second;
  enum class symbol_linkage {
    unknown,
    static_,
    extern_,
  } symbol_linkage_ = symbol_linkage::unknown;
  dwarf2_per_cu_data *per_cu = NULL;
  for (const mapped_debug_names::index_val::attr &attr : indexval.attr_vec)
    {
      ULONGEST ull;
      switch (attr.form)
	{
	case DW_FORM_implicit_const:
	  ull = attr.implicit_const;
	  break;
	case DW_FORM_flag_present:
	  ull = 1;
	  break;
	case DW_FORM_udata:
	  ull = read_unsigned_leb128 (abfd, m_addr, &bytes_read);
	  m_addr += bytes_read;
	  break;
	default:
	  complaint (_("Unsupported .debug_names form %s [in module %s]"),
		     dwarf_form_name (attr.form),
		     objfile_name (objfile));
	  return NULL;
	}
      switch (attr.dw_idx)
	{
	case DW_IDX_compile_unit:
	  /* Don't crash on bad data.  */
	  if (ull >= dwarf2_per_objfile->all_comp_units.size ())
	    {
	      complaint (_(".debug_names entry has bad CU index %s"
			   " [in module %s]"),
			 pulongest (ull),
			 objfile_name (dwarf2_per_objfile->objfile));
	      continue;
	    }
	  per_cu = dwarf2_per_objfile->get_cutu (ull);
	  break;
	case DW_IDX_type_unit:
	  /* Don't crash on bad data.  */
	  if (ull >= dwarf2_per_objfile->all_type_units.size ())
	    {
	      complaint (_(".debug_names entry has bad TU index %s"
			   " [in module %s]"),
			 pulongest (ull),
			 objfile_name (dwarf2_per_objfile->objfile));
	      continue;
	    }
	  per_cu = &dwarf2_per_objfile->get_tu (ull)->per_cu;
	  break;
	case DW_IDX_GNU_internal:
	  if (!m_map.augmentation_is_gdb)
	    break;
	  symbol_linkage_ = symbol_linkage::static_;
	  break;
	case DW_IDX_GNU_external:
	  if (!m_map.augmentation_is_gdb)
	    break;
	  symbol_linkage_ = symbol_linkage::extern_;
	  break;
	}
    }

  /* Skip if already read in.  */
  if (per_cu->v.quick->compunit_symtab)
    goto again;

  /* Check static vs global.  */
  if (symbol_linkage_ != symbol_linkage::unknown && m_block_index.has_value ())
    {
	const bool want_static = *m_block_index == STATIC_BLOCK;
	const bool symbol_is_static =
	  symbol_linkage_ == symbol_linkage::static_;
	if (want_static != symbol_is_static)
	  goto again;
    }

  /* Match dw2_symtab_iter_next, symbol_kind
     and debug_names::psymbol_tag.  */
  switch (m_domain)
    {
    case VAR_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_variable:
	case DW_TAG_subprogram:
	/* Some types are also in VAR_DOMAIN.  */
	case DW_TAG_typedef:
	case DW_TAG_structure_type:
	  break;
	default:
	  goto again;
	}
      break;
    case STRUCT_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_typedef:
	case DW_TAG_structure_type:
	  break;
	default:
	  goto again;
	}
      break;
    case LABEL_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case 0:
	case DW_TAG_variable:
	  break;
	default:
	  goto again;
	}
      break;
    case MODULE_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_module:
	  break;
	default:
	  goto again;
	}
      break;
    default:
      break;
    }

  /* Match dw2_expand_symtabs_matching, symbol_kind and
     debug_names::psymbol_tag.  */
  switch (m_search)
    {
    case VARIABLES_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_variable:
	  break;
	default:
	  goto again;
	}
      break;
    case FUNCTIONS_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_subprogram:
	  break;
	default:
	  goto again;
	}
      break;
    case TYPES_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_typedef:
	case DW_TAG_structure_type:
	  break;
	default:
	  goto again;
	}
      break;
    case MODULES_DOMAIN:
      switch (indexval.dwarf_tag)
	{
	case DW_TAG_module:
	  break;
	default:
	  goto again;
	}
    default:
      break;
    }

  return per_cu;
}

static struct compunit_symtab *
dw2_debug_names_lookup_symbol (struct objfile *objfile, block_enum block_index,
			       const char *name, domain_enum domain)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  const auto &mapp = dwarf2_per_objfile->debug_names_table;
  if (!mapp)
    {
      /* index is NULL if OBJF_READNOW.  */
      return NULL;
    }
  const auto &map = *mapp;

  dw2_debug_names_iterator iter (map, block_index, domain, name);

  struct compunit_symtab *stab_best = NULL;
  struct dwarf2_per_cu_data *per_cu;
  while ((per_cu = iter.next ()) != NULL)
    {
      struct symbol *sym, *with_opaque = NULL;
      struct compunit_symtab *stab = dw2_instantiate_symtab (per_cu, false);
      const struct blockvector *bv = COMPUNIT_BLOCKVECTOR (stab);
      const struct block *block = BLOCKVECTOR_BLOCK (bv, block_index);

      sym = block_find_symbol (block, name, domain,
			       block_find_non_opaque_type_preferred,
			       &with_opaque);

      /* Some caution must be observed with overloaded functions and
	 methods, since the index will not contain any overload
	 information (but NAME might contain it).  */

      if (sym != NULL
	  && strcmp_iw (sym->search_name (), name) == 0)
	return stab;
      if (with_opaque != NULL
	  && strcmp_iw (with_opaque->search_name (), name) == 0)
	stab_best = stab;

      /* Keep looking through other CUs.  */
    }

  return stab_best;
}

/* This dumps minimal information about .debug_names.  It is called
   via "mt print objfiles".  The gdb.dwarf2/gdb-index.exp testcase
   uses this to verify that .debug_names has been loaded.  */

static void
dw2_debug_names_dump (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  gdb_assert (dwarf2_per_objfile->using_index);
  printf_filtered (".debug_names:");
  if (dwarf2_per_objfile->debug_names_table)
    printf_filtered (" exists\n");
  else
    printf_filtered (" faked for \"readnow\"\n");
  printf_filtered ("\n");
}

static void
dw2_debug_names_expand_symtabs_for_function (struct objfile *objfile,
					     const char *func_name)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* dwarf2_per_objfile->debug_names_table is NULL if OBJF_READNOW.  */
  if (dwarf2_per_objfile->debug_names_table)
    {
      const mapped_debug_names &map = *dwarf2_per_objfile->debug_names_table;

      dw2_debug_names_iterator iter (map, {}, VAR_DOMAIN, func_name);

      struct dwarf2_per_cu_data *per_cu;
      while ((per_cu = iter.next ()) != NULL)
	dw2_instantiate_symtab (per_cu, false);
    }
}

static void
dw2_debug_names_map_matching_symbols
  (struct objfile *objfile,
   const lookup_name_info &name, domain_enum domain,
   int global,
   gdb::function_view<symbol_found_callback_ftype> callback,
   symbol_compare_ftype *ordered_compare)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* debug_names_table is NULL if OBJF_READNOW.  */
  if (!dwarf2_per_objfile->debug_names_table)
    return;

  mapped_debug_names &map = *dwarf2_per_objfile->debug_names_table;
  const block_enum block_kind = global ? GLOBAL_BLOCK : STATIC_BLOCK;

  const char *match_name = name.ada ().lookup_name ().c_str ();
  auto matcher = [&] (const char *symname)
    {
      if (ordered_compare == nullptr)
	return true;
      return ordered_compare (symname, match_name) == 0;
    };

  dw2_expand_symtabs_matching_symbol (map, name, matcher, ALL_DOMAIN,
				      [&] (offset_type namei)
    {
      /* The name was matched, now expand corresponding CUs that were
	 marked.  */
      dw2_debug_names_iterator iter (map, block_kind, domain, namei);

      struct dwarf2_per_cu_data *per_cu;
      while ((per_cu = iter.next ()) != NULL)
	dw2_expand_symtabs_matching_one (per_cu, nullptr, nullptr);
      return true;
    });

  /* It's a shame we couldn't do this inside the
     dw2_expand_symtabs_matching_symbol callback, but that skips CUs
     that have already been expanded.  Instead, this loop matches what
     the psymtab code does.  */
  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      struct compunit_symtab *cust = per_cu->v.quick->compunit_symtab;
      if (cust != nullptr)
	{
	  const struct block *block
	    = BLOCKVECTOR_BLOCK (COMPUNIT_BLOCKVECTOR (cust), block_kind);
	  if (!iterate_over_symbols_terminated (block, name,
						domain, callback))
	    break;
	}
    }
}

static void
dw2_debug_names_expand_symtabs_matching
  (struct objfile *objfile,
   gdb::function_view<expand_symtabs_file_matcher_ftype> file_matcher,
   const lookup_name_info &lookup_name,
   gdb::function_view<expand_symtabs_symbol_matcher_ftype> symbol_matcher,
   gdb::function_view<expand_symtabs_exp_notify_ftype> expansion_notify,
   enum search_domain kind)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* debug_names_table is NULL if OBJF_READNOW.  */
  if (!dwarf2_per_objfile->debug_names_table)
    return;

  dw_expand_symtabs_matching_file_matcher (dwarf2_per_objfile, file_matcher);

  mapped_debug_names &map = *dwarf2_per_objfile->debug_names_table;

  dw2_expand_symtabs_matching_symbol (map, lookup_name,
				      symbol_matcher,
				      kind, [&] (offset_type namei)
    {
      /* The name was matched, now expand corresponding CUs that were
	 marked.  */
      dw2_debug_names_iterator iter (map, kind, namei);

      struct dwarf2_per_cu_data *per_cu;
      while ((per_cu = iter.next ()) != NULL)
	dw2_expand_symtabs_matching_one (per_cu, file_matcher,
					 expansion_notify);
      return true;
    });
}

const struct quick_symbol_functions dwarf2_debug_names_functions =
{
  dw2_has_symbols,
  dw2_find_last_source_symtab,
  dw2_forget_cached_source_info,
  dw2_map_symtabs_matching_filename,
  dw2_debug_names_lookup_symbol,
  dw2_print_stats,
  dw2_debug_names_dump,
  dw2_debug_names_expand_symtabs_for_function,
  dw2_expand_all_symtabs,
  dw2_expand_symtabs_with_fullname,
  dw2_debug_names_map_matching_symbols,
  dw2_debug_names_expand_symtabs_matching,
  dw2_find_pc_sect_compunit_symtab,
  NULL,
  dw2_map_symbol_filenames
};

/* Get the content of the .gdb_index section of OBJ.  SECTION_OWNER should point
   to either a dwarf2_per_objfile or dwz_file object.  */

template <typename T>
static gdb::array_view<const gdb_byte>
get_gdb_index_contents_from_section (objfile *obj, T *section_owner)
{
  dwarf2_section_info *section = &section_owner->gdb_index;

  if (dwarf2_section_empty_p (section))
    return {};

  /* Older elfutils strip versions could keep the section in the main
     executable while splitting it for the separate debug info file.  */
  if ((get_section_flags (section) & SEC_HAS_CONTENTS) == 0)
    return {};

  dwarf2_read_section (obj, section);

  /* dwarf2_section_info::size is a bfd_size_type, while
     gdb::array_view works with size_t.  On 32-bit hosts, with
     --enable-64-bit-bfd, bfd_size_type is a 64-bit type, while size_t
     is 32-bit.  So we need an explicit narrowing conversion here.
     This is fine, because it's impossible to allocate or mmap an
     array/buffer larger than what size_t can represent.  */
  return gdb::make_array_view (section->buffer, section->size);
}

/* Lookup the index cache for the contents of the index associated to
   DWARF2_OBJ.  */

static gdb::array_view<const gdb_byte>
get_gdb_index_contents_from_cache (objfile *obj, dwarf2_per_objfile *dwarf2_obj)
{
  const bfd_build_id *build_id = build_id_bfd_get (obj->obfd);
  if (build_id == nullptr)
    return {};

  return global_index_cache.lookup_gdb_index (build_id,
					      &dwarf2_obj->index_cache_res);
}

/* Same as the above, but for DWZ.  */

static gdb::array_view<const gdb_byte>
get_gdb_index_contents_from_cache_dwz (objfile *obj, dwz_file *dwz)
{
  const bfd_build_id *build_id = build_id_bfd_get (dwz->dwz_bfd.get ());
  if (build_id == nullptr)
    return {};

  return global_index_cache.lookup_gdb_index (build_id, &dwz->index_cache_res);
}

/* See symfile.h.  */

bool
dwarf2_initialize_objfile (struct objfile *objfile, dw_index_kind *index_kind)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  /* If we're about to read full symbols, don't bother with the
     indices.  In this case we also don't care if some other debug
     format is making psymtabs, because they are all about to be
     expanded anyway.  */
  if ((objfile->flags & OBJF_READNOW))
    {
      dwarf2_per_objfile->using_index = 1;
      create_all_comp_units (dwarf2_per_objfile);
      create_all_type_units (dwarf2_per_objfile);
      dwarf2_per_objfile->quick_file_names_table
	= create_quick_file_names_table
	    (dwarf2_per_objfile->all_comp_units.size ());

      for (int i = 0; i < (dwarf2_per_objfile->all_comp_units.size ()
			   + dwarf2_per_objfile->all_type_units.size ()); ++i)
	{
	  dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (i);

	  per_cu->v.quick = OBSTACK_ZALLOC (&objfile->objfile_obstack,
					    struct dwarf2_per_cu_quick_data);
	}

      /* Return 1 so that gdb sees the "quick" functions.  However,
	 these functions will be no-ops because we will have expanded
	 all symtabs.  */
      *index_kind = dw_index_kind::GDB_INDEX;
      return true;
    }

  if (dwarf2_read_debug_names (dwarf2_per_objfile))
    {
      *index_kind = dw_index_kind::DEBUG_NAMES;
      return true;
    }

  if (dwarf2_read_gdb_index (dwarf2_per_objfile,
			     get_gdb_index_contents_from_section<struct dwarf2_per_objfile>,
			     get_gdb_index_contents_from_section<dwz_file>))
    {
      *index_kind = dw_index_kind::GDB_INDEX;
      return true;
    }

  /* ... otherwise, try to find the index in the index cache.  */
  if (dwarf2_read_gdb_index (dwarf2_per_objfile,
			     get_gdb_index_contents_from_cache,
			     get_gdb_index_contents_from_cache_dwz))
    {
      global_index_cache.hit ();
      *index_kind = dw_index_kind::GDB_INDEX;
      return true;
    }

  global_index_cache.miss ();
  return false;
}



/* Build a partial symbol table.  */

void
dwarf2_build_psymtabs (struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  init_psymbol_list (objfile, 1024);

  try
    {
      /* This isn't really ideal: all the data we allocate on the
	 objfile's obstack is still uselessly kept around.  However,
	 freeing it seems unsafe.  */
      psymtab_discarder psymtabs (objfile);
      dwarf2_build_psymtabs_hard (dwarf2_per_objfile);
      psymtabs.keep ();

      /* (maybe) store an index in the cache.  */
      global_index_cache.store (dwarf2_per_objfile);
    }
  catch (const gdb_exception_error &except)
    {
      exception_print (gdb_stderr, except);
    }
}

/* Return the total length of the CU described by HEADER.  */

static unsigned int
get_cu_length (const struct comp_unit_head *header)
{
  return header->initial_length_size + header->length;
}

/* Return TRUE if SECT_OFF is within CU_HEADER.  */

static inline bool
offset_in_cu_p (const comp_unit_head *cu_header, sect_offset sect_off)
{
  sect_offset bottom = cu_header->sect_off;
  sect_offset top = cu_header->sect_off + get_cu_length (cu_header);

  return sect_off >= bottom && sect_off < top;
}

/* Find the base address of the compilation unit for range lists and
   location lists.  It will normally be specified by DW_AT_low_pc.
   In DWARF-3 draft 4, the base address could be overridden by
   DW_AT_entry_pc.  It's been removed, but GCC still uses this for
   compilation units with discontinuous ranges.  */

static void
dwarf2_find_base_address (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr;

  cu->base_known = 0;
  cu->base_address = 0;

  attr = dwarf2_attr (die, DW_AT_entry_pc, cu);
  if (attr != nullptr)
    {
      cu->base_address = attr_value_as_address (attr);
      cu->base_known = 1;
    }
  else
    {
      attr = dwarf2_attr (die, DW_AT_low_pc, cu);
      if (attr != nullptr)
	{
	  cu->base_address = attr_value_as_address (attr);
	  cu->base_known = 1;
	}
    }
}

/* Read in the comp unit header information from the debug_info at info_ptr.
   Use rcuh_kind::COMPILE as the default type if not known by the caller.
   NOTE: This leaves members offset, first_die_offset to be filled in
   by the caller.  */

static const gdb_byte *
read_comp_unit_head (struct comp_unit_head *cu_header,
		     const gdb_byte *info_ptr,
		     struct dwarf2_section_info *section,
		     rcuh_kind section_kind)
{
  int signed_addr;
  unsigned int bytes_read;
  const char *filename = get_section_file_name (section);
  bfd *abfd = get_section_bfd_owner (section);

  cu_header->length = read_initial_length (abfd, info_ptr, &bytes_read);
  cu_header->initial_length_size = bytes_read;
  cu_header->offset_size = (bytes_read == 4) ? 4 : 8;
  info_ptr += bytes_read;
  cu_header->version = read_2_bytes (abfd, info_ptr);
  if (cu_header->version < 2 || cu_header->version > 5)
    error (_("Dwarf Error: wrong version in compilation unit header "
	   "(is %d, should be 2, 3, 4 or 5) [in module %s]"),
	   cu_header->version, filename);
  info_ptr += 2;
  if (cu_header->version < 5)
    switch (section_kind)
      {
      case rcuh_kind::COMPILE:
	cu_header->unit_type = DW_UT_compile;
	break;
      case rcuh_kind::TYPE:
	cu_header->unit_type = DW_UT_type;
	break;
      default:
	internal_error (__FILE__, __LINE__,
			_("read_comp_unit_head: invalid section_kind"));
      }
  else
    {
      cu_header->unit_type = static_cast<enum dwarf_unit_type>
						 (read_1_byte (abfd, info_ptr));
      info_ptr += 1;
      switch (cu_header->unit_type)
	{
	case DW_UT_compile:
	case DW_UT_partial:
	case DW_UT_skeleton:
	case DW_UT_split_compile:
	  break;
	case DW_UT_type:
	case DW_UT_split_type:
	  section_kind = rcuh_kind::TYPE;
	  break;
	default:
	  error (_("Dwarf Error: wrong unit_type in compilation unit header "
		 "(is %#04x, should be one of: %s, %s, %s, %s or %s) "
		 "[in module %s]"), cu_header->unit_type,
		 dwarf_unit_type_name (DW_UT_compile),
		 dwarf_unit_type_name (DW_UT_skeleton),
		 dwarf_unit_type_name (DW_UT_split_compile),
		 dwarf_unit_type_name (DW_UT_type),
		 dwarf_unit_type_name (DW_UT_split_type), filename);
	}

      cu_header->addr_size = read_1_byte (abfd, info_ptr);
      info_ptr += 1;
    }
  cu_header->abbrev_sect_off = (sect_offset) read_offset (abfd, info_ptr,
							  cu_header,
							  &bytes_read);
  info_ptr += bytes_read;
  if (cu_header->version < 5)
    {
      cu_header->addr_size = read_1_byte (abfd, info_ptr);
      info_ptr += 1;
    }
  signed_addr = bfd_get_sign_extend_vma (abfd);
  if (signed_addr < 0)
    internal_error (__FILE__, __LINE__,
		    _("read_comp_unit_head: dwarf from non elf file"));
  cu_header->signed_addr_p = signed_addr;

  bool header_has_signature = section_kind == rcuh_kind::TYPE
    || cu_header->unit_type == DW_UT_skeleton
    || cu_header->unit_type == DW_UT_split_compile;

  if (header_has_signature)
    {
      cu_header->signature = read_8_bytes (abfd, info_ptr);
      info_ptr += 8;
    }

  if (section_kind == rcuh_kind::TYPE)
    {
      LONGEST type_offset;
      type_offset = read_offset (abfd, info_ptr, cu_header, &bytes_read);
      info_ptr += bytes_read;
      cu_header->type_cu_offset_in_tu = (cu_offset) type_offset;
      if (to_underlying (cu_header->type_cu_offset_in_tu) != type_offset)
	error (_("Dwarf Error: Too big type_offset in compilation unit "
	       "header (is %s) [in module %s]"), plongest (type_offset),
	       filename);
    }

  return info_ptr;
}

/* Helper function that returns the proper abbrev section for
   THIS_CU.  */

static struct dwarf2_section_info *
get_abbrev_section_for_cu (struct dwarf2_per_cu_data *this_cu)
{
  struct dwarf2_section_info *abbrev;
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_cu->dwarf2_per_objfile;

  if (this_cu->is_dwz)
    abbrev = &dwarf2_get_dwz_file (dwarf2_per_objfile)->abbrev;
  else
    abbrev = &dwarf2_per_objfile->abbrev;

  return abbrev;
}

/* Subroutine of read_and_check_comp_unit_head and
   read_and_check_type_unit_head to simplify them.
   Perform various error checking on the header.  */

static void
error_check_comp_unit_head (struct dwarf2_per_objfile *dwarf2_per_objfile,
			    struct comp_unit_head *header,
			    struct dwarf2_section_info *section,
			    struct dwarf2_section_info *abbrev_section)
{
  const char *filename = get_section_file_name (section);

  if (to_underlying (header->abbrev_sect_off)
      >= dwarf2_section_size (dwarf2_per_objfile->objfile, abbrev_section))
    error (_("Dwarf Error: bad offset (%s) in compilation unit header "
	   "(offset %s + 6) [in module %s]"),
	   sect_offset_str (header->abbrev_sect_off),
	   sect_offset_str (header->sect_off),
	   filename);

  /* Cast to ULONGEST to use 64-bit arithmetic when possible to
     avoid potential 32-bit overflow.  */
  if (((ULONGEST) header->sect_off + get_cu_length (header))
      > section->size)
    error (_("Dwarf Error: bad length (0x%x) in compilation unit header "
	   "(offset %s + 0) [in module %s]"),
	   header->length, sect_offset_str (header->sect_off),
	   filename);
}

/* Read in a CU/TU header and perform some basic error checking.
   The contents of the header are stored in HEADER.
   The result is a pointer to the start of the first DIE.  */

static const gdb_byte *
read_and_check_comp_unit_head (struct dwarf2_per_objfile *dwarf2_per_objfile,
			       struct comp_unit_head *header,
			       struct dwarf2_section_info *section,
			       struct dwarf2_section_info *abbrev_section,
			       const gdb_byte *info_ptr,
			       rcuh_kind section_kind)
{
  const gdb_byte *beg_of_comp_unit = info_ptr;

  header->sect_off = (sect_offset) (beg_of_comp_unit - section->buffer);

  info_ptr = read_comp_unit_head (header, info_ptr, section, section_kind);

  header->first_die_cu_offset = (cu_offset) (info_ptr - beg_of_comp_unit);

  error_check_comp_unit_head (dwarf2_per_objfile, header, section,
			      abbrev_section);

  return info_ptr;
}

/* Fetch the abbreviation table offset from a comp or type unit header.  */

static sect_offset
read_abbrev_offset (struct dwarf2_per_objfile *dwarf2_per_objfile,
		    struct dwarf2_section_info *section,
		    sect_offset sect_off)
{
  bfd *abfd = get_section_bfd_owner (section);
  const gdb_byte *info_ptr;
  unsigned int initial_length_size, offset_size;
  uint16_t version;

  dwarf2_read_section (dwarf2_per_objfile->objfile, section);
  info_ptr = section->buffer + to_underlying (sect_off);
  read_initial_length (abfd, info_ptr, &initial_length_size);
  offset_size = initial_length_size == 4 ? 4 : 8;
  info_ptr += initial_length_size;

  version = read_2_bytes (abfd, info_ptr);
  info_ptr += 2;
  if (version >= 5)
    {
      /* Skip unit type and address size.  */
      info_ptr += 2;
    }

  return (sect_offset) read_offset_1 (abfd, info_ptr, offset_size);
}

/* Allocate a new partial symtab for file named NAME and mark this new
   partial symtab as being an include of PST.  */

static void
dwarf2_create_include_psymtab (const char *name, struct partial_symtab *pst,
                               struct objfile *objfile)
{
  struct partial_symtab *subpst = allocate_psymtab (name, objfile);

  if (!IS_ABSOLUTE_PATH (subpst->filename))
    {
      /* It shares objfile->objfile_obstack.  */
      subpst->dirname = pst->dirname;
    }

  subpst->dependencies = objfile->partial_symtabs->allocate_dependencies (1);
  subpst->dependencies[0] = pst;
  subpst->number_of_dependencies = 1;

  subpst->read_symtab = pst->read_symtab;

  /* No private part is necessary for include psymtabs.  This property
     can be used to differentiate between such include psymtabs and
     the regular ones.  */
  subpst->read_symtab_private = NULL;
}

/* Read the Line Number Program data and extract the list of files
   included by the source file represented by PST.  Build an include
   partial symtab for each of these included files.  */

static void
dwarf2_build_include_psymtabs (struct dwarf2_cu *cu,
			       struct die_info *die,
			       struct partial_symtab *pst)
{
  line_header_up lh;
  struct attribute *attr;

  attr = dwarf2_attr (die, DW_AT_stmt_list, cu);
  if (attr != nullptr)
    lh = dwarf_decode_line_header ((sect_offset) DW_UNSND (attr), cu);
  if (lh == NULL)
    return;  /* No linetable, so no includes.  */

  /* NOTE: pst->dirname is DW_AT_comp_dir (if present).  Also note
     that we pass in the raw text_low here; that is ok because we're
     only decoding the line table to make include partial symtabs, and
     so the addresses aren't really used.  */
  dwarf_decode_lines (lh.get (), pst->dirname, cu, pst,
		      pst->raw_text_low (), 1);
}

static hashval_t
hash_signatured_type (const void *item)
{
  const struct signatured_type *sig_type
    = (const struct signatured_type *) item;

  /* This drops the top 32 bits of the signature, but is ok for a hash.  */
  return sig_type->signature;
}

static int
eq_signatured_type (const void *item_lhs, const void *item_rhs)
{
  const struct signatured_type *lhs = (const struct signatured_type *) item_lhs;
  const struct signatured_type *rhs = (const struct signatured_type *) item_rhs;

  return lhs->signature == rhs->signature;
}

/* Allocate a hash table for signatured types.  */

static htab_t
allocate_signatured_type_table (struct objfile *objfile)
{
  return htab_create_alloc_ex (41,
			       hash_signatured_type,
			       eq_signatured_type,
			       NULL,
			       &objfile->objfile_obstack,
			       hashtab_obstack_allocate,
			       dummy_obstack_deallocate);
}

/* A helper function to add a signatured type CU to a table.  */

static int
add_signatured_type_cu_to_table (void **slot, void *datum)
{
  struct signatured_type *sigt = (struct signatured_type *) *slot;
  std::vector<signatured_type *> *all_type_units
    = (std::vector<signatured_type *> *) datum;

  all_type_units->push_back (sigt);

  return 1;
}

/* A helper for create_debug_types_hash_table.  Read types from SECTION
   and fill them into TYPES_HTAB.  It will process only type units,
   therefore DW_UT_type.  */

static void
create_debug_type_hash_table (struct dwarf2_per_objfile *dwarf2_per_objfile,
			      struct dwo_file *dwo_file,
			      dwarf2_section_info *section, htab_t &types_htab,
			      rcuh_kind section_kind)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_section_info *abbrev_section;
  bfd *abfd;
  const gdb_byte *info_ptr, *end_ptr;

  abbrev_section = (dwo_file != NULL
		    ? &dwo_file->sections.abbrev
		    : &dwarf2_per_objfile->abbrev);

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "Reading %s for %s:\n",
			get_section_name (section),
			get_section_file_name (abbrev_section));

  dwarf2_read_section (objfile, section);
  info_ptr = section->buffer;

  if (info_ptr == NULL)
    return;

  /* We can't set abfd until now because the section may be empty or
     not present, in which case the bfd is unknown.  */
  abfd = get_section_bfd_owner (section);

  /* We don't use init_cutu_and_read_dies_simple, or some such, here
     because we don't need to read any dies: the signature is in the
     header.  */

  end_ptr = info_ptr + section->size;
  while (info_ptr < end_ptr)
    {
      struct signatured_type *sig_type;
      struct dwo_unit *dwo_tu;
      void **slot;
      const gdb_byte *ptr = info_ptr;
      struct comp_unit_head header;
      unsigned int length;

      sect_offset sect_off = (sect_offset) (ptr - section->buffer);

      /* Initialize it due to a false compiler warning.  */
      header.signature = -1;
      header.type_cu_offset_in_tu = (cu_offset) -1;

      /* We need to read the type's signature in order to build the hash
	 table, but we don't need anything else just yet.  */

      ptr = read_and_check_comp_unit_head (dwarf2_per_objfile, &header, section,
					   abbrev_section, ptr, section_kind);

      length = get_cu_length (&header);

      /* Skip dummy type units.  */
      if (ptr >= info_ptr + length
	  || peek_abbrev_code (abfd, ptr) == 0
	  || (header.unit_type != DW_UT_type
              && header.unit_type != DW_UT_split_type))
	{
	  info_ptr += length;
	  continue;
	}

      if (types_htab == NULL)
	{
	  if (dwo_file)
	    types_htab = allocate_dwo_unit_table (objfile);
	  else
	    types_htab = allocate_signatured_type_table (objfile);
	}

      if (dwo_file)
	{
	  sig_type = NULL;
	  dwo_tu = OBSTACK_ZALLOC (&objfile->objfile_obstack,
				   struct dwo_unit);
	  dwo_tu->dwo_file = dwo_file;
	  dwo_tu->signature = header.signature;
	  dwo_tu->type_offset_in_tu = header.type_cu_offset_in_tu;
	  dwo_tu->section = section;
	  dwo_tu->sect_off = sect_off;
	  dwo_tu->length = length;
	}
      else
	{
	  /* N.B.: type_offset is not usable if this type uses a DWO file.
	     The real type_offset is in the DWO file.  */
	  dwo_tu = NULL;
	  sig_type = OBSTACK_ZALLOC (&objfile->objfile_obstack,
				     struct signatured_type);
	  sig_type->signature = header.signature;
	  sig_type->type_offset_in_tu = header.type_cu_offset_in_tu;
	  sig_type->per_cu.dwarf2_per_objfile = dwarf2_per_objfile;
	  sig_type->per_cu.is_debug_types = 1;
	  sig_type->per_cu.section = section;
	  sig_type->per_cu.sect_off = sect_off;
	  sig_type->per_cu.length = length;
	}

      slot = htab_find_slot (types_htab,
			     dwo_file ? (void*) dwo_tu : (void *) sig_type,
			     INSERT);
      gdb_assert (slot != NULL);
      if (*slot != NULL)
	{
	  sect_offset dup_sect_off;

	  if (dwo_file)
	    {
	      const struct dwo_unit *dup_tu
		= (const struct dwo_unit *) *slot;

	      dup_sect_off = dup_tu->sect_off;
	    }
	  else
	    {
	      const struct signatured_type *dup_tu
		= (const struct signatured_type *) *slot;

	      dup_sect_off = dup_tu->per_cu.sect_off;
	    }

	  complaint (_("debug type entry at offset %s is duplicate to"
		       " the entry at offset %s, signature %s"),
		     sect_offset_str (sect_off), sect_offset_str (dup_sect_off),
		     hex_string (header.signature));
	}
      *slot = dwo_file ? (void *) dwo_tu : (void *) sig_type;

      if (dwarf_read_debug > 1)
	fprintf_unfiltered (gdb_stdlog, "  offset %s, signature %s\n",
			    sect_offset_str (sect_off),
			    hex_string (header.signature));

      info_ptr += length;
    }
}

/* Create the hash table of all entries in the .debug_types
   (or .debug_types.dwo) section(s).
   If reading a DWO file, then DWO_FILE is a pointer to the DWO file object,
   otherwise it is NULL.

   The result is a pointer to the hash table or NULL if there are no types.

   Note: This function processes DWO files only, not DWP files.  */

static void
create_debug_types_hash_table (struct dwarf2_per_objfile *dwarf2_per_objfile,
			       struct dwo_file *dwo_file,
			       gdb::array_view<dwarf2_section_info> type_sections,
			       htab_t &types_htab)
{
  for (dwarf2_section_info &section : type_sections)
    create_debug_type_hash_table (dwarf2_per_objfile, dwo_file, &section,
				  types_htab, rcuh_kind::TYPE);
}

/* Create the hash table of all entries in the .debug_types section,
   and initialize all_type_units.
   The result is zero if there is an error (e.g. missing .debug_types section),
   otherwise non-zero.	*/

static int
create_all_type_units (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  htab_t types_htab = NULL;

  create_debug_type_hash_table (dwarf2_per_objfile, NULL,
				&dwarf2_per_objfile->info, types_htab,
				rcuh_kind::COMPILE);
  create_debug_types_hash_table (dwarf2_per_objfile, NULL,
				 dwarf2_per_objfile->types, types_htab);
  if (types_htab == NULL)
    {
      dwarf2_per_objfile->signatured_types = NULL;
      return 0;
    }

  dwarf2_per_objfile->signatured_types = types_htab;

  gdb_assert (dwarf2_per_objfile->all_type_units.empty ());
  dwarf2_per_objfile->all_type_units.reserve (htab_elements (types_htab));

  htab_traverse_noresize (types_htab, add_signatured_type_cu_to_table,
			  &dwarf2_per_objfile->all_type_units);

  return 1;
}

/* Add an entry for signature SIG to dwarf2_per_objfile->signatured_types.
   If SLOT is non-NULL, it is the entry to use in the hash table.
   Otherwise we find one.  */

static struct signatured_type *
add_type_unit (struct dwarf2_per_objfile *dwarf2_per_objfile, ULONGEST sig,
	       void **slot)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  if (dwarf2_per_objfile->all_type_units.size ()
      == dwarf2_per_objfile->all_type_units.capacity ())
    ++dwarf2_per_objfile->tu_stats.nr_all_type_units_reallocs;

  signatured_type *sig_type = OBSTACK_ZALLOC (&objfile->objfile_obstack,
					      struct signatured_type);

  dwarf2_per_objfile->all_type_units.push_back (sig_type);
  sig_type->signature = sig;
  sig_type->per_cu.is_debug_types = 1;
  if (dwarf2_per_objfile->using_index)
    {
      sig_type->per_cu.v.quick =
	OBSTACK_ZALLOC (&objfile->objfile_obstack,
			struct dwarf2_per_cu_quick_data);
    }

  if (slot == NULL)
    {
      slot = htab_find_slot (dwarf2_per_objfile->signatured_types,
			     sig_type, INSERT);
    }
  gdb_assert (*slot == NULL);
  *slot = sig_type;
  /* The rest of sig_type must be filled in by the caller.  */
  return sig_type;
}

/* Subroutine of lookup_dwo_signatured_type and lookup_dwp_signatured_type.
   Fill in SIG_ENTRY with DWO_ENTRY.  */

static void
fill_in_sig_entry_from_dwo_entry (struct dwarf2_per_objfile *dwarf2_per_objfile,
				  struct signatured_type *sig_entry,
				  struct dwo_unit *dwo_entry)
{
  /* Make sure we're not clobbering something we don't expect to.  */
  gdb_assert (! sig_entry->per_cu.queued);
  gdb_assert (sig_entry->per_cu.cu == NULL);
  if (dwarf2_per_objfile->using_index)
    {
      gdb_assert (sig_entry->per_cu.v.quick != NULL);
      gdb_assert (sig_entry->per_cu.v.quick->compunit_symtab == NULL);
    }
  else
      gdb_assert (sig_entry->per_cu.v.psymtab == NULL);
  gdb_assert (sig_entry->signature == dwo_entry->signature);
  gdb_assert (to_underlying (sig_entry->type_offset_in_section) == 0);
  gdb_assert (sig_entry->type_unit_group == NULL);
  gdb_assert (sig_entry->dwo_unit == NULL);

  sig_entry->per_cu.section = dwo_entry->section;
  sig_entry->per_cu.sect_off = dwo_entry->sect_off;
  sig_entry->per_cu.length = dwo_entry->length;
  sig_entry->per_cu.reading_dwo_directly = 1;
  sig_entry->per_cu.dwarf2_per_objfile = dwarf2_per_objfile;
  sig_entry->type_offset_in_tu = dwo_entry->type_offset_in_tu;
  sig_entry->dwo_unit = dwo_entry;
}

/* Subroutine of lookup_signatured_type.
   If we haven't read the TU yet, create the signatured_type data structure
   for a TU to be read in directly from a DWO file, bypassing the stub.
   This is the "Stay in DWO Optimization": When there is no DWP file and we're
   using .gdb_index, then when reading a CU we want to stay in the DWO file
   containing that CU.  Otherwise we could end up reading several other DWO
   files (due to comdat folding) to process the transitive closure of all the
   mentioned TUs, and that can be slow.  The current DWO file will have every
   type signature that it needs.
   We only do this for .gdb_index because in the psymtab case we already have
   to read all the DWOs to build the type unit groups.  */

static struct signatured_type *
lookup_dwo_signatured_type (struct dwarf2_cu *cu, ULONGEST sig)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwo_file *dwo_file;
  struct dwo_unit find_dwo_entry, *dwo_entry;
  struct signatured_type find_sig_entry, *sig_entry;
  void **slot;

  gdb_assert (cu->dwo_unit && dwarf2_per_objfile->using_index);

  /* If TU skeletons have been removed then we may not have read in any
     TUs yet.  */
  if (dwarf2_per_objfile->signatured_types == NULL)
    {
      dwarf2_per_objfile->signatured_types
	= allocate_signatured_type_table (objfile);
    }

  /* We only ever need to read in one copy of a signatured type.
     Use the global signatured_types array to do our own comdat-folding
     of types.  If this is the first time we're reading this TU, and
     the TU has an entry in .gdb_index, replace the recorded data from
     .gdb_index with this TU.  */

  find_sig_entry.signature = sig;
  slot = htab_find_slot (dwarf2_per_objfile->signatured_types,
			 &find_sig_entry, INSERT);
  sig_entry = (struct signatured_type *) *slot;

  /* We can get here with the TU already read, *or* in the process of being
     read.  Don't reassign the global entry to point to this DWO if that's
     the case.  Also note that if the TU is already being read, it may not
     have come from a DWO, the program may be a mix of Fission-compiled
     code and non-Fission-compiled code.  */

  /* Have we already tried to read this TU?
     Note: sig_entry can be NULL if the skeleton TU was removed (thus it
     needn't exist in the global table yet).  */
  if (sig_entry != NULL && sig_entry->per_cu.tu_read)
    return sig_entry;

  /* Note: cu->dwo_unit is the dwo_unit that references this TU, not the
     dwo_unit of the TU itself.  */
  dwo_file = cu->dwo_unit->dwo_file;

  /* Ok, this is the first time we're reading this TU.  */
  if (dwo_file->tus == NULL)
    return NULL;
  find_dwo_entry.signature = sig;
  dwo_entry = (struct dwo_unit *) htab_find (dwo_file->tus, &find_dwo_entry);
  if (dwo_entry == NULL)
    return NULL;

  /* If the global table doesn't have an entry for this TU, add one.  */
  if (sig_entry == NULL)
    sig_entry = add_type_unit (dwarf2_per_objfile, sig, slot);

  fill_in_sig_entry_from_dwo_entry (dwarf2_per_objfile, sig_entry, dwo_entry);
  sig_entry->per_cu.tu_read = 1;
  return sig_entry;
}

/* Subroutine of lookup_signatured_type.
   Look up the type for signature SIG, and if we can't find SIG in .gdb_index
   then try the DWP file.  If the TU stub (skeleton) has been removed then
   it won't be in .gdb_index.  */

static struct signatured_type *
lookup_dwp_signatured_type (struct dwarf2_cu *cu, ULONGEST sig)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwp_file *dwp_file = get_dwp_file (dwarf2_per_objfile);
  struct dwo_unit *dwo_entry;
  struct signatured_type find_sig_entry, *sig_entry;
  void **slot;
  unsigned int is_debug_types = 1;

  gdb_assert (cu->dwo_unit && dwarf2_per_objfile->using_index);
  gdb_assert (dwp_file != NULL);

  /* If TU skeletons have been removed then we may not have read in any
     TUs yet.  */
  if (dwarf2_per_objfile->signatured_types == NULL)
    {
      dwarf2_per_objfile->signatured_types
	= allocate_signatured_type_table (objfile);
    }

  find_sig_entry.signature = sig;
  slot = htab_find_slot (dwarf2_per_objfile->signatured_types,
			 &find_sig_entry, INSERT);
  sig_entry = (struct signatured_type *) *slot;

  /* Have we already tried to read this TU?
     Note: sig_entry can be NULL if the skeleton TU was removed (thus it
     needn't exist in the global table yet).  */
  if (sig_entry != NULL)
    return sig_entry;

  if (dwp_file->tus == NULL)
    return NULL;

  dwo_entry = lookup_dwo_unit_in_dwp (dwarf2_per_objfile, dwp_file, NULL,
				      sig, is_debug_types);
  if (dwo_entry == NULL)
    return NULL;

  sig_entry = add_type_unit (dwarf2_per_objfile, sig, slot);
  fill_in_sig_entry_from_dwo_entry (dwarf2_per_objfile, sig_entry, dwo_entry);

  return sig_entry;
}

/* Lookup a signature based type for DW_FORM_ref_sig8.
   Returns NULL if signature SIG is not present in the table.
   It is up to the caller to complain about this.  */

static struct signatured_type *
lookup_signatured_type (struct dwarf2_cu *cu, ULONGEST sig)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;

  if (cu->dwo_unit
      && dwarf2_per_objfile->using_index)
    {
      /* We're in a DWO/DWP file, and we're using .gdb_index.
	 These cases require special processing.  */
      if (get_dwp_file (dwarf2_per_objfile) == NULL)
	return lookup_dwo_signatured_type (cu, sig);
      else
	return lookup_dwp_signatured_type (cu, sig);
    }
  else
    {
      struct signatured_type find_entry, *entry;

      if (dwarf2_per_objfile->signatured_types == NULL)
	return NULL;
      find_entry.signature = sig;
      entry = ((struct signatured_type *)
	       htab_find (dwarf2_per_objfile->signatured_types, &find_entry));
      return entry;
    }
}

/* Return the address base of the compile unit, which, if exists, is stored
   either at the attribute DW_AT_GNU_addr_base, or DW_AT_addr_base.  */
static gdb::optional<ULONGEST>
lookup_addr_base (struct die_info *comp_unit_die)
{
  struct attribute *attr;
  attr = dwarf2_attr_no_follow (comp_unit_die, DW_AT_addr_base);
  if (attr == nullptr)
    attr = dwarf2_attr_no_follow (comp_unit_die, DW_AT_GNU_addr_base);
  if (attr == nullptr)
    return gdb::optional<ULONGEST> ();
  return DW_UNSND (attr);
}

/* Return range lists base of the compile unit, which, if exists, is stored
   either at the attribute DW_AT_rnglists_base or DW_AT_GNU_ranges_base.  */
static gdb::optional<ULONGEST>
lookup_ranges_base (struct die_info *comp_unit_die)
{
  struct attribute *attr;
  attr = dwarf2_attr_no_follow (comp_unit_die, DW_AT_rnglists_base);
  if (attr == nullptr)
    attr = dwarf2_attr_no_follow (comp_unit_die, DW_AT_GNU_ranges_base);
  if (attr == nullptr)
    return gdb::optional<ULONGEST> ();
  return DW_UNSND (attr);
}

/* Calculate the offset into the .debug_rnglists or .debug_ranges section to
   read the range for an DW_AT_ranges attribute.  For DW_FORM_rnglistx
   introduced in DWARF 5, the ranges base attribute (DW_AT_rnglists_base or
   DW_AT_GNU_ranges_base) have already been taken into account. For other forms,
   the range base should be added to the form value. DW_TAG_compile_unit does
   not need ranges base, per existing comments.  */
static ULONGEST
calculate_ranges_offset(struct dwarf2_cu &cu, struct attribute &attr,
			dwarf_tag tag)
{
  if (attr.name != DW_AT_ranges)
      error(_("Internal error, wrong attribute sent to "
	      "calculate_ranges_offset"));
  bool need_ranges_base = true;
  /* DW_AT_rnglists_base does not apply to DIEs from the DWO skeleton.
     We take advantage of the fact that DW_AT_ranges does not appear
     in DW_TAG_compile_unit of DWO files.  */
  if (tag == DW_TAG_compile_unit)
    need_ranges_base = false;
  if (attr.form == DW_FORM_rnglistx)
    need_ranges_base = false;
  ULONGEST result = DW_UNSND (&attr);
  if (need_ranges_base)
    result += cu.ranges_base;
  return result;
}

/* Low level DIE reading support.  */

/* Initialize a die_reader_specs struct from a dwarf2_cu struct.  */

static void
init_cu_die_reader (struct die_reader_specs *reader,
		    struct dwarf2_cu *cu,
		    struct dwarf2_section_info *section,
		    struct dwo_file *dwo_file,
		    struct abbrev_table *abbrev_table)
{
  gdb_assert (section->readin && section->buffer != NULL);
  reader->abfd = get_section_bfd_owner (section);
  reader->cu = cu;
  reader->dwo_file = dwo_file;
  reader->die_section = section;
  reader->buffer = section->buffer;
  reader->buffer_end = section->buffer + section->size;
  reader->comp_dir = NULL;
  reader->abbrev_table = abbrev_table;
}

/* Subroutine of init_cutu_and_read_dies to simplify it.
   Read in the rest of a CU/TU top level DIE from DWO_UNIT.
   There's just a lot of work to do, and init_cutu_and_read_dies is big enough
   already.

   STUB_COMP_UNIT_DIE is for the stub DIE, we copy over certain attributes
   from it to the DIE in the DWO.  If NULL we are skipping the stub.
   STUB_COMP_DIR is similar to STUB_COMP_UNIT_DIE: When reading a TU directly
   from the DWO file, bypassing the stub, it contains the DW_AT_comp_dir
   attribute of the referencing CU.  At most one of STUB_COMP_UNIT_DIE and
   STUB_COMP_DIR may be non-NULL.
   *RESULT_READER,*RESULT_INFO_PTR,*RESULT_COMP_UNIT_DIE,*RESULT_HAS_CHILDREN
   are filled in with the info of the DIE from the DWO file.
   *RESULT_DWO_ABBREV_TABLE will be filled in with the abbrev table allocated
   from the dwo.  Since *RESULT_READER references this abbrev table, it must be
   kept around for at least as long as *RESULT_READER.

   The result is non-zero if a valid (non-dummy) DIE was found.  */

static int
read_cutu_die_from_dwo (struct dwarf2_per_cu_data *this_cu,
			struct dwo_unit *dwo_unit,
			struct die_info *stub_comp_unit_die,
			const char *stub_comp_dir,
			struct die_reader_specs *result_reader,
			const gdb_byte **result_info_ptr,
			struct die_info **result_comp_unit_die,
			int *result_has_children,
			abbrev_table_up *result_dwo_abbrev_table)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_cu *cu = this_cu->cu;
  bfd *abfd;
  const gdb_byte *begin_info_ptr, *info_ptr;
  struct attribute *comp_dir, *stmt_list, *low_pc, *high_pc, *ranges;
  int i,num_extra_attrs;
  struct dwarf2_section_info *dwo_abbrev_section;
  struct die_info *comp_unit_die;

  /* At most one of these may be provided.  */
  gdb_assert ((stub_comp_unit_die != NULL) + (stub_comp_dir != NULL) <= 1);

  /* These attributes aren't processed until later:
     DW_AT_stmt_list, DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges.
     DW_AT_comp_dir is used now, to find the DWO file, but it is also
     referenced later.  However, these attributes are found in the stub
     which we won't have later.  In order to not impose this complication
     on the rest of the code, we read them here and copy them to the
     DWO CU/TU die.  */

  stmt_list = NULL;
  low_pc = NULL;
  high_pc = NULL;
  ranges = NULL;
  comp_dir = NULL;

  if (stub_comp_unit_die != NULL)
    {
      /* For TUs in DWO files, the DW_AT_stmt_list attribute lives in the
	 DWO file.  */
      if (! this_cu->is_debug_types)
	stmt_list = dwarf2_attr (stub_comp_unit_die, DW_AT_stmt_list, cu);
      low_pc = dwarf2_attr (stub_comp_unit_die, DW_AT_low_pc, cu);
      high_pc = dwarf2_attr (stub_comp_unit_die, DW_AT_high_pc, cu);
      ranges = dwarf2_attr (stub_comp_unit_die, DW_AT_ranges, cu);
      comp_dir = dwarf2_attr (stub_comp_unit_die, DW_AT_comp_dir, cu);

      cu->addr_base = lookup_addr_base (stub_comp_unit_die);

      /* There should be a DW_AT_rnglists_base (DW_AT_GNU_ranges_base) attribute
	 here (if needed). We need the value before we can process
	 DW_AT_ranges.  */
      auto maybe_ranges_base = lookup_ranges_base (stub_comp_unit_die);
      if (maybe_ranges_base.has_value ())
        cu->ranges_base = *maybe_ranges_base;
    }
  else if (stub_comp_dir != NULL)
    {
      /* Reconstruct the comp_dir attribute to simplify the code below.  */
      comp_dir = XOBNEW (&cu->comp_unit_obstack, struct attribute);
      comp_dir->name = DW_AT_comp_dir;
      comp_dir->form = DW_FORM_string;
      DW_STRING_IS_CANONICAL (comp_dir) = 0;
      DW_STRING (comp_dir) = stub_comp_dir;
    }

  /* Set up for reading the DWO CU/TU.  */
  cu->dwo_unit = dwo_unit;
  dwarf2_section_info *section = dwo_unit->section;
  dwarf2_read_section (objfile, section);
  abfd = get_section_bfd_owner (section);
  begin_info_ptr = info_ptr = (section->buffer
			       + to_underlying (dwo_unit->sect_off));
  dwo_abbrev_section = &dwo_unit->dwo_file->sections.abbrev;

  if (this_cu->is_debug_types)
    {
      struct signatured_type *sig_type = (struct signatured_type *) this_cu;

      info_ptr = read_and_check_comp_unit_head (dwarf2_per_objfile,
						&cu->header, section,
						dwo_abbrev_section,
						info_ptr, rcuh_kind::TYPE);
      /* This is not an assert because it can be caused by bad debug info.  */
      if (sig_type->signature != cu->header.signature)
	{
	  error (_("Dwarf Error: signature mismatch %s vs %s while reading"
		   " TU at offset %s [in module %s]"),
		 hex_string (sig_type->signature),
		 hex_string (cu->header.signature),
		 sect_offset_str (dwo_unit->sect_off),
		 bfd_get_filename (abfd));
	}
      gdb_assert (dwo_unit->sect_off == cu->header.sect_off);
      /* For DWOs coming from DWP files, we don't know the CU length
	 nor the type's offset in the TU until now.  */
      dwo_unit->length = get_cu_length (&cu->header);
      dwo_unit->type_offset_in_tu = cu->header.type_cu_offset_in_tu;

      /* Establish the type offset that can be used to lookup the type.
	 For DWO files, we don't know it until now.  */
      sig_type->type_offset_in_section
	= dwo_unit->sect_off + to_underlying (dwo_unit->type_offset_in_tu);
    }
  else
    {
      info_ptr = read_and_check_comp_unit_head (dwarf2_per_objfile,
						&cu->header, section,
						dwo_abbrev_section,
						info_ptr, rcuh_kind::COMPILE);
      gdb_assert (dwo_unit->sect_off == cu->header.sect_off);
      /* For DWOs coming from DWP files, we don't know the CU length
	 until now.  */
      dwo_unit->length = get_cu_length (&cu->header);
    }

  *result_dwo_abbrev_table
    = abbrev_table_read_table (dwarf2_per_objfile, dwo_abbrev_section,
			       cu->header.abbrev_sect_off);
  init_cu_die_reader (result_reader, cu, section, dwo_unit->dwo_file,
		      result_dwo_abbrev_table->get ());

  /* Read in the die, but leave space to copy over the attributes
     from the stub.  This has the benefit of simplifying the rest of
     the code - all the work to maintain the illusion of a single
     DW_TAG_{compile,type}_unit DIE is done here.  */
  num_extra_attrs = ((stmt_list != NULL)
		     + (low_pc != NULL)
		     + (high_pc != NULL)
		     + (ranges != NULL)
		     + (comp_dir != NULL));
  info_ptr = read_full_die_1 (result_reader, result_comp_unit_die, info_ptr,
			      result_has_children, num_extra_attrs);

  /* Copy over the attributes from the stub to the DIE we just read in.  */
  comp_unit_die = *result_comp_unit_die;
  i = comp_unit_die->num_attrs;
  if (stmt_list != NULL)
    comp_unit_die->attrs[i++] = *stmt_list;
  if (low_pc != NULL)
    comp_unit_die->attrs[i++] = *low_pc;
  if (high_pc != NULL)
    comp_unit_die->attrs[i++] = *high_pc;
  if (ranges != NULL)
    comp_unit_die->attrs[i++] = *ranges;
  if (comp_dir != NULL)
    comp_unit_die->attrs[i++] = *comp_dir;
  comp_unit_die->num_attrs += num_extra_attrs;

  if (dwarf_die_debug)
    {
      fprintf_unfiltered (gdb_stdlog,
			  "Read die from %s@0x%x of %s:\n",
			  get_section_name (section),
			  (unsigned) (begin_info_ptr - section->buffer),
			  bfd_get_filename (abfd));
      dump_die (comp_unit_die, dwarf_die_debug);
    }

  /* Save the comp_dir attribute.  If there is no DWP file then we'll read
     TUs by skipping the stub and going directly to the entry in the DWO file.
     However, skipping the stub means we won't get DW_AT_comp_dir, so we have
     to get it via circuitous means.  Blech.  */
  if (comp_dir != NULL)
    result_reader->comp_dir = DW_STRING (comp_dir);

  /* Skip dummy compilation units.  */
  if (info_ptr >= begin_info_ptr + dwo_unit->length
      || peek_abbrev_code (abfd, info_ptr) == 0)
    return 0;

  *result_info_ptr = info_ptr;
  return 1;
}

/* Return the signature of the compile unit, if found. In DWARF 4 and before,
   the signature is in the DW_AT_GNU_dwo_id attribute. In DWARF 5 and later, the
   signature is part of the header.  */
static gdb::optional<ULONGEST>
lookup_dwo_id (struct dwarf2_cu *cu, struct die_info* comp_unit_die)
{
  if (cu->header.version >= 5)
    return cu->header.signature;
  struct attribute *attr;
  attr = dwarf2_attr (comp_unit_die, DW_AT_GNU_dwo_id, cu);
  if (attr == nullptr)
    return gdb::optional<ULONGEST> ();
  return DW_UNSND (attr);
}

/* Subroutine of init_cutu_and_read_dies to simplify it.
   Look up the DWO unit specified by COMP_UNIT_DIE of THIS_CU.
   Returns NULL if the specified DWO unit cannot be found.  */

static struct dwo_unit *
lookup_dwo_unit (struct dwarf2_per_cu_data *this_cu,
		 struct die_info *comp_unit_die)
{
  struct dwarf2_cu *cu = this_cu->cu;
  struct dwo_unit *dwo_unit;
  const char *comp_dir, *dwo_name;

  gdb_assert (cu != NULL);

  /* Yeah, we look dwo_name up again, but it simplifies the code.  */
  dwo_name = dwarf2_dwo_name (comp_unit_die, cu);
  comp_dir = dwarf2_string_attr (comp_unit_die, DW_AT_comp_dir, cu);

  if (this_cu->is_debug_types)
    {
      struct signatured_type *sig_type;

      /* Since this_cu is the first member of struct signatured_type,
	 we can go from a pointer to one to a pointer to the other.  */
      sig_type = (struct signatured_type *) this_cu;
      dwo_unit = lookup_dwo_type_unit (sig_type, dwo_name, comp_dir);
    }
  else
    {
      gdb::optional<ULONGEST> signature = lookup_dwo_id (cu, comp_unit_die);
      if (!signature.has_value ())
	error (_("Dwarf Error: missing dwo_id for dwo_name %s"
		 " [in module %s]"),
	       dwo_name, objfile_name (this_cu->dwarf2_per_objfile->objfile));
      dwo_unit = lookup_dwo_comp_unit (this_cu, dwo_name, comp_dir,
				       *signature);
    }

  return dwo_unit;
}

/* Subroutine of init_cutu_and_read_dies to simplify it.
   See it for a description of the parameters.
   Read a TU directly from a DWO file, bypassing the stub.  */

static void
init_tu_and_read_dwo_dies (struct dwarf2_per_cu_data *this_cu,
			   int use_existing_cu, int keep,
			   die_reader_func_ftype *die_reader_func,
			   void *data)
{
  std::unique_ptr<dwarf2_cu> new_cu;
  struct signatured_type *sig_type;
  struct die_reader_specs reader;
  const gdb_byte *info_ptr;
  struct die_info *comp_unit_die;
  int has_children;
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_cu->dwarf2_per_objfile;

  /* Verify we can do the following downcast, and that we have the
     data we need.  */
  gdb_assert (this_cu->is_debug_types && this_cu->reading_dwo_directly);
  sig_type = (struct signatured_type *) this_cu;
  gdb_assert (sig_type->dwo_unit != NULL);

  if (use_existing_cu && this_cu->cu != NULL)
    {
      gdb_assert (this_cu->cu->dwo_unit == sig_type->dwo_unit);
      /* There's no need to do the rereading_dwo_cu handling that
	 init_cutu_and_read_dies does since we don't read the stub.  */
    }
  else
    {
      /* If !use_existing_cu, this_cu->cu must be NULL.  */
      gdb_assert (this_cu->cu == NULL);
      new_cu.reset (new dwarf2_cu (this_cu));
    }

  /* A future optimization, if needed, would be to use an existing
     abbrev table.  When reading DWOs with skeletonless TUs, all the TUs
     could share abbrev tables.  */

  /* The abbreviation table used by READER, this must live at least as long as
     READER.  */
  abbrev_table_up dwo_abbrev_table;

  if (read_cutu_die_from_dwo (this_cu, sig_type->dwo_unit,
			      NULL /* stub_comp_unit_die */,
			      sig_type->dwo_unit->dwo_file->comp_dir,
			      &reader, &info_ptr,
			      &comp_unit_die, &has_children,
			      &dwo_abbrev_table) == 0)
    {
      /* Dummy die.  */
      return;
    }

  /* All the "real" work is done here.  */
  die_reader_func (&reader, info_ptr, comp_unit_die, has_children, data);

  /* This duplicates the code in init_cutu_and_read_dies,
     but the alternative is making the latter more complex.
     This function is only for the special case of using DWO files directly:
     no point in overly complicating the general case just to handle this.  */
  if (new_cu != NULL && keep)
    {
      /* Link this CU into read_in_chain.  */
      this_cu->cu->read_in_chain = dwarf2_per_objfile->read_in_chain;
      dwarf2_per_objfile->read_in_chain = this_cu;
      /* The chain owns it now.  */
      new_cu.release ();
    }
}

/* Initialize a CU (or TU) and read its DIEs.
   If the CU defers to a DWO file, read the DWO file as well.

   ABBREV_TABLE, if non-NULL, is the abbreviation table to use.
   Otherwise the table specified in the comp unit header is read in and used.
   This is an optimization for when we already have the abbrev table.

   If USE_EXISTING_CU is non-zero, and THIS_CU->cu is non-NULL, then use it.
   Otherwise, a new CU is allocated with xmalloc.

   If KEEP is non-zero, then if we allocated a dwarf2_cu we add it to
   read_in_chain.  Otherwise the dwarf2_cu data is freed at the end.

   WARNING: If THIS_CU is a "dummy CU" (used as filler by the incremental
   linker) then DIE_READER_FUNC will not get called.  */

static void
init_cutu_and_read_dies (struct dwarf2_per_cu_data *this_cu,
			 struct abbrev_table *abbrev_table,
			 int use_existing_cu, int keep,
			 bool skip_partial,
			 die_reader_func_ftype *die_reader_func,
			 void *data)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_section_info *section = this_cu->section;
  bfd *abfd = get_section_bfd_owner (section);
  struct dwarf2_cu *cu;
  const gdb_byte *begin_info_ptr, *info_ptr;
  struct die_reader_specs reader;
  struct die_info *comp_unit_die;
  int has_children;
  struct signatured_type *sig_type = NULL;
  struct dwarf2_section_info *abbrev_section;
  /* Non-zero if CU currently points to a DWO file and we need to
     reread it.  When this happens we need to reread the skeleton die
     before we can reread the DWO file (this only applies to CUs, not TUs).  */
  int rereading_dwo_cu = 0;

  if (dwarf_die_debug)
    fprintf_unfiltered (gdb_stdlog, "Reading %s unit at offset %s\n",
			this_cu->is_debug_types ? "type" : "comp",
			sect_offset_str (this_cu->sect_off));

  if (use_existing_cu)
    gdb_assert (keep);

  /* If we're reading a TU directly from a DWO file, including a virtual DWO
     file (instead of going through the stub), short-circuit all of this.  */
  if (this_cu->reading_dwo_directly)
    {
      /* Narrow down the scope of possibilities to have to understand.  */
      gdb_assert (this_cu->is_debug_types);
      gdb_assert (abbrev_table == NULL);
      init_tu_and_read_dwo_dies (this_cu, use_existing_cu, keep,
				 die_reader_func, data);
      return;
    }

  /* This is cheap if the section is already read in.  */
  dwarf2_read_section (objfile, section);

  begin_info_ptr = info_ptr = section->buffer + to_underlying (this_cu->sect_off);

  abbrev_section = get_abbrev_section_for_cu (this_cu);

  std::unique_ptr<dwarf2_cu> new_cu;
  if (use_existing_cu && this_cu->cu != NULL)
    {
      cu = this_cu->cu;
      /* If this CU is from a DWO file we need to start over, we need to
	 refetch the attributes from the skeleton CU.
	 This could be optimized by retrieving those attributes from when we
	 were here the first time: the previous comp_unit_die was stored in
	 comp_unit_obstack.  But there's no data yet that we need this
	 optimization.  */
      if (cu->dwo_unit != NULL)
	rereading_dwo_cu = 1;
    }
  else
    {
      /* If !use_existing_cu, this_cu->cu must be NULL.  */
      gdb_assert (this_cu->cu == NULL);
      new_cu.reset (new dwarf2_cu (this_cu));
      cu = new_cu.get ();
    }

  /* Get the header.  */
  if (to_underlying (cu->header.first_die_cu_offset) != 0 && !rereading_dwo_cu)
    {
      /* We already have the header, there's no need to read it in again.  */
      info_ptr += to_underlying (cu->header.first_die_cu_offset);
    }
  else
    {
      if (this_cu->is_debug_types)
	{
	  info_ptr = read_and_check_comp_unit_head (dwarf2_per_objfile,
						    &cu->header, section,
						    abbrev_section, info_ptr,
						    rcuh_kind::TYPE);

	  /* Since per_cu is the first member of struct signatured_type,
	     we can go from a pointer to one to a pointer to the other.  */
	  sig_type = (struct signatured_type *) this_cu;
	  gdb_assert (sig_type->signature == cu->header.signature);
	  gdb_assert (sig_type->type_offset_in_tu
		      == cu->header.type_cu_offset_in_tu);
	  gdb_assert (this_cu->sect_off == cu->header.sect_off);

	  /* LENGTH has not been set yet for type units if we're
	     using .gdb_index.  */
	  this_cu->length = get_cu_length (&cu->header);

	  /* Establish the type offset that can be used to lookup the type.  */
	  sig_type->type_offset_in_section =
	    this_cu->sect_off + to_underlying (sig_type->type_offset_in_tu);

	  this_cu->dwarf_version = cu->header.version;
	}
      else
	{
	  info_ptr = read_and_check_comp_unit_head (dwarf2_per_objfile,
						    &cu->header, section,
						    abbrev_section,
						    info_ptr,
						    rcuh_kind::COMPILE);

	  gdb_assert (this_cu->sect_off == cu->header.sect_off);
	  gdb_assert (this_cu->length == get_cu_length (&cu->header));
	  this_cu->dwarf_version = cu->header.version;
	}
    }

  /* Skip dummy compilation units.  */
  if (info_ptr >= begin_info_ptr + this_cu->length
      || peek_abbrev_code (abfd, info_ptr) == 0)
    return;

  /* If we don't have them yet, read the abbrevs for this compilation unit.
     And if we need to read them now, make sure they're freed when we're
     done (own the table through ABBREV_TABLE_HOLDER).  */
  abbrev_table_up abbrev_table_holder;
  if (abbrev_table != NULL)
    gdb_assert (cu->header.abbrev_sect_off == abbrev_table->sect_off);
  else
    {
      abbrev_table_holder
	= abbrev_table_read_table (dwarf2_per_objfile, abbrev_section,
				   cu->header.abbrev_sect_off);
      abbrev_table = abbrev_table_holder.get ();
    }

  /* Read the top level CU/TU die.  */
  init_cu_die_reader (&reader, cu, section, NULL, abbrev_table);
  info_ptr = read_full_die (&reader, &comp_unit_die, info_ptr, &has_children);

  if (skip_partial && comp_unit_die->tag == DW_TAG_partial_unit)
    return;

  /* If we are in a DWO stub, process it and then read in the "real" CU/TU
     from the DWO file.  read_cutu_die_from_dwo will allocate the abbreviation
     table from the DWO file and pass the ownership over to us.  It will be
     referenced from READER, so we must make sure to free it after we're done
     with READER.

     Note that if USE_EXISTING_OK != 0, and THIS_CU->cu already contains a
     DWO CU, that this test will fail (the attribute will not be present).  */
  const char *dwo_name = dwarf2_dwo_name (comp_unit_die, cu);
  abbrev_table_up dwo_abbrev_table;
  if (dwo_name != nullptr)
    {
      struct dwo_unit *dwo_unit;
      struct die_info *dwo_comp_unit_die;

      if (has_children)
	{
	  complaint (_("compilation unit with DW_AT_GNU_dwo_name"
		       " has children (offset %s) [in module %s]"),
		     sect_offset_str (this_cu->sect_off),
		     bfd_get_filename (abfd));
	}
      dwo_unit = lookup_dwo_unit (this_cu, comp_unit_die);
      if (dwo_unit != NULL)
	{
	  if (read_cutu_die_from_dwo (this_cu, dwo_unit,
				      comp_unit_die, NULL,
				      &reader, &info_ptr,
				      &dwo_comp_unit_die, &has_children,
				      &dwo_abbrev_table) == 0)
	    {
	      /* Dummy die.  */
	      return;
	    }
          if (dwarf2_attr_no_follow (comp_unit_die, DW_AT_ranges))
            {
              this_cu->cu->cu_ranges_from_skeleton = 1;
            }
	  comp_unit_die = dwo_comp_unit_die;
	}
      else
	{
	  /* Yikes, we couldn't find the rest of the DIE, we only have
	     the stub.  A complaint has already been logged.  There's
	     not much more we can do except pass on the stub DIE to
	     die_reader_func.  We don't want to throw an error on bad
	     debug info.  */
	}
    }

  /* All of the above is setup for this call.  Yikes.  */
  die_reader_func (&reader, info_ptr, comp_unit_die, has_children, data);

  /* Done, clean up.  */
  if (new_cu != NULL && keep)
    {
      /* Link this CU into read_in_chain.  */
      this_cu->cu->read_in_chain = dwarf2_per_objfile->read_in_chain;
      dwarf2_per_objfile->read_in_chain = this_cu;
      /* The chain owns it now.  */
      new_cu.release ();
    }
}

/* Read CU/TU THIS_CU but do not follow DW_AT_GNU_dwo_name (DW_AT_dwo_name)
   if present. DWO_FILE, if non-NULL, is the DWO file to read (the caller is
   assumed to have already done the lookup to find the DWO file).

   The caller is required to fill in THIS_CU->section, THIS_CU->offset, and
   THIS_CU->is_debug_types, but nothing else.

   We fill in THIS_CU->length.

   WARNING: If THIS_CU is a "dummy CU" (used as filler by the incremental
   linker) then DIE_READER_FUNC will not get called.

   THIS_CU->cu is always freed when done.
   This is done in order to not leave THIS_CU->cu in a state where we have
   to care whether it refers to the "main" CU or the DWO CU.

   When parent_cu is passed, it is used to provide a default value for
   str_offsets_base and addr_base from the parent.  */

static void
init_cutu_and_read_dies_no_follow (struct dwarf2_per_cu_data *this_cu,
				   struct dwarf2_cu *parent_cu,
				   struct dwo_file *dwo_file,
				   die_reader_func_ftype *die_reader_func,
				   void *data)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_section_info *section = this_cu->section;
  bfd *abfd = get_section_bfd_owner (section);
  struct dwarf2_section_info *abbrev_section;
  const gdb_byte *begin_info_ptr, *info_ptr;
  struct die_reader_specs reader;
  struct die_info *comp_unit_die;
  int has_children;

  if (dwarf_die_debug)
    fprintf_unfiltered (gdb_stdlog, "Reading %s unit at offset %s\n",
			this_cu->is_debug_types ? "type" : "comp",
			sect_offset_str (this_cu->sect_off));

  gdb_assert (this_cu->cu == NULL);

  abbrev_section = (dwo_file != NULL
		    ? &dwo_file->sections.abbrev
		    : get_abbrev_section_for_cu (this_cu));

  /* This is cheap if the section is already read in.  */
  dwarf2_read_section (objfile, section);

  struct dwarf2_cu cu (this_cu);

  begin_info_ptr = info_ptr = section->buffer + to_underlying (this_cu->sect_off);
  info_ptr = read_and_check_comp_unit_head (dwarf2_per_objfile,
					    &cu.header, section,
					    abbrev_section, info_ptr,
					    (this_cu->is_debug_types
					     ? rcuh_kind::TYPE
					     : rcuh_kind::COMPILE));

  if (parent_cu != nullptr)
    {
      cu.str_offsets_base = parent_cu->str_offsets_base;
      cu.addr_base = parent_cu->addr_base;
      cu.ranges_base = parent_cu->ranges_base;
    }
  this_cu->length = get_cu_length (&cu.header);

  /* Skip dummy compilation units.  */
  if (info_ptr >= begin_info_ptr + this_cu->length
      || peek_abbrev_code (abfd, info_ptr) == 0)
    return;

  abbrev_table_up abbrev_table
    = abbrev_table_read_table (dwarf2_per_objfile, abbrev_section,
			       cu.header.abbrev_sect_off);

  init_cu_die_reader (&reader, &cu, section, dwo_file, abbrev_table.get ());
  info_ptr = read_full_die (&reader, &comp_unit_die, info_ptr, &has_children);

  die_reader_func (&reader, info_ptr, comp_unit_die, has_children, data);
}

/* Read a CU/TU, except that this does not look for DW_AT_GNU_dwo_name
   (DW_AT_dwo_name) and does not lookup the specified DWO file.
   This cannot be used to read DWO files.

   THIS_CU->cu is always freed when done.
   This is done in order to not leave THIS_CU->cu in a state where we have
   to care whether it refers to the "main" CU or the DWO CU.
   We can revisit this if the data shows there's a performance issue.  */

static void
init_cutu_and_read_dies_simple (struct dwarf2_per_cu_data *this_cu,
				die_reader_func_ftype *die_reader_func,
				void *data)
{
  init_cutu_and_read_dies_no_follow (this_cu, NULL, NULL, die_reader_func, data);
}

/* Type Unit Groups.

   Type Unit Groups are a way to collapse the set of all TUs (type units) into
   a more manageable set.  The grouping is done by DW_AT_stmt_list entry
   so that all types coming from the same compilation (.o file) are grouped
   together.  A future step could be to put the types in the same symtab as
   the CU the types ultimately came from.  */

static hashval_t
hash_type_unit_group (const void *item)
{
  const struct type_unit_group *tu_group
    = (const struct type_unit_group *) item;

  return hash_stmt_list_entry (&tu_group->hash);
}

static int
eq_type_unit_group (const void *item_lhs, const void *item_rhs)
{
  const struct type_unit_group *lhs = (const struct type_unit_group *) item_lhs;
  const struct type_unit_group *rhs = (const struct type_unit_group *) item_rhs;

  return eq_stmt_list_entry (&lhs->hash, &rhs->hash);
}

/* Allocate a hash table for type unit groups.  */

static htab_t
allocate_type_unit_groups_table (struct objfile *objfile)
{
  return htab_create_alloc_ex (3,
			       hash_type_unit_group,
			       eq_type_unit_group,
			       NULL,
			       &objfile->objfile_obstack,
			       hashtab_obstack_allocate,
			       dummy_obstack_deallocate);
}

/* Type units that don't have DW_AT_stmt_list are grouped into their own
   partial symtabs.  We combine several TUs per psymtab to not let the size
   of any one psymtab grow too big.  */
#define NO_STMT_LIST_TYPE_UNIT_PSYMTAB (1 << 31)
#define NO_STMT_LIST_TYPE_UNIT_PSYMTAB_SIZE 10

/* Helper routine for get_type_unit_group.
   Create the type_unit_group object used to hold one or more TUs.  */

static struct type_unit_group *
create_type_unit_group (struct dwarf2_cu *cu, sect_offset line_offset_struct)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_per_cu_data *per_cu;
  struct type_unit_group *tu_group;

  tu_group = OBSTACK_ZALLOC (&objfile->objfile_obstack,
			     struct type_unit_group);
  per_cu = &tu_group->per_cu;
  per_cu->dwarf2_per_objfile = dwarf2_per_objfile;

  if (dwarf2_per_objfile->using_index)
    {
      per_cu->v.quick = OBSTACK_ZALLOC (&objfile->objfile_obstack,
					struct dwarf2_per_cu_quick_data);
    }
  else
    {
      unsigned int line_offset = to_underlying (line_offset_struct);
      struct partial_symtab *pst;
      std::string name;

      /* Give the symtab a useful name for debug purposes.  */
      if ((line_offset & NO_STMT_LIST_TYPE_UNIT_PSYMTAB) != 0)
	name = string_printf ("<type_units_%d>",
			      (line_offset & ~NO_STMT_LIST_TYPE_UNIT_PSYMTAB));
      else
	name = string_printf ("<type_units_at_0x%x>", line_offset);

      pst = create_partial_symtab (per_cu, name.c_str ());
      pst->anonymous = 1;
    }

  tu_group->hash.dwo_unit = cu->dwo_unit;
  tu_group->hash.line_sect_off = line_offset_struct;

  return tu_group;
}

/* Look up the type_unit_group for type unit CU, and create it if necessary.
   STMT_LIST is a DW_AT_stmt_list attribute.  */

static struct type_unit_group *
get_type_unit_group (struct dwarf2_cu *cu, const struct attribute *stmt_list)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct tu_stats *tu_stats = &dwarf2_per_objfile->tu_stats;
  struct type_unit_group *tu_group;
  void **slot;
  unsigned int line_offset;
  struct type_unit_group type_unit_group_for_lookup;

  if (dwarf2_per_objfile->type_unit_groups == NULL)
    {
      dwarf2_per_objfile->type_unit_groups =
	allocate_type_unit_groups_table (dwarf2_per_objfile->objfile);
    }

  /* Do we need to create a new group, or can we use an existing one?  */

  if (stmt_list)
    {
      line_offset = DW_UNSND (stmt_list);
      ++tu_stats->nr_symtab_sharers;
    }
  else
    {
      /* Ugh, no stmt_list.  Rare, but we have to handle it.
	 We can do various things here like create one group per TU or
	 spread them over multiple groups to split up the expansion work.
	 To avoid worst case scenarios (too many groups or too large groups)
	 we, umm, group them in bunches.  */
      line_offset = (NO_STMT_LIST_TYPE_UNIT_PSYMTAB
		     | (tu_stats->nr_stmt_less_type_units
			/ NO_STMT_LIST_TYPE_UNIT_PSYMTAB_SIZE));
      ++tu_stats->nr_stmt_less_type_units;
    }

  type_unit_group_for_lookup.hash.dwo_unit = cu->dwo_unit;
  type_unit_group_for_lookup.hash.line_sect_off = (sect_offset) line_offset;
  slot = htab_find_slot (dwarf2_per_objfile->type_unit_groups,
			 &type_unit_group_for_lookup, INSERT);
  if (*slot != NULL)
    {
      tu_group = (struct type_unit_group *) *slot;
      gdb_assert (tu_group != NULL);
    }
  else
    {
      sect_offset line_offset_struct = (sect_offset) line_offset;
      tu_group = create_type_unit_group (cu, line_offset_struct);
      *slot = tu_group;
      ++tu_stats->nr_symtabs;
    }

  return tu_group;
}

/* Partial symbol tables.  */

/* Create a psymtab named NAME and assign it to PER_CU.

   The caller must fill in the following details:
   dirname, textlow, texthigh.  */

static struct partial_symtab *
create_partial_symtab (struct dwarf2_per_cu_data *per_cu, const char *name)
{
  struct objfile *objfile = per_cu->dwarf2_per_objfile->objfile;
  struct partial_symtab *pst;

  pst = start_psymtab_common (objfile, name, 0);

  pst->psymtabs_addrmap_supported = 1;

  /* This is the glue that links PST into GDB's symbol API.  */
  pst->read_symtab_private = per_cu;
  pst->read_symtab = dwarf2_read_symtab;
  per_cu->v.psymtab = pst;

  return pst;
}

/* The DATA object passed to process_psymtab_comp_unit_reader has this
   type.  */

struct process_psymtab_comp_unit_data
{
  /* True if we are reading a DW_TAG_partial_unit.  */

  int want_partial_unit;

  /* The "pretend" language that is used if the CU doesn't declare a
     language.  */

  enum language pretend_language;
};

/* die_reader_func for process_psymtab_comp_unit.  */

static void
process_psymtab_comp_unit_reader (const struct die_reader_specs *reader,
				  const gdb_byte *info_ptr,
				  struct die_info *comp_unit_die,
				  int has_children,
				  void *data)
{
  struct dwarf2_cu *cu = reader->cu;
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  struct dwarf2_per_cu_data *per_cu = cu->per_cu;
  CORE_ADDR baseaddr;
  CORE_ADDR best_lowpc = 0, best_highpc = 0;
  struct partial_symtab *pst;
  enum pc_bounds_kind cu_bounds_kind;
  const char *filename;
  struct process_psymtab_comp_unit_data *info
    = (struct process_psymtab_comp_unit_data *) data;

  if (comp_unit_die->tag == DW_TAG_partial_unit && !info->want_partial_unit)
    return;

  gdb_assert (! per_cu->is_debug_types);

  prepare_one_comp_unit (cu, comp_unit_die, info->pretend_language);

  /* Allocate a new partial symbol table structure.  */
  filename = dwarf2_string_attr (comp_unit_die, DW_AT_name, cu);
  if (filename == NULL)
    filename = "";

  pst = create_partial_symtab (per_cu, filename);

  /* This must be done before calling dwarf2_build_include_psymtabs.  */
  pst->dirname = dwarf2_string_attr (comp_unit_die, DW_AT_comp_dir, cu);

  baseaddr = ANOFFSET (objfile->section_offsets,
		       SECT_OFF_TEXT (objfile));

  dwarf2_find_base_address (comp_unit_die, cu);

  /* Possibly set the default values of LOWPC and HIGHPC from
     `DW_AT_ranges'.  */
  cu_bounds_kind = dwarf2_get_pc_bounds (comp_unit_die, &best_lowpc,
					 &best_highpc, cu, pst);
  if (cu_bounds_kind == PC_BOUNDS_HIGH_LOW && best_lowpc < best_highpc)
    {
      CORE_ADDR low
	= (gdbarch_adjust_dwarf2_addr (gdbarch, best_lowpc + baseaddr)
	   - baseaddr);
      CORE_ADDR high
	= (gdbarch_adjust_dwarf2_addr (gdbarch, best_highpc + baseaddr)
	   - baseaddr - 1);
      /* Store the contiguous range if it is not empty; it can be
	 empty for CUs with no code.  */
      addrmap_set_empty (objfile->partial_symtabs->psymtabs_addrmap,
			 low, high, pst);
    }

  /* Check if comp unit has_children.
     If so, read the rest of the partial symbols from this comp unit.
     If not, there's no more debug_info for this comp unit.  */
  if (has_children)
    {
      struct partial_die_info *first_die;
      CORE_ADDR lowpc, highpc;

      lowpc = ((CORE_ADDR) -1);
      highpc = ((CORE_ADDR) 0);

      first_die = load_partial_dies (reader, info_ptr, 1);

      scan_partial_symbols (first_die, &lowpc, &highpc,
			    cu_bounds_kind <= PC_BOUNDS_INVALID, cu);

      /* If we didn't find a lowpc, set it to highpc to avoid
	 complaints from `maint check'.	 */
      if (lowpc == ((CORE_ADDR) -1))
	lowpc = highpc;

      /* If the compilation unit didn't have an explicit address range,
	 then use the information extracted from its child dies.  */
      if (cu_bounds_kind <= PC_BOUNDS_INVALID)
	{
	  best_lowpc = lowpc;
	  best_highpc = highpc;
	}
    }
  pst->set_text_low (gdbarch_adjust_dwarf2_addr (gdbarch,
						 best_lowpc + baseaddr)
		     - baseaddr);
  pst->set_text_high (gdbarch_adjust_dwarf2_addr (gdbarch,
						  best_highpc + baseaddr)
		      - baseaddr);

  end_psymtab_common (objfile, pst);

  if (!cu->per_cu->imported_symtabs_empty ())
    {
      int i;
      int len = cu->per_cu->imported_symtabs_size ();

      /* Fill in 'dependencies' here; we fill in 'users' in a
	 post-pass.  */
      pst->number_of_dependencies = len;
      pst->dependencies
	= objfile->partial_symtabs->allocate_dependencies (len);
      for (i = 0; i < len; ++i)
	{
	  pst->dependencies[i]
	    = cu->per_cu->imported_symtabs->at (i)->v.psymtab;
	}

      cu->per_cu->imported_symtabs_free ();
    }

  /* Get the list of files included in the current compilation unit,
     and build a psymtab for each of them.  */
  dwarf2_build_include_psymtabs (cu, comp_unit_die, pst);

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog,
			"Psymtab for %s unit @%s: %s - %s"
			", %d global, %d static syms\n",
			per_cu->is_debug_types ? "type" : "comp",
			sect_offset_str (per_cu->sect_off),
			paddress (gdbarch, pst->text_low (objfile)),
			paddress (gdbarch, pst->text_high (objfile)),
			pst->n_global_syms, pst->n_static_syms);
}

/* Subroutine of dwarf2_build_psymtabs_hard to simplify it.
   Process compilation unit THIS_CU for a psymtab.  */

static void
process_psymtab_comp_unit (struct dwarf2_per_cu_data *this_cu,
			   int want_partial_unit,
			   enum language pretend_language)
{
  /* If this compilation unit was already read in, free the
     cached copy in order to read it in again.	This is
     necessary because we skipped some symbols when we first
     read in the compilation unit (see load_partial_dies).
     This problem could be avoided, but the benefit is unclear.  */
  if (this_cu->cu != NULL)
    free_one_cached_comp_unit (this_cu);

  if (this_cu->is_debug_types)
    init_cutu_and_read_dies (this_cu, NULL, 0, 0, false,
			     build_type_psymtabs_reader, NULL);
  else
    {
      process_psymtab_comp_unit_data info;
      info.want_partial_unit = want_partial_unit;
      info.pretend_language = pretend_language;
      init_cutu_and_read_dies (this_cu, NULL, 0, 0, false,
			       process_psymtab_comp_unit_reader, &info);
    }

  /* Age out any secondary CUs.  */
  age_cached_comp_units (this_cu->dwarf2_per_objfile);
}

/* Reader function for build_type_psymtabs.  */

static void
build_type_psymtabs_reader (const struct die_reader_specs *reader,
			    const gdb_byte *info_ptr,
			    struct die_info *type_unit_die,
			    int has_children,
			    void *data)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = reader->cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct dwarf2_cu *cu = reader->cu;
  struct dwarf2_per_cu_data *per_cu = cu->per_cu;
  struct signatured_type *sig_type;
  struct type_unit_group *tu_group;
  struct attribute *attr;
  struct partial_die_info *first_die;
  CORE_ADDR lowpc, highpc;
  struct partial_symtab *pst;

  gdb_assert (data == NULL);
  gdb_assert (per_cu->is_debug_types);
  sig_type = (struct signatured_type *) per_cu;

  if (! has_children)
    return;

  attr = dwarf2_attr_no_follow (type_unit_die, DW_AT_stmt_list);
  tu_group = get_type_unit_group (cu, attr);

  if (tu_group->tus == nullptr)
    tu_group->tus = new std::vector<signatured_type *>;
  tu_group->tus->push_back (sig_type);

  prepare_one_comp_unit (cu, type_unit_die, language_minimal);
  pst = create_partial_symtab (per_cu, "");
  pst->anonymous = 1;

  first_die = load_partial_dies (reader, info_ptr, 1);

  lowpc = (CORE_ADDR) -1;
  highpc = (CORE_ADDR) 0;
  scan_partial_symbols (first_die, &lowpc, &highpc, 0, cu);

  end_psymtab_common (objfile, pst);
}

/* Struct used to sort TUs by their abbreviation table offset.  */

struct tu_abbrev_offset
{
  tu_abbrev_offset (signatured_type *sig_type_, sect_offset abbrev_offset_)
  : sig_type (sig_type_), abbrev_offset (abbrev_offset_)
  {}

  signatured_type *sig_type;
  sect_offset abbrev_offset;
};

/* Helper routine for build_type_psymtabs_1, passed to std::sort.  */

static bool
sort_tu_by_abbrev_offset (const struct tu_abbrev_offset &a,
			  const struct tu_abbrev_offset &b)
{
  return a.abbrev_offset < b.abbrev_offset;
}

/* Efficiently read all the type units.
   This does the bulk of the work for build_type_psymtabs.

   The efficiency is because we sort TUs by the abbrev table they use and
   only read each abbrev table once.  In one program there are 200K TUs
   sharing 8K abbrev tables.

   The main purpose of this function is to support building the
   dwarf2_per_objfile->type_unit_groups table.
   TUs typically share the DW_AT_stmt_list of the CU they came from, so we
   can collapse the search space by grouping them by stmt_list.
   The savings can be significant, in the same program from above the 200K TUs
   share 8K stmt_list tables.

   FUNC is expected to call get_type_unit_group, which will create the
   struct type_unit_group if necessary and add it to
   dwarf2_per_objfile->type_unit_groups.  */

static void
build_type_psymtabs_1 (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  struct tu_stats *tu_stats = &dwarf2_per_objfile->tu_stats;
  abbrev_table_up abbrev_table;
  sect_offset abbrev_offset;

  /* It's up to the caller to not call us multiple times.  */
  gdb_assert (dwarf2_per_objfile->type_unit_groups == NULL);

  if (dwarf2_per_objfile->all_type_units.empty ())
    return;

  /* TUs typically share abbrev tables, and there can be way more TUs than
     abbrev tables.  Sort by abbrev table to reduce the number of times we
     read each abbrev table in.
     Alternatives are to punt or to maintain a cache of abbrev tables.
     This is simpler and efficient enough for now.

     Later we group TUs by their DW_AT_stmt_list value (as this defines the
     symtab to use).  Typically TUs with the same abbrev offset have the same
     stmt_list value too so in practice this should work well.

     The basic algorithm here is:

      sort TUs by abbrev table
      for each TU with same abbrev table:
	read abbrev table if first user
	read TU top level DIE
	  [IWBN if DWO skeletons had DW_AT_stmt_list]
	call FUNC  */

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "Building type unit groups ...\n");

  /* Sort in a separate table to maintain the order of all_type_units
     for .gdb_index: TU indices directly index all_type_units.  */
  std::vector<tu_abbrev_offset> sorted_by_abbrev;
  sorted_by_abbrev.reserve (dwarf2_per_objfile->all_type_units.size ());

  for (signatured_type *sig_type : dwarf2_per_objfile->all_type_units)
    sorted_by_abbrev.emplace_back
      (sig_type, read_abbrev_offset (dwarf2_per_objfile,
				     sig_type->per_cu.section,
				     sig_type->per_cu.sect_off));

  std::sort (sorted_by_abbrev.begin (), sorted_by_abbrev.end (),
	     sort_tu_by_abbrev_offset);

  abbrev_offset = (sect_offset) ~(unsigned) 0;

  for (const tu_abbrev_offset &tu : sorted_by_abbrev)
    {
      /* Switch to the next abbrev table if necessary.  */
      if (abbrev_table == NULL
	  || tu.abbrev_offset != abbrev_offset)
	{
	  abbrev_offset = tu.abbrev_offset;
	  abbrev_table =
	    abbrev_table_read_table (dwarf2_per_objfile,
				     &dwarf2_per_objfile->abbrev,
				     abbrev_offset);
	  ++tu_stats->nr_uniq_abbrev_tables;
	}

      init_cutu_and_read_dies (&tu.sig_type->per_cu, abbrev_table.get (),
			       0, 0, false, build_type_psymtabs_reader, NULL);
    }
}

/* Print collected type unit statistics.  */

static void
print_tu_stats (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  struct tu_stats *tu_stats = &dwarf2_per_objfile->tu_stats;

  fprintf_unfiltered (gdb_stdlog, "Type unit statistics:\n");
  fprintf_unfiltered (gdb_stdlog, "  %zu TUs\n",
		      dwarf2_per_objfile->all_type_units.size ());
  fprintf_unfiltered (gdb_stdlog, "  %d uniq abbrev tables\n",
		      tu_stats->nr_uniq_abbrev_tables);
  fprintf_unfiltered (gdb_stdlog, "  %d symtabs from stmt_list entries\n",
		      tu_stats->nr_symtabs);
  fprintf_unfiltered (gdb_stdlog, "  %d symtab sharers\n",
		      tu_stats->nr_symtab_sharers);
  fprintf_unfiltered (gdb_stdlog, "  %d type units without a stmt_list\n",
		      tu_stats->nr_stmt_less_type_units);
  fprintf_unfiltered (gdb_stdlog, "  %d all_type_units reallocs\n",
		      tu_stats->nr_all_type_units_reallocs);
}

/* Traversal function for build_type_psymtabs.  */

static int
build_type_psymtab_dependencies (void **slot, void *info)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = (struct dwarf2_per_objfile *) info;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct type_unit_group *tu_group = (struct type_unit_group *) *slot;
  struct dwarf2_per_cu_data *per_cu = &tu_group->per_cu;
  struct partial_symtab *pst = per_cu->v.psymtab;
  int len = (tu_group->tus == nullptr) ? 0 : tu_group->tus->size ();
  int i;

  gdb_assert (len > 0);
  gdb_assert (IS_TYPE_UNIT_GROUP (per_cu));

  pst->number_of_dependencies = len;
  pst->dependencies = objfile->partial_symtabs->allocate_dependencies (len);
  for (i = 0; i < len; ++i)
    {
      struct signatured_type *iter = tu_group->tus->at (i);
      gdb_assert (iter->per_cu.is_debug_types);
      pst->dependencies[i] = iter->per_cu.v.psymtab;
      iter->type_unit_group = tu_group;
    }

  delete tu_group->tus;
  tu_group->tus = nullptr;

  return 1;
}

/* Subroutine of dwarf2_build_psymtabs_hard to simplify it.
   Build partial symbol tables for the .debug_types comp-units.  */

static void
build_type_psymtabs (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  if (! create_all_type_units (dwarf2_per_objfile))
    return;

  build_type_psymtabs_1 (dwarf2_per_objfile);
}

/* Traversal function for process_skeletonless_type_unit.
   Read a TU in a DWO file and build partial symbols for it.  */

static int
process_skeletonless_type_unit (void **slot, void *info)
{
  struct dwo_unit *dwo_unit = (struct dwo_unit *) *slot;
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = (struct dwarf2_per_objfile *) info;
  struct signatured_type find_entry, *entry;

  /* If this TU doesn't exist in the global table, add it and read it in.  */

  if (dwarf2_per_objfile->signatured_types == NULL)
    {
      dwarf2_per_objfile->signatured_types
	= allocate_signatured_type_table (dwarf2_per_objfile->objfile);
    }

  find_entry.signature = dwo_unit->signature;
  slot = htab_find_slot (dwarf2_per_objfile->signatured_types, &find_entry,
			 INSERT);
  /* If we've already seen this type there's nothing to do.  What's happening
     is we're doing our own version of comdat-folding here.  */
  if (*slot != NULL)
    return 1;

  /* This does the job that create_all_type_units would have done for
     this TU.  */
  entry = add_type_unit (dwarf2_per_objfile, dwo_unit->signature, slot);
  fill_in_sig_entry_from_dwo_entry (dwarf2_per_objfile, entry, dwo_unit);
  *slot = entry;

  /* This does the job that build_type_psymtabs_1 would have done.  */
  init_cutu_and_read_dies (&entry->per_cu, NULL, 0, 0, false,
			   build_type_psymtabs_reader, NULL);

  return 1;
}

/* Traversal function for process_skeletonless_type_units.  */

static int
process_dwo_file_for_skeletonless_type_units (void **slot, void *info)
{
  struct dwo_file *dwo_file = (struct dwo_file *) *slot;

  if (dwo_file->tus != NULL)
    {
      htab_traverse_noresize (dwo_file->tus,
			      process_skeletonless_type_unit, info);
    }

  return 1;
}

/* Scan all TUs of DWO files, verifying we've processed them.
   This is needed in case a TU was emitted without its skeleton.
   Note: This can't be done until we know what all the DWO files are.  */

static void
process_skeletonless_type_units (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  /* Skeletonless TUs in DWP files without .gdb_index is not supported yet.  */
  if (get_dwp_file (dwarf2_per_objfile) == NULL
      && dwarf2_per_objfile->dwo_files != NULL)
    {
      htab_traverse_noresize (dwarf2_per_objfile->dwo_files.get (),
			      process_dwo_file_for_skeletonless_type_units,
			      dwarf2_per_objfile);
    }
}

/* Compute the 'user' field for each psymtab in DWARF2_PER_OBJFILE.  */

static void
set_partial_user (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    {
      struct partial_symtab *pst = per_cu->v.psymtab;

      if (pst == NULL)
	continue;

      for (int j = 0; j < pst->number_of_dependencies; ++j)
	{
	  /* Set the 'user' field only if it is not already set.  */
	  if (pst->dependencies[j]->user == NULL)
	    pst->dependencies[j]->user = pst;
	}
    }
}

/* Build the partial symbol table by doing a quick pass through the
   .debug_info and .debug_abbrev sections.  */

static void
dwarf2_build_psymtabs_hard (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Building psymtabs of objfile %s ...\n",
			  objfile_name (objfile));
    }

  dwarf2_per_objfile->reading_partial_symbols = 1;

  dwarf2_read_section (objfile, &dwarf2_per_objfile->info);

  /* Any cached compilation units will be linked by the per-objfile
     read_in_chain.  Make sure to free them when we're done.  */
  free_cached_comp_units freer (dwarf2_per_objfile);

  build_type_psymtabs (dwarf2_per_objfile);

  create_all_comp_units (dwarf2_per_objfile);

  /* Create a temporary address map on a temporary obstack.  We later
     copy this to the final obstack.  */
  auto_obstack temp_obstack;

  scoped_restore save_psymtabs_addrmap
    = make_scoped_restore (&objfile->partial_symtabs->psymtabs_addrmap,
			   addrmap_create_mutable (&temp_obstack));

  for (dwarf2_per_cu_data *per_cu : dwarf2_per_objfile->all_comp_units)
    process_psymtab_comp_unit (per_cu, 0, language_minimal);

  /* This has to wait until we read the CUs, we need the list of DWOs.  */
  process_skeletonless_type_units (dwarf2_per_objfile);

  /* Now that all TUs have been processed we can fill in the dependencies.  */
  if (dwarf2_per_objfile->type_unit_groups != NULL)
    {
      htab_traverse_noresize (dwarf2_per_objfile->type_unit_groups,
			      build_type_psymtab_dependencies, dwarf2_per_objfile);
    }

  if (dwarf_read_debug)
    print_tu_stats (dwarf2_per_objfile);

  set_partial_user (dwarf2_per_objfile);

  objfile->partial_symtabs->psymtabs_addrmap
    = addrmap_create_fixed (objfile->partial_symtabs->psymtabs_addrmap,
			    objfile->partial_symtabs->obstack ());
  /* At this point we want to keep the address map.  */
  save_psymtabs_addrmap.release ();

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "Done building psymtabs of %s\n",
			objfile_name (objfile));
}

/* die_reader_func for load_partial_comp_unit.  */

static void
load_partial_comp_unit_reader (const struct die_reader_specs *reader,
			       const gdb_byte *info_ptr,
			       struct die_info *comp_unit_die,
			       int has_children,
			       void *data)
{
  struct dwarf2_cu *cu = reader->cu;

  prepare_one_comp_unit (cu, comp_unit_die, language_minimal);

  /* Check if comp unit has_children.
     If so, read the rest of the partial symbols from this comp unit.
     If not, there's no more debug_info for this comp unit.  */
  if (has_children)
    load_partial_dies (reader, info_ptr, 0);
}

/* Load the partial DIEs for a secondary CU into memory.
   This is also used when rereading a primary CU with load_all_dies.  */

static void
load_partial_comp_unit (struct dwarf2_per_cu_data *this_cu)
{
  init_cutu_and_read_dies (this_cu, NULL, 1, 1, false,
			   load_partial_comp_unit_reader, NULL);
}

static void
read_comp_units_from_section (struct dwarf2_per_objfile *dwarf2_per_objfile,
			      struct dwarf2_section_info *section,
			      struct dwarf2_section_info *abbrev_section,
			      unsigned int is_dwz)
{
  const gdb_byte *info_ptr;
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "Reading %s for %s\n",
			get_section_name (section),
			get_section_file_name (section));

  dwarf2_read_section (objfile, section);

  info_ptr = section->buffer;

  while (info_ptr < section->buffer + section->size)
    {
      struct dwarf2_per_cu_data *this_cu;

      sect_offset sect_off = (sect_offset) (info_ptr - section->buffer);

      comp_unit_head cu_header;
      read_and_check_comp_unit_head (dwarf2_per_objfile, &cu_header, section,
				     abbrev_section, info_ptr,
				     rcuh_kind::COMPILE);

      /* Save the compilation unit for later lookup.  */
      if (cu_header.unit_type != DW_UT_type)
	{
	  this_cu = XOBNEW (&objfile->objfile_obstack,
			    struct dwarf2_per_cu_data);
	  memset (this_cu, 0, sizeof (*this_cu));
	}
      else
	{
	  auto sig_type = XOBNEW (&objfile->objfile_obstack,
				  struct signatured_type);
	  memset (sig_type, 0, sizeof (*sig_type));
	  sig_type->signature = cu_header.signature;
	  sig_type->type_offset_in_tu = cu_header.type_cu_offset_in_tu;
	  this_cu = &sig_type->per_cu;
	}
      this_cu->is_debug_types = (cu_header.unit_type == DW_UT_type);
      this_cu->sect_off = sect_off;
      this_cu->length = cu_header.length + cu_header.initial_length_size;
      this_cu->is_dwz = is_dwz;
      this_cu->dwarf2_per_objfile = dwarf2_per_objfile;
      this_cu->section = section;

      dwarf2_per_objfile->all_comp_units.push_back (this_cu);

      info_ptr = info_ptr + this_cu->length;
    }
}

/* Create a list of all compilation units in OBJFILE.
   This is only done for -readnow and building partial symtabs.  */

static void
create_all_comp_units (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  gdb_assert (dwarf2_per_objfile->all_comp_units.empty ());
  read_comp_units_from_section (dwarf2_per_objfile, &dwarf2_per_objfile->info,
				&dwarf2_per_objfile->abbrev, 0);

  dwz_file *dwz = dwarf2_get_dwz_file (dwarf2_per_objfile);
  if (dwz != NULL)
    read_comp_units_from_section (dwarf2_per_objfile, &dwz->info, &dwz->abbrev,
				  1);
}

/* Process all loaded DIEs for compilation unit CU, starting at
   FIRST_DIE.  The caller should pass SET_ADDRMAP == 1 if the compilation
   unit DIE did not have PC info (DW_AT_low_pc and DW_AT_high_pc, or
   DW_AT_ranges).  See the comments of add_partial_subprogram on how
   SET_ADDRMAP is used and how *LOWPC and *HIGHPC are updated.  */

static void
scan_partial_symbols (struct partial_die_info *first_die, CORE_ADDR *lowpc,
		      CORE_ADDR *highpc, int set_addrmap,
		      struct dwarf2_cu *cu)
{
  struct partial_die_info *pdi;

  /* Now, march along the PDI's, descending into ones which have
     interesting children but skipping the children of the other ones,
     until we reach the end of the compilation unit.  */

  pdi = first_die;

  while (pdi != NULL)
    {
      pdi->fixup (cu);

      /* Anonymous namespaces or modules have no name but have interesting
	 children, so we need to look at them.  Ditto for anonymous
	 enums.  */

      if (pdi->name != NULL || pdi->tag == DW_TAG_namespace
	  || pdi->tag == DW_TAG_module || pdi->tag == DW_TAG_enumeration_type
	  || pdi->tag == DW_TAG_imported_unit
	  || pdi->tag == DW_TAG_inlined_subroutine)
	{
	  switch (pdi->tag)
	    {
	    case DW_TAG_subprogram:
	    case DW_TAG_inlined_subroutine:
	      add_partial_subprogram (pdi, lowpc, highpc, set_addrmap, cu);
	      break;
	    case DW_TAG_constant:
	    case DW_TAG_variable:
	    case DW_TAG_typedef:
	    case DW_TAG_union_type:
	      if (!pdi->is_declaration)
		{
		  add_partial_symbol (pdi, cu);
		}
	      break;
	    case DW_TAG_class_type:
	    case DW_TAG_interface_type:
	    case DW_TAG_structure_type:
	      if (!pdi->is_declaration)
		{
		  add_partial_symbol (pdi, cu);
		}
	      if ((cu->language == language_rust
		   || cu->language == language_cplus) && pdi->has_children)
		scan_partial_symbols (pdi->die_child, lowpc, highpc,
				      set_addrmap, cu);
	      break;
	    case DW_TAG_enumeration_type:
	      if (!pdi->is_declaration)
		add_partial_enumeration (pdi, cu);
	      break;
	    case DW_TAG_base_type:
            case DW_TAG_subrange_type:
	      /* File scope base type definitions are added to the partial
	         symbol table.  */
	      add_partial_symbol (pdi, cu);
	      break;
	    case DW_TAG_namespace:
	      add_partial_namespace (pdi, lowpc, highpc, set_addrmap, cu);
	      break;
	    case DW_TAG_module:
	      if (!pdi->is_declaration)
		add_partial_module (pdi, lowpc, highpc, set_addrmap, cu);
	      break;
	    case DW_TAG_imported_unit:
	      {
		struct dwarf2_per_cu_data *per_cu;

		/* For now we don't handle imported units in type units.  */
		if (cu->per_cu->is_debug_types)
		  {
		    error (_("Dwarf Error: DW_TAG_imported_unit is not"
			     " supported in type units [in module %s]"),
			   objfile_name (cu->per_cu->dwarf2_per_objfile->objfile));
		  }

		per_cu = dwarf2_find_containing_comp_unit
			   (pdi->d.sect_off, pdi->is_dwz,
			    cu->per_cu->dwarf2_per_objfile);

		/* Go read the partial unit, if needed.  */
		if (per_cu->v.psymtab == NULL)
		  process_psymtab_comp_unit (per_cu, 1, cu->language);

		cu->per_cu->imported_symtabs_push (per_cu);
	      }
	      break;
	    case DW_TAG_imported_declaration:
	      add_partial_symbol (pdi, cu);
	      break;
	    default:
	      break;
	    }
	}

      /* If the die has a sibling, skip to the sibling.  */

      pdi = pdi->die_sibling;
    }
}

/* Functions used to compute the fully scoped name of a partial DIE.

   Normally, this is simple.  For C++, the parent DIE's fully scoped
   name is concatenated with "::" and the partial DIE's name.
   Enumerators are an exception; they use the scope of their parent
   enumeration type, i.e. the name of the enumeration type is not
   prepended to the enumerator.

   There are two complexities.  One is DW_AT_specification; in this
   case "parent" means the parent of the target of the specification,
   instead of the direct parent of the DIE.  The other is compilers
   which do not emit DW_TAG_namespace; in this case we try to guess
   the fully qualified name of structure types from their members'
   linkage names.  This must be done using the DIE's children rather
   than the children of any DW_AT_specification target.  We only need
   to do this for structures at the top level, i.e. if the target of
   any DW_AT_specification (if any; otherwise the DIE itself) does not
   have a parent.  */

/* Compute the scope prefix associated with PDI's parent, in
   compilation unit CU.  The result will be allocated on CU's
   comp_unit_obstack, or a copy of the already allocated PDI->NAME
   field.  NULL is returned if no prefix is necessary.  */
static const char *
partial_die_parent_scope (struct partial_die_info *pdi,
			  struct dwarf2_cu *cu)
{
  const char *grandparent_scope;
  struct partial_die_info *parent, *real_pdi;

  /* We need to look at our parent DIE; if we have a DW_AT_specification,
     then this means the parent of the specification DIE.  */

  real_pdi = pdi;
  while (real_pdi->has_specification)
    {
      auto res = find_partial_die (real_pdi->spec_offset,
				   real_pdi->spec_is_dwz, cu);
      real_pdi = res.pdi;
      cu = res.cu;
    }

  parent = real_pdi->die_parent;
  if (parent == NULL)
    return NULL;

  if (parent->scope_set)
    return parent->scope;

  parent->fixup (cu);

  grandparent_scope = partial_die_parent_scope (parent, cu);

  /* GCC 4.0 and 4.1 had a bug (PR c++/28460) where they generated bogus
     DW_TAG_namespace DIEs with a name of "::" for the global namespace.
     Work around this problem here.  */
  if (cu->language == language_cplus
      && parent->tag == DW_TAG_namespace
      && strcmp (parent->name, "::") == 0
      && grandparent_scope == NULL)
    {
      parent->scope = NULL;
      parent->scope_set = 1;
      return NULL;
    }

  /* Nested subroutines in Fortran get a prefix.  */
  if (pdi->tag == DW_TAG_enumerator)
    /* Enumerators should not get the name of the enumeration as a prefix.  */
    parent->scope = grandparent_scope;
  else if (parent->tag == DW_TAG_namespace
      || parent->tag == DW_TAG_module
      || parent->tag == DW_TAG_structure_type
      || parent->tag == DW_TAG_class_type
      || parent->tag == DW_TAG_interface_type
      || parent->tag == DW_TAG_union_type
      || parent->tag == DW_TAG_enumeration_type
      || (cu->language == language_fortran
	  && parent->tag == DW_TAG_subprogram
	  && pdi->tag == DW_TAG_subprogram))
    {
      if (grandparent_scope == NULL)
	parent->scope = parent->name;
      else
	parent->scope = typename_concat (&cu->comp_unit_obstack,
					 grandparent_scope,
					 parent->name, 0, cu);
    }
  else
    {
      /* FIXME drow/2004-04-01: What should we be doing with
	 function-local names?  For partial symbols, we should probably be
	 ignoring them.  */
      complaint (_("unhandled containing DIE tag %s for DIE at %s"),
		 dwarf_tag_name (parent->tag),
		 sect_offset_str (pdi->sect_off));
      parent->scope = grandparent_scope;
    }

  parent->scope_set = 1;
  return parent->scope;
}

/* Return the fully scoped name associated with PDI, from compilation unit
   CU.  The result will be allocated with malloc.  */

static char *
partial_die_full_name (struct partial_die_info *pdi,
		       struct dwarf2_cu *cu)
{
  const char *parent_scope;

  /* If this is a template instantiation, we can not work out the
     template arguments from partial DIEs.  So, unfortunately, we have
     to go through the full DIEs.  At least any work we do building
     types here will be reused if full symbols are loaded later.  */
  if (pdi->has_template_arguments)
    {
      pdi->fixup (cu);

      if (pdi->name != NULL && strchr (pdi->name, '<') == NULL)
	{
	  struct die_info *die;
	  struct attribute attr;
	  struct dwarf2_cu *ref_cu = cu;

	  /* DW_FORM_ref_addr is using section offset.  */
	  attr.name = (enum dwarf_attribute) 0;
	  attr.form = DW_FORM_ref_addr;
	  attr.u.unsnd = to_underlying (pdi->sect_off);
	  die = follow_die_ref (NULL, &attr, &ref_cu);

	  return xstrdup (dwarf2_full_name (NULL, die, ref_cu));
	}
    }

  parent_scope = partial_die_parent_scope (pdi, cu);
  if (parent_scope == NULL)
    return NULL;
  else
    return typename_concat (NULL, parent_scope, pdi->name, 0, cu);
}

static void
add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  CORE_ADDR addr = 0;
  const char *actual_name = NULL;
  CORE_ADDR baseaddr;
  char *built_actual_name;

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  built_actual_name = partial_die_full_name (pdi, cu);
  if (built_actual_name != NULL)
    actual_name = built_actual_name;

  if (actual_name == NULL)
    actual_name = pdi->name;

  switch (pdi->tag)
    {
    case DW_TAG_inlined_subroutine:
    case DW_TAG_subprogram:
      addr = (gdbarch_adjust_dwarf2_addr (gdbarch, pdi->lowpc + baseaddr)
	      - baseaddr);
      if (pdi->is_external
	  || cu->language == language_ada
	  || (cu->language == language_fortran
	      && pdi->die_parent != NULL
	      && pdi->die_parent->tag == DW_TAG_subprogram))
	{
          /* Normally, only "external" DIEs are part of the global scope.
             But in Ada and Fortran, we want to be able to access nested
             procedures globally.  So all Ada and Fortran subprograms are
             stored in the global scope.  */
	  add_psymbol_to_list (actual_name,
			       built_actual_name != NULL,
			       VAR_DOMAIN, LOC_BLOCK,
			       SECT_OFF_TEXT (objfile),
			       psymbol_placement::GLOBAL,
			       addr,
			       cu->language, objfile);
	}
      else
	{
	  add_psymbol_to_list (actual_name,
			       built_actual_name != NULL,
			       VAR_DOMAIN, LOC_BLOCK,
			       SECT_OFF_TEXT (objfile),
			       psymbol_placement::STATIC,
			       addr, cu->language, objfile);
	}

      if (pdi->main_subprogram && actual_name != NULL)
	set_objfile_main_name (objfile, actual_name, cu->language);
      break;
    case DW_TAG_constant:
      add_psymbol_to_list (actual_name,
			   built_actual_name != NULL, VAR_DOMAIN, LOC_STATIC,
			   -1, (pdi->is_external
				? psymbol_placement::GLOBAL
				: psymbol_placement::STATIC),
			   0, cu->language, objfile);
      break;
    case DW_TAG_variable:
      if (pdi->d.locdesc)
	addr = decode_locdesc (pdi->d.locdesc, cu);

      if (pdi->d.locdesc
	  && addr == 0
	  && !dwarf2_per_objfile->has_section_at_zero)
	{
	  /* A global or static variable may also have been stripped
	     out by the linker if unused, in which case its address
	     will be nullified; do not add such variables into partial
	     symbol table then.  */
	}
      else if (pdi->is_external)
	{
	  /* Global Variable.
	     Don't enter into the minimal symbol tables as there is
	     a minimal symbol table entry from the ELF symbols already.
	     Enter into partial symbol table if it has a location
	     descriptor or a type.
	     If the location descriptor is missing, new_symbol will create
	     a LOC_UNRESOLVED symbol, the address of the variable will then
	     be determined from the minimal symbol table whenever the variable
	     is referenced.
	     The address for the partial symbol table entry is not
	     used by GDB, but it comes in handy for debugging partial symbol
	     table building.  */

	  if (pdi->d.locdesc || pdi->has_type)
	    add_psymbol_to_list (actual_name,
				 built_actual_name != NULL,
				 VAR_DOMAIN, LOC_STATIC,
				 SECT_OFF_TEXT (objfile),
				 psymbol_placement::GLOBAL,
				 addr, cu->language, objfile);
	}
      else
	{
	  int has_loc = pdi->d.locdesc != NULL;

	  /* Static Variable.  Skip symbols whose value we cannot know (those
	     without location descriptors or constant values).  */
	  if (!has_loc && !pdi->has_const_value)
	    {
	      xfree (built_actual_name);
	      return;
	    }

	  add_psymbol_to_list (actual_name,
			       built_actual_name != NULL,
			       VAR_DOMAIN, LOC_STATIC,
			       SECT_OFF_TEXT (objfile),
			       psymbol_placement::STATIC,
			       has_loc ? addr : 0,
			       cu->language, objfile);
	}
      break;
    case DW_TAG_typedef:
    case DW_TAG_base_type:
    case DW_TAG_subrange_type:
      add_psymbol_to_list (actual_name,
			   built_actual_name != NULL,
			   VAR_DOMAIN, LOC_TYPEDEF, -1,
			   psymbol_placement::STATIC,
			   0, cu->language, objfile);
      break;
    case DW_TAG_imported_declaration:
    case DW_TAG_namespace:
      add_psymbol_to_list (actual_name,
			   built_actual_name != NULL,
			   VAR_DOMAIN, LOC_TYPEDEF, -1,
			   psymbol_placement::GLOBAL,
			   0, cu->language, objfile);
      break;
    case DW_TAG_module:
      /* With Fortran 77 there might be a "BLOCK DATA" module
         available without any name.  If so, we skip the module as it
         doesn't bring any value.  */
      if (actual_name != nullptr)
	add_psymbol_to_list (actual_name,
			     built_actual_name != NULL,
			     MODULE_DOMAIN, LOC_TYPEDEF, -1,
			     psymbol_placement::GLOBAL,
			     0, cu->language, objfile);
      break;
    case DW_TAG_class_type:
    case DW_TAG_interface_type:
    case DW_TAG_structure_type:
    case DW_TAG_union_type:
    case DW_TAG_enumeration_type:
      /* Skip external references.  The DWARF standard says in the section
         about "Structure, Union, and Class Type Entries": "An incomplete
         structure, union or class type is represented by a structure,
         union or class entry that does not have a byte size attribute
         and that has a DW_AT_declaration attribute."  */
      if (!pdi->has_byte_size && pdi->is_declaration)
	{
	  xfree (built_actual_name);
	  return;
	}

      /* NOTE: carlton/2003-10-07: See comment in new_symbol about
	 static vs. global.  */
      add_psymbol_to_list (actual_name,
			   built_actual_name != NULL,
			   STRUCT_DOMAIN, LOC_TYPEDEF, -1,
			   cu->language == language_cplus
			   ? psymbol_placement::GLOBAL
			   : psymbol_placement::STATIC,
			   0, cu->language, objfile);

      break;
    case DW_TAG_enumerator:
      add_psymbol_to_list (actual_name,
			   built_actual_name != NULL,
			   VAR_DOMAIN, LOC_CONST, -1,
			   cu->language == language_cplus
			   ? psymbol_placement::GLOBAL
			   : psymbol_placement::STATIC,
			   0, cu->language, objfile);
      break;
    default:
      break;
    }

  xfree (built_actual_name);
}

/* Read a partial die corresponding to a namespace; also, add a symbol
   corresponding to that namespace to the symbol table.  NAMESPACE is
   the name of the enclosing namespace.  */

static void
add_partial_namespace (struct partial_die_info *pdi,
		       CORE_ADDR *lowpc, CORE_ADDR *highpc,
		       int set_addrmap, struct dwarf2_cu *cu)
{
  /* Add a symbol for the namespace.  */

  add_partial_symbol (pdi, cu);

  /* Now scan partial symbols in that namespace.  */

  if (pdi->has_children)
    scan_partial_symbols (pdi->die_child, lowpc, highpc, set_addrmap, cu);
}

/* Read a partial die corresponding to a Fortran module.  */

static void
add_partial_module (struct partial_die_info *pdi, CORE_ADDR *lowpc,
		    CORE_ADDR *highpc, int set_addrmap, struct dwarf2_cu *cu)
{
  /* Add a symbol for the namespace.  */

  add_partial_symbol (pdi, cu);

  /* Now scan partial symbols in that module.  */

  if (pdi->has_children)
    scan_partial_symbols (pdi->die_child, lowpc, highpc, set_addrmap, cu);
}

/* Read a partial die corresponding to a subprogram or an inlined
   subprogram and create a partial symbol for that subprogram.
   When the CU language allows it, this routine also defines a partial
   symbol for each nested subprogram that this subprogram contains.
   If SET_ADDRMAP is true, record the covered ranges in the addrmap.
   Set *LOWPC and *HIGHPC to the lowest and highest PC values found in PDI.

   PDI may also be a lexical block, in which case we simply search
   recursively for subprograms defined inside that lexical block.
   Again, this is only performed when the CU language allows this
   type of definitions.  */

static void
add_partial_subprogram (struct partial_die_info *pdi,
			CORE_ADDR *lowpc, CORE_ADDR *highpc,
			int set_addrmap, struct dwarf2_cu *cu)
{
  if (pdi->tag == DW_TAG_subprogram || pdi->tag == DW_TAG_inlined_subroutine)
    {
      if (pdi->has_pc_info)
        {
          if (pdi->lowpc < *lowpc)
            *lowpc = pdi->lowpc;
          if (pdi->highpc > *highpc)
            *highpc = pdi->highpc;
	  if (set_addrmap)
	    {
	      struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
	      struct gdbarch *gdbarch = get_objfile_arch (objfile);
	      CORE_ADDR baseaddr;
	      CORE_ADDR this_highpc;
	      CORE_ADDR this_lowpc;

	      baseaddr = ANOFFSET (objfile->section_offsets,
				   SECT_OFF_TEXT (objfile));
	      this_lowpc
		= (gdbarch_adjust_dwarf2_addr (gdbarch,
					       pdi->lowpc + baseaddr)
		   - baseaddr);
	      this_highpc
		= (gdbarch_adjust_dwarf2_addr (gdbarch,
					       pdi->highpc + baseaddr)
		   - baseaddr);
	      addrmap_set_empty (objfile->partial_symtabs->psymtabs_addrmap,
				 this_lowpc, this_highpc - 1,
				 cu->per_cu->v.psymtab);
	    }
        }

      if (pdi->has_pc_info || (!pdi->is_external && pdi->may_be_inlined))
	{
          if (!pdi->is_declaration)
	    /* Ignore subprogram DIEs that do not have a name, they are
	       illegal.  Do not emit a complaint at this point, we will
	       do so when we convert this psymtab into a symtab.  */
	    if (pdi->name)
	      add_partial_symbol (pdi, cu);
        }
    }

  if (! pdi->has_children)
    return;

  if (cu->language == language_ada || cu->language == language_fortran)
    {
      pdi = pdi->die_child;
      while (pdi != NULL)
	{
	  pdi->fixup (cu);
	  if (pdi->tag == DW_TAG_subprogram
	      || pdi->tag == DW_TAG_inlined_subroutine
	      || pdi->tag == DW_TAG_lexical_block)
	    add_partial_subprogram (pdi, lowpc, highpc, set_addrmap, cu);
	  pdi = pdi->die_sibling;
	}
    }
}

/* Read a partial die corresponding to an enumeration type.  */

static void
add_partial_enumeration (struct partial_die_info *enum_pdi,
			 struct dwarf2_cu *cu)
{
  struct partial_die_info *pdi;

  if (enum_pdi->name != NULL)
    add_partial_symbol (enum_pdi, cu);

  pdi = enum_pdi->die_child;
  while (pdi)
    {
      if (pdi->tag != DW_TAG_enumerator || pdi->name == NULL)
	complaint (_("malformed enumerator DIE ignored"));
      else
	add_partial_symbol (pdi, cu);
      pdi = pdi->die_sibling;
    }
}

/* Return the initial uleb128 in the die at INFO_PTR.  */

static unsigned int
peek_abbrev_code (bfd *abfd, const gdb_byte *info_ptr)
{
  unsigned int bytes_read;

  return read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
}

/* Read the initial uleb128 in the die at INFO_PTR in compilation unit
   READER::CU.  Use READER::ABBREV_TABLE to lookup any abbreviation.

   Return the corresponding abbrev, or NULL if the number is zero (indicating
   an empty DIE).  In either case *BYTES_READ will be set to the length of
   the initial number.  */

static struct abbrev_info *
peek_die_abbrev (const die_reader_specs &reader,
		 const gdb_byte *info_ptr, unsigned int *bytes_read)
{
  dwarf2_cu *cu = reader.cu;
  bfd *abfd = cu->per_cu->dwarf2_per_objfile->objfile->obfd;
  unsigned int abbrev_number
    = read_unsigned_leb128 (abfd, info_ptr, bytes_read);

  if (abbrev_number == 0)
    return NULL;

  abbrev_info *abbrev = reader.abbrev_table->lookup_abbrev (abbrev_number);
  if (!abbrev)
    {
      error (_("Dwarf Error: Could not find abbrev number %d in %s"
	       " at offset %s [in module %s]"),
	     abbrev_number, cu->per_cu->is_debug_types ? "TU" : "CU",
	     sect_offset_str (cu->header.sect_off), bfd_get_filename (abfd));
    }

  return abbrev;
}

/* Scan the debug information for CU starting at INFO_PTR in buffer BUFFER.
   Returns a pointer to the end of a series of DIEs, terminated by an empty
   DIE.  Any children of the skipped DIEs will also be skipped.  */

static const gdb_byte *
skip_children (const struct die_reader_specs *reader, const gdb_byte *info_ptr)
{
  while (1)
    {
      unsigned int bytes_read;
      abbrev_info *abbrev = peek_die_abbrev (*reader, info_ptr, &bytes_read);

      if (abbrev == NULL)
	return info_ptr + bytes_read;
      else
	info_ptr = skip_one_die (reader, info_ptr + bytes_read, abbrev);
    }
}

/* Scan the debug information for CU starting at INFO_PTR in buffer BUFFER.
   INFO_PTR should point just after the initial uleb128 of a DIE, and the
   abbrev corresponding to that skipped uleb128 should be passed in
   ABBREV.  Returns a pointer to this DIE's sibling, skipping any
   children.  */

static const gdb_byte *
skip_one_die (const struct die_reader_specs *reader, const gdb_byte *info_ptr,
	      struct abbrev_info *abbrev)
{
  unsigned int bytes_read;
  struct attribute attr;
  bfd *abfd = reader->abfd;
  struct dwarf2_cu *cu = reader->cu;
  const gdb_byte *buffer = reader->buffer;
  const gdb_byte *buffer_end = reader->buffer_end;
  unsigned int form, i;

  for (i = 0; i < abbrev->num_attrs; i++)
    {
      /* The only abbrev we care about is DW_AT_sibling.  */
      if (abbrev->attrs[i].name == DW_AT_sibling)
	{
	  bool ignored;
	  read_attribute (reader, &attr, &abbrev->attrs[i], info_ptr,
			  &ignored);
	  if (attr.form == DW_FORM_ref_addr)
	    complaint (_("ignoring absolute DW_AT_sibling"));
	  else
	    {
	      sect_offset off = dwarf2_get_ref_die_offset (&attr);
	      const gdb_byte *sibling_ptr = buffer + to_underlying (off);

	      if (sibling_ptr < info_ptr)
		complaint (_("DW_AT_sibling points backwards"));
	      else if (sibling_ptr > reader->buffer_end)
		dwarf2_section_buffer_overflow_complaint (reader->die_section);
	      else
		return sibling_ptr;
	    }
	}

      /* If it isn't DW_AT_sibling, skip this attribute.  */
      form = abbrev->attrs[i].form;
    skip_attribute:
      switch (form)
	{
	case DW_FORM_ref_addr:
	  /* In DWARF 2, DW_FORM_ref_addr is address sized; in DWARF 3
	     and later it is offset sized.  */
	  if (cu->header.version == 2)
	    info_ptr += cu->header.addr_size;
	  else
	    info_ptr += cu->header.offset_size;
	  break;
	case DW_FORM_GNU_ref_alt:
	  info_ptr += cu->header.offset_size;
	  break;
	case DW_FORM_addr:
	  info_ptr += cu->header.addr_size;
	  break;
	case DW_FORM_data1:
	case DW_FORM_ref1:
	case DW_FORM_flag:
	case DW_FORM_strx1:
	  info_ptr += 1;
	  break;
	case DW_FORM_flag_present:
	case DW_FORM_implicit_const:
	  break;
	case DW_FORM_data2:
	case DW_FORM_ref2:
	case DW_FORM_strx2:
	  info_ptr += 2;
	  break;
	case DW_FORM_strx3:
	  info_ptr += 3;
	  break;
	case DW_FORM_data4:
	case DW_FORM_ref4:
	case DW_FORM_strx4:
	  info_ptr += 4;
	  break;
	case DW_FORM_data8:
	case DW_FORM_ref8:
	case DW_FORM_ref_sig8:
	  info_ptr += 8;
	  break;
	case DW_FORM_data16:
	  info_ptr += 16;
	  break;
	case DW_FORM_string:
	  read_direct_string (abfd, info_ptr, &bytes_read);
	  info_ptr += bytes_read;
	  break;
	case DW_FORM_sec_offset:
	case DW_FORM_strp:
	case DW_FORM_GNU_strp_alt:
	  info_ptr += cu->header.offset_size;
	  break;
	case DW_FORM_exprloc:
	case DW_FORM_block:
	  info_ptr += read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
	  info_ptr += bytes_read;
	  break;
	case DW_FORM_block1:
	  info_ptr += 1 + read_1_byte (abfd, info_ptr);
	  break;
	case DW_FORM_block2:
	  info_ptr += 2 + read_2_bytes (abfd, info_ptr);
	  break;
	case DW_FORM_block4:
	  info_ptr += 4 + read_4_bytes (abfd, info_ptr);
	  break;
	case DW_FORM_addrx:
	case DW_FORM_strx:
	case DW_FORM_sdata:
	case DW_FORM_udata:
	case DW_FORM_ref_udata:
	case DW_FORM_GNU_addr_index:
	case DW_FORM_GNU_str_index:
	case DW_FORM_loclistx:
	case DW_FORM_rnglistx:
	  info_ptr = safe_skip_leb128 (info_ptr, buffer_end);
	  break;
	case DW_FORM_indirect:
	  form = read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
	  info_ptr += bytes_read;
	  /* We need to continue parsing from here, so just go back to
	     the top.  */
	  goto skip_attribute;

	default:
	  error (_("Dwarf Error: Cannot handle %s "
		   "in DWARF reader [in module %s]"),
		 dwarf_form_name (form),
		 bfd_get_filename (abfd));
	}
    }

  if (abbrev->has_children)
    return skip_children (reader, info_ptr);
  else
    return info_ptr;
}

/* Locate ORIG_PDI's sibling.
   INFO_PTR should point to the start of the next DIE after ORIG_PDI.  */

static const gdb_byte *
locate_pdi_sibling (const struct die_reader_specs *reader,
		    struct partial_die_info *orig_pdi,
		    const gdb_byte *info_ptr)
{
  /* Do we know the sibling already?  */

  if (orig_pdi->sibling)
    return orig_pdi->sibling;

  /* Are there any children to deal with?  */

  if (!orig_pdi->has_children)
    return info_ptr;

  /* Skip the children the long way.  */

  return skip_children (reader, info_ptr);
}

/* Expand this partial symbol table into a full symbol table.  SELF is
   not NULL.  */

static void
dwarf2_read_symtab (struct partial_symtab *self,
		    struct objfile *objfile)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = get_dwarf2_per_objfile (objfile);

  if (self->readin)
    {
      warning (_("bug: psymtab for %s is already read in."),
	       self->filename);
    }
  else
    {
      if (info_verbose)
	{
	  printf_filtered (_("Reading in symbols for %s..."),
			   self->filename);
	  gdb_flush (gdb_stdout);
	}

      /* If this psymtab is constructed from a debug-only objfile, the
	 has_section_at_zero flag will not necessarily be correct.  We
	 can get the correct value for this flag by looking at the data
	 associated with the (presumably stripped) associated objfile.  */
      if (objfile->separate_debug_objfile_backlink)
	{
	  struct dwarf2_per_objfile *dpo_backlink
	    = get_dwarf2_per_objfile (objfile->separate_debug_objfile_backlink);

	  dwarf2_per_objfile->has_section_at_zero
	    = dpo_backlink->has_section_at_zero;
	}

      dwarf2_per_objfile->reading_partial_symbols = 0;

      psymtab_to_symtab_1 (self);

      /* Finish up the debug error message.  */
      if (info_verbose)
	printf_filtered (_("done.\n"));
    }

  process_cu_includes (dwarf2_per_objfile);
}

/* Reading in full CUs.  */

/* Add PER_CU to the queue.  */

static void
queue_comp_unit (struct dwarf2_per_cu_data *per_cu,
		 enum language pretend_language)
{
  struct dwarf2_queue_item *item;

  per_cu->queued = 1;
  item = XNEW (struct dwarf2_queue_item);
  item->per_cu = per_cu;
  item->pretend_language = pretend_language;
  item->next = NULL;

  if (dwarf2_queue == NULL)
    dwarf2_queue = item;
  else
    dwarf2_queue_tail->next = item;

  dwarf2_queue_tail = item;
}

/* If PER_CU is not yet queued, add it to the queue.
   If DEPENDENT_CU is non-NULL, it has a reference to PER_CU so add a
   dependency.
   The result is non-zero if PER_CU was queued, otherwise the result is zero
   meaning either PER_CU is already queued or it is already loaded.

   N.B. There is an invariant here that if a CU is queued then it is loaded.
   The caller is required to load PER_CU if we return non-zero.  */

static int
maybe_queue_comp_unit (struct dwarf2_cu *dependent_cu,
		       struct dwarf2_per_cu_data *per_cu,
		       enum language pretend_language)
{
  /* We may arrive here during partial symbol reading, if we need full
     DIEs to process an unusual case (e.g. template arguments).  Do
     not queue PER_CU, just tell our caller to load its DIEs.  */
  if (per_cu->dwarf2_per_objfile->reading_partial_symbols)
    {
      if (per_cu->cu == NULL || per_cu->cu->dies == NULL)
	return 1;
      return 0;
    }

  /* Mark the dependence relation so that we don't flush PER_CU
     too early.  */
  if (dependent_cu != NULL)
    dwarf2_add_dependence (dependent_cu, per_cu);

  /* If it's already on the queue, we have nothing to do.  */
  if (per_cu->queued)
    return 0;

  /* If the compilation unit is already loaded, just mark it as
     used.  */
  if (per_cu->cu != NULL)
    {
      per_cu->cu->last_used = 0;
      return 0;
    }

  /* Add it to the queue.  */
  queue_comp_unit (per_cu, pretend_language);

  return 1;
}

/* Process the queue.  */

static void
process_queue (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  struct dwarf2_queue_item *item, *next_item;

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog,
			  "Expanding one or more symtabs of objfile %s ...\n",
			  objfile_name (dwarf2_per_objfile->objfile));
    }

  /* The queue starts out with one item, but following a DIE reference
     may load a new CU, adding it to the end of the queue.  */
  for (item = dwarf2_queue; item != NULL; dwarf2_queue = item = next_item)
    {
      if ((dwarf2_per_objfile->using_index
	   ? !item->per_cu->v.quick->compunit_symtab
	   : (item->per_cu->v.psymtab && !item->per_cu->v.psymtab->readin))
	  /* Skip dummy CUs.  */
	  && item->per_cu->cu != NULL)
	{
	  struct dwarf2_per_cu_data *per_cu = item->per_cu;
	  unsigned int debug_print_threshold;
	  char buf[100];

	  if (per_cu->is_debug_types)
	    {
	      struct signatured_type *sig_type =
		(struct signatured_type *) per_cu;

	      sprintf (buf, "TU %s at offset %s",
		       hex_string (sig_type->signature),
		       sect_offset_str (per_cu->sect_off));
	      /* There can be 100s of TUs.
		 Only print them in verbose mode.  */
	      debug_print_threshold = 2;
	    }
	  else
	    {
	      sprintf (buf, "CU at offset %s",
		       sect_offset_str (per_cu->sect_off));
	      debug_print_threshold = 1;
	    }

	  if (dwarf_read_debug >= debug_print_threshold)
	    fprintf_unfiltered (gdb_stdlog, "Expanding symtab of %s\n", buf);

	  if (per_cu->is_debug_types)
	    process_full_type_unit (per_cu, item->pretend_language);
	  else
	    process_full_comp_unit (per_cu, item->pretend_language);

	  if (dwarf_read_debug >= debug_print_threshold)
	    fprintf_unfiltered (gdb_stdlog, "Done expanding %s\n", buf);
	}

      item->per_cu->queued = 0;
      next_item = item->next;
      xfree (item);
    }

  dwarf2_queue_tail = NULL;

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Done expanding symtabs of %s.\n",
			  objfile_name (dwarf2_per_objfile->objfile));
    }
}

/* Read in full symbols for PST, and anything it depends on.  */

static void
psymtab_to_symtab_1 (struct partial_symtab *pst)
{
  struct dwarf2_per_cu_data *per_cu;
  int i;

  if (pst->readin)
    return;

  for (i = 0; i < pst->number_of_dependencies; i++)
    if (!pst->dependencies[i]->readin
	&& pst->dependencies[i]->user == NULL)
      {
        /* Inform about additional files that need to be read in.  */
        if (info_verbose)
          {
	    /* FIXME: i18n: Need to make this a single string.  */
            fputs_filtered (" ", gdb_stdout);
            wrap_here ("");
            fputs_filtered ("and ", gdb_stdout);
            wrap_here ("");
            printf_filtered ("%s...", pst->dependencies[i]->filename);
            wrap_here ("");     /* Flush output.  */
            gdb_flush (gdb_stdout);
          }
        psymtab_to_symtab_1 (pst->dependencies[i]);
      }

  per_cu = (struct dwarf2_per_cu_data *) pst->read_symtab_private;

  if (per_cu == NULL)
    {
      /* It's an include file, no symbols to read for it.
         Everything is in the parent symtab.  */
      pst->readin = 1;
      return;
    }

  dw2_do_instantiate_symtab (per_cu, false);
}

/* Trivial hash function for die_info: the hash value of a DIE
   is its offset in .debug_info for this objfile.  */

static hashval_t
die_hash (const void *item)
{
  const struct die_info *die = (const struct die_info *) item;

  return to_underlying (die->sect_off);
}

/* Trivial comparison function for die_info structures: two DIEs
   are equal if they have the same offset.  */

static int
die_eq (const void *item_lhs, const void *item_rhs)
{
  const struct die_info *die_lhs = (const struct die_info *) item_lhs;
  const struct die_info *die_rhs = (const struct die_info *) item_rhs;

  return die_lhs->sect_off == die_rhs->sect_off;
}

/* die_reader_func for load_full_comp_unit.
   This is identical to read_signatured_type_reader,
   but is kept separate for now.  */

static void
load_full_comp_unit_reader (const struct die_reader_specs *reader,
			    const gdb_byte *info_ptr,
			    struct die_info *comp_unit_die,
			    int has_children,
			    void *data)
{
  struct dwarf2_cu *cu = reader->cu;
  enum language *language_ptr = (enum language *) data;

  gdb_assert (cu->die_hash == NULL);
  cu->die_hash =
    htab_create_alloc_ex (cu->header.length / 12,
			  die_hash,
			  die_eq,
			  NULL,
			  &cu->comp_unit_obstack,
			  hashtab_obstack_allocate,
			  dummy_obstack_deallocate);

  if (has_children)
    comp_unit_die->child = read_die_and_siblings (reader, info_ptr,
						  &info_ptr, comp_unit_die);
  cu->dies = comp_unit_die;
  /* comp_unit_die is not stored in die_hash, no need.  */

  /* We try not to read any attributes in this function, because not
     all CUs needed for references have been loaded yet, and symbol
     table processing isn't initialized.  But we have to set the CU language,
     or we won't be able to build types correctly.
     Similarly, if we do not read the producer, we can not apply
     producer-specific interpretation.  */
  prepare_one_comp_unit (cu, cu->dies, *language_ptr);
}

/* Load the DIEs associated with PER_CU into memory.  */

static void
load_full_comp_unit (struct dwarf2_per_cu_data *this_cu,
		     bool skip_partial,
		     enum language pretend_language)
{
  gdb_assert (! this_cu->is_debug_types);

  init_cutu_and_read_dies (this_cu, NULL, 1, 1, skip_partial,
			   load_full_comp_unit_reader, &pretend_language);
}

/* Add a DIE to the delayed physname list.  */

static void
add_to_method_list (struct type *type, int fnfield_index, int index,
		    const char *name, struct die_info *die,
		    struct dwarf2_cu *cu)
{
  struct delayed_method_info mi;
  mi.type = type;
  mi.fnfield_index = fnfield_index;
  mi.index = index;
  mi.name = name;
  mi.die = die;
  cu->method_list.push_back (mi);
}

/* Check whether [PHYSNAME, PHYSNAME+LEN) ends with a modifier like
   "const" / "volatile".  If so, decrements LEN by the length of the
   modifier and return true.  Otherwise return false.  */

template<size_t N>
static bool
check_modifier (const char *physname, size_t &len, const char (&mod)[N])
{
  size_t mod_len = sizeof (mod) - 1;
  if (len > mod_len && startswith (physname + (len - mod_len), mod))
    {
      len -= mod_len;
      return true;
    }
  return false;
}

/* Compute the physnames of any methods on the CU's method list.

   The computation of method physnames is delayed in order to avoid the
   (bad) condition that one of the method's formal parameters is of an as yet
   incomplete type.  */

static void
compute_delayed_physnames (struct dwarf2_cu *cu)
{
  /* Only C++ delays computing physnames.  */
  if (cu->method_list.empty ())
    return;
  gdb_assert (cu->language == language_cplus);

  for (const delayed_method_info &mi : cu->method_list)
    {
      const char *physname;
      struct fn_fieldlist *fn_flp
	= &TYPE_FN_FIELDLIST (mi.type, mi.fnfield_index);
      physname = dwarf2_physname (mi.name, mi.die, cu);
      TYPE_FN_FIELD_PHYSNAME (fn_flp->fn_fields, mi.index)
	= physname ? physname : "";

      /* Since there's no tag to indicate whether a method is a
	 const/volatile overload, extract that information out of the
	 demangled name.  */
      if (physname != NULL)
	{
	  size_t len = strlen (physname);

	  while (1)
	    {
	      if (physname[len] == ')') /* shortcut */
		break;
	      else if (check_modifier (physname, len, " const"))
		TYPE_FN_FIELD_CONST (fn_flp->fn_fields, mi.index) = 1;
	      else if (check_modifier (physname, len, " volatile"))
		TYPE_FN_FIELD_VOLATILE (fn_flp->fn_fields, mi.index) = 1;
	      else
		break;
	    }
	}
    }

  /* The list is no longer needed.  */
  cu->method_list.clear ();
}

/* Go objects should be embedded in a DW_TAG_module DIE,
   and it's not clear if/how imported objects will appear.
   To keep Go support simple until that's worked out,
   go back through what we've read and create something usable.
   We could do this while processing each DIE, and feels kinda cleaner,
   but that way is more invasive.
   This is to, for example, allow the user to type "p var" or "b main"
   without having to specify the package name, and allow lookups
   of module.object to work in contexts that use the expression
   parser.  */

static void
fixup_go_packaging (struct dwarf2_cu *cu)
{
  char *package_name = NULL;
  struct pending *list;
  int i;

  for (list = *cu->get_builder ()->get_global_symbols ();
       list != NULL;
       list = list->next)
    {
      for (i = 0; i < list->nsyms; ++i)
	{
	  struct symbol *sym = list->symbol[i];

	  if (SYMBOL_LANGUAGE (sym) == language_go
	      && SYMBOL_CLASS (sym) == LOC_BLOCK)
	    {
	      char *this_package_name = go_symbol_package_name (sym);

	      if (this_package_name == NULL)
		continue;
	      if (package_name == NULL)
		package_name = this_package_name;
	      else
		{
		  struct objfile *objfile
		    = cu->per_cu->dwarf2_per_objfile->objfile;
		  if (strcmp (package_name, this_package_name) != 0)
		    complaint (_("Symtab %s has objects from two different Go packages: %s and %s"),
			       (symbol_symtab (sym) != NULL
				? symtab_to_filename_for_display
				    (symbol_symtab (sym))
				: objfile_name (objfile)),
			       this_package_name, package_name);
		  xfree (this_package_name);
		}
	    }
	}
    }

  if (package_name != NULL)
    {
      struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
      const char *saved_package_name
	= obstack_strdup (&objfile->per_bfd->storage_obstack, package_name);
      struct type *type = init_type (objfile, TYPE_CODE_MODULE, 0,
				     saved_package_name);
      struct symbol *sym;

      sym = allocate_symbol (objfile);
      SYMBOL_SET_LANGUAGE (sym, language_go, &objfile->objfile_obstack);
      SYMBOL_SET_NAMES (sym, saved_package_name, false, objfile);
      /* This is not VAR_DOMAIN because we want a way to ensure a lookup of,
	 e.g., "main" finds the "main" module and not C's main().  */
      SYMBOL_DOMAIN (sym) = STRUCT_DOMAIN;
      SYMBOL_ACLASS_INDEX (sym) = LOC_TYPEDEF;
      SYMBOL_TYPE (sym) = type;

      add_symbol_to_list (sym, cu->get_builder ()->get_global_symbols ());

      xfree (package_name);
    }
}

/* Allocate a fully-qualified name consisting of the two parts on the
   obstack.  */

static const char *
rust_fully_qualify (struct obstack *obstack, const char *p1, const char *p2)
{
  return obconcat (obstack, p1, "::", p2, (char *) NULL);
}

/* A helper that allocates a struct discriminant_info to attach to a
   union type.  */

static struct discriminant_info *
alloc_discriminant_info (struct type *type, int discriminant_index,
			 int default_index)
{
  gdb_assert (TYPE_CODE (type) == TYPE_CODE_UNION);
  gdb_assert (discriminant_index == -1
	      || (discriminant_index >= 0
		  && discriminant_index < TYPE_NFIELDS (type)));
  gdb_assert (default_index == -1
	      || (default_index >= 0 && default_index < TYPE_NFIELDS (type)));

  TYPE_FLAG_DISCRIMINATED_UNION (type) = 1;

  struct discriminant_info *disc
    = ((struct discriminant_info *)
       TYPE_ZALLOC (type,
		    offsetof (struct discriminant_info, discriminants)
		    + TYPE_NFIELDS (type) * sizeof (disc->discriminants[0])));
  disc->default_index = default_index;
  disc->discriminant_index = discriminant_index;

  struct dynamic_prop prop;
  prop.kind = PROP_UNDEFINED;
  prop.data.baton = disc;

  add_dyn_prop (DYN_PROP_DISCRIMINATED, prop, type);

  return disc;
}

/* Some versions of rustc emitted enums in an unusual way.

   Ordinary enums were emitted as unions.  The first element of each
   structure in the union was named "RUST$ENUM$DISR".  This element
   held the discriminant.

   These versions of Rust also implemented the "non-zero"
   optimization.  When the enum had two values, and one is empty and
   the other holds a pointer that cannot be zero, the pointer is used
   as the discriminant, with a zero value meaning the empty variant.
   Here, the union's first member is of the form
   RUST$ENCODED$ENUM$<fieldno>$<fieldno>$...$<variantname>
   where the fieldnos are the indices of the fields that should be
   traversed in order to find the field (which may be several fields deep)
   and the variantname is the name of the variant of the case when the
   field is zero.

   This function recognizes whether TYPE is of one of these forms,
   and, if so, smashes it to be a variant type.  */

static void
quirk_rust_enum (struct type *type, struct objfile *objfile)
{
  gdb_assert (TYPE_CODE (type) == TYPE_CODE_UNION);

  /* We don't need to deal with empty enums.  */
  if (TYPE_NFIELDS (type) == 0)
    return;

#define RUST_ENUM_PREFIX "RUST$ENCODED$ENUM$"
  if (TYPE_NFIELDS (type) == 1
      && startswith (TYPE_FIELD_NAME (type, 0), RUST_ENUM_PREFIX))
    {
      const char *name = TYPE_FIELD_NAME (type, 0) + strlen (RUST_ENUM_PREFIX);

      /* Decode the field name to find the offset of the
	 discriminant.  */
      ULONGEST bit_offset = 0;
      struct type *field_type = TYPE_FIELD_TYPE (type, 0);
      while (name[0] >= '0' && name[0] <= '9')
	{
	  char *tail;
	  unsigned long index = strtoul (name, &tail, 10);
	  name = tail;
	  if (*name != '$'
	      || index >= TYPE_NFIELDS (field_type)
	      || (TYPE_FIELD_LOC_KIND (field_type, index)
		  != FIELD_LOC_KIND_BITPOS))
	    {
	      complaint (_("Could not parse Rust enum encoding string \"%s\""
			   "[in module %s]"),
			 TYPE_FIELD_NAME (type, 0),
			 objfile_name (objfile));
	      return;
	    }
	  ++name;

	  bit_offset += TYPE_FIELD_BITPOS (field_type, index);
	  field_type = TYPE_FIELD_TYPE (field_type, index);
	}

      /* Make a union to hold the variants.  */
      struct type *union_type = alloc_type (objfile);
      TYPE_CODE (union_type) = TYPE_CODE_UNION;
      TYPE_NFIELDS (union_type) = 3;
      TYPE_FIELDS (union_type)
	= (struct field *) TYPE_ZALLOC (type, 3 * sizeof (struct field));
      TYPE_LENGTH (union_type) = TYPE_LENGTH (type);
      set_type_align (union_type, TYPE_RAW_ALIGN (type));

      /* Put the discriminant must at index 0.  */
      TYPE_FIELD_TYPE (union_type, 0) = field_type;
      TYPE_FIELD_ARTIFICIAL (union_type, 0) = 1;
      TYPE_FIELD_NAME (union_type, 0) = "<<discriminant>>";
      SET_FIELD_BITPOS (TYPE_FIELD (union_type, 0), bit_offset);

      /* The order of fields doesn't really matter, so put the real
	 field at index 1 and the data-less field at index 2.  */
      struct discriminant_info *disc
	= alloc_discriminant_info (union_type, 0, 1);
      TYPE_FIELD (union_type, 1) = TYPE_FIELD (type, 0);
      TYPE_FIELD_NAME (union_type, 1)
	= rust_last_path_segment (TYPE_NAME (TYPE_FIELD_TYPE (union_type, 1)));
      TYPE_NAME (TYPE_FIELD_TYPE (union_type, 1))
	= rust_fully_qualify (&objfile->objfile_obstack, TYPE_NAME (type),
			      TYPE_FIELD_NAME (union_type, 1));

      const char *dataless_name
	= rust_fully_qualify (&objfile->objfile_obstack, TYPE_NAME (type),
			      name);
      struct type *dataless_type = init_type (objfile, TYPE_CODE_VOID, 0,
					      dataless_name);
      TYPE_FIELD_TYPE (union_type, 2) = dataless_type;
      /* NAME points into the original discriminant name, which
	 already has the correct lifetime.  */
      TYPE_FIELD_NAME (union_type, 2) = name;
      SET_FIELD_BITPOS (TYPE_FIELD (union_type, 2), 0);
      disc->discriminants[2] = 0;

      /* Smash this type to be a structure type.  We have to do this
	 because the type has already been recorded.  */
      TYPE_CODE (type) = TYPE_CODE_STRUCT;
      TYPE_NFIELDS (type) = 1;
      TYPE_FIELDS (type)
	= (struct field *) TYPE_ZALLOC (type, sizeof (struct field));

      /* Install the variant part.  */
      TYPE_FIELD_TYPE (type, 0) = union_type;
      SET_FIELD_BITPOS (TYPE_FIELD (type, 0), 0);
      TYPE_FIELD_NAME (type, 0) = "<<variants>>";
    }
  /* A union with a single anonymous field is probably an old-style
     univariant enum.  */
  else if (TYPE_NFIELDS (type) == 1 && streq (TYPE_FIELD_NAME (type, 0), ""))
    {
      /* Smash this type to be a structure type.  We have to do this
	 because the type has already been recorded.  */
      TYPE_CODE (type) = TYPE_CODE_STRUCT;

      /* Make a union to hold the variants.  */
      struct type *union_type = alloc_type (objfile);
      TYPE_CODE (union_type) = TYPE_CODE_UNION;
      TYPE_NFIELDS (union_type) = TYPE_NFIELDS (type);
      TYPE_LENGTH (union_type) = TYPE_LENGTH (type);
      set_type_align (union_type, TYPE_RAW_ALIGN (type));
      TYPE_FIELDS (union_type) = TYPE_FIELDS (type);

      struct type *field_type = TYPE_FIELD_TYPE (union_type, 0);
      const char *variant_name
	= rust_last_path_segment (TYPE_NAME (field_type));
      TYPE_FIELD_NAME (union_type, 0) = variant_name;
      TYPE_NAME (field_type)
	= rust_fully_qualify (&objfile->objfile_obstack,
			      TYPE_NAME (type), variant_name);

      /* Install the union in the outer struct type.  */
      TYPE_NFIELDS (type) = 1;
      TYPE_FIELDS (type)
	= (struct field *) TYPE_ZALLOC (union_type, sizeof (struct field));
      TYPE_FIELD_TYPE (type, 0) = union_type;
      TYPE_FIELD_NAME (type, 0) = "<<variants>>";
      SET_FIELD_BITPOS (TYPE_FIELD (type, 0), 0);

      alloc_discriminant_info (union_type, -1, 0);
    }
  else
    {
      struct type *disr_type = nullptr;
      for (int i = 0; i < TYPE_NFIELDS (type); ++i)
	{
	  disr_type = TYPE_FIELD_TYPE (type, i);

	  if (TYPE_CODE (disr_type) != TYPE_CODE_STRUCT)
	    {
	      /* All fields of a true enum will be structs.  */
	      return;
	    }
	  else if (TYPE_NFIELDS (disr_type) == 0)
	    {
	      /* Could be data-less variant, so keep going.  */
	      disr_type = nullptr;
	    }
	  else if (strcmp (TYPE_FIELD_NAME (disr_type, 0),
			   "RUST$ENUM$DISR") != 0)
	    {
	      /* Not a Rust enum.  */
	      return;
	    }
	  else
	    {
	      /* Found one.  */
	      break;
	    }
	}

      /* If we got here without a discriminant, then it's probably
	 just a union.  */
      if (disr_type == nullptr)
	return;

      /* Smash this type to be a structure type.  We have to do this
	 because the type has already been recorded.  */
      TYPE_CODE (type) = TYPE_CODE_STRUCT;

      /* Make a union to hold the variants.  */
      struct field *disr_field = &TYPE_FIELD (disr_type, 0);
      struct type *union_type = alloc_type (objfile);
      TYPE_CODE (union_type) = TYPE_CODE_UNION;
      TYPE_NFIELDS (union_type) = 1 + TYPE_NFIELDS (type);
      TYPE_LENGTH (union_type) = TYPE_LENGTH (type);
      set_type_align (union_type, TYPE_RAW_ALIGN (type));
      TYPE_FIELDS (union_type)
	= (struct field *) TYPE_ZALLOC (union_type,
					(TYPE_NFIELDS (union_type)
					 * sizeof (struct field)));

      memcpy (TYPE_FIELDS (union_type) + 1, TYPE_FIELDS (type),
	      TYPE_NFIELDS (type) * sizeof (struct field));

      /* Install the discriminant at index 0 in the union.  */
      TYPE_FIELD (union_type, 0) = *disr_field;
      TYPE_FIELD_ARTIFICIAL (union_type, 0) = 1;
      TYPE_FIELD_NAME (union_type, 0) = "<<discriminant>>";

      /* Install the union in the outer struct type.  */
      TYPE_FIELD_TYPE (type, 0) = union_type;
      TYPE_FIELD_NAME (type, 0) = "<<variants>>";
      TYPE_NFIELDS (type) = 1;

      /* Set the size and offset of the union type.  */
      SET_FIELD_BITPOS (TYPE_FIELD (type, 0), 0);

      /* We need a way to find the correct discriminant given a
	 variant name.  For convenience we build a map here.  */
      struct type *enum_type = FIELD_TYPE (*disr_field);
      std::unordered_map<std::string, ULONGEST> discriminant_map;
      for (int i = 0; i < TYPE_NFIELDS (enum_type); ++i)
	{
	  if (TYPE_FIELD_LOC_KIND (enum_type, i) == FIELD_LOC_KIND_ENUMVAL)
	    {
	      const char *name
		= rust_last_path_segment (TYPE_FIELD_NAME (enum_type, i));
	      discriminant_map[name] = TYPE_FIELD_ENUMVAL (enum_type, i);
	    }
	}

      int n_fields = TYPE_NFIELDS (union_type);
      struct discriminant_info *disc
	= alloc_discriminant_info (union_type, 0, -1);
      /* Skip the discriminant here.  */
      for (int i = 1; i < n_fields; ++i)
	{
	  /* Find the final word in the name of this variant's type.
	     That name can be used to look up the correct
	     discriminant.  */
	  const char *variant_name
	    = rust_last_path_segment (TYPE_NAME (TYPE_FIELD_TYPE (union_type,
								  i)));

	  auto iter = discriminant_map.find (variant_name);
	  if (iter != discriminant_map.end ())
	    disc->discriminants[i] = iter->second;

	  /* Remove the discriminant field, if it exists.  */
	  struct type *sub_type = TYPE_FIELD_TYPE (union_type, i);
	  if (TYPE_NFIELDS (sub_type) > 0)
	    {
	      --TYPE_NFIELDS (sub_type);
	      ++TYPE_FIELDS (sub_type);
	    }
	  TYPE_FIELD_NAME (union_type, i) = variant_name;
	  TYPE_NAME (sub_type)
	    = rust_fully_qualify (&objfile->objfile_obstack,
				  TYPE_NAME (type), variant_name);
	}
    }
}

/* Rewrite some Rust unions to be structures with variants parts.  */

static void
rust_union_quirks (struct dwarf2_cu *cu)
{
  gdb_assert (cu->language == language_rust);
  for (type *type_ : cu->rust_unions)
    quirk_rust_enum (type_, cu->per_cu->dwarf2_per_objfile->objfile);
  /* We don't need this any more.  */
  cu->rust_unions.clear ();
}

/* Return the symtab for PER_CU.  This works properly regardless of
   whether we're using the index or psymtabs.  */

static struct compunit_symtab *
get_compunit_symtab (struct dwarf2_per_cu_data *per_cu)
{
  return (per_cu->dwarf2_per_objfile->using_index
	  ? per_cu->v.quick->compunit_symtab
	  : per_cu->v.psymtab->compunit_symtab);
}

/* A helper function for computing the list of all symbol tables
   included by PER_CU.  */

static void
recursively_compute_inclusions (std::vector<compunit_symtab *> *result,
				htab_t all_children, htab_t all_type_symtabs,
				struct dwarf2_per_cu_data *per_cu,
				struct compunit_symtab *immediate_parent)
{
  void **slot;
  struct compunit_symtab *cust;

  slot = htab_find_slot (all_children, per_cu, INSERT);
  if (*slot != NULL)
    {
      /* This inclusion and its children have been processed.  */
      return;
    }

  *slot = per_cu;
  /* Only add a CU if it has a symbol table.  */
  cust = get_compunit_symtab (per_cu);
  if (cust != NULL)
    {
      /* If this is a type unit only add its symbol table if we haven't
	 seen it yet (type unit per_cu's can share symtabs).  */
      if (per_cu->is_debug_types)
	{
	  slot = htab_find_slot (all_type_symtabs, cust, INSERT);
	  if (*slot == NULL)
	    {
	      *slot = cust;
	      result->push_back (cust);
	      if (cust->user == NULL)
		cust->user = immediate_parent;
	    }
	}
      else
	{
	  result->push_back (cust);
	  if (cust->user == NULL)
	    cust->user = immediate_parent;
	}
    }

  if (!per_cu->imported_symtabs_empty ())
    for (dwarf2_per_cu_data *ptr : *per_cu->imported_symtabs)
      {
	recursively_compute_inclusions (result, all_children,
					all_type_symtabs, ptr, cust);
      }
}

/* Compute the compunit_symtab 'includes' fields for the compunit_symtab of
   PER_CU.  */

static void
compute_compunit_symtab_includes (struct dwarf2_per_cu_data *per_cu)
{
  gdb_assert (! per_cu->is_debug_types);

  if (!per_cu->imported_symtabs_empty ())
    {
      int len;
      std::vector<compunit_symtab *> result_symtabs;
      htab_t all_children, all_type_symtabs;
      struct compunit_symtab *cust = get_compunit_symtab (per_cu);

      /* If we don't have a symtab, we can just skip this case.  */
      if (cust == NULL)
	return;

      all_children = htab_create_alloc (1, htab_hash_pointer, htab_eq_pointer,
					NULL, xcalloc, xfree);
      all_type_symtabs = htab_create_alloc (1, htab_hash_pointer, htab_eq_pointer,
					    NULL, xcalloc, xfree);

      for (dwarf2_per_cu_data *ptr : *per_cu->imported_symtabs)
	{
	  recursively_compute_inclusions (&result_symtabs, all_children,
					  all_type_symtabs, ptr, cust);
	}

      /* Now we have a transitive closure of all the included symtabs.  */
      len = result_symtabs.size ();
      cust->includes
	= XOBNEWVEC (&per_cu->dwarf2_per_objfile->objfile->objfile_obstack,
		     struct compunit_symtab *, len + 1);
      memcpy (cust->includes, result_symtabs.data (),
	      len * sizeof (compunit_symtab *));
      cust->includes[len] = NULL;

      htab_delete (all_children);
      htab_delete (all_type_symtabs);
    }
}

/* Compute the 'includes' field for the symtabs of all the CUs we just
   read.  */

static void
process_cu_includes (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  for (dwarf2_per_cu_data *iter : dwarf2_per_objfile->just_read_cus)
    {
      if (! iter->is_debug_types)
	compute_compunit_symtab_includes (iter);
    }

  dwarf2_per_objfile->just_read_cus.clear ();
}

/* Generate full symbol information for PER_CU, whose DIEs have
   already been loaded into memory.  */

static void
process_full_comp_unit (struct dwarf2_per_cu_data *per_cu,
			enum language pretend_language)
{
  struct dwarf2_cu *cu = per_cu->cu;
  struct dwarf2_per_objfile *dwarf2_per_objfile = per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  CORE_ADDR lowpc, highpc;
  struct compunit_symtab *cust;
  CORE_ADDR baseaddr;
  struct block *static_block;
  CORE_ADDR addr;

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  /* Clear the list here in case something was left over.  */
  cu->method_list.clear ();

  cu->language = pretend_language;
  cu->language_defn = language_def (cu->language);

  /* Do line number decoding in read_file_scope () */
  process_die (cu->dies, cu);

  /* For now fudge the Go package.  */
  if (cu->language == language_go)
    fixup_go_packaging (cu);

  /* Now that we have processed all the DIEs in the CU, all the types
     should be complete, and it should now be safe to compute all of the
     physnames.  */
  compute_delayed_physnames (cu);

  if (cu->language == language_rust)
    rust_union_quirks (cu);

  /* Some compilers don't define a DW_AT_high_pc attribute for the
     compilation unit.  If the DW_AT_high_pc is missing, synthesize
     it, by scanning the DIE's below the compilation unit.  */
  get_scope_pc_bounds (cu->dies, &lowpc, &highpc, cu);

  addr = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);
  static_block = cu->get_builder ()->end_symtab_get_static_block (addr, 0, 1);

  /* If the comp unit has DW_AT_ranges, it may have discontiguous ranges.
     Also, DW_AT_ranges may record ranges not belonging to any child DIEs
     (such as virtual method tables).  Record the ranges in STATIC_BLOCK's
     addrmap to help ensure it has an accurate map of pc values belonging to
     this comp unit.  */
  dwarf2_record_block_ranges (cu->dies, static_block, baseaddr, cu);

  cust = cu->get_builder ()->end_symtab_from_static_block (static_block,
						    SECT_OFF_TEXT (objfile),
						    0);

  if (cust != NULL)
    {
      int gcc_4_minor = producer_is_gcc_ge_4 (cu->producer);

      /* Set symtab language to language from DW_AT_language.  If the
	 compilation is from a C file generated by language preprocessors, do
	 not set the language if it was already deduced by start_subfile.  */
      if (!(cu->language == language_c
	    && COMPUNIT_FILETABS (cust)->language != language_unknown))
	COMPUNIT_FILETABS (cust)->language = cu->language;

      /* GCC-4.0 has started to support -fvar-tracking.  GCC-3.x still can
	 produce DW_AT_location with location lists but it can be possibly
	 invalid without -fvar-tracking.  Still up to GCC-4.4.x incl. 4.4.0
	 there were bugs in prologue debug info, fixed later in GCC-4.5
	 by "unwind info for epilogues" patch (which is not directly related).

	 For -gdwarf-4 type units LOCATIONS_VALID indication is fortunately not
	 needed, it would be wrong due to missing DW_AT_producer there.

	 Still one can confuse GDB by using non-standard GCC compilation
	 options - this waits on GCC PR other/32998 (-frecord-gcc-switches).
	 */
      if (cu->has_loclist && gcc_4_minor >= 5)
	cust->locations_valid = 1;

      if (gcc_4_minor >= 5)
	cust->epilogue_unwind_valid = 1;

      cust->call_site_htab = cu->call_site_htab;
    }

  if (dwarf2_per_objfile->using_index)
    per_cu->v.quick->compunit_symtab = cust;
  else
    {
      struct partial_symtab *pst = per_cu->v.psymtab;
      pst->compunit_symtab = cust;
      pst->readin = 1;
    }

  /* Push it for inclusion processing later.  */
  dwarf2_per_objfile->just_read_cus.push_back (per_cu);

  /* Not needed any more.  */
  cu->reset_builder ();
}

/* Generate full symbol information for type unit PER_CU, whose DIEs have
   already been loaded into memory.  */

static void
process_full_type_unit (struct dwarf2_per_cu_data *per_cu,
			enum language pretend_language)
{
  struct dwarf2_cu *cu = per_cu->cu;
  struct dwarf2_per_objfile *dwarf2_per_objfile = per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct compunit_symtab *cust;
  struct signatured_type *sig_type;

  gdb_assert (per_cu->is_debug_types);
  sig_type = (struct signatured_type *) per_cu;

  /* Clear the list here in case something was left over.  */
  cu->method_list.clear ();

  cu->language = pretend_language;
  cu->language_defn = language_def (cu->language);

  /* The symbol tables are set up in read_type_unit_scope.  */
  process_die (cu->dies, cu);

  /* For now fudge the Go package.  */
  if (cu->language == language_go)
    fixup_go_packaging (cu);

  /* Now that we have processed all the DIEs in the CU, all the types
     should be complete, and it should now be safe to compute all of the
     physnames.  */
  compute_delayed_physnames (cu);

  if (cu->language == language_rust)
    rust_union_quirks (cu);

  /* TUs share symbol tables.
     If this is the first TU to use this symtab, complete the construction
     of it with end_expandable_symtab.  Otherwise, complete the addition of
     this TU's symbols to the existing symtab.  */
  if (sig_type->type_unit_group->compunit_symtab == NULL)
    {
      buildsym_compunit *builder = cu->get_builder ();
      cust = builder->end_expandable_symtab (0, SECT_OFF_TEXT (objfile));
      sig_type->type_unit_group->compunit_symtab = cust;

      if (cust != NULL)
	{
	  /* Set symtab language to language from DW_AT_language.  If the
	     compilation is from a C file generated by language preprocessors,
	     do not set the language if it was already deduced by
	     start_subfile.  */
	  if (!(cu->language == language_c
		&& COMPUNIT_FILETABS (cust)->language != language_c))
	    COMPUNIT_FILETABS (cust)->language = cu->language;
	}
    }
  else
    {
      cu->get_builder ()->augment_type_symtab ();
      cust = sig_type->type_unit_group->compunit_symtab;
    }

  if (dwarf2_per_objfile->using_index)
    per_cu->v.quick->compunit_symtab = cust;
  else
    {
      struct partial_symtab *pst = per_cu->v.psymtab;
      pst->compunit_symtab = cust;
      pst->readin = 1;
    }

  /* Not needed any more.  */
  cu->reset_builder ();
}

/* Process an imported unit DIE.  */

static void
process_imported_unit_die (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr;

  /* For now we don't handle imported units in type units.  */
  if (cu->per_cu->is_debug_types)
    {
      error (_("Dwarf Error: DW_TAG_imported_unit is not"
	       " supported in type units [in module %s]"),
	     objfile_name (cu->per_cu->dwarf2_per_objfile->objfile));
    }

  attr = dwarf2_attr (die, DW_AT_import, cu);
  if (attr != NULL)
    {
      sect_offset sect_off = dwarf2_get_ref_die_offset (attr);
      bool is_dwz = (attr->form == DW_FORM_GNU_ref_alt || cu->per_cu->is_dwz);
      dwarf2_per_cu_data *per_cu
	= dwarf2_find_containing_comp_unit (sect_off, is_dwz,
					    cu->per_cu->dwarf2_per_objfile);

      /* If necessary, add it to the queue and load its DIEs.  */
      if (maybe_queue_comp_unit (cu, per_cu, cu->language))
	load_full_comp_unit (per_cu, false, cu->language);

      cu->per_cu->imported_symtabs_push (per_cu);
    }
}

/* RAII object that represents a process_die scope: i.e.,
   starts/finishes processing a DIE.  */
class process_die_scope
{
public:
  process_die_scope (die_info *die, dwarf2_cu *cu)
    : m_die (die), m_cu (cu)
  {
    /* We should only be processing DIEs not already in process.  */
    gdb_assert (!m_die->in_process);
    m_die->in_process = true;
  }

  ~process_die_scope ()
  {
    m_die->in_process = false;

    /* If we're done processing the DIE for the CU that owns the line
       header, we don't need the line header anymore.  */
    if (m_cu->line_header_die_owner == m_die)
      {
	delete m_cu->line_header;
	m_cu->line_header = NULL;
	m_cu->line_header_die_owner = NULL;
      }
  }

private:
  die_info *m_die;
  dwarf2_cu *m_cu;
};

/* Process a die and its children.  */

static void
process_die (struct die_info *die, struct dwarf2_cu *cu)
{
  process_die_scope scope (die, cu);

  switch (die->tag)
    {
    case DW_TAG_padding:
      break;
    case DW_TAG_compile_unit:
    case DW_TAG_partial_unit:
    case DW_TAG_skeleton_unit:
      read_file_scope (die, cu);
      break;
    case DW_TAG_type_unit:
      read_type_unit_scope (die, cu);
      break;
    case DW_TAG_subprogram:
      /* Nested subprograms in Fortran get a prefix.  */
      if (cu->language == language_fortran
	  && die->parent != NULL
	  && die->parent->tag == DW_TAG_subprogram)
	cu->processing_has_namespace_info = true;
      /* Fall through.  */
    case DW_TAG_inlined_subroutine:
      read_func_scope (die, cu);
      break;
    case DW_TAG_lexical_block:
    case DW_TAG_try_block:
    case DW_TAG_catch_block:
      read_lexical_block_scope (die, cu);
      break;
    case DW_TAG_call_site:
    case DW_TAG_GNU_call_site:
      read_call_site_scope (die, cu);
      break;
    case DW_TAG_class_type:
    case DW_TAG_interface_type:
    case DW_TAG_structure_type:
    case DW_TAG_union_type:
      process_structure_scope (die, cu);
      break;
    case DW_TAG_enumeration_type:
      process_enumeration_scope (die, cu);
      break;

    /* These dies have a type, but processing them does not create
       a symbol or recurse to process the children.  Therefore we can
       read them on-demand through read_type_die.  */
    case DW_TAG_subroutine_type:
    case DW_TAG_set_type:
    case DW_TAG_array_type:
    case DW_TAG_pointer_type:
    case DW_TAG_ptr_to_member_type:
    case DW_TAG_reference_type:
    case DW_TAG_rvalue_reference_type:
    case DW_TAG_string_type:
      break;

    case DW_TAG_base_type:
    case DW_TAG_subrange_type:
    case DW_TAG_typedef:
      /* Add a typedef symbol for the type definition, if it has a
         DW_AT_name.  */
      new_symbol (die, read_type_die (die, cu), cu);
      break;
    case DW_TAG_common_block:
      read_common_block (die, cu);
      break;
    case DW_TAG_common_inclusion:
      break;
    case DW_TAG_namespace:
      cu->processing_has_namespace_info = true;
      read_namespace (die, cu);
      break;
    case DW_TAG_module:
      cu->processing_has_namespace_info = true;
      read_module (die, cu);
      break;
    case DW_TAG_imported_declaration:
      cu->processing_has_namespace_info = true;
      if (read_namespace_alias (die, cu))
	break;
      /* The declaration is not a global namespace alias.  */
      /* Fall through.  */
    case DW_TAG_imported_module:
      cu->processing_has_namespace_info = true;
      if (die->child != NULL && (die->tag == DW_TAG_imported_declaration
				 || cu->language != language_fortran))
	complaint (_("Tag '%s' has unexpected children"),
		   dwarf_tag_name (die->tag));
      read_import_statement (die, cu);
      break;

    case DW_TAG_imported_unit:
      process_imported_unit_die (die, cu);
      break;

    case DW_TAG_variable:
      read_variable (die, cu);
      break;

    default:
      new_symbol (die, NULL, cu);
      break;
    }
}

/* DWARF name computation.  */

/* A helper function for dwarf2_compute_name which determines whether DIE
   needs to have the name of the scope prepended to the name listed in the
   die.  */

static int
die_needs_namespace (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr;

  switch (die->tag)
    {
    case DW_TAG_namespace:
    case DW_TAG_typedef:
    case DW_TAG_class_type:
    case DW_TAG_interface_type:
    case DW_TAG_structure_type:
    case DW_TAG_union_type:
    case DW_TAG_enumeration_type:
    case DW_TAG_enumerator:
    case DW_TAG_subprogram:
    case DW_TAG_inlined_subroutine:
    case DW_TAG_member:
    case DW_TAG_imported_declaration:
      return 1;

    case DW_TAG_variable:
    case DW_TAG_constant:
      /* We only need to prefix "globally" visible variables.  These include
	 any variable marked with DW_AT_external or any variable that
	 lives in a namespace.  [Variables in anonymous namespaces
	 require prefixing, but they are not DW_AT_external.]  */

      if (dwarf2_attr (die, DW_AT_specification, cu))
	{
	  struct dwarf2_cu *spec_cu = cu;

	  return die_needs_namespace (die_specification (die, &spec_cu),
				      spec_cu);
	}

      attr = dwarf2_attr (die, DW_AT_external, cu);
      if (attr == NULL && die->parent->tag != DW_TAG_namespace
	  && die->parent->tag != DW_TAG_module)
	return 0;
      /* A variable in a lexical block of some kind does not need a
	 namespace, even though in C++ such variables may be external
	 and have a mangled name.  */
      if (die->parent->tag ==  DW_TAG_lexical_block
	  || die->parent->tag ==  DW_TAG_try_block
	  || die->parent->tag ==  DW_TAG_catch_block
	  || die->parent->tag == DW_TAG_subprogram)
	return 0;
      return 1;

    default:
      return 0;
    }
}

/* Return the DIE's linkage name attribute, either DW_AT_linkage_name
   or DW_AT_MIPS_linkage_name.  Returns NULL if the attribute is not
   defined for the given DIE.  */

static struct attribute *
dw2_linkage_name_attr (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr;

  attr = dwarf2_attr (die, DW_AT_linkage_name, cu);
  if (attr == NULL)
    attr = dwarf2_attr (die, DW_AT_MIPS_linkage_name, cu);

  return attr;
}

/* Return the DIE's linkage name as a string, either DW_AT_linkage_name
   or DW_AT_MIPS_linkage_name.  Returns NULL if the attribute is not
   defined for the given DIE.  */

static const char *
dw2_linkage_name (struct die_info *die, struct dwarf2_cu *cu)
{
  const char *linkage_name;

  linkage_name = dwarf2_string_attr (die, DW_AT_linkage_name, cu);
  if (linkage_name == NULL)
    linkage_name = dwarf2_string_attr (die, DW_AT_MIPS_linkage_name, cu);

  return linkage_name;
}

/* Compute the fully qualified name of DIE in CU.  If PHYSNAME is nonzero,
   compute the physname for the object, which include a method's:
   - formal parameters (C++),
   - receiver type (Go),

   The term "physname" is a bit confusing.
   For C++, for example, it is the demangled name.
   For Go, for example, it's the mangled name.

   For Ada, return the DIE's linkage name rather than the fully qualified
   name.  PHYSNAME is ignored..

   The result is allocated on the objfile_obstack and canonicalized.  */

static const char *
dwarf2_compute_name (const char *name,
		     struct die_info *die, struct dwarf2_cu *cu,
		     int physname)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;

  if (name == NULL)
    name = dwarf2_name (die, cu);

  /* For Fortran GDB prefers DW_AT_*linkage_name for the physname if present
     but otherwise compute it by typename_concat inside GDB.
     FIXME: Actually this is not really true, or at least not always true.
     It's all very confusing.  SYMBOL_SET_NAMES doesn't try to demangle
     Fortran names because there is no mangling standard.  So new_symbol
     will set the demangled name to the result of dwarf2_full_name, and it is
     the demangled name that GDB uses if it exists.  */
  if (cu->language == language_ada
      || (cu->language == language_fortran && physname))
    {
      /* For Ada unit, we prefer the linkage name over the name, as
	 the former contains the exported name, which the user expects
	 to be able to reference.  Ideally, we want the user to be able
	 to reference this entity using either natural or linkage name,
	 but we haven't started looking at this enhancement yet.  */
      const char *linkage_name = dw2_linkage_name (die, cu);

      if (linkage_name != NULL)
	return linkage_name;
    }

  /* These are the only languages we know how to qualify names in.  */
  if (name != NULL
      && (cu->language == language_cplus
	  || cu->language == language_fortran || cu->language == language_d
	  || cu->language == language_rust))
    {
      if (die_needs_namespace (die, cu))
	{
	  const char *prefix;
	  const char *canonical_name = NULL;

	  string_file buf;

	  prefix = determine_prefix (die, cu);
	  if (*prefix != '\0')
	    {
	      char *prefixed_name = typename_concat (NULL, prefix, name,
						     physname, cu);

	      buf.puts (prefixed_name);
	      xfree (prefixed_name);
	    }
	  else
	    buf.puts (name);

	  /* Template parameters may be specified in the DIE's DW_AT_name, or
	     as children with DW_TAG_template_type_param or
	     DW_TAG_value_type_param.  If the latter, add them to the name
	     here.  If the name already has template parameters, then
	     skip this step; some versions of GCC emit both, and
	     it is more efficient to use the pre-computed name.

	     Something to keep in mind about this process: it is very
	     unlikely, or in some cases downright impossible, to produce
	     something that will match the mangled name of a function.
	     If the definition of the function has the same debug info,
	     we should be able to match up with it anyway.  But fallbacks
	     using the minimal symbol, for instance to find a method
	     implemented in a stripped copy of libstdc++, will not work.
	     If we do not have debug info for the definition, we will have to
	     match them up some other way.

	     When we do name matching there is a related problem with function
	     templates; two instantiated function templates are allowed to
	     differ only by their return types, which we do not add here.  */

	  if (cu->language == language_cplus && strchr (name, '<') == NULL)
	    {
	      struct attribute *attr;
	      struct die_info *child;
	      int first = 1;

	      die->building_fullname = 1;

	      for (child = die->child; child != NULL; child = child->sibling)
		{
		  struct type *type;
		  LONGEST value;
		  const gdb_byte *bytes;
		  struct dwarf2_locexpr_baton *baton;
		  struct value *v;

		  if (child->tag != DW_TAG_template_type_param
		      && child->tag != DW_TAG_template_value_param)
		    continue;

		  if (first)
		    {
		      buf.puts ("<");
		      first = 0;
		    }
		  else
		    buf.puts (", ");

		  attr = dwarf2_attr (child, DW_AT_type, cu);
		  if (attr == NULL)
		    {
		      complaint (_("template parameter missing DW_AT_type"));
		      buf.puts ("UNKNOWN_TYPE");
		      continue;
		    }
		  type = die_type (child, cu);

		  if (child->tag == DW_TAG_template_type_param)
		    {
		      c_print_type (type, "", &buf, -1, 0, cu->language,
				    &type_print_raw_options);
		      continue;
		    }

		  attr = dwarf2_attr (child, DW_AT_const_value, cu);
		  if (attr == NULL)
		    {
		      complaint (_("template parameter missing "
				   "DW_AT_const_value"));
		      buf.puts ("UNKNOWN_VALUE");
		      continue;
		    }

		  dwarf2_const_value_attr (attr, type, name,
					   &cu->comp_unit_obstack, cu,
					   &value, &bytes, &baton);

		  if (TYPE_NOSIGN (type))
		    /* GDB prints characters as NUMBER 'CHAR'.  If that's
		       changed, this can use value_print instead.  */
		    c_printchar (value, type, &buf);
		  else
		    {
		      struct value_print_options opts;

		      if (baton != NULL)
			v = dwarf2_evaluate_loc_desc (type, NULL,
						      baton->data,
						      baton->size,
						      baton->per_cu);
		      else if (bytes != NULL)
			{
			  v = allocate_value (type);
			  memcpy (value_contents_writeable (v), bytes,
				  TYPE_LENGTH (type));
			}
		      else
			v = value_from_longest (type, value);

		      /* Specify decimal so that we do not depend on
			 the radix.  */
		      get_formatted_print_options (&opts, 'd');
		      opts.raw = 1;
		      value_print (v, &buf, &opts);
		      release_value (v);
		    }
		}

	      die->building_fullname = 0;

	      if (!first)
		{
		  /* Close the argument list, with a space if necessary
		     (nested templates).  */
		  if (!buf.empty () && buf.string ().back () == '>')
		    buf.puts (" >");
		  else
		    buf.puts (">");
		}
	    }

	  /* For C++ methods, append formal parameter type
	     information, if PHYSNAME.  */

	  if (physname && die->tag == DW_TAG_subprogram
	      && cu->language == language_cplus)
	    {
	      struct type *type = read_type_die (die, cu);

	      c_type_print_args (type, &buf, 1, cu->language,
				 &type_print_raw_options);

	      if (cu->language == language_cplus)
		{
		  /* Assume that an artificial first parameter is
		     "this", but do not crash if it is not.  RealView
		     marks unnamed (and thus unused) parameters as
		     artificial; there is no way to differentiate
		     the two cases.  */
		  if (TYPE_NFIELDS (type) > 0
		      && TYPE_FIELD_ARTIFICIAL (type, 0)
		      && TYPE_CODE (TYPE_FIELD_TYPE (type, 0)) == TYPE_CODE_PTR
		      && TYPE_CONST (TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (type,
									0))))
		    buf.puts (" const");
		}
	    }

	  const std::string &intermediate_name = buf.string ();

	  if (cu->language == language_cplus)
	    canonical_name
	      = dwarf2_canonicalize_name (intermediate_name.c_str (), cu,
					  &objfile->per_bfd->storage_obstack);

	  /* If we only computed INTERMEDIATE_NAME, or if
	     INTERMEDIATE_NAME is already canonical, then we need to
	     copy it to the appropriate obstack.  */
	  if (canonical_name == NULL || canonical_name == intermediate_name.c_str ())
	    name = obstack_strdup (&objfile->per_bfd->storage_obstack,
				   intermediate_name);
	  else
	    name = canonical_name;
	}
    }

  return name;
}

/* Return the fully qualified name of DIE, based on its DW_AT_name.
   If scope qualifiers are appropriate they will be added.  The result
   will be allocated on the storage_obstack, or NULL if the DIE does
   not have a name.  NAME may either be from a previous call to
   dwarf2_name or NULL.

   The output string will be canonicalized (if C++).  */

static const char *
dwarf2_full_name (const char *name, struct die_info *die, struct dwarf2_cu *cu)
{
  return dwarf2_compute_name (name, die, cu, 0);
}

/* Construct a physname for the given DIE in CU.  NAME may either be
   from a previous call to dwarf2_name or NULL.  The result will be
   allocated on the objfile_objstack or NULL if the DIE does not have a
   name.

   The output string will be canonicalized (if C++).  */

static const char *
dwarf2_physname (const char *name, struct die_info *die, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  const char *retval, *mangled = NULL, *canon = NULL;
  int need_copy = 1;

  /* In this case dwarf2_compute_name is just a shortcut not building anything
     on its own.  */
  if (!die_needs_namespace (die, cu))
    return dwarf2_compute_name (name, die, cu, 1);

  mangled = dw2_linkage_name (die, cu);

  /* rustc emits invalid values for DW_AT_linkage_name.  Ignore these.
     See https://github.com/rust-lang/rust/issues/32925.  */
  if (cu->language == language_rust && mangled != NULL
      && strchr (mangled, '{') != NULL)
    mangled = NULL;

  /* DW_AT_linkage_name is missing in some cases - depend on what GDB
     has computed.  */
  gdb::unique_xmalloc_ptr<char> demangled;
  if (mangled != NULL)
    {

      if (language_def (cu->language)->la_store_sym_names_in_linkage_form_p)
	{
	  /* Do nothing (do not demangle the symbol name).  */
	}
      else if (cu->language == language_go)
	{
	  /* This is a lie, but we already lie to the caller new_symbol.
	     new_symbol assumes we return the mangled name.
	     This just undoes that lie until things are cleaned up.  */
	}
      else
	{
	  /* Use DMGL_RET_DROP for C++ template functions to suppress
	     their return type.  It is easier for GDB users to search
	     for such functions as `name(params)' than `long name(params)'.
	     In such case the minimal symbol names do not match the full
	     symbol names but for template functions there is never a need
	     to look up their definition from their declaration so
	     the only disadvantage remains the minimal symbol variant
	     `long name(params)' does not have the proper inferior type.  */
	  demangled.reset (gdb_demangle (mangled,
					 (DMGL_PARAMS | DMGL_ANSI
					  | DMGL_RET_DROP)));
	}
      if (demangled)
	canon = demangled.get ();
      else
	{
	  canon = mangled;
	  need_copy = 0;
	}
    }

  if (canon == NULL || check_physname)
    {
      const char *physname = dwarf2_compute_name (name, die, cu, 1);

      if (canon != NULL && strcmp (physname, canon) != 0)
	{
	  /* It may not mean a bug in GDB.  The compiler could also
	     compute DW_AT_linkage_name incorrectly.  But in such case
	     GDB would need to be bug-to-bug compatible.  */

	  complaint (_("Computed physname <%s> does not match demangled <%s> "
		       "(from linkage <%s>) - DIE at %s [in module %s]"),
		     physname, canon, mangled, sect_offset_str (die->sect_off),
		     objfile_name (objfile));

	  /* Prefer DW_AT_linkage_name (in the CANON form) - when it
	     is available here - over computed PHYSNAME.  It is safer
	     against both buggy GDB and buggy compilers.  */

	  retval = canon;
	}
      else
	{
	  retval = physname;
	  need_copy = 0;
	}
    }
  else
    retval = canon;

  if (need_copy)
    retval = obstack_strdup (&objfile->per_bfd->storage_obstack, retval);

  return retval;
}

/* Inspect DIE in CU for a namespace alias.  If one exists, record
   a new symbol for it.

   Returns 1 if a namespace alias was recorded, 0 otherwise.  */

static int
read_namespace_alias (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr;

  /* If the die does not have a name, this is not a namespace
     alias.  */
  attr = dwarf2_attr (die, DW_AT_name, cu);
  if (attr != NULL)
    {
      int num;
      struct die_info *d = die;
      struct dwarf2_cu *imported_cu = cu;

      /* If the compiler has nested DW_AT_imported_declaration DIEs,
	 keep inspecting DIEs until we hit the underlying import.  */
#define MAX_NESTED_IMPORTED_DECLARATIONS 100
      for (num = 0; num  < MAX_NESTED_IMPORTED_DECLARATIONS; ++num)
	{
	  attr = dwarf2_attr (d, DW_AT_import, cu);
	  if (attr == NULL)
	    break;

	  d = follow_die_ref (d, attr, &imported_cu);
	  if (d->tag != DW_TAG_imported_declaration)
	    break;
	}

      if (num == MAX_NESTED_IMPORTED_DECLARATIONS)
	{
	  complaint (_("DIE at %s has too many recursively imported "
		       "declarations"), sect_offset_str (d->sect_off));
	  return 0;
	}

      if (attr != NULL)
	{
	  struct type *type;
	  sect_offset sect_off = dwarf2_get_ref_die_offset (attr);

	  type = get_die_type_at_offset (sect_off, cu->per_cu);
	  if (type != NULL && TYPE_CODE (type) == TYPE_CODE_NAMESPACE)
	    {
	      /* This declaration is a global namespace alias.  Add
		 a symbol for it whose type is the aliased namespace.  */
	      new_symbol (die, type, cu);
	      return 1;
	    }
	}
    }

  return 0;
}

/* Return the using directives repository (global or local?) to use in the
   current context for CU.

   For Ada, imported declarations can materialize renamings, which *may* be
   global.  However it is impossible (for now?) in DWARF to distinguish
   "external" imported declarations and "static" ones.  As all imported
   declarations seem to be static in all other languages, make them all CU-wide
   global only in Ada.  */

static struct using_direct **
using_directives (struct dwarf2_cu *cu)
{
  if (cu->language == language_ada
      && cu->get_builder ()->outermost_context_p ())
    return cu->get_builder ()->get_global_using_directives ();
  else
    return cu->get_builder ()->get_local_using_directives ();
}

/* Read the import statement specified by the given die and record it.  */

static void
read_import_statement (struct die_info *die, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct attribute *import_attr;
  struct die_info *imported_die, *child_die;
  struct dwarf2_cu *imported_cu;
  const char *imported_name;
  const char *imported_name_prefix;
  const char *canonical_name;
  const char *import_alias;
  const char *imported_declaration = NULL;
  const char *import_prefix;
  std::vector<const char *> excludes;

  import_attr = dwarf2_attr (die, DW_AT_import, cu);
  if (import_attr == NULL)
    {
      complaint (_("Tag '%s' has no DW_AT_import"),
		 dwarf_tag_name (die->tag));
      return;
    }

  imported_cu = cu;
  imported_die = follow_die_ref_or_sig (die, import_attr, &imported_cu);
  imported_name = dwarf2_name (imported_die, imported_cu);
  if (imported_name == NULL)
    {
      /* GCC bug: https://bugzilla.redhat.com/show_bug.cgi?id=506524

        The import in the following code:
        namespace A
          {
            typedef int B;
          }

        int main ()
          {
            using A::B;
            B b;
            return b;
          }

        ...
         <2><51>: Abbrev Number: 3 (DW_TAG_imported_declaration)
            <52>   DW_AT_decl_file   : 1
            <53>   DW_AT_decl_line   : 6
            <54>   DW_AT_import      : <0x75>
         <2><58>: Abbrev Number: 4 (DW_TAG_typedef)
            <59>   DW_AT_name        : B
            <5b>   DW_AT_decl_file   : 1
            <5c>   DW_AT_decl_line   : 2
            <5d>   DW_AT_type        : <0x6e>
        ...
         <1><75>: Abbrev Number: 7 (DW_TAG_base_type)
            <76>   DW_AT_byte_size   : 4
            <77>   DW_AT_encoding    : 5        (signed)

        imports the wrong die ( 0x75 instead of 0x58 ).
        This case will be ignored until the gcc bug is fixed.  */
      return;
    }

  /* Figure out the local name after import.  */
  import_alias = dwarf2_name (die, cu);

  /* Figure out where the statement is being imported to.  */
  import_prefix = determine_prefix (die, cu);

  /* Figure out what the scope of the imported die is and prepend it
     to the name of the imported die.  */
  imported_name_prefix = determine_prefix (imported_die, imported_cu);

  if (imported_die->tag != DW_TAG_namespace
      && imported_die->tag != DW_TAG_module)
    {
      imported_declaration = imported_name;
      canonical_name = imported_name_prefix;
    }
  else if (strlen (imported_name_prefix) > 0)
    canonical_name = obconcat (&objfile->objfile_obstack,
			       imported_name_prefix,
			       (cu->language == language_d ? "." : "::"),
			       imported_name, (char *) NULL);
  else
    canonical_name = imported_name;

  if (die->tag == DW_TAG_imported_module && cu->language == language_fortran)
    for (child_die = die->child; child_die && child_die->tag;
	 child_die = sibling_die (child_die))
      {
	/* DWARF-4: A Fortran use statement with a “rename list” may be
	   represented by an imported module entry with an import attribute
	   referring to the module and owned entries corresponding to those
	   entities that are renamed as part of being imported.  */

	if (child_die->tag != DW_TAG_imported_declaration)
	  {
	    complaint (_("child DW_TAG_imported_declaration expected "
			 "- DIE at %s [in module %s]"),
		       sect_offset_str (child_die->sect_off),
		       objfile_name (objfile));
	    continue;
	  }

	import_attr = dwarf2_attr (child_die, DW_AT_import, cu);
	if (import_attr == NULL)
	  {
	    complaint (_("Tag '%s' has no DW_AT_import"),
		       dwarf_tag_name (child_die->tag));
	    continue;
	  }

	imported_cu = cu;
	imported_die = follow_die_ref_or_sig (child_die, import_attr,
					      &imported_cu);
	imported_name = dwarf2_name (imported_die, imported_cu);
	if (imported_name == NULL)
	  {
	    complaint (_("child DW_TAG_imported_declaration has unknown "
			 "imported name - DIE at %s [in module %s]"),
		       sect_offset_str (child_die->sect_off),
		       objfile_name (objfile));
	    continue;
	  }

	excludes.push_back (imported_name);

	process_die (child_die, cu);
      }

  add_using_directive (using_directives (cu),
		       import_prefix,
		       canonical_name,
		       import_alias,
		       imported_declaration,
		       excludes,
		       0,
		       &objfile->objfile_obstack);
}

/* ICC<14 does not output the required DW_AT_declaration on incomplete
   types, but gives them a size of zero.  Starting with version 14,
   ICC is compatible with GCC.  */

static bool
producer_is_icc_lt_14 (struct dwarf2_cu *cu)
{
  if (!cu->checked_producer)
    check_producer (cu);

  return cu->producer_is_icc_lt_14;
}

/* ICC generates a DW_AT_type for C void functions.  This was observed on
   ICC 14.0.5.212, and appears to be against the DWARF spec (V5 3.3.2)
   which says that void functions should not have a DW_AT_type.  */

static bool
producer_is_icc (struct dwarf2_cu *cu)
{
  if (!cu->checked_producer)
    check_producer (cu);

  return cu->producer_is_icc;
}

/* Check for possibly missing DW_AT_comp_dir with relative .debug_line
   directory paths.  GCC SVN r127613 (new option -fdebug-prefix-map) fixed
   this, it was first present in GCC release 4.3.0.  */

static bool
producer_is_gcc_lt_4_3 (struct dwarf2_cu *cu)
{
  if (!cu->checked_producer)
    check_producer (cu);

  return cu->producer_is_gcc_lt_4_3;
}

static file_and_directory
find_file_and_directory (struct die_info *die, struct dwarf2_cu *cu)
{
  file_and_directory res;

  /* Find the filename.  Do not use dwarf2_name here, since the filename
     is not a source language identifier.  */
  res.name = dwarf2_string_attr (die, DW_AT_name, cu);
  res.comp_dir = dwarf2_string_attr (die, DW_AT_comp_dir, cu);

  if (res.comp_dir == NULL
      && producer_is_gcc_lt_4_3 (cu) && res.name != NULL
      && IS_ABSOLUTE_PATH (res.name))
    {
      res.comp_dir_storage = ldirname (res.name);
      if (!res.comp_dir_storage.empty ())
	res.comp_dir = res.comp_dir_storage.c_str ();
    }
  if (res.comp_dir != NULL)
    {
      /* Irix 6.2 native cc prepends <machine>.: to the compilation
	 directory, get rid of it.  */
      const char *cp = strchr (res.comp_dir, ':');

      if (cp && cp != res.comp_dir && cp[-1] == '.' && cp[1] == '/')
	res.comp_dir = cp + 1;
    }

  if (res.name == NULL)
    res.name = "<unknown>";

  return res;
}

/* Handle DW_AT_stmt_list for a compilation unit.
   DIE is the DW_TAG_compile_unit die for CU.
   COMP_DIR is the compilation directory.  LOWPC is passed to
   dwarf_decode_lines.  See dwarf_decode_lines comments about it.  */

static void
handle_DW_AT_stmt_list (struct die_info *die, struct dwarf2_cu *cu,
			const char *comp_dir, CORE_ADDR lowpc) /* ARI: editCase function */
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct attribute *attr;
  struct line_header line_header_local;
  hashval_t line_header_local_hash;
  void **slot;
  int decode_mapping;

  gdb_assert (! cu->per_cu->is_debug_types);

  attr = dwarf2_attr (die, DW_AT_stmt_list, cu);
  if (attr == NULL)
    return;

  sect_offset line_offset = (sect_offset) DW_UNSND (attr);

  /* The line header hash table is only created if needed (it exists to
     prevent redundant reading of the line table for partial_units).
     If we're given a partial_unit, we'll need it.  If we're given a
     compile_unit, then use the line header hash table if it's already
     created, but don't create one just yet.  */

  if (dwarf2_per_objfile->line_header_hash == NULL
      && die->tag == DW_TAG_partial_unit)
    {
      dwarf2_per_objfile->line_header_hash
	= htab_create_alloc_ex (127, line_header_hash_voidp,
				line_header_eq_voidp,
				free_line_header_voidp,
				&objfile->objfile_obstack,
				hashtab_obstack_allocate,
				dummy_obstack_deallocate);
    }

  line_header_local.sect_off = line_offset;
  line_header_local.offset_in_dwz = cu->per_cu->is_dwz;
  line_header_local_hash = line_header_hash (&line_header_local);
  if (dwarf2_per_objfile->line_header_hash != NULL)
    {
      slot = htab_find_slot_with_hash (dwarf2_per_objfile->line_header_hash,
				       &line_header_local,
				       line_header_local_hash, NO_INSERT);

      /* For DW_TAG_compile_unit we need info like symtab::linetable which
	 is not present in *SLOT (since if there is something in *SLOT then
	 it will be for a partial_unit).  */
      if (die->tag == DW_TAG_partial_unit && slot != NULL)
	{
	  gdb_assert (*slot != NULL);
	  cu->line_header = (struct line_header *) *slot;
	  return;
	}
    }

  /* dwarf_decode_line_header does not yet provide sufficient information.
     We always have to call also dwarf_decode_lines for it.  */
  line_header_up lh = dwarf_decode_line_header (line_offset, cu);
  if (lh == NULL)
    return;

  cu->line_header = lh.release ();
  cu->line_header_die_owner = die;

  if (dwarf2_per_objfile->line_header_hash == NULL)
    slot = NULL;
  else
    {
      slot = htab_find_slot_with_hash (dwarf2_per_objfile->line_header_hash,
				       &line_header_local,
				       line_header_local_hash, INSERT);
      gdb_assert (slot != NULL);
    }
  if (slot != NULL && *slot == NULL)
    {
      /* This newly decoded line number information unit will be owned
	 by line_header_hash hash table.  */
      *slot = cu->line_header;
      cu->line_header_die_owner = NULL;
    }
  else
    {
      /* We cannot free any current entry in (*slot) as that struct line_header
         may be already used by multiple CUs.  Create only temporary decoded
	 line_header for this CU - it may happen at most once for each line
	 number information unit.  And if we're not using line_header_hash
	 then this is what we want as well.  */
      gdb_assert (die->tag != DW_TAG_partial_unit);
    }
  decode_mapping = (die->tag != DW_TAG_partial_unit);
  dwarf_decode_lines (cu->line_header, comp_dir, cu, NULL, lowpc,
		      decode_mapping);

}

/* Process DW_TAG_compile_unit or DW_TAG_partial_unit.  */

static void
read_file_scope (struct die_info *die, struct dwarf2_cu *cu)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  CORE_ADDR lowpc = ((CORE_ADDR) -1);
  CORE_ADDR highpc = ((CORE_ADDR) 0);
  struct attribute *attr;
  struct die_info *child_die;
  CORE_ADDR baseaddr;

  prepare_one_comp_unit (cu, die, cu->language);
  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  get_scope_pc_bounds (die, &lowpc, &highpc, cu);

  /* If we didn't find a lowpc, set it to highpc to avoid complaints
     from finish_block.  */
  if (lowpc == ((CORE_ADDR) -1))
    lowpc = highpc;
  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);

  file_and_directory fnd = find_file_and_directory (die, cu);

  /* The XLCL doesn't generate DW_LANG_OpenCL because this attribute is not
     standardised yet.  As a workaround for the language detection we fall
     back to the DW_AT_producer string.  */
  if (cu->producer && strstr (cu->producer, "IBM XL C for OpenCL") != NULL)
    cu->language = language_opencl;

  /* Similar hack for Go.  */
  if (cu->producer && strstr (cu->producer, "GNU Go ") != NULL)
    set_cu_language (DW_LANG_Go, cu);

  cu->start_symtab (fnd.name, fnd.comp_dir, lowpc);

  /* Decode line number information if present.  We do this before
     processing child DIEs, so that the line header table is available
     for DW_AT_decl_file.  */
  handle_DW_AT_stmt_list (die, cu, fnd.comp_dir, lowpc);

  /* Process all dies in compilation unit.  */
  if (die->child != NULL)
    {
      child_die = die->child;
      while (child_die && child_die->tag)
	{
	  process_die (child_die, cu);
	  child_die = sibling_die (child_die);
	}
    }

  /* Decode macro information, if present.  Dwarf 2 macro information
     refers to information in the line number info statement program
     header, so we can only read it if we've read the header
     successfully.  */
  attr = dwarf2_attr (die, DW_AT_macros, cu);
  if (attr == NULL)
    attr = dwarf2_attr (die, DW_AT_GNU_macros, cu);
  if (attr && cu->line_header)
    {
      if (dwarf2_attr (die, DW_AT_macro_info, cu))
	complaint (_("CU refers to both DW_AT_macros and DW_AT_macro_info"));

      dwarf_decode_macros (cu, DW_UNSND (attr), 1);
    }
  else
    {
      attr = dwarf2_attr (die, DW_AT_macro_info, cu);
      if (attr && cu->line_header)
	{
	  unsigned int macro_offset = DW_UNSND (attr);

	  dwarf_decode_macros (cu, macro_offset, 0);
	}
    }
}

void
dwarf2_cu::setup_type_unit_groups (struct die_info *die)
{
  struct type_unit_group *tu_group;
  int first_time;
  struct attribute *attr;
  unsigned int i;
  struct signatured_type *sig_type;

  gdb_assert (per_cu->is_debug_types);
  sig_type = (struct signatured_type *) per_cu;

  attr = dwarf2_attr (die, DW_AT_stmt_list, this);

  /* If we're using .gdb_index (includes -readnow) then
     per_cu->type_unit_group may not have been set up yet.  */
  if (sig_type->type_unit_group == NULL)
    sig_type->type_unit_group = get_type_unit_group (this, attr);
  tu_group = sig_type->type_unit_group;

  /* If we've already processed this stmt_list there's no real need to
     do it again, we could fake it and just recreate the part we need
     (file name,index -> symtab mapping).  If data shows this optimization
     is useful we can do it then.  */
  first_time = tu_group->compunit_symtab == NULL;

  /* We have to handle the case of both a missing DW_AT_stmt_list or bad
     debug info.  */
  line_header_up lh;
  if (attr != NULL)
    {
      sect_offset line_offset = (sect_offset) DW_UNSND (attr);
      lh = dwarf_decode_line_header (line_offset, this);
    }
  if (lh == NULL)
    {
      if (first_time)
	start_symtab ("", NULL, 0);
      else
	{
	  gdb_assert (tu_group->symtabs == NULL);
	  gdb_assert (m_builder == nullptr);
	  struct compunit_symtab *cust = tu_group->compunit_symtab;
	  m_builder.reset (new struct buildsym_compunit
			   (COMPUNIT_OBJFILE (cust), "",
			    COMPUNIT_DIRNAME (cust),
			    compunit_language (cust),
			    0, cust));
	}
      return;
    }

  line_header = lh.release ();
  line_header_die_owner = die;

  if (first_time)
    {
      struct compunit_symtab *cust = start_symtab ("", NULL, 0);

      /* Note: We don't assign tu_group->compunit_symtab yet because we're
	 still initializing it, and our caller (a few levels up)
	 process_full_type_unit still needs to know if this is the first
	 time.  */

      tu_group->num_symtabs = line_header->file_names_size ();
      tu_group->symtabs = XNEWVEC (struct symtab *,
				   line_header->file_names_size ());

      auto &file_names = line_header->file_names ();
      for (i = 0; i < file_names.size (); ++i)
	{
	  file_entry &fe = file_names[i];
	  dwarf2_start_subfile (this, fe.name,
				fe.include_dir (line_header));
	  buildsym_compunit *b = get_builder ();
	  if (b->get_current_subfile ()->symtab == NULL)
	    {
	      /* NOTE: start_subfile will recognize when it's been
		 passed a file it has already seen.  So we can't
		 assume there's a simple mapping from
		 cu->line_header->file_names to subfiles, plus
		 cu->line_header->file_names may contain dups.  */
	      b->get_current_subfile ()->symtab
		= allocate_symtab (cust, b->get_current_subfile ()->name);
	    }

	  fe.symtab = b->get_current_subfile ()->symtab;
	  tu_group->symtabs[i] = fe.symtab;
	}
    }
  else
    {
      gdb_assert (m_builder == nullptr);
      struct compunit_symtab *cust = tu_group->compunit_symtab;
      m_builder.reset (new struct buildsym_compunit
		       (COMPUNIT_OBJFILE (cust), "",
			COMPUNIT_DIRNAME (cust),
			compunit_language (cust),
			0, cust));

      auto &file_names = line_header->file_names ();
      for (i = 0; i < file_names.size (); ++i)
	{
	  file_entry &fe = file_names[i];
	  fe.symtab = tu_group->symtabs[i];
	}
    }

  /* The main symtab is allocated last.  Type units don't have DW_AT_name
     so they don't have a "real" (so to speak) symtab anyway.
     There is later code that will assign the main symtab to all symbols
     that don't have one.  We need to handle the case of a symbol with a
     missing symtab (DW_AT_decl_file) anyway.  */
}

/* Process DW_TAG_type_unit.
   For TUs we want to skip the first top level sibling if it's not the
   actual type being defined by this TU.  In this case the first top
   level sibling is there to provide context only.  */

static void
read_type_unit_scope (struct die_info *die, struct dwarf2_cu *cu)
{
  struct die_info *child_die;

  prepare_one_comp_unit (cu, die, language_minimal);

  /* Initialize (or reinitialize) the machinery for building symtabs.
     We do this before processing child DIEs, so that the line header table
     is available for DW_AT_decl_file.  */
  cu->setup_type_unit_groups (die);

  if (die->child != NULL)
    {
      child_die = die->child;
      while (child_die && child_die->tag)
	{
	  process_die (child_die, cu);
	  child_die = sibling_die (child_die);
	}
    }
}

/* DWO/DWP files.

   http://gcc.gnu.org/wiki/DebugFission
   http://gcc.gnu.org/wiki/DebugFissionDWP

   To simplify handling of both DWO files ("object" files with the DWARF info)
   and DWP files (a file with the DWOs packaged up into one file), we treat
   DWP files as having a collection of virtual DWO files.  */

static hashval_t
hash_dwo_file (const void *item)
{
  const struct dwo_file *dwo_file = (const struct dwo_file *) item;
  hashval_t hash;

  hash = htab_hash_string (dwo_file->dwo_name);
  if (dwo_file->comp_dir != NULL)
    hash += htab_hash_string (dwo_file->comp_dir);
  return hash;
}

static int
eq_dwo_file (const void *item_lhs, const void *item_rhs)
{
  const struct dwo_file *lhs = (const struct dwo_file *) item_lhs;
  const struct dwo_file *rhs = (const struct dwo_file *) item_rhs;

  if (strcmp (lhs->dwo_name, rhs->dwo_name) != 0)
    return 0;
  if (lhs->comp_dir == NULL || rhs->comp_dir == NULL)
    return lhs->comp_dir == rhs->comp_dir;
  return strcmp (lhs->comp_dir, rhs->comp_dir) == 0;
}

/* Allocate a hash table for DWO files.  */

static htab_up
allocate_dwo_file_hash_table (struct objfile *objfile)
{
  auto delete_dwo_file = [] (void *item)
    {
      struct dwo_file *dwo_file = (struct dwo_file *) item;

      delete dwo_file;
    };

  return htab_up (htab_create_alloc_ex (41,
					hash_dwo_file,
					eq_dwo_file,
					delete_dwo_file,
					&objfile->objfile_obstack,
					hashtab_obstack_allocate,
					dummy_obstack_deallocate));
}

/* Lookup DWO file DWO_NAME.  */

static void **
lookup_dwo_file_slot (struct dwarf2_per_objfile *dwarf2_per_objfile,
		      const char *dwo_name,
		      const char *comp_dir)
{
  struct dwo_file find_entry;
  void **slot;

  if (dwarf2_per_objfile->dwo_files == NULL)
    dwarf2_per_objfile->dwo_files
      = allocate_dwo_file_hash_table (dwarf2_per_objfile->objfile);

  find_entry.dwo_name = dwo_name;
  find_entry.comp_dir = comp_dir;
  slot = htab_find_slot (dwarf2_per_objfile->dwo_files.get (), &find_entry,
			 INSERT);

  return slot;
}

static hashval_t
hash_dwo_unit (const void *item)
{
  const struct dwo_unit *dwo_unit = (const struct dwo_unit *) item;

  /* This drops the top 32 bits of the id, but is ok for a hash.  */
  return dwo_unit->signature;
}

static int
eq_dwo_unit (const void *item_lhs, const void *item_rhs)
{
  const struct dwo_unit *lhs = (const struct dwo_unit *) item_lhs;
  const struct dwo_unit *rhs = (const struct dwo_unit *) item_rhs;

  /* The signature is assumed to be unique within the DWO file.
     So while object file CU dwo_id's always have the value zero,
     that's OK, assuming each object file DWO file has only one CU,
     and that's the rule for now.  */
  return lhs->signature == rhs->signature;
}

/* Allocate a hash table for DWO CUs,TUs.
   There is one of these tables for each of CUs,TUs for each DWO file.  */

static htab_t
allocate_dwo_unit_table (struct objfile *objfile)
{
  /* Start out with a pretty small number.
     Generally DWO files contain only one CU and maybe some TUs.  */
  return htab_create_alloc_ex (3,
			       hash_dwo_unit,
			       eq_dwo_unit,
			       NULL,
			       &objfile->objfile_obstack,
			       hashtab_obstack_allocate,
			       dummy_obstack_deallocate);
}

/* Structure used to pass data to create_dwo_debug_info_hash_table_reader.  */

struct create_dwo_cu_data
{
  struct dwo_file *dwo_file;
  struct dwo_unit dwo_unit;
};

/* die_reader_func for create_dwo_cu.  */

static void
create_dwo_cu_reader (const struct die_reader_specs *reader,
		      const gdb_byte *info_ptr,
		      struct die_info *comp_unit_die,
		      int has_children,
		      void *datap)
{
  struct dwarf2_cu *cu = reader->cu;
  sect_offset sect_off = cu->per_cu->sect_off;
  struct dwarf2_section_info *section = cu->per_cu->section;
  struct create_dwo_cu_data *data = (struct create_dwo_cu_data *) datap;
  struct dwo_file *dwo_file = data->dwo_file;
  struct dwo_unit *dwo_unit = &data->dwo_unit;

  gdb::optional<ULONGEST> signature = lookup_dwo_id (cu, comp_unit_die);
  if (!signature.has_value ())
    {
      complaint (_("Dwarf Error: debug entry at offset %s is missing"
		   " its dwo_id [in module %s]"),
		 sect_offset_str (sect_off), dwo_file->dwo_name);
      return;
    }

  dwo_unit->dwo_file = dwo_file;
  dwo_unit->signature = *signature;
  dwo_unit->section = section;
  dwo_unit->sect_off = sect_off;
  dwo_unit->length = cu->per_cu->length;

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "  offset %s, dwo_id %s\n",
			sect_offset_str (sect_off),
			hex_string (dwo_unit->signature));
}

/* Create the dwo_units for the CUs in a DWO_FILE.
   Note: This function processes DWO files only, not DWP files.  */

static void
create_cus_hash_table (struct dwarf2_per_objfile *dwarf2_per_objfile,
		       dwarf2_cu *cu, struct dwo_file &dwo_file,
		       dwarf2_section_info &section, htab_t &cus_htab)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  const gdb_byte *info_ptr, *end_ptr;

  dwarf2_read_section (objfile, &section);
  info_ptr = section.buffer;

  if (info_ptr == NULL)
    return;

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Reading %s for %s:\n",
			  get_section_name (&section),
			  get_section_file_name (&section));
    }

  end_ptr = info_ptr + section.size;
  while (info_ptr < end_ptr)
    {
      struct dwarf2_per_cu_data per_cu;
      struct create_dwo_cu_data create_dwo_cu_data;
      struct dwo_unit *dwo_unit;
      void **slot;
      sect_offset sect_off = (sect_offset) (info_ptr - section.buffer);

      memset (&create_dwo_cu_data.dwo_unit, 0,
	      sizeof (create_dwo_cu_data.dwo_unit));
      memset (&per_cu, 0, sizeof (per_cu));
      per_cu.dwarf2_per_objfile = dwarf2_per_objfile;
      per_cu.is_debug_types = 0;
      per_cu.sect_off = sect_offset (info_ptr - section.buffer);
      per_cu.section = &section;
      create_dwo_cu_data.dwo_file = &dwo_file;

      init_cutu_and_read_dies_no_follow (
	  &per_cu, cu, &dwo_file, create_dwo_cu_reader, &create_dwo_cu_data);
      info_ptr += per_cu.length;

      // If the unit could not be parsed, skip it.
      if (create_dwo_cu_data.dwo_unit.dwo_file == NULL)
	continue;

      if (cus_htab == NULL)
	cus_htab = allocate_dwo_unit_table (objfile);

      dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
      *dwo_unit = create_dwo_cu_data.dwo_unit;
      slot = htab_find_slot (cus_htab, dwo_unit, INSERT);
      gdb_assert (slot != NULL);
      if (*slot != NULL)
	{
	  const struct dwo_unit *dup_cu = (const struct dwo_unit *)*slot;
	  sect_offset dup_sect_off = dup_cu->sect_off;

	  complaint (_("debug cu entry at offset %s is duplicate to"
		       " the entry at offset %s, signature %s"),
		     sect_offset_str (sect_off), sect_offset_str (dup_sect_off),
		     hex_string (dwo_unit->signature));
	}
      *slot = (void *)dwo_unit;
    }
}

/* DWP file .debug_{cu,tu}_index section format:
   [ref: http://gcc.gnu.org/wiki/DebugFissionDWP]

   DWP Version 1:

   Both index sections have the same format, and serve to map a 64-bit
   signature to a set of section numbers.  Each section begins with a header,
   followed by a hash table of 64-bit signatures, a parallel table of 32-bit
   indexes, and a pool of 32-bit section numbers.  The index sections will be
   aligned at 8-byte boundaries in the file.

   The index section header consists of:

    V, 32 bit version number
    -, 32 bits unused
    N, 32 bit number of compilation units or type units in the index
    M, 32 bit number of slots in the hash table

   Numbers are recorded using the byte order of the application binary.

   The hash table begins at offset 16 in the section, and consists of an array
   of M 64-bit slots.  Each slot contains a 64-bit signature (using the byte
   order of the application binary).  Unused slots in the hash table are 0.
   (We rely on the extreme unlikeliness of a signature being exactly 0.)

   The parallel table begins immediately after the hash table
   (at offset 16 + 8 * M from the beginning of the section), and consists of an
   array of 32-bit indexes (using the byte order of the application binary),
   corresponding 1-1 with slots in the hash table.  Each entry in the parallel
   table contains a 32-bit index into the pool of section numbers.  For unused
   hash table slots, the corresponding entry in the parallel table will be 0.

   The pool of section numbers begins immediately following the hash table
   (at offset 16 + 12 * M from the beginning of the section).  The pool of
   section numbers consists of an array of 32-bit words (using the byte order
   of the application binary).  Each item in the array is indexed starting
   from 0.  The hash table entry provides the index of the first section
   number in the set.  Additional section numbers in the set follow, and the
   set is terminated by a 0 entry (section number 0 is not used in ELF).

   In each set of section numbers, the .debug_info.dwo or .debug_types.dwo
   section must be the first entry in the set, and the .debug_abbrev.dwo must
   be the second entry. Other members of the set may follow in any order.

   ---

   DWP Versions 2 and 5:

   DWP Versions 2 and 5 combine all the .debug_info, etc. sections into one,
   and the entries in the index tables are now offsets into these sections.
   CU offsets begin at 0.  TU offsets begin at the size of the .debug_info
   section.

   Index Section Contents:
    Header
    Hash Table of Signatures   dwp_hash_table.hash_table
    Parallel Table of Indices  dwp_hash_table.unit_table
    Table of Section Offsets   dwp_hash_table.v2|v5.{section_ids,offsets}
    Table of Section Sizes     dwp_hash_table.v2|v5.sizes

   The index section header consists of:

    V, 32 bit version number
    L, 32 bit number of columns in the table of section offsets
    N, 32 bit number of compilation units or type units in the index
    M, 32 bit number of slots in the hash table

   Numbers are recorded using the byte order of the application binary.

   The hash table has the same format as version 1.
   The parallel table of indices has the same format as version 1,
   except that the entries are origin-1 indices into the table of sections
   offsets and the table of section sizes.

   The table of offsets begins immediately following the parallel table
   (at offset 16 + 12 * M from the beginning of the section).  The table is
   a two-dimensional array of 32-bit words (using the byte order of the
   application binary), with L columns and N+1 rows, in row-major order.
   Each row in the array is indexed starting from 0.  The first row provides
   a key to the remaining rows: each column in this row provides an identifier
   for a debug section, and the offsets in the same column of subsequent rows
   refer to that section.  The section identifiers for Version 2 are:

    DW_SECT_INFO         1  .debug_info.dwo
    DW_SECT_TYPES        2  .debug_types.dwo
    DW_SECT_ABBREV       3  .debug_abbrev.dwo
    DW_SECT_LINE         4  .debug_line.dwo
    DW_SECT_LOC          5  .debug_loc.dwo
    DW_SECT_STR_OFFSETS  6  .debug_str_offsets.dwo
    DW_SECT_MACINFO      7  .debug_macinfo.dwo
    DW_SECT_MACRO        8  .debug_macro.dwo

   The section identifiers for Version 5 are:

    DW_SECT_INFO_V5         1  .debug_info.dwo
    DW_SECT_RESERVED_V5     2  --
    DW_SECT_ABBREV_V5       3  .debug_abbrev.dwo
    DW_SECT_LINE_V5         4  .debug_line.dwo
    DW_SECT_LOCLISTS_V5     5  .debug_loclists.dwo
    DW_SECT_STR_OFFSETS_V5  6  .debug_str_offsets.dwo
    DW_SECT_MACRO_V5        7  .debug_macro.dwo
    DW_SECT_RNGLISTS_V5     8  .debug_rnglists.dwo

   The offsets provided by the CU and TU index sections are the base offsets
   for the contributions made by each CU or TU to the corresponding section
   in the package file.  Each CU and TU header contains an abbrev_offset
   field, used to find the abbreviations table for that CU or TU within the
   contribution to the .debug_abbrev.dwo section for that CU or TU, and should
   be interpreted as relative to the base offset given in the index section.
   Likewise, offsets into .debug_line.dwo from DW_AT_stmt_list attributes
   should be interpreted as relative to the base offset for .debug_line.dwo,
   and offsets into other debug sections obtained from DWARF attributes should
   also be interpreted as relative to the corresponding base offset.

   The table of sizes begins immediately following the table of offsets.
   Like the table of offsets, it is a two-dimensional array of 32-bit words,
   with L columns and N rows, in row-major order.  Each row in the array is
   indexed starting from 1 (row 0 is shared by the two tables).

   ---

   Hash table lookup is handled the same in version 1 and 2:

   We assume that N and M will not exceed 2^32 - 1.
   The size of the hash table, M, must be 2^k such that 2^k > 3*N/2.

   Given a 64-bit compilation unit signature or a type signature S, an entry
   in the hash table is located as follows:

   1) Calculate a primary hash H = S & MASK(k), where MASK(k) is a mask with
      the low-order k bits all set to 1.

   2) Calculate a secondary hash H' = (((S >> 32) & MASK(k)) | 1).

   3) If the hash table entry at index H matches the signature, use that
      entry.  If the hash table entry at index H is unused (all zeroes),
      terminate the search: the signature is not present in the table.

   4) Let H = (H + H') modulo M. Repeat at Step 3.

   Because M > N and H' and M are relatively prime, the search is guaranteed
   to stop at an unused slot or find the match.  */

/* Create a hash table to map DWO IDs to their CU/TU entry in
   .debug_{info,types}.dwo in DWP_FILE.
   Returns NULL if there isn't one.
   Note: This function processes DWP files only, not DWO files.  */

static struct dwp_hash_table *
create_dwp_hash_table (struct dwarf2_per_objfile *dwarf2_per_objfile,
		       struct dwp_file *dwp_file, int is_debug_types)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  bfd *dbfd = dwp_file->dbfd.get ();
  const gdb_byte *index_ptr, *index_end;
  struct dwarf2_section_info *index;
  uint32_t version, nr_columns, nr_units, nr_slots;
  struct dwp_hash_table *htab;

  if (is_debug_types)
    index = &dwp_file->sections.tu_index;
  else
    index = &dwp_file->sections.cu_index;

  if (dwarf2_section_empty_p (index))
    return NULL;
  dwarf2_read_section (objfile, index);

  index_ptr = index->buffer;
  index_end = index_ptr + index->size;

  /* For Version 5, the version is really 2 bytes of data & 2 bytes of
     padding. For now it's safe to just read 4 bytes (particularly as it's
     difficult to tell if you're dealing with Version 5 before you've read the
     version). */
  version = read_4_bytes (dbfd, index_ptr);
  index_ptr += 4;
  if ((version == 2) || (version == 5))
      nr_columns = read_4_bytes (dbfd, index_ptr);
  else
    nr_columns = 0;
  index_ptr += 4;
  nr_units = read_4_bytes (dbfd, index_ptr);
  index_ptr += 4;
  nr_slots = read_4_bytes (dbfd, index_ptr);
  index_ptr += 4;

  if (version != 1 && version != 2 && version != 5)
    {
      error (_("Dwarf Error: unsupported DWP file version (%s)"
	       " [in module %s]"),
	     pulongest (version), dwp_file->name);
    }
  if (nr_slots != (nr_slots & -nr_slots))
    {
      error (_("Dwarf Error: number of slots in DWP hash table (%s)"
	       " is not power of 2 [in module %s]"),
	     pulongest (nr_slots), dwp_file->name);
    }

  htab = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwp_hash_table);
  htab->version = version;
  htab->nr_columns = nr_columns;
  htab->nr_units = nr_units;
  htab->nr_slots = nr_slots;
  htab->hash_table = index_ptr;
  htab->unit_table = htab->hash_table + sizeof (uint64_t) * nr_slots;

  /* Exit early if the table is empty.  */
  if (nr_slots == 0 || nr_units == 0
      || (version == 2 && nr_columns == 0)
      || (version == 5 && nr_columns == 0))
    {
      /* All must be zero.  */
      if (nr_slots != 0 || nr_units != 0
	  || (version == 2 && nr_columns != 0)
          || (version == 5 && nr_columns != 0))
	{
	  complaint (_("Empty DWP but nr_slots,nr_units,nr_columns not"
		       " all zero [in modules %s]"),
		     dwp_file->name);
	}
      return htab;
    }

  if (version == 1)
    {
      htab->section_pool.v1.indices =
	htab->unit_table + sizeof (uint32_t) * nr_slots;
      /* It's harder to decide whether the section is too small in v1.
	 V1 is deprecated anyway so we punt.  */
    }
  else if (version == 2)
    {
      const gdb_byte *ids_ptr = htab->unit_table + sizeof (uint32_t) * nr_slots;
      int *ids = htab->section_pool.v2.section_ids;
      size_t sizeof_ids = sizeof (htab->section_pool.v2.section_ids);
      /* Reverse map for error checking.  */
      int ids_seen[DW_SECT_MAX + 1];
      int i;

      if (nr_columns < 2)
	{
	  error (_("Dwarf Error: bad DWP hash table, too few columns"
		   " in section table [in module %s]"),
		 dwp_file->name);
	}
      if (nr_columns > MAX_NR_V2_DWO_SECTIONS)
	{
	  error (_("Dwarf Error: bad DWP hash table, too many columns"
		   " in section table [in module %s]"),
		 dwp_file->name);
	}
      memset (ids, 255, sizeof_ids);
      memset (ids_seen, 255, sizeof (ids_seen));
      for (i = 0; i < nr_columns; ++i)
	{
	  int id = read_4_bytes (dbfd, ids_ptr + i * sizeof (uint32_t));

	  if (id < DW_SECT_MIN || id > DW_SECT_MAX)
	    {
	      error (_("Dwarf Error: bad DWP hash table, bad section id %d"
		       " in section table [in module %s]"),
		     id, dwp_file->name);
	    }
	  if (ids_seen[id] != -1)
	    {
	      error (_("Dwarf Error: bad DWP hash table, duplicate section"
		       " id %d in section table [in module %s]"),
		     id, dwp_file->name);
	    }
	  ids_seen[id] = i;
	  ids[i] = id;
	}
      /* Must have exactly one info or types section.  */
      if (((ids_seen[DW_SECT_INFO] != -1)
	   + (ids_seen[DW_SECT_TYPES] != -1))
	  != 1)
	{
	  error (_("Dwarf Error: bad DWP hash table, missing/duplicate"
		   " DWO info/types section [in module %s]"),
		 dwp_file->name);
	}
      /* Must have an abbrev section.  */
      if (ids_seen[DW_SECT_ABBREV] == -1)
	{
	  error (_("Dwarf Error: bad DWP hash table, missing DWO abbrev"
		   " section [in module %s]"),
		 dwp_file->name);
	}
      htab->section_pool.v2.offsets = ids_ptr + sizeof (uint32_t) * nr_columns;
      htab->section_pool.v2.sizes =
	htab->section_pool.v2.offsets + (sizeof (uint32_t)
					 * nr_units * nr_columns);
      if ((htab->section_pool.v2.sizes + (sizeof (uint32_t)
					  * nr_units * nr_columns))
	  > index_end)
	{
	  error (_("Dwarf Error: DWP index section is corrupt (too small)"
		   " [in module %s]"),
		 dwp_file->name);
	}
    }
  else // version == 5
    {
      const gdb_byte *ids_ptr = htab->unit_table + sizeof (uint32_t) * nr_slots;

      int *ids = htab->section_pool.v5.section_ids;
      size_t sizeof_ids = sizeof (htab->section_pool.v5.section_ids);
      /* Reverse map for error checking.  */
      int ids_seen[DW_SECT_MAX + 1];
      int i;

      if (nr_columns < 2)
        {
          error (_("Dwarf Error: bad DWP hash table, too few columns"
                   " in section table [in module %s]"),
                 dwp_file->name);
        }
      if (nr_columns > MAX_NR_V5_DWO_SECTIONS)
        {
          error (_("Dwarf Error: bad DWP hash table, too many columns"
                   " in section table [in module %s]"),
                 dwp_file->name);
        }
      memset (ids, 255, sizeof_ids);
      memset (ids_seen, 255, sizeof (ids_seen));
      for (i = 0; i < nr_columns; ++i)
        {
          int id = read_4_bytes (dbfd, ids_ptr + i * sizeof (uint32_t));

          if (id < DW_SECT_MIN || id > DW_SECT_MAX_V5)
            {
              error (_("Dwarf Error: bad DWP hash table, bad section id %d"
                       " in section table [in module %s]"),
                     id, dwp_file->name);
            }
          if (ids_seen[id] != -1)
            {
              error (_("Dwarf Error: bad DWP hash table, duplicate section"
                       " id %d in section table [in module %s]"),
                     id, dwp_file->name);
            }
          ids_seen[id] = i;
          ids[i] = id;
        }
      /* Must have an info section.  */
      if (ids_seen[DW_SECT_INFO_V5] == -1)
        {
          error (_("Dwarf Error: bad DWP hash table, missing/duplicate"
                   " DWO info section [in module %s]"),
                 dwp_file->name);
        }
      /* Must have an abbrev section.  */
      if (ids_seen[DW_SECT_ABBREV_V5] == -1)
        {
          error (_("Dwarf Error: bad DWP hash table, missing DWO abbrev"
                   " section [in module %s]"),
                 dwp_file->name);
        }
      htab->section_pool.v5.offsets = ids_ptr + sizeof (uint32_t) * nr_columns;
      htab->section_pool.v5.sizes =
          htab->section_pool.v5.offsets + (sizeof (uint32_t)
                                           * nr_units * nr_columns);
      if ((htab->section_pool.v5.sizes + (sizeof (uint32_t)
                                          * nr_units * nr_columns))
          > index_end)
        {
          error (_("Dwarf Error: DWP index section is corrupt (too small)"
                   " [in module %s]"),
                 dwp_file->name);
        }
    }

  return htab;
}

/* Update SECTIONS with the data from SECTP.

   This function is like the other "locate" section routines that are
   passed to bfd_map_over_sections, but in this context the sections to
   read comes from the DWP V1 hash table, not the full ELF section table.

   The result is non-zero for success, or zero if an error was found.  */

static int
locate_v1_virtual_dwo_sections (asection *sectp,
				struct virtual_v1_dwo_sections *sections)
{
  const struct dwop_section_names *names = &dwop_section_names;

  if (section_is_p (sectp->name, &names->abbrev_dwo))
    {
      /* There can be only one.  */
      if (sections->abbrev.s.section != NULL)
	return 0;
      sections->abbrev.s.section = sectp;
      sections->abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->info_dwo)
	   || section_is_p (sectp->name, &names->types_dwo))
    {
      /* There can be only one.  */
      if (sections->info_or_types.s.section != NULL)
	return 0;
      sections->info_or_types.s.section = sectp;
      sections->info_or_types.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->line_dwo))
    {
      /* There can be only one.  */
      if (sections->line.s.section != NULL)
	return 0;
      sections->line.s.section = sectp;
      sections->line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->loc_dwo))
    {
      /* There can be only one.  */
      if (sections->loc.s.section != NULL)
	return 0;
      sections->loc.s.section = sectp;
      sections->loc.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macinfo_dwo))
    {
      /* There can be only one.  */
      if (sections->macinfo.s.section != NULL)
	return 0;
      sections->macinfo.s.section = sectp;
      sections->macinfo.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macro_dwo))
    {
      /* There can be only one.  */
      if (sections->macro.s.section != NULL)
	return 0;
      sections->macro.s.section = sectp;
      sections->macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->str_offsets_dwo))
    {
      /* There can be only one.  */
      if (sections->str_offsets.s.section != NULL)
	return 0;
      sections->str_offsets.s.section = sectp;
      sections->str_offsets.size = bfd_section_size (sectp);
    }
  else
    {
      /* No other kind of section is valid.  */
      return 0;
    }

  return 1;
}

/* Create a dwo_unit object for the DWO unit with signature SIGNATURE.
   UNIT_INDEX is the index of the DWO unit in the DWP hash table.
   COMP_DIR is the DW_AT_comp_dir attribute of the referencing CU.
   This is for DWP version 1 files.  */

static struct dwo_unit *
create_dwo_unit_in_dwp_v1 (struct dwarf2_per_objfile *dwarf2_per_objfile,
			   struct dwp_file *dwp_file,
			   uint32_t unit_index,
			   const char *comp_dir,
			   ULONGEST signature, int is_debug_types)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  const struct dwp_hash_table *dwp_htab =
    is_debug_types ? dwp_file->tus : dwp_file->cus;
  bfd *dbfd = dwp_file->dbfd.get ();
  const char *kind = is_debug_types ? "TU" : "CU";
  struct dwo_file *dwo_file;
  struct dwo_unit *dwo_unit;
  struct virtual_v1_dwo_sections sections;
  void **dwo_file_slot;
  int i;

  gdb_assert (dwp_file->version == 1);

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Reading %s %s/%s in DWP V1 file: %s\n",
			  kind,
			  pulongest (unit_index), hex_string (signature),
			  dwp_file->name);
    }

  /* Fetch the sections of this DWO unit.
     Put a limit on the number of sections we look for so that bad data
     doesn't cause us to loop forever.  */

#define MAX_NR_V1_DWO_SECTIONS \
  (1 /* .debug_info or .debug_types */ \
   + 1 /* .debug_abbrev */ \
   + 1 /* .debug_line */ \
   + 1 /* .debug_loc */ \
   + 1 /* .debug_str_offsets */ \
   + 1 /* .debug_macro or .debug_macinfo */ \
   + 1 /* trailing zero */)

  memset (&sections, 0, sizeof (sections));

  for (i = 0; i < MAX_NR_V1_DWO_SECTIONS; ++i)
    {
      asection *sectp;
      uint32_t section_nr =
	read_4_bytes (dbfd,
		      dwp_htab->section_pool.v1.indices
		      + (unit_index + i) * sizeof (uint32_t));

      if (section_nr == 0)
	break;
      if (section_nr >= dwp_file->num_sections)
	{
	  error (_("Dwarf Error: bad DWP hash table, section number too large"
		   " [in module %s]"),
		 dwp_file->name);
	}

      sectp = dwp_file->elf_sections[section_nr];
      if (! locate_v1_virtual_dwo_sections (sectp, &sections))
	{
	  error (_("Dwarf Error: bad DWP hash table, invalid section found"
		   " [in module %s]"),
		 dwp_file->name);
	}
    }

  if (i < 2
      || dwarf2_section_empty_p (&sections.info_or_types)
      || dwarf2_section_empty_p (&sections.abbrev))
    {
      error (_("Dwarf Error: bad DWP hash table, missing DWO sections"
	       " [in module %s]"),
	     dwp_file->name);
    }
  if (i == MAX_NR_V1_DWO_SECTIONS)
    {
      error (_("Dwarf Error: bad DWP hash table, too many DWO sections"
	       " [in module %s]"),
	     dwp_file->name);
    }

  /* It's easier for the rest of the code if we fake a struct dwo_file and
     have dwo_unit "live" in that.  At least for now.

     The DWP file can be made up of a random collection of CUs and TUs.
     However, for each CU + set of TUs that came from the same original DWO
     file, we can combine them back into a virtual DWO file to save space
     (fewer struct dwo_file objects to allocate).  Remember that for really
     large apps there can be on the order of 8K CUs and 200K TUs, or more.  */

  std::string virtual_dwo_name =
    string_printf ("virtual-dwo/%d-%d-%d-%d",
		   get_section_id (&sections.abbrev),
		   get_section_id (&sections.line),
		   get_section_id (&sections.loc),
		   get_section_id (&sections.str_offsets));
  /* Can we use an existing virtual DWO file?  */
  dwo_file_slot = lookup_dwo_file_slot (dwarf2_per_objfile,
					virtual_dwo_name.c_str (),
					comp_dir);
  /* Create one if necessary.  */
  if (*dwo_file_slot == NULL)
    {
      if (dwarf_read_debug)
	{
	  fprintf_unfiltered (gdb_stdlog, "Creating virtual DWO: %s\n",
			      virtual_dwo_name.c_str ());
	}
      dwo_file = new struct dwo_file;
      dwo_file->dwo_name = obstack_strdup (&objfile->objfile_obstack,
					   virtual_dwo_name);
      dwo_file->comp_dir = comp_dir;
      dwo_file->sections.abbrev = sections.abbrev;
      dwo_file->sections.line = sections.line;
      dwo_file->sections.loc = sections.loc;
      dwo_file->sections.macinfo = sections.macinfo;
      dwo_file->sections.macro = sections.macro;
      dwo_file->sections.str_offsets = sections.str_offsets;
      /* The "str" section is global to the entire DWP file.  */
      dwo_file->sections.str = dwp_file->sections.str;
      /* The info or types section is assigned below to dwo_unit,
	 there's no need to record it in dwo_file.
	 Also, we can't simply record type sections in dwo_file because
	 we record a pointer into the vector in dwo_unit.  As we collect more
	 types we'll grow the vector and eventually have to reallocate space
	 for it, invalidating all copies of pointers into the previous
	 contents.  */
      *dwo_file_slot = dwo_file;
    }
  else
    {
      if (dwarf_read_debug)
	{
	  fprintf_unfiltered (gdb_stdlog, "Using existing virtual DWO: %s\n",
			      virtual_dwo_name.c_str ());
	}
      dwo_file = (struct dwo_file *) *dwo_file_slot;
    }

  dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
  dwo_unit->dwo_file = dwo_file;
  dwo_unit->signature = signature;
  dwo_unit->section =
    XOBNEW (&objfile->objfile_obstack, struct dwarf2_section_info);
  *dwo_unit->section = sections.info_or_types;
  /* dwo_unit->{offset,length,type_offset_in_tu} are set later.  */

  return dwo_unit;
}

/* Subroutine of create_dwo_unit_in_dwp_v2 to simplify it.
   Given a pointer to the containing section SECTION, and OFFSET,SIZE of the
   piece within that section used by a TU/CU, return a virtual section
   of just that piece.  */

static struct dwarf2_section_info
create_dwp_v2_or_v5_section (struct dwarf2_per_objfile *dwarf2_per_objfile,
			     struct dwarf2_section_info *section,
			     bfd_size_type offset, bfd_size_type size)
{
  struct dwarf2_section_info result;
  asection *sectp;

  gdb_assert (section != NULL);
  gdb_assert (!section->is_virtual);

  memset (&result, 0, sizeof (result));
  result.s.containing_section = section;
  result.is_virtual = true;

  if (size == 0)
    return result;

  sectp = get_section_bfd_section (section);

  /* Flag an error if the piece denoted by OFFSET,SIZE is outside the
     bounds of the real section.  This is a pretty-rare event, so just
     flag an error (easier) instead of a warning and trying to cope.  */
  if (sectp == NULL
      || offset + size > bfd_section_size (sectp))
    {
      error (_("Dwarf Error: Bad DWP V2 or V5 section info, doesn't fit"
	       " in section %s [in module %s]"),
	     sectp ? bfd_section_name (sectp) : "<unknown>",
	     objfile_name (dwarf2_per_objfile->objfile));
    }

  result.virtual_offset = offset;
  result.size = size;
  return result;
}

/* Create a dwo_unit object for the DWO unit with signature SIGNATURE.
   UNIT_INDEX is the index of the DWO unit in the DWP hash table.
   COMP_DIR is the DW_AT_comp_dir attribute of the referencing CU.
   This is for DWP version 2 files.  */

static struct dwo_unit *
create_dwo_unit_in_dwp_v2 (struct dwarf2_per_objfile *dwarf2_per_objfile,
			   struct dwp_file *dwp_file,
			   uint32_t unit_index,
			   const char *comp_dir,
			   ULONGEST signature, int is_debug_types)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  const struct dwp_hash_table *dwp_htab =
    is_debug_types ? dwp_file->tus : dwp_file->cus;
  bfd *dbfd = dwp_file->dbfd.get ();
  const char *kind = is_debug_types ? "TU" : "CU";
  struct dwo_file *dwo_file;
  struct dwo_unit *dwo_unit;
  struct virtual_v2_dwo_sections sections;
  void **dwo_file_slot;
  int i;

  gdb_assert (dwp_file->version == 2);

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Reading %s %s/%s in DWP V2 file: %s\n",
			  kind,
			  pulongest (unit_index), hex_string (signature),
			  dwp_file->name);
    }

  /* Fetch the section offsets of this DWO unit.  */

  memset (&sections, 0, sizeof (sections));

  for (i = 0; i < dwp_htab->nr_columns; ++i)
    {
      uint32_t offset = read_4_bytes (dbfd,
				      dwp_htab->section_pool.v2.offsets
				      + (((unit_index - 1) * dwp_htab->nr_columns
					  + i)
					 * sizeof (uint32_t)));
      uint32_t size = read_4_bytes (dbfd,
				    dwp_htab->section_pool.v2.sizes
				    + (((unit_index - 1) * dwp_htab->nr_columns
					+ i)
				       * sizeof (uint32_t)));

      switch (dwp_htab->section_pool.v2.section_ids[i])
	{
	case DW_SECT_INFO:
	case DW_SECT_TYPES:
	  sections.info_or_types_offset = offset;
	  sections.info_or_types_size = size;
	  break;
	case DW_SECT_ABBREV:
	  sections.abbrev_offset = offset;
	  sections.abbrev_size = size;
	  break;
	case DW_SECT_LINE:
	  sections.line_offset = offset;
	  sections.line_size = size;
	  break;
	case DW_SECT_LOC:
	  sections.loc_offset = offset;
	  sections.loc_size = size;
	  break;
	case DW_SECT_STR_OFFSETS:
	  sections.str_offsets_offset = offset;
	  sections.str_offsets_size = size;
	  break;
	case DW_SECT_MACINFO:
	  sections.macinfo_offset = offset;
	  sections.macinfo_size = size;
	  break;
	case DW_SECT_MACRO:
	  sections.macro_offset = offset;
	  sections.macro_size = size;
	  break;
	}
    }

  /* It's easier for the rest of the code if we fake a struct dwo_file and
     have dwo_unit "live" in that.  At least for now.

     The DWP file can be made up of a random collection of CUs and TUs.
     However, for each CU + set of TUs that came from the same original DWO
     file, we can combine them back into a virtual DWO file to save space
     (fewer struct dwo_file objects to allocate).  Remember that for really
     large apps there can be on the order of 8K CUs and 200K TUs, or more.  */

  std::string virtual_dwo_name =
    string_printf ("virtual-dwo/%ld-%ld-%ld-%ld",
		   (long) (sections.abbrev_size ? sections.abbrev_offset : 0),
		   (long) (sections.line_size ? sections.line_offset : 0),
		   (long) (sections.loc_size ? sections.loc_offset : 0),
		   (long) (sections.str_offsets_size
			   ? sections.str_offsets_offset : 0));
  /* Can we use an existing virtual DWO file?  */
  dwo_file_slot = lookup_dwo_file_slot (dwarf2_per_objfile,
					virtual_dwo_name.c_str (),
					comp_dir);
  /* Create one if necessary.  */
  if (*dwo_file_slot == NULL)
    {
      if (dwarf_read_debug)
	{
	  fprintf_unfiltered (gdb_stdlog, "Creating virtual DWO: %s\n",
			      virtual_dwo_name.c_str ());
	}
      dwo_file = new struct dwo_file;
      dwo_file->dwo_name = obstack_strdup (&objfile->objfile_obstack,
					   virtual_dwo_name);
      dwo_file->comp_dir = comp_dir;
      dwo_file->sections.abbrev =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.abbrev,
                                       sections.abbrev_offset,
                                       sections.abbrev_size);
      dwo_file->sections.line =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.line,
                                       sections.line_offset,
                                       sections.line_size);
      dwo_file->sections.loc =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.loc,
                                       sections.loc_offset, sections.loc_size);
      dwo_file->sections.macinfo =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.macinfo,
                                       sections.macinfo_offset,
                                       sections.macinfo_size);
      dwo_file->sections.macro =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.macro,
                                       sections.macro_offset,
                                       sections.macro_size);
      dwo_file->sections.str_offsets =
          create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                       &dwp_file->sections.str_offsets,
                                       sections.str_offsets_offset,
                                       sections.str_offsets_size);
      /* The "str" section is global to the entire DWP file.  */
      dwo_file->sections.str = dwp_file->sections.str;
      /* The info or types section is assigned below to dwo_unit,
         there's no need to record it in dwo_file.
         Also, we can't simply record type sections in dwo_file because
         we record a pointer into the vector in dwo_unit.  As we collect more
         types we'll grow the vector and eventually have to reallocate space
         for it, invalidating all copies of pointers into the previous
         contents.  */
      *dwo_file_slot = dwo_file;
    }
  else
    {
      if (dwarf_read_debug)
        {
          fprintf_unfiltered (gdb_stdlog, "Using existing virtual DWO: %s\n",
                              virtual_dwo_name.c_str ());
        }
      dwo_file = (struct dwo_file *) *dwo_file_slot;
    }

  dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
  dwo_unit->dwo_file = dwo_file;
  dwo_unit->signature = signature;
  dwo_unit->section =
    XOBNEW (&objfile->objfile_obstack, struct dwarf2_section_info);
  *dwo_unit->section = create_dwp_v2_or_v5_section
                         (dwarf2_per_objfile,
                          is_debug_types
                          ? &dwp_file->sections.types
                          : &dwp_file->sections.info,
                          sections.info_or_types_offset,
                          sections.info_or_types_size);
  /* dwo_unit->{offset,length,type_offset_in_tu} are set later.  */

  return dwo_unit;
}

/* Create a dwo_unit object for the DWO unit with signature SIGNATURE.
   UNIT_INDEX is the index of the DWO unit in the DWP hash table.
   COMP_DIR is the DW_AT_comp_dir attribute of the referencing CU.
   This is for DWP version 5 files.  */

static struct dwo_unit *
create_dwo_unit_in_dwp_v5 (struct dwarf2_per_objfile *dwarf2_per_objfile,
                           struct dwp_file *dwp_file,
                           uint32_t unit_index,
                           const char *comp_dir,
                           ULONGEST signature, int is_debug_types)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  const struct dwp_hash_table *dwp_htab =
    is_debug_types ? dwp_file->tus : dwp_file->cus;
  bfd *dbfd = dwp_file->dbfd.get ();
  const char *kind = is_debug_types ? "TU" : "CU";
  struct dwo_file *dwo_file;
  struct dwo_unit *dwo_unit;
  struct virtual_v2_dwo_sections sections;
  void **dwo_file_slot;
  int i;

  gdb_assert (dwp_file->version == 5);

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "Reading %s %s/%s in DWP V5 file: %s\n",
                          kind,
                          pulongest (unit_index), hex_string (signature),
                          dwp_file->name);
    }

  /* Fetch the section offsets of this DWO unit.  */

  memset (&sections, 0, sizeof (sections));

  for (i = 0; i < dwp_htab->nr_columns; ++i)
    {
      uint32_t offset = read_4_bytes (dbfd,
                                      dwp_htab->section_pool.v5.offsets
                                      + (((unit_index - 1)
                                          * dwp_htab->nr_columns
                                          + i)
                                         * sizeof (uint32_t)));
      uint32_t size = read_4_bytes (dbfd,
                                    dwp_htab->section_pool.v5.sizes
                                    + (((unit_index - 1) * dwp_htab->nr_columns
                                        + i)
                                       * sizeof (uint32_t)));

      switch (dwp_htab->section_pool.v5.section_ids[i])
        {
          case DW_SECT_ABBREV_V5:
            sections.abbrev_offset = offset;
            sections.abbrev_size = size;
            break;
          case DW_SECT_INFO_V5:
            sections.info_or_types_offset = offset;
            sections.info_or_types_size = size;
            break;
          case DW_SECT_LINE_V5:
            sections.line_offset = offset;
            sections.line_size = size;
            break;
          case DW_SECT_LOCLISTS_V5:
            sections.loclists_offset = offset;
            sections.loclists_size = size;
            break;
          case DW_SECT_MACRO_V5:
            sections.macro_offset = offset;
            sections.macro_size = size;
            break;
          case DW_SECT_RNGLISTS_V5:
            sections.rnglists_offset = offset;
            sections.rnglists_size = size;
            break;
          case DW_SECT_STR_OFFSETS_V5:
            sections.str_offsets_offset = offset;
            sections.str_offsets_size = size;
            break;
          case DW_SECT_RESERVED_V5:
          default:
            break;
        }
    }

  /* It's easier for the rest of the code if we fake a struct dwo_file and
     have dwo_unit "live" in that.  At least for now.

     The DWP file can be made up of a random collection of CUs and TUs.
     However, for each CU + set of TUs that came from the same original DWO
     file, we can combine them back into a virtual DWO file to save space
     (fewer struct dwo_file objects to allocate).  Remember that for really
     large apps there can be on the order of 8K CUs and 200K TUs, or more.  */

  std::string virtual_dwo_name =
    string_printf ("virtual-dwo/%ld-%ld-%ld-%ld-%ld-%ld",
                 (long) (sections.abbrev_size ? sections.abbrev_offset : 0),
                 (long) (sections.line_size ? sections.line_offset : 0),
                 (long) (sections.loclists_size ? sections.loclists_offset : 0),
                 (long) (sections.str_offsets_size
                            ? sections.str_offsets_offset : 0),
                 (long) (sections.macro_size ? sections.macro_offset : 0),
                 (long) (sections.rnglists_size ? sections.rnglists_offset: 0));
  /* Can we use an existing virtual DWO file?  */
  dwo_file_slot = lookup_dwo_file_slot (dwarf2_per_objfile,
                                        virtual_dwo_name.c_str (),
                                        comp_dir);
  /* Create one if necessary.  */
  if (*dwo_file_slot == NULL)
    {
      if (dwarf_read_debug)
        {
          fprintf_unfiltered (gdb_stdlog, "Creating virtual DWO: %s\n",
                              virtual_dwo_name.c_str ());
        }
      dwo_file = new struct dwo_file;
      dwo_file->dwo_name = obstack_strdup (&objfile->objfile_obstack,
                                           virtual_dwo_name);
      dwo_file->comp_dir = comp_dir;
      dwo_file->sections.abbrev =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.abbrev,
                                     sections.abbrev_offset,
                                     sections.abbrev_size);
      dwo_file->sections.line =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.line,
                                     sections.line_offset, sections.line_size);
      dwo_file->sections.macro =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.macro,
                                     sections.macro_offset,
                                     sections.macro_size);
      dwo_file->sections.loclists =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.loclists,
                                     sections.loclists_offset,
                                     sections.loclists_size);
      dwo_file->sections.rnglists =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.rnglists,
                                     sections.rnglists_offset,
                                     sections.rnglists_size);
      dwo_file->sections.str_offsets =
        create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                     &dwp_file->sections.str_offsets,
                                     sections.str_offsets_offset,
                                     sections.str_offsets_size);
      /* The "str" section is global to the entire DWP file.  */
      dwo_file->sections.str = dwp_file->sections.str;
      /* The info or types section is assigned below to dwo_unit,
         there's no need to record it in dwo_file.
         Also, we can't simply record type sections in dwo_file because
         we record a pointer into the vector in dwo_unit.  As we collect more
         types we'll grow the vector and eventually have to reallocate space
         for it, invalidating all copies of pointers into the previous
         contents.  */
      *dwo_file_slot = dwo_file;
    }
  else
    {
      if (dwarf_read_debug)
        {
          fprintf_unfiltered (gdb_stdlog, "Using existing virtual DWO: %s\n",
                              virtual_dwo_name.c_str ());
        }
      dwo_file = (struct dwo_file *) *dwo_file_slot;
    }

  dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
  dwo_unit->dwo_file = dwo_file;
  dwo_unit->signature = signature;
  dwo_unit->section =
    XOBNEW (&objfile->objfile_obstack, struct dwarf2_section_info);
  *dwo_unit->section = create_dwp_v2_or_v5_section (dwarf2_per_objfile,
                                              &dwp_file->sections.info,
                                              sections.info_or_types_offset,
                                              sections.info_or_types_size);
  /* dwo_unit->{offset,length,type_offset_in_tu} are set later.  */

  return dwo_unit;
}

/* Lookup the DWO unit with SIGNATURE in DWP_FILE.
   Returns NULL if the signature isn't found.  */

static struct dwo_unit *
lookup_dwo_unit_in_dwp (struct dwarf2_per_objfile *dwarf2_per_objfile,
			struct dwp_file *dwp_file, const char *comp_dir,
			ULONGEST signature, int is_debug_types)
{
  const struct dwp_hash_table *dwp_htab =
    is_debug_types ? dwp_file->tus : dwp_file->cus;
  bfd *dbfd = dwp_file->dbfd.get ();
  uint32_t mask = dwp_htab->nr_slots - 1;
  uint32_t hash = signature & mask;
  uint32_t hash2 = ((signature >> 32) & mask) | 1;
  unsigned int i;
  void **slot;
  struct dwo_unit find_dwo_cu;

  memset (&find_dwo_cu, 0, sizeof (find_dwo_cu));
  find_dwo_cu.signature = signature;
  slot = htab_find_slot (is_debug_types
			 ? dwp_file->loaded_tus
			 : dwp_file->loaded_cus,
			 &find_dwo_cu, INSERT);

  if (*slot != NULL)
    return (struct dwo_unit *) *slot;

  /* Use a for loop so that we don't loop forever on bad debug info.  */
  for (i = 0; i < dwp_htab->nr_slots; ++i)
    {
      ULONGEST signature_in_table;

      signature_in_table =
	read_8_bytes (dbfd, dwp_htab->hash_table + hash * sizeof (uint64_t));
      if (signature_in_table == signature)
	{
	  uint32_t unit_index =
	    read_4_bytes (dbfd,
			  dwp_htab->unit_table + hash * sizeof (uint32_t));

	  if (dwp_file->version == 1)
	    {
	      *slot = create_dwo_unit_in_dwp_v1 (dwarf2_per_objfile,
						 dwp_file, unit_index,
						 comp_dir, signature,
						 is_debug_types);
	    }
	  else if (dwp_file->version == 2)
	    {
	      *slot = create_dwo_unit_in_dwp_v2 (dwarf2_per_objfile,
						 dwp_file, unit_index,
						 comp_dir, signature,
						 is_debug_types);
	    }
	  else // dwp_file->version == 5
	    {
	      *slot = create_dwo_unit_in_dwp_v5 (dwarf2_per_objfile,
						 dwp_file, unit_index,
						 comp_dir, signature,
						 is_debug_types);
	    }
	  return (struct dwo_unit *) *slot;
	}
      if (signature_in_table == 0)
	return NULL;
      hash = (hash + hash2) & mask;
    }

  error (_("Dwarf Error: bad DWP hash table, lookup didn't terminate"
	   " [in module %s]"),
	 dwp_file->name);
}

/* Subroutine of open_dwo_file,open_dwp_file to simplify them.
   Open the file specified by FILE_NAME and hand it off to BFD for
   preliminary analysis.  Return a newly initialized bfd *, which
   includes a canonicalized copy of FILE_NAME.
   If IS_DWP is TRUE, we're opening a DWP file, otherwise a DWO file.
   SEARCH_CWD is true if the current directory is to be searched.
   It will be searched before debug-file-directory.
   If successful, the file is added to the bfd include table of the
   objfile's bfd (see gdb_bfd_record_inclusion).
   If unable to find/open the file, return NULL.
   NOTE: This function is derived from symfile_bfd_open.  */

static gdb_bfd_ref_ptr
try_open_dwop_file (struct dwarf2_per_objfile *dwarf2_per_objfile,
		    const char *file_name, int is_dwp, int search_cwd)
{
  int desc;
  /* Blech.  OPF_TRY_CWD_FIRST also disables searching the path list if
     FILE_NAME contains a '/'.  So we can't use it.  Instead prepend "."
     to debug_file_directory.  */
  const char *search_path;
  static const char dirname_separator_string[] = { DIRNAME_SEPARATOR, '\0' };

  gdb::unique_xmalloc_ptr<char> search_path_holder;
  if (search_cwd)
    {
      if (*debug_file_directory != '\0')
	{
	  search_path_holder.reset (concat (".", dirname_separator_string,
					    debug_file_directory,
					    (char *) NULL));
	  search_path = search_path_holder.get ();
	}
      else
	search_path = ".";
    }
  else
    search_path = debug_file_directory;

  search_path_holder.reset(
      concat(ldirname(dwarf2_per_objfile->objfile->original_name).c_str(),
	     dirname_separator_string, search_path, (char *) NULL));
  search_path = search_path_holder.get();

  openp_flags flags = OPF_RETURN_REALPATH;
  flags |= OPF_SEARCH_IN_PATH;

  gdb::unique_xmalloc_ptr<char> absolute_name;
  desc = openp (search_path, flags, file_name,
		O_RDONLY | O_BINARY, &absolute_name);
  if (desc < 0)
    return NULL;

  gdb_bfd_ref_ptr sym_bfd (gdb_bfd_open (absolute_name.get (),
					 gnutarget, desc));
  if (sym_bfd == NULL)
    return NULL;
  bfd_set_cacheable (sym_bfd.get (), 1);

  if (!bfd_check_format (sym_bfd.get (), bfd_object))
    return NULL;

  /* Success.  Record the bfd as having been included by the objfile's bfd.
     This is important because things like demangled_names_hash lives in the
     objfile's per_bfd space and may have references to things like symbol
     names that live in the DWO/DWP file's per_bfd space.  PR 16426.  */
  gdb_bfd_record_inclusion (dwarf2_per_objfile->objfile->obfd, sym_bfd.get ());

  return sym_bfd;
}

/* Try to open DWO file FILE_NAME.
   COMP_DIR is the DW_AT_comp_dir attribute.
   The result is the bfd handle of the file.
   If there is a problem finding or opening the file, return NULL.
   Upon success, the canonicalized path of the file is stored in the bfd,
   same as symfile_bfd_open.  */

static gdb_bfd_ref_ptr
open_dwo_file (struct dwarf2_per_objfile *dwarf2_per_objfile,
	       const char *file_name, const char *comp_dir)
{
  if (IS_ABSOLUTE_PATH (file_name))
    return try_open_dwop_file (dwarf2_per_objfile, file_name,
			       0 /*is_dwp*/, 0 /*search_cwd*/);

  /* Before trying the search path, try DWO_NAME in COMP_DIR.  */

  if (comp_dir != NULL)
    {
      char *path_to_try = concat (comp_dir, SLASH_STRING,
				  file_name, (char *) NULL);

      /* NOTE: If comp_dir is a relative path, this will also try the
	 search path, which seems useful.  */
      gdb_bfd_ref_ptr abfd (try_open_dwop_file (dwarf2_per_objfile,
						path_to_try,
						0 /*is_dwp*/,
						1 /*search_cwd*/));
      xfree (path_to_try);
      if (abfd != NULL)
	return abfd;
    }

  /* That didn't work, try debug-file-directory, which, despite its name,
     is a list of paths.  */

  if (*debug_file_directory == '\0')
    return NULL;

  return try_open_dwop_file (dwarf2_per_objfile, file_name,
			     0 /*is_dwp*/, 1 /*search_cwd*/);
}

/* This function is mapped across the sections and remembers the offset and
   size of each of the DWO debugging sections we are interested in.  */

static void
dwarf2_locate_dwo_sections (bfd *abfd, asection *sectp, void *dwo_sections_ptr)
{
  struct dwo_sections *dwo_sections = (struct dwo_sections *) dwo_sections_ptr;
  const struct dwop_section_names *names = &dwop_section_names;

  if (section_is_p (sectp->name, &names->abbrev_dwo))
    {
      dwo_sections->abbrev.s.section = sectp;
      dwo_sections->abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->info_dwo))
    {
      dwo_sections->info.s.section = sectp;
      dwo_sections->info.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->line_dwo))
    {
      dwo_sections->line.s.section = sectp;
      dwo_sections->line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->loc_dwo))
    {
      dwo_sections->loc.s.section = sectp;
      dwo_sections->loc.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macinfo_dwo))
    {
      dwo_sections->macinfo.s.section = sectp;
      dwo_sections->macinfo.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macro_dwo))
    {
      dwo_sections->macro.s.section = sectp;
      dwo_sections->macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p(sectp->name, &names->loclists_dwo))
    {
      dwo_sections->loclists.s.section = sectp;
      dwo_sections->loclists.size = bfd_section_size(sectp);
    }
  else if (section_is_p(sectp->name, &names->rnglists_dwo))
    {
      dwo_sections->rnglists.s.section = sectp;
      dwo_sections->rnglists.size = bfd_section_size(sectp);
    }
  else if (section_is_p (sectp->name, &names->str_dwo))
    {
      dwo_sections->str.s.section = sectp;
      dwo_sections->str.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->str_offsets_dwo))
    {
      dwo_sections->str_offsets.s.section = sectp;
      dwo_sections->str_offsets.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->types_dwo))
    {
      struct dwarf2_section_info type_section;

      memset (&type_section, 0, sizeof (type_section));
      type_section.s.section = sectp;
      type_section.size = bfd_section_size (sectp);
      dwo_sections->types.push_back (type_section);
    }
}

/* Initialize the use of the DWO file specified by DWO_NAME and referenced
   by PER_CU.  This is for the non-DWP case.
   The result is NULL if DWO_NAME can't be found.  */

static struct dwo_file *
open_and_init_dwo_file (struct dwarf2_per_cu_data *per_cu,
			const char *dwo_name, const char *comp_dir)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = per_cu->dwarf2_per_objfile;

  gdb_bfd_ref_ptr dbfd = open_dwo_file (dwarf2_per_objfile, dwo_name, comp_dir);
  if (dbfd == NULL)
    {
      if (dwarf_read_debug)
	fprintf_unfiltered (gdb_stdlog, "DWO file not found: %s\n", dwo_name);
      return NULL;
    }

  dwo_file_up dwo_file (new struct dwo_file);
  dwo_file->dwo_name = dwo_name;
  dwo_file->comp_dir = comp_dir;
  dwo_file->dbfd = std::move (dbfd);

  bfd_map_over_sections (dwo_file->dbfd.get (), dwarf2_locate_dwo_sections,
			 &dwo_file->sections);

  create_cus_hash_table (dwarf2_per_objfile, per_cu->cu, *dwo_file,
			 dwo_file->sections.info, dwo_file->cus);

  if (dwo_file->sections.types.size() > 0 || per_cu->dwarf_version < 5)
    {
      create_debug_types_hash_table (dwarf2_per_objfile, dwo_file.get (),
				     dwo_file->sections.types, dwo_file->tus);
    }
  else
    {
      create_debug_type_hash_table (dwarf2_per_objfile, dwo_file.get (),
				    &(dwo_file->sections.info), dwo_file->tus,
				    rcuh_kind::TYPE);
    }

  if (dwarf_read_debug)
    fprintf_unfiltered (gdb_stdlog, "DWO file found: %s\n", dwo_name);

  return dwo_file.release ();
}

/* This function is mapped across the sections and remembers the offset and
   size of each of the DWP debugging sections common to version 1 and 2 that
   we are interested in.  */

static void
dwarf2_locate_common_dwp_sections (bfd *abfd, asection *sectp,
				   void *dwp_file_ptr)
{
  struct dwp_file *dwp_file = (struct dwp_file *) dwp_file_ptr;
  const struct dwop_section_names *names = &dwop_section_names;
  unsigned int elf_section_nr = elf_section_data (sectp)->this_idx;

  /* Record the ELF section number for later lookup: this is what the
     .debug_cu_index,.debug_tu_index tables use in DWP V1.  */
  gdb_assert (elf_section_nr < dwp_file->num_sections);
  dwp_file->elf_sections[elf_section_nr] = sectp;

  /* Look for specific sections that we need.  */
  if (section_is_p (sectp->name, &names->str_dwo))
    {
      dwp_file->sections.str.s.section = sectp;
      dwp_file->sections.str.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->cu_index))
    {
      dwp_file->sections.cu_index.s.section = sectp;
      dwp_file->sections.cu_index.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->tu_index))
    {
      dwp_file->sections.tu_index.s.section = sectp;
      dwp_file->sections.tu_index.size = bfd_section_size (sectp);
    }
}

/* This function is mapped across the sections and remembers the offset and
   size of each of the DWP version 2 debugging sections that we are interested
   in.  This is split into a separate function because we don't know if we
   have version 1 or 2 or 5 until we parse the cu_index/tu_index sections.  */

static void
dwarf2_locate_v2_dwp_sections (bfd *abfd, asection *sectp, void *dwp_file_ptr)
{
  struct dwp_file *dwp_file = (struct dwp_file *) dwp_file_ptr;
  const struct dwop_section_names *names = &dwop_section_names;
  unsigned int elf_section_nr = elf_section_data (sectp)->this_idx;

  /* Record the ELF section number for later lookup: this is what the
     .debug_cu_index,.debug_tu_index tables use in DWP V1.  */
  gdb_assert (elf_section_nr < dwp_file->num_sections);
  dwp_file->elf_sections[elf_section_nr] = sectp;

  /* Look for specific sections that we need.  */
  if (section_is_p (sectp->name, &names->abbrev_dwo))
    {
      dwp_file->sections.abbrev.s.section = sectp;
      dwp_file->sections.abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->info_dwo))
    {
      dwp_file->sections.info.s.section = sectp;
      dwp_file->sections.info.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->line_dwo))
    {
      dwp_file->sections.line.s.section = sectp;
      dwp_file->sections.line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->loc_dwo))
    {
      dwp_file->sections.loc.s.section = sectp;
      dwp_file->sections.loc.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macinfo_dwo))
    {
      dwp_file->sections.macinfo.s.section = sectp;
      dwp_file->sections.macinfo.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macro_dwo))
    {
      dwp_file->sections.macro.s.section = sectp;
      dwp_file->sections.macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->str_offsets_dwo))
    {
      dwp_file->sections.str_offsets.s.section = sectp;
      dwp_file->sections.str_offsets.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->types_dwo))
    {
      dwp_file->sections.types.s.section = sectp;
      dwp_file->sections.types.size = bfd_section_size (sectp);
    }
}

/* This function is mapped across the sections and remembers the offset and
   size of each of the DWP version 5 debugging sections that we are interested
   in.  This is split into a separate function because we don't know if we
   have version 1 or 2 or 5 until we parse the cu_index/tu_index sections.  */

static void
dwarf2_locate_v5_dwp_sections (bfd *abfd, asection *sectp, void *dwp_file_ptr)
{
  struct dwp_file *dwp_file = (struct dwp_file *) dwp_file_ptr;
  const struct dwop_section_names *names = &dwop_section_names;
  unsigned int elf_section_nr = elf_section_data (sectp)->this_idx;

  /* Record the ELF section number for later lookup: this is what the
     .debug_cu_index,.debug_tu_index tables use in DWP V1.  */
  gdb_assert (elf_section_nr < dwp_file->num_sections);
  dwp_file->elf_sections[elf_section_nr] = sectp;

  /* Look for specific sections that we need.  */
  if (section_is_p (sectp->name, &names->abbrev_dwo))
    {
      dwp_file->sections.abbrev.s.section = sectp;
      dwp_file->sections.abbrev.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->info_dwo))
    {
      dwp_file->sections.info.s.section = sectp;
      dwp_file->sections.info.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->line_dwo))
   {
     dwp_file->sections.line.s.section = sectp;
     dwp_file->sections.line.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->loclists_dwo))
    {
      dwp_file->sections.loclists.s.section = sectp;
      dwp_file->sections.loclists.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->macro_dwo))
    {
      dwp_file->sections.macro.s.section = sectp;
      dwp_file->sections.macro.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->rnglists_dwo))
    {
      dwp_file->sections.rnglists.s.section = sectp;
      dwp_file->sections.rnglists.size = bfd_section_size (sectp);
    }
  else if (section_is_p (sectp->name, &names->str_offsets_dwo))
    {
      dwp_file->sections.str_offsets.s.section = sectp;
      dwp_file->sections.str_offsets.size = bfd_section_size (sectp);
    }
}

/* Hash function for dwp_file loaded CUs/TUs.  */

static hashval_t
hash_dwp_loaded_cutus (const void *item)
{
  const struct dwo_unit *dwo_unit = (const struct dwo_unit *) item;

  /* This drops the top 32 bits of the signature, but is ok for a hash.  */
  return dwo_unit->signature;
}

/* Equality function for dwp_file loaded CUs/TUs.  */

static int
eq_dwp_loaded_cutus (const void *a, const void *b)
{
  const struct dwo_unit *dua = (const struct dwo_unit *) a;
  const struct dwo_unit *dub = (const struct dwo_unit *) b;

  return dua->signature == dub->signature;
}

/* Allocate a hash table for dwp_file loaded CUs/TUs.  */

static htab_t
allocate_dwp_loaded_cutus_table (struct objfile *objfile)
{
  return htab_create_alloc_ex (3,
			       hash_dwp_loaded_cutus,
			       eq_dwp_loaded_cutus,
			       NULL,
			       &objfile->objfile_obstack,
			       hashtab_obstack_allocate,
			       dummy_obstack_deallocate);
}

/* Try to open DWP file FILE_NAME.
   The result is the bfd handle of the file.
   If there is a problem finding or opening the file, return NULL.
   Upon success, the canonicalized path of the file is stored in the bfd,
   same as symfile_bfd_open.  */

static gdb_bfd_ref_ptr
open_dwp_file (struct dwarf2_per_objfile *dwarf2_per_objfile,
	       const char *file_name)
{
  gdb_bfd_ref_ptr abfd (try_open_dwop_file (dwarf2_per_objfile, file_name,
					    1 /*is_dwp*/,
					    1 /*search_cwd*/));
  if (abfd != NULL)
    return abfd;

  /* Work around upstream bug 15652.
     http://sourceware.org/bugzilla/show_bug.cgi?id=15652
     [Whether that's a "bug" is debatable, but it is getting in our way.]
     We have no real idea where the dwp file is, because gdb's realpath-ing
     of the executable's path may have discarded the needed info.
     [IWBN if the dwp file name was recorded in the executable, akin to
     .gnu_debuglink, but that doesn't exist yet.]
     Strip the directory from FILE_NAME and search again.  */
  if (*debug_file_directory != '\0')
    {
      /* Don't implicitly search the current directory here.
	 If the user wants to search "." to handle this case,
	 it must be added to debug-file-directory.  */
      return try_open_dwop_file (dwarf2_per_objfile,
				 lbasename (file_name), 1 /*is_dwp*/,
				 0 /*search_cwd*/);
    }

  return NULL;
}

/* Initialize the use of the DWP file for the current objfile.
   By convention the name of the DWP file is ${objfile}.dwp.
   The result is NULL if it can't be found.  */

static std::unique_ptr<struct dwp_file>
open_and_init_dwp_file (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  struct objfile *objfile = dwarf2_per_objfile->objfile;

  /* Try to find first .dwp for the binary file before any symbolic links
     resolving.  */

  /* If the objfile is a debug file, find the name of the real binary
     file and get the name of dwp file from there.  */
  std::string dwp_name;
  if (objfile->separate_debug_objfile_backlink != NULL)
    {
      struct objfile *backlink = objfile->separate_debug_objfile_backlink;
      const char *backlink_basename = lbasename (backlink->original_name);

      dwp_name = ldirname (objfile->original_name) + SLASH_STRING + backlink_basename;
    }
  else
    dwp_name = objfile->original_name;

  dwp_name += ".dwp";

  gdb_bfd_ref_ptr dbfd (open_dwp_file (dwarf2_per_objfile, dwp_name.c_str ()));
  if (dbfd == NULL
      && strcmp (objfile->original_name, objfile_name (objfile)) != 0)
    {
      /* Try to find .dwp for the binary file after gdb_realpath resolving.  */
      dwp_name = objfile_name (objfile);
      dwp_name += ".dwp";
      dbfd = open_dwp_file (dwarf2_per_objfile, dwp_name.c_str ());
    }

  if (dbfd == NULL)
    {
      if (dwarf_read_debug)
	fprintf_unfiltered (gdb_stdlog, "DWP file not found: %s\n", dwp_name.c_str ());
      return std::unique_ptr<dwp_file> ();
    }

  const char *name = bfd_get_filename (dbfd.get ());
  std::unique_ptr<struct dwp_file> dwp_file
    (new struct dwp_file (name, std::move (dbfd)));

  dwp_file->num_sections = elf_numsections (dwp_file->dbfd);
  dwp_file->elf_sections =
    OBSTACK_CALLOC (&objfile->objfile_obstack,
		    dwp_file->num_sections, asection *);

  bfd_map_over_sections (dwp_file->dbfd.get (),
			 dwarf2_locate_common_dwp_sections,
			 dwp_file.get ());

  dwp_file->cus = create_dwp_hash_table (dwarf2_per_objfile, dwp_file.get (),
					 0);

  dwp_file->tus = create_dwp_hash_table (dwarf2_per_objfile, dwp_file.get (),
					 1);

  /* The DWP file version is stored in the hash table.  Oh well.  */
  if (dwp_file->cus && dwp_file->tus
      && dwp_file->cus->version != dwp_file->tus->version)
    {
      /* Technically speaking, we should try to limp along, but this is
	 pretty bizarre.  We use pulongest here because that's the established
	 portability solution (e.g, we cannot use %u for uint32_t).  */
      error (_("Dwarf Error: DWP file CU version %s doesn't match"
	       " TU version %s [in DWP file %s]"),
	     pulongest (dwp_file->cus->version),
	     pulongest (dwp_file->tus->version), dwp_name.c_str ());
    }

  if (dwp_file->cus)
    dwp_file->version = dwp_file->cus->version;
  else if (dwp_file->tus)
    dwp_file->version = dwp_file->tus->version;
  else
    dwp_file->version = 2;

  if (dwp_file->version == 2)
    bfd_map_over_sections (dwp_file->dbfd.get (),
			   dwarf2_locate_v2_dwp_sections,
			   dwp_file.get ());
  else if (dwp_file->version == 5)
    bfd_map_over_sections (dwp_file->dbfd.get (),
			   dwarf2_locate_v5_dwp_sections,
			   dwp_file.get ());

  dwp_file->loaded_cus = allocate_dwp_loaded_cutus_table (objfile);
  dwp_file->loaded_tus = allocate_dwp_loaded_cutus_table (objfile);

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "DWP file found: %s\n", dwp_file->name);
      fprintf_unfiltered (gdb_stdlog,
			  "    %s CUs, %s TUs\n",
			  pulongest (dwp_file->cus ? dwp_file->cus->nr_units : 0),
			  pulongest (dwp_file->tus ? dwp_file->tus->nr_units : 0));
    }

  return dwp_file;
}

/* Wrapper around open_and_init_dwp_file, only open it once.  */

static struct dwp_file *
get_dwp_file (struct dwarf2_per_objfile *dwarf2_per_objfile)
{
  if (! dwarf2_per_objfile->dwp_checked)
    {
      dwarf2_per_objfile->dwp_file
	= open_and_init_dwp_file (dwarf2_per_objfile);
      dwarf2_per_objfile->dwp_checked = 1;
    }
  return dwarf2_per_objfile->dwp_file.get ();
}

/* Subroutine of lookup_dwo_comp_unit, lookup_dwo_type_unit.
   Look up the CU/TU with signature SIGNATURE, either in DWO file DWO_NAME
   or in the DWP file for the objfile, referenced by THIS_UNIT.
   If non-NULL, comp_dir is the DW_AT_comp_dir attribute.
   IS_DEBUG_TYPES is non-zero if reading a TU, otherwise read a CU.

   This is called, for example, when wanting to read a variable with a
   complex location.  Therefore we don't want to do file i/o for every call.
   Therefore we don't want to look for a DWO file on every call.
   Therefore we first see if we've already seen SIGNATURE in a DWP file,
   then we check if we've already seen DWO_NAME, and only THEN do we check
   for a DWO file.

   The result is a pointer to the dwo_unit object or NULL if we didn't find it
   (dwo_id mismatch or couldn't find the DWO/DWP file).  */

static struct dwo_unit *
lookup_dwo_cutu (struct dwarf2_per_cu_data *this_unit,
		 const char *dwo_name, const char *comp_dir,
		 ULONGEST signature, int is_debug_types)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile = this_unit->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  const char *kind = is_debug_types ? "TU" : "CU";
  void **dwo_file_slot;
  struct dwo_file *dwo_file;
  struct dwp_file *dwp_file;

  /* First see if there's a DWP file.
     If we have a DWP file but didn't find the DWO inside it, don't
     look for the original DWO file.  It makes gdb behave differently
     depending on whether one is debugging in the build tree.  */

  dwp_file = get_dwp_file (dwarf2_per_objfile);
  if (dwp_file != NULL)
    {
      const struct dwp_hash_table *dwp_htab =
	is_debug_types ? dwp_file->tus : dwp_file->cus;

      if (dwp_htab != NULL)
	{
	  struct dwo_unit *dwo_cutu =
	    lookup_dwo_unit_in_dwp (dwarf2_per_objfile, dwp_file, comp_dir,
				    signature, is_debug_types);

	  if (dwo_cutu != NULL)
	    {
	      if (dwarf_read_debug)
		{
		  fprintf_unfiltered (gdb_stdlog,
				      "Virtual DWO %s %s found: @%s\n",
				      kind, hex_string (signature),
				      host_address_to_string (dwo_cutu));
		}
	      return dwo_cutu;
	    }
	}
    }
  else
    {
      /* No DWP file, look for the DWO file.  */

      dwo_file_slot = lookup_dwo_file_slot (dwarf2_per_objfile,
					    dwo_name, comp_dir);
      if (*dwo_file_slot == NULL)
	{
	  /* Read in the file and build a table of the CUs/TUs it contains.  */
	  *dwo_file_slot = open_and_init_dwo_file (this_unit, dwo_name, comp_dir);
	}
      /* NOTE: This will be NULL if unable to open the file.  */
      dwo_file = (struct dwo_file *) *dwo_file_slot;

      if (dwo_file != NULL)
	{
	  struct dwo_unit *dwo_cutu = NULL;

	  if (is_debug_types && dwo_file->tus)
	    {
	      struct dwo_unit find_dwo_cutu;

	      memset (&find_dwo_cutu, 0, sizeof (find_dwo_cutu));
	      find_dwo_cutu.signature = signature;
	      dwo_cutu
		= (struct dwo_unit *) htab_find (dwo_file->tus, &find_dwo_cutu);
	    }
	  else if (!is_debug_types && dwo_file->cus)
	    {
	      struct dwo_unit find_dwo_cutu;

	      memset (&find_dwo_cutu, 0, sizeof (find_dwo_cutu));
	      find_dwo_cutu.signature = signature;
	      dwo_cutu = (struct dwo_unit *)htab_find (dwo_file->cus,
						       &find_dwo_cutu);
	    }

	  if (dwo_cutu != NULL)
	    {
	      if (dwarf_read_debug)
		{
		  fprintf_unfiltered (gdb_stdlog, "DWO %s %s(%s) found: @%s\n",
				      kind, dwo_name, hex_string (signature),
				      host_address_to_string (dwo_cutu));
		}
	      return dwo_cutu;
	    }
	}
    }

  /* We didn't find it.  This could mean a dwo_id mismatch, or
     someone deleted the DWO/DWP file, or the search path isn't set up
     correctly to find the file.  */

  if (dwarf_read_debug)
    {
      fprintf_unfiltered (gdb_stdlog, "DWO %s %s(%s) not found\n",
			  kind, dwo_name, hex_string (signature));
    }

  /* This is a warning and not a complaint because it can be caused by
     pilot error (e.g., user accidentally deleting the DWO).  */
  {
    /* Print the name of the DWP file if we looked there, helps the user
       better diagnose the problem.  */
    std::string dwp_text;

    if (dwp_file != NULL)
      dwp_text = string_printf (" [in DWP file %s]",
				lbasename (dwp_file->name));

    warning (_("Could not find DWO %s %s(%s)%s referenced by %s at offset %s"
	       " [in module %s]"),
	     kind, dwo_name, hex_string (signature),
	     dwp_text.c_str (),
	     this_unit->is_debug_types ? "TU" : "CU",
	     sect_offset_str (this_unit->sect_off), objfile_name (objfile));
  }
  return NULL;
}

/* Lookup the DWO CU DWO_NAME/SIGNATURE referenced from THIS_CU.
   See lookup_dwo_cutu_unit for details.  */

static struct dwo_unit *
lookup_dwo_comp_unit (struct dwarf2_per_cu_data *this_cu,
		      const char *dwo_name, const char *comp_dir,
		      ULONGEST signature)
{
  return lookup_dwo_cutu (this_cu, dwo_name, comp_dir, signature, 0);
}

/* Lookup the DWO TU DWO_NAME/SIGNATURE referenced from THIS_TU.
   See lookup_dwo_cutu_unit for details.  */

static struct dwo_unit *
lookup_dwo_type_unit (struct signatured_type *this_tu,
		      const char *dwo_name, const char *comp_dir)
{
  return lookup_dwo_cutu (&this_tu->per_cu, dwo_name, comp_dir, this_tu->signature, 1);
}

/* Traversal function for queue_and_load_all_dwo_tus.  */

static int
queue_and_load_dwo_tu (void **slot, void *info)
{
  struct dwo_unit *dwo_unit = (struct dwo_unit *) *slot;
  struct dwarf2_per_cu_data *per_cu = (struct dwarf2_per_cu_data *) info;
  ULONGEST signature = dwo_unit->signature;
  struct signatured_type *sig_type =
    lookup_dwo_signatured_type (per_cu->cu, signature);

  if (sig_type != NULL)
    {
      struct dwarf2_per_cu_data *sig_cu = &sig_type->per_cu;

      /* We pass NULL for DEPENDENT_CU because we don't yet know if there's
	 a real dependency of PER_CU on SIG_TYPE.  That is detected later
	 while processing PER_CU.  */
      if (maybe_queue_comp_unit (NULL, sig_cu, per_cu->cu->language))
	load_full_type_unit (sig_cu);
      per_cu->imported_symtabs_push (sig_cu);
    }

  return 1;
}

/* Queue all TUs contained in the DWO of PER_CU to be read in.
   The DWO may have the only definition of the type, though it may not be
   referenced anywhere in PER_CU.  Thus we have to load *all* its TUs.
   http://sourceware.org/bugzilla/show_bug.cgi?id=15021  */

static void
queue_and_load_all_dwo_tus (struct dwarf2_per_cu_data *per_cu)
{
  struct dwo_unit *dwo_unit;
  struct dwo_file *dwo_file;

  gdb_assert (!per_cu->is_debug_types);
  gdb_assert (get_dwp_file (per_cu->dwarf2_per_objfile) == NULL);
  gdb_assert (per_cu->cu != NULL);

  dwo_unit = per_cu->cu->dwo_unit;
  gdb_assert (dwo_unit != NULL);

  dwo_file = dwo_unit->dwo_file;
  if (dwo_file->tus != NULL)
    htab_traverse_noresize (dwo_file->tus, queue_and_load_dwo_tu, per_cu);
}

/* Read in various DIEs.  */

/* DW_AT_abstract_origin inherits whole DIEs (not just their attributes).
   Inherit only the children of the DW_AT_abstract_origin DIE not being
   already referenced by DW_AT_abstract_origin from the children of the
   current DIE.  */

static void
inherit_abstract_dies (struct die_info *die, struct dwarf2_cu *cu)
{
  struct die_info *child_die;
  sect_offset *offsetp;
  /* Parent of DIE - referenced by DW_AT_abstract_origin.  */
  struct die_info *origin_die;
  /* Iterator of the ORIGIN_DIE children.  */
  struct die_info *origin_child_die;
  struct attribute *attr;
  struct dwarf2_cu *origin_cu;
  struct pending **origin_previous_list_in_scope;

  attr = dwarf2_attr (die, DW_AT_abstract_origin, cu);
  if (!attr)
    return;

  /* Note that following die references may follow to a die in a
     different cu.  */

  origin_cu = cu;
  origin_die = follow_die_ref (die, attr, &origin_cu);

  /* We're inheriting ORIGIN's children into the scope we'd put DIE's
     symbols in.  */
  origin_previous_list_in_scope = origin_cu->list_in_scope;
  origin_cu->list_in_scope = cu->list_in_scope;

  if (die->tag != origin_die->tag
      && !(die->tag == DW_TAG_inlined_subroutine
	   && origin_die->tag == DW_TAG_subprogram))
    complaint (_("DIE %s and its abstract origin %s have different tags"),
	       sect_offset_str (die->sect_off),
	       sect_offset_str (origin_die->sect_off));

  std::vector<sect_offset> offsets;

  for (child_die = die->child;
       child_die && child_die->tag;
       child_die = sibling_die (child_die))
    {
      struct die_info *child_origin_die;
      struct dwarf2_cu *child_origin_cu;

      /* We are trying to process concrete instance entries:
	 DW_TAG_call_site DIEs indeed have a DW_AT_abstract_origin tag, but
	 it's not relevant to our analysis here. i.e. detecting DIEs that are
	 present in the abstract instance but not referenced in the concrete
	 one.  */
      if (child_die->tag == DW_TAG_call_site
	  || child_die->tag == DW_TAG_GNU_call_site)
	continue;

      /* For each CHILD_DIE, find the corresponding child of
	 ORIGIN_DIE.  If there is more than one layer of
	 DW_AT_abstract_origin, follow them all; there shouldn't be,
	 but GCC versions at least through 4.4 generate this (GCC PR
	 40573).  */
      child_origin_die = child_die;
      child_origin_cu = cu;
      while (1)
	{
	  attr = dwarf2_attr (child_origin_die, DW_AT_abstract_origin,
			      child_origin_cu);
	  if (attr == NULL)
	    break;
	  child_origin_die = follow_die_ref (child_origin_die, attr,
					     &child_origin_cu);
	}

      /* According to DWARF3 3.3.8.2 #3 new entries without their abstract
	 counterpart may exist.  */
      if (child_origin_die != child_die)
	{
	  if (child_die->tag != child_origin_die->tag
	      && !(child_die->tag == DW_TAG_inlined_subroutine
		   && child_origin_die->tag == DW_TAG_subprogram))
	    complaint (_("Child DIE %s and its abstract origin %s have "
			 "different tags"),
		       sect_offset_str (child_die->sect_off),
		       sect_offset_str (child_origin_die->sect_off));
	  if (child_origin_die->parent != origin_die)
	    complaint (_("Child DIE %s and its abstract origin %s have "
			 "different parents"),
		       sect_offset_str (child_die->sect_off),
		       sect_offset_str (child_origin_die->sect_off));
	  else
	    offsets.push_back (child_origin_die->sect_off);
	}
    }
  std::sort (offsets.begin (), offsets.end ());
  sect_offset *offsets_end = offsets.data () + offsets.size ();
  for (offsetp = offsets.data () + 1; offsetp < offsets_end; offsetp++)
    if (offsetp[-1] == *offsetp)
      complaint (_("Multiple children of DIE %s refer "
		   "to DIE %s as their abstract origin"),
		 sect_offset_str (die->sect_off), sect_offset_str (*offsetp));

  offsetp = offsets.data ();
  origin_child_die = origin_die->child;
  while (origin_child_die && origin_child_die->tag)
    {
      /* Is ORIGIN_CHILD_DIE referenced by any of the DIE children?  */
      while (offsetp < offsets_end
	     && *offsetp < origin_child_die->sect_off)
	offsetp++;
      if (offsetp >= offsets_end
	  || *offsetp > origin_child_die->sect_off)
	{
	  /* Found that ORIGIN_CHILD_DIE is really not referenced.
	     Check whether we're already processing ORIGIN_CHILD_DIE.
	     This can happen with mutually referenced abstract_origins.
	     PR 16581.  */
	  if (!origin_child_die->in_process)
	    process_die (origin_child_die, origin_cu);
	}
      origin_child_die = sibling_die (origin_child_die);
    }
  origin_cu->list_in_scope = origin_previous_list_in_scope;

  if (cu != origin_cu)
    compute_delayed_physnames (origin_cu);
}

static void
read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  struct context_stack *newobj;
  CORE_ADDR lowpc;
  CORE_ADDR highpc;
  struct die_info *child_die;
  struct attribute *attr, *call_line, *call_file;
  const char *name;
  CORE_ADDR baseaddr;
  struct block *block;
  int inlined_func = (die->tag == DW_TAG_inlined_subroutine);
  std::vector<struct symbol *> template_args;
  struct template_symbol *templ_func = NULL;

  if (inlined_func)
    {
      /* If we do not have call site information, we can't show the
	 caller of this inlined function.  That's too confusing, so
	 only use the scope for local variables.  */
      call_line = dwarf2_attr (die, DW_AT_call_line, cu);
      call_file = dwarf2_attr (die, DW_AT_call_file, cu);
      if (call_line == NULL || call_file == NULL)
	{
	  read_lexical_block_scope (die, cu);
	  return;
	}
    }

  baseaddr = ANOFFSET (objfile->section_offsets,
		       SECT_OFF_TEXT (objfile));

  name = dwarf2_name (die, cu);

  /* Ignore functions with missing or empty names.  These are actually
     illegal according to the DWARF standard.  */
  if (name == NULL)
    {
      complaint (_("missing name for subprogram DIE at %s"),
		 sect_offset_str (die->sect_off));
      return;
    }

  /* Ignore functions with missing or invalid low and high pc attributes.  */
  if (dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL)
      <= PC_BOUNDS_INVALID)
    {
      attr = dwarf2_attr (die, DW_AT_external, cu);
      if (!attr || !DW_UNSND (attr))
	complaint (_("cannot get low and high bounds "
		     "for subprogram DIE at %s"),
		   sect_offset_str (die->sect_off));
      return;
    }

  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
  highpc = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);

  /* If we have any template arguments, then we must allocate a
     different sort of symbol.  */
  for (child_die = die->child; child_die; child_die = sibling_die (child_die))
    {
      if (child_die->tag == DW_TAG_template_type_param
	  || child_die->tag == DW_TAG_template_value_param)
	{
	  templ_func = allocate_template_symbol (objfile);
	  templ_func->subclass = SYMBOL_TEMPLATE;
	  break;
	}
    }

  newobj = cu->get_builder ()->push_context (0, lowpc);
  newobj->name = new_symbol (die, read_type_die (die, cu), cu,
			     (struct symbol *) templ_func);

  if (dwarf2_flag_true_p (die, DW_AT_main_subprogram, cu))
    set_objfile_main_name (objfile, newobj->name->linkage_name (),
			   cu->language);

  /* If there is a location expression for DW_AT_frame_base, record
     it.  */
  attr = dwarf2_attr (die, DW_AT_frame_base, cu);
  if (attr != nullptr)
    dwarf2_symbol_mark_computed (attr, newobj->name, cu, 1);

  /* If there is a location for the static link, record it.  */
  newobj->static_link = NULL;
  attr = dwarf2_attr (die, DW_AT_static_link, cu);
  if (attr != nullptr)
    {
      newobj->static_link
	= XOBNEW (&objfile->objfile_obstack, struct dynamic_prop);
      attr_to_dynamic_prop (attr, die, cu, newobj->static_link,
			    dwarf2_per_cu_addr_type (cu->per_cu));
    }

  cu->list_in_scope = cu->get_builder ()->get_local_symbols ();

  if (die->child != NULL)
    {
      child_die = die->child;
      while (child_die && child_die->tag)
	{
	  if (child_die->tag == DW_TAG_template_type_param
	      || child_die->tag == DW_TAG_template_value_param)
	    {
	      struct symbol *arg = new_symbol (child_die, NULL, cu);

	      if (arg != NULL)
		template_args.push_back (arg);
	    }
	  else
	    process_die (child_die, cu);
	  child_die = sibling_die (child_die);
	}
    }

  inherit_abstract_dies (die, cu);

  /* If we have a DW_AT_specification, we might need to import using
     directives from the context of the specification DIE.  See the
     comment in determine_prefix.  */
  if (cu->language == language_cplus
      && dwarf2_attr (die, DW_AT_specification, cu))
    {
      struct dwarf2_cu *spec_cu = cu;
      struct die_info *spec_die = die_specification (die, &spec_cu);

      while (spec_die)
	{
	  child_die = spec_die->child;
	  while (child_die && child_die->tag)
	    {
	      if (child_die->tag == DW_TAG_imported_module)
		process_die (child_die, spec_cu);
	      child_die = sibling_die (child_die);
	    }

	  /* In some cases, GCC generates specification DIEs that
	     themselves contain DW_AT_specification attributes.  */
	  spec_die = die_specification (spec_die, &spec_cu);
	}
    }

  struct context_stack cstk = cu->get_builder ()->pop_context ();
  /* Make a block for the local symbols within.  */
  block = cu->get_builder ()->finish_block (cstk.name, cstk.old_blocks,
				     cstk.static_link, lowpc, highpc);

  /* For C++, set the block's scope.  */
  if ((cu->language == language_cplus
       || cu->language == language_fortran
       || cu->language == language_d
       || cu->language == language_rust)
      && cu->processing_has_namespace_info)
    block_set_scope (block, determine_prefix (die, cu),
		     &objfile->objfile_obstack);

  /* If we have address ranges, record them.  */
  dwarf2_record_block_ranges (die, block, baseaddr, cu);

  gdbarch_make_symbol_special (gdbarch, cstk.name, objfile);

  /* Attach template arguments to function.  */
  if (!template_args.empty ())
    {
      gdb_assert (templ_func != NULL);

      templ_func->n_template_arguments = template_args.size ();
      templ_func->template_arguments
        = XOBNEWVEC (&objfile->objfile_obstack, struct symbol *,
		     templ_func->n_template_arguments);
      memcpy (templ_func->template_arguments,
	      template_args.data (),
	      (templ_func->n_template_arguments * sizeof (struct symbol *)));

      /* Make sure that the symtab is set on the new symbols.  Even
	 though they don't appear in this symtab directly, other parts
	 of gdb assume that symbols do, and this is reasonably
	 true.  */
      for (symbol *sym : template_args)
	symbol_set_symtab (sym, symbol_symtab (templ_func));
    }

  /* In C++, we can have functions nested inside functions (e.g., when
     a function declares a class that has methods).  This means that
     when we finish processing a function scope, we may need to go
     back to building a containing block's symbol lists.  */
  *cu->get_builder ()->get_local_symbols () = cstk.locals;
  cu->get_builder ()->set_local_using_directives (cstk.local_using_directives);

  /* If we've finished processing a top-level function, subsequent
     symbols go in the file symbol list.  */
  if (cu->get_builder ()->outermost_context_p ())
    cu->list_in_scope = cu->get_builder ()->get_file_symbols ();
}

/* Process all the DIES contained within a lexical block scope.  Start
   a new scope, process the dies, and then close the scope.  */

static void
read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  CORE_ADDR lowpc, highpc;
  struct die_info *child_die;
  CORE_ADDR baseaddr;

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  /* Ignore blocks with missing or invalid low and high pc attributes.  */
  /* ??? Perhaps consider discontiguous blocks defined by DW_AT_ranges
     as multiple lexical blocks?  Handling children in a sane way would
     be nasty.  Might be easier to properly extend generic blocks to
     describe ranges.  */
  switch (dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
    {
    case PC_BOUNDS_NOT_PRESENT:
      /* DW_TAG_lexical_block has no attributes, process its children as if
	 there was no wrapping by that DW_TAG_lexical_block.
	 GCC does no longer produces such DWARF since GCC r224161.  */
      for (child_die = die->child;
	   child_die != NULL && child_die->tag;
	   child_die = sibling_die (child_die))
	process_die (child_die, cu);
      return;
    case PC_BOUNDS_INVALID:
      return;
    }
  lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
  highpc = gdbarch_adjust_dwarf2_addr (gdbarch, highpc + baseaddr);

  cu->get_builder ()->push_context (0, lowpc);
  if (die->child != NULL)
    {
      child_die = die->child;
      while (child_die && child_die->tag)
	{
	  process_die (child_die, cu);
	  child_die = sibling_die (child_die);
	}
    }
  inherit_abstract_dies (die, cu);
  struct context_stack cstk = cu->get_builder ()->pop_context ();

  if (*cu->get_builder ()->get_local_symbols () != NULL
      || (*cu->get_builder ()->get_local_using_directives ()) != NULL)
    {
      struct block *block
        = cu->get_builder ()->finish_block (0, cstk.old_blocks, NULL,
				     cstk.start_addr, highpc);

      /* Note that recording ranges after traversing children, as we
         do here, means that recording a parent's ranges entails
         walking across all its children's ranges as they appear in
         the address map, which is quadratic behavior.

         It would be nicer to record the parent's ranges before
         traversing its children, simply overriding whatever you find
         there.  But since we don't even decide whether to create a
         block until after we've traversed its children, that's hard
         to do.  */
      dwarf2_record_block_ranges (die, block, baseaddr, cu);
    }
  *cu->get_builder ()->get_local_symbols () = cstk.locals;
  cu->get_builder ()->set_local_using_directives (cstk.local_using_directives);
}

/* Read in DW_TAG_call_site and insert it to CU->call_site_htab.  */

static void
read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  CORE_ADDR pc, baseaddr;
  struct attribute *attr;
  struct call_site *call_site, call_site_local;
  void **slot;
  int nparams;
  struct die_info *child_die;

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  attr = dwarf2_attr (die, DW_AT_call_return_pc, cu);
  if (attr == NULL)
    {
      /* This was a pre-DWARF-5 GNU extension alias
	 for DW_AT_call_return_pc.  */
      attr = dwarf2_attr (die, DW_AT_low_pc, cu);
    }
  if (!attr)
    {
      complaint (_("missing DW_AT_call_return_pc for DW_TAG_call_site "
		   "DIE %s [in module %s]"),
		 sect_offset_str (die->sect_off), objfile_name (objfile));
      return;
    }
  pc = attr_value_as_address (attr) + baseaddr;
  pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc);

  if (cu->call_site_htab == NULL)
    cu->call_site_htab = htab_create_alloc_ex (16, core_addr_hash, core_addr_eq,
					       NULL, &objfile->objfile_obstack,
					       hashtab_obstack_allocate, NULL);
  call_site_local.pc = pc;
  slot = htab_find_slot (cu->call_site_htab, &call_site_local, INSERT);
  if (*slot != NULL)
    {
      complaint (_("Duplicate PC %s for DW_TAG_call_site "
		   "DIE %s [in module %s]"),
		 paddress (gdbarch, pc), sect_offset_str (die->sect_off),
		 objfile_name (objfile));
      return;
    }

  /* Count parameters at the caller.  */

  nparams = 0;
  for (child_die = die->child; child_die && child_die->tag;
       child_die = sibling_die (child_die))
    {
      if (child_die->tag != DW_TAG_call_site_parameter
          && child_die->tag != DW_TAG_GNU_call_site_parameter)
	{
	  complaint (_("Tag %d is not DW_TAG_call_site_parameter in "
		       "DW_TAG_call_site child DIE %s [in module %s]"),
		     child_die->tag, sect_offset_str (child_die->sect_off),
		     objfile_name (objfile));
	  continue;
	}

      nparams++;
    }

  call_site
    = ((struct call_site *)
       obstack_alloc (&objfile->objfile_obstack,
		      sizeof (*call_site)
		      + (sizeof (*call_site->parameter) * (nparams - 1))));
  *slot = call_site;
  memset (call_site, 0, sizeof (*call_site) - sizeof (*call_site->parameter));
  call_site->pc = pc;

  if (dwarf2_flag_true_p (die, DW_AT_call_tail_call, cu)
      || dwarf2_flag_true_p (die, DW_AT_GNU_tail_call, cu))
    {
      struct die_info *func_die;

      /* Skip also over DW_TAG_inlined_subroutine.  */
      for (func_die = die->parent;
	   func_die && func_die->tag != DW_TAG_subprogram
	   && func_die->tag != DW_TAG_subroutine_type;
	   func_die = func_die->parent);

      /* DW_AT_call_all_calls is a superset
	 of DW_AT_call_all_tail_calls.  */
      if (func_die
          && !dwarf2_flag_true_p (func_die, DW_AT_call_all_calls, cu)
          && !dwarf2_flag_true_p (func_die, DW_AT_GNU_all_call_sites, cu)
	  && !dwarf2_flag_true_p (func_die, DW_AT_call_all_tail_calls, cu)
	  && !dwarf2_flag_true_p (func_die, DW_AT_GNU_all_tail_call_sites, cu))
	{
	  /* TYPE_TAIL_CALL_LIST is not interesting in functions where it is
	     not complete.  But keep CALL_SITE for look ups via call_site_htab,
	     both the initial caller containing the real return address PC and
	     the final callee containing the current PC of a chain of tail
	     calls do not need to have the tail call list complete.  But any
	     function candidate for a virtual tail call frame searched via
	     TYPE_TAIL_CALL_LIST must have the tail call list complete to be
	     determined unambiguously.  */
	}
      else
	{
	  struct type *func_type = NULL;

	  if (func_die)
	    func_type = get_die_type (func_die, cu);
	  if (func_type != NULL)
	    {
	      gdb_assert (TYPE_CODE (func_type) == TYPE_CODE_FUNC);

	      /* Enlist this call site to the function.  */
	      call_site->tail_call_next = TYPE_TAIL_CALL_LIST (func_type);
	      TYPE_TAIL_CALL_LIST (func_type) = call_site;
	    }
	  else
	    complaint (_("Cannot find function owning DW_TAG_call_site "
			 "DIE %s [in module %s]"),
		       sect_offset_str (die->sect_off), objfile_name (objfile));
	}
    }

  attr = dwarf2_attr (die, DW_AT_call_target, cu);
  if (attr == NULL)
    attr = dwarf2_attr (die, DW_AT_GNU_call_site_target, cu);
  if (attr == NULL)
    attr = dwarf2_attr (die, DW_AT_call_origin, cu);
  if (attr == NULL)
    {
      /* This was a pre-DWARF-5 GNU extension alias for DW_AT_call_origin.  */
      attr = dwarf2_attr (die, DW_AT_abstract_origin, cu);
    }
  SET_FIELD_DWARF_BLOCK (call_site->target, NULL);
  if (!attr || (attr_form_is_block (attr) && DW_BLOCK (attr)->size == 0))
    /* Keep NULL DWARF_BLOCK.  */;
  else if (attr_form_is_block (attr))
    {
      struct dwarf2_locexpr_baton *dlbaton;

      dlbaton = XOBNEW (&objfile->objfile_obstack, struct dwarf2_locexpr_baton);
      dlbaton->data = DW_BLOCK (attr)->data;
      dlbaton->size = DW_BLOCK (attr)->size;
      dlbaton->per_cu = cu->per_cu;

      SET_FIELD_DWARF_BLOCK (call_site->target, dlbaton);
    }
  else if (attr_form_is_ref (attr))
    {
      struct dwarf2_cu *target_cu = cu;
      struct die_info *target_die;

      target_die = follow_die_ref (die, attr, &target_cu);
      gdb_assert (target_cu->per_cu->dwarf2_per_objfile->objfile == objfile);
      if (die_is_declaration (target_die, target_cu))
	{
	  const char *target_physname;

	  /* Prefer the mangled name; otherwise compute the demangled one.  */
	  target_physname = dw2_linkage_name (target_die, target_cu);
	  if (target_physname == NULL)
	    target_physname = dwarf2_physname (NULL, target_die, target_cu);
	  if (target_physname == NULL)
	    complaint (_("DW_AT_call_target target DIE has invalid "
		         "physname, for referencing DIE %s [in module %s]"),
		       sect_offset_str (die->sect_off), objfile_name (objfile));
	  else
	    SET_FIELD_PHYSNAME (call_site->target, target_physname);
	}
      else
	{
	  CORE_ADDR lowpc;

	  /* DW_AT_entry_pc should be preferred.  */
	  if (dwarf2_get_pc_bounds (target_die, &lowpc, NULL, target_cu, NULL)
	      <= PC_BOUNDS_INVALID)
	    complaint (_("DW_AT_call_target target DIE has invalid "
		         "low pc, for referencing DIE %s [in module %s]"),
		       sect_offset_str (die->sect_off), objfile_name (objfile));
	  else
	    {
	      lowpc = gdbarch_adjust_dwarf2_addr (gdbarch, lowpc + baseaddr);
	      SET_FIELD_PHYSADDR (call_site->target, lowpc);
	    }
	}
    }
  else
    complaint (_("DW_TAG_call_site DW_AT_call_target is neither "
		 "block nor reference, for DIE %s [in module %s]"),
	       sect_offset_str (die->sect_off), objfile_name (objfile));

  call_site->per_cu = cu->per_cu;

  for (child_die = die->child;
       child_die && child_die->tag;
       child_die = sibling_die (child_die))
    {
      struct call_site_parameter *parameter;
      struct attribute *loc, *origin;

      if (child_die->tag != DW_TAG_call_site_parameter
          && child_die->tag != DW_TAG_GNU_call_site_parameter)
	{
	  /* Already printed the complaint above.  */
	  continue;
	}

      gdb_assert (call_site->parameter_count < nparams);
      parameter = &call_site->parameter[call_site->parameter_count];

      /* DW_AT_location specifies the register number or DW_AT_abstract_origin
	 specifies DW_TAG_formal_parameter.  Value of the data assumed for the
	 register is contained in DW_AT_call_value.  */

      loc = dwarf2_attr (child_die, DW_AT_location, cu);
      origin = dwarf2_attr (child_die, DW_AT_call_parameter, cu);
      if (origin == NULL)
	{
	  /* This was a pre-DWARF-5 GNU extension alias
	     for DW_AT_call_parameter.  */
	  origin = dwarf2_attr (child_die, DW_AT_abstract_origin, cu);
	}
      if (loc == NULL && origin != NULL && attr_form_is_ref (origin))
	{
	  parameter->kind = CALL_SITE_PARAMETER_PARAM_OFFSET;

	  sect_offset sect_off
	    = (sect_offset) dwarf2_get_ref_die_offset (origin);
	  if (!offset_in_cu_p (&cu->header, sect_off))
	    {
	      /* As DW_OP_GNU_parameter_ref uses CU-relative offset this
		 binding can be done only inside one CU.  Such referenced DIE
		 therefore cannot be even moved to DW_TAG_partial_unit.  */
	      complaint (_("DW_AT_call_parameter offset is not in CU for "
			   "DW_TAG_call_site child DIE %s [in module %s]"),
			 sect_offset_str (child_die->sect_off),
			 objfile_name (objfile));
	      continue;
	    }
	  parameter->u.param_cu_off
	    = (cu_offset) (sect_off - cu->header.sect_off);
	}
      else if (loc == NULL || origin != NULL || !attr_form_is_block (loc))
	{
	  complaint (_("No DW_FORM_block* DW_AT_location for "
		       "DW_TAG_call_site child DIE %s [in module %s]"),
		     sect_offset_str (child_die->sect_off), objfile_name (objfile));
	  continue;
	}
      else
	{
	  parameter->u.dwarf_reg = dwarf_block_to_dwarf_reg
	    (DW_BLOCK (loc)->data, &DW_BLOCK (loc)->data[DW_BLOCK (loc)->size]);
	  if (parameter->u.dwarf_reg != -1)
	    parameter->kind = CALL_SITE_PARAMETER_DWARF_REG;
	  else if (dwarf_block_to_sp_offset (gdbarch, DW_BLOCK (loc)->data,
				    &DW_BLOCK (loc)->data[DW_BLOCK (loc)->size],
					     &parameter->u.fb_offset))
	    parameter->kind = CALL_SITE_PARAMETER_FB_OFFSET;
	  else
	    {
	      complaint (_("Only single DW_OP_reg or DW_OP_fbreg is supported "
			   "for DW_FORM_block* DW_AT_location is supported for "
			   "DW_TAG_call_site child DIE %s "
			   "[in module %s]"),
			 sect_offset_str (child_die->sect_off),
			 objfile_name (objfile));
	      continue;
	    }
	}

      attr = dwarf2_attr (child_die, DW_AT_call_value, cu);
      if (attr == NULL)
	attr = dwarf2_attr (child_die, DW_AT_GNU_call_site_value, cu);
      if (!attr_form_is_block (attr))
	{
	  complaint (_("No DW_FORM_block* DW_AT_call_value for "
		       "DW_TAG_call_site child DIE %s [in module %s]"),
		     sect_offset_str (child_die->sect_off),
		     objfile_name (objfile));
	  continue;
	}
      parameter->value = DW_BLOCK (attr)->data;
      parameter->value_size = DW_BLOCK (attr)->size;

      /* Parameters are not pre-cleared by memset above.  */
      parameter->data_value = NULL;
      parameter->data_value_size = 0;
      call_site->parameter_count++;

      attr = dwarf2_attr (child_die, DW_AT_call_data_value, cu);
      if (attr == NULL)
	attr = dwarf2_attr (child_die, DW_AT_GNU_call_site_data_value, cu);
      if (attr != nullptr)
	{
	  if (!attr_form_is_block (attr))
	    complaint (_("No DW_FORM_block* DW_AT_call_data_value for "
			 "DW_TAG_call_site child DIE %s [in module %s]"),
		       sect_offset_str (child_die->sect_off),
		       objfile_name (objfile));
	  else
	    {
	      parameter->data_value = DW_BLOCK (attr)->data;
	      parameter->data_value_size = DW_BLOCK (attr)->size;
	    }
	}
    }
}

/* Helper function for read_variable.  If DIE represents a virtual
   table, then return the type of the concrete object that is
   associated with the virtual table.  Otherwise, return NULL.  */

static struct type *
rust_containing_type (struct die_info *die, struct dwarf2_cu *cu)
{
  struct attribute *attr = dwarf2_attr (die, DW_AT_type, cu);
  if (attr == NULL)
    return NULL;

  /* Find the type DIE.  */
  struct die_info *type_die = NULL;
  struct dwarf2_cu *type_cu = cu;

  if (attr_form_is_ref (attr))
    type_die = follow_die_ref (die, attr, &type_cu);
  if (type_die == NULL)
    return NULL;

  if (dwarf2_attr (type_die, DW_AT_containing_type, type_cu) == NULL)
    return NULL;
  return die_containing_type (type_die, type_cu);
}

/* Read a variable (DW_TAG_variable) DIE and create a new symbol.  */

static void
read_variable (struct die_info *die, struct dwarf2_cu *cu)
{
  struct rust_vtable_symbol *storage = NULL;

  if (cu->language == language_rust)
    {
      struct type *containing_type = rust_containing_type (die, cu);

      if (containing_type != NULL)
	{
	  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;

	  storage = new (&objfile->objfile_obstack) rust_vtable_symbol ();
	  initialize_objfile_symbol (storage);
	  storage->concrete_type = containing_type;
	  storage->subclass = SYMBOL_RUST_VTABLE;
	}
    }

  struct symbol *res = new_symbol (die, NULL, cu, storage);
  struct attribute *abstract_origin
    = dwarf2_attr (die, DW_AT_abstract_origin, cu);
  struct attribute *loc = dwarf2_attr (die, DW_AT_location, cu);
  if (res == NULL && loc && abstract_origin)
    {
      /* We have a variable without a name, but with a location and an abstract
	 origin.  This may be a concrete instance of an abstract variable
	 referenced from an DW_OP_GNU_variable_value, so save it to find it back
	 later.  */
      struct dwarf2_cu *origin_cu = cu;
      struct die_info *origin_die
	= follow_die_ref (die, abstract_origin, &origin_cu);
      dwarf2_per_objfile *dpo = cu->per_cu->dwarf2_per_objfile;
      dpo->abstract_to_concrete[origin_die->sect_off].push_back (die->sect_off);
    }
}

/* Call CALLBACK from DW_AT_ranges attribute value OFFSET
   reading .debug_rnglists.
   Callback's type should be:
    void (CORE_ADDR range_beginning, CORE_ADDR range_end)
   Return true if the attributes are present and valid, otherwise,
   return false.  */

template <typename Callback>
static bool
dwarf2_rnglists_process (unsigned offset, struct dwarf2_cu *cu,
			 dwarf_tag tag, Callback &&callback)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  bfd *obfd = objfile->obfd;
  /* Base address selection entry.  */
  CORE_ADDR base;
  int found_base;
  const gdb_byte *buffer;
  CORE_ADDR baseaddr;
  bool overflow = false;
  ULONGEST addr_index;
  struct dwarf2_section_info *rnglists_section;
  int ignore_dwo_unit = 0;

  found_base = cu->base_known;
  base = cu->base_address;

  /* If the DW_AT_ranges attribute was part of a DW_TAG_skeleton_unit that was
     changed into a DW_TAG_compile_unit after calling read_cutu_die_from_dwo, we
     want to use the rnglist in the objfile rather than the one in the
     dwo_unit. */
  if (tag == DW_TAG_compile_unit &&
      cu->cu_ranges_from_skeleton)
    ignore_dwo_unit = 1;


  /* Otherwise, if there's a dwo_unit, we want that rnglist. */
  if (cu->dwo_unit &&
      cu->dwo_unit->dwo_file->sections.rnglists.size > 0 &&
      !ignore_dwo_unit)
    {
      rnglists_section = &cu->dwo_unit->dwo_file->sections.rnglists;
    }
  else
    {
      rnglists_section = &dwarf2_per_objfile->rnglists;
    }

  dwarf2_read_section (objfile, rnglists_section);
  if (offset >= rnglists_section->size)
    {
      complaint (_("Offset %d out of bounds for DW_AT_ranges attribute"),
		 offset);
      return false;
    }
  buffer = rnglists_section->buffer + offset;

  baseaddr = ANOFFSET (objfile->section_offsets,
		       SECT_OFF_TEXT (objfile));
  // FIXME: We should calculate the end per range list entry, not per section.
  const gdb_byte *buf_end = (rnglists_section->buffer
			    + rnglists_section->size);

  while (1)
    {
      /* Initialize it due to a false compiler warning.  */
      CORE_ADDR range_beginning = 0, range_end = 0;
      unsigned int bytes_read;

      if (buffer == buf_end)
	{
	  overflow = true;
	  break;
	}
      const auto rlet = static_cast<enum dwarf_range_list_entry>(*buffer++);
      switch (rlet)
	{
	case DW_RLE_end_of_list:
	  break;
	case DW_RLE_base_address:
	  if (buffer + cu->header.addr_size > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  base = read_address (obfd, buffer, cu, &bytes_read);
	  buffer += bytes_read;
	  found_base = 1;
	  break;
	case DW_RLE_base_addressx:
	  addr_index = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  base = read_addr_index (cu, addr_index);
	  found_base = 1;
	  break;
	case DW_RLE_start_length:
	  if (buffer + cu->header.addr_size > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  range_beginning = read_address (obfd, buffer, cu, &bytes_read);
	  buffer += bytes_read;
	  if (buffer > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  range_end = (range_beginning
		       + read_unsigned_leb128 (obfd, buffer, &bytes_read));
	  buffer += bytes_read;
	  break;
	case DW_RLE_startx_length:
	  addr_index = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  range_beginning = read_addr_index (cu, addr_index);
	  if (buffer > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  range_end = (range_beginning
		       + read_unsigned_leb128 (obfd, buffer, &bytes_read));
	  buffer += bytes_read;
	  break;
	case DW_RLE_offset_pair:
	  range_beginning = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  if (buffer > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  range_end = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  break;
	case DW_RLE_start_end:
	  if (buffer + 2 * cu->header.addr_size > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  range_beginning = read_address (obfd, buffer, cu, &bytes_read);
	  buffer += bytes_read;
	  range_end = read_address (obfd, buffer, cu, &bytes_read);
	  buffer += bytes_read;
	  break;
	case DW_RLE_startx_endx:
	  addr_index = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  range_beginning = read_addr_index (cu, addr_index);
	  if (buffer > buf_end)
	    {
	      overflow = true;
	      break;
	    }
	  addr_index = read_unsigned_leb128 (obfd, buffer, &bytes_read);
	  buffer += bytes_read;
	  range_end = read_addr_index (cu, addr_index);
	  break;
	default:
	  complaint (_("Invalid .debug_rnglists data (no base address)"));
	  return false;
	}
      if (buffer > buf_end)
	overflow = true;
      if (rlet == DW_RLE_end_of_list || overflow)
	break;
      if (rlet == DW_RLE_base_address || rlet == DW_RLE_base_addressx)
	continue;

      if (!found_base)
	{
	  /* We have no valid base address for the ranges
	     data.  */
	  complaint (_("Invalid .debug_rnglists data (no base address)"));
	  return false;
	}

      if (range_beginning > range_end)
	{
	  /* Inverted range entries are invalid.  */
	  complaint (_("Invalid .debug_rnglists data (inverted range)"));
	  return false;
	}

      /* Empty range entries have no effect.  */
      if (range_beginning == range_end)
	continue;

      /* DW_RLE_offset_pair needs the base address added to the addresses */
      if (rlet == DW_RLE_offset_pair)
	{
	  range_beginning += base;
	  range_end += base;
	}

      /* Sometimes a function is inlined or removed, leaving behind a range with
	start address of zero.  Ignore the range and continue.  */
      if (range_beginning + baseaddr == 0
	  && !dwarf2_per_objfile->has_section_at_zero)
	  continue;
      callback (range_beginning, range_end);
    }

  if (overflow)
    {
      complaint (_("Offset %d is not terminated "
		   "for DW_AT_ranges attribute"),
		 offset);
      return false;
    }

  return true;
}

/* Call CALLBACK from DW_AT_ranges attribute value OFFSET reading .debug_ranges.
   Callback's type should be:
    void (CORE_ADDR range_beginning, CORE_ADDR range_end)
   Return 1 if the attributes are present and valid, otherwise, return 0.  */

template <typename Callback>
static int
dwarf2_ranges_process (unsigned offset, struct dwarf2_cu *cu,
		       dwarf_tag tag,
		       Callback &&callback)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
      = cu->per_cu->dwarf2_per_objfile;
  struct objfile *objfile = dwarf2_per_objfile->objfile;
  struct comp_unit_head *cu_header = &cu->header;
  bfd *obfd = objfile->obfd;
  unsigned int addr_size = cu_header->addr_size;
  CORE_ADDR mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
  /* Base address selection entry.  */
  CORE_ADDR base;
  int found_base;
  unsigned int dummy;
  const gdb_byte *buffer;
  CORE_ADDR baseaddr;

  if (cu_header->version >= 5)
    return dwarf2_rnglists_process (offset, cu, tag, callback);

  found_base = cu->base_known;
  base = cu->base_address;

  dwarf2_read_section (objfile, &dwarf2_per_objfile->ranges);
  if (offset >= dwarf2_per_objfile->ranges.size)
    {
      complaint (_("Offset %d out of bounds for DW_AT_ranges attribute"),
		 offset);
      return 0;
    }
  buffer = dwarf2_per_objfile->ranges.buffer + offset;

  baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));

  while (1)
    {
      CORE_ADDR range_beginning, range_end;

      range_beginning = read_address (obfd, buffer, cu, &dummy);
      buffer += addr_size;
      range_end = read_address (obfd, buffer, cu, &dummy);
      buffer += addr_size;
      offset += 2 * addr_size;

      /* An end of list marker is a pair of zero addresses.  */
      if (range_beginning == 0 && range_end == 0)
	/* Found the end of list entry.  */
	break;

      /* Each base address selection entry is a pair of 2 values.
	 The first is the largest possible address, the second is
	 the base address.  Check for a base address here.  */
      if ((range_beginning & mask) == mask)
	{
	  /* If we found the largest possible address, then we already
	     have the base address in range_end.  */
	  base = range_end;
	  found_base = 1;
	  continue;
	}

      if (!found_base)
	{
	  /* We have no valid base address for the ranges
	     data.  */
	  complaint (_("Invalid .debug_ranges data (no base address)"));
	  return 0;
	}

      if (range_beginning > range_end)
	{
	  /* Inverted range entries are invalid.  */
	  complaint (_("Invalid .debug_ranges data (inverted range)"));
	  return 0;
	}

      /* Empty range entries have no effect.  */
      if (range_beginning == range_end)
	continue;

      range_beginning += base;
      range_end += base;

      /* A not-uncommon case of bad debug info.
	 Don't pollute the addrmap with bad data.  */
      if (range_beginning + baseaddr == 0
	  && !dwarf2_per_objfile->has_section_at_zero)
	{
	  complaint (_(".debug_ranges entry has start address of zero"
		       " [in module %s]"), objfile_name (objfile));
	  continue;
	}

      callback (range_beginning, range_end);
    }

  return 1;
}

/* Get low and high pc attributes from DW_AT_ranges attribute value OFFSET.
   Return 1 if the attributes are present and valid, otherwise, return 0.
   If RANGES_PST is not NULL we should setup `objfile->psymtabs_addrmap'.  */

static int
dwarf2_ranges_read (unsigned offset, CORE_ADDR *low_return,
		    CORE_ADDR *high_return, struct dwarf2_cu *cu,
		    struct partial_symtab *ranges_pst, dwarf_tag tag)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  const CORE_ADDR baseaddr = ANOFFSET (objfile->section_offsets,
				       SECT_OFF_TEXT (objfile));
  int low_set = 0;
  CORE_ADDR low = 0;
  CORE_ADDR high = 0;
  int retval;

  retval = dwarf2_ranges_process (offset, cu, tag,
    [&] (CORE_ADDR range_beginning, CORE_ADDR range_end)
    {
      if (ranges_pst != NULL)
	{
	  CORE_ADDR lowpc;
	  CORE_ADDR highpc;

	  lowpc = (gdbarch_adjust_dwarf2_addr (gdbarch,
					       range_beginning + baseaddr)
		   - baseaddr);
	  highpc = (gdbarch_adjust_dwarf2_addr (gdbarch,
						range_end + baseaddr)
		    - baseaddr);
	  addrmap_set_empty (objfile->partial_symtabs->psymtabs_addrmap,
			     lowpc, highpc - 1, ranges_pst);
	}

      /* FIXME: This is recording everything as a low-high
	 segment of consecutive addresses.  We should have a
	 data structure for discontiguous block ranges
	 instead.  */
      if (! low_set)
	{
	  low = range_beginning;
	  high = range_end;
	  low_set = 1;
	}
      else
	{
	  if (range_beginning < low)
	    low = range_beginning;
	  if (range_end > high)
	    high = range_end;
	}
    });
  if (!retval)
    return 0;

  if (! low_set)
    /* If the first entry is an end-of-list marker, the range
       describes an empty scope, i.e. no instructions.  */
    return 0;

  if (low_return)
    *low_return = low;
  if (high_return)
    *high_return = high;
  return 1;
}

/* Get low and high pc attributes from a die.  See enum pc_bounds_kind
   definition for the return value.  *LOWPC and *HIGHPC are set iff
   neither PC_BOUNDS_NOT_PRESENT nor PC_BOUNDS_INVALID are returned.  */

static enum pc_bounds_kind
dwarf2_get_pc_bounds (struct die_info *die, CORE_ADDR *lowpc,
		      CORE_ADDR *highpc, struct dwarf2_cu *cu,
		      struct partial_symtab *pst)
{
  struct dwarf2_per_objfile *dwarf2_per_objfile
    = cu->per_cu->dwarf2_per_objfile;
  struct attribute *attr;
  struct attribute *attr_high;
  CORE_ADDR low = 0;
  CORE_ADDR high = 0;
  enum pc_bounds_kind ret;

  attr_high = dwarf2_attr (die, DW_AT_high_pc, cu);
  if (attr_high)
    {
      attr = dwarf2_attr (die, DW_AT_low_pc, cu);
      if (attr != nullptr)
        {
	  low = attr_value_as_address (attr);
	  high = attr_value_as_address (attr_high);
	  if (cu->header.version >= 4 && attr_form_is_constant (attr_high))
	    high += low;
	}
      else
	/* Found high w/o low attribute.  */
	return PC_BOUNDS_INVALID;

      /* Found consecutive range of addresses.  */
      ret = PC_BOUNDS_HIGH_LOW;
    }
  else
    {
      attr = dwarf2_attr (die, DW_AT_ranges, cu);
      if (attr != NULL)
	{
	  ULONGEST ranges_offset = calculate_ranges_offset (*cu, *attr, die->tag);
	  if (!dwarf2_ranges_read (ranges_offset, &low, &high, cu, pst,
				   die->tag))
	    return PC_BOUNDS_INVALID;
	  /* Found discontinuous range of addresses.  */
	  ret = PC_BOUNDS_RANGES;
	}
      else
	return PC_BOUNDS_NOT_PRESENT;
    }

  /* partial_die_info::read has also the strict LOW < HIGH requirement.  */
  if (high <= low)
    return PC_BOUNDS_INVALID;

  /* When using the GNU linker, .gnu.linkonce. sections are used to
     eliminate duplicate copies of functions and vtables and such.
     The linker will arbitrarily choose one and discard the others.
     The AT_*_pc values for such functions refer to local labels in
     these sections.  If the section from that file was discarded, the
     labels are not in the output, so the relocs get a value of 0.
     If this is a discarded function, mark the pc bounds as invalid,
     so that GDB will ignore it.  */
  if (low == 0 && !dwarf2_per_objfile->has_section_at_zero)
    return PC_BOUNDS_INVALID;

  *lowpc = low;
  if (highpc)
    *highpc = high;
  return ret;
}

/* Assuming that DIE represents a subprogram DIE or a lexical block, get
   its low and high PC addresses.  Do nothing if these addresses could not
   be determined.  Otherwise, set LOWPC to the low address if it is smaller,
   and HIGHPC to the high address if greater than HIGHPC.  */

static void
dwarf2_get_subprogram_pc_bounds (struct die_info *die,
                                 CORE_ADDR *lowpc, CORE_ADDR *highpc,
                                 struct dwarf2_cu *cu)
{
  CORE_ADDR low, high;
  struct die_info *child = die->child;

  if (dwarf2_get_pc_bounds (die, &low, &high, cu, NULL) >= PC_BOUNDS_RANGES)
    {
      *lowpc = std::min (*lowpc, low);
      *highpc = std::max (*highpc, high);
    }

  /* If the language does not allow nested subprograms (either inside
     subprograms or lexical blocks), we're done.  */
  if (cu->language != language_ada)
    return;

  /* Check all the children of the given DIE.  If it contains nested
     subprograms, then check their pc bounds.  Likewise, we need to
     check lexical blocks as well, as they may also contain subprogram
     definitions.  */
  while (child && child->tag)
    {
      if (child->tag == DW_TAG_subprogram
          || child->tag == DW_TAG_lexical_block)
        dwarf2_get_subprogram_pc_bounds (child, lowpc, highpc, cu);
      child = sibling_die (child);
    }
}

/* Get the low and high pc's represented by the scope DIE, and store
   them in *LOWPC and *HIGHPC.  If the correct values can't be
   determined, set *LOWPC to -1 and *HIGHPC to 0.  */

static void
get_scope_pc_bounds (struct die_info *die,
		     CORE_ADDR *lowpc, CORE_ADDR *highpc,
		     struct dwarf2_cu *cu)
{
  CORE_ADDR best_low = (CORE_ADDR) -1;
  CORE_ADDR best_high = (CORE_ADDR) 0;
  CORE_ADDR current_low, current_high;

  if (dwarf2_get_pc_bounds (die, &current_low, &current_high, cu, NULL)
      >= PC_BOUNDS_RANGES)
    {
      best_low = current_low;
      best_high = current_high;
    }
  else
    {
      struct die_info *child = die->child;

      while (child && child->tag)
	{
	  switch (child->tag) {
	  case DW_TAG_subprogram:
            dwarf2_get_subprogram_pc_bounds (child, &best_low, &best_high, cu);
	    break;
	  case DW_TAG_namespace:
	  case DW_TAG_module:
	    /* FIXME: carlton/2004-01-16: Should we do this for
	       DW_TAG_class_type/DW_TAG_structure_type, too?  I think
	       that current GCC's always emit the DIEs corresponding
	       to definitions of methods of classes as children of a
	       DW_TAG_compile_unit or DW_TAG_namespace (as opposed to
	       the DIEs giving the declarations, which could be
	       anywhere).  But I don't see any reason why the
	       standards says that they have to be there.  */
	    get_scope_pc_bounds (child, &current_low, &current_high, cu);

	    if (current_low != ((CORE_ADDR) -1))
	      {
		best_low = std::min (best_low, current_low);
		best_high = std::max (best_high, current_high);
	      }
	    break;
	  default:
	    /* Ignore.  */
	    break;
	  }

	  child = sibling_die (child);
	}
    }

  *lowpc = best_low;
  *highpc = best_high;
}

/* Record the address ranges for BLOCK, offset by BASEADDR, as given
   in DIE.  */

static void
dwarf2_record_block_ranges (struct die_info *die, struct block *block,
                            CORE_ADDR baseaddr, struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  struct attribute *attr;
  struct attribute *attr_high;

  attr_high = dwarf2_attr (die, DW_AT_high_pc, cu);
  if (attr_high)
    {
      attr = dwarf2_attr (die, DW_AT_low_pc, cu);
      if (attr != nullptr)
        {
          CORE_ADDR low = attr_value_as_address (attr);
	  CORE_ADDR high = attr_value_as_address (attr_high);

	  if (cu->header.version >= 4 && attr_form_is_constant (attr_high))
	    high += low;

	  low = gdbarch_adjust_dwarf2_addr (gdbarch, low + baseaddr);
	  high = gdbarch_adjust_dwarf2_addr (gdbarch, high + baseaddr);
	  cu->get_builder ()->record_block_range (block, low, high - 1);
        }
    }

  attr = dwarf2_attr (die, DW_AT_ranges, cu);
  if (attr != nullptr)
    {
      ULONGEST offset = calculate_ranges_offset (*cu, *attr, die->tag);
      std::vector<blockrange> blockvec;
      dwarf2_ranges_process (offset, cu, die->tag,
	[&] (CORE_ADDR start, CORE_ADDR end)
	{
	  start += baseaddr;
	  end += baseaddr;
	  start = gdbarch_adjust_dwarf2_addr (gdbarch, start);
	  end = gdbarch_adjust_dwarf2_addr (gdbarch, end);
	  cu->get_builder ()->record_block_range (block, start, end - 1);
	  blockvec.emplace_back (start, end);
	});

      BLOCK_RANGES(block) = make_blockranges (objfile, blockvec);
    }
}

/* Check whether the producer field indicates either of GCC < 4.6, or the
   Intel C/C++ compiler, and cache the result in CU.  */

static void
check_producer (struct dwarf2_cu *cu)
{
  int major, minor;

  if (cu->producer == NULL)
    {
      /* For unknown compilers expect their behavior is DWARF version
	 compliant.

	 GCC started to support .debug_types sections by -gdwarf-4 since
	 gcc-4.5.x.  As the .debug_types sections are missing DW_AT_producer
	 for their space efficiency GDB cannot workaround gcc-4.5.x -gdwarf-4
	 combination.  gcc-4.5.x -gdwarf-4 binaries have DW_AT_accessibility
	 interpreted incorrectly by GDB now - GCC PR debug/48229.  */
    }
  else if (producer_is_gcc (cu->producer, &major, &minor))
    {
      cu->producer_is_gxx_lt_4_6 = major < 4 || (major == 4 && minor < 6);
      cu->producer_is_gcc_lt_4_3 = major < 4 || (major == 4 && minor < 3);
    }
  else if (producer_is_icc (cu->producer, &major, &minor))
    {
      cu->producer_is_icc = true;
      cu->producer_is_icc_lt_14 = major < 14;
    }
  else if (startswith (cu->producer, "CodeWarrior S12/L-ISA"))
    cu->producer_is_codewarrior = true;
  else
    {
      /* For other non-GCC compilers, expect their behavior is DWARF version
	 compliant.  */
    }

  cu->checked_producer = true;
}

/* Check for GCC PR debug/45124 fix which is not present in any G++ version up
   to 4.5.any while it is present already in G++ 4.6.0 - the PR has been fixed
   during 4.6.0 experimental.  */

static bool
producer_is_gxx_lt_4_6 (struct dwarf2_cu *cu)
{
  if (!cu->checked_producer)
    check_producer (cu);

  return cu->producer_is_gxx_lt_4_6;
}


/* Codewarrior (at least as of version 5.0.40) generates dwarf line information
   with incorrect is_stmt attributes.  */

static bool
producer_is_codewarrior (struct dwarf2_cu *cu)
{
  if (!cu->checked_producer)
    check_producer (cu);

  return cu->producer_is_codewarrior;
}

/* Return the default accessibility type if it is not overridden by
   DW_AT_accessibility.  */

static enum dwarf_access_attribute
dwarf2_default_access_attribute (struct die_info *die, struct dwarf2_cu *cu)
{
  if (cu->header.version < 3 || producer_is_gxx_lt_4_6 (cu))
    {
      /* The default DWARF 2 accessibility for members is public, the default
	 accessibility for inheritance is private.  */

      if (die->tag != DW_TAG_inheritance)
	return DW_ACCESS_public;
      else
	return DW_ACCESS_private;
    }
  else
    {
      /* DWARF 3+ defines the default accessibility a different way.  The same
	 rules apply now for DW_TAG_inheritance as for the members and it only
	 depends on the container kind.  */

      if (die->parent->tag == DW_TAG_class_type)
	return DW_ACCESS_private;
      else
	return DW_ACCESS_public;
    }
}

/* Look for DW_AT_data_member_location.  Set *OFFSET to the byte
   offset.  If the attribute was not found return 0, otherwise return
   1.  If it was found but could not properly be handled, set *OFFSET
   to 0.  */

static int
handle_data_member_location (struct die_info *die, struct dwarf2_cu *cu,
			     LONGEST *offset)
{
  struct attribute *attr;

  attr = dwarf2_attr (die, DW_AT_data_member_location, cu);
  if (attr != NULL)
    {
      *offset = 0;

      /* Note that we do not check for a section offset first here.
	 This is because DW_AT_data_member_location is new in DWARF 4,
	 so if we see it, we can assume that a constant form is really
	 a constant and not a section offset.  */
      if (attr_form_is_constant (attr))
	*offset = dwarf2_get_attr_constant_value (attr, 0);
      else if (attr_form_is_section_offset (attr))
	dwarf2_complex_location_expr_complaint ();
      else if (attr_form_is_block (attr))
	*offset = decode_locdesc (DW_BLOCK (attr), cu);
      else
	dwarf2_complex_location_expr_complaint ();

      return 1;
    }

  return 0;
}

/* Add an aggregate field to the field list.  */

static void
dwarf2_add_field (struct field_info *fip, struct die_info *die,
		  struct dwarf2_cu *cu)
{
  struct objfile *objfile = cu->per_cu->dwarf2_per_objfile->objfile;
  struct gdbarch *gdbarch = get_objfile_arch (objfile);
  struct nextfield *new_field;
  struct attribute *attr;
  struct field *fp;
  const char *fieldname = "";

  if (die->tag == DW_TAG_inheritance)
    {
      fip->baseclasses.emplace_back ();
      new_field = &fip->baseclasses.back ();
    }
  else
    {
      fip->fields.emplace_back ();
      new_field = &fip->fields.back ();
    }

  fip->nfields++;

  attr = dwarf2_attr (die, DW_AT_accessibility, cu);
  if (attr != nullptr)
    new_field->accessibility = DW_UNSND (attr);
  else
    new_field->accessibility = dwarf2_default_access_attribute (die, cu);
  if (new_field->accessibility != DW_ACCESS_public)
    fip->non_public_fields = 1;

  attr = dwarf2_attr (die, DW_AT_virtuality, cu);
  if (attr != nullptr)
    new_field->virtuality = DW_UNSND (attr);
  else
    new_field->virtuality = DW_VIRTUALITY_none;

  fp = &new_field->field;

  if (die->tag == DW_TAG_member && ! die_is_declaration (die, cu))
    {
      LONGEST offset;

      /* Data member other than a C++ static data member.  */

      /* Get type of field.  */
      fp->type = die_type (die, cu);

      SET_FIELD_BITPOS (*fp, 0);

      /* Get bit size of field (zero if none).  */
      attr = dwarf2_attr (die, DW_AT_bit_size, cu);
      if (attr != nullptr)
	{
	  FIELD_BITSIZE (*fp) = DW_UNSND (attr);
	}
      else
	{
	  FIELD_BITSIZE (*fp) = 0;
	}

      /* Get bit offset of field.  */
      if (handle_data_member_location (die, cu, &offset))
	SET_FIELD_BITPOS (*fp, offset * bits_per_byte);
      attr = dwarf2_attr (die, DW_AT_bit_offset, cu);
      if (attr != nullptr)
	{
	  if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
	    {
	      /* For big endian bits, the DW_AT_bit_offset gives the
               	 additional bit offset from the MSB of the containing
               	 anonymous object to the MSB of the field.  We don't
               	 have to do anything special since we don't need to
               	 know the size of the anonymous object.  */
	      SET_FIELD_BITPOS (*fp, FIELD_BITPOS (*fp) + DW_UNSND (attr));
	    }
	  else
	    {
	      /* For little endian bits, compute the bit offset to the
               	 MSB of the anonymous object, subtract off the number of
               	 bits from the MSB of the field to the MSB of the
               	 object, and then subtract off the number of bits of
               	 the field itself.  The result is the bit offset of
               	 the LSB of the field.  */
	      int anonymous_size;
	      int bit_offset = DW_UNSND (attr);

	      attr = dwarf2_attr (die, DW_AT_byte_size, cu);
	      if (attr != nullptr)
		{
		  /* The size of the anonymous object containing
		     the bit field is explicit, so use the
		     indicated size (in bytes).  */
		  anonymous_size = DW_UNSND (attr);
		}
	      else
		{
		  /* The size of the anonymous object containing
		     the bit field must be inferred from the type
		     attribute of the data member containing the
		     bit field.  */
		  anonymous_size = TYPE_LENGTH (fp->type);
		}
	      SET_FIELD_BITPOS (*fp,
				(FIELD_BITPOS (*fp)
				 + anonymous_size * bits_per_byte
				 - bit_offset - FIELD_BITSIZE (*fp)));
	    }
	}
      attr = dwarf2_attr (die, DW_AT_data_bit_offset, cu);
      if (attr != NULL)
	SET_FIELD_BITPOS (*fp, (FIELD_BITPOS (*fp)
				+ dwarf2_get_attr_constant_value (attr, 0)));

      /* Get name of field.  */
      fieldname = dwarf2_name (die, cu);
      if (fieldname == NULL)
	fieldname = "";