compiler/elf_writer_quick.h - platform/art - Git at Google

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef ART_COMPILER_ELF_WRITER_QUICK_H_
 #define ART_COMPILER_ELF_WRITER_QUICK_H_

 #include "elf_utils.h"
 #include "elf_writer.h"
 #include "instruction_set.h"

 namespace art {

 class ElfWriterQuick FINAL : public ElfWriter {
  public:
   // Write an ELF file. Returns true on success, false on failure.
   static bool Create(File* file,
                      OatWriter* oat_writer,
                      const std::vector<const DexFile*>& dex_files,
                      const std::string& android_root,
                      bool is_host,
                      const CompilerDriver& driver)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  protected:
   bool Write(OatWriter* oat_writer,
              const std::vector<const DexFile*>& dex_files,
              const std::string& android_root,
              bool is_host)
       OVERRIDE
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  private:
   ElfWriterQuick(const CompilerDriver& driver, File* elf_file)
     : ElfWriter(driver, elf_file) {}
   ~ElfWriterQuick() {}

   class ElfBuilder;
   void AddDebugSymbols(ElfBuilder& builder,
                        OatWriter* oat_writer,
                        bool debug);
   void ReservePatchSpace(std::vector<uint8_t>* buffer, bool debug);

   class ElfSectionBuilder {
    public:
     ElfSectionBuilder(const std::string& sec_name, Elf32_Word type, Elf32_Word flags,
                       const ElfSectionBuilder *link, Elf32_Word info, Elf32_Word align,
                       Elf32_Word entsize)
         : name_(sec_name), link_(link) {
       memset(&section_, 0, sizeof(section_));
       section_.sh_type = type;
       section_.sh_flags = flags;
       section_.sh_info = info;
       section_.sh_addralign = align;
       section_.sh_entsize = entsize;
     }

     virtual ~ElfSectionBuilder() {}

     Elf32_Shdr section_;
     Elf32_Word section_index_ = 0;

    protected:
     const std::string name_;
     const ElfSectionBuilder* link_;

     Elf32_Word GetLink() {
       return (link_) ? link_->section_index_ : 0;
     }

    private:
     friend class ElfBuilder;
   };

   class ElfDynamicBuilder : public ElfSectionBuilder {
    public:
     void AddDynamicTag(Elf32_Sword tag, Elf32_Word d_un);
     void AddDynamicTag(Elf32_Sword tag, Elf32_Word offset, ElfSectionBuilder* section);

     ElfDynamicBuilder(const std::string& sec_name, ElfSectionBuilder *link)
         : ElfSectionBuilder(sec_name, SHT_DYNAMIC, SHF_ALLOC | SHF_ALLOC, link,
                             0, kPageSize, sizeof(Elf32_Dyn)) {}
     ~ElfDynamicBuilder() {}

    protected:
     struct ElfDynamicState {
       ElfSectionBuilder* section_;
       Elf32_Sword tag_;
       Elf32_Word off_;
     };
     std::vector<ElfDynamicState> dynamics_;
     Elf32_Word GetSize() {
       // Add 1 for the DT_NULL, 1 for DT_STRSZ, and 1 for DT_SONAME. All of
       // these must be added when we actually put the file together because
       // their values are very dependent on state.
       return dynamics_.size() + 3;
     }

     // Create the actual dynamic vector. strsz should be the size of the .dynstr
     // table and soname_off should be the offset of the soname in .dynstr.
     // Since niether can be found prior to final layout we will wait until here
     // to add them.
     std::vector<Elf32_Dyn> GetDynamics(Elf32_Word strsz, Elf32_Word soname_off);

    private:
     friend class ElfBuilder;
   };

   class ElfRawSectionBuilder : public ElfSectionBuilder {
    public:
     ElfRawSectionBuilder(const std::string& sec_name, Elf32_Word type, Elf32_Word flags,
                          const ElfSectionBuilder* link, Elf32_Word info, Elf32_Word align,
                          Elf32_Word entsize)
         : ElfSectionBuilder(sec_name, type, flags, link, info, align, entsize) {}
     ~ElfRawSectionBuilder() {}
     std::vector<uint8_t>* GetBuffer() { return &buf_; }
     void SetBuffer(std::vector<uint8_t> buf) { buf_ = buf; }

    protected:
     std::vector<uint8_t> buf_;

    private:
     friend class ElfBuilder;
   };

   class ElfOatSectionBuilder : public ElfSectionBuilder {
    public:
     ElfOatSectionBuilder(const std::string& sec_name, Elf32_Word size, Elf32_Word offset,
                          Elf32_Word type, Elf32_Word flags)
         : ElfSectionBuilder(sec_name, type, flags, NULL, 0, kPageSize, 0),
           offset_(offset), size_(size) {}
     ~ElfOatSectionBuilder() {}

    protected:
     // Offset of the content within the file.
     Elf32_Word offset_;
     // Size of the content within the file.
     Elf32_Word size_;

    private:
     friend class ElfBuilder;
   };

   class ElfSymtabBuilder : public ElfSectionBuilder {
    public:
     // Add a symbol with given name to this symtab. The symbol refers to
     // 'relative_addr' within the given section and has the given attributes.
     void AddSymbol(const std::string& name,
                    const ElfSectionBuilder* section,
                    Elf32_Addr addr,
                    bool is_relative,
                    Elf32_Word size,
                    uint8_t binding,
                    uint8_t type,
                    uint8_t other = 0);

     ElfSymtabBuilder(const std::string& sec_name, Elf32_Word type,
                      const std::string& str_name, Elf32_Word str_type, bool alloc)
         : ElfSectionBuilder(sec_name, type, ((alloc) ? SHF_ALLOC : 0U), &strtab_, 0,
                             sizeof(Elf32_Word), sizeof(Elf32_Sym)),
           str_name_(str_name), str_type_(str_type),
           strtab_(str_name, str_type, ((alloc) ? SHF_ALLOC : 0U), NULL, 0, 1, 1) {}
     ~ElfSymtabBuilder() {}

    protected:
     std::vector<Elf32_Word> GenerateHashContents();
     std::string GenerateStrtab();
     std::vector<Elf32_Sym> GenerateSymtab();

     Elf32_Word GetSize() {
       // 1 is for the implicit NULL symbol.
       return symbols_.size() + 1;
     }

     struct ElfSymbolState {
       const std::string name_;
       const ElfSectionBuilder* section_;
       Elf32_Addr addr_;
       Elf32_Word size_;
       bool is_relative_;
       uint8_t info_;
       uint8_t other_;
       // Used during Write() to temporarially hold name index in the strtab.
       Elf32_Word name_idx_;
     };

     // Information for the strsym for dynstr sections.
     const std::string str_name_;
     Elf32_Word str_type_;
     // The symbols in the same order they will be in the symbol table.
     std::vector<ElfSymbolState> symbols_;
     ElfSectionBuilder strtab_;

    private:
     friend class ElfBuilder;
   };

   class ElfBuilder FINAL {
    public:
     ElfBuilder(OatWriter* oat_writer,
                File* elf_file,
                InstructionSet isa,
                Elf32_Word rodata_relative_offset,
                Elf32_Word rodata_size,
                Elf32_Word text_relative_offset,
                Elf32_Word text_size,
                const bool add_symbols,
                bool debug = false)
         : oat_writer_(oat_writer),
           elf_file_(elf_file),
           add_symbols_(add_symbols),
           debug_logging_(debug),
           text_builder_(".text", text_size, text_relative_offset, SHT_PROGBITS,
                         SHF_ALLOC | SHF_EXECINSTR),
           rodata_builder_(".rodata", rodata_size, rodata_relative_offset,
                           SHT_PROGBITS, SHF_ALLOC),
           dynsym_builder_(".dynsym", SHT_DYNSYM, ".dynstr", SHT_STRTAB, true),
           symtab_builder_(".symtab", SHT_SYMTAB, ".strtab", SHT_STRTAB, false),
           hash_builder_(".hash", SHT_HASH, SHF_ALLOC, &dynsym_builder_, 0,
                         sizeof(Elf32_Word), sizeof(Elf32_Word)),
           dynamic_builder_(".dynamic", &dynsym_builder_),
           shstrtab_builder_(".shstrtab", SHT_STRTAB, 0, NULL, 0, 1, 1) {
       SetupEhdr();
       SetupDynamic();
       SetupRequiredSymbols();
       SetISA(isa);
     }
     ~ElfBuilder() {}

     bool Write();

     // Adds the given raw section to the builder. This will copy it. The caller
     // is responsible for deallocating their copy.
     void RegisterRawSection(ElfRawSectionBuilder bld) {
       other_builders_.push_back(bld);
     }

    private:
     OatWriter* oat_writer_;
     File* elf_file_;
     const bool add_symbols_;
     const bool debug_logging_;

     bool fatal_error_ = false;

     Elf32_Ehdr elf_header_;

    public:
     ElfOatSectionBuilder text_builder_;
     ElfOatSectionBuilder rodata_builder_;
     ElfSymtabBuilder dynsym_builder_;
     ElfSymtabBuilder symtab_builder_;
     ElfSectionBuilder hash_builder_;
     ElfDynamicBuilder dynamic_builder_;
     ElfSectionBuilder shstrtab_builder_;
     std::vector<ElfRawSectionBuilder> other_builders_;

    private:
     void SetISA(InstructionSet isa);
     void SetupEhdr();

     // Sets up a bunch of the required Dynamic Section entries.
     // Namely it will initialize all the mandatory ones that it can.
     // Specifically:
     // DT_HASH
     // DT_STRTAB
     // DT_SYMTAB
     // DT_SYMENT
     //
     // Some such as DT_SONAME, DT_STRSZ and DT_NULL will be put in later.
     void SetupDynamic();

     // Sets up the basic dynamic symbols that are needed, namely all those we
     // can know already.
     //
     // Specifically adds:
     // oatdata
     // oatexec
     // oatlastword
     void SetupRequiredSymbols();
     void AssignSectionStr(ElfSectionBuilder *builder, std::string* strtab);
     struct ElfFilePiece {
       ElfFilePiece(const std::string& name, Elf32_Word offset, const void* data, Elf32_Word size)
           : dbg_name_(name), offset_(offset), data_(data), size_(size) {}
       ~ElfFilePiece() {}

       const std::string& dbg_name_;
       Elf32_Word offset_;
       const void *data_;
       Elf32_Word size_;
       static bool Compare(ElfFilePiece a, ElfFilePiece b) {
         return a.offset_ < b.offset_;
       }
     };

     // Write each of the pieces out to the file.
     bool WriteOutFile(const std::vector<ElfFilePiece>& pieces);
     bool IncludingDebugSymbols() { return add_symbols_ && symtab_builder_.GetSize() > 1; }
   };

   /*
    * @brief Generate the DWARF debug_info and debug_abbrev sections
    * @param oat_writer The Oat file Writer.
    * @param dbg_info Compilation unit information.
    * @param dbg_abbrev Abbreviations used to generate dbg_info.
    * @param dbg_str Debug strings.
    */
   void FillInCFIInformation(OatWriter* oat_writer, std::vector<uint8_t>* dbg_info,
                             std::vector<uint8_t>* dbg_abbrev, std::vector<uint8_t>* dbg_str);

   DISALLOW_IMPLICIT_CONSTRUCTORS(ElfWriterQuick);
 };

 }  // namespace art

 #endif  // ART_COMPILER_ELF_WRITER_QUICK_H_
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef ART_COMPILER_ELF_WRITER_QUICK_H_
	#define ART_COMPILER_ELF_WRITER_QUICK_H_

	#include "elf_utils.h"
	#include "elf_writer.h"
	#include "instruction_set.h"

	namespace art {

	class ElfWriterQuick FINAL : public ElfWriter {
	public:
	// Write an ELF file. Returns true on success, false on failure.
	static bool Create(File* file,
	OatWriter* oat_writer,
	const std::vector<const DexFile*>& dex_files,
	const std::string& android_root,
	bool is_host,
	const CompilerDriver& driver)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	protected:
	bool Write(OatWriter* oat_writer,
	const std::vector<const DexFile*>& dex_files,
	const std::string& android_root,
	bool is_host)
	OVERRIDE
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	private:
	ElfWriterQuick(const CompilerDriver& driver, File* elf_file)
	: ElfWriter(driver, elf_file) {}
	~ElfWriterQuick() {}

	class ElfBuilder;
	void AddDebugSymbols(ElfBuilder& builder,
	OatWriter* oat_writer,
	bool debug);
	void ReservePatchSpace(std::vector<uint8_t>* buffer, bool debug);

	class ElfSectionBuilder {
	public:
	ElfSectionBuilder(const std::string& sec_name, Elf32_Word type, Elf32_Word flags,
	const ElfSectionBuilder *link, Elf32_Word info, Elf32_Word align,
	Elf32_Word entsize)
	: name_(sec_name), link_(link) {
	memset(&section_, 0, sizeof(section_));
	section_.sh_type = type;
	section_.sh_flags = flags;
	section_.sh_info = info;
	section_.sh_addralign = align;
	section_.sh_entsize = entsize;
	}

	virtual ~ElfSectionBuilder() {}

	Elf32_Shdr section_;
	Elf32_Word section_index_ = 0;

	protected:
	const std::string name_;
	const ElfSectionBuilder* link_;

	Elf32_Word GetLink() {
	return (link_) ? link_->section_index_ : 0;
	}

	private:
	friend class ElfBuilder;
	};

	class ElfDynamicBuilder : public ElfSectionBuilder {
	public:
	void AddDynamicTag(Elf32_Sword tag, Elf32_Word d_un);
	void AddDynamicTag(Elf32_Sword tag, Elf32_Word offset, ElfSectionBuilder* section);

	ElfDynamicBuilder(const std::string& sec_name, ElfSectionBuilder *link)
	: ElfSectionBuilder(sec_name, SHT_DYNAMIC, SHF_ALLOC \| SHF_ALLOC, link,
	0, kPageSize, sizeof(Elf32_Dyn)) {}
	~ElfDynamicBuilder() {}

	protected:
	struct ElfDynamicState {
	ElfSectionBuilder* section_;
	Elf32_Sword tag_;
	Elf32_Word off_;
	};
	std::vector<ElfDynamicState> dynamics_;
	Elf32_Word GetSize() {
	// Add 1 for the DT_NULL, 1 for DT_STRSZ, and 1 for DT_SONAME. All of
	// these must be added when we actually put the file together because
	// their values are very dependent on state.
	return dynamics_.size() + 3;
	}

	// Create the actual dynamic vector. strsz should be the size of the .dynstr
	// table and soname_off should be the offset of the soname in .dynstr.
	// Since niether can be found prior to final layout we will wait until here
	// to add them.
	std::vector<Elf32_Dyn> GetDynamics(Elf32_Word strsz, Elf32_Word soname_off);

	private:
	friend class ElfBuilder;
	};

	class ElfRawSectionBuilder : public ElfSectionBuilder {
	public:
	ElfRawSectionBuilder(const std::string& sec_name, Elf32_Word type, Elf32_Word flags,
	const ElfSectionBuilder* link, Elf32_Word info, Elf32_Word align,
	Elf32_Word entsize)
	: ElfSectionBuilder(sec_name, type, flags, link, info, align, entsize) {}
	~ElfRawSectionBuilder() {}
	std::vector<uint8_t>* GetBuffer() { return &buf_; }
	void SetBuffer(std::vector<uint8_t> buf) { buf_ = buf; }

	protected:
	std::vector<uint8_t> buf_;

	private:
	friend class ElfBuilder;
	};

	class ElfOatSectionBuilder : public ElfSectionBuilder {
	public:
	ElfOatSectionBuilder(const std::string& sec_name, Elf32_Word size, Elf32_Word offset,
	Elf32_Word type, Elf32_Word flags)
	: ElfSectionBuilder(sec_name, type, flags, NULL, 0, kPageSize, 0),
	offset_(offset), size_(size) {}
	~ElfOatSectionBuilder() {}

	protected:
	// Offset of the content within the file.
	Elf32_Word offset_;
	// Size of the content within the file.
	Elf32_Word size_;

	private:
	friend class ElfBuilder;
	};

	class ElfSymtabBuilder : public ElfSectionBuilder {
	public:
	// Add a symbol with given name to this symtab. The symbol refers to
	// 'relative_addr' within the given section and has the given attributes.
	void AddSymbol(const std::string& name,
	const ElfSectionBuilder* section,
	Elf32_Addr addr,
	bool is_relative,
	Elf32_Word size,
	uint8_t binding,
	uint8_t type,
	uint8_t other = 0);

	ElfSymtabBuilder(const std::string& sec_name, Elf32_Word type,
	const std::string& str_name, Elf32_Word str_type, bool alloc)
	: ElfSectionBuilder(sec_name, type, ((alloc) ? SHF_ALLOC : 0U), &strtab_, 0,
	sizeof(Elf32_Word), sizeof(Elf32_Sym)),
	str_name_(str_name), str_type_(str_type),
	strtab_(str_name, str_type, ((alloc) ? SHF_ALLOC : 0U), NULL, 0, 1, 1) {}
	~ElfSymtabBuilder() {}

	protected:
	std::vector<Elf32_Word> GenerateHashContents();
	std::string GenerateStrtab();
	std::vector<Elf32_Sym> GenerateSymtab();

	Elf32_Word GetSize() {
	// 1 is for the implicit NULL symbol.
	return symbols_.size() + 1;
	}

	struct ElfSymbolState {
	const std::string name_;
	const ElfSectionBuilder* section_;
	Elf32_Addr addr_;
	Elf32_Word size_;
	bool is_relative_;
	uint8_t info_;
	uint8_t other_;
	// Used during Write() to temporarially hold name index in the strtab.
	Elf32_Word name_idx_;
	};

	// Information for the strsym for dynstr sections.
	const std::string str_name_;
	Elf32_Word str_type_;
	// The symbols in the same order they will be in the symbol table.
	std::vector<ElfSymbolState> symbols_;
	ElfSectionBuilder strtab_;

	private:
	friend class ElfBuilder;
	};

	class ElfBuilder FINAL {
	public:
	ElfBuilder(OatWriter* oat_writer,
	File* elf_file,
	InstructionSet isa,
	Elf32_Word rodata_relative_offset,
	Elf32_Word rodata_size,
	Elf32_Word text_relative_offset,
	Elf32_Word text_size,
	const bool add_symbols,
	bool debug = false)
	: oat_writer_(oat_writer),
	elf_file_(elf_file),
	add_symbols_(add_symbols),
	debug_logging_(debug),
	text_builder_(".text", text_size, text_relative_offset, SHT_PROGBITS,
	SHF_ALLOC \| SHF_EXECINSTR),
	rodata_builder_(".rodata", rodata_size, rodata_relative_offset,
	SHT_PROGBITS, SHF_ALLOC),
	dynsym_builder_(".dynsym", SHT_DYNSYM, ".dynstr", SHT_STRTAB, true),
	symtab_builder_(".symtab", SHT_SYMTAB, ".strtab", SHT_STRTAB, false),
	hash_builder_(".hash", SHT_HASH, SHF_ALLOC, &dynsym_builder_, 0,
	sizeof(Elf32_Word), sizeof(Elf32_Word)),
	dynamic_builder_(".dynamic", &dynsym_builder_),
	shstrtab_builder_(".shstrtab", SHT_STRTAB, 0, NULL, 0, 1, 1) {
	SetupEhdr();
	SetupDynamic();
	SetupRequiredSymbols();
	SetISA(isa);
	}
	~ElfBuilder() {}

	bool Write();

	// Adds the given raw section to the builder. This will copy it. The caller
	// is responsible for deallocating their copy.
	void RegisterRawSection(ElfRawSectionBuilder bld) {
	other_builders_.push_back(bld);
	}

	private:
	OatWriter* oat_writer_;
	File* elf_file_;
	const bool add_symbols_;
	const bool debug_logging_;

	bool fatal_error_ = false;

	Elf32_Ehdr elf_header_;

	public:
	ElfOatSectionBuilder text_builder_;
	ElfOatSectionBuilder rodata_builder_;
	ElfSymtabBuilder dynsym_builder_;
	ElfSymtabBuilder symtab_builder_;
	ElfSectionBuilder hash_builder_;
	ElfDynamicBuilder dynamic_builder_;
	ElfSectionBuilder shstrtab_builder_;
	std::vector<ElfRawSectionBuilder> other_builders_;

	private:
	void SetISA(InstructionSet isa);
	void SetupEhdr();

	// Sets up a bunch of the required Dynamic Section entries.
	// Namely it will initialize all the mandatory ones that it can.
	// Specifically:
	// DT_HASH
	// DT_STRTAB
	// DT_SYMTAB
	// DT_SYMENT
	//
	// Some such as DT_SONAME, DT_STRSZ and DT_NULL will be put in later.
	void SetupDynamic();

	// Sets up the basic dynamic symbols that are needed, namely all those we
	// can know already.
	//
	// Specifically adds:
	// oatdata
	// oatexec
	// oatlastword
	void SetupRequiredSymbols();
	void AssignSectionStr(ElfSectionBuilder builder, std::string strtab);
	struct ElfFilePiece {
	ElfFilePiece(const std::string& name, Elf32_Word offset, const void* data, Elf32_Word size)
	: dbg_name_(name), offset_(offset), data_(data), size_(size) {}
	~ElfFilePiece() {}

	const std::string& dbg_name_;
	Elf32_Word offset_;
	const void *data_;
	Elf32_Word size_;
	static bool Compare(ElfFilePiece a, ElfFilePiece b) {
	return a.offset_ < b.offset_;
	}
	};

	// Write each of the pieces out to the file.
	bool WriteOutFile(const std::vector<ElfFilePiece>& pieces);
	bool IncludingDebugSymbols() { return add_symbols_ && symtab_builder_.GetSize() > 1; }
	};

	/*
	* @brief Generate the DWARF debug_info and debug_abbrev sections
	* @param oat_writer The Oat file Writer.
	* @param dbg_info Compilation unit information.
	* @param dbg_abbrev Abbreviations used to generate dbg_info.
	* @param dbg_str Debug strings.
	*/
	void FillInCFIInformation(OatWriter* oat_writer, std::vector<uint8_t>* dbg_info,
	std::vector<uint8_t>* dbg_abbrev, std::vector<uint8_t>* dbg_str);

	DISALLOW_IMPLICIT_CONSTRUCTORS(ElfWriterQuick);
	};

	} // namespace art

	#endif // ART_COMPILER_ELF_WRITER_QUICK_H_