hotspot/src/share/vm/code/codeCache.cpp

/*
 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "code/codeBlob.hpp"
#include "code/codeCache.hpp"
#include "code/compiledIC.hpp"
#include "code/dependencies.hpp"
#include "code/icBuffer.hpp"
#include "code/nmethod.hpp"
#include "code/pcDesc.hpp"
#include "compiler/compileBroker.hpp"
#include "gc_implementation/shared/markSweep.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/gcLocker.hpp"
#include "memory/iterator.hpp"
#include "memory/resourceArea.hpp"
#include "oops/method.hpp"
#include "oops/objArrayOop.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/arguments.hpp"
#include "runtime/icache.hpp"
#include "runtime/java.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/sweeper.hpp"
#include "runtime/compilationPolicy.hpp"
#include "services/memoryService.hpp"
#include "trace/tracing.hpp"
#include "utilities/xmlstream.hpp"
#ifdef COMPILER1
#include "c1/c1_Compilation.hpp"
#include "c1/c1_Compiler.hpp"
#endif
#ifdef COMPILER2
#include "opto/c2compiler.hpp"
#include "opto/compile.hpp"
#include "opto/node.hpp"
#endif

// Helper class for printing in CodeCache
class CodeBlob_sizes {
 private:
  int count;
  int total_size;
  int header_size;
  int code_size;
  int stub_size;
  int relocation_size;
  int scopes_oop_size;
  int scopes_metadata_size;
  int scopes_data_size;
  int scopes_pcs_size;

 public:
  CodeBlob_sizes() {
    count            = 0;
    total_size       = 0;
    header_size      = 0;
    code_size        = 0;
    stub_size        = 0;
    relocation_size  = 0;
    scopes_oop_size  = 0;
    scopes_metadata_size  = 0;
    scopes_data_size = 0;
    scopes_pcs_size  = 0;
  }

  int total()                                    { return total_size; }
  bool is_empty()                                { return count == 0; }

  void print(const char* title) {
    tty->print_cr(" #%d %s = %dK (hdr %d%%,  loc %d%%, code %d%%, stub %d%%, [oops %d%%, metadata %d%%, data %d%%, pcs %d%%])",
                  count,
                  title,
                  (int)(total() / K),
                  header_size             * 100 / total_size,
                  relocation_size         * 100 / total_size,
                  code_size               * 100 / total_size,
                  stub_size               * 100 / total_size,
                  scopes_oop_size         * 100 / total_size,
                  scopes_metadata_size    * 100 / total_size,
                  scopes_data_size        * 100 / total_size,
                  scopes_pcs_size         * 100 / total_size);
  }

  void add(CodeBlob* cb) {
    count++;
    total_size       += cb->size();
    header_size      += cb->header_size();
    relocation_size  += cb->relocation_size();
    if (cb->is_nmethod()) {
      nmethod* nm = cb->as_nmethod_or_null();
      code_size        += nm->insts_size();
      stub_size        += nm->stub_size();

      scopes_oop_size  += nm->oops_size();
      scopes_metadata_size  += nm->metadata_size();
      scopes_data_size += nm->scopes_data_size();
      scopes_pcs_size  += nm->scopes_pcs_size();
    } else {
      code_size        += cb->code_size();
    }
  }
};

// Iterate over all CodeHeaps
#define FOR_ALL_HEAPS(heap) for (GrowableArrayIterator<CodeHeap*> heap = _heaps->begin(); heap != _heaps->end(); ++heap)
// Iterate over all CodeBlobs (cb) on the given CodeHeap
#define FOR_ALL_BLOBS(cb, heap) for (CodeBlob* cb = first_blob(heap); cb != NULL; cb = next_blob(heap, cb))

address CodeCache::_low_bound = 0;
address CodeCache::_high_bound = 0;
int CodeCache::_number_of_blobs = 0;
int CodeCache::_number_of_adapters = 0;
int CodeCache::_number_of_nmethods = 0;
int CodeCache::_number_of_nmethods_with_dependencies = 0;
bool CodeCache::_needs_cache_clean = false;
nmethod* CodeCache::_scavenge_root_nmethods = NULL;
int CodeCache::_codemem_full_count = 0;

// Initialize array of CodeHeaps
GrowableArray<CodeHeap*>* CodeCache::_heaps = new(ResourceObj::C_HEAP, mtCode) GrowableArray<CodeHeap*> (CodeBlobType::All, true);

void CodeCache::initialize_heaps() {
  // Determine size of compiler buffers
  size_t code_buffers_size = 0;
#ifdef COMPILER1
  // C1 temporary code buffers (see Compiler::init_buffer_blob())
  const int c1_count = CompilationPolicy::policy()->compiler_count(CompLevel_simple);
  code_buffers_size += c1_count * Compiler::code_buffer_size();
#endif
#ifdef COMPILER2
  // C2 scratch buffers (see Compile::init_scratch_buffer_blob())
  const int c2_count = CompilationPolicy::policy()->compiler_count(CompLevel_full_optimization);
  // Initial size of constant table (this may be increased if a compiled method needs more space)
  code_buffers_size += c2_count * C2Compiler::initial_code_buffer_size();
#endif

  // Calculate default CodeHeap sizes if not set by user
  if (!FLAG_IS_CMDLINE(NonNMethodCodeHeapSize) && !FLAG_IS_CMDLINE(ProfiledCodeHeapSize)
      && !FLAG_IS_CMDLINE(NonProfiledCodeHeapSize)) {
    // Increase default NonNMethodCodeHeapSize to account for compiler buffers
    FLAG_SET_ERGO(uintx, NonNMethodCodeHeapSize, NonNMethodCodeHeapSize + code_buffers_size);

    // Check if we have enough space for the non-nmethod code heap
    if (ReservedCodeCacheSize > NonNMethodCodeHeapSize) {
      // Use the default value for NonNMethodCodeHeapSize and one half of the
      // remaining size for non-profiled methods and one half for profiled methods
      size_t remaining_size = ReservedCodeCacheSize - NonNMethodCodeHeapSize;
      size_t profiled_size = remaining_size / 2;
      size_t non_profiled_size = remaining_size - profiled_size;
      FLAG_SET_ERGO(uintx, ProfiledCodeHeapSize, profiled_size);
      FLAG_SET_ERGO(uintx, NonProfiledCodeHeapSize, non_profiled_size);
    } else {
      // Use all space for the non-nmethod heap and set other heaps to minimal size
      FLAG_SET_ERGO(uintx, NonNMethodCodeHeapSize, ReservedCodeCacheSize - os::vm_page_size() * 2);
      FLAG_SET_ERGO(uintx, ProfiledCodeHeapSize, os::vm_page_size());
      FLAG_SET_ERGO(uintx, NonProfiledCodeHeapSize, os::vm_page_size());
    }
  }

  // We do not need the profiled CodeHeap, use all space for the non-profiled CodeHeap
  if(!heap_available(CodeBlobType::MethodProfiled)) {
    FLAG_SET_ERGO(uintx, NonProfiledCodeHeapSize, NonProfiledCodeHeapSize + ProfiledCodeHeapSize);
    FLAG_SET_ERGO(uintx, ProfiledCodeHeapSize, 0);
  }
  // We do not need the non-profiled CodeHeap, use all space for the non-nmethod CodeHeap
  if(!heap_available(CodeBlobType::MethodNonProfiled)) {
    FLAG_SET_ERGO(uintx, NonNMethodCodeHeapSize, NonNMethodCodeHeapSize + NonProfiledCodeHeapSize);
    FLAG_SET_ERGO(uintx, NonProfiledCodeHeapSize, 0);
  }

  // Make sure we have enough space for VM internal code
  uint min_code_cache_size = CodeCacheMinimumUseSpace DEBUG_ONLY(* 3);
  if (NonNMethodCodeHeapSize < (min_code_cache_size + code_buffers_size)) {
    vm_exit_during_initialization("Not enough space in non-nmethod code heap to run VM.");
  }
  guarantee(NonProfiledCodeHeapSize + ProfiledCodeHeapSize + NonNMethodCodeHeapSize <= ReservedCodeCacheSize, "Size check");

  // Align reserved sizes of CodeHeaps
  size_t non_method_size   = ReservedCodeSpace::allocation_align_size_up(NonNMethodCodeHeapSize);
  size_t profiled_size     = ReservedCodeSpace::allocation_align_size_up(ProfiledCodeHeapSize);
  size_t non_profiled_size = ReservedCodeSpace::allocation_align_size_up(NonProfiledCodeHeapSize);

  // Compute initial sizes of CodeHeaps
  size_t init_non_method_size   = MIN2(InitialCodeCacheSize, non_method_size);
  size_t init_profiled_size     = MIN2(InitialCodeCacheSize, profiled_size);
  size_t init_non_profiled_size = MIN2(InitialCodeCacheSize, non_profiled_size);

  // Reserve one continuous chunk of memory for CodeHeaps and split it into
  // parts for the individual heaps. The memory layout looks like this:
  // ---------- high -----------
  //    Non-profiled nmethods
  //      Profiled nmethods
  //         Non-nmethods
  // ---------- low ------------
  ReservedCodeSpace rs = reserve_heap_memory(non_profiled_size + profiled_size + non_method_size);
  ReservedSpace non_method_space    = rs.first_part(non_method_size);
  ReservedSpace rest                = rs.last_part(non_method_size);
  ReservedSpace profiled_space      = rest.first_part(profiled_size);
  ReservedSpace non_profiled_space  = rest.last_part(profiled_size);

  // Non-nmethods (stubs, adapters, ...)
  add_heap(non_method_space, "CodeHeap 'non-nmethods'", init_non_method_size, CodeBlobType::NonNMethod);
  // Tier 2 and tier 3 (profiled) methods
  add_heap(profiled_space, "CodeHeap 'profiled nmethods'", init_profiled_size, CodeBlobType::MethodProfiled);
  // Tier 1 and tier 4 (non-profiled) methods and native methods
  add_heap(non_profiled_space, "CodeHeap 'non-profiled nmethods'", init_non_profiled_size, CodeBlobType::MethodNonProfiled);
}

ReservedCodeSpace CodeCache::reserve_heap_memory(size_t size) {
  // Determine alignment
  const size_t page_size = os::can_execute_large_page_memory() ?
          MIN2(os::page_size_for_region(InitialCodeCacheSize, 8),
               os::page_size_for_region(size, 8)) :
          os::vm_page_size();
  const size_t granularity = os::vm_allocation_granularity();
  const size_t r_align = MAX2(page_size, granularity);
  const size_t r_size = align_size_up(size, r_align);
  const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 :
    MAX2(page_size, granularity);

  ReservedCodeSpace rs(r_size, rs_align, rs_align > 0);

  // Initialize bounds
  _low_bound = (address)rs.base();
  _high_bound = _low_bound + rs.size();

  return rs;
}

bool CodeCache::heap_available(int code_blob_type) {
  if (!SegmentedCodeCache) {
    // No segmentation: use a single code heap
    return (code_blob_type == CodeBlobType::All);
  } else if (Arguments::mode() == Arguments::_int) {
    // Interpreter only: we don't need any method code heaps
    return (code_blob_type == CodeBlobType::NonNMethod);
  } else if (TieredCompilation && (TieredStopAtLevel > CompLevel_simple)) {
    // Tiered compilation: use all code heaps
    return (code_blob_type < CodeBlobType::All);
  } else {
    // No TieredCompilation: we only need the non-nmethod and non-profiled code heap
    return (code_blob_type == CodeBlobType::NonNMethod) ||
           (code_blob_type == CodeBlobType::MethodNonProfiled);
  }
}

const char* CodeCache::get_code_heap_flag_name(int code_blob_type) {
  switch(code_blob_type) {
  case CodeBlobType::NonNMethod:
    return "NonNMethodCodeHeapSize";
    break;
  case CodeBlobType::MethodNonProfiled:
    return "NonProfiledCodeHeapSize";
    break;
  case CodeBlobType::MethodProfiled:
    return "ProfiledCodeHeapSize";
    break;
  }
  ShouldNotReachHere();
  return NULL;
}

void CodeCache::add_heap(ReservedSpace rs, const char* name, size_t size_initial, int code_blob_type) {
  // Check if heap is needed
  if (!heap_available(code_blob_type)) {
    return;
  }

  // Create CodeHeap
  CodeHeap* heap = new CodeHeap(name, code_blob_type);
  _heaps->append(heap);

  // Reserve Space
  size_initial = round_to(size_initial, os::vm_page_size());

  if (!heap->reserve(rs, size_initial, CodeCacheSegmentSize)) {
    vm_exit_during_initialization("Could not reserve enough space for code cache");
  }

  // Register the CodeHeap
  MemoryService::add_code_heap_memory_pool(heap, name);
}

CodeHeap* CodeCache::get_code_heap(const CodeBlob* cb) {
  assert(cb != NULL, "CodeBlob is null");
  FOR_ALL_HEAPS(heap) {
    if ((*heap)->contains(cb)) {
      return *heap;
    }
  }
  ShouldNotReachHere();
  return NULL;
}

CodeHeap* CodeCache::get_code_heap(int code_blob_type) {
  FOR_ALL_HEAPS(heap) {
    if ((*heap)->accepts(code_blob_type)) {
      return *heap;
    }
  }
  return NULL;
}

CodeBlob* CodeCache::first_blob(CodeHeap* heap) {
  assert_locked_or_safepoint(CodeCache_lock);
  assert(heap != NULL, "heap is null");
  return (CodeBlob*)heap->first();
}

CodeBlob* CodeCache::first_blob(int code_blob_type) {
  if (heap_available(code_blob_type)) {
    return first_blob(get_code_heap(code_blob_type));
  } else {
    return NULL;
  }
}

CodeBlob* CodeCache::next_blob(CodeHeap* heap, CodeBlob* cb) {
  assert_locked_or_safepoint(CodeCache_lock);
  assert(heap != NULL, "heap is null");
  return (CodeBlob*)heap->next(cb);
}

CodeBlob* CodeCache::next_blob(CodeBlob* cb) {
  return next_blob(get_code_heap(cb), cb);
}

/**
 * Do not seize the CodeCache lock here--if the caller has not
 * already done so, we are going to lose bigtime, since the code
 * cache will contain a garbage CodeBlob until the caller can
 * run the constructor for the CodeBlob subclass he is busy
 * instantiating.
 */
CodeBlob* CodeCache::allocate(int size, int code_blob_type) {
  // Possibly wakes up the sweeper thread.
  NMethodSweeper::notify(code_blob_type);
  assert_locked_or_safepoint(CodeCache_lock);
  assert(size > 0, err_msg_res("Code cache allocation request must be > 0 but is %d", size));
  if (size <= 0) {
    return NULL;
  }
  CodeBlob* cb = NULL;

  // Get CodeHeap for the given CodeBlobType
  CodeHeap* heap = get_code_heap(code_blob_type);
  assert(heap != NULL, "heap is null");

  while (true) {
    cb = (CodeBlob*)heap->allocate(size);
    if (cb != NULL) break;
    if (!heap->expand_by(CodeCacheExpansionSize)) {
      // Expansion failed
      if (SegmentedCodeCache && (code_blob_type == CodeBlobType::NonNMethod)) {
        // Fallback solution: Store non-nmethod code in the non-profiled code heap.
        // Note that at in the sweeper, we check the reverse_free_ratio of the non-profiled
        // code heap and force stack scanning if less than 10% if the code heap are free.
        return allocate(size, CodeBlobType::MethodNonProfiled);
      }
      MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
      CompileBroker::handle_full_code_cache(code_blob_type);
      return NULL;
    }
    if (PrintCodeCacheExtension) {
      ResourceMark rm;
      if (SegmentedCodeCache) {
        tty->print("%s", heap->name());
      } else {
        tty->print("CodeCache");
      }
      tty->print_cr(" extended to [" INTPTR_FORMAT ", " INTPTR_FORMAT "] (" SSIZE_FORMAT " bytes)",
                    (intptr_t)heap->low_boundary(), (intptr_t)heap->high(),
                    (address)heap->high() - (address)heap->low_boundary());
    }
  }
  print_trace("allocation", cb, size);
  _number_of_blobs++;
  return cb;
}

void CodeCache::free(CodeBlob* cb) {
  assert_locked_or_safepoint(CodeCache_lock);

  print_trace("free", cb);
  if (cb->is_nmethod()) {
    _number_of_nmethods--;
    if (((nmethod *)cb)->has_dependencies()) {
      _number_of_nmethods_with_dependencies--;
    }
  }
  if (cb->is_adapter_blob()) {
    _number_of_adapters--;
  }
  _number_of_blobs--;

  // Get heap for given CodeBlob and deallocate
  get_code_heap(cb)->deallocate(cb);

  assert(_number_of_blobs >= 0, "sanity check");
}

void CodeCache::commit(CodeBlob* cb) {
  // this is called by nmethod::nmethod, which must already own CodeCache_lock
  assert_locked_or_safepoint(CodeCache_lock);
  if (cb->is_nmethod()) {
    _number_of_nmethods++;
    if (((nmethod *)cb)->has_dependencies()) {
      _number_of_nmethods_with_dependencies++;
    }
  }
  if (cb->is_adapter_blob()) {
    _number_of_adapters++;
  }

  // flush the hardware I-cache
  ICache::invalidate_range(cb->content_begin(), cb->content_size());
}

bool CodeCache::contains(void *p) {
  // It should be ok to call contains without holding a lock
  FOR_ALL_HEAPS(heap) {
    if ((*heap)->contains(p)) {
      return true;
    }
  }
  return false;
}

// This method is safe to call without holding the CodeCache_lock, as long as a dead CodeBlob is not
// looked up (i.e., one that has been marked for deletion). It only depends on the _segmap to contain
// valid indices, which it will always do, as long as the CodeBlob is not in the process of being recycled.
CodeBlob* CodeCache::find_blob(void* start) {
  CodeBlob* result = find_blob_unsafe(start);
  // We could potentially look up non_entrant methods
  guarantee(result == NULL || !result->is_zombie() || result->is_locked_by_vm() || is_error_reported(), "unsafe access to zombie method");
  return result;
}

// Lookup that does not fail if you lookup a zombie method (if you call this, be sure to know
// what you are doing)
CodeBlob* CodeCache::find_blob_unsafe(void* start) {
  // NMT can walk the stack before code cache is created
  if (_heaps == NULL || _heaps->is_empty()) return NULL;

  FOR_ALL_HEAPS(heap) {
    CodeBlob* result = (CodeBlob*) (*heap)->find_start(start);
    if (result != NULL && result->blob_contains((address)start)) {
      return result;
    }
  }
  return NULL;
}

nmethod* CodeCache::find_nmethod(void* start) {
  CodeBlob* cb = find_blob(start);
  assert(cb->is_nmethod(), "did not find an nmethod");
  return (nmethod*)cb;
}

void CodeCache::blobs_do(void f(CodeBlob* nm)) {
  assert_locked_or_safepoint(CodeCache_lock);
  FOR_ALL_HEAPS(heap) {
    FOR_ALL_BLOBS(cb, *heap) {
      f(cb);
    }
  }
}

void CodeCache::nmethods_do(void f(nmethod* nm)) {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next()) {
    f(iter.method());
  }
}

void CodeCache::alive_nmethods_do(void f(nmethod* nm)) {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next_alive()) {
    f(iter.method());
  }
}

int CodeCache::alignment_unit() {
  return (int)_heaps->first()->alignment_unit();
}

int CodeCache::alignment_offset() {
  return (int)_heaps->first()->alignment_offset();
}

// Mark nmethods for unloading if they contain otherwise unreachable oops.
void CodeCache::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next_alive()) {
    iter.method()->do_unloading(is_alive, unloading_occurred);
  }
}

void CodeCache::blobs_do(CodeBlobClosure* f) {
  assert_locked_or_safepoint(CodeCache_lock);
  FOR_ALL_HEAPS(heap) {
    FOR_ALL_BLOBS(cb, *heap) {
      if (cb->is_alive()) {
        f->do_code_blob(cb);

#ifdef ASSERT
        if (cb->is_nmethod())
        ((nmethod*)cb)->verify_scavenge_root_oops();
#endif //ASSERT
      }
    }
  }
}

// Walk the list of methods which might contain non-perm oops.
void CodeCache::scavenge_root_nmethods_do(CodeBlobClosure* f) {
  assert_locked_or_safepoint(CodeCache_lock);

  if (UseG1GC) {
    return;
  }

  debug_only(mark_scavenge_root_nmethods());

  for (nmethod* cur = scavenge_root_nmethods(); cur != NULL; cur = cur->scavenge_root_link()) {
    debug_only(cur->clear_scavenge_root_marked());
    assert(cur->scavenge_root_not_marked(), "");
    assert(cur->on_scavenge_root_list(), "else shouldn't be on this list");

    bool is_live = (!cur->is_zombie() && !cur->is_unloaded());
#ifndef PRODUCT
    if (TraceScavenge) {
      cur->print_on(tty, is_live ? "scavenge root" : "dead scavenge root"); tty->cr();
    }
#endif //PRODUCT
    if (is_live) {
      // Perform cur->oops_do(f), maybe just once per nmethod.
      f->do_code_blob(cur);
    }
  }

  // Check for stray marks.
  debug_only(verify_perm_nmethods(NULL));
}

void CodeCache::add_scavenge_root_nmethod(nmethod* nm) {
  assert_locked_or_safepoint(CodeCache_lock);

  if (UseG1GC) {
    return;
  }

  nm->set_on_scavenge_root_list();
  nm->set_scavenge_root_link(_scavenge_root_nmethods);
  set_scavenge_root_nmethods(nm);
  print_trace("add_scavenge_root", nm);
}

void CodeCache::drop_scavenge_root_nmethod(nmethod* nm) {
  assert_locked_or_safepoint(CodeCache_lock);

  if (UseG1GC) {
    return;
  }

  print_trace("drop_scavenge_root", nm);
  nmethod* last = NULL;
  nmethod* cur = scavenge_root_nmethods();
  while (cur != NULL) {
    nmethod* next = cur->scavenge_root_link();
    if (cur == nm) {
      if (last != NULL)
            last->set_scavenge_root_link(next);
      else  set_scavenge_root_nmethods(next);
      nm->set_scavenge_root_link(NULL);
      nm->clear_on_scavenge_root_list();
      return;
    }
    last = cur;
    cur = next;
  }
  assert(false, "should have been on list");
}

void CodeCache::prune_scavenge_root_nmethods() {
  assert_locked_or_safepoint(CodeCache_lock);

  if (UseG1GC) {
    return;
  }

  debug_only(mark_scavenge_root_nmethods());

  nmethod* last = NULL;
  nmethod* cur = scavenge_root_nmethods();
  while (cur != NULL) {
    nmethod* next = cur->scavenge_root_link();
    debug_only(cur->clear_scavenge_root_marked());
    assert(cur->scavenge_root_not_marked(), "");
    assert(cur->on_scavenge_root_list(), "else shouldn't be on this list");

    if (!cur->is_zombie() && !cur->is_unloaded()
        && cur->detect_scavenge_root_oops()) {
      // Keep it.  Advance 'last' to prevent deletion.
      last = cur;
    } else {
      // Prune it from the list, so we don't have to look at it any more.
      print_trace("prune_scavenge_root", cur);
      cur->set_scavenge_root_link(NULL);
      cur->clear_on_scavenge_root_list();
      if (last != NULL)
            last->set_scavenge_root_link(next);
      else  set_scavenge_root_nmethods(next);
    }
    cur = next;
  }

  // Check for stray marks.
  debug_only(verify_perm_nmethods(NULL));
}

#ifndef PRODUCT
void CodeCache::asserted_non_scavengable_nmethods_do(CodeBlobClosure* f) {
  if (UseG1GC) {
    return;
  }

  // While we are here, verify the integrity of the list.
  mark_scavenge_root_nmethods();
  for (nmethod* cur = scavenge_root_nmethods(); cur != NULL; cur = cur->scavenge_root_link()) {
    assert(cur->on_scavenge_root_list(), "else shouldn't be on this list");
    cur->clear_scavenge_root_marked();
  }
  verify_perm_nmethods(f);
}

// Temporarily mark nmethods that are claimed to be on the non-perm list.
void CodeCache::mark_scavenge_root_nmethods() {
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    assert(nm->scavenge_root_not_marked(), "clean state");
    if (nm->on_scavenge_root_list())
      nm->set_scavenge_root_marked();
  }
}

// If the closure is given, run it on the unlisted nmethods.
// Also make sure that the effects of mark_scavenge_root_nmethods is gone.
void CodeCache::verify_perm_nmethods(CodeBlobClosure* f_or_null) {
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    bool call_f = (f_or_null != NULL);
    assert(nm->scavenge_root_not_marked(), "must be already processed");
    if (nm->on_scavenge_root_list())
      call_f = false;  // don't show this one to the client
    nm->verify_scavenge_root_oops();
    if (call_f)  f_or_null->do_code_blob(nm);
  }
}
#endif //PRODUCT

void CodeCache::verify_clean_inline_caches() {
#ifdef ASSERT
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    assert(!nm->is_unloaded(), "Tautology");
    nm->verify_clean_inline_caches();
    nm->verify();
  }
#endif
}

void CodeCache::verify_icholder_relocations() {
#ifdef ASSERT
  // make sure that we aren't leaking icholders
  int count = 0;
  FOR_ALL_HEAPS(heap) {
    FOR_ALL_BLOBS(cb, *heap) {
      if (cb->is_nmethod()) {
        nmethod* nm = (nmethod*)cb;
        count += nm->verify_icholder_relocations();
      }
    }
  }

  assert(count + InlineCacheBuffer::pending_icholder_count() + CompiledICHolder::live_not_claimed_count() ==
         CompiledICHolder::live_count(), "must agree");
#endif
}

void CodeCache::gc_prologue() {
}

void CodeCache::gc_epilogue() {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    assert(!nm->is_unloaded(), "Tautology");
    if (needs_cache_clean()) {
      nm->cleanup_inline_caches();
    }
    DEBUG_ONLY(nm->verify());
    DEBUG_ONLY(nm->verify_oop_relocations());
  }
  set_needs_cache_clean(false);
  prune_scavenge_root_nmethods();

  verify_icholder_relocations();
}

void CodeCache::verify_oops() {
  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  VerifyOopClosure voc;
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    nm->oops_do(&voc);
    nm->verify_oop_relocations();
  }
}

size_t CodeCache::capacity() {
  size_t cap = 0;
  FOR_ALL_HEAPS(heap) {
    cap += (*heap)->capacity();
  }
  return cap;
}

size_t CodeCache::unallocated_capacity(int code_blob_type) {
  CodeHeap* heap = get_code_heap(code_blob_type);
  return (heap != NULL) ? heap->unallocated_capacity() : 0;
}

size_t CodeCache::unallocated_capacity() {
  size_t unallocated_cap = 0;
  FOR_ALL_HEAPS(heap) {
    unallocated_cap += (*heap)->unallocated_capacity();
  }
  return unallocated_cap;
}

size_t CodeCache::max_capacity() {
  size_t max_cap = 0;
  FOR_ALL_HEAPS(heap) {
    max_cap += (*heap)->max_capacity();
  }
  return max_cap;
}

/**
 * Returns the reverse free ratio. E.g., if 25% (1/4) of the code heap
 * is free, reverse_free_ratio() returns 4.
 */
double CodeCache::reverse_free_ratio(int code_blob_type) {
  CodeHeap* heap = get_code_heap(code_blob_type);
  if (heap == NULL) {
    return 0;
  }

  double unallocated_capacity = MAX2((double)heap->unallocated_capacity(), 1.0); // Avoid division by 0;
  double max_capacity = (double)heap->max_capacity();
  double result = max_capacity / unallocated_capacity;
  assert (max_capacity >= unallocated_capacity, "Must be");
  assert (result >= 1.0, err_msg_res("reverse_free_ratio must be at least 1. It is %f", result));
  return result;
}

size_t CodeCache::bytes_allocated_in_freelists() {
  size_t allocated_bytes = 0;
  FOR_ALL_HEAPS(heap) {
    allocated_bytes += (*heap)->allocated_in_freelist();
  }
  return allocated_bytes;
}

int CodeCache::allocated_segments() {
  int number_of_segments = 0;
  FOR_ALL_HEAPS(heap) {
    number_of_segments += (*heap)->allocated_segments();
  }
  return number_of_segments;
}

size_t CodeCache::freelists_length() {
  size_t length = 0;
  FOR_ALL_HEAPS(heap) {
    length += (*heap)->freelist_length();
  }
  return length;
}

void icache_init();

void CodeCache::initialize() {
  assert(CodeCacheSegmentSize >= (uintx)CodeEntryAlignment, "CodeCacheSegmentSize must be large enough to align entry points");
#ifdef COMPILER2
  assert(CodeCacheSegmentSize >= (uintx)OptoLoopAlignment,  "CodeCacheSegmentSize must be large enough to align inner loops");
#endif
  assert(CodeCacheSegmentSize >= sizeof(jdouble),    "CodeCacheSegmentSize must be large enough to align constants");
  // This was originally just a check of the alignment, causing failure, instead, round
  // the code cache to the page size.  In particular, Solaris is moving to a larger
  // default page size.
  CodeCacheExpansionSize = round_to(CodeCacheExpansionSize, os::vm_page_size());

  if (SegmentedCodeCache) {
    // Use multiple code heaps
    initialize_heaps();
  } else {
    // Use a single code heap
    ReservedCodeSpace rs = reserve_heap_memory(ReservedCodeCacheSize);
    add_heap(rs, "CodeCache", InitialCodeCacheSize, CodeBlobType::All);
  }

  // Initialize ICache flush mechanism
  // This service is needed for os::register_code_area
  icache_init();

  // Give OS a chance to register generated code area.
  // This is used on Windows 64 bit platforms to register
  // Structured Exception Handlers for our generated code.
  os::register_code_area((char*)low_bound(), (char*)high_bound());
}

void codeCache_init() {
  CodeCache::initialize();
}

//------------------------------------------------------------------------------------------------

int CodeCache::number_of_nmethods_with_dependencies() {
  return _number_of_nmethods_with_dependencies;
}

void CodeCache::clear_inline_caches() {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next_alive()) {
    iter.method()->clear_inline_caches();
  }
}

// Keeps track of time spent for checking dependencies
NOT_PRODUCT(static elapsedTimer dependentCheckTime;)

int CodeCache::mark_for_deoptimization(DepChange& changes) {
  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  int number_of_marked_CodeBlobs = 0;

  // search the hierarchy looking for nmethods which are affected by the loading of this class

  // then search the interfaces this class implements looking for nmethods
  // which might be dependent of the fact that an interface only had one
  // implementor.
  // nmethod::check_all_dependencies works only correctly, if no safepoint
  // can happen
  No_Safepoint_Verifier nsv;
  for (DepChange::ContextStream str(changes, nsv); str.next(); ) {
    Klass* d = str.klass();
    number_of_marked_CodeBlobs += InstanceKlass::cast(d)->mark_dependent_nmethods(changes);
  }

#ifndef PRODUCT
  if (VerifyDependencies) {
    // Object pointers are used as unique identifiers for dependency arguments. This
    // is only possible if no safepoint, i.e., GC occurs during the verification code.
    dependentCheckTime.start();
    nmethod::check_all_dependencies(changes);
    dependentCheckTime.stop();
  }
#endif

  return number_of_marked_CodeBlobs;
}


#ifdef HOTSWAP
int CodeCache::mark_for_evol_deoptimization(instanceKlassHandle dependee) {
  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  int number_of_marked_CodeBlobs = 0;

  // Deoptimize all methods of the evolving class itself
  Array<Method*>* old_methods = dependee->methods();
  for (int i = 0; i < old_methods->length(); i++) {
    ResourceMark rm;
    Method* old_method = old_methods->at(i);
    nmethod *nm = old_method->code();
    if (nm != NULL) {
      nm->mark_for_deoptimization();
      number_of_marked_CodeBlobs++;
    }
  }

  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    if (nm->is_marked_for_deoptimization()) {
      // ...Already marked in the previous pass; don't count it again.
    } else if (nm->is_evol_dependent_on(dependee())) {
      ResourceMark rm;
      nm->mark_for_deoptimization();
      number_of_marked_CodeBlobs++;
    } else  {
      // flush caches in case they refer to a redefined Method*
      nm->clear_inline_caches();
    }
  }

  return number_of_marked_CodeBlobs;
}
#endif // HOTSWAP


// Deoptimize all methods
void CodeCache::mark_all_nmethods_for_deoptimization() {
  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    if (!nm->method()->is_method_handle_intrinsic()) {
      nm->mark_for_deoptimization();
    }
  }
}

int CodeCache::mark_for_deoptimization(Method* dependee) {
  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
  int number_of_marked_CodeBlobs = 0;

  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    if (nm->is_dependent_on_method(dependee)) {
      ResourceMark rm;
      nm->mark_for_deoptimization();
      number_of_marked_CodeBlobs++;
    }
  }

  return number_of_marked_CodeBlobs;
}

void CodeCache::make_marked_nmethods_zombies() {
  assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    if (nm->is_marked_for_deoptimization()) {

      // If the nmethod has already been made non-entrant and it can be converted
      // then zombie it now. Otherwise make it non-entrant and it will eventually
      // be zombied when it is no longer seen on the stack. Note that the nmethod
      // might be "entrant" and not on the stack and so could be zombied immediately
      // but we can't tell because we don't track it on stack until it becomes
      // non-entrant.

      if (nm->is_not_entrant() && nm->can_not_entrant_be_converted()) {
        nm->make_zombie();
      } else {
        nm->make_not_entrant();
      }
    }
  }
}

void CodeCache::make_marked_nmethods_not_entrant() {
  assert_locked_or_safepoint(CodeCache_lock);
  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    if (nm->is_marked_for_deoptimization()) {
      nm->make_not_entrant();
    }
  }
}

void CodeCache::verify() {
  assert_locked_or_safepoint(CodeCache_lock);
  FOR_ALL_HEAPS(heap) {
    (*heap)->verify();
    FOR_ALL_BLOBS(cb, *heap) {
      if (cb->is_alive()) {
        cb->verify();
      }
    }
  }
}

// A CodeHeap is full. Print out warning and report event.
void CodeCache::report_codemem_full(int code_blob_type, bool print) {
  // Get nmethod heap for the given CodeBlobType and build CodeCacheFull event
  CodeHeap* heap = get_code_heap(code_blob_type);
  assert(heap != NULL, "heap is null");

  if (!heap->was_full() || print) {
    // Not yet reported for this heap, report
    heap->report_full();
    if (SegmentedCodeCache) {
      warning("%s is full. Compiler has been disabled.", get_code_heap_name(code_blob_type));
      warning("Try increasing the code heap size using -XX:%s=", get_code_heap_flag_name(code_blob_type));
    } else {
      warning("CodeCache is full. Compiler has been disabled.");
      warning("Try increasing the code cache size using -XX:ReservedCodeCacheSize=");
    }
    ResourceMark rm;
    stringStream s;
    // Dump code cache  into a buffer before locking the tty,
    {
      MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
      print_summary(&s);
    }
    ttyLocker ttyl;
    tty->print("%s", s.as_string());
  }

  _codemem_full_count++;
  EventCodeCacheFull event;
  if (event.should_commit()) {
    event.set_codeBlobType((u1)code_blob_type);
    event.set_startAddress((u8)heap->low_boundary());
    event.set_commitedTopAddress((u8)heap->high());
    event.set_reservedTopAddress((u8)heap->high_boundary());
    event.set_entryCount(nof_blobs());
    event.set_methodCount(nof_nmethods());
    event.set_adaptorCount(nof_adapters());
    event.set_unallocatedCapacity(heap->unallocated_capacity()/K);
    event.set_fullCount(_codemem_full_count);
    event.commit();
  }
}

void CodeCache::print_memory_overhead() {
  size_t wasted_bytes = 0;
  FOR_ALL_HEAPS(heap) {
      CodeHeap* curr_heap = *heap;
      for (CodeBlob* cb = (CodeBlob*)curr_heap->first(); cb != NULL; cb = (CodeBlob*)curr_heap->next(cb)) {
        HeapBlock* heap_block = ((HeapBlock*)cb) - 1;
        wasted_bytes += heap_block->length() * CodeCacheSegmentSize - cb->size();
      }
  }
  // Print bytes that are allocated in the freelist
  ttyLocker ttl;
  tty->print_cr("Number of elements in freelist: " SSIZE_FORMAT,       freelists_length());
  tty->print_cr("Allocated in freelist:          " SSIZE_FORMAT "kB",  bytes_allocated_in_freelists()/K);
  tty->print_cr("Unused bytes in CodeBlobs:      " SSIZE_FORMAT "kB",  (wasted_bytes/K));
  tty->print_cr("Segment map size:               " SSIZE_FORMAT "kB",  allocated_segments()/K); // 1 byte per segment
}

//------------------------------------------------------------------------------------------------
// Non-product version

#ifndef PRODUCT

void CodeCache::print_trace(const char* event, CodeBlob* cb, int size) {
  if (PrintCodeCache2) {  // Need to add a new flag
    ResourceMark rm;
    if (size == 0)  size = cb->size();
    tty->print_cr("CodeCache %s:  addr: " INTPTR_FORMAT ", size: 0x%x", event, p2i(cb), size);
  }
}

void CodeCache::print_internals() {
  int nmethodCount = 0;
  int runtimeStubCount = 0;
  int adapterCount = 0;
  int deoptimizationStubCount = 0;
  int uncommonTrapStubCount = 0;
  int bufferBlobCount = 0;
  int total = 0;
  int nmethodAlive = 0;
  int nmethodNotEntrant = 0;
  int nmethodZombie = 0;
  int nmethodUnloaded = 0;
  int nmethodJava = 0;
  int nmethodNative = 0;
  int max_nm_size = 0;
  ResourceMark rm;

  int i = 0;
  FOR_ALL_HEAPS(heap) {
    if (SegmentedCodeCache && Verbose) {
      tty->print_cr("-- %s --", (*heap)->name());
    }
    FOR_ALL_BLOBS(cb, *heap) {
      total++;
      if (cb->is_nmethod()) {
        nmethod* nm = (nmethod*)cb;

        if (Verbose && nm->method() != NULL) {
          ResourceMark rm;
          char *method_name = nm->method()->name_and_sig_as_C_string();
          tty->print("%s", method_name);
          if(nm->is_alive()) { tty->print_cr(" alive"); }
          if(nm->is_not_entrant()) { tty->print_cr(" not-entrant"); }
          if(nm->is_zombie()) { tty->print_cr(" zombie"); }
        }

        nmethodCount++;

        if(nm->is_alive()) { nmethodAlive++; }
        if(nm->is_not_entrant()) { nmethodNotEntrant++; }
        if(nm->is_zombie()) { nmethodZombie++; }
        if(nm->is_unloaded()) { nmethodUnloaded++; }
        if(nm->method() != NULL && nm->is_native_method()) { nmethodNative++; }

        if(nm->method() != NULL && nm->is_java_method()) {
          nmethodJava++;
          max_nm_size = MAX2(max_nm_size, nm->size());
        }
      } else if (cb->is_runtime_stub()) {
        runtimeStubCount++;
      } else if (cb->is_deoptimization_stub()) {
        deoptimizationStubCount++;
      } else if (cb->is_uncommon_trap_stub()) {
        uncommonTrapStubCount++;
      } else if (cb->is_adapter_blob()) {
        adapterCount++;
      } else if (cb->is_buffer_blob()) {
        bufferBlobCount++;
      }
    }
  }

  int bucketSize = 512;
  int bucketLimit = max_nm_size / bucketSize + 1;
  int *buckets = NEW_C_HEAP_ARRAY(int, bucketLimit, mtCode);
  memset(buckets, 0, sizeof(int) * bucketLimit);

  NMethodIterator iter;
  while(iter.next()) {
    nmethod* nm = iter.method();
    if(nm->method() != NULL && nm->is_java_method()) {
      buckets[nm->size() / bucketSize]++;
    }
  }

  tty->print_cr("Code Cache Entries (total of %d)",total);
  tty->print_cr("-------------------------------------------------");
  tty->print_cr("nmethods: %d",nmethodCount);
  tty->print_cr("\talive: %d",nmethodAlive);
  tty->print_cr("\tnot_entrant: %d",nmethodNotEntrant);
  tty->print_cr("\tzombie: %d",nmethodZombie);
  tty->print_cr("\tunloaded: %d",nmethodUnloaded);
  tty->print_cr("\tjava: %d",nmethodJava);
  tty->print_cr("\tnative: %d",nmethodNative);
  tty->print_cr("runtime_stubs: %d",runtimeStubCount);
  tty->print_cr("adapters: %d",adapterCount);
  tty->print_cr("buffer blobs: %d",bufferBlobCount);
  tty->print_cr("deoptimization_stubs: %d",deoptimizationStubCount);
  tty->print_cr("uncommon_traps: %d",uncommonTrapStubCount);
  tty->print_cr("\nnmethod size distribution (non-zombie java)");
  tty->print_cr("-------------------------------------------------");

  for(int i=0; i<bucketLimit; i++) {
    if(buckets[i] != 0) {
      tty->print("%d - %d bytes",i*bucketSize,(i+1)*bucketSize);
      tty->fill_to(40);
      tty->print_cr("%d",buckets[i]);
    }
  }

  FREE_C_HEAP_ARRAY(int, buckets, mtCode);
  print_memory_overhead();
}

#endif // !PRODUCT

void CodeCache::print() {
  print_summary(tty);

#ifndef PRODUCT
  if (!Verbose) return;

  CodeBlob_sizes live;
  CodeBlob_sizes dead;

  FOR_ALL_HEAPS(heap) {
    FOR_ALL_BLOBS(cb, *heap) {
      if (!cb->is_alive()) {
        dead.add(cb);
      } else {
        live.add(cb);
      }
    }
  }

  tty->print_cr("CodeCache:");
  tty->print_cr("nmethod dependency checking time %fs", dependentCheckTime.seconds());

  if (!live.is_empty()) {
    live.print("live");
  }
  if (!dead.is_empty()) {
    dead.print("dead");
  }

  if (WizardMode) {
     // print the oop_map usage
    int code_size = 0;
    int number_of_blobs = 0;
    int number_of_oop_maps = 0;
    int map_size = 0;
    FOR_ALL_HEAPS(heap) {
      FOR_ALL_BLOBS(cb, *heap) {
        if (cb->is_alive()) {
          number_of_blobs++;
          code_size += cb->code_size();
          OopMapSet* set = cb->oop_maps();
          if (set != NULL) {
            number_of_oop_maps += set->size();
            map_size           += set->heap_size();
          }
        }
      }
    }
    tty->print_cr("OopMaps");
    tty->print_cr("  #blobs    = %d", number_of_blobs);
    tty->print_cr("  code size = %d", code_size);
    tty->print_cr("  #oop_maps = %d", number_of_oop_maps);
    tty->print_cr("  map size  = %d", map_size);
  }

#endif // !PRODUCT
}

void CodeCache::print_summary(outputStream* st, bool detailed) {
  FOR_ALL_HEAPS(heap_iterator) {
    CodeHeap* heap = (*heap_iterator);
    size_t total = (heap->high_boundary() - heap->low_boundary());
    if (SegmentedCodeCache) {
      st->print("%s:", heap->name());
    } else {
      st->print("CodeCache:");
    }
    st->print_cr(" size=" SIZE_FORMAT "Kb used=" SIZE_FORMAT
                 "Kb max_used=" SIZE_FORMAT "Kb free=" SIZE_FORMAT "Kb",
                 total/K, (total - heap->unallocated_capacity())/K,
                 heap->max_allocated_capacity()/K, heap->unallocated_capacity()/K);

    if (detailed) {
      st->print_cr(" bounds [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT "]",
                   p2i(heap->low_boundary()),
                   p2i(heap->high()),
                   p2i(heap->high_boundary()));
    }
  }

  if (detailed) {
    st->print_cr(" total_blobs=" UINT32_FORMAT " nmethods=" UINT32_FORMAT
                       " adapters=" UINT32_FORMAT,
                       nof_blobs(), nof_nmethods(), nof_adapters());
    st->print_cr(" compilation: %s", CompileBroker::should_compile_new_jobs() ?
                 "enabled" : Arguments::mode() == Arguments::_int ?
                 "disabled (interpreter mode)" :
                 "disabled (not enough contiguous free space left)");
  }
}

void CodeCache::print_codelist(outputStream* st) {
  assert_locked_or_safepoint(CodeCache_lock);

  NMethodIterator iter;
  while(iter.next_alive()) {
    nmethod* nm = iter.method();
    ResourceMark rm;
    char *method_name = nm->method()->name_and_sig_as_C_string();
    st->print_cr("%d %d %s ["INTPTR_FORMAT", "INTPTR_FORMAT" - "INTPTR_FORMAT"]",
                 nm->compile_id(), nm->comp_level(), method_name, (intptr_t)nm->header_begin(),
                 (intptr_t)nm->code_begin(), (intptr_t)nm->code_end());
  }
}

void CodeCache::print_layout(outputStream* st) {
  assert_locked_or_safepoint(CodeCache_lock);
  ResourceMark rm;

  print_summary(st, true);
}

void CodeCache::log_state(outputStream* st) {
  st->print(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'"
            " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
            nof_blobs(), nof_nmethods(), nof_adapters(),
            unallocated_capacity());
}