import full versions of dependency libraries!

1 files changed, 2599 insertions, 0 deletions

diff --git a/deps/v8/src/spaces.cc b/deps/v8/src/spaces.cc
new file mode 100644
index 0000000000..ea40d52116
--- /dev/null
+++ b/deps/v8/src/spaces.cc
@@ -0,0 +1,2599 @@
+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "macro-assembler.h"
+#include "mark-compact.h"
+#include "platform.h"
+
+namespace v8 { namespace internal {
+
+// For contiguous spaces, top should be in the space (or at the end) and limit
+// should be the end of the space.
+#define ASSERT_SEMISPACE_ALLOCATION_INFO(info, space) \
+  ASSERT((space).low() <= (info).top                 \
+         && (info).top <= (space).high()             \
+         && (info).limit == (space).high())
+
+
+// ----------------------------------------------------------------------------
+// HeapObjectIterator
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space) {
+  Initialize(space->bottom(), space->top(), NULL);
+}
+
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space,
+                                       HeapObjectCallback size_func) {
+  Initialize(space->bottom(), space->top(), size_func);
+}
+
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start) {
+  Initialize(start, space->top(), NULL);
+}
+
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start,
+                                       HeapObjectCallback size_func) {
+  Initialize(start, space->top(), size_func);
+}
+
+
+void HeapObjectIterator::Initialize(Address cur, Address end,
+                                    HeapObjectCallback size_f) {
+  cur_addr_ = cur;
+  end_addr_ = end;
+  end_page_ = Page::FromAllocationTop(end);
+  size_func_ = size_f;
+  Page* p = Page::FromAllocationTop(cur_addr_);
+  cur_limit_ = (p == end_page_) ? end_addr_ : p->AllocationTop();
+
+#ifdef DEBUG
+  Verify();
+#endif
+}
+
+
+bool HeapObjectIterator::HasNextInNextPage() {
+  if (cur_addr_ == end_addr_) return false;
+
+  Page* cur_page = Page::FromAllocationTop(cur_addr_);
+  cur_page = cur_page->next_page();
+  ASSERT(cur_page->is_valid());
+
+  cur_addr_ = cur_page->ObjectAreaStart();
+  cur_limit_ = (cur_page == end_page_) ? end_addr_ : cur_page->AllocationTop();
+
+  ASSERT(cur_addr_ < cur_limit_);
+#ifdef DEBUG
+  Verify();
+#endif
+  return true;
+}
+
+
+#ifdef DEBUG
+void HeapObjectIterator::Verify() {
+  Page* p = Page::FromAllocationTop(cur_addr_);
+  ASSERT(p == Page::FromAllocationTop(cur_limit_));
+  ASSERT(p->Offset(cur_addr_) <= p->Offset(cur_limit_));
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// PageIterator
+
+PageIterator::PageIterator(PagedSpace* space, Mode mode) {
+  cur_page_ = space->first_page_;
+  switch (mode) {
+    case PAGES_IN_USE:
+      stop_page_ = space->AllocationTopPage()->next_page();
+      break;
+    case PAGES_USED_BY_MC:
+      stop_page_ = space->MCRelocationTopPage()->next_page();
+      break;
+    case ALL_PAGES:
+      stop_page_ = Page::FromAddress(NULL);
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+// -----------------------------------------------------------------------------
+// Page
+
+#ifdef DEBUG
+Page::RSetState Page::rset_state_ = Page::IN_USE;
+#endif
+
+// -----------------------------------------------------------------------------
+// MemoryAllocator
+//
+int MemoryAllocator::capacity_   = 0;
+int MemoryAllocator::size_       = 0;
+
+VirtualMemory* MemoryAllocator::initial_chunk_ = NULL;
+
+// 270 is an estimate based on the static default heap size of a pair of 256K
+// semispaces and a 64M old generation.
+const int kEstimatedNumberOfChunks = 270;
+List<MemoryAllocator::ChunkInfo> MemoryAllocator::chunks_(
+    kEstimatedNumberOfChunks);
+List<int> MemoryAllocator::free_chunk_ids_(kEstimatedNumberOfChunks);
+int MemoryAllocator::max_nof_chunks_ = 0;
+int MemoryAllocator::top_ = 0;
+
+
+void MemoryAllocator::Push(int free_chunk_id) {
+  ASSERT(max_nof_chunks_ > 0);
+  ASSERT(top_ < max_nof_chunks_);
+  free_chunk_ids_[top_++] = free_chunk_id;
+}
+
+
+int MemoryAllocator::Pop() {
+  ASSERT(top_ > 0);
+  return free_chunk_ids_[--top_];
+}
+
+
+bool MemoryAllocator::Setup(int capacity) {
+  capacity_ = RoundUp(capacity, Page::kPageSize);
+
+  // Over-estimate the size of chunks_ array.  It assumes the expansion of old
+  // space is always in the unit of a chunk (kChunkSize) except the last
+  // expansion.
+  //
+  // Due to alignment, allocated space might be one page less than required
+  // number (kPagesPerChunk) of pages for old spaces.
+  //
+  // Reserve two chunk ids for semispaces, one for map space, one for old
+  // space, and one for code space.
+  max_nof_chunks_ = (capacity_ / (kChunkSize - Page::kPageSize)) + 5;
+  if (max_nof_chunks_ > kMaxNofChunks) return false;
+
+  size_ = 0;
+  ChunkInfo info;  // uninitialized element.
+  for (int i = max_nof_chunks_ - 1; i >= 0; i--) {
+    chunks_.Add(info);
+    free_chunk_ids_.Add(i);
+  }
+  top_ = max_nof_chunks_;
+  return true;
+}
+
+
+void MemoryAllocator::TearDown() {
+  for (int i = 0; i < max_nof_chunks_; i++) {
+    if (chunks_[i].address() != NULL) DeleteChunk(i);
+  }
+  chunks_.Clear();
+  free_chunk_ids_.Clear();
+
+  if (initial_chunk_ != NULL) {
+    LOG(DeleteEvent("InitialChunk", initial_chunk_->address()));
+    delete initial_chunk_;
+    initial_chunk_ = NULL;
+  }
+
+  ASSERT(top_ == max_nof_chunks_);  // all chunks are free
+  top_ = 0;
+  capacity_ = 0;
+  size_ = 0;
+  max_nof_chunks_ = 0;
+}
+
+
+void* MemoryAllocator::AllocateRawMemory(const size_t requested,
+                                         size_t* allocated,
+                                         Executability executable) {
+  if (size_ + static_cast<int>(requested) > capacity_) return NULL;
+
+  void* mem = OS::Allocate(requested, allocated, executable == EXECUTABLE);
+  int alloced = *allocated;
+  size_ += alloced;
+  Counters::memory_allocated.Increment(alloced);
+  return mem;
+}
+
+
+void MemoryAllocator::FreeRawMemory(void* mem, size_t length) {
+  OS::Free(mem, length);
+  Counters::memory_allocated.Decrement(length);
+  size_ -= length;
+  ASSERT(size_ >= 0);
+}
+
+
+void* MemoryAllocator::ReserveInitialChunk(const size_t requested) {
+  ASSERT(initial_chunk_ == NULL);
+
+  initial_chunk_ = new VirtualMemory(requested);
+  CHECK(initial_chunk_ != NULL);
+  if (!initial_chunk_->IsReserved()) {
+    delete initial_chunk_;
+    initial_chunk_ = NULL;
+    return NULL;
+  }
+
+  // We are sure that we have mapped a block of requested addresses.
+  ASSERT(initial_chunk_->size() == requested);
+  LOG(NewEvent("InitialChunk", initial_chunk_->address(), requested));
+  size_ += requested;
+  return initial_chunk_->address();
+}
+
+
+static int PagesInChunk(Address start, size_t size) {
+  // The first page starts on the first page-aligned address from start onward
+  // and the last page ends on the last page-aligned address before
+  // start+size.  Page::kPageSize is a power of two so we can divide by
+  // shifting.
+  return (RoundDown(start + size, Page::kPageSize)
+          - RoundUp(start, Page::kPageSize)) >> Page::kPageSizeBits;
+}
+
+
+Page* MemoryAllocator::AllocatePages(int requested_pages, int* allocated_pages,
+                                     PagedSpace* owner) {
+  if (requested_pages <= 0) return Page::FromAddress(NULL);
+  size_t chunk_size = requested_pages * Page::kPageSize;
+
+  // There is not enough space to guarantee the desired number pages can be
+  // allocated.
+  if (size_ + static_cast<int>(chunk_size) > capacity_) {
+    // Request as many pages as we can.
+    chunk_size = capacity_ - size_;
+    requested_pages = chunk_size >> Page::kPageSizeBits;
+
+    if (requested_pages <= 0) return Page::FromAddress(NULL);
+  }
+  void* chunk = AllocateRawMemory(chunk_size, &chunk_size, owner->executable());
+  if (chunk == NULL) return Page::FromAddress(NULL);
+  LOG(NewEvent("PagedChunk", chunk, chunk_size));
+
+  *allocated_pages = PagesInChunk(static_cast<Address>(chunk), chunk_size);
+  if (*allocated_pages == 0) {
+    FreeRawMemory(chunk, chunk_size);
+    LOG(DeleteEvent("PagedChunk", chunk));
+    return Page::FromAddress(NULL);
+  }
+
+  int chunk_id = Pop();
+  chunks_[chunk_id].init(static_cast<Address>(chunk), chunk_size, owner);
+
+  return InitializePagesInChunk(chunk_id, *allocated_pages, owner);
+}
+
+
+Page* MemoryAllocator::CommitPages(Address start, size_t size,
+                                   PagedSpace* owner, int* num_pages) {
+  ASSERT(start != NULL);
+  *num_pages = PagesInChunk(start, size);
+  ASSERT(*num_pages > 0);
+  ASSERT(initial_chunk_ != NULL);
+  ASSERT(InInitialChunk(start));
+  ASSERT(InInitialChunk(start + size - 1));
+  if (!initial_chunk_->Commit(start, size, owner->executable() == EXECUTABLE)) {
+    return Page::FromAddress(NULL);
+  }
+  Counters::memory_allocated.Increment(size);
+
+  // So long as we correctly overestimated the number of chunks we should not
+  // run out of chunk ids.
+  CHECK(!OutOfChunkIds());
+  int chunk_id = Pop();
+  chunks_[chunk_id].init(start, size, owner);
+  return InitializePagesInChunk(chunk_id, *num_pages, owner);
+}
+
+
+bool MemoryAllocator::CommitBlock(Address start,
+                                  size_t size,
+                                  Executability executable) {
+  ASSERT(start != NULL);
+  ASSERT(size > 0);
+  ASSERT(initial_chunk_ != NULL);
+  ASSERT(InInitialChunk(start));
+  ASSERT(InInitialChunk(start + size - 1));
+
+  if (!initial_chunk_->Commit(start, size, executable)) return false;
+  Counters::memory_allocated.Increment(size);
+  return true;
+}
+
+
+Page* MemoryAllocator::InitializePagesInChunk(int chunk_id, int pages_in_chunk,
+                                              PagedSpace* owner) {
+  ASSERT(IsValidChunk(chunk_id));
+  ASSERT(pages_in_chunk > 0);
+
+  Address chunk_start = chunks_[chunk_id].address();
+
+  Address low = RoundUp(chunk_start, Page::kPageSize);
+
+#ifdef DEBUG
+  size_t chunk_size = chunks_[chunk_id].size();
+  Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize);
+  ASSERT(pages_in_chunk <=
+        ((OffsetFrom(high) - OffsetFrom(low)) / Page::kPageSize));
+#endif
+
+  Address page_addr = low;
+  for (int i = 0; i < pages_in_chunk; i++) {
+    Page* p = Page::FromAddress(page_addr);
+    p->opaque_header = OffsetFrom(page_addr + Page::kPageSize) | chunk_id;
+    p->is_normal_page = 1;
+    page_addr += Page::kPageSize;
+  }
+
+  // Set the next page of the last page to 0.
+  Page* last_page = Page::FromAddress(page_addr - Page::kPageSize);
+  last_page->opaque_header = OffsetFrom(0) | chunk_id;
+
+  return Page::FromAddress(low);
+}
+
+
+Page* MemoryAllocator::FreePages(Page* p) {
+  if (!p->is_valid()) return p;
+
+  // Find the first page in the same chunk as 'p'
+  Page* first_page = FindFirstPageInSameChunk(p);
+  Page* page_to_return = Page::FromAddress(NULL);
+
+  if (p != first_page) {
+    // Find the last page in the same chunk as 'prev'.
+    Page* last_page = FindLastPageInSameChunk(p);
+    first_page = GetNextPage(last_page);  // first page in next chunk
+
+    // set the next_page of last_page to NULL
+    SetNextPage(last_page, Page::FromAddress(NULL));
+    page_to_return = p;  // return 'p' when exiting
+  }
+
+  while (first_page->is_valid()) {
+    int chunk_id = GetChunkId(first_page);
+    ASSERT(IsValidChunk(chunk_id));
+
+    // Find the first page of the next chunk before deleting this chunk.
+    first_page = GetNextPage(FindLastPageInSameChunk(first_page));
+
+    // Free the current chunk.
+    DeleteChunk(chunk_id);
+  }
+
+  return page_to_return;
+}
+
+
+void MemoryAllocator::DeleteChunk(int chunk_id) {
+  ASSERT(IsValidChunk(chunk_id));
+
+  ChunkInfo& c = chunks_[chunk_id];
+
+  // We cannot free a chunk contained in the initial chunk because it was not
+  // allocated with AllocateRawMemory.  Instead we uncommit the virtual
+  // memory.
+  if (InInitialChunk(c.address())) {
+    // TODO(1240712): VirtualMemory::Uncommit has a return value which
+    // is ignored here.
+    initial_chunk_->Uncommit(c.address(), c.size());
+    Counters::memory_allocated.Decrement(c.size());
+  } else {
+    LOG(DeleteEvent("PagedChunk", c.address()));
+    FreeRawMemory(c.address(), c.size());
+  }
+  c.init(NULL, 0, NULL);
+  Push(chunk_id);
+}
+
+
+Page* MemoryAllocator::FindFirstPageInSameChunk(Page* p) {
+  int chunk_id = GetChunkId(p);
+  ASSERT(IsValidChunk(chunk_id));
+
+  Address low = RoundUp(chunks_[chunk_id].address(), Page::kPageSize);
+  return Page::FromAddress(low);
+}
+
+
+Page* MemoryAllocator::FindLastPageInSameChunk(Page* p) {
+  int chunk_id = GetChunkId(p);
+  ASSERT(IsValidChunk(chunk_id));
+
+  Address chunk_start = chunks_[chunk_id].address();
+  size_t chunk_size = chunks_[chunk_id].size();
+
+  Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize);
+  ASSERT(chunk_start <= p->address() && p->address() < high);
+
+  return Page::FromAddress(high - Page::kPageSize);
+}
+
+
+#ifdef DEBUG
+void MemoryAllocator::ReportStatistics() {
+  float pct = static_cast<float>(capacity_ - size_) / capacity_;
+  PrintF("  capacity: %d, used: %d, available: %%%d\n\n",
+         capacity_, size_, static_cast<int>(pct*100));
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// PagedSpace implementation
+
+PagedSpace::PagedSpace(int max_capacity,
+                       AllocationSpace id,
+                       Executability executable)
+    : Space(id, executable) {
+  max_capacity_ = (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize)
+                  * Page::kObjectAreaSize;
+  accounting_stats_.Clear();
+
+  allocation_info_.top = NULL;
+  allocation_info_.limit = NULL;
+
+  mc_forwarding_info_.top = NULL;
+  mc_forwarding_info_.limit = NULL;
+}
+
+
+bool PagedSpace::Setup(Address start, size_t size) {
+  if (HasBeenSetup()) return false;
+
+  int num_pages = 0;
+  // Try to use the virtual memory range passed to us.  If it is too small to
+  // contain at least one page, ignore it and allocate instead.
+  int pages_in_chunk = PagesInChunk(start, size);
+  if (pages_in_chunk > 0) {
+    first_page_ = MemoryAllocator::CommitPages(RoundUp(start, Page::kPageSize),
+                                               Page::kPageSize * pages_in_chunk,
+                                               this, &num_pages);
+  } else {
+    int requested_pages = Min(MemoryAllocator::kPagesPerChunk,
+                              max_capacity_ / Page::kObjectAreaSize);
+    first_page_ =
+        MemoryAllocator::AllocatePages(requested_pages, &num_pages, this);
+    if (!first_page_->is_valid()) return false;
+  }
+
+  // We are sure that the first page is valid and that we have at least one
+  // page.
+  ASSERT(first_page_->is_valid());
+  ASSERT(num_pages > 0);
+  accounting_stats_.ExpandSpace(num_pages * Page::kObjectAreaSize);
+  ASSERT(Capacity() <= max_capacity_);
+
+  for (Page* p = first_page_; p->is_valid(); p = p->next_page()) {
+    p->ClearRSet();
+  }
+
+  // Use first_page_ for allocation.
+  SetAllocationInfo(&allocation_info_, first_page_);
+
+  return true;
+}
+
+
+bool PagedSpace::HasBeenSetup() {
+  return (Capacity() > 0);
+}
+
+
+void PagedSpace::TearDown() {
+  first_page_ = MemoryAllocator::FreePages(first_page_);
+  ASSERT(!first_page_->is_valid());
+
+  accounting_stats_.Clear();
+}
+
+
+#ifdef ENABLE_HEAP_PROTECTION
+
+void PagedSpace::Protect() {
+  Page* page = first_page_;
+  while (page->is_valid()) {
+    MemoryAllocator::ProtectChunkFromPage(page);
+    page = MemoryAllocator::FindLastPageInSameChunk(page)->next_page();
+  }
+}
+
+
+void PagedSpace::Unprotect() {
+  Page* page = first_page_;
+  while (page->is_valid()) {
+    MemoryAllocator::UnprotectChunkFromPage(page);
+    page = MemoryAllocator::FindLastPageInSameChunk(page)->next_page();
+  }
+}
+
+#endif
+
+
+void PagedSpace::ClearRSet() {
+  PageIterator it(this, PageIterator::ALL_PAGES);
+  while (it.has_next()) {
+    it.next()->ClearRSet();
+  }
+}
+
+
+Object* PagedSpace::FindObject(Address addr) {
+  // Note: this function can only be called before or after mark-compact GC
+  // because it accesses map pointers.
+  ASSERT(!MarkCompactCollector::in_use());
+
+  if (!Contains(addr)) return Failure::Exception();
+
+  Page* p = Page::FromAddress(addr);
+  ASSERT(IsUsed(p));
+  Address cur = p->ObjectAreaStart();
+  Address end = p->AllocationTop();
+  while (cur < end) {
+    HeapObject* obj = HeapObject::FromAddress(cur);
+    Address next = cur + obj->Size();
+    if ((cur <= addr) && (addr < next)) return obj;
+    cur = next;
+  }
+
+  UNREACHABLE();
+  return Failure::Exception();
+}
+
+
+bool PagedSpace::IsUsed(Page* page) {
+  PageIterator it(this, PageIterator::PAGES_IN_USE);
+  while (it.has_next()) {
+    if (page == it.next()) return true;
+  }
+  return false;
+}
+
+
+void PagedSpace::SetAllocationInfo(AllocationInfo* alloc_info, Page* p) {
+  alloc_info->top = p->ObjectAreaStart();
+  alloc_info->limit = p->ObjectAreaEnd();
+  ASSERT(alloc_info->VerifyPagedAllocation());
+}
+
+
+void PagedSpace::MCResetRelocationInfo() {
+  // Set page indexes.
+  int i = 0;
+  PageIterator it(this, PageIterator::ALL_PAGES);
+  while (it.has_next()) {
+    Page* p = it.next();
+    p->mc_page_index = i++;
+  }
+
+  // Set mc_forwarding_info_ to the first page in the space.
+  SetAllocationInfo(&mc_forwarding_info_, first_page_);
+  // All the bytes in the space are 'available'.  We will rediscover
+  // allocated and wasted bytes during GC.
+  accounting_stats_.Reset();
+}
+
+
+int PagedSpace::MCSpaceOffsetForAddress(Address addr) {
+#ifdef DEBUG
+  // The Contains function considers the address at the beginning of a
+  // page in the page, MCSpaceOffsetForAddress considers it is in the
+  // previous page.
+  if (Page::IsAlignedToPageSize(addr)) {
+    ASSERT(Contains(addr - kPointerSize));
+  } else {
+    ASSERT(Contains(addr));
+  }
+#endif
+
+  // If addr is at the end of a page, it belongs to previous page
+  Page* p = Page::IsAlignedToPageSize(addr)
+            ? Page::FromAllocationTop(addr)
+            : Page::FromAddress(addr);
+  int index = p->mc_page_index;
+  return (index * Page::kPageSize) + p->Offset(addr);
+}
+
+
+// Slow case for reallocating and promoting objects during a compacting
+// collection.  This function is not space-specific.
+HeapObject* PagedSpace::SlowMCAllocateRaw(int size_in_bytes) {
+  Page* current_page = TopPageOf(mc_forwarding_info_);
+  if (!current_page->next_page()->is_valid()) {
+    if (!Expand(current_page)) {
+      return NULL;
+    }
+  }
+
+  // There are surely more pages in the space now.
+  ASSERT(current_page->next_page()->is_valid());
+  // We do not add the top of page block for current page to the space's
+  // free list---the block may contain live objects so we cannot write
+  // bookkeeping information to it.  Instead, we will recover top of page
+  // blocks when we move objects to their new locations.
+  //
+  // We do however write the allocation pointer to the page.  The encoding
+  // of forwarding addresses is as an offset in terms of live bytes, so we
+  // need quick access to the allocation top of each page to decode
+  // forwarding addresses.
+  current_page->mc_relocation_top = mc_forwarding_info_.top;
+  SetAllocationInfo(&mc_forwarding_info_, current_page->next_page());
+  return AllocateLinearly(&mc_forwarding_info_, size_in_bytes);
+}
+
+
+bool PagedSpace::Expand(Page* last_page) {
+  ASSERT(max_capacity_ % Page::kObjectAreaSize == 0);
+  ASSERT(Capacity() % Page::kObjectAreaSize == 0);
+
+  if (Capacity() == max_capacity_) return false;
+
+  ASSERT(Capacity() < max_capacity_);
+  // Last page must be valid and its next page is invalid.
+  ASSERT(last_page->is_valid() && !last_page->next_page()->is_valid());
+
+  int available_pages = (max_capacity_ - Capacity()) / Page::kObjectAreaSize;
+  if (available_pages <= 0) return false;
+
+  int desired_pages = Min(available_pages, MemoryAllocator::kPagesPerChunk);
+  Page* p = MemoryAllocator::AllocatePages(desired_pages, &desired_pages, this);
+  if (!p->is_valid()) return false;
+
+  accounting_stats_.ExpandSpace(desired_pages * Page::kObjectAreaSize);
+  ASSERT(Capacity() <= max_capacity_);
+
+  MemoryAllocator::SetNextPage(last_page, p);
+
+  // Clear remembered set of new pages.
+  while (p->is_valid()) {
+    p->ClearRSet();
+    p = p->next_page();
+  }
+
+  return true;
+}
+
+
+#ifdef DEBUG
+int PagedSpace::CountTotalPages() {
+  int count = 0;
+  for (Page* p = first_page_; p->is_valid(); p = p->next_page()) {
+    count++;
+  }
+  return count;
+}
+#endif
+
+
+void PagedSpace::Shrink() {
+  // Release half of free pages.
+  Page* top_page = AllocationTopPage();
+  ASSERT(top_page->is_valid());
+
+  // Loop over the pages from the top page to the end of the space to count
+  // the number of pages to keep and find the last page to keep.
+  int free_pages = 0;
+  int pages_to_keep = 0;  // Of the free pages.
+  Page* last_page_to_keep = top_page;
+  Page* current_page = top_page->next_page();
+  // Loop over the pages to the end of the space.
+  while (current_page->is_valid()) {
+    // Advance last_page_to_keep every other step to end up at the midpoint.
+    if ((free_pages & 0x1) == 1) {
+      pages_to_keep++;
+      last_page_to_keep = last_page_to_keep->next_page();
+    }
+    free_pages++;
+    current_page = current_page->next_page();
+  }
+
+  // Free pages after last_page_to_keep, and adjust the next_page link.
+  Page* p = MemoryAllocator::FreePages(last_page_to_keep->next_page());
+  MemoryAllocator::SetNextPage(last_page_to_keep, p);
+
+  // Since pages are only freed in whole chunks, we may have kept more than
+  // pages_to_keep.
+  while (p->is_valid()) {
+    pages_to_keep++;
+    p = p->next_page();
+  }
+
+  // The difference between free_pages and pages_to_keep is the number of
+  // pages actually freed.
+  ASSERT(pages_to_keep <= free_pages);
+  int bytes_freed = (free_pages - pages_to_keep) * Page::kObjectAreaSize;
+  accounting_stats_.ShrinkSpace(bytes_freed);
+
+  ASSERT(Capacity() == CountTotalPages() * Page::kObjectAreaSize);
+}
+
+
+bool PagedSpace::EnsureCapacity(int capacity) {
+  if (Capacity() >= capacity) return true;
+
+  // Start from the allocation top and loop to the last page in the space.
+  Page* last_page = AllocationTopPage();
+  Page* next_page = last_page->next_page();
+  while (next_page->is_valid()) {
+    last_page = MemoryAllocator::FindLastPageInSameChunk(next_page);
+    next_page = last_page->next_page();
+  }
+
+  // Expand the space until it has the required capacity or expansion fails.
+  do {
+    if (!Expand(last_page)) return false;
+    ASSERT(last_page->next_page()->is_valid());
+    last_page =
+        MemoryAllocator::FindLastPageInSameChunk(last_page->next_page());
+  } while (Capacity() < capacity);
+
+  return true;
+}
+
+
+#ifdef DEBUG
+void PagedSpace::Print() { }
+#endif
+
+
+// -----------------------------------------------------------------------------
+// NewSpace implementation
+
+
+bool NewSpace::Setup(Address start, int size) {
+  // Setup new space based on the preallocated memory block defined by
+  // start and size. The provided space is divided into two semi-spaces.
+  // To support fast containment testing in the new space, the size of
+  // this chunk must be a power of two and it must be aligned to its size.
+  int initial_semispace_capacity = Heap::InitialSemiSpaceSize();
+  int maximum_semispace_capacity = Heap::SemiSpaceSize();
+
+  ASSERT(initial_semispace_capacity <= maximum_semispace_capacity);
+  ASSERT(IsPowerOf2(maximum_semispace_capacity));
+  maximum_capacity_ = maximum_semispace_capacity;
+  capacity_ = initial_semispace_capacity;
+
+  // Allocate and setup the histogram arrays if necessary.
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+  allocated_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
+  promoted_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
+
+#define SET_NAME(name) allocated_histogram_[name].set_name(#name); \
+                       promoted_histogram_[name].set_name(#name);
+  INSTANCE_TYPE_LIST(SET_NAME)
+#undef SET_NAME
+#endif
+
+  ASSERT(size == 2 * maximum_capacity_);
+  ASSERT(IsAddressAligned(start, size, 0));
+
+  if (!to_space_.Setup(start, capacity_, maximum_capacity_)) {
+    return false;
+  }
+  if (!from_space_.Setup(start + maximum_capacity_,
+                         capacity_,
+                         maximum_capacity_)) {
+    return false;
+  }
+
+  start_ = start;
+  address_mask_ = ~(size - 1);
+  object_mask_ = address_mask_ | kHeapObjectTag;
+  object_expected_ = reinterpret_cast<uint32_t>(start) | kHeapObjectTag;
+
+  allocation_info_.top = to_space_.low();
+  allocation_info_.limit = to_space_.high();
+  mc_forwarding_info_.top = NULL;
+  mc_forwarding_info_.limit = NULL;
+
+  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+  return true;
+}
+
+
+void NewSpace::TearDown() {
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+  if (allocated_histogram_) {
+    DeleteArray(allocated_histogram_);
+    allocated_histogram_ = NULL;
+  }
+  if (promoted_histogram_) {
+    DeleteArray(promoted_histogram_);
+    promoted_histogram_ = NULL;
+  }
+#endif
+
+  start_ = NULL;
+  capacity_ = 0;
+  allocation_info_.top = NULL;
+  allocation_info_.limit = NULL;
+  mc_forwarding_info_.top = NULL;
+  mc_forwarding_info_.limit = NULL;
+
+  to_space_.TearDown();
+  from_space_.TearDown();
+}
+
+
+#ifdef ENABLE_HEAP_PROTECTION
+
+void NewSpace::Protect() {
+  MemoryAllocator::Protect(ToSpaceLow(), Capacity());
+  MemoryAllocator::Protect(FromSpaceLow(), Capacity());
+}
+
+
+void NewSpace::Unprotect() {
+  MemoryAllocator::Unprotect(ToSpaceLow(), Capacity(),
+                             to_space_.executable());
+  MemoryAllocator::Unprotect(FromSpaceLow(), Capacity(),
+                             from_space_.executable());
+}
+
+#endif
+
+
+void NewSpace::Flip() {
+  SemiSpace tmp = from_space_;
+  from_space_ = to_space_;
+  to_space_ = tmp;
+}
+
+
+bool NewSpace::Double() {
+  ASSERT(capacity_ <= maximum_capacity_ / 2);
+  // TODO(1240712): Failure to double the from space can result in
+  // semispaces of different sizes.  In the event of that failure, the
+  // to space doubling should be rolled back before returning false.
+  if (!to_space_.Double() || !from_space_.Double()) return false;
+  capacity_ *= 2;
+  allocation_info_.limit = to_space_.high();
+  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+  return true;
+}
+
+
+void NewSpace::ResetAllocationInfo() {
+  allocation_info_.top = to_space_.low();
+  allocation_info_.limit = to_space_.high();
+  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+void NewSpace::MCResetRelocationInfo() {
+  mc_forwarding_info_.top = from_space_.low();
+  mc_forwarding_info_.limit = from_space_.high();
+  ASSERT_SEMISPACE_ALLOCATION_INFO(mc_forwarding_info_, from_space_);
+}
+
+
+void NewSpace::MCCommitRelocationInfo() {
+  // Assumes that the spaces have been flipped so that mc_forwarding_info_ is
+  // valid allocation info for the to space.
+  allocation_info_.top = mc_forwarding_info_.top;
+  allocation_info_.limit = to_space_.high();
+  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+#ifdef DEBUG
+// We do not use the SemispaceIterator because verification doesn't assume
+// that it works (it depends on the invariants we are checking).
+void NewSpace::Verify() {
+  // The allocation pointer should be in the space or at the very end.
+  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+
+  // There should be objects packed in from the low address up to the
+  // allocation pointer.
+  Address current = to_space_.low();
+  while (current < top()) {
+    HeapObject* object = HeapObject::FromAddress(current);
+
+    // The first word should be a map, and we expect all map pointers to
+    // be in map space.
+    Map* map = object->map();
+    ASSERT(map->IsMap());
+    ASSERT(Heap::map_space()->Contains(map));
+
+    // The object should not be code or a map.
+    ASSERT(!object->IsMap());
+    ASSERT(!object->IsCode());
+
+    // The object itself should look OK.
+    object->Verify();
+
+    // All the interior pointers should be contained in the heap.
+    VerifyPointersVisitor visitor;
+    int size = object->Size();
+    object->IterateBody(map->instance_type(), size, &visitor);
+
+    current += size;
+  }
+
+  // The allocation pointer should not be in the middle of an object.
+  ASSERT(current == top());
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// SemiSpace implementation
+
+bool SemiSpace::Setup(Address start,
+                      int initial_capacity,
+                      int maximum_capacity) {
+  // Creates a space in the young generation. The constructor does not
+  // allocate memory from the OS.  A SemiSpace is given a contiguous chunk of
+  // memory of size 'capacity' when set up, and does not grow or shrink
+  // otherwise.  In the mark-compact collector, the memory region of the from
+  // space is used as the marking stack. It requires contiguous memory
+  // addresses.
+  capacity_ = initial_capacity;
+  maximum_capacity_ = maximum_capacity;
+
+  if (!MemoryAllocator::CommitBlock(start, capacity_, executable())) {
+    return false;
+  }
+
+  start_ = start;
+  address_mask_ = ~(maximum_capacity - 1);
+  object_mask_ = address_mask_ | kHeapObjectTag;
+  object_expected_ = reinterpret_cast<uint32_t>(start) | kHeapObjectTag;
+
+  age_mark_ = start_;
+  return true;
+}
+
+
+void SemiSpace::TearDown() {
+  start_ = NULL;
+  capacity_ = 0;
+}
+
+
+bool SemiSpace::Double() {
+  if (!MemoryAllocator::CommitBlock(high(), capacity_, executable())) {
+    return false;
+  }
+  capacity_ *= 2;
+  return true;
+}
+
+
+#ifdef DEBUG
+void SemiSpace::Print() { }
+
+
+void SemiSpace::Verify() { }
+#endif
+
+
+// -----------------------------------------------------------------------------
+// SemiSpaceIterator implementation.
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) {
+  Initialize(space, space->bottom(), space->top(), NULL);
+}
+
+
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space,
+                                     HeapObjectCallback size_func) {
+  Initialize(space, space->bottom(), space->top(), size_func);
+}
+
+
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, Address start) {
+  Initialize(space, start, space->top(), NULL);
+}
+
+
+void SemiSpaceIterator::Initialize(NewSpace* space, Address start,
+                                   Address end,
+                                   HeapObjectCallback size_func) {
+  ASSERT(space->ToSpaceContains(start));
+  ASSERT(space->ToSpaceLow() <= end
+         && end <= space->ToSpaceHigh());
+  space_ = &space->to_space_;
+  current_ = start;
+  limit_ = end;
+  size_func_ = size_func;
+}
+
+
+#ifdef DEBUG
+// A static array of histogram info for each type.
+static HistogramInfo heap_histograms[LAST_TYPE+1];
+static JSObject::SpillInformation js_spill_information;
+
+// heap_histograms is shared, always clear it before using it.
+static void ClearHistograms() {
+  // We reset the name each time, though it hasn't changed.
+#define DEF_TYPE_NAME(name) heap_histograms[name].set_name(#name);
+  INSTANCE_TYPE_LIST(DEF_TYPE_NAME)
+#undef DEF_TYPE_NAME
+
+#define CLEAR_HISTOGRAM(name) heap_histograms[name].clear();
+  INSTANCE_TYPE_LIST(CLEAR_HISTOGRAM)
+#undef CLEAR_HISTOGRAM
+
+  js_spill_information.Clear();
+}
+
+
+static int code_kind_statistics[Code::NUMBER_OF_KINDS];
+
+
+static void ClearCodeKindStatistics() {
+  for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) {
+    code_kind_statistics[i] = 0;
+  }
+}
+
+
+static void ReportCodeKindStatistics() {
+  const char* table[Code::NUMBER_OF_KINDS];
+
+#define CASE(name)                            \
+  case Code::name: table[Code::name] = #name; \
+  break
+
+  for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) {
+    switch (static_cast<Code::Kind>(i)) {
+      CASE(FUNCTION);
+      CASE(STUB);
+      CASE(BUILTIN);
+      CASE(LOAD_IC);
+      CASE(KEYED_LOAD_IC);
+      CASE(STORE_IC);
+      CASE(KEYED_STORE_IC);
+      CASE(CALL_IC);
+    }
+  }
+
+#undef CASE
+
+  PrintF("\n   Code kind histograms: \n");
+  for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) {
+    if (code_kind_statistics[i] > 0) {
+      PrintF("     %-20s: %10d bytes\n", table[i], code_kind_statistics[i]);
+    }
+  }
+  PrintF("\n");
+}
+
+
+static int CollectHistogramInfo(HeapObject* obj) {
+  InstanceType type = obj->map()->instance_type();
+  ASSERT(0 <= type && type <= LAST_TYPE);
+  ASSERT(heap_histograms[type].name() != NULL);
+  heap_histograms[type].increment_number(1);
+  heap_histograms[type].increment_bytes(obj->Size());
+
+  if (FLAG_collect_heap_spill_statistics && obj->IsJSObject()) {
+    JSObject::cast(obj)->IncrementSpillStatistics(&js_spill_information);
+  }
+
+  return obj->Size();
+}
+
+
+static void ReportHistogram(bool print_spill) {
+  PrintF("\n  Object Histogram:\n");
+  for (int i = 0; i <= LAST_TYPE; i++) {
+    if (heap_histograms[i].number() > 0) {
+      PrintF("    %-33s%10d (%10d bytes)\n",
+             heap_histograms[i].name(),
+             heap_histograms[i].number(),
+             heap_histograms[i].bytes());
+    }
+  }
+  PrintF("\n");
+
+  // Summarize string types.
+  int string_number = 0;
+  int string_bytes = 0;
+#define INCREMENT(type, size, name)                  \
+    string_number += heap_histograms[type].number(); \
+    string_bytes += heap_histograms[type].bytes();
+  STRING_TYPE_LIST(INCREMENT)
+#undef INCREMENT
+  if (string_number > 0) {
+    PrintF("    %-33s%10d (%10d bytes)\n\n", "STRING_TYPE", string_number,
+           string_bytes);
+  }
+
+  if (FLAG_collect_heap_spill_statistics && print_spill) {
+    js_spill_information.Print();
+  }
+}
+#endif  // DEBUG
+
+
+// Support for statistics gathering for --heap-stats and --log-gc.
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+void NewSpace::ClearHistograms() {
+  for (int i = 0; i <= LAST_TYPE; i++) {
+    allocated_histogram_[i].clear();
+    promoted_histogram_[i].clear();
+  }
+}
+
+// Because the copying collector does not touch garbage objects, we iterate
+// the new space before a collection to get a histogram of allocated objects.
+// This only happens (1) when compiled with DEBUG and the --heap-stats flag is
+// set, or when compiled with ENABLE_LOGGING_AND_PROFILING and the --log-gc
+// flag is set.
+void NewSpace::CollectStatistics() {
+  ClearHistograms();
+  SemiSpaceIterator it(this);
+  while (it.has_next()) RecordAllocation(it.next());
+}
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+static void DoReportStatistics(HistogramInfo* info, const char* description) {
+  LOG(HeapSampleBeginEvent("NewSpace", description));
+  // Lump all the string types together.
+  int string_number = 0;
+  int string_bytes = 0;
+#define INCREMENT(type, size, name)       \
+    string_number += info[type].number(); \
+    string_bytes += info[type].bytes();
+  STRING_TYPE_LIST(INCREMENT)
+#undef INCREMENT
+  if (string_number > 0) {
+    LOG(HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes));
+  }
+
+  // Then do the other types.
+  for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) {
+    if (info[i].number() > 0) {
+      LOG(HeapSampleItemEvent(info[i].name(), info[i].number(),
+                              info[i].bytes()));
+    }
+  }
+  LOG(HeapSampleEndEvent("NewSpace", description));
+}
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+
+void NewSpace::ReportStatistics() {
+#ifdef DEBUG
+  if (FLAG_heap_stats) {
+    float pct = static_cast<float>(Available()) / Capacity();
+    PrintF("  capacity: %d, available: %d, %%%d\n",
+           Capacity(), Available(), static_cast<int>(pct*100));
+    PrintF("\n  Object Histogram:\n");
+    for (int i = 0; i <= LAST_TYPE; i++) {
+      if (allocated_histogram_[i].number() > 0) {
+        PrintF("    %-33s%10d (%10d bytes)\n",
+               allocated_histogram_[i].name(),
+               allocated_histogram_[i].number(),
+               allocated_histogram_[i].bytes());
+      }
+    }
+    PrintF("\n");
+  }
+#endif  // DEBUG
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (FLAG_log_gc) {
+    DoReportStatistics(allocated_histogram_, "allocated");
+    DoReportStatistics(promoted_histogram_, "promoted");
+  }
+#endif  // ENABLE_LOGGING_AND_PROFILING
+}
+
+
+void NewSpace::RecordAllocation(HeapObject* obj) {
+  InstanceType type = obj->map()->instance_type();
+  ASSERT(0 <= type && type <= LAST_TYPE);
+  allocated_histogram_[type].increment_number(1);
+  allocated_histogram_[type].increment_bytes(obj->Size());
+}
+
+
+void NewSpace::RecordPromotion(HeapObject* obj) {
+  InstanceType type = obj->map()->instance_type();
+  ASSERT(0 <= type && type <= LAST_TYPE);
+  promoted_histogram_[type].increment_number(1);
+  promoted_histogram_[type].increment_bytes(obj->Size());
+}
+#endif  // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+
+
+// -----------------------------------------------------------------------------
+// Free lists for old object spaces implementation
+
+void FreeListNode::set_size(int size_in_bytes) {
+  ASSERT(size_in_bytes > 0);
+  ASSERT(IsAligned(size_in_bytes, kPointerSize));
+
+  // We write a map and possibly size information to the block.  If the block
+  // is big enough to be a ByteArray with at least one extra word (the next
+  // pointer), we set its map to be the byte array map and its size to an
+  // appropriate array length for the desired size from HeapObject::Size().
+  // If the block is too small (eg, one or two words), to hold both a size
+  // field and a next pointer, we give it a filler map that gives it the
+  // correct size.
+  if (size_in_bytes > Array::kHeaderSize) {
+    set_map(Heap::byte_array_map());
+    ByteArray::cast(this)->set_length(ByteArray::LengthFor(size_in_bytes));
+  } else if (size_in_bytes == kPointerSize) {
+    set_map(Heap::one_word_filler_map());
+  } else if (size_in_bytes == 2 * kPointerSize) {
+    set_map(Heap::two_word_filler_map());
+  } else {
+    UNREACHABLE();
+  }
+  ASSERT(Size() == size_in_bytes);
+}
+
+
+Address FreeListNode::next() {
+  ASSERT(map() == Heap::byte_array_map());
+  ASSERT(Size() >= kNextOffset + kPointerSize);
+  return Memory::Address_at(address() + kNextOffset);
+}
+
+
+void FreeListNode::set_next(Address next) {
+  ASSERT(map() == Heap::byte_array_map());
+  ASSERT(Size() >= kNextOffset + kPointerSize);
+  Memory::Address_at(address() + kNextOffset) = next;
+}
+
+
+OldSpaceFreeList::OldSpaceFreeList(AllocationSpace owner) : owner_(owner) {
+  Reset();
+}
+
+
+void OldSpaceFreeList::Reset() {
+  available_ = 0;
+  for (int i = 0; i < kFreeListsLength; i++) {
+    free_[i].head_node_ = NULL;
+  }
+  needs_rebuild_ = false;
+  finger_ = kHead;
+  free_[kHead].next_size_ = kEnd;
+}
+
+
+void OldSpaceFreeList::RebuildSizeList() {
+  ASSERT(needs_rebuild_);
+  int cur = kHead;
+  for (int i = cur + 1; i < kFreeListsLength; i++) {
+    if (free_[i].head_node_ != NULL) {
+      free_[cur].next_size_ = i;
+      cur = i;
+    }
+  }
+  free_[cur].next_size_ = kEnd;
+  needs_rebuild_ = false;
+}
+
+
+int OldSpaceFreeList::Free(Address start, int size_in_bytes) {
+#ifdef DEBUG
+  for (int i = 0; i < size_in_bytes; i += kPointerSize) {
+    Memory::Address_at(start + i) = kZapValue;
+  }
+#endif
+  FreeListNode* node = FreeListNode::FromAddress(start);
+  node->set_size(size_in_bytes);
+
+  // Early return to drop too-small blocks on the floor (one or two word
+  // blocks cannot hold a map pointer, a size field, and a pointer to the
+  // next block in the free list).
+  if (size_in_bytes < kMinBlockSize) {
+    return size_in_bytes;
+  }
+
+  // Insert other blocks at the head of an exact free list.
+  int index = size_in_bytes >> kPointerSizeLog2;
+  node->set_next(free_[index].head_node_);
+  free_[index].head_node_ = node->address();
+  available_ += size_in_bytes;
+  needs_rebuild_ = true;
+  return 0;
+}
+
+
+Object* OldSpaceFreeList::Allocate(int size_in_bytes, int* wasted_bytes) {
+  ASSERT(0 < size_in_bytes);
+  ASSERT(size_in_bytes <= kMaxBlockSize);
+  ASSERT(IsAligned(size_in_bytes, kPointerSize));
+
+  if (needs_rebuild_) RebuildSizeList();
+  int index = size_in_bytes >> kPointerSizeLog2;
+  // Check for a perfect fit.
+  if (free_[index].head_node_ != NULL) {
+    FreeListNode* node = FreeListNode::FromAddress(free_[index].head_node_);
+    // If this was the last block of its size, remove the size.
+    if ((free_[index].head_node_ = node->next()) == NULL) RemoveSize(index);
+    available_ -= size_in_bytes;
+    *wasted_bytes = 0;
+    return node;
+  }
+  // Search the size list for the best fit.
+  int prev = finger_ < index ? finger_ : kHead;
+  int cur = FindSize(index, &prev);
+  ASSERT(index < cur);
+  if (cur == kEnd) {
+    // No large enough size in list.
+    *wasted_bytes = 0;
+    return Failure::RetryAfterGC(size_in_bytes, owner_);
+  }
+  int rem = cur - index;
+  int rem_bytes = rem << kPointerSizeLog2;
+  FreeListNode* cur_node = FreeListNode::FromAddress(free_[cur].head_node_);
+  ASSERT(cur_node->Size() == (cur << kPointerSizeLog2));
+  FreeListNode* rem_node = FreeListNode::FromAddress(free_[cur].head_node_ +
+                                                     size_in_bytes);
+  // Distinguish the cases prev < rem < cur and rem <= prev < cur
+  // to avoid many redundant tests and calls to Insert/RemoveSize.
+  if (prev < rem) {
+    // Simple case: insert rem between prev and cur.
+    finger_ = prev;
+    free_[prev].next_size_ = rem;
+    // If this was the last block of size cur, remove the size.
+    if ((free_[cur].head_node_ = cur_node->next()) == NULL) {
+      free_[rem].next_size_ = free_[cur].next_size_;
+    } else {
+      free_[rem].next_size_ = cur;
+    }
+    // Add the remainder block.
+    rem_node->set_size(rem_bytes);
+    rem_node->set_next(free_[rem].head_node_);
+    free_[rem].head_node_ = rem_node->address();
+  } else {
+    // If this was the last block of size cur, remove the size.
+    if ((free_[cur].head_node_ = cur_node->next()) == NULL) {
+      finger_ = prev;
+      free_[prev].next_size_ = free_[cur].next_size_;
+    }
+    if (rem_bytes < kMinBlockSize) {
+      // Too-small remainder is wasted.
+      rem_node->set_size(rem_bytes);
+      available_ -= size_in_bytes + rem_bytes;
+      *wasted_bytes = rem_bytes;
+      return cur_node;
+    }
+    // Add the remainder block and, if needed, insert its size.
+    rem_node->set_size(rem_bytes);
+    rem_node->set_next(free_[rem].head_node_);
+    free_[rem].head_node_ = rem_node->address();
+    if (rem_node->next() == NULL) InsertSize(rem);
+  }
+  available_ -= size_in_bytes;
+  *wasted_bytes = 0;
+  return cur_node;
+}
+
+
+#ifdef DEBUG
+bool OldSpaceFreeList::Contains(FreeListNode* node) {
+  for (int i = 0; i < kFreeListsLength; i++) {
+    Address cur_addr = free_[i].head_node_;
+    while (cur_addr != NULL) {
+      FreeListNode* cur_node = FreeListNode::FromAddress(cur_addr);
+      if (cur_node == node) return true;
+      cur_addr = cur_node->next();
+    }
+  }
+  return false;
+}
+#endif
+
+
+MapSpaceFreeList::MapSpaceFreeList(AllocationSpace owner) {
+  owner_ = owner;
+  Reset();
+}
+
+
+void MapSpaceFreeList::Reset() {
+  available_ = 0;
+  head_ = NULL;
+}
+
+
+void MapSpaceFreeList::Free(Address start) {
+#ifdef DEBUG
+  for (int i = 0; i < Map::kSize; i += kPointerSize) {
+    Memory::Address_at(start + i) = kZapValue;
+  }
+#endif
+  FreeListNode* node = FreeListNode::FromAddress(start);
+  node->set_size(Map::kSize);
+  node->set_next(head_);
+  head_ = node->address();
+  available_ += Map::kSize;
+}
+
+
+Object* MapSpaceFreeList::Allocate() {
+  if (head_ == NULL) {
+    return Failure::RetryAfterGC(Map::kSize, owner_);
+  }
+
+  FreeListNode* node = FreeListNode::FromAddress(head_);
+  head_ = node->next();
+  available_ -= Map::kSize;
+  return node;
+}
+
+
+// -----------------------------------------------------------------------------
+// OldSpace implementation
+
+void OldSpace::PrepareForMarkCompact(bool will_compact) {
+  if (will_compact) {
+    // Reset relocation info.  During a compacting collection, everything in
+    // the space is considered 'available' and we will rediscover live data
+    // and waste during the collection.
+    MCResetRelocationInfo();
+    mc_end_of_relocation_ = bottom();
+    ASSERT(Available() == Capacity());
+  } else {
+    // During a non-compacting collection, everything below the linear
+    // allocation pointer is considered allocated (everything above is
+    // available) and we will rediscover available and wasted bytes during
+    // the collection.
+    accounting_stats_.AllocateBytes(free_list_.available());
+    accounting_stats_.FillWastedBytes(Waste());
+  }
+
+  // Clear the free list before a full GC---it will be rebuilt afterward.
+  free_list_.Reset();
+}
+
+
+void OldSpace::MCAdjustRelocationEnd(Address address, int size_in_bytes) {
+  ASSERT(Contains(address));
+  Address current_top = mc_end_of_relocation_;
+  Page* current_page = Page::FromAllocationTop(current_top);
+
+  // No more objects relocated to this page?  Move to the next.
+  ASSERT(current_top <= current_page->mc_relocation_top);
+  if (current_top == current_page->mc_relocation_top) {
+    // The space should already be properly expanded.
+    Page* next_page = current_page->next_page();
+    CHECK(next_page->is_valid());
+    mc_end_of_relocation_ = next_page->ObjectAreaStart();
+  }
+  ASSERT(mc_end_of_relocation_ == address);
+  mc_end_of_relocation_ += size_in_bytes;
+}
+
+
+void OldSpace::MCCommitRelocationInfo() {
+  // Update fast allocation info.
+  allocation_info_.top = mc_forwarding_info_.top;
+  allocation_info_.limit = mc_forwarding_info_.limit;
+  ASSERT(allocation_info_.VerifyPagedAllocation());
+
+  // The space is compacted and we haven't yet built free lists or
+  // wasted any space.
+  ASSERT(Waste() == 0);
+  ASSERT(AvailableFree() == 0);
+
+  // Build the free list for the space.
+  int computed_size = 0;
+  PageIterator it(this, PageIterator::PAGES_USED_BY_MC);
+  while (it.has_next()) {
+    Page* p = it.next();
+    // Space below the relocation pointer is allocated.
+    computed_size += p->mc_relocation_top - p->ObjectAreaStart();
+    if (it.has_next()) {
+      // Free the space at the top of the page.  We cannot use
+      // p->mc_relocation_top after the call to Free (because Free will clear
+      // remembered set bits).
+      int extra_size = p->ObjectAreaEnd() - p->mc_relocation_top;
+      if (extra_size > 0) {
+        int wasted_bytes = free_list_.Free(p->mc_relocation_top, extra_size);
+        // The bytes we have just "freed" to add to the free list were
+        // already accounted as available.
+        accounting_stats_.WasteBytes(wasted_bytes);
+      }
+    }
+  }
+
+  // Make sure the computed size - based on the used portion of the pages in
+  // use - matches the size obtained while computing forwarding addresses.
+  ASSERT(computed_size == Size());
+}
+
+
+// Slow case for normal allocation.  Try in order: (1) allocate in the next
+// page in the space, (2) allocate off the space's free list, (3) expand the
+// space, (4) fail.
+HeapObject* OldSpace::SlowAllocateRaw(int size_in_bytes) {
+  // Linear allocation in this space has failed.  If there is another page
+  // in the space, move to that page and allocate there.  This allocation
+  // should succeed (size_in_bytes should not be greater than a page's
+  // object area size).
+  Page* current_page = TopPageOf(allocation_info_);
+  if (current_page->next_page()->is_valid()) {
+    return AllocateInNextPage(current_page, size_in_bytes);
+  }
+
+  // There is no next page in this space.  Try free list allocation.
+  int wasted_bytes;
+  Object* result = free_list_.Allocate(size_in_bytes, &wasted_bytes);
+  accounting_stats_.WasteBytes(wasted_bytes);
+  if (!result->IsFailure()) {
+    accounting_stats_.AllocateBytes(size_in_bytes);
+    return HeapObject::cast(result);
+  }
+
+  // Free list allocation failed and there is no next page.  Fail if we have
+  // hit the old generation size limit that should cause a garbage
+  // collection.
+  if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) {
+    return NULL;
+  }
+
+  // Try to expand the space and allocate in the new next page.
+  ASSERT(!current_page->next_page()->is_valid());
+  if (Expand(current_page)) {
+    return AllocateInNextPage(current_page, size_in_bytes);
+  }
+
+  // Finally, fail.
+  return NULL;
+}
+
+
+// Add the block at the top of the page to the space's free list, set the
+// allocation info to the next page (assumed to be one), and allocate
+// linearly there.
+HeapObject* OldSpace::AllocateInNextPage(Page* current_page,
+                                         int size_in_bytes) {
+  ASSERT(current_page->next_page()->is_valid());
+  // Add the block at the top of this page to the free list.
+  int free_size = current_page->ObjectAreaEnd() - allocation_info_.top;
+  if (free_size > 0) {
+    int wasted_bytes = free_list_.Free(allocation_info_.top, free_size);
+    accounting_stats_.WasteBytes(wasted_bytes);
+  }
+  SetAllocationInfo(&allocation_info_, current_page->next_page());
+  return AllocateLinearly(&allocation_info_, size_in_bytes);
+}
+
+
+#ifdef DEBUG
+// We do not assume that the PageIterator works, because it depends on the
+// invariants we are checking during verification.
+void OldSpace::Verify() {
+  // The allocation pointer should be valid, and it should be in a page in the
+  // space.
+  ASSERT(allocation_info_.VerifyPagedAllocation());
+  Page* top_page = Page::FromAllocationTop(allocation_info_.top);
+  ASSERT(MemoryAllocator::IsPageInSpace(top_page, this));
+
+  // Loop over all the pages.
+  bool above_allocation_top = false;
+  Page* current_page = first_page_;
+  while (current_page->is_valid()) {
+    if (above_allocation_top) {
+      // We don't care what's above the allocation top.
+    } else {
+      // Unless this is the last page in the space containing allocated
+      // objects, the allocation top should be at the object area end.
+      Address top = current_page->AllocationTop();
+      if (current_page == top_page) {
+        ASSERT(top == allocation_info_.top);
+        // The next page will be above the allocation top.
+        above_allocation_top = true;
+      } else {
+        ASSERT(top == current_page->ObjectAreaEnd());
+      }
+
+      // It should be packed with objects from the bottom to the top.
+      Address current = current_page->ObjectAreaStart();
+      while (current < top) {
+        HeapObject* object = HeapObject::FromAddress(current);
+
+        // The first word should be a map, and we expect all map pointers to
+        // be in map space.
+        Map* map = object->map();
+        ASSERT(map->IsMap());
+        ASSERT(Heap::map_space()->Contains(map));
+
+        // The object should not be a map.
+        ASSERT(!object->IsMap());
+
+        // The object itself should look OK.
+        object->Verify();
+
+        // All the interior pointers should be contained in the heap and have
+        // their remembered set bits set if they point to new space.  Code
+        // objects do not have remembered set bits that we care about.
+        VerifyPointersAndRSetVisitor rset_visitor;
+        VerifyPointersVisitor no_rset_visitor;
+        int size = object->Size();
+        if (object->IsCode()) {
+          Code::cast(object)->ConvertICTargetsFromAddressToObject();
+          object->IterateBody(map->instance_type(), size, &no_rset_visitor);
+          Code::cast(object)->ConvertICTargetsFromObjectToAddress();
+        } else {
+          object->IterateBody(map->instance_type(), size, &rset_visitor);
+        }
+
+        current += size;
+      }
+
+      // The allocation pointer should not be in the middle of an object.
+      ASSERT(current == top);
+    }
+
+    current_page = current_page->next_page();
+  }
+}
+
+
+struct CommentStatistic {
+  const char* comment;
+  int size;
+  int count;
+  void Clear() {
+    comment = NULL;
+    size = 0;
+    count = 0;
+  }
+};
+
+
+// must be small, since an iteration is used for lookup
+const int kMaxComments = 64;
+static CommentStatistic comments_statistics[kMaxComments+1];
+
+
+void PagedSpace::ReportCodeStatistics() {
+  ReportCodeKindStatistics();
+  PrintF("Code comment statistics (\"   [ comment-txt   :    size/   "
+         "count  (average)\"):\n");
+  for (int i = 0; i <= kMaxComments; i++) {
+    const CommentStatistic& cs = comments_statistics[i];
+    if (cs.size > 0) {
+      PrintF("   %-30s: %10d/%6d     (%d)\n", cs.comment, cs.size, cs.count,
+             cs.size/cs.count);
+    }
+  }
+  PrintF("\n");
+}
+
+
+void PagedSpace::ResetCodeStatistics() {
+  ClearCodeKindStatistics();
+  for (int i = 0; i < kMaxComments; i++) comments_statistics[i].Clear();
+  comments_statistics[kMaxComments].comment = "Unknown";
+  comments_statistics[kMaxComments].size = 0;
+  comments_statistics[kMaxComments].count = 0;
+}
+
+
+// Adds comment to 'comment_statistics' table. Performance OK sa long as
+// 'kMaxComments' is small
+static void EnterComment(const char* comment, int delta) {
+  // Do not count empty comments
+  if (delta <= 0) return;
+  CommentStatistic* cs = &comments_statistics[kMaxComments];
+  // Search for a free or matching entry in 'comments_statistics': 'cs'
+  // points to result.
+  for (int i = 0; i < kMaxComments; i++) {
+    if (comments_statistics[i].comment == NULL) {
+      cs = &comments_statistics[i];
+      cs->comment = comment;
+      break;
+    } else if (strcmp(comments_statistics[i].comment, comment) == 0) {
+      cs = &comments_statistics[i];
+      break;
+    }
+  }
+  // Update entry for 'comment'
+  cs->size += delta;
+  cs->count += 1;
+}
+
+
+// Call for each nested comment start (start marked with '[ xxx', end marked
+// with ']'.  RelocIterator 'it' must point to a comment reloc info.
+static void CollectCommentStatistics(RelocIterator* it) {
+  ASSERT(!it->done());
+  ASSERT(it->rinfo()->rmode() == RelocInfo::COMMENT);
+  const char* tmp = reinterpret_cast<const char*>(it->rinfo()->data());
+  if (tmp[0] != '[') {
+    // Not a nested comment; skip
+    return;
+  }
+
+  // Search for end of nested comment or a new nested comment
+  const char* const comment_txt =
+      reinterpret_cast<const char*>(it->rinfo()->data());
+  const byte* prev_pc = it->rinfo()->pc();
+  int flat_delta = 0;
+  it->next();
+  while (true) {
+    // All nested comments must be terminated properly, and therefore exit
+    // from loop.
+    ASSERT(!it->done());
+    if (it->rinfo()->rmode() == RelocInfo::COMMENT) {
+      const char* const txt =
+          reinterpret_cast<const char*>(it->rinfo()->data());
+      flat_delta += it->rinfo()->pc() - prev_pc;
+      if (txt[0] == ']') break;  // End of nested  comment
+      // A new comment
+      CollectCommentStatistics(it);
+      // Skip code that was covered with previous comment
+      prev_pc = it->rinfo()->pc();
+    }
+    it->next();
+  }
+  EnterComment(comment_txt, flat_delta);
+}
+
+
+// Collects code size statistics:
+// - by code kind
+// - by code comment
+void PagedSpace::CollectCodeStatistics() {
+  HeapObjectIterator obj_it(this);
+  while (obj_it.has_next()) {
+    HeapObject* obj = obj_it.next();
+    if (obj->IsCode()) {
+      Code* code = Code::cast(obj);
+      code_kind_statistics[code->kind()] += code->Size();
+      RelocIterator it(code);
+      int delta = 0;
+      const byte* prev_pc = code->instruction_start();
+      while (!it.done()) {
+        if (it.rinfo()->rmode() == RelocInfo::COMMENT) {
+          delta += it.rinfo()->pc() - prev_pc;
+          CollectCommentStatistics(&it);
+          prev_pc = it.rinfo()->pc();
+        }
+        it.next();
+      }
+
+      ASSERT(code->instruction_start() <= prev_pc &&
+             prev_pc <= code->relocation_start());
+      delta += code->relocation_start() - prev_pc;
+      EnterComment("NoComment", delta);
+    }
+  }
+}
+
+
+void OldSpace::ReportStatistics() {
+  int pct = Available() * 100 / Capacity();
+  PrintF("  capacity: %d, waste: %d, available: %d, %%%d\n",
+         Capacity(), Waste(), Available(), pct);
+
+  // Report remembered set statistics.
+  int rset_marked_pointers = 0;
+  int rset_marked_arrays = 0;
+  int rset_marked_array_elements = 0;
+  int cross_gen_pointers = 0;
+  int cross_gen_array_elements = 0;
+
+  PageIterator page_it(this, PageIterator::PAGES_IN_USE);
+  while (page_it.has_next()) {
+    Page* p = page_it.next();
+
+    for (Address rset_addr = p->RSetStart();
+         rset_addr < p->RSetEnd();
+         rset_addr += kIntSize) {
+      int rset = Memory::int_at(rset_addr);
+      if (rset != 0) {
+        // Bits were set
+        int intoff = rset_addr - p->address();
+        int bitoff = 0;
+        for (; bitoff < kBitsPerInt; ++bitoff) {
+          if ((rset & (1 << bitoff)) != 0) {
+            int bitpos = intoff*kBitsPerByte + bitoff;
+            Address slot = p->OffsetToAddress(bitpos << kObjectAlignmentBits);
+            Object** obj = reinterpret_cast<Object**>(slot);
+            if (*obj == Heap::fixed_array_map()) {
+              rset_marked_arrays++;
+              FixedArray* fa = FixedArray::cast(HeapObject::FromAddress(slot));
+
+              rset_marked_array_elements += fa->length();
+              // Manually inline FixedArray::IterateBody
+              Address elm_start = slot + FixedArray::kHeaderSize;
+              Address elm_stop = elm_start + fa->length() * kPointerSize;
+              for (Address elm_addr = elm_start;
+                   elm_addr < elm_stop; elm_addr += kPointerSize) {
+                // Filter non-heap-object pointers
+                Object** elm_p = reinterpret_cast<Object**>(elm_addr);
+                if (Heap::InNewSpace(*elm_p))
+                  cross_gen_array_elements++;
+              }
+            } else {
+              rset_marked_pointers++;
+              if (Heap::InNewSpace(*obj))
+                cross_gen_pointers++;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  pct = rset_marked_pointers == 0 ?
+        0 : cross_gen_pointers * 100 / rset_marked_pointers;
+  PrintF("  rset-marked pointers %d, to-new-space %d (%%%d)\n",
+            rset_marked_pointers, cross_gen_pointers, pct);
+  PrintF("  rset_marked arrays %d, ", rset_marked_arrays);
+  PrintF("  elements %d, ", rset_marked_array_elements);
+  pct = rset_marked_array_elements == 0 ? 0
+           : cross_gen_array_elements * 100 / rset_marked_array_elements;
+  PrintF("  pointers to new space %d (%%%d)\n", cross_gen_array_elements, pct);
+  PrintF("  total rset-marked bits %d\n",
+            (rset_marked_pointers + rset_marked_arrays));
+  pct = (rset_marked_pointers + rset_marked_array_elements) == 0 ? 0
+        : (cross_gen_pointers + cross_gen_array_elements) * 100 /
+          (rset_marked_pointers + rset_marked_array_elements);
+  PrintF("  total rset pointers %d, true cross generation ones %d (%%%d)\n",
+         (rset_marked_pointers + rset_marked_array_elements),
+         (cross_gen_pointers + cross_gen_array_elements),
+         pct);
+
+  ClearHistograms();
+  HeapObjectIterator obj_it(this);
+  while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); }
+  ReportHistogram(true);
+}
+
+
+// Dump the range of remembered set words between [start, end) corresponding
+// to the pointers starting at object_p.  The allocation_top is an object
+// pointer which should not be read past.  This is important for large object
+// pages, where some bits in the remembered set range do not correspond to
+// allocated addresses.
+static void PrintRSetRange(Address start, Address end, Object** object_p,
+                           Address allocation_top) {
+  Address rset_address = start;
+
+  // If the range starts on on odd numbered word (eg, for large object extra
+  // remembered set ranges), print some spaces.
+  if ((reinterpret_cast<uint32_t>(start) / kIntSize) % 2 == 1) {
+    PrintF("                                    ");
+  }
+
+  // Loop over all the words in the range.
+  while (rset_address < end) {
+    uint32_t rset_word = Memory::uint32_at(rset_address);
+    int bit_position = 0;
+
+    // Loop over all the bits in the word.
+    while (bit_position < kBitsPerInt) {
+      if (object_p == reinterpret_cast<Object**>(allocation_top)) {
+        // Print a bar at the allocation pointer.
+        PrintF("|");
+      } else if (object_p > reinterpret_cast<Object**>(allocation_top)) {
+        // Do not dereference object_p past the allocation pointer.
+        PrintF("#");
+      } else if ((rset_word & (1 << bit_position)) == 0) {
+        // Print a dot for zero bits.
+        PrintF(".");
+      } else if (Heap::InNewSpace(*object_p)) {
+        // Print an X for one bits for pointers to new space.
+        PrintF("X");
+      } else {
+        // Print a circle for one bits for pointers to old space.
+        PrintF("o");
+      }
+
+      // Print a space after every 8th bit except the last.
+      if (bit_position % 8 == 7 && bit_position != (kBitsPerInt - 1)) {
+        PrintF(" ");
+      }
+
+      // Advance to next bit.
+      bit_position++;
+      object_p++;
+    }
+
+    // Print a newline after every odd numbered word, otherwise a space.
+    if ((reinterpret_cast<uint32_t>(rset_address) / kIntSize) % 2 == 1) {
+      PrintF("\n");
+    } else {
+      PrintF(" ");
+    }
+
+    // Advance to next remembered set word.
+    rset_address += kIntSize;
+  }
+}
+
+
+void PagedSpace::DoPrintRSet(const char* space_name) {
+  PageIterator it(this, PageIterator::PAGES_IN_USE);
+  while (it.has_next()) {
+    Page* p = it.next();
+    PrintF("%s page 0x%x:\n", space_name, p);
+    PrintRSetRange(p->RSetStart(), p->RSetEnd(),
+                   reinterpret_cast<Object**>(p->ObjectAreaStart()),
+                   p->AllocationTop());
+    PrintF("\n");
+  }
+}
+
+
+void OldSpace::PrintRSet() { DoPrintRSet("old"); }
+#endif
+
+// -----------------------------------------------------------------------------
+// MapSpace implementation
+
+void MapSpace::PrepareForMarkCompact(bool will_compact) {
+  if (will_compact) {
+    // Reset relocation info.
+    MCResetRelocationInfo();
+
+    // Initialize map index entry.
+    int page_count = 0;
+    PageIterator it(this, PageIterator::ALL_PAGES);
+    while (it.has_next()) {
+      ASSERT_MAP_PAGE_INDEX(page_count);
+
+      Page* p = it.next();
+      ASSERT(p->mc_page_index == page_count);
+
+      page_addresses_[page_count++] = p->address();
+    }
+
+    // During a compacting collection, everything in the space is considered
+    // 'available' (set by the call to MCResetRelocationInfo) and we will
+    // rediscover live and wasted bytes during the collection.
+    ASSERT(Available() == Capacity());
+  } else {
+    // During a non-compacting collection, everything below the linear
+    // allocation pointer except wasted top-of-page blocks is considered
+    // allocated and we will rediscover available bytes during the
+    // collection.
+    accounting_stats_.AllocateBytes(free_list_.available());
+  }
+
+  // Clear the free list before a full GC---it will be rebuilt afterward.
+  free_list_.Reset();
+}
+
+
+void MapSpace::MCCommitRelocationInfo() {
+  // Update fast allocation info.
+  allocation_info_.top = mc_forwarding_info_.top;
+  allocation_info_.limit = mc_forwarding_info_.limit;
+  ASSERT(allocation_info_.VerifyPagedAllocation());
+
+  // The space is compacted and we haven't yet wasted any space.
+  ASSERT(Waste() == 0);
+
+  // Update allocation_top of each page in use and compute waste.
+  int computed_size = 0;
+  PageIterator it(this, PageIterator::PAGES_USED_BY_MC);
+  while (it.has_next()) {
+    Page* page = it.next();
+    Address page_top = page->AllocationTop();
+    computed_size += page_top - page->ObjectAreaStart();
+    if (it.has_next()) {
+      accounting_stats_.WasteBytes(page->ObjectAreaEnd() - page_top);
+    }
+  }
+
+  // Make sure the computed size - based on the used portion of the
+  // pages in use - matches the size we adjust during allocation.
+  ASSERT(computed_size == Size());
+}
+
+
+// Slow case for normal allocation. Try in order: (1) allocate in the next
+// page in the space, (2) allocate off the space's free list, (3) expand the
+// space, (4) fail.
+HeapObject* MapSpace::SlowAllocateRaw(int size_in_bytes) {
+  // Linear allocation in this space has failed.  If there is another page
+  // in the space, move to that page and allocate there.  This allocation
+  // should succeed.
+  Page* current_page = TopPageOf(allocation_info_);
+  if (current_page->next_page()->is_valid()) {
+    return AllocateInNextPage(current_page, size_in_bytes);
+  }
+
+  // There is no next page in this space.  Try free list allocation.  The
+  // map space free list implicitly assumes that all free blocks are map
+  // sized.
+  if (size_in_bytes == Map::kSize) {
+    Object* result = free_list_.Allocate();
+    if (!result->IsFailure()) {
+      accounting_stats_.AllocateBytes(size_in_bytes);
+      return HeapObject::cast(result);
+    }
+  }
+
+  // Free list allocation failed and there is no next page.  Fail if we have
+  // hit the old generation size limit that should cause a garbage
+  // collection.
+  if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) {
+    return NULL;
+  }
+
+  // Try to expand the space and allocate in the new next page.
+  ASSERT(!current_page->next_page()->is_valid());
+  if (Expand(current_page)) {
+    return AllocateInNextPage(current_page, size_in_bytes);
+  }
+
+  // Finally, fail.
+  return NULL;
+}
+
+
+// Move to the next page (there is assumed to be one) and allocate there.
+// The top of page block is always wasted, because it is too small to hold a
+// map.
+HeapObject* MapSpace::AllocateInNextPage(Page* current_page,
+                                         int size_in_bytes) {
+  ASSERT(current_page->next_page()->is_valid());
+  ASSERT(current_page->ObjectAreaEnd() - allocation_info_.top == kPageExtra);
+  accounting_stats_.WasteBytes(kPageExtra);
+  SetAllocationInfo(&allocation_info_, current_page->next_page());
+  return AllocateLinearly(&allocation_info_, size_in_bytes);
+}
+
+
+#ifdef DEBUG
+// We do not assume that the PageIterator works, because it depends on the
+// invariants we are checking during verification.
+void MapSpace::Verify() {
+  // The allocation pointer should be valid, and it should be in a page in the
+  // space.
+  ASSERT(allocation_info_.VerifyPagedAllocation());
+  Page* top_page = Page::FromAllocationTop(allocation_info_.top);
+  ASSERT(MemoryAllocator::IsPageInSpace(top_page, this));
+
+  // Loop over all the pages.
+  bool above_allocation_top = false;
+  Page* current_page = first_page_;
+  while (current_page->is_valid()) {
+    if (above_allocation_top) {
+      // We don't care what's above the allocation top.
+    } else {
+      // Unless this is the last page in the space containing allocated
+      // objects, the allocation top should be at a constant offset from the
+      // object area end.
+      Address top = current_page->AllocationTop();
+      if (current_page == top_page) {
+        ASSERT(top == allocation_info_.top);
+        // The next page will be above the allocation top.
+        above_allocation_top = true;
+      } else {
+        ASSERT(top == current_page->ObjectAreaEnd() - kPageExtra);
+      }
+
+      // It should be packed with objects from the bottom to the top.
+      Address current = current_page->ObjectAreaStart();
+      while (current < top) {
+        HeapObject* object = HeapObject::FromAddress(current);
+
+        // The first word should be a map, and we expect all map pointers to
+        // be in map space.
+        Map* map = object->map();
+        ASSERT(map->IsMap());
+        ASSERT(Heap::map_space()->Contains(map));
+
+        // The object should be a map or a byte array.
+        ASSERT(object->IsMap() || object->IsByteArray());
+
+        // The object itself should look OK.
+        object->Verify();
+
+        // All the interior pointers should be contained in the heap and
+        // have their remembered set bits set if they point to new space.
+        VerifyPointersAndRSetVisitor visitor;
+        int size = object->Size();
+        object->IterateBody(map->instance_type(), size, &visitor);
+
+        current += size;
+      }
+
+      // The allocation pointer should not be in the middle of an object.
+      ASSERT(current == top);
+    }
+
+    current_page = current_page->next_page();
+  }
+}
+
+
+void MapSpace::ReportStatistics() {
+  int pct = Available() * 100 / Capacity();
+  PrintF("  capacity: %d, waste: %d, available: %d, %%%d\n",
+         Capacity(), Waste(), Available(), pct);
+
+  // Report remembered set statistics.
+  int rset_marked_pointers = 0;
+  int cross_gen_pointers = 0;
+
+  PageIterator page_it(this, PageIterator::PAGES_IN_USE);
+  while (page_it.has_next()) {
+    Page* p = page_it.next();
+
+    for (Address rset_addr = p->RSetStart();
+         rset_addr < p->RSetEnd();
+         rset_addr += kIntSize) {
+      int rset = Memory::int_at(rset_addr);
+      if (rset != 0) {
+        // Bits were set
+        int intoff = rset_addr - p->address();
+        int bitoff = 0;
+        for (; bitoff < kBitsPerInt; ++bitoff) {
+          if ((rset & (1 << bitoff)) != 0) {
+            int bitpos = intoff*kBitsPerByte + bitoff;
+            Address slot = p->OffsetToAddress(bitpos << kObjectAlignmentBits);
+            Object** obj = reinterpret_cast<Object**>(slot);
+            rset_marked_pointers++;
+            if (Heap::InNewSpace(*obj))
+              cross_gen_pointers++;
+          }
+        }
+      }
+    }
+  }
+
+  pct = rset_marked_pointers == 0 ?
+          0 : cross_gen_pointers * 100 / rset_marked_pointers;
+  PrintF("  rset-marked pointers %d, to-new-space %d (%%%d)\n",
+            rset_marked_pointers, cross_gen_pointers, pct);
+
+  ClearHistograms();
+  HeapObjectIterator obj_it(this);
+  while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); }
+  ReportHistogram(false);
+}
+
+
+void MapSpace::PrintRSet() { DoPrintRSet("map"); }
+#endif
+
+
+// -----------------------------------------------------------------------------
+// LargeObjectIterator
+
+LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) {
+  current_ = space->first_chunk_;
+  size_func_ = NULL;
+}
+
+
+LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space,
+                                         HeapObjectCallback size_func) {
+  current_ = space->first_chunk_;
+  size_func_ = size_func;
+}
+
+
+HeapObject* LargeObjectIterator::next() {
+  ASSERT(has_next());
+  HeapObject* object = current_->GetObject();
+  current_ = current_->next();
+  return object;
+}
+
+
+// -----------------------------------------------------------------------------
+// LargeObjectChunk
+
+LargeObjectChunk* LargeObjectChunk::New(int size_in_bytes,
+                                        size_t* chunk_size,
+                                        Executability executable) {
+  size_t requested = ChunkSizeFor(size_in_bytes);
+  void* mem = MemoryAllocator::AllocateRawMemory(requested,
+                                                 chunk_size,
+                                                 executable);
+  if (mem == NULL) return NULL;
+  LOG(NewEvent("LargeObjectChunk", mem, *chunk_size));
+  if (*chunk_size < requested) {
+    MemoryAllocator::FreeRawMemory(mem, *chunk_size);
+    LOG(DeleteEvent("LargeObjectChunk", mem));
+    return NULL;
+  }
+  return reinterpret_cast<LargeObjectChunk*>(mem);
+}
+
+
+int LargeObjectChunk::ChunkSizeFor(int size_in_bytes) {
+  int os_alignment = OS::AllocateAlignment();
+  if (os_alignment < Page::kPageSize)
+    size_in_bytes += (Page::kPageSize - os_alignment);
+  return size_in_bytes + Page::kObjectStartOffset;
+}
+
+// -----------------------------------------------------------------------------
+// LargeObjectSpace
+
+LargeObjectSpace::LargeObjectSpace(AllocationSpace id)
+    : Space(id, NOT_EXECUTABLE),  // Managed on a per-allocation basis
+      first_chunk_(NULL),
+      size_(0),
+      page_count_(0) {}
+
+
+bool LargeObjectSpace::Setup() {
+  first_chunk_ = NULL;
+  size_ = 0;
+  page_count_ = 0;
+  return true;
+}
+
+
+void LargeObjectSpace::TearDown() {
+  while (first_chunk_ != NULL) {
+    LargeObjectChunk* chunk = first_chunk_;
+    first_chunk_ = first_chunk_->next();
+    LOG(DeleteEvent("LargeObjectChunk", chunk->address()));
+    MemoryAllocator::FreeRawMemory(chunk->address(), chunk->size());
+  }
+
+  size_ = 0;
+  page_count_ = 0;
+}
+
+
+#ifdef ENABLE_HEAP_PROTECTION
+
+void LargeObjectSpace::Protect() {
+  LargeObjectChunk* chunk = first_chunk_;
+  while (chunk != NULL) {
+    MemoryAllocator::Protect(chunk->address(), chunk->size());
+    chunk = chunk->next();
+  }
+}
+
+
+void LargeObjectSpace::Unprotect() {
+  LargeObjectChunk* chunk = first_chunk_;
+  while (chunk != NULL) {
+    bool is_code = chunk->GetObject()->IsCode();
+    MemoryAllocator::Unprotect(chunk->address(), chunk->size(),
+                               is_code ? EXECUTABLE : NOT_EXECUTABLE);
+    chunk = chunk->next();
+  }
+}
+
+#endif
+
+
+Object* LargeObjectSpace::AllocateRawInternal(int requested_size,
+                                              int object_size,
+                                              Executability executable) {
+  ASSERT(0 < object_size && object_size <= requested_size);
+
+  // Check if we want to force a GC before growing the old space further.
+  // If so, fail the allocation.
+  if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) {
+    return Failure::RetryAfterGC(requested_size, identity());
+  }
+
+  size_t chunk_size;
+  LargeObjectChunk* chunk =
+      LargeObjectChunk::New(requested_size, &chunk_size, executable);
+  if (chunk == NULL) {
+    return Failure::RetryAfterGC(requested_size, identity());
+  }
+
+  size_ += chunk_size;
+  page_count_++;
+  chunk->set_next(first_chunk_);
+  chunk->set_size(chunk_size);
+  first_chunk_ = chunk;
+
+  // Set the object address and size in the page header and clear its
+  // remembered set.
+  Page* page = Page::FromAddress(RoundUp(chunk->address(), Page::kPageSize));
+  Address object_address = page->ObjectAreaStart();
+  // Clear the low order bit of the second word in the page to flag it as a
+  // large object page.  If the chunk_size happened to be written there, its
+  // low order bit should already be clear.
+  ASSERT((chunk_size & 0x1) == 0);
+  page->is_normal_page &= ~0x1;
+  page->ClearRSet();
+  int extra_bytes = requested_size - object_size;
+  if (extra_bytes > 0) {
+    // The extra memory for the remembered set should be cleared.
+    memset(object_address + object_size, 0, extra_bytes);
+  }
+
+  return HeapObject::FromAddress(object_address);
+}
+
+
+Object* LargeObjectSpace::AllocateRawCode(int size_in_bytes) {
+  ASSERT(0 < size_in_bytes);
+  return AllocateRawInternal(size_in_bytes,
+                             size_in_bytes,
+                             EXECUTABLE);
+}
+
+
+Object* LargeObjectSpace::AllocateRawFixedArray(int size_in_bytes) {
+  ASSERT(0 < size_in_bytes);
+  int extra_rset_bytes = ExtraRSetBytesFor(size_in_bytes);
+  return AllocateRawInternal(size_in_bytes + extra_rset_bytes,
+                             size_in_bytes,
+                             NOT_EXECUTABLE);
+}
+
+
+Object* LargeObjectSpace::AllocateRaw(int size_in_bytes) {
+  ASSERT(0 < size_in_bytes);
+  return AllocateRawInternal(size_in_bytes,
+                             size_in_bytes,
+                             NOT_EXECUTABLE);
+}
+
+
+// GC support
+Object* LargeObjectSpace::FindObject(Address a) {
+  for (LargeObjectChunk* chunk = first_chunk_;
+       chunk != NULL;
+       chunk = chunk->next()) {
+    Address chunk_address = chunk->address();
+    if (chunk_address <= a && a < chunk_address + chunk->size()) {
+      return chunk->GetObject();
+    }
+  }
+  return Failure::Exception();
+}
+
+
+void LargeObjectSpace::ClearRSet() {
+  ASSERT(Page::is_rset_in_use());
+
+  LargeObjectIterator it(this);
+  while (it.has_next()) {
+    HeapObject* object = it.next();
+    // We only have code, sequential strings, or fixed arrays in large
+    // object space, and only fixed arrays need remembered set support.
+    if (object->IsFixedArray()) {
+      // Clear the normal remembered set region of the page;
+      Page* page = Page::FromAddress(object->address());
+      page->ClearRSet();
+
+      // Clear the extra remembered set.
+      int size = object->Size();
+      int extra_rset_bytes = ExtraRSetBytesFor(size);
+      memset(object->address() + size, 0, extra_rset_bytes);
+    }
+  }
+}
+
+
+void LargeObjectSpace::IterateRSet(ObjectSlotCallback copy_object_func) {
+  ASSERT(Page::is_rset_in_use());
+
+  LargeObjectIterator it(this);
+  while (it.has_next()) {
+    // We only have code, sequential strings, or fixed arrays in large
+    // object space, and only fixed arrays can possibly contain pointers to
+    // the young generation.
+    HeapObject* object = it.next();
+    if (object->IsFixedArray()) {
+      // Iterate the normal page remembered set range.
+      Page* page = Page::FromAddress(object->address());
+      Address object_end = object->address() + object->Size();
+      Heap::IterateRSetRange(page->ObjectAreaStart(),
+                             Min(page->ObjectAreaEnd(), object_end),
+                             page->RSetStart(),
+                             copy_object_func);
+
+      // Iterate the extra array elements.
+      if (object_end > page->ObjectAreaEnd()) {
+        Heap::IterateRSetRange(page->ObjectAreaEnd(), object_end,
+                               object_end, copy_object_func);
+      }
+    }
+  }
+}
+
+
+void LargeObjectSpace::FreeUnmarkedObjects() {
+  LargeObjectChunk* previous = NULL;
+  LargeObjectChunk* current = first_chunk_;
+  while (current != NULL) {
+    HeapObject* object = current->GetObject();
+    if (object->IsMarked()) {
+      object->ClearMark();
+      MarkCompactCollector::tracer()->decrement_marked_count();
+      previous = current;
+      current = current->next();
+    } else {
+      Address chunk_address = current->address();
+      size_t chunk_size = current->size();
+
+      // Cut the chunk out from the chunk list.
+      current = current->next();
+      if (previous == NULL) {
+        first_chunk_ = current;
+      } else {
+        previous->set_next(current);
+      }
+
+      // Free the chunk.
+      if (object->IsCode()) {
+        LOG(CodeDeleteEvent(object->address()));
+      }
+      size_ -= chunk_size;
+      page_count_--;
+      MemoryAllocator::FreeRawMemory(chunk_address, chunk_size);
+      LOG(DeleteEvent("LargeObjectChunk", chunk_address));
+    }
+  }
+}
+
+
+bool LargeObjectSpace::Contains(HeapObject* object) {
+  Address address = object->address();
+  Page* page = Page::FromAddress(address);
+
+  SLOW_ASSERT(!page->IsLargeObjectPage()
+              || !FindObject(address)->IsFailure());
+
+  return page->IsLargeObjectPage();
+}
+
+
+#ifdef DEBUG
+// We do not assume that the large object iterator works, because it depends
+// on the invariants we are checking during verification.
+void LargeObjectSpace::Verify() {
+  for (LargeObjectChunk* chunk = first_chunk_;
+       chunk != NULL;
+       chunk = chunk->next()) {
+    // Each chunk contains an object that starts at the large object page's
+    // object area start.
+    HeapObject* object = chunk->GetObject();
+    Page* page = Page::FromAddress(object->address());
+    ASSERT(object->address() == page->ObjectAreaStart());
+
+    // The first word should be a map, and we expect all map pointers to be
+    // in map space.
+    Map* map = object->map();
+    ASSERT(map->IsMap());
+    ASSERT(Heap::map_space()->Contains(map));
+
+    // We have only code, sequential strings, fixed arrays, and byte arrays
+    // in large object space.
+    ASSERT(object->IsCode() || object->IsSeqString()
+           || object->IsFixedArray() || object->IsByteArray());
+
+    // The object itself should look OK.
+    object->Verify();
+
+    // Byte arrays and strings don't have interior pointers.
+    if (object->IsCode()) {
+      VerifyPointersVisitor code_visitor;
+      Code::cast(object)->ConvertICTargetsFromAddressToObject();
+      object->IterateBody(map->instance_type(),
+                          object->Size(),
+                          &code_visitor);
+      Code::cast(object)->ConvertICTargetsFromObjectToAddress();
+    } else if (object->IsFixedArray()) {
+      // We loop over fixed arrays ourselves, rather then using the visitor,
+      // because the visitor doesn't support the start/offset iteration
+      // needed for IsRSetSet.
+      FixedArray* array = FixedArray::cast(object);
+      for (int j = 0; j < array->length(); j++) {
+        Object* element = array->get(j);
+        if (element->IsHeapObject()) {
+          HeapObject* element_object = HeapObject::cast(element);
+          ASSERT(Heap::Contains(element_object));
+          ASSERT(element_object->map()->IsMap());
+          if (Heap::InNewSpace(element_object)) {
+            ASSERT(Page::IsRSetSet(object->address(),
+                                   FixedArray::kHeaderSize + j * kPointerSize));
+          }
+        }
+      }
+    }
+  }
+}
+
+
+void LargeObjectSpace::Print() {
+  LargeObjectIterator it(this);
+  while (it.has_next()) {
+    it.next()->Print();
+  }
+}
+
+
+void LargeObjectSpace::ReportStatistics() {
+  PrintF("  size: %d\n", size_);
+  int num_objects = 0;
+  ClearHistograms();
+  LargeObjectIterator it(this);
+  while (it.has_next()) {
+    num_objects++;
+    CollectHistogramInfo(it.next());
+  }
+
+  PrintF("  number of objects %d\n", num_objects);
+  if (num_objects > 0) ReportHistogram(false);
+}
+
+
+void LargeObjectSpace::CollectCodeStatistics() {
+  LargeObjectIterator obj_it(this);
+  while (obj_it.has_next()) {
+    HeapObject* obj = obj_it.next();
+    if (obj->IsCode()) {
+      Code* code = Code::cast(obj);
+      code_kind_statistics[code->kind()] += code->Size();
+    }
+  }
+}
+
+
+void LargeObjectSpace::PrintRSet() {
+  LargeObjectIterator it(this);
+  while (it.has_next()) {
+    HeapObject* object = it.next();
+    if (object->IsFixedArray()) {
+      Page* page = Page::FromAddress(object->address());
+
+      Address allocation_top = object->address() + object->Size();
+      PrintF("large page 0x%x:\n", page);
+      PrintRSetRange(page->RSetStart(), page->RSetEnd(),
+                     reinterpret_cast<Object**>(object->address()),
+                     allocation_top);
+      int extra_array_bytes = object->Size() - Page::kObjectAreaSize;
+      int extra_rset_bits = RoundUp(extra_array_bytes / kPointerSize,
+                                    kBitsPerInt);
+      PrintF("------------------------------------------------------------"
+             "-----------\n");
+      PrintRSetRange(allocation_top,
+                     allocation_top + extra_rset_bits / kBitsPerByte,
+                     reinterpret_cast<Object**>(object->address()
+                                                + Page::kObjectAreaSize),
+                     allocation_top);
+      PrintF("\n");
+    }
+  }
+}
+#endif  // DEBUG
+
+} }  // namespace v8::internal