CSE2410 Fall 2014 Bounce

// Copyright 2011 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.

#ifndef V8_SPACES_INL_H_

#define V8_SPACES_INL_H_

#include "heap-profiler.h"

#include "isolate.h"

#include "spaces.h"

#include "v8memory.h"

namespace v8 {

namespace internal {

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

// Bitmap

void Bitmap::Clear(MemoryChunk* chunk) {

  Bitmap* bitmap = chunk->markbits();

  for (int i = 0; i < bitmap->CellsCount(); i++) bitmap->cells()[i] = 0;

  chunk->ResetLiveBytes();

}

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

// PageIterator

PageIterator::PageIterator(PagedSpace* space)

    : space_(space),

      prev_page_(&space->anchor_),

      next_page_(prev_page_->next_page()) { }

bool PageIterator::has_next() {

  return next_page_ != &space_->anchor_;

}

Page* PageIterator::next() {

  ASSERT(has_next());

  prev_page_ = next_page_;

  next_page_ = next_page_->next_page();

  return prev_page_;

}

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

// NewSpacePageIterator

NewSpacePageIterator::NewSpacePageIterator(NewSpace* space)

    : prev_page_(NewSpacePage::FromAddress(space->ToSpaceStart())->prev_page()),

      next_page_(NewSpacePage::FromAddress(space->ToSpaceStart())),

      last_page_(NewSpacePage::FromLimit(space->ToSpaceEnd())) { }

NewSpacePageIterator::NewSpacePageIterator(SemiSpace* space)

    : prev_page_(space->anchor()),

      next_page_(prev_page_->next_page()),

      last_page_(prev_page_->prev_page()) { }

NewSpacePageIterator::NewSpacePageIterator(Address start, Address limit)

    : prev_page_(NewSpacePage::FromAddress(start)->prev_page()),

      next_page_(NewSpacePage::FromAddress(start)),

      last_page_(NewSpacePage::FromLimit(limit)) {

  SemiSpace::AssertValidRange(start, limit);

}

bool NewSpacePageIterator::has_next() {

  return prev_page_ != last_page_;

}

NewSpacePage* NewSpacePageIterator::next() {

  ASSERT(has_next());

  prev_page_ = next_page_;

  next_page_ = next_page_->next_page();

  return prev_page_;

}

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

// HeapObjectIterator

HeapObject* HeapObjectIterator::FromCurrentPage() {

  while (cur_addr_ != cur_end_) {

    if (cur_addr_ == space_->top() && cur_addr_ != space_->limit()) {

      cur_addr_ = space_->limit();

      continue;

    }

    HeapObject* obj = HeapObject::FromAddress(cur_addr_);

    int obj_size = (size_func_ == NULL) ? obj->Size() : size_func_(obj);

    cur_addr_ += obj_size;

    ASSERT(cur_addr_ <= cur_end_);

    if (!obj->IsFiller()) {

      ASSERT_OBJECT_SIZE(obj_size);

      return obj;

    }

  }

  return NULL;

}

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

// MemoryAllocator

#ifdef ENABLE_HEAP_PROTECTION

void MemoryAllocator::Protect(Address start, size_t size) {

  OS::Protect(start, size);

}

void MemoryAllocator::Unprotect(Address start,

                                size_t size,

                                Executability executable) {

  OS::Unprotect(start, size, executable);

}

void MemoryAllocator::ProtectChunkFromPage(Page* page) {

  int id = GetChunkId(page);

  OS::Protect(chunks_[id].address(), chunks_[id].size());

}

void MemoryAllocator::UnprotectChunkFromPage(Page* page) {

  int id = GetChunkId(page);

  OS::Unprotect(chunks_[id].address(), chunks_[id].size(),

                chunks_[id].owner()->executable() == EXECUTABLE);

}

#endif

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

// PagedSpace

Page* Page::Initialize(Heap* heap,

                       MemoryChunk* chunk,

                       Executability executable,

                       PagedSpace* owner) {

  Page* page = reinterpret_cast<Page*>(chunk);

  ASSERT(page->area_size() <= kNonCodeObjectAreaSize);

  ASSERT(chunk->owner() == owner);

  owner->IncreaseCapacity(page->area_size());

  owner->Free(page->area_start(), page->area_size());

  heap->incremental_marking()->SetOldSpacePageFlags(chunk);

  return page;

}

bool PagedSpace::Contains(Address addr) {

  Page* p = Page::FromAddress(addr);

  if (!p->is_valid()) return false;

  return p->owner() == this;

}

void MemoryChunk::set_scan_on_scavenge(bool scan) {

  if (scan) {

    if (!scan_on_scavenge()) heap_->increment_scan_on_scavenge_pages();

    SetFlag(SCAN_ON_SCAVENGE);

  } else {

    if (scan_on_scavenge()) heap_->decrement_scan_on_scavenge_pages();

    ClearFlag(SCAN_ON_SCAVENGE);

  }

  heap_->incremental_marking()->SetOldSpacePageFlags(this);

}

MemoryChunk* MemoryChunk::FromAnyPointerAddress(Heap* heap, Address addr) {

  MemoryChunk* maybe = reinterpret_cast<MemoryChunk*>(

      OffsetFrom(addr) & ~Page::kPageAlignmentMask);

  if (maybe->owner() != NULL) return maybe;

  LargeObjectIterator iterator(heap->lo_space());

  for (HeapObject* o = iterator.Next(); o != NULL; o = iterator.Next()) {

    // Fixed arrays are the only pointer-containing objects in large object

    // space.

    if (o->IsFixedArray()) {

      MemoryChunk* chunk = MemoryChunk::FromAddress(o->address());

      if (chunk->Contains(addr)) {

        return chunk;

      }

    }

  }

  UNREACHABLE();

  return NULL;

}

void MemoryChunk::UpdateHighWaterMark(Address mark) {

  if (mark == NULL) return;

  // Need to subtract one from the mark because when a chunk is full the

  // top points to the next address after the chunk, which effectively belongs

  // to another chunk. See the comment to Page::FromAllocationTop.

  MemoryChunk* chunk = MemoryChunk::FromAddress(mark - 1);

  int new_mark = static_cast<int>(mark - chunk->address());

  if (new_mark > chunk->high_water_mark_) {

    chunk->high_water_mark_ = new_mark;

  }

}

PointerChunkIterator::PointerChunkIterator(Heap* heap)

    : state_(kOldPointerState),

      old_pointer_iterator_(heap->old_pointer_space()),

      map_iterator_(heap->map_space()),

      lo_iterator_(heap->lo_space()) { }

Page* Page::next_page() {

  ASSERT(next_chunk()->owner() == owner());

  return static_cast<Page*>(next_chunk());

}

Page* Page::prev_page() {

  ASSERT(prev_chunk()->owner() == owner());

  return static_cast<Page*>(prev_chunk());

}

void Page::set_next_page(Page* page) {

  ASSERT(page->owner() == owner());

  set_next_chunk(page);

}

void Page::set_prev_page(Page* page) {

  ASSERT(page->owner() == owner());

  set_prev_chunk(page);

}

// Try linear allocation in the page of alloc_info's allocation top.  Does

// not contain slow case logic (e.g. move to the next page or try free list

// allocation) so it can be used by all the allocation functions and for all

// the paged spaces.

HeapObject* PagedSpace::AllocateLinearly(int size_in_bytes) {

  Address current_top = allocation_info_.top();

  Address new_top = current_top + size_in_bytes;

  if (new_top > allocation_info_.limit()) return NULL;

  allocation_info_.set_top(new_top);

  return HeapObject::FromAddress(current_top);

}

// Raw allocation.

MaybeObject* PagedSpace::AllocateRaw(int size_in_bytes,

                                     AllocationType event) {

  HeapProfiler* profiler = heap()->isolate()->heap_profiler();

  HeapObject* object = AllocateLinearly(size_in_bytes);

  if (object != NULL) {

    if (identity() == CODE_SPACE) {

      SkipList::Update(object->address(), size_in_bytes);

    }

    if (event == NEW_OBJECT && profiler->is_tracking_allocations()) {

      profiler->NewObjectEvent(object->address(), size_in_bytes);

    }

    return object;

  }

  ASSERT(!heap()->linear_allocation() ||

         (anchor_.next_chunk() == &anchor_ &&

          anchor_.prev_chunk() == &anchor_));

  object = free_list_.Allocate(size_in_bytes);

  if (object != NULL) {

    if (identity() == CODE_SPACE) {

      SkipList::Update(object->address(), size_in_bytes);

    }

    if (event == NEW_OBJECT && profiler->is_tracking_allocations()) {

      profiler->NewObjectEvent(object->address(), size_in_bytes);

    }

    return object;

  }

  object = SlowAllocateRaw(size_in_bytes);

  if (object != NULL) {

    if (identity() == CODE_SPACE) {

      SkipList::Update(object->address(), size_in_bytes);

    }

    if (event == NEW_OBJECT && profiler->is_tracking_allocations()) {

      profiler->NewObjectEvent(object->address(), size_in_bytes);

    }

    return object;

  }

  return Failure::RetryAfterGC(identity());

}

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

// NewSpace

MaybeObject* NewSpace::AllocateRaw(int size_in_bytes) {

  Address old_top = allocation_info_.top();

#ifdef DEBUG

  // If we are stressing compaction we waste some memory in new space

  // in order to get more frequent GCs.

  if (FLAG_stress_compaction && !heap()->linear_allocation()) {

    if (allocation_info_.limit() - old_top >= size_in_bytes * 4) {

      int filler_size = size_in_bytes * 4;

      for (int i = 0; i < filler_size; i += kPointerSize) {

        *(reinterpret_cast<Object**>(old_top + i)) =

            heap()->one_pointer_filler_map();

      }

      old_top += filler_size;

      allocation_info_.set_top(allocation_info_.top() + filler_size);

    }

  }

#endif

  if (allocation_info_.limit() - old_top < size_in_bytes) {

    return SlowAllocateRaw(size_in_bytes);

  }

  HeapObject* obj = HeapObject::FromAddress(old_top);

  allocation_info_.set_top(allocation_info_.top() + size_in_bytes);

  ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);

  HeapProfiler* profiler = heap()->isolate()->heap_profiler();

  if (profiler != NULL && profiler->is_tracking_allocations()) {

    profiler->NewObjectEvent(obj->address(), size_in_bytes);

  }

  return obj;

}

LargePage* LargePage::Initialize(Heap* heap, MemoryChunk* chunk) {

  heap->incremental_marking()->SetOldSpacePageFlags(chunk);

  return static_cast<LargePage*>(chunk);

}

intptr_t LargeObjectSpace::Available() {

  return ObjectSizeFor(heap()->isolate()->memory_allocator()->Available());

}

bool FreeListNode::IsFreeListNode(HeapObject* object) {

  Map* map = object->map();

  Heap* heap = object->GetHeap();

  return map == heap->raw_unchecked_free_space_map()

      || map == heap->raw_unchecked_one_pointer_filler_map()

      || map == heap->raw_unchecked_two_pointer_filler_map();

}

} }  // namespace v8::internal

#endif  // V8_SPACES_INL_H_