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524 lines
15 KiB
524 lines
15 KiB
// Copyright 2006-2010 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef V8_SPACES_INL_H_
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#define V8_SPACES_INL_H_
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#include "memory.h"
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#include "spaces.h"
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namespace v8 {
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namespace internal {
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// -----------------------------------------------------------------------------
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// PageIterator
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bool PageIterator::has_next() {
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return prev_page_ != stop_page_;
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}
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Page* PageIterator::next() {
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ASSERT(has_next());
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prev_page_ = (prev_page_ == NULL)
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? space_->first_page_
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: prev_page_->next_page();
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return prev_page_;
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}
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// -----------------------------------------------------------------------------
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// Page
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Page* Page::next_page() {
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return MemoryAllocator::GetNextPage(this);
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}
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Address Page::AllocationTop() {
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PagedSpace* owner = MemoryAllocator::PageOwner(this);
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return owner->PageAllocationTop(this);
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}
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Address Page::AllocationWatermark() {
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PagedSpace* owner = MemoryAllocator::PageOwner(this);
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if (this == owner->AllocationTopPage()) {
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return owner->top();
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}
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return address() + AllocationWatermarkOffset();
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}
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uint32_t Page::AllocationWatermarkOffset() {
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return static_cast<uint32_t>((flags_ & kAllocationWatermarkOffsetMask) >>
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kAllocationWatermarkOffsetShift);
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}
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void Page::SetAllocationWatermark(Address allocation_watermark) {
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if ((Heap::gc_state() == Heap::SCAVENGE) && IsWatermarkValid()) {
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// When iterating intergenerational references during scavenge
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// we might decide to promote an encountered young object.
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// We will allocate a space for such an object and put it
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// into the promotion queue to process it later.
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// If space for object was allocated somewhere beyond allocation
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// watermark this might cause garbage pointers to appear under allocation
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// watermark. To avoid visiting them during dirty regions iteration
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// which might be still in progress we store a valid allocation watermark
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// value and mark this page as having an invalid watermark.
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SetCachedAllocationWatermark(AllocationWatermark());
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InvalidateWatermark(true);
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}
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flags_ = (flags_ & kFlagsMask) |
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Offset(allocation_watermark) << kAllocationWatermarkOffsetShift;
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ASSERT(AllocationWatermarkOffset()
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== static_cast<uint32_t>(Offset(allocation_watermark)));
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}
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void Page::SetCachedAllocationWatermark(Address allocation_watermark) {
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mc_first_forwarded = allocation_watermark;
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}
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Address Page::CachedAllocationWatermark() {
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return mc_first_forwarded;
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}
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uint32_t Page::GetRegionMarks() {
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return dirty_regions_;
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}
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void Page::SetRegionMarks(uint32_t marks) {
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dirty_regions_ = marks;
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}
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int Page::GetRegionNumberForAddress(Address addr) {
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// Each page is divided into 256 byte regions. Each region has a corresponding
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// dirty mark bit in the page header. Region can contain intergenerational
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// references iff its dirty mark is set.
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// A normal 8K page contains exactly 32 regions so all region marks fit
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// into 32-bit integer field. To calculate a region number we just divide
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// offset inside page by region size.
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// A large page can contain more then 32 regions. But we want to avoid
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// additional write barrier code for distinguishing between large and normal
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// pages so we just ignore the fact that addr points into a large page and
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// calculate region number as if addr pointed into a normal 8K page. This way
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// we get a region number modulo 32 so for large pages several regions might
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// be mapped to a single dirty mark.
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ASSERT_PAGE_ALIGNED(this->address());
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STATIC_ASSERT((kPageAlignmentMask >> kRegionSizeLog2) < kBitsPerInt);
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// We are using masking with kPageAlignmentMask instead of Page::Offset()
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// to get an offset to the beginning of 8K page containing addr not to the
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// beginning of actual page which can be bigger then 8K.
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intptr_t offset_inside_normal_page = OffsetFrom(addr) & kPageAlignmentMask;
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return static_cast<int>(offset_inside_normal_page >> kRegionSizeLog2);
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}
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uint32_t Page::GetRegionMaskForAddress(Address addr) {
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return 1 << GetRegionNumberForAddress(addr);
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}
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uint32_t Page::GetRegionMaskForSpan(Address start, int length_in_bytes) {
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uint32_t result = 0;
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if (length_in_bytes >= kPageSize) {
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result = kAllRegionsDirtyMarks;
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} else if (length_in_bytes > 0) {
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int start_region = GetRegionNumberForAddress(start);
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int end_region =
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GetRegionNumberForAddress(start + length_in_bytes - kPointerSize);
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uint32_t start_mask = (~0) << start_region;
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uint32_t end_mask = ~((~1) << end_region);
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result = start_mask & end_mask;
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// if end_region < start_region, the mask is ored.
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if (result == 0) result = start_mask | end_mask;
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}
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#ifdef DEBUG
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if (FLAG_enable_slow_asserts) {
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uint32_t expected = 0;
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for (Address a = start; a < start + length_in_bytes; a += kPointerSize) {
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expected |= GetRegionMaskForAddress(a);
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}
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ASSERT(expected == result);
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}
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#endif
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return result;
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}
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void Page::MarkRegionDirty(Address address) {
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SetRegionMarks(GetRegionMarks() | GetRegionMaskForAddress(address));
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}
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bool Page::IsRegionDirty(Address address) {
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return GetRegionMarks() & GetRegionMaskForAddress(address);
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}
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void Page::ClearRegionMarks(Address start, Address end, bool reaches_limit) {
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int rstart = GetRegionNumberForAddress(start);
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int rend = GetRegionNumberForAddress(end);
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if (reaches_limit) {
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end += 1;
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}
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if ((rend - rstart) == 0) {
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return;
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}
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uint32_t bitmask = 0;
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if ((OffsetFrom(start) & kRegionAlignmentMask) == 0
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|| (start == ObjectAreaStart())) {
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// First region is fully covered
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bitmask = 1 << rstart;
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}
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while (++rstart < rend) {
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bitmask |= 1 << rstart;
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}
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if (bitmask) {
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SetRegionMarks(GetRegionMarks() & ~bitmask);
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}
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}
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void Page::FlipMeaningOfInvalidatedWatermarkFlag() {
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watermark_invalidated_mark_ ^= 1 << WATERMARK_INVALIDATED;
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}
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bool Page::IsWatermarkValid() {
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return (flags_ & (1 << WATERMARK_INVALIDATED)) != watermark_invalidated_mark_;
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}
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void Page::InvalidateWatermark(bool value) {
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if (value) {
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flags_ = (flags_ & ~(1 << WATERMARK_INVALIDATED)) |
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watermark_invalidated_mark_;
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} else {
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flags_ = (flags_ & ~(1 << WATERMARK_INVALIDATED)) |
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(watermark_invalidated_mark_ ^ (1 << WATERMARK_INVALIDATED));
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}
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ASSERT(IsWatermarkValid() == !value);
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}
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bool Page::GetPageFlag(PageFlag flag) {
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return (flags_ & static_cast<intptr_t>(1 << flag)) != 0;
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}
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void Page::SetPageFlag(PageFlag flag, bool value) {
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if (value) {
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flags_ |= static_cast<intptr_t>(1 << flag);
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} else {
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flags_ &= ~static_cast<intptr_t>(1 << flag);
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}
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}
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void Page::ClearPageFlags() {
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flags_ = 0;
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}
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void Page::ClearGCFields() {
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InvalidateWatermark(true);
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SetAllocationWatermark(ObjectAreaStart());
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if (Heap::gc_state() == Heap::SCAVENGE) {
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SetCachedAllocationWatermark(ObjectAreaStart());
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}
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SetRegionMarks(kAllRegionsCleanMarks);
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}
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bool Page::WasInUseBeforeMC() {
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return GetPageFlag(WAS_IN_USE_BEFORE_MC);
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}
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void Page::SetWasInUseBeforeMC(bool was_in_use) {
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SetPageFlag(WAS_IN_USE_BEFORE_MC, was_in_use);
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}
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bool Page::IsLargeObjectPage() {
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return !GetPageFlag(IS_NORMAL_PAGE);
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}
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void Page::SetIsLargeObjectPage(bool is_large_object_page) {
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SetPageFlag(IS_NORMAL_PAGE, !is_large_object_page);
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}
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bool Page::IsPageExecutable() {
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return GetPageFlag(IS_EXECUTABLE);
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}
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void Page::SetIsPageExecutable(bool is_page_executable) {
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SetPageFlag(IS_EXECUTABLE, is_page_executable);
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}
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// -----------------------------------------------------------------------------
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// MemoryAllocator
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void MemoryAllocator::ChunkInfo::init(Address a, size_t s, PagedSpace* o) {
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address_ = a;
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size_ = s;
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owner_ = o;
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executable_ = (o == NULL) ? NOT_EXECUTABLE : o->executable();
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}
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bool MemoryAllocator::IsValidChunk(int chunk_id) {
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if (!IsValidChunkId(chunk_id)) return false;
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ChunkInfo& c = chunks_[chunk_id];
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return (c.address() != NULL) && (c.size() != 0) && (c.owner() != NULL);
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}
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bool MemoryAllocator::IsValidChunkId(int chunk_id) {
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return (0 <= chunk_id) && (chunk_id < max_nof_chunks_);
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}
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bool MemoryAllocator::IsPageInSpace(Page* p, PagedSpace* space) {
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ASSERT(p->is_valid());
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int chunk_id = GetChunkId(p);
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if (!IsValidChunkId(chunk_id)) return false;
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ChunkInfo& c = chunks_[chunk_id];
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return (c.address() <= p->address()) &&
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(p->address() < c.address() + c.size()) &&
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(space == c.owner());
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}
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Page* MemoryAllocator::GetNextPage(Page* p) {
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ASSERT(p->is_valid());
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intptr_t raw_addr = p->opaque_header & ~Page::kPageAlignmentMask;
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return Page::FromAddress(AddressFrom<Address>(raw_addr));
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}
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int MemoryAllocator::GetChunkId(Page* p) {
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ASSERT(p->is_valid());
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return static_cast<int>(p->opaque_header & Page::kPageAlignmentMask);
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}
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void MemoryAllocator::SetNextPage(Page* prev, Page* next) {
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ASSERT(prev->is_valid());
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int chunk_id = GetChunkId(prev);
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ASSERT_PAGE_ALIGNED(next->address());
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prev->opaque_header = OffsetFrom(next->address()) | chunk_id;
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}
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PagedSpace* MemoryAllocator::PageOwner(Page* page) {
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int chunk_id = GetChunkId(page);
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ASSERT(IsValidChunk(chunk_id));
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return chunks_[chunk_id].owner();
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}
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bool MemoryAllocator::InInitialChunk(Address address) {
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if (initial_chunk_ == NULL) return false;
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Address start = static_cast<Address>(initial_chunk_->address());
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return (start <= address) && (address < start + initial_chunk_->size());
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}
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#ifdef ENABLE_HEAP_PROTECTION
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void MemoryAllocator::Protect(Address start, size_t size) {
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OS::Protect(start, size);
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}
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void MemoryAllocator::Unprotect(Address start,
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size_t size,
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Executability executable) {
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OS::Unprotect(start, size, executable);
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}
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void MemoryAllocator::ProtectChunkFromPage(Page* page) {
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int id = GetChunkId(page);
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OS::Protect(chunks_[id].address(), chunks_[id].size());
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}
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void MemoryAllocator::UnprotectChunkFromPage(Page* page) {
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int id = GetChunkId(page);
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OS::Unprotect(chunks_[id].address(), chunks_[id].size(),
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chunks_[id].owner()->executable() == EXECUTABLE);
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}
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#endif
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// --------------------------------------------------------------------------
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// PagedSpace
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bool PagedSpace::Contains(Address addr) {
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Page* p = Page::FromAddress(addr);
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if (!p->is_valid()) return false;
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return MemoryAllocator::IsPageInSpace(p, this);
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}
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bool PagedSpace::SafeContains(Address addr) {
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if (!MemoryAllocator::SafeIsInAPageChunk(addr)) return false;
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Page* p = Page::FromAddress(addr);
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if (!p->is_valid()) return false;
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return MemoryAllocator::IsPageInSpace(p, this);
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}
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// Try linear allocation in the page of alloc_info's allocation top. Does
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// not contain slow case logic (eg, move to the next page or try free list
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// allocation) so it can be used by all the allocation functions and for all
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// the paged spaces.
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HeapObject* PagedSpace::AllocateLinearly(AllocationInfo* alloc_info,
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int size_in_bytes) {
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Address current_top = alloc_info->top;
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Address new_top = current_top + size_in_bytes;
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if (new_top > alloc_info->limit) return NULL;
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alloc_info->top = new_top;
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ASSERT(alloc_info->VerifyPagedAllocation());
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accounting_stats_.AllocateBytes(size_in_bytes);
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return HeapObject::FromAddress(current_top);
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}
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// Raw allocation.
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MaybeObject* PagedSpace::AllocateRaw(int size_in_bytes) {
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ASSERT(HasBeenSetup());
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ASSERT_OBJECT_SIZE(size_in_bytes);
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HeapObject* object = AllocateLinearly(&allocation_info_, size_in_bytes);
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if (object != NULL) return object;
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object = SlowAllocateRaw(size_in_bytes);
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if (object != NULL) return object;
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return Failure::RetryAfterGC(identity());
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}
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// Reallocating (and promoting) objects during a compacting collection.
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MaybeObject* PagedSpace::MCAllocateRaw(int size_in_bytes) {
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ASSERT(HasBeenSetup());
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ASSERT_OBJECT_SIZE(size_in_bytes);
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HeapObject* object = AllocateLinearly(&mc_forwarding_info_, size_in_bytes);
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if (object != NULL) return object;
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object = SlowMCAllocateRaw(size_in_bytes);
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if (object != NULL) return object;
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return Failure::RetryAfterGC(identity());
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}
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// -----------------------------------------------------------------------------
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// LargeObjectChunk
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Address LargeObjectChunk::GetStartAddress() {
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// Round the chunk address up to the nearest page-aligned address
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// and return the heap object in that page.
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Page* page = Page::FromAddress(RoundUp(address(), Page::kPageSize));
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return page->ObjectAreaStart();
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}
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void LargeObjectChunk::Free(Executability executable) {
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MemoryAllocator::FreeRawMemory(address(), size(), executable);
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}
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// -----------------------------------------------------------------------------
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// NewSpace
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MaybeObject* NewSpace::AllocateRawInternal(int size_in_bytes,
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AllocationInfo* alloc_info) {
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Address new_top = alloc_info->top + size_in_bytes;
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if (new_top > alloc_info->limit) return Failure::RetryAfterGC();
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Object* obj = HeapObject::FromAddress(alloc_info->top);
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alloc_info->top = new_top;
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#ifdef DEBUG
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SemiSpace* space =
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(alloc_info == &allocation_info_) ? &to_space_ : &from_space_;
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ASSERT(space->low() <= alloc_info->top
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&& alloc_info->top <= space->high()
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&& alloc_info->limit == space->high());
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#endif
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return obj;
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}
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template <typename StringType>
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void NewSpace::ShrinkStringAtAllocationBoundary(String* string, int length) {
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ASSERT(length <= string->length());
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ASSERT(string->IsSeqString());
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ASSERT(string->address() + StringType::SizeFor(string->length()) ==
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allocation_info_.top);
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allocation_info_.top =
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string->address() + StringType::SizeFor(length);
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string->set_length(length);
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}
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bool FreeListNode::IsFreeListNode(HeapObject* object) {
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return object->map() == Heap::raw_unchecked_byte_array_map()
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|| object->map() == Heap::raw_unchecked_one_pointer_filler_map()
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|| object->map() == Heap::raw_unchecked_two_pointer_filler_map();
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}
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} } // namespace v8::internal
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#endif // V8_SPACES_INL_H_
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