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MarkedBlock.cpp
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MarkedBlock.cpp
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/*
* Copyright (C) 2011 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "config.h"
#include "MarkedBlock.h"
#include "JSCell.h"
#include "JSObject.h"
#include "JSZombie.h"
#include "ScopeChain.h"
namespace JSC {
MarkedBlock* MarkedBlock::create(Heap* heap, size_t cellSize)
{
PageAllocationAligned allocation = PageAllocationAligned::allocate(blockSize, blockSize, OSAllocator::JSGCHeapPages);
if (!static_cast<bool>(allocation))
CRASH();
return new (allocation.base()) MarkedBlock(allocation, heap, cellSize);
}
void MarkedBlock::destroy(MarkedBlock* block)
{
for (size_t i = block->firstAtom(); i < block->m_endAtom; i += block->m_atomsPerCell)
reinterpret_cast<JSCell*>(&block->atoms()[i])->~JSCell();
block->m_allocation.deallocate();
}
MarkedBlock::MarkedBlock(const PageAllocationAligned& allocation, Heap* heap, size_t cellSize)
: m_nextAtom(firstAtom())
, m_inNewSpace(false)
, m_allocation(allocation)
, m_heap(heap)
{
m_atomsPerCell = (cellSize + atomSize - 1) / atomSize;
m_endAtom = atomsPerBlock - m_atomsPerCell + 1;
Structure* dummyMarkableCellStructure = heap->globalData()->dummyMarkableCellStructure.get();
for (size_t i = firstAtom(); i < m_endAtom; i += m_atomsPerCell)
new (&atoms()[i]) JSCell(*heap->globalData(), dummyMarkableCellStructure, JSCell::CreatingEarlyCell);
}
void MarkedBlock::sweep()
{
Structure* dummyMarkableCellStructure = m_heap->globalData()->dummyMarkableCellStructure.get();
for (size_t i = firstAtom(); i < m_endAtom; i += m_atomsPerCell) {
if (m_marks.get(i))
continue;
JSCell* cell = reinterpret_cast<JSCell*>(&atoms()[i]);
#if ENABLE(JSC_ZOMBIES)
if (cell->structure() && cell->structure() != dummyMarkableCellStructure && !cell->isZombie()) {
const ClassInfo* info = cell->classInfo();
cell->~JSCell();
new (cell) JSZombie(*m_heap->globalData(), info, m_heap->globalData()->zombieStructure.get());
m_marks.set(i);
}
#else
cell->~JSCell();
new (cell) JSCell(*m_heap->globalData(), dummyMarkableCellStructure);
#endif
}
}
#if ENABLE(JSC_ZOMBIES)
void MarkedBlock::clearMarks()
{
/* Keep our precious zombies! */
for (size_t i = firstAtom(); i < m_endAtom; i += m_atomsPerCell) {
if (m_marks.get(i))
continue;
JSCell* cell = reinterpret_cast<JSCell*>(&atoms()[i]);
if (!cell->isZombie())
m_marks.clear(i);
}
}
#endif
} // namespace JSC