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/*
* Copyright (C) 2016-2019 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. ``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
* 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.
*/
#pragma once
#include <wtf/StdLibExtras.h>
namespace JSC {
class Heap;
class HeapCell;
class PreciseAllocation;
class MarkedBlock;
class WeakSet;
class VM;
typedef uint32_t HeapVersion;
// This is how we abstract over either MarkedBlock& or PreciseAllocation&. Put things in here as you
// find need for them.
class CellContainer {
public:
CellContainer()
: m_encodedPointer(0)
{
}
CellContainer(MarkedBlock& markedBlock)
: m_encodedPointer(bitwise_cast<uintptr_t>(&markedBlock))
{
}
CellContainer(PreciseAllocation& preciseAllocation)
: m_encodedPointer(bitwise_cast<uintptr_t>(&preciseAllocation) | isPreciseAllocationBit)
{
}
VM& vm() const;
JSC::Heap* heap() const;
explicit operator bool() const { return !!m_encodedPointer; }
bool isMarkedBlock() const { return m_encodedPointer && !(m_encodedPointer & isPreciseAllocationBit); }
bool isPreciseAllocation() const { return m_encodedPointer & isPreciseAllocationBit; }
MarkedBlock& markedBlock() const
{
ASSERT(isMarkedBlock());
return *bitwise_cast<MarkedBlock*>(m_encodedPointer);
}
PreciseAllocation& preciseAllocation() const
{
ASSERT(isPreciseAllocation());
return *bitwise_cast<PreciseAllocation*>(m_encodedPointer - isPreciseAllocationBit);
}
void aboutToMark(HeapVersion markingVersion);
bool areMarksStale() const;
bool isMarked(HeapCell*) const;
bool isMarked(HeapVersion markingVersion, HeapCell*) const;
bool isNewlyAllocated(HeapCell*) const;
void noteMarked();
void assertValidCell(VM&, HeapCell*) const;
size_t cellSize() const;
WeakSet& weakSet() const;
private:
static constexpr uintptr_t isPreciseAllocationBit = 1;
uintptr_t m_encodedPointer;
};
} // namespace JSC
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