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/*
* Copyright (C) 2012-2021 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 "AllocationFailureMode.h"
#include "BlockDirectoryBits.h"
#include "CellAttributes.h"
#include "FreeList.h"
#include "LocalAllocator.h"
#include "MarkedBlock.h"
#include <wtf/DataLog.h>
#include <wtf/FastBitVector.h>
#include <wtf/MonotonicTime.h>
#include <wtf/SharedTask.h>
#include <wtf/Vector.h>
namespace WTF {
class SimpleStats;
}
namespace JSC {
class GCDeferralContext;
class Heap;
class IsoCellSet;
class MarkedSpace;
class LLIntOffsetsExtractor;
DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(BlockDirectory);
class BlockDirectory {
WTF_MAKE_NONCOPYABLE(BlockDirectory);
WTF_MAKE_FAST_ALLOCATED_WITH_HEAP_IDENTIFIER(BlockDirectory);
friend class LLIntOffsetsExtractor;
public:
BlockDirectory(size_t cellSize);
~BlockDirectory();
void setSubspace(Subspace*);
void lastChanceToFinalize();
void prepareForAllocation();
void stopAllocating();
void stopAllocatingForGood();
void resumeAllocating();
void beginMarkingForFullCollection();
void endMarking();
void snapshotUnsweptForEdenCollection();
void snapshotUnsweptForFullCollection();
void sweep();
void shrink();
void assertNoUnswept();
size_t cellSize() const { return m_cellSize; }
CellAttributes attributes() const { return m_attributes; }
bool needsDestruction() const { return m_attributes.destruction == NeedsDestruction; }
DestructionMode destruction() const { return m_attributes.destruction; }
HeapCell::Kind cellKind() const { return m_attributes.cellKind; }
bool isFreeListedCell(const void* target);
template<typename Functor> void forEachBlock(const Functor&);
template<typename Functor> void forEachNotEmptyBlock(const Functor&);
RefPtr<SharedTask<MarkedBlock::Handle*()>> parallelNotEmptyBlockSource();
void addBlock(MarkedBlock::Handle*);
enum class WillDeleteBlock : bool { No, Yes };
// If WillDeleteBlock::Yes is passed then the block will be left in an invalid state. We do this, however, to avoid potentially paging in / decompressing old blocks to update their handle just before freeing them.
void removeBlock(MarkedBlock::Handle*, WillDeleteBlock = WillDeleteBlock::No);
void updatePercentageOfPagedOutPages(WTF::SimpleStats&);
Lock& bitvectorLock() WTF_RETURNS_LOCK(m_bitvectorLock) { return m_bitvectorLock; }
#define BLOCK_DIRECTORY_BIT_ACCESSORS(lowerBitName, capitalBitName) \
bool is ## capitalBitName(const AbstractLocker&, size_t index) const { return m_bits.is ## capitalBitName(index); } \
bool is ## capitalBitName(const AbstractLocker& locker, MarkedBlock::Handle* block) const { return is ## capitalBitName(locker, block->index()); } \
void setIs ## capitalBitName(const AbstractLocker&, size_t index, bool value) { m_bits.setIs ## capitalBitName(index, value); } \
void setIs ## capitalBitName(const AbstractLocker& locker, MarkedBlock::Handle* block, bool value) { setIs ## capitalBitName(locker, block->index(), value); }
FOR_EACH_BLOCK_DIRECTORY_BIT(BLOCK_DIRECTORY_BIT_ACCESSORS)
#undef BLOCK_DIRECTORY_BIT_ACCESSORS
template<typename Func>
void forEachBitVector(const AbstractLocker&, const Func& func)
{
#define BLOCK_DIRECTORY_BIT_CALLBACK(lowerBitName, capitalBitName) \
func(m_bits.lowerBitName());
FOR_EACH_BLOCK_DIRECTORY_BIT(BLOCK_DIRECTORY_BIT_CALLBACK);
#undef BLOCK_DIRECTORY_BIT_CALLBACK
}
template<typename Func>
void forEachBitVectorWithName(const AbstractLocker&, const Func& func)
{
#define BLOCK_DIRECTORY_BIT_CALLBACK(lowerBitName, capitalBitName) \
func(m_bits.lowerBitName(), #capitalBitName);
FOR_EACH_BLOCK_DIRECTORY_BIT(BLOCK_DIRECTORY_BIT_CALLBACK);
#undef BLOCK_DIRECTORY_BIT_CALLBACK
}
BlockDirectory* nextDirectory() const { return m_nextDirectory; }
BlockDirectory* nextDirectoryInSubspace() const { return m_nextDirectoryInSubspace; }
BlockDirectory* nextDirectoryInAlignedMemoryAllocator() const { return m_nextDirectoryInAlignedMemoryAllocator; }
void setNextDirectory(BlockDirectory* directory) { m_nextDirectory = directory; }
void setNextDirectoryInSubspace(BlockDirectory* directory) { m_nextDirectoryInSubspace = directory; }
void setNextDirectoryInAlignedMemoryAllocator(BlockDirectory* directory) { m_nextDirectoryInAlignedMemoryAllocator = directory; }
MarkedBlock::Handle* findEmptyBlockToSteal();
MarkedBlock::Handle* findBlockToSweep();
Subspace* subspace() const { return m_subspace; }
MarkedSpace& markedSpace() const;
void dump(PrintStream&) const;
void dumpBits(PrintStream& = WTF::dataFile());
private:
friend class IsoCellSet;
friend class LocalAllocator;
friend class LocalSideAllocator;
friend class MarkedBlock;
MarkedBlock::Handle* findBlockForAllocation(LocalAllocator&);
MarkedBlock::Handle* tryAllocateBlock(Heap&);
Vector<MarkedBlock::Handle*> m_blocks;
Vector<unsigned> m_freeBlockIndices;
// Mutator uses this to guard resizing the bitvectors. Those things in the GC that may run
// concurrently to the mutator must lock this when accessing the bitvectors.
BlockDirectoryBits m_bits;
Lock m_bitvectorLock;
Lock m_localAllocatorsLock;
CellAttributes m_attributes;
unsigned m_cellSize;
// After you do something to a block based on one of these cursors, you clear the bit in the
// corresponding bitvector and leave the cursor where it was. We can use unsigned instead of size_t since
// this number is bound by capacity of Vector m_blocks, which must be within unsigned.
unsigned m_emptyCursor { 0 };
unsigned m_unsweptCursor { 0 }; // Points to the next block that is a candidate for incremental sweeping.
// FIXME: All of these should probably be references.
// https://bugs.webkit.org/show_bug.cgi?id=166988
Subspace* m_subspace { nullptr };
BlockDirectory* m_nextDirectory { nullptr };
BlockDirectory* m_nextDirectoryInSubspace { nullptr };
BlockDirectory* m_nextDirectoryInAlignedMemoryAllocator { nullptr };
SentinelLinkedList<LocalAllocator, BasicRawSentinelNode<LocalAllocator>> m_localAllocators;
};
} // namespace JSC
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