/* * Copyright (C) 2017 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 "MarkedBlock.h" #include <wtf/Bitmap.h> #include <wtf/ConcurrentVector.h> #include <wtf/FastBitVector.h> #include <wtf/SentinelLinkedList.h> #include <wtf/SharedTask.h> namespace JSC { class HeapCell; class IsoSubspace; // Create a set of cells that are in an IsoSubspace. This allows concurrent O(1) set insertion and // removal. Each such set should be thought of as a 0.8% increase in object size for objects in that // IsoSubspace (it's like adding 1 bit every 16 bytes, or 1 bit every 128 bits). class IsoCellSet : public BasicRawSentinelNode<IsoCellSet> { public: IsoCellSet(IsoSubspace& subspace); ~IsoCellSet(); bool add(HeapCell* cell); // Returns true if the cell was newly added. bool remove(HeapCell* cell); // Returns true if the cell was previously present and got removed. bool contains(HeapCell* cell) const; JS_EXPORT_PRIVATE RefPtr<SharedTask<MarkedBlock::Handle*()>> parallelNotEmptyMarkedBlockSource(); // This will have to do a combined search over whatever Subspace::forEachMarkedCell uses and // our m_blocksWithBits. template<typename Func> void forEachMarkedCell(const Func&); template<typename Func> RefPtr<SharedTask<void(SlotVisitor&)>> forEachMarkedCellInParallel(const Func&); template<typename Func> void forEachLiveCell(const Func&); private: friend class IsoSubspace; Bitmap<MarkedBlock::atomsPerBlock>* addSlow(size_t blockIndex); void didResizeBits(size_t newSize); void didRemoveBlock(size_t blockIndex); void sweepToFreeList(MarkedBlock::Handle*); IsoSubspace& m_subspace; // Idea: sweeping to free-list clears bits for those cells that were free-listed. The first time // we add a cell in a block, that block gets a free-list. Unless we do something that obviously // clears all bits for a block, we keep it set in blocksWithBits. FastBitVector m_blocksWithBits; ConcurrentVector<std::unique_ptr<Bitmap<MarkedBlock::atomsPerBlock>>> m_bits; }; } // namespace JSC