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Diffstat (limited to 'JavaScriptCore/kjs/collector.h')
-rw-r--r-- | JavaScriptCore/kjs/collector.h | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/JavaScriptCore/kjs/collector.h b/JavaScriptCore/kjs/collector.h new file mode 100644 index 0000000..4233b06 --- /dev/null +++ b/JavaScriptCore/kjs/collector.h @@ -0,0 +1,279 @@ +/* + * Copyright (C) 1999-2000 Harri Porten (porten@kde.org) + * Copyright (C) 2001 Peter Kelly (pmk@post.com) + * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#ifndef KJSCOLLECTOR_H_ +#define KJSCOLLECTOR_H_ + +#include "JSImmediate.h" +#include <string.h> +#include <wtf/HashCountedSet.h> +#include <wtf/HashSet.h> +#include <wtf/Noncopyable.h> +#include <wtf/OwnPtr.h> +#include <wtf/Threading.h> + +// This is supremely lame that we require pthreads to build on windows. +#if ENABLE(JSC_MULTIPLE_THREADS) +#include <pthread.h> +#endif + +#define ASSERT_CLASS_FITS_IN_CELL(class) COMPILE_ASSERT(sizeof(class) <= CELL_SIZE, class_fits_in_cell) + +namespace JSC { + + class ArgList; + class CollectorBlock; + class JSCell; + class JSGlobalData; + + enum OperationInProgress { NoOperation, Allocation, Collection }; + enum HeapType { PrimaryHeap, NumberHeap }; + + template <HeapType> class CollectorHeapIterator; + + struct CollectorHeap { + CollectorBlock** blocks; + size_t numBlocks; + size_t usedBlocks; + size_t firstBlockWithPossibleSpace; + + size_t numLiveObjects; + size_t numLiveObjectsAtLastCollect; + size_t extraCost; + + OperationInProgress operationInProgress; + }; + + class Heap : Noncopyable { + public: + class Thread; + typedef CollectorHeapIterator<PrimaryHeap> iterator; + + void destroy(); + +#ifdef JAVASCRIPTCORE_BUILDING_ALL_IN_ONE_FILE + // We can inline these functions because everything is compiled as + // one file, so the heapAllocate template definitions are available. + // However, allocateNumber is used via jsNumberCell outside JavaScriptCore. + // Thus allocateNumber needs to provide a non-inline version too. + void* inlineAllocateNumber(size_t s) { return heapAllocate<NumberHeap>(s); } + void* inlineAllocate(size_t s) { return heapAllocate<PrimaryHeap>(s); } +#endif + void* allocateNumber(size_t); + void* allocate(size_t); + + bool collect(); + bool isBusy(); // true if an allocation or collection is in progress + + static const size_t minExtraCostSize = 256; + + void reportExtraMemoryCost(size_t cost); + + size_t size(); + + void setGCProtectNeedsLocking(); + void protect(JSValue*); + void unprotect(JSValue*); + + static Heap* heap(JSValue*); // 0 for immediate values + + size_t globalObjectCount(); + size_t protectedObjectCount(); + size_t protectedGlobalObjectCount(); + HashCountedSet<const char*>* protectedObjectTypeCounts(); + + void registerThread(); // Only needs to be called by clients that can use the same heap from multiple threads. + + static bool isCellMarked(const JSCell*); + static void markCell(JSCell*); + + void markConservatively(void* start, void* end); + + HashSet<ArgList*>& markListSet() { if (!m_markListSet) m_markListSet = new HashSet<ArgList*>; return *m_markListSet; } + + JSGlobalData* globalData() const { return m_globalData; } + static bool isNumber(JSCell*); + + // Iterators for the object heap. + iterator primaryHeapBegin(); + iterator primaryHeapEnd(); + + private: + template <HeapType heapType> void* heapAllocate(size_t); + template <HeapType heapType> size_t sweep(); + static CollectorBlock* cellBlock(const JSCell*); + static size_t cellOffset(const JSCell*); + + friend class JSGlobalData; + Heap(JSGlobalData*); + ~Heap(); + + void recordExtraCost(size_t); + void markProtectedObjects(); + void markCurrentThreadConservatively(); + void markCurrentThreadConservativelyInternal(); + void markOtherThreadConservatively(Thread*); + void markStackObjectsConservatively(); + + typedef HashCountedSet<JSCell*> ProtectCountSet; + + CollectorHeap primaryHeap; + CollectorHeap numberHeap; + + OwnPtr<Mutex> m_protectedValuesMutex; // Only non-null if the client explicitly requested it via setGCPrtotectNeedsLocking(). + ProtectCountSet m_protectedValues; + + HashSet<ArgList*>* m_markListSet; + +#if ENABLE(JSC_MULTIPLE_THREADS) + static void unregisterThread(void*); + void unregisterThread(); + + Mutex m_registeredThreadsMutex; + Thread* m_registeredThreads; + pthread_key_t m_currentThreadRegistrar; +#endif + + JSGlobalData* m_globalData; + }; + + // tunable parameters + template<size_t bytesPerWord> struct CellSize; + + // cell size needs to be a power of two for certain optimizations in collector.cpp + template<> struct CellSize<sizeof(uint32_t)> { static const size_t m_value = 32; }; // 32-bit + template<> struct CellSize<sizeof(uint64_t)> { static const size_t m_value = 64; }; // 64-bit + const size_t BLOCK_SIZE = 16 * 4096; // 64k + + // derived constants + const size_t BLOCK_OFFSET_MASK = BLOCK_SIZE - 1; + const size_t BLOCK_MASK = ~BLOCK_OFFSET_MASK; + const size_t MINIMUM_CELL_SIZE = CellSize<sizeof(void*)>::m_value; + const size_t CELL_ARRAY_LENGTH = (MINIMUM_CELL_SIZE / sizeof(double)) + (MINIMUM_CELL_SIZE % sizeof(double) != 0 ? sizeof(double) : 0); + const size_t CELL_SIZE = CELL_ARRAY_LENGTH * sizeof(double); + const size_t SMALL_CELL_SIZE = CELL_SIZE / 2; + const size_t CELL_MASK = CELL_SIZE - 1; + const size_t CELL_ALIGN_MASK = ~CELL_MASK; + const size_t CELLS_PER_BLOCK = (BLOCK_SIZE * 8 - sizeof(uint32_t) * 8 - sizeof(void *) * 8 - 2 * (7 + 3 * 8)) / (CELL_SIZE * 8 + 2); + const size_t SMALL_CELLS_PER_BLOCK = 2 * CELLS_PER_BLOCK; + const size_t BITMAP_SIZE = (CELLS_PER_BLOCK + 7) / 8; + const size_t BITMAP_WORDS = (BITMAP_SIZE + 3) / sizeof(uint32_t); + + struct CollectorBitmap { + uint32_t bits[BITMAP_WORDS]; + bool get(size_t n) const { return !!(bits[n >> 5] & (1 << (n & 0x1F))); } + void set(size_t n) { bits[n >> 5] |= (1 << (n & 0x1F)); } + void clear(size_t n) { bits[n >> 5] &= ~(1 << (n & 0x1F)); } + void clearAll() { memset(bits, 0, sizeof(bits)); } + }; + + struct CollectorCell { + union { + double memory[CELL_ARRAY_LENGTH]; + struct { + void* zeroIfFree; + ptrdiff_t next; + } freeCell; + } u; + }; + + struct SmallCollectorCell { + union { + double memory[CELL_ARRAY_LENGTH / 2]; + struct { + void* zeroIfFree; + ptrdiff_t next; + } freeCell; + } u; + }; + + class CollectorBlock { + public: + CollectorCell cells[CELLS_PER_BLOCK]; + uint32_t usedCells; + CollectorCell* freeList; + CollectorBitmap marked; + Heap* heap; + HeapType type; + }; + + class SmallCellCollectorBlock { + public: + SmallCollectorCell cells[SMALL_CELLS_PER_BLOCK]; + uint32_t usedCells; + SmallCollectorCell* freeList; + CollectorBitmap marked; + Heap* heap; + HeapType type; + }; + + template <HeapType heapType> struct HeapConstants; + + template <> struct HeapConstants<PrimaryHeap> { + static const size_t cellSize = CELL_SIZE; + static const size_t cellsPerBlock = CELLS_PER_BLOCK; + static const size_t bitmapShift = 0; + typedef CollectorCell Cell; + typedef CollectorBlock Block; + }; + + template <> struct HeapConstants<NumberHeap> { + static const size_t cellSize = SMALL_CELL_SIZE; + static const size_t cellsPerBlock = SMALL_CELLS_PER_BLOCK; + static const size_t bitmapShift = 1; + typedef SmallCollectorCell Cell; + typedef SmallCellCollectorBlock Block; + }; + + inline CollectorBlock* Heap::cellBlock(const JSCell* cell) + { + return reinterpret_cast<CollectorBlock*>(reinterpret_cast<uintptr_t>(cell) & BLOCK_MASK); + } + + inline bool Heap::isNumber(JSCell* cell) + { + return Heap::cellBlock(cell)->type == NumberHeap; + } + + inline size_t Heap::cellOffset(const JSCell* cell) + { + return (reinterpret_cast<uintptr_t>(cell) & BLOCK_OFFSET_MASK) / CELL_SIZE; + } + + inline bool Heap::isCellMarked(const JSCell* cell) + { + return cellBlock(cell)->marked.get(cellOffset(cell)); + } + + inline void Heap::markCell(JSCell* cell) + { + cellBlock(cell)->marked.set(cellOffset(cell)); + } + + inline void Heap::reportExtraMemoryCost(size_t cost) + { + if (cost > minExtraCostSize) + recordExtraCost(cost / (CELL_SIZE * 2)); + } + +} // namespace JSC + +#endif /* KJSCOLLECTOR_H_ */ |