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Diffstat (limited to 'Source/JavaScriptCore/runtime/MarkedBlock.h')
| -rw-r--r-- | Source/JavaScriptCore/runtime/MarkedBlock.h | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/runtime/MarkedBlock.h b/Source/JavaScriptCore/runtime/MarkedBlock.h new file mode 100644 index 0000000..f726c25 --- /dev/null +++ b/Source/JavaScriptCore/runtime/MarkedBlock.h @@ -0,0 +1,177 @@ +/* + * 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, 2009 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 MarkedBlock_h +#define MarkedBlock_h + +#include <wtf/Bitmap.h> +#include <wtf/FixedArray.h> +#include <wtf/PageAllocationAligned.h> + +#define ASSERT_CLASS_FITS_IN_CELL(class) COMPILE_ASSERT(sizeof(class) <= MarkedBlock::CELL_SIZE, class_fits_in_cell) + +namespace JSC { + + class Heap; + class JSCell; + class JSGlobalData; + + class MarkedBlock { +#if OS(WINCE) || OS(SYMBIAN) || PLATFORM(BREWMP) + static const size_t BLOCK_SIZE = 64 * 1024; // 64k +#else + static const size_t BLOCK_SIZE = 256 * 1024; // 256k +#endif + + static const size_t BLOCK_OFFSET_MASK = BLOCK_SIZE - 1; + static const size_t BLOCK_MASK = ~BLOCK_OFFSET_MASK; + static const size_t MINIMUM_CELL_SIZE = 64; + static const size_t CELL_ARRAY_LENGTH = (MINIMUM_CELL_SIZE / sizeof(double)) + (MINIMUM_CELL_SIZE % sizeof(double) != 0 ? sizeof(double) : 0); + public: + // This is still public for now, for use in assertions. + static const size_t CELL_SIZE = CELL_ARRAY_LENGTH * sizeof(double); + private: + static const size_t SMALL_CELL_SIZE = CELL_SIZE / 2; + static const size_t CELL_MASK = CELL_SIZE - 1; + static const size_t CELL_ALIGN_MASK = ~CELL_MASK; + static const size_t BITS_PER_BLOCK = BLOCK_SIZE / CELL_SIZE; + static const size_t CELLS_PER_BLOCK = (BLOCK_SIZE - sizeof(Heap*) - sizeof(WTF::Bitmap<BITS_PER_BLOCK>)) / CELL_SIZE; // Division rounds down intentionally. + + struct CollectorCell { + FixedArray<double, CELL_ARRAY_LENGTH> memory; + }; + + // Cell size needs to be a power of two for CELL_MASK to be valid. + COMPILE_ASSERT(!(sizeof(CollectorCell) % 2), Collector_cell_size_is_power_of_two); + + public: + static MarkedBlock* create(JSGlobalData*); + static void destroy(MarkedBlock*); + + static bool isCellAligned(const void*); + static MarkedBlock* blockFor(const void*); + + Heap* heap() const; + + void* allocate(size_t& nextCell); + void sweep(); + + bool isEmpty(); + + void clearMarks(); + size_t markCount(); + size_t size(); + size_t capacity(); + + size_t cellNumber(const void*); + bool isMarked(const void*); + bool testAndSetMarked(const void*); + void setMarked(const void*); + + template <typename Functor> void forEach(Functor&); + + FixedArray<CollectorCell, CELLS_PER_BLOCK> cells; + + private: + MarkedBlock(const PageAllocationAligned&, JSGlobalData*); + + WTF::Bitmap<BITS_PER_BLOCK> marked; + PageAllocationAligned m_allocation; + Heap* m_heap; + }; + + inline bool MarkedBlock::isCellAligned(const void* p) + { + return !((intptr_t)(p) & CELL_MASK); + } + + inline MarkedBlock* MarkedBlock::blockFor(const void* p) + { + return reinterpret_cast<MarkedBlock*>(reinterpret_cast<uintptr_t>(p) & BLOCK_MASK); + } + + inline Heap* MarkedBlock::heap() const + { + return m_heap; + } + + inline bool MarkedBlock::isEmpty() + { + marked.clear(CELLS_PER_BLOCK - 1); // Clear the always-set last bit to avoid confusing isEmpty(). + bool result = marked.isEmpty(); + marked.set(CELLS_PER_BLOCK - 1); + return result; + } + + inline void MarkedBlock::clearMarks() + { + // allocate() assumes that the last mark bit is always set. + marked.clearAll(); + marked.set(CELLS_PER_BLOCK - 1); + } + + inline size_t MarkedBlock::markCount() + { + return marked.count() - 1; // The last mark bit is always set. + } + + inline size_t MarkedBlock::size() + { + return markCount() * CELL_SIZE; + } + + inline size_t MarkedBlock::capacity() + { + return BLOCK_SIZE; + } + + inline size_t MarkedBlock::cellNumber(const void* cell) + { + return (reinterpret_cast<uintptr_t>(cell) & BLOCK_OFFSET_MASK) / CELL_SIZE; + } + + inline bool MarkedBlock::isMarked(const void* cell) + { + return marked.get(cellNumber(cell)); + } + + inline bool MarkedBlock::testAndSetMarked(const void* cell) + { + return marked.testAndSet(cellNumber(cell)); + } + + inline void MarkedBlock::setMarked(const void* cell) + { + marked.set(cellNumber(cell)); + } + + template <typename Functor> inline void MarkedBlock::forEach(Functor& functor) + { + for (size_t i = 0; i < CELLS_PER_BLOCK - 1; ++i) { // The last cell is a dummy place-holder. + if (!marked.get(i)) + continue; + functor(reinterpret_cast<JSCell*>(&cells[i])); + } + } + +} // namespace JSC + +#endif // MarkedSpace_h |