#ifndef Collector_h
#define Collector_h
#include <stddef.h>
#include <string.h>
#include <wtf/HashCountedSet.h>
#include <wtf/HashSet.h>
#include <wtf/Noncopyable.h>
#include <wtf/OwnPtr.h>
#include <wtf/Threading.h>
#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 MarkedArgumentBuffer;
class CollectorBlock;
class JSCell;
class JSGlobalData;
class JSValue;
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
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();
static const size_t minExtraCostSize = 256;
void reportExtraMemoryCost(size_t cost);
size_t objectCount();
struct Statistics {
size_t size;
size_t free;
};
Statistics statistics() const;
void setGCProtectNeedsLocking();
void protect(JSValue);
void unprotect(JSValue);
static Heap* heap(JSValue);
size_t globalObjectCount();
size_t protectedObjectCount();
size_t protectedGlobalObjectCount();
HashCountedSet<const char*>* protectedObjectTypeCounts();
void registerThread();
static bool isCellMarked(const JSCell*);
static void markCell(JSCell*);
void markConservatively(void* start, void* end);
HashSet<MarkedArgumentBuffer*>& markListSet() { if (!m_markListSet) m_markListSet = new HashSet<MarkedArgumentBuffer*>; return *m_markListSet; }
JSGlobalData* globalData() const { return m_globalData; }
static bool isNumber(JSCell*);
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; ProtectCountSet m_protectedValues;
HashSet<MarkedArgumentBuffer*>* m_markListSet;
#if ENABLE(JSC_MULTIPLE_THREADS)
void makeUsableFromMultipleThreads();
static void unregisterThread(void*);
void unregisterThread();
Mutex m_registeredThreadsMutex;
Thread* m_registeredThreads;
pthread_key_t m_currentThreadRegistrar;
#endif
JSGlobalData* m_globalData;
};
template<size_t bytesPerWord> struct CellSize;
#if USE(JSVALUE32)
template<> struct CellSize<sizeof(uint32_t)> { static const size_t m_value = 32; };
#else
template<> struct CellSize<sizeof(uint32_t)> { static const size_t m_value = 64; };
#endif
template<> struct CellSize<sizeof(uint64_t)> { static const size_t m_value = 64; };
const size_t BLOCK_SIZE = 16 * 4096;
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));
}
}
#endif