#ifndef MarkedBlock_h
#define MarkedBlock_h
#include <wtf/Bitmap.h>
#include <wtf/DoublyLinkedList.h>
#include <wtf/HashFunctions.h>
#include <wtf/PageAllocationAligned.h>
#include <wtf/StdLibExtras.h>
#define HEAP_LOG_BLOCK_STATE_TRANSITIONS 0
#if HEAP_LOG_BLOCK_STATE_TRANSITIONS
#define HEAP_DEBUG_BLOCK(block) do { \
printf("%s:%d %s: block %s = %p\n", \
__FILE__, __LINE__, __FUNCTION__, #block, (block)); \
} while (false)
#else
#define HEAP_DEBUG_BLOCK(block) ((void)0)
#endif
namespace JSC {
class Heap;
class JSCell;
typedef uintptr_t Bits;
static const size_t KB = 1024;
class MarkedBlock : public DoublyLinkedListNode<MarkedBlock> {
friend class WTF::DoublyLinkedListNode<MarkedBlock>;
public:
static const size_t atomSize = 4 * sizeof(void*);
static const size_t blockSize = 16 * KB;
static const size_t atomsPerBlock = blockSize / atomSize; static const size_t ownerSetsPerBlock = 8;
struct FreeCell {
FreeCell* next;
void setNoObject()
{
next = 0;
}
};
struct VoidFunctor {
typedef void ReturnType;
void returnValue() { }
};
class OwnerSet {
public:
OwnerSet();
void add(const JSCell*);
void clear();
size_t size();
bool didOverflow();
const JSCell** owners();
private:
static const size_t capacity = 5;
unsigned char m_size;
const JSCell* m_owners[capacity];
};
static MarkedBlock* create(Heap*, size_t cellSize);
static void destroy(MarkedBlock*);
static bool isAtomAligned(const void*);
static MarkedBlock* blockFor(const void*);
static size_t firstAtom();
Heap* heap() const;
bool inNewSpace();
void setInNewSpace(bool);
void* allocate();
void sweep();
FreeCell* lazySweep();
void notifyMayHaveFreshFreeCells();
void initForCellSize(size_t cellSize);
FreeCell* blessNewBlockForFastPath();
void blessNewBlockForSlowPath();
void reset();
void canonicalizeBlock(FreeCell* firstFreeCell);
bool isEmpty();
void clearMarks();
size_t markCount();
size_t cellSize();
size_t size();
size_t capacity();
bool isMarked(const void*);
bool testAndSetMarked(const void*);
bool testAndClearMarked(const void*);
void setMarked(const void*);
void addOldSpaceOwner(const JSCell* owner, const JSCell*);
template <typename Functor> void forEachCell(Functor&);
private:
static const size_t blockMask = ~(blockSize - 1); static const size_t atomMask = ~(atomSize - 1);
enum DestructorState { FreeCellsDontHaveObjects, SomeFreeCellsStillHaveObjects, AllFreeCellsHaveObjects };
typedef char Atom[atomSize];
MarkedBlock(const PageAllocationAligned&, Heap*, size_t cellSize);
Atom* atoms();
size_t atomNumber(const void*);
size_t ownerSetNumber(const JSCell*);
template<DestructorState destructorState>
static void callDestructor(JSCell*, void* jsFinalObjectVPtr);
template<DestructorState destructorState>
void specializedReset();
template<DestructorState destructorState>
void specializedSweep();
template<DestructorState destructorState>
MarkedBlock::FreeCell* produceFreeList();
void setDestructorState(DestructorState destructorState)
{
m_destructorState = static_cast<int8_t>(destructorState);
}
DestructorState destructorState()
{
return static_cast<DestructorState>(m_destructorState);
}
size_t m_endAtom; size_t m_atomsPerCell;
WTF::Bitmap<blockSize / atomSize> m_marks;
bool m_inNewSpace;
int8_t m_destructorState; OwnerSet m_ownerSets[ownerSetsPerBlock];
PageAllocationAligned m_allocation;
Heap* m_heap;
MarkedBlock* m_prev;
MarkedBlock* m_next;
};
inline size_t MarkedBlock::firstAtom()
{
return WTF::roundUpToMultipleOf<atomSize>(sizeof(MarkedBlock)) / atomSize;
}
inline MarkedBlock::Atom* MarkedBlock::atoms()
{
return reinterpret_cast<Atom*>(this);
}
inline bool MarkedBlock::isAtomAligned(const void* p)
{
return !(reinterpret_cast<Bits>(p) & ~atomMask);
}
inline MarkedBlock* MarkedBlock::blockFor(const void* p)
{
return reinterpret_cast<MarkedBlock*>(reinterpret_cast<Bits>(p) & blockMask);
}
inline Heap* MarkedBlock::heap() const
{
return m_heap;
}
inline bool MarkedBlock::inNewSpace()
{
return m_inNewSpace;
}
inline void MarkedBlock::setInNewSpace(bool inNewSpace)
{
m_inNewSpace = inNewSpace;
}
inline void MarkedBlock::notifyMayHaveFreshFreeCells()
{
HEAP_DEBUG_BLOCK(this);
if (destructorState() == FreeCellsDontHaveObjects)
setDestructorState(SomeFreeCellsStillHaveObjects);
}
inline bool MarkedBlock::isEmpty()
{
return m_marks.isEmpty();
}
inline void MarkedBlock::clearMarks()
{
m_marks.clearAll();
}
inline size_t MarkedBlock::markCount()
{
return m_marks.count();
}
inline size_t MarkedBlock::cellSize()
{
return m_atomsPerCell * atomSize;
}
inline size_t MarkedBlock::size()
{
return markCount() * cellSize();
}
inline size_t MarkedBlock::capacity()
{
return m_allocation.size();
}
inline size_t MarkedBlock::atomNumber(const void* p)
{
return (reinterpret_cast<Bits>(p) - reinterpret_cast<Bits>(this)) / atomSize;
}
inline bool MarkedBlock::isMarked(const void* p)
{
return m_marks.get(atomNumber(p));
}
inline bool MarkedBlock::testAndSetMarked(const void* p)
{
return m_marks.testAndSet(atomNumber(p));
}
inline bool MarkedBlock::testAndClearMarked(const void* p)
{
return m_marks.testAndClear(atomNumber(p));
}
inline void MarkedBlock::setMarked(const void* p)
{
m_marks.set(atomNumber(p));
}
template <typename Functor> inline void MarkedBlock::forEachCell(Functor& functor)
{
for (size_t i = firstAtom(); i < m_endAtom; i += m_atomsPerCell) {
if (!m_marks.get(i))
continue;
functor(reinterpret_cast<JSCell*>(&atoms()[i]));
}
}
inline size_t MarkedBlock::ownerSetNumber(const JSCell* cell)
{
return (reinterpret_cast<Bits>(cell) - reinterpret_cast<Bits>(this)) * ownerSetsPerBlock / blockSize;
}
inline void MarkedBlock::addOldSpaceOwner(const JSCell* owner, const JSCell* cell)
{
OwnerSet& ownerSet = m_ownerSets[ownerSetNumber(cell)];
ownerSet.add(owner);
}
inline MarkedBlock::OwnerSet::OwnerSet()
: m_size(0)
{
}
inline void MarkedBlock::OwnerSet::add(const JSCell* owner)
{
if (m_size < capacity) {
m_owners[m_size++] = owner;
return;
}
m_size = capacity + 1; }
inline void MarkedBlock::OwnerSet::clear()
{
m_size = 0;
}
inline size_t MarkedBlock::OwnerSet::size()
{
return m_size;
}
inline bool MarkedBlock::OwnerSet::didOverflow()
{
return m_size > capacity;
}
inline const JSCell** MarkedBlock::OwnerSet::owners()
{
return m_owners;
}
}
namespace WTF {
struct MarkedBlockHash : PtrHash<JSC::MarkedBlock*> {
static unsigned hash(JSC::MarkedBlock* const& key)
{
return reinterpret_cast<JSC::Bits>(key) / JSC::MarkedBlock::blockSize;
}
};
template<> struct DefaultHash<JSC::MarkedBlock*> {
typedef MarkedBlockHash Hash;
};
}
#endif // MarkedBlock_h