#ifndef JITWriteBarrier_h
#define JITWriteBarrier_h
#if ENABLE(JIT)
#include "MacroAssembler.h"
#include "MarkStack.h"
#include "WriteBarrier.h"
namespace JSC {
class JSCell;
class JSGlobalData;
#define JITWriteBarrierFlag ((void*)2)
class JITWriteBarrierBase {
public:
typedef void* (JITWriteBarrierBase::*UnspecifiedBoolType);
operator UnspecifiedBoolType*() const { return get() ? reinterpret_cast<UnspecifiedBoolType*>(1) : 0; }
bool operator!() const { return !get(); }
void setFlagOnBarrier()
{
ASSERT(!m_location);
m_location = CodeLocationDataLabelPtr(JITWriteBarrierFlag);
}
bool isFlagged() const
{
return !!m_location;
}
void setLocation(CodeLocationDataLabelPtr location)
{
ASSERT(!m_location);
m_location = location;
}
CodeLocationDataLabelPtr location() const
{
ASSERT((!!m_location) && m_location.executableAddress() != JITWriteBarrierFlag);
return m_location;
}
void clear() { clear(0); }
void clearToMaxUnsigned() { clear(reinterpret_cast<void*>(-1)); }
protected:
JITWriteBarrierBase()
{
}
void set(JSGlobalData&, CodeLocationDataLabelPtr location, JSCell* owner, JSCell* value)
{
Heap::writeBarrier(owner, value);
m_location = location;
ASSERT(((!!m_location) && m_location.executableAddress() != JITWriteBarrierFlag) || (location.executableAddress() == m_location.executableAddress()));
MacroAssembler::repatchPointer(m_location, value);
ASSERT(get() == value);
}
JSCell* get() const
{
if (!m_location || m_location.executableAddress() == JITWriteBarrierFlag)
return 0;
void* result = static_cast<JSCell*>(MacroAssembler::readPointer(m_location));
if (result == (void*)-1)
return 0;
return static_cast<JSCell*>(result);
}
private:
void clear(void* clearedValue)
{
if (!m_location)
return;
if (m_location.executableAddress() != JITWriteBarrierFlag)
MacroAssembler::repatchPointer(m_location, clearedValue);
}
CodeLocationDataLabelPtr m_location;
};
#undef JITWriteBarrierFlag
template <typename T> class JITWriteBarrier : public JITWriteBarrierBase {
public:
JITWriteBarrier()
{
}
void set(JSGlobalData& globalData, CodeLocationDataLabelPtr location, JSCell* owner, T* value)
{
validateCell(owner);
validateCell(value);
JITWriteBarrierBase::set(globalData, location, owner, value);
}
void set(JSGlobalData& globalData, JSCell* owner, T* value)
{
set(globalData, location(), owner, value);
}
T* get() const
{
T* result = static_cast<T*>(JITWriteBarrierBase::get());
if (result)
validateCell(result);
return result;
}
};
template<typename T> inline void MarkStack::append(JITWriteBarrier<T>* slot)
{
internalAppend(slot->get());
}
}
#endif // ENABLE(JIT)
#endif