--- /dev/null
+/*
+ * Copyright (C) 2011 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef WriteBarrier_h
+#define WriteBarrier_h
+
+#include "HandleTypes.h"
+#include "Heap.h"
+#include "TypeTraits.h"
+
+namespace JSC {
+
+class JSCell;
+class JSGlobalData;
+class JSGlobalObject;
+
+template<class T> class WriteBarrierBase;
+template<> class WriteBarrierBase<JSValue>;
+
+void slowValidateCell(JSCell*);
+void slowValidateCell(JSGlobalObject*);
+
+#if ENABLE(GC_VALIDATION)
+template<class T> inline void validateCell(T cell)
+{
+ ASSERT_GC_OBJECT_INHERITS(cell, &WTF::RemovePointer<T>::Type::s_info);
+}
+
+template<> inline void validateCell<JSCell*>(JSCell* cell)
+{
+ slowValidateCell(cell);
+}
+
+template<> inline void validateCell<JSGlobalObject*>(JSGlobalObject* globalObject)
+{
+ slowValidateCell(globalObject);
+}
+#else
+template<class T> inline void validateCell(T)
+{
+}
+#endif
+
+// We have a separate base class with no constructors for use in Unions.
+template <typename T> class WriteBarrierBase {
+public:
+ void set(JSGlobalData& globalData, const JSCell* owner, T* value)
+ {
+ ASSERT(value);
+ validateCell(value);
+ setEarlyValue(globalData, owner, value);
+ }
+
+ void setMayBeNull(JSGlobalData& globalData, const JSCell* owner, T* value)
+ {
+ if (value)
+ validateCell(value);
+ setEarlyValue(globalData, owner, value);
+ }
+
+ // Should only be used by JSCell during early initialisation
+ // when some basic types aren't yet completely instantiated
+ void setEarlyValue(JSGlobalData&, const JSCell* owner, T* value)
+ {
+ this->m_cell = reinterpret_cast<JSCell*>(value);
+ Heap::writeBarrier(owner, this->m_cell);
+#if ENABLE(JSC_ZOMBIES)
+ ASSERT(!isZombie(owner));
+ ASSERT(!isZombie(m_cell));
+#endif
+ }
+
+ T* get() const
+ {
+ if (m_cell)
+ validateCell(m_cell);
+ return reinterpret_cast<T*>(m_cell);
+ }
+
+ T* operator*() const
+ {
+ ASSERT(m_cell);
+#if ENABLE(JSC_ZOMBIES)
+ ASSERT(!isZombie(m_cell));
+#endif
+ validateCell<T>(static_cast<T*>(m_cell));
+ return static_cast<T*>(m_cell);
+ }
+
+ T* operator->() const
+ {
+ ASSERT(m_cell);
+ validateCell(static_cast<T*>(m_cell));
+ return static_cast<T*>(m_cell);
+ }
+
+ void clear() { m_cell = 0; }
+
+ JSCell** slot() { return &m_cell; }
+
+ typedef T* (WriteBarrierBase::*UnspecifiedBoolType);
+ operator UnspecifiedBoolType*() const { return m_cell ? reinterpret_cast<UnspecifiedBoolType*>(1) : 0; }
+
+ bool operator!() const { return !m_cell; }
+
+ void setWithoutWriteBarrier(T* value)
+ {
+ this->m_cell = reinterpret_cast<JSCell*>(value);
+#if ENABLE(JSC_ZOMBIES)
+ ASSERT(!m_cell || !isZombie(m_cell));
+#endif
+ }
+
+#if ENABLE(GC_VALIDATION)
+ T* unvalidatedGet() const { return reinterpret_cast<T*>(m_cell); }
+#endif
+
+private:
+ JSCell* m_cell;
+};
+
+template <> class WriteBarrierBase<Unknown> {
+public:
+ void set(JSGlobalData&, const JSCell* owner, JSValue value)
+ {
+#if ENABLE(JSC_ZOMBIES)
+ ASSERT(!isZombie(owner));
+ ASSERT(!value.isZombie());
+#endif
+ m_value = JSValue::encode(value);
+ Heap::writeBarrier(owner, value);
+ }
+
+ void setWithoutWriteBarrier(JSValue value)
+ {
+#if ENABLE(JSC_ZOMBIES)
+ ASSERT(!value.isZombie());
+#endif
+ m_value = JSValue::encode(value);
+ }
+
+ JSValue get() const
+ {
+ return JSValue::decode(m_value);
+ }
+ void clear() { m_value = JSValue::encode(JSValue()); }
+ void setUndefined() { m_value = JSValue::encode(jsUndefined()); }
+ bool isNumber() const { return get().isNumber(); }
+ bool isObject() const { return get().isObject(); }
+ bool isNull() const { return get().isNull(); }
+ bool isGetterSetter() const { return get().isGetterSetter(); }
+
+ JSValue* slot()
+ {
+ union {
+ EncodedJSValue* v;
+ JSValue* slot;
+ } u;
+ u.v = &m_value;
+ return u.slot;
+ }
+
+ typedef JSValue (WriteBarrierBase::*UnspecifiedBoolType);
+ operator UnspecifiedBoolType*() const { return get() ? reinterpret_cast<UnspecifiedBoolType*>(1) : 0; }
+ bool operator!() const { return !get(); }
+
+private:
+ EncodedJSValue m_value;
+};
+
+template <typename T> class WriteBarrier : public WriteBarrierBase<T> {
+public:
+ WriteBarrier()
+ {
+ this->setWithoutWriteBarrier(0);
+ }
+
+ WriteBarrier(JSGlobalData& globalData, const JSCell* owner, T* value)
+ {
+ this->set(globalData, owner, value);
+ }
+
+ enum MayBeNullTag { MayBeNull };
+ WriteBarrier(JSGlobalData& globalData, const JSCell* owner, T* value, MayBeNullTag)
+ {
+ this->setMayBeNull(globalData, owner, value);
+ }
+};
+
+template <> class WriteBarrier<Unknown> : public WriteBarrierBase<Unknown> {
+public:
+ WriteBarrier()
+ {
+ this->setWithoutWriteBarrier(JSValue());
+ }
+
+ WriteBarrier(JSGlobalData& globalData, const JSCell* owner, JSValue value)
+ {
+ this->set(globalData, owner, value);
+ }
+};
+
+template <typename U, typename V> inline bool operator==(const WriteBarrierBase<U>& lhs, const WriteBarrierBase<V>& rhs)
+{
+ return lhs.get() == rhs.get();
+}
+
+// MarkStack functions
+
+template<typename T> inline void MarkStack::append(WriteBarrierBase<T>* slot)
+{
+ internalAppend(*slot->slot());
+}
+
+inline void MarkStack::appendValues(WriteBarrierBase<Unknown>* barriers, size_t count, MarkSetProperties properties)
+{
+ JSValue* values = barriers->slot();
+#if ENABLE(GC_VALIDATION)
+ validateSet(values, count);
+#endif
+ if (count)
+ m_markSets.append(MarkSet(values, values + count, properties));
+}
+
+} // namespace JSC
+
+#endif // WriteBarrier_h
projects / apple / javascriptcore.git / blobdiff