Source/JavaScriptCore/runtime/ClonedArguments.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2015-2017 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. ``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
  * 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.
  */

 #include "config.h"
 #include "ClonedArguments.h"

 #include "GetterSetter.h"
 #include "InlineCallFrame.h"
 #include "JSCInlines.h"

 namespace JSC {

 STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(ClonedArguments);

 const ClassInfo ClonedArguments::s_info = { "Arguments", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(ClonedArguments) };

 ClonedArguments::ClonedArguments(VM& vm, Structure* structure, Butterfly* butterfly)
     : Base(vm, structure, butterfly)
 {
 }

 ClonedArguments* ClonedArguments::createEmpty(
     VM& vm, Structure* structure, JSFunction* callee, unsigned length)
 {
     unsigned vectorLength = length;
     if (vectorLength > MAX_STORAGE_VECTOR_LENGTH)
         return 0;

     Butterfly* butterfly;
     if (UNLIKELY(structure->mayInterceptIndexedAccesses() || structure->storedPrototypeObject()->needsSlowPutIndexing(vm))) {
         butterfly = createArrayStorageButterfly(vm, nullptr, structure, length, vectorLength);
         butterfly->arrayStorage()->m_numValuesInVector = vectorLength;
     } else {
         IndexingHeader indexingHeader;
         indexingHeader.setVectorLength(vectorLength);
         indexingHeader.setPublicLength(length);
         butterfly = Butterfly::tryCreate(vm, 0, 0, structure->outOfLineCapacity(), true, indexingHeader, vectorLength * sizeof(EncodedJSValue));
         if (!butterfly)
             return 0;

         for (unsigned i = length; i < vectorLength; ++i)
             butterfly->contiguous().atUnsafe(i).clear();
     }

     ClonedArguments* result =
         new (NotNull, allocateCell<ClonedArguments>(vm.heap))
         ClonedArguments(vm, structure, butterfly);
     result->finishCreation(vm);

     result->m_callee.set(vm, result, callee);
     result->putDirect(vm, clonedArgumentsLengthPropertyOffset, jsNumber(length));
     return result;
 }

 ClonedArguments* ClonedArguments::createEmpty(JSGlobalObject* globalObject, JSFunction* callee, unsigned length)
 {
     VM& vm = globalObject->vm();
     // NB. Some clients might expect that the global object of of this object is the global object
     // of the callee. We don't do this for now, but maybe we should.
     ClonedArguments* result = createEmpty(vm, globalObject->clonedArgumentsStructure(), callee, length);
     ASSERT(!result->needsSlowPutIndexing(vm) || shouldUseSlowPut(result->structure(vm)->indexingType()));
     return result;
 }

 ClonedArguments* ClonedArguments::createWithInlineFrame(JSGlobalObject* globalObject, CallFrame* targetFrame, InlineCallFrame* inlineCallFrame, ArgumentsMode mode)
 {
     JSFunction* callee;

     if (inlineCallFrame)
         callee = jsCast<JSFunction*>(inlineCallFrame->calleeRecovery.recover(targetFrame));
     else
         callee = jsCast<JSFunction*>(targetFrame->jsCallee());

     ClonedArguments* result = nullptr;

     unsigned length = 0; // Initialize because VC needs it.
     switch (mode) {
     case ArgumentsMode::Cloned: {
         if (inlineCallFrame) {
             if (inlineCallFrame->argumentCountRegister.isValid())
                 length = targetFrame->r(inlineCallFrame->argumentCountRegister).unboxedInt32();
             else
                 length = inlineCallFrame->argumentCountIncludingThis;
             length--;
             result = createEmpty(globalObject, callee, length);

             for (unsigned i = length; i--;)
                 result->putDirectIndex(globalObject, i, inlineCallFrame->argumentsWithFixup[i + 1].recover(targetFrame));
         } else {
             length = targetFrame->argumentCount();
             result = createEmpty(globalObject, callee, length);

             for (unsigned i = length; i--;)
                 result->putDirectIndex(globalObject, i, targetFrame->uncheckedArgument(i));
         }
         break;
     }

     case ArgumentsMode::FakeValues: {
         result = createEmpty(globalObject, callee, 0);
         break;
     } }

     ASSERT(globalObject->clonedArgumentsStructure() == result->structure(globalObject->vm()));
     ASSERT(!result->needsSlowPutIndexing(globalObject->vm()) || shouldUseSlowPut(result->structure(globalObject->vm())->indexingType()));
     return result;
 }

 ClonedArguments* ClonedArguments::createWithMachineFrame(JSGlobalObject* globalObject, CallFrame* targetFrame, ArgumentsMode mode)
 {
     ClonedArguments* result = createWithInlineFrame(globalObject, targetFrame, nullptr, mode);
     ASSERT(!result->needsSlowPutIndexing(globalObject->vm()) || shouldUseSlowPut(result->structure(globalObject->vm())->indexingType()));
     return result;
 }

 ClonedArguments* ClonedArguments::createByCopyingFrom(
     JSGlobalObject* globalObject, Structure* structure, Register* argumentStart, unsigned length,
     JSFunction* callee)
 {
     VM& vm = globalObject->vm();
     ClonedArguments* result = createEmpty(vm, structure, callee, length);

     for (unsigned i = length; i--;)
         result->putDirectIndex(globalObject, i, argumentStart[i].jsValue());
     ASSERT(!result->needsSlowPutIndexing(vm) || shouldUseSlowPut(result->structure(vm)->indexingType()));
     return result;
 }

 Structure* ClonedArguments::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype, IndexingType indexingType)
 {
     Structure* structure = Structure::create(vm, globalObject, prototype, TypeInfo(ClonedArgumentsType, StructureFlags), info(), indexingType);
     structure->addPropertyWithoutTransition(
         vm, vm.propertyNames->length, static_cast<unsigned>(PropertyAttribute::DontEnum),
         [&] (const GCSafeConcurrentJSLocker&, PropertyOffset offset, PropertyOffset newLastOffset) {
             RELEASE_ASSERT(offset == clonedArgumentsLengthPropertyOffset);
             structure->setLastOffset(newLastOffset);
         });
     return structure;
 }

 Structure* ClonedArguments::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
 {
     // We use contiguous storage because optimizations in the FTL assume that cloned arguments creation always produces the same initial structure.
     return createStructure(vm, globalObject, prototype, NonArrayWithContiguous);
 }

 Structure* ClonedArguments::createSlowPutStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
 {
     return createStructure(vm, globalObject, prototype, NonArrayWithSlowPutArrayStorage);
 }

 bool ClonedArguments::getOwnPropertySlot(JSObject* object, JSGlobalObject* globalObject, PropertyName ident, PropertySlot& slot)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
     VM& vm = globalObject->vm();

     if (!thisObject->specialsMaterialized()) {
         FunctionExecutable* executable = jsCast<FunctionExecutable*>(thisObject->m_callee->executable());
         bool isStrictMode = executable->isStrictMode();

         if (ident == vm.propertyNames->callee) {
             if (isStrictMode) {
                 slot.setGetterSlot(thisObject, PropertyAttribute::DontDelete | PropertyAttribute::DontEnum | PropertyAttribute::Accessor, thisObject->globalObject(vm)->throwTypeErrorArgumentsCalleeAndCallerGetterSetter());
                 return true;
             }
             slot.setValue(thisObject, 0, thisObject->m_callee.get());
             return true;
         }

         if (ident == vm.propertyNames->iteratorSymbol) {
             slot.setValue(thisObject, static_cast<unsigned>(PropertyAttribute::DontEnum), thisObject->globalObject(vm)->arrayProtoValuesFunction());
             return true;
         }
     }

     return Base::getOwnPropertySlot(thisObject, globalObject, ident, slot);
 }

 void ClonedArguments::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, EnumerationMode mode)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
     thisObject->materializeSpecialsIfNecessary(globalObject);
     Base::getOwnPropertyNames(thisObject, globalObject, array, mode);
 }

 bool ClonedArguments::put(JSCell* cell, JSGlobalObject* globalObject, PropertyName ident, JSValue value, PutPropertySlot& slot)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
     VM& vm = globalObject->vm();

     if (ident == vm.propertyNames->callee
         || ident == vm.propertyNames->iteratorSymbol) {
         thisObject->materializeSpecialsIfNecessary(globalObject);
         PutPropertySlot dummy = slot; // Shadow the given PutPropertySlot to prevent caching.
         return Base::put(thisObject, globalObject, ident, value, dummy);
     }

     return Base::put(thisObject, globalObject, ident, value, slot);
 }

 bool ClonedArguments::deleteProperty(JSCell* cell, JSGlobalObject* globalObject, PropertyName ident)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
     VM& vm = globalObject->vm();

     if (ident == vm.propertyNames->callee
         || ident == vm.propertyNames->iteratorSymbol)
         thisObject->materializeSpecialsIfNecessary(globalObject);

     return Base::deleteProperty(thisObject, globalObject, ident);
 }

 bool ClonedArguments::defineOwnProperty(JSObject* object, JSGlobalObject* globalObject, PropertyName ident, const PropertyDescriptor& descriptor, bool shouldThrow)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
     VM& vm = globalObject->vm();

     if (ident == vm.propertyNames->callee
         || ident == vm.propertyNames->iteratorSymbol)
         thisObject->materializeSpecialsIfNecessary(globalObject);

     return Base::defineOwnProperty(object, globalObject, ident, descriptor, shouldThrow);
 }

 void ClonedArguments::materializeSpecials(JSGlobalObject* globalObject)
 {
     RELEASE_ASSERT(!specialsMaterialized());
     VM& vm = globalObject->vm();

     FunctionExecutable* executable = jsCast<FunctionExecutable*>(m_callee->executable());
     bool isStrictMode = executable->isStrictMode();

     if (isStrictMode)
         putDirectAccessor(globalObject, vm.propertyNames->callee, this->globalObject(vm)->throwTypeErrorArgumentsCalleeAndCallerGetterSetter(), PropertyAttribute::DontDelete | PropertyAttribute::DontEnum | PropertyAttribute::Accessor);
     else
         putDirect(vm, vm.propertyNames->callee, JSValue(m_callee.get()));

     putDirect(vm, vm.propertyNames->iteratorSymbol, this->globalObject(vm)->arrayProtoValuesFunction(), static_cast<unsigned>(PropertyAttribute::DontEnum));

     m_callee.clear();
 }

 void ClonedArguments::materializeSpecialsIfNecessary(JSGlobalObject* globalObject)
 {
     if (!specialsMaterialized())
         materializeSpecials(globalObject);
 }

 void ClonedArguments::visitChildren(JSCell* cell, SlotVisitor& visitor)
 {
     ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
     ASSERT_GC_OBJECT_INHERITS(thisObject, info());
     Base::visitChildren(thisObject, visitor);
     visitor.append(thisObject->m_callee);
 }

 } // namespace JSC
	/*
	* Copyright (C) 2015-2017 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. ``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
	* 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.
	*/

	#include "config.h"
	#include "ClonedArguments.h"

	#include "GetterSetter.h"
	#include "InlineCallFrame.h"
	#include "JSCInlines.h"

	namespace JSC {

	STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(ClonedArguments);

	const ClassInfo ClonedArguments::s_info = { "Arguments", &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(ClonedArguments) };

	ClonedArguments::ClonedArguments(VM& vm, Structure* structure, Butterfly* butterfly)
	: Base(vm, structure, butterfly)
	{
	}

	ClonedArguments* ClonedArguments::createEmpty(
	VM& vm, Structure* structure, JSFunction* callee, unsigned length)
	{
	unsigned vectorLength = length;
	if (vectorLength > MAX_STORAGE_VECTOR_LENGTH)
	return 0;

	Butterfly* butterfly;
	if (UNLIKELY(structure->mayInterceptIndexedAccesses() \|\| structure->storedPrototypeObject()->needsSlowPutIndexing(vm))) {
	butterfly = createArrayStorageButterfly(vm, nullptr, structure, length, vectorLength);
	butterfly->arrayStorage()->m_numValuesInVector = vectorLength;
	} else {
	IndexingHeader indexingHeader;
	indexingHeader.setVectorLength(vectorLength);
	indexingHeader.setPublicLength(length);
	butterfly = Butterfly::tryCreate(vm, 0, 0, structure->outOfLineCapacity(), true, indexingHeader, vectorLength * sizeof(EncodedJSValue));
	if (!butterfly)
	return 0;

	for (unsigned i = length; i < vectorLength; ++i)
	butterfly->contiguous().atUnsafe(i).clear();
	}

	ClonedArguments* result =
	new (NotNull, allocateCell<ClonedArguments>(vm.heap))
	ClonedArguments(vm, structure, butterfly);
	result->finishCreation(vm);

	result->m_callee.set(vm, result, callee);
	result->putDirect(vm, clonedArgumentsLengthPropertyOffset, jsNumber(length));
	return result;
	}

	ClonedArguments* ClonedArguments::createEmpty(JSGlobalObject* globalObject, JSFunction* callee, unsigned length)
	{
	VM& vm = globalObject->vm();
	// NB. Some clients might expect that the global object of of this object is the global object
	// of the callee. We don't do this for now, but maybe we should.
	ClonedArguments* result = createEmpty(vm, globalObject->clonedArgumentsStructure(), callee, length);
	ASSERT(!result->needsSlowPutIndexing(vm) \|\| shouldUseSlowPut(result->structure(vm)->indexingType()));
	return result;
	}

	ClonedArguments* ClonedArguments::createWithInlineFrame(JSGlobalObject* globalObject, CallFrame* targetFrame, InlineCallFrame* inlineCallFrame, ArgumentsMode mode)
	{
	JSFunction* callee;

	if (inlineCallFrame)
	callee = jsCast<JSFunction*>(inlineCallFrame->calleeRecovery.recover(targetFrame));
	else
	callee = jsCast<JSFunction*>(targetFrame->jsCallee());

	ClonedArguments* result = nullptr;

	unsigned length = 0; // Initialize because VC needs it.
	switch (mode) {
	case ArgumentsMode::Cloned: {
	if (inlineCallFrame) {
	if (inlineCallFrame->argumentCountRegister.isValid())
	length = targetFrame->r(inlineCallFrame->argumentCountRegister).unboxedInt32();
	else
	length = inlineCallFrame->argumentCountIncludingThis;
	length--;
	result = createEmpty(globalObject, callee, length);

	for (unsigned i = length; i--;)
	result->putDirectIndex(globalObject, i, inlineCallFrame->argumentsWithFixup[i + 1].recover(targetFrame));
	} else {
	length = targetFrame->argumentCount();
	result = createEmpty(globalObject, callee, length);

	for (unsigned i = length; i--;)
	result->putDirectIndex(globalObject, i, targetFrame->uncheckedArgument(i));
	}
	break;
	}

	case ArgumentsMode::FakeValues: {
	result = createEmpty(globalObject, callee, 0);
	break;
	} }

	ASSERT(globalObject->clonedArgumentsStructure() == result->structure(globalObject->vm()));
	ASSERT(!result->needsSlowPutIndexing(globalObject->vm()) \|\| shouldUseSlowPut(result->structure(globalObject->vm())->indexingType()));
	return result;
	}

	ClonedArguments* ClonedArguments::createWithMachineFrame(JSGlobalObject* globalObject, CallFrame* targetFrame, ArgumentsMode mode)
	{
	ClonedArguments* result = createWithInlineFrame(globalObject, targetFrame, nullptr, mode);
	ASSERT(!result->needsSlowPutIndexing(globalObject->vm()) \|\| shouldUseSlowPut(result->structure(globalObject->vm())->indexingType()));
	return result;
	}

	ClonedArguments* ClonedArguments::createByCopyingFrom(
	JSGlobalObject* globalObject, Structure* structure, Register* argumentStart, unsigned length,
	JSFunction* callee)
	{
	VM& vm = globalObject->vm();
	ClonedArguments* result = createEmpty(vm, structure, callee, length);

	for (unsigned i = length; i--;)
	result->putDirectIndex(globalObject, i, argumentStart[i].jsValue());
	ASSERT(!result->needsSlowPutIndexing(vm) \|\| shouldUseSlowPut(result->structure(vm)->indexingType()));
	return result;
	}

	Structure* ClonedArguments::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype, IndexingType indexingType)
	{
	Structure* structure = Structure::create(vm, globalObject, prototype, TypeInfo(ClonedArgumentsType, StructureFlags), info(), indexingType);
	structure->addPropertyWithoutTransition(
	vm, vm.propertyNames->length, static_cast<unsigned>(PropertyAttribute::DontEnum),
	[&] (const GCSafeConcurrentJSLocker&, PropertyOffset offset, PropertyOffset newLastOffset) {
	RELEASE_ASSERT(offset == clonedArgumentsLengthPropertyOffset);
	structure->setLastOffset(newLastOffset);
	});
	return structure;
	}

	Structure* ClonedArguments::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
	{
	// We use contiguous storage because optimizations in the FTL assume that cloned arguments creation always produces the same initial structure.
	return createStructure(vm, globalObject, prototype, NonArrayWithContiguous);
	}

	Structure* ClonedArguments::createSlowPutStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
	{
	return createStructure(vm, globalObject, prototype, NonArrayWithSlowPutArrayStorage);
	}

	bool ClonedArguments::getOwnPropertySlot(JSObject* object, JSGlobalObject* globalObject, PropertyName ident, PropertySlot& slot)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
	VM& vm = globalObject->vm();

	if (!thisObject->specialsMaterialized()) {
	FunctionExecutable* executable = jsCast<FunctionExecutable*>(thisObject->m_callee->executable());
	bool isStrictMode = executable->isStrictMode();

	if (ident == vm.propertyNames->callee) {
	if (isStrictMode) {
	slot.setGetterSlot(thisObject, PropertyAttribute::DontDelete \| PropertyAttribute::DontEnum \| PropertyAttribute::Accessor, thisObject->globalObject(vm)->throwTypeErrorArgumentsCalleeAndCallerGetterSetter());
	return true;
	}
	slot.setValue(thisObject, 0, thisObject->m_callee.get());
	return true;
	}

	if (ident == vm.propertyNames->iteratorSymbol) {
	slot.setValue(thisObject, static_cast<unsigned>(PropertyAttribute::DontEnum), thisObject->globalObject(vm)->arrayProtoValuesFunction());
	return true;
	}
	}

	return Base::getOwnPropertySlot(thisObject, globalObject, ident, slot);
	}

	void ClonedArguments::getOwnPropertyNames(JSObject* object, JSGlobalObject* globalObject, PropertyNameArray& array, EnumerationMode mode)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
	thisObject->materializeSpecialsIfNecessary(globalObject);
	Base::getOwnPropertyNames(thisObject, globalObject, array, mode);
	}

	bool ClonedArguments::put(JSCell* cell, JSGlobalObject* globalObject, PropertyName ident, JSValue value, PutPropertySlot& slot)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
	VM& vm = globalObject->vm();

	if (ident == vm.propertyNames->callee
	\|\| ident == vm.propertyNames->iteratorSymbol) {
	thisObject->materializeSpecialsIfNecessary(globalObject);
	PutPropertySlot dummy = slot; // Shadow the given PutPropertySlot to prevent caching.
	return Base::put(thisObject, globalObject, ident, value, dummy);
	}

	return Base::put(thisObject, globalObject, ident, value, slot);
	}

	bool ClonedArguments::deleteProperty(JSCell* cell, JSGlobalObject* globalObject, PropertyName ident)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
	VM& vm = globalObject->vm();

	if (ident == vm.propertyNames->callee
	\|\| ident == vm.propertyNames->iteratorSymbol)
	thisObject->materializeSpecialsIfNecessary(globalObject);

	return Base::deleteProperty(thisObject, globalObject, ident);
	}

	bool ClonedArguments::defineOwnProperty(JSObject* object, JSGlobalObject* globalObject, PropertyName ident, const PropertyDescriptor& descriptor, bool shouldThrow)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(object);
	VM& vm = globalObject->vm();

	if (ident == vm.propertyNames->callee
	\|\| ident == vm.propertyNames->iteratorSymbol)
	thisObject->materializeSpecialsIfNecessary(globalObject);

	return Base::defineOwnProperty(object, globalObject, ident, descriptor, shouldThrow);
	}

	void ClonedArguments::materializeSpecials(JSGlobalObject* globalObject)
	{
	RELEASE_ASSERT(!specialsMaterialized());
	VM& vm = globalObject->vm();

	FunctionExecutable* executable = jsCast<FunctionExecutable*>(m_callee->executable());
	bool isStrictMode = executable->isStrictMode();

	if (isStrictMode)
	putDirectAccessor(globalObject, vm.propertyNames->callee, this->globalObject(vm)->throwTypeErrorArgumentsCalleeAndCallerGetterSetter(), PropertyAttribute::DontDelete \| PropertyAttribute::DontEnum \| PropertyAttribute::Accessor);
	else
	putDirect(vm, vm.propertyNames->callee, JSValue(m_callee.get()));

	putDirect(vm, vm.propertyNames->iteratorSymbol, this->globalObject(vm)->arrayProtoValuesFunction(), static_cast<unsigned>(PropertyAttribute::DontEnum));

	m_callee.clear();
	}

	void ClonedArguments::materializeSpecialsIfNecessary(JSGlobalObject* globalObject)
	{
	if (!specialsMaterialized())
	materializeSpecials(globalObject);
	}

	void ClonedArguments::visitChildren(JSCell* cell, SlotVisitor& visitor)
	{
	ClonedArguments* thisObject = jsCast<ClonedArguments*>(cell);
	ASSERT_GC_OBJECT_INHERITS(thisObject, info());
	Base::visitChildren(thisObject, visitor);
	visitor.append(thisObject->m_callee);
	}

	} // namespace JSC