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/*
* Copyright (C) 2015 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 "DirectArguments.h"
#include "CodeBlock.h"
#include "CopiedBlockInlines.h"
#include "CopyVisitorInlines.h"
#include "GenericArgumentsInlines.h"
#include "JSCInlines.h"
namespace JSC {
STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(DirectArguments);
const ClassInfo DirectArguments::s_info = { "Arguments", &Base::s_info, 0, CREATE_METHOD_TABLE(DirectArguments) };
DirectArguments::DirectArguments(VM& vm, Structure* structure, unsigned length, unsigned capacity)
: GenericArguments(vm, structure)
, m_length(length)
, m_minCapacity(capacity)
{
// When we construct the object from C++ code, we expect the capacity to be at least as large as
// length. JIT-allocated DirectArguments objects play evil tricks, though.
ASSERT(capacity >= length);
}
DirectArguments* DirectArguments::createUninitialized(
VM& vm, Structure* structure, unsigned length, unsigned capacity)
{
DirectArguments* result =
new (NotNull, allocateCell<DirectArguments>(vm.heap, allocationSize(capacity)))
DirectArguments(vm, structure, length, capacity);
result->finishCreation(vm);
return result;
}
DirectArguments* DirectArguments::create(VM& vm, Structure* structure, unsigned length, unsigned capacity)
{
DirectArguments* result = createUninitialized(vm, structure, length, capacity);
for (unsigned i = capacity; i--;)
result->storage()[i].clear();
return result;
}
DirectArguments* DirectArguments::createByCopying(ExecState* exec)
{
VM& vm = exec->vm();
unsigned length = exec->argumentCount();
unsigned capacity = std::max(length, static_cast<unsigned>(exec->codeBlock()->numParameters() - 1));
DirectArguments* result = createUninitialized(
vm, exec->lexicalGlobalObject()->directArgumentsStructure(), length, capacity);
for (unsigned i = capacity; i--;)
result->storage()[i].set(vm, result, exec->getArgumentUnsafe(i));
result->callee().set(vm, result, jsCast<JSFunction*>(exec->callee()));
return result;
}
size_t DirectArguments::estimatedSize(JSCell* cell)
{
DirectArguments* thisObject = jsCast<DirectArguments*>(cell);
size_t overridesSize = thisObject->m_overrides ? thisObject->overridesSize() : 0;
return Base::estimatedSize(cell) + overridesSize;
}
void DirectArguments::visitChildren(JSCell* thisCell, SlotVisitor& visitor)
{
DirectArguments* thisObject = static_cast<DirectArguments*>(thisCell);
ASSERT_GC_OBJECT_INHERITS(thisObject, info());
Base::visitChildren(thisObject, visitor);
visitor.appendValues(thisObject->storage(), std::max(thisObject->m_length, thisObject->m_minCapacity));
visitor.append(&thisObject->m_callee);
if (thisObject->m_overrides) {
visitor.copyLater(
thisObject, DirectArgumentsOverridesCopyToken,
thisObject->m_overrides.getWithoutBarrier(), thisObject->overridesSize());
}
}
void DirectArguments::copyBackingStore(JSCell* thisCell, CopyVisitor& visitor, CopyToken token)
{
DirectArguments* thisObject = static_cast<DirectArguments*>(thisCell);
ASSERT_GC_OBJECT_INHERITS(thisObject, info());
RELEASE_ASSERT(token == DirectArgumentsOverridesCopyToken);
void* oldOverrides = thisObject->m_overrides.getWithoutBarrier();
if (visitor.checkIfShouldCopy(oldOverrides)) {
bool* newOverrides = static_cast<bool*>(visitor.allocateNewSpace(thisObject->overridesSize()));
memcpy(newOverrides, oldOverrides, thisObject->m_length);
thisObject->m_overrides.setWithoutBarrier(newOverrides);
visitor.didCopy(oldOverrides, thisObject->overridesSize());
}
}
Structure* DirectArguments::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
{
return Structure::create(vm, globalObject, prototype, TypeInfo(DirectArgumentsType, StructureFlags), info());
}
void DirectArguments::overrideThings(VM& vm)
{
RELEASE_ASSERT(!m_overrides);
putDirect(vm, vm.propertyNames->length, jsNumber(m_length), DontEnum);
putDirect(vm, vm.propertyNames->callee, m_callee.get(), DontEnum);
putDirect(vm, vm.propertyNames->iteratorSymbol, globalObject()->arrayProtoValuesFunction(), DontEnum);
void* backingStore;
RELEASE_ASSERT(vm.heap.tryAllocateStorage(this, overridesSize(), &backingStore));
bool* overrides = static_cast<bool*>(backingStore);
m_overrides.set(vm, this, overrides);
for (unsigned i = m_length; i--;)
overrides[i] = false;
}
void DirectArguments::overrideThingsIfNecessary(VM& vm)
{
if (!m_overrides)
overrideThings(vm);
}
void DirectArguments::overrideArgument(VM& vm, unsigned index)
{
overrideThingsIfNecessary(vm);
m_overrides.get(this)[index] = true;
}
void DirectArguments::copyToArguments(ExecState* exec, VirtualRegister firstElementDest, unsigned offset, unsigned length)
{
if (!m_overrides) {
unsigned limit = std::min(length + offset, m_length);
unsigned i;
VirtualRegister start = firstElementDest - offset;
for (i = offset; i < limit; ++i)
exec->r(start + i) = storage()[i].get();
for (; i < length; ++i)
exec->r(start + i) = get(exec, i);
return;
}
GenericArguments::copyToArguments(exec, firstElementDest, offset, length);
}
unsigned DirectArguments::overridesSize()
{
// We always allocate something; in the relatively uncommon case of overriding an empty argument we
// still allocate so that m_overrides is non-null. We use that to indicate that the other properties
// (length, etc) are overridden.
return WTF::roundUpToMultipleOf<8>(m_length ? m_length : 1);
}
} // namespace JSC
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