DirectArguments.cpp [plain text]
#include "config.h"
#include "DirectArguments.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)
{
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;
}
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.get(), 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);
bool* oldOverrides = thisObject->m_overrides.get();
if (!oldOverrides)
return;
if (visitor.checkIfShouldCopy(oldOverrides)) {
bool* newOverrides = static_cast<bool*>(visitor.allocateNewSpace(thisObject->overridesSize()));
memcpy(newOverrides, oldOverrides, thisObject->m_length);
thisObject->m_overrides.setWithoutWriteBarrier(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));
m_overrides.set(vm, this, static_cast<bool*>(backingStore));
for (unsigned i = m_length; i--;)
m_overrides.get()[i] = false;
}
void DirectArguments::overrideThingsIfNecessary(VM& vm)
{
if (!m_overrides)
overrideThings(vm);
}
void DirectArguments::overrideArgument(VM& vm, unsigned index)
{
overrideThingsIfNecessary(vm);
m_overrides.get()[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()
{
return WTF::roundUpToMultipleOf<8>(m_length ? m_length : 1);
}
}