#pragma once
#include "GenericArguments.h"
#include "JSLexicalEnvironment.h"
namespace JSC {
class ScopedArguments final : public GenericArguments<ScopedArguments> {
private:
ScopedArguments(VM&, Structure*, WriteBarrier<Unknown>* storage);
void finishCreation(VM&, JSFunction* callee, ScopedArgumentsTable*, JSLexicalEnvironment*);
using Base = GenericArguments<ScopedArguments>;
public:
template<typename CellType>
static CompleteSubspace* subspaceFor(VM& vm)
{
RELEASE_ASSERT(!CellType::needsDestruction);
return &vm.jsValueGigacageCellSpace;
}
static ScopedArguments* createUninitialized(VM&, Structure*, JSFunction* callee, ScopedArgumentsTable*, JSLexicalEnvironment*, unsigned totalLength);
static ScopedArguments* create(VM&, Structure*, JSFunction* callee, ScopedArgumentsTable*, JSLexicalEnvironment*, unsigned totalLength);
static ScopedArguments* createByCopying(ExecState*, ScopedArgumentsTable*, JSLexicalEnvironment*);
static ScopedArguments* createByCopyingFrom(VM&, Structure*, Register* argumentsStart, unsigned totalLength, JSFunction* callee, ScopedArgumentsTable*, JSLexicalEnvironment*);
static void visitChildren(JSCell*, SlotVisitor&);
uint32_t internalLength() const
{
return storageHeader().totalLength;
}
uint32_t length(ExecState* exec) const
{
VM& vm = exec->vm();
if (UNLIKELY(storageHeader().overrodeThings))
return get(exec, vm.propertyNames->length).toUInt32(exec);
return internalLength();
}
bool isMappedArgument(uint32_t i) const
{
WriteBarrier<Unknown>* storage = overflowStorage();
if (i >= storageHeader(storage).totalLength)
return false;
unsigned namedLength = m_table->length();
if (i < namedLength)
return !!m_table->get(i);
return !!storage[i - namedLength].get();
}
bool isMappedArgumentInDFG(uint32_t i) const
{
return isMappedArgument(i);
}
JSValue getIndexQuickly(uint32_t i) const
{
ASSERT_WITH_SECURITY_IMPLICATION(isMappedArgument(i));
WriteBarrier<Unknown>* storage = overflowStorage();
unsigned totalLength = storageHeader(storage).totalLength;
unsigned namedLength = m_table->length();
if (i < namedLength)
return preciseIndexMaskPtr(i, totalLength, &m_scope->variableAt(m_table->get(i)))->get();
return preciseIndexMaskPtr(i, totalLength, storage + (i - namedLength))->get();
}
void setIndexQuickly(VM& vm, uint32_t i, JSValue value)
{
ASSERT_WITH_SECURITY_IMPLICATION(isMappedArgument(i));
WriteBarrier<Unknown>* storage = overflowStorage();
unsigned totalLength = storageHeader(storage).totalLength;
unsigned namedLength = m_table->length();
if (i < namedLength)
preciseIndexMaskPtr(i, totalLength, &m_scope->variableAt(m_table->get(i)))->set(vm, m_scope.get(), value);
else
preciseIndexMaskPtr(i, totalLength, storage + (i - namedLength))->set(vm, this, value);
}
JSFunction* callee()
{
return m_callee.get();
}
bool overrodeThings() const { return storageHeader().overrodeThings; }
void overrideThings(VM&);
void overrideThingsIfNecessary(VM&);
void unmapArgument(VM&, uint32_t index);
void initModifiedArgumentsDescriptorIfNecessary(VM& vm)
{
GenericArguments<ScopedArguments>::initModifiedArgumentsDescriptorIfNecessary(vm, m_table->length());
}
void setModifiedArgumentDescriptor(VM& vm, unsigned index)
{
GenericArguments<ScopedArguments>::setModifiedArgumentDescriptor(vm, index, m_table->length());
}
bool isModifiedArgumentDescriptor(unsigned index)
{
return GenericArguments<ScopedArguments>::isModifiedArgumentDescriptor(index, m_table->length());
}
void copyToArguments(ExecState*, VirtualRegister firstElementDest, unsigned offset, unsigned length);
DECLARE_INFO;
static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
static ptrdiff_t offsetOfStorage() { return OBJECT_OFFSETOF(ScopedArguments, m_storage); }
static ptrdiff_t offsetOfOverrodeThingsInStorage() { return OBJECT_OFFSETOF(StorageHeader, overrodeThings) - sizeof(WriteBarrier<Unknown>); }
static ptrdiff_t offsetOfTotalLengthInStorage() { return OBJECT_OFFSETOF(StorageHeader, totalLength) - sizeof(WriteBarrier<Unknown>); }
static ptrdiff_t offsetOfTable() { return OBJECT_OFFSETOF(ScopedArguments, m_table); }
static ptrdiff_t offsetOfScope() { return OBJECT_OFFSETOF(ScopedArguments, m_scope); }
static size_t allocationSize(size_t inlineSize)
{
RELEASE_ASSERT(!inlineSize);
return sizeof(ScopedArguments);
}
static size_t storageSize(Checked<size_t> capacity)
{
return (sizeof(WriteBarrier<Unknown>) * (capacity + static_cast<size_t>(1))).unsafeGet();
}
static size_t storageHeaderSize() { return sizeof(WriteBarrier<Unknown>); }
private:
struct StorageHeader {
unsigned totalLength;
bool overrodeThings; };
WriteBarrier<Unknown>* overflowStorage() const
{
return m_storage.get().unpoisoned();
}
static StorageHeader& storageHeader(WriteBarrier<Unknown>* storage)
{
static_assert(sizeof(StorageHeader) <= sizeof(WriteBarrier<Unknown>), "StorageHeader needs to be no bigger than a JSValue");
return *bitwise_cast<StorageHeader*>(storage - 1);
}
StorageHeader& storageHeader() const
{
return storageHeader(overflowStorage());
}
template<typename T>
using PoisonedBarrier = PoisonedWriteBarrier<ScopedArgumentsPoison, T>;
PoisonedBarrier<JSFunction> m_callee;
PoisonedBarrier<ScopedArgumentsTable> m_table;
PoisonedBarrier<JSLexicalEnvironment> m_scope;
AuxiliaryBarrier<Poisoned<ScopedArgumentsPoison, WriteBarrier<Unknown>*>> m_storage;
};
}