ObjectPropertyConditionSet generateConditionsForInstanceOf(
VM& vm, JSCell* owner, ExecState* exec, Structure* headStructure, JSObject* prototype,
bool shouldHit)
{
bool didHit = false;
if (ObjectPropertyConditionSetInternal::verbose)
dataLog("Searching for prototype ", JSValue(prototype), " starting with structure ", RawPointer(headStructure), " with shouldHit = ", shouldHit, "\n");
ObjectPropertyConditionSet result = generateConditions(
vm, exec->lexicalGlobalObject(), headStructure, shouldHit ? prototype : nullptr,
[&] (Vector<ObjectPropertyCondition>& conditions, JSObject* object) -> bool {
if (ObjectPropertyConditionSetInternal::verbose)
dataLog("Encountered object: ", RawPointer(object), "\n");
if (object == prototype) {
RELEASE_ASSERT(shouldHit);
didHit = true;
return true;
}
Structure* structure = object->structure(vm);
if (structure->hasPolyProto())
return false;
conditions.append(
ObjectPropertyCondition::hasPrototype(
vm, owner, object, structure->storedPrototypeObject()));
return true;
});
if (result.isValid()) {
if (ObjectPropertyConditionSetInternal::verbose)
dataLog("didHit = ", didHit, ", shouldHit = ", shouldHit, "\n");
RELEASE_ASSERT(didHit == shouldHit);
}
return result;
}
std::unique_ptr<PolyProtoAccessChain> PolyProtoAccessChain::create(JSGlobalObject* globalObject, JSCell* base, JSObject* target, bool& usesPolyProto)
{
JSCell* current = base;
VM& vm = *base->vm();
bool found = false;
usesPolyProto = false;
std::unique_ptr<PolyProtoAccessChain> result(new PolyProtoAccessChain());
for (unsigned iterationNumber = 0; true; ++iterationNumber) {
Structure* structure = current->structure(vm);
if (!structure->propertyAccessesAreCacheable())
return nullptr;
if (structure->isProxy())
return nullptr;
if (structure->isDictionary()) {
ASSERT(structure->isObject());
if (structure->hasBeenFlattenedBefore())
return nullptr;
structure->flattenDictionaryStructure(vm, asObject(current));
}
// To save memory, we don't include the base in the chain. We let
// AccessCase provide the base to us as needed.
if (iterationNumber)
result->m_chain.append(structure);
else
RELEASE_ASSERT(current == base);
if (current == target) {
found = true;
break;
}
// We only have poly proto if we need to access our prototype via
// the poly proto protocol. If the slot base is the only poly proto
// thing in the chain, and we have a cache hit on it, then we're not
// poly proto.
usesPolyProto |= structure->hasPolyProto();
JSValue prototype = structure->prototypeForLookup(globalObject, current);
if (prototype.isNull())
break;
current = asObject(prototype);
}
if (!found && !!target)
return nullptr;
return result;
}