[runtime] Minor tweaks to LookupIterator for performance

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 89bc3c91c941c765ff346f068f93ce38a9044970..c3399992edc7e64cb298c4fe5b83240ae93cc211 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -4493,8 +4493,7 @@ Maybe<bool> Object::AddDataProperty(LookupIterator* it, Handle<Object> value,
 
   Isolate* isolate = it->isolate();
 
-  if (!receiver->map()->is_extensible() &&
-      (it->IsElement() || !isolate->IsInternallyUsedPropertyName(it->name()))) {
+  if (it->ExtendingNonExtensible(receiver)) {
     RETURN_FAILURE(
         isolate, should_throw,
         NewTypeError(MessageTemplate::kObjectNotExtensible, it->GetName()));
@@ -4527,9 +4526,10 @@ Maybe<bool> Object::AddDataProperty(LookupIterator* it, Handle<Object> value,
   } else {
     // Migrate to the most up-to-date map that will be able to store |value|
     // under it->name() with |attributes|.
-    it->PrepareTransitionToDataProperty(value, attributes, store_mode);
+    it->PrepareTransitionToDataProperty(receiver, value, attributes,
+                                        store_mode);
     DCHECK_EQ(LookupIterator::TRANSITION, it->state());
-    it->ApplyTransitionToDataProperty();
+    it->ApplyTransitionToDataProperty(receiver);
 
     // TODO(verwaest): Encapsulate dictionary handling better.
     if (receiver->map()->is_dictionary_map()) {
@@ -9942,13 +9942,11 @@ Handle<Map> Map::PrepareForDataProperty(Handle<Map> map, int descriptor,
   // Migrate to the newest map before storing the property.
   map = Update(map);
 
-  Handle<DescriptorArray> descriptors(map->instance_descriptors());
-
-  if (descriptors->CanHoldValue(descriptor, *value)) return map;
+  if (map->instance_descriptors()->CanHoldValue(descriptor, *value)) return map;
 
   Isolate* isolate = map->GetIsolate();
   PropertyAttributes attributes =
-      descriptors->GetDetails(descriptor).attributes();
+      map->instance_descriptors()->GetDetails(descriptor).attributes();
   Representation representation = value->OptimalRepresentation();
   Handle<FieldType> type = value->OptimalType(isolate, representation);