Use LookupIterator for elements in the observed part of DefineAccessor

BUG=v8:4137
LOG=n

Review URL: https://codereview.chromium.org/1177103003

Cr-Commit-Position: refs/heads/master@{#28963}

src/objects.cc

@@ -6396,21 +6396,6 @@ MaybeHandle<Object> JSObject::DefineAccessor(Handle<JSObject> object,
                                              Handle<Object> setter,
                                              PropertyAttributes attributes) {
   Isolate* isolate = object->GetIsolate();
-  // Check access rights if needed.
-  if (object->IsAccessCheckNeeded() && !isolate->MayAccess(object)) {
-    isolate->ReportFailedAccessCheck(object);
-    RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
-    return isolate->factory()->undefined_value();
-  }
-
-  if (object->IsJSGlobalProxy()) {
-    PrototypeIterator iter(isolate, object);
-    if (iter.IsAtEnd()) return isolate->factory()->undefined_value();
-    DCHECK(PrototypeIterator::GetCurrent(iter)->IsJSGlobalObject());
-    DefineAccessor(Handle<JSObject>::cast(PrototypeIterator::GetCurrent(iter)),
-                   name, getter, setter, attributes);
-    return isolate->factory()->undefined_value();
-  }
 
   // Make sure that the top context does not change when doing callbacks or
   // interceptor calls.
@@ -6420,39 +6405,36 @@ MaybeHandle<Object> JSObject::DefineAccessor(Handle<JSObject> object,
   if (name->IsString()) name = String::Flatten(Handle<String>::cast(name));
 
   uint32_t index = 0;
-  bool is_element = name->AsArrayIndex(&index);
+  LookupIterator::Configuration c = LookupIterator::HIDDEN_SKIP_INTERCEPTOR;
+  LookupIterator it = name->AsArrayIndex(&index)
+                          ? LookupIterator(isolate, object, index, c)
+                          : LookupIterator(object, name, c);
+
+  if (it.state() == LookupIterator::ACCESS_CHECK) {
+    if (!it.HasAccess()) {
+      isolate->ReportFailedAccessCheck(it.GetHolder<JSObject>());
+      RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate, Object);
+      return isolate->factory()->undefined_value();
+    }
+    it.Next();
+  }
 
   Handle<Object> old_value = isolate->factory()->the_hole_value();
   bool is_observed = object->map()->is_observed() &&
                      !isolate->IsInternallyUsedPropertyName(name);
   bool preexists = false;
   if (is_observed) {
-    if (is_element) {
-      Maybe<bool> maybe = HasOwnElement(object, index);
-      // Workaround for a GCC 4.4.3 bug which leads to "‘preexists’ may be used
-      // uninitialized in this function".
-      if (!maybe.IsJust()) {
-        DCHECK(false);
-        return isolate->factory()->undefined_value();
-      }
-      preexists = maybe.FromJust();
-      if (preexists && GetOwnElementAccessorPair(object, index).is_null()) {
-        old_value =
-            Object::GetElement(isolate, object, index).ToHandleChecked();
-      }
-    } else {
-      LookupIterator it(object, name, LookupIterator::HIDDEN_SKIP_INTERCEPTOR);
-      CHECK(GetPropertyAttributes(&it).IsJust());
-      preexists = it.IsFound();
-      if (preexists && (it.state() == LookupIterator::DATA ||
-                        it.GetAccessors()->IsAccessorInfo())) {
-        old_value = GetProperty(&it).ToHandleChecked();
-      }
+    CHECK(GetPropertyAttributes(&it).IsJust());
+    preexists = it.IsFound();
+    if (preexists && (it.state() == LookupIterator::DATA ||
+                      it.GetAccessors()->IsAccessorInfo())) {
+      old_value = GetProperty(&it).ToHandleChecked();
     }
   }
 
-  if (is_element) {
-    DefineElementAccessor(object, index, getter, setter, attributes);
+  if (it.IsElement()) {
+    DefineElementAccessor(it.GetStoreTarget(), index, getter, setter,
+                          attributes);
   } else {
     DCHECK(getter->IsSpecFunction() || getter->IsUndefined() ||
            getter->IsNull());
@@ -6460,11 +6442,6 @@ MaybeHandle<Object> JSObject::DefineAccessor(Handle<JSObject> object,
            setter->IsNull());
     // At least one of the accessors needs to be a new value.
     DCHECK(!getter->IsNull() || !setter->IsNull());
-    LookupIterator it(object, name, LookupIterator::OWN_SKIP_INTERCEPTOR);
-    if (it.state() == LookupIterator::ACCESS_CHECK) {
-      // We already did an access check before. We do have access.
-      it.Next();
-    }
     if (!getter->IsNull()) {
       it.TransitionToAccessorProperty(ACCESSOR_GETTER, getter, attributes);
     }