Follow-up for "Enable loads and stores to global vars through property cell...

Follow-up for "Enable loads and stores to global vars through property cell shortcuts installed into parent script context."

Review URL: https://codereview.chromium.org/1236523004

Cr-Commit-Position: refs/heads/master@{#29651}

src/runtime/runtime-object.cc

@@ -432,8 +432,11 @@ RUNTIME_FUNCTION(Runtime_LoadGlobalViaContext) {
 
   Handle<GlobalObject> global(script_context->global_object());
 
-  LookupIterator it(global, name, LookupIterator::OWN);
-  if (LookupIterator::DATA == it.state()) {
+  LookupIterator it(global, name, LookupIterator::HIDDEN);
+  // Switch to fast mode only if there is a data property and it's not on
+  // a hidden prototype.
+  if (LookupIterator::DATA == it.state() &&
+      it.GetHolder<Object>()->IsJSGlobalObject()) {
     // Now update cell in the script context.
     Handle<PropertyCell> cell = it.GetPropertyCell();
     script_context->set(index, *cell);
@@ -464,8 +467,11 @@ RUNTIME_FUNCTION(Runtime_StoreGlobalViaContext) {
 
   Handle<GlobalObject> global(script_context->global_object());
 
-  LookupIterator it(global, name, LookupIterator::OWN);
-  if (LookupIterator::DATA == it.state()) {
+  LookupIterator it(global, name, LookupIterator::HIDDEN);
+  // Switch to fast mode only if there is a data property and it's not on
+  // a hidden prototype.
+  if (LookupIterator::DATA == it.state() &&
+      it.GetHolder<Object>()->IsJSGlobalObject()) {
     // Now update cell in the script context.
     Handle<PropertyCell> cell = it.GetPropertyCell();
     script_context->set(index, *cell);

test/cctest/test-serialize.cc

@@ -628,7 +628,11 @@ UNINITIALIZED_DEPENDENT_TEST(CustomContextDeserialization,
       root =
           deserializer.DeserializePartial(isolate, global_proxy,
                                           &outdated_contexts).ToHandleChecked();
-      CHECK_EQ(3, outdated_contexts->length());
+      if (FLAG_global_var_shortcuts) {
+        CHECK_EQ(5, outdated_contexts->length());
+      } else {
+        CHECK_EQ(3, outdated_contexts->length());
+      }
       CHECK(root->IsContext());
       Handle<Context> context = Handle<Context>::cast(root);
       CHECK(context->global_proxy() == *global_proxy);