[stubs] Further optimize Load/StoreGlobalViaContext stubs.

src/runtime/runtime-object.cc

Index: src/runtime/runtime-object.cc
diff --git a/src/runtime/runtime-object.cc b/src/runtime/runtime-object.cc
index ee607259b903e34fe303c18de7d2abedec4f489d..2adbb579062e167c2b4055c605de3b4fb5dda64e 100644
--- a/src/runtime/runtime-object.cc
+++ b/src/runtime/runtime-object.cc
@@ -418,26 +418,26 @@ RUNTIME_FUNCTION(Runtime_ObjectSeal) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_LoadGlobalViaContext) {
-  HandleScope scope(isolate);
-  DCHECK_EQ(2, args.length());
-  CONVERT_SMI_ARG_CHECKED(slot, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
+namespace {
 
+Object* StoreGlobalViaContext(Isolate* isolate, int slot, Handle<Object> value,
+                              LanguageMode language_mode) {
   // Go up context chain to the script context.
   Handle<Context> script_context(isolate->context()->script_context(), isolate);
   DCHECK(script_context->IsScriptContext());
   DCHECK(script_context->get(slot)->IsPropertyCell());
 
   // Lookup the named property on the global object.
+  Handle<ScopeInfo> scope_info(ScopeInfo::cast(script_context->extension()),
+                               isolate);
+  Handle<Name> name(scope_info->ContextSlotName(slot), isolate);
   Handle<GlobalObject> global_object(script_context->global_object(), isolate);
   LookupIterator it(global_object, name, LookupIterator::HIDDEN);
-
   // Switch to fast mode only if there is a data property and it's not on
   // a hidden prototype.
-  if (it.state() == LookupIterator::DATA &&
+  if (LookupIterator::DATA == it.state() && !it.IsReadOnly() &&
       it.GetHolder<Object>()->IsJSGlobalObject()) {
-    // Now update the cell in the script context.
+    // Now update cell in the script context.
     Handle<PropertyCell> cell = it.GetPropertyCell();
     script_context->set(slot, *cell);
   } else {
@@ -447,29 +447,38 @@ RUNTIME_FUNCTION(Runtime_LoadGlobalViaContext) {
   }
 
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, Object::GetProperty(&it));
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, result,
+      Object::SetProperty(&it, value, language_mode,
+                          Object::CERTAINLY_NOT_STORE_FROM_KEYED));
   return *result;
 }
 
+}  // namespace
 
-namespace {
 
-Object* StoreGlobalViaContext(Isolate* isolate, int slot, Handle<Name> name,
-                              Handle<Object> value,
-                              LanguageMode language_mode) {
+RUNTIME_FUNCTION(Runtime_LoadGlobalViaContext) {
+  HandleScope scope(isolate);
+  DCHECK_EQ(1, args.length());
+  CONVERT_SMI_ARG_CHECKED(slot, 0);
+
   // Go up context chain to the script context.
   Handle<Context> script_context(isolate->context()->script_context(), isolate);
   DCHECK(script_context->IsScriptContext());
   DCHECK(script_context->get(slot)->IsPropertyCell());
 
   // Lookup the named property on the global object.
+  Handle<ScopeInfo> scope_info(ScopeInfo::cast(script_context->extension()),
+                               isolate);
+  Handle<Name> name(scope_info->ContextSlotName(slot), isolate);
   Handle<GlobalObject> global_object(script_context->global_object(), isolate);
   LookupIterator it(global_object, 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.IsReadOnly() &&
       it.GetHolder<Object>()->IsJSGlobalObject()) {
-    // Now update cell in the script context.
+    // Now update the cell in the script context.
     Handle<PropertyCell> cell = it.GetPropertyCell();
     script_context->set(slot, *cell);
   } else {
@@ -479,35 +488,28 @@ Object* StoreGlobalViaContext(Isolate* isolate, int slot, Handle<Name> name,
   }
 
   Handle<Object> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result,
-      Object::SetProperty(&it, value, language_mode,
-                          Object::CERTAINLY_NOT_STORE_FROM_KEYED));
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, Object::GetProperty(&it));
   return *result;
 }
 
-}  // namespace
-
 
 RUNTIME_FUNCTION(Runtime_StoreGlobalViaContext_Sloppy) {
   HandleScope scope(isolate);
-  DCHECK_EQ(3, args.length());
+  DCHECK_EQ(2, args.length());
   CONVERT_SMI_ARG_CHECKED(slot, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
-  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
 
-  return StoreGlobalViaContext(isolate, slot, name, value, SLOPPY);
+  return StoreGlobalViaContext(isolate, slot, value, SLOPPY);
 }
 
 
 RUNTIME_FUNCTION(Runtime_StoreGlobalViaContext_Strict) {
   HandleScope scope(isolate);
-  DCHECK_EQ(3, args.length());
+  DCHECK_EQ(2, args.length());
   CONVERT_SMI_ARG_CHECKED(slot, 0);
-  CONVERT_ARG_HANDLE_CHECKED(Name, name, 1);
-  CONVERT_ARG_HANDLE_CHECKED(Object, value, 2);
+  CONVERT_ARG_HANDLE_CHECKED(Object, value, 1);
 
-  return StoreGlobalViaContext(isolate, slot, name, value, STRICT);
+  return StoreGlobalViaContext(isolate, slot, value, STRICT);
 }