ES6 Unscopables

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 28481383a5fbd846a6940deb9a1b08ee64dab56e..6f0488011f278b4b3255c11bbc739ad16501d836 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -9214,6 +9214,58 @@ static Object* ComputeReceiverForNonGlobal(Isolate* isolate,
 }
 
 
+static ObjectPair LoadWithContextSlot(Isolate* isolate, Handle<String> name,
+                                      Handle<JSReceiver> object,
+                                      Handle<Object> receiver_handle) {
+  Handle<JSReceiver> object_receiver = object;
+  Handle<Symbol> unscopables_symbol(
+      isolate->native_context()->unscopables_symbol(), isolate);
+
+  while (true) {
+    PropertyAttributes name_attrs =
+        JSReceiver::GetOwnPropertyAttributes(object, name);
+
+    if (name_attrs != ABSENT) {
+      PropertyAttributes unscopables_attrs =
+          JSReceiver::GetOwnPropertyAttributes(object, unscopables_symbol);
+      PropertyAttributes blocked_attrs = ABSENT;
+      if (unscopables_attrs != ABSENT) {
+        Handle<Object> unscopables_object;
+        ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+            isolate, unscopables_object,
+            Object::GetProperty(object, unscopables_symbol),
+            MakePair(isolate->heap()->exception(), NULL));
+
+        if (unscopables_object->IsSpecObject()) {
+          blocked_attrs = JSReceiver::GetOwnPropertyAttributes(
+              Handle<JSReceiver>::cast(unscopables_object), name);
+        }
+      }
+
+      if (blocked_attrs == ABSENT) {
+        Handle<Object> value;
+        ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+            isolate, value,
+            Object::GetPropertyWithReceiver(object, object_receiver, name),
+            MakePair(isolate->heap()->exception(), NULL));
+        return MakePair(*value, *receiver_handle);
+      }
+    }
+
+    Object* prototype = object->GetPrototype();
+    if (prototype->IsNull()) {
+      break;
+    }
+    ASSERT(prototype->IsSpecObject());
+    object = handle(JSReceiver::cast(prototype), isolate);
+  }
+
+  // The property doesn't exist - return undefined.
+  return MakePair(isolate->heap()->undefined_value(),
+                  isolate->heap()->undefined_value());
+}
+
+
 static ObjectPair LoadContextSlotHelper(Arguments args,
                                         Isolate* isolate,
                                         bool throw_error) {
@@ -9288,6 +9340,10 @@ static ObjectPair LoadContextSlotHelper(Arguments args,
                 : ComputeReceiverForNonGlobal(isolate, JSObject::cast(*object)),
         isolate);
 
+    if (FLAG_harmony_unscopables && context->IsWithContext()) {
+      return LoadWithContextSlot(isolate, name, object, receiver_handle);
+    }
+
     // No need to unhole the value here.  This is taken care of by the
     // GetProperty function.
     Handle<Object> value;