ES6 Unscopables

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 61e1069d0db35242be66e6f2031c9b098760b064..e33acc75973c29b7246815d557fbc6b3103fe174 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -41,6 +41,7 @@
 #include "src/smart-pointers.h"
 #include "src/string-search.h"
 #include "src/stub-cache.h"
+#include "src/unscopables.h"
 #include "src/uri.h"
 #include "src/v8threads.h"
 #include "src/vm-state-inl.h"
@@ -9132,6 +9133,25 @@ static Object* ComputeReceiverForNonGlobal(Isolate* isolate,
 }
 
 
+static ObjectPair LoadWithContextSlot(Isolate* isolate, Handle<String> name,
+                                      Handle<JSReceiver> object,
+                                      Handle<Object> receiver_handle) {
+  LookupIterator it(object, name);
+  PropertyAttributes attrs = UnscopableLookup(&it);

[Toon Verwaest, 2014/07/25 10:09:41]

An exception could already have been thrown in UnscopableLookup. Check for
has_pending_exception. I suggest returning (at least) Maybe<PropertyAttributes>
to indicate this possibility.

+  if (attrs != ABSENT) {
+    Handle<Object> value;
+    ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+        isolate, value, Object::GetProperty(&it),
+        MakePair(isolate->heap()->exception(), NULL));
+
+    return MakePair(*value, *receiver_handle);
+  }
+
+  return MakePair(isolate->heap()->undefined_value(),
+                  isolate->heap()->undefined_value());
+}
+
+
 static ObjectPair LoadLookupSlotHelper(Arguments args, Isolate* isolate,
                                        bool throw_error) {
   HandleScope scope(isolate);
@@ -9205,6 +9225,10 @@ static ObjectPair LoadLookupSlotHelper(Arguments args, Isolate* isolate,
                 : 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;