First cut at bug 992

src/runtime.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 3482 matching lines @@
     int index = Smi::cast(args[1])->value();
     Handle<Object> result = GetCharAt(str, index);
     return *result;
   }
 
   // Fall back to GetObjectProperty.
   return Runtime::GetObjectProperty(args.at<Object>(0),
                                     args.at<Object>(1));
 }
 
-
+// Implements part of 8.12.9 DefineOwnProperty.
+// There are 3 cases that lead here:
+// Step 4b - define a new accessor property.
+// Steps 9c & 12 - replace an existing data property with an accessor property.
+// Step 12 - update an existing accessor property with an accessor or generic
+//           descriptor.
 static MaybeObject* Runtime_DefineOrRedefineAccessorProperty(Arguments args) {
   ASSERT(args.length() == 5);
   HandleScope scope;
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   CONVERT_CHECKED(String, name, args[1]);
   CONVERT_CHECKED(Smi, flag_setter, args[2]);
   Object* fun = args[3];
   RUNTIME_ASSERT(fun->IsJSFunction() || fun->IsUndefined());
   CONVERT_CHECKED(Smi, flag_attr, args[4]);
   int unchecked = flag_attr->value();
@@ skipping 11 matching lines @@
        || result.type() == CONSTANT_FUNCTION)) {
     Object* ok;
     { MaybeObject* maybe_ok =
           obj->DeleteProperty(name, JSObject::NORMAL_DELETION);
       if (!maybe_ok->ToObject(&ok)) return maybe_ok;
     }
   }
   return obj->DefineAccessor(name, flag_setter->value() == 0, fun, attr);
 }
 
+// Implements part of 8.12.9 DefineOwnProperty.
+// There are 3 cases that lead here:
+// Step 4a - define a new data property.
+// Steps 9b & 12 - replace an existing accessor property with a data property.
+// Step 12 - update an existing data property with a data or generic
+//           descriptor.
 static MaybeObject* Runtime_DefineOrRedefineDataProperty(Arguments args) {
   ASSERT(args.length() == 4);
   HandleScope scope;
   CONVERT_ARG_CHECKED(JSObject, js_object, 0);
   CONVERT_ARG_CHECKED(String, name, 1);
   Handle<Object> obj_value = args.at<Object>(2);
 
   CONVERT_CHECKED(Smi, flag, args[3]);
   int unchecked = flag->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
 
   PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
 
   // Check if this is an element.
   uint32_t index;
   bool is_element = name->AsArrayIndex(&index);
 
   // Special case for elements if any of the flags are true.
   // If elements are in fast case we always implicitly assume that:
   // DONT_DELETE: false, DONT_ENUM: false, READ_ONLY: false.
   if (((unchecked & (DONT_DELETE | DONT_ENUM | READ_ONLY)) != 0) &&
       is_element) {
     // Normalize the elements to enable attributes on the property.
-    NormalizeElements(js_object);
+    if (!js_object->IsJSGlobalProxy()) {
+      NormalizeElements(js_object);
+    }
     Handle<NumberDictionary> dictionary(js_object->element_dictionary());
     // Make sure that we never go back to fast case.
     dictionary->set_requires_slow_elements();
     PropertyDetails details = PropertyDetails(attr, NORMAL);
     NumberDictionarySet(dictionary, index, obj_value, details);
   }
 
   LookupResult result;
   js_object->LookupRealNamedProperty(*name, &result);
 
   // Take special care when attributes are different and there is already
   // a property. For simplicity we normalize the property which enables us
   // to not worry about changing the instance_descriptor and creating a new
   // map. The current version of SetObjectProperty does not handle attributes
   // correctly in the case where a property is a field and is reset with
   // new attributes.
   if (result.IsProperty() &&
       (attr != result.GetAttributes() || result.type() == CALLBACKS)) {
     // New attributes - normalize to avoid writing to instance descriptor
-    NormalizeProperties(js_object, CLEAR_INOBJECT_PROPERTIES, 0);
+    if (!js_object->IsJSGlobalProxy()) {
+      NormalizeProperties(js_object, CLEAR_INOBJECT_PROPERTIES, 0);
+    }
     // Use IgnoreAttributes version since a readonly property may be
     // overridden and SetProperty does not allow this.
     return js_object->SetLocalPropertyIgnoreAttributes(*name,
                                                        *obj_value,
                                                        attr);
   }
 
   return Runtime::SetObjectProperty(js_object, name, obj_value, attr);
 }
 
@@ skipping 7285 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal