[strong] Implement per-object restrictions behaviour of delete operator

src/elements.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arguments.h"
 #include "src/conversions.h"
 #include "src/elements.h"
 #include "src/messages.h"
@@ skipping 1383 matching lines @@
                                      isolate);
     bool is_arguments =
         (obj->GetElementsKind() == SLOPPY_ARGUMENTS_ELEMENTS);
     if (is_arguments) {
       backing_store = handle(FixedArray::cast(backing_store->get(1)), isolate);
     }
     Handle<SeededNumberDictionary> dictionary =
         Handle<SeededNumberDictionary>::cast(backing_store);
     int entry = dictionary->FindEntry(key);
     if (entry != SeededNumberDictionary::kNotFound) {
-      Handle<Object> result =
-          SeededNumberDictionary::DeleteProperty(dictionary, entry);
+      Handle<Object> result = SeededNumberDictionary::DeleteProperty(
+          dictionary, entry, obj->map()->is_strong());

[rossberg, 2015/05/22 14:01:26]

Do we have to pass down the flag here? It seems that if the object is strong,
there is no point in even making the call, and you can immediately set the
result to false right here.

[conradw, 2015/05/27 18:09:32]

Yes, missed this.

       if (*result == *isolate->factory()->false_value()) {
         if (is_strict(language_mode)) {
           // Deleting a non-configurable property in strict mode.
           Handle<Object> name = isolate->factory()->NewNumberFromUint(key);
           THROW_NEW_ERROR(
               isolate,
               NewTypeError(MessageTemplate::kStrictDeleteProperty, name, obj),
               Object);
         }
         return isolate->factory()->false_value();
@@ skipping 433 matching lines @@
       UNREACHABLE();
       break;
   }
 
   array->set_elements(*elms);
   array->set_length(Smi::FromInt(number_of_elements));
   return array;
 }
 
 } }  // namespace v8::internal