[strong] Implement per-object restrictions behaviour of property freezing

src/v8natives.js

 // 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.
 
 var $functionSourceString;
 var $globalEval;
 var $objectDefineArrayProperty;
 var $objectGetOwnPropertyDescriptor;
 var $toCompletePropertyDescriptor;
 
@@ skipping 664 matching lines @@
         // Step 9a
         if (IsDataDescriptor(current) != IsDataDescriptor(desc)) {
           if (should_throw) {
             throw MakeTypeError(kRedefineDisallowed, p);
           } else {
             return false;
           }
         }
         // Step 10a
         if (IsDataDescriptor(current) && IsDataDescriptor(desc)) {
-          if (!current.isWritable() && desc.isWritable()) {
-            if (should_throw) {
-              throw MakeTypeError(kRedefineDisallowed, p);
-            } else {
-              return false;
+          var currentIsWritable = current.isWritable();
+          if (currentIsWritable != desc.isWritable()) {
+            if (!currentIsWritable || IS_STRONG(obj)) {
+              if (should_throw) {
+                throw currentIsWritable
+                    ? MakeTypeError(kStrongRedefineDisallowed, obj, p)
+                    : MakeTypeError(kRedefineDisallowed, p);
+              } else {
+                return false;
+              }
             }
           }
-          if (!current.isWritable() && desc.hasValue() &&
+          if (!currentIsWritable && desc.hasValue() &&
               !$sameValue(desc.getValue(), current.getValue())) {
             if (should_throw) {
               throw MakeTypeError(kRedefineDisallowed, p);
             } else {
               return false;
             }
           }
         }
         // Step 11
         if (IsAccessorDescriptor(desc) && IsAccessorDescriptor(current)) {
@@ skipping 513 matching lines @@
     %ObjectSeal(obj);
   }
   return obj;
 }
 
 
 // ES5 section 15.2.3.9.
 function ObjectFreezeJS(obj) {
   if (!IS_SPEC_OBJECT(obj)) return obj;
   var isProxy = %_IsJSProxy(obj);
-  if (isProxy || %HasSloppyArgumentsElements(obj) || %IsObserved(obj)) {
+  // TODO(conradw): Investigate modifying the fast path to accommodate strong
+  // objects.
+  if (isProxy || %HasSloppyArgumentsElements(obj) || %IsObserved(obj) ||
+      IS_STRONG(obj)) {
     if (isProxy) {
       ProxyFix(obj);
     }
     var names = ObjectGetOwnPropertyNames(obj);
     for (var i = 0; i < names.length; i++) {
       var name = names[i];
       var desc = GetOwnPropertyJS(obj, name);
       if (desc.isWritable() || desc.isConfigurable()) {
         if (IsDataDescriptor(desc)) desc.setWritable(false);
         desc.setConfigurable(false);
@@ skipping 620 matching lines @@
   to.ObjectGetOwnPropertyKeys = ObjectGetOwnPropertyKeys;
   to.ObjectHasOwnProperty = ObjectHasOwnProperty;
   to.ObjectIsFrozen = ObjectIsFrozen;
   to.ObjectIsSealed = ObjectIsSealed;
   to.ObjectToString = ObjectToString;
   to.OwnPropertyKeys = OwnPropertyKeys;
   to.ToNameArray = ToNameArray;
 });
 
 })