Allow JSObject::PreventExtensions to work for arguments objects.

R=karlklose@chromium.org

Review URL: http://codereview.chromium.org/7335002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8587 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.cc

@@ -3381,23 +3381,22 @@ MaybeObject* JSObject::PreventExtensions() {
   }
 
   // If there are fast elements we normalize.
-  if (HasFastElements()) {
-    MaybeObject* result = NormalizeElements();
-    if (result->IsFailure()) return result;
+  NumberDictionary* dictionary = NULL;
+  { MaybeObject* maybe = NormalizeElements();
+    if (!maybe->To<NumberDictionary>(&dictionary)) return maybe;
   }
-  // TODO(kmillikin): Handle arguments object with dictionary elements.
-  ASSERT(HasDictionaryElements());
+  ASSERT(HasDictionaryElements() || HasDictionaryArgumentsElements());
   // Make sure that we never go back to fast case.
-  element_dictionary()->set_requires_slow_elements();
+  dictionary->set_requires_slow_elements();
 
   // Do a map transition, other objects with this map may still
   // be extensible.
-  Object* new_map;
-  { MaybeObject* maybe_new_map = map()->CopyDropTransitions();
-    if (!maybe_new_map->ToObject(&new_map)) return maybe_new_map;
+  Map* new_map;
+  { MaybeObject* maybe = map()->CopyDropTransitions();
+    if (!maybe->To<Map>(&new_map)) return maybe;
   }
-  Map::cast(new_map)->set_is_extensible(false);
-  set_map(Map::cast(new_map));
+  new_map->set_is_extensible(false);
+  set_map(new_map);
   ASSERT(!map()->is_extensible());
   return new_map;
 }

test/mjsunit/regress/regress-88858.js

+// Copyright 2011 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --expose-gc
+
+// Verify that JSObject::PreventExtensions works for arguments objects.
+
+try {
+    function make_watcher(name) { }
+    var o, p;
+    function f(flag) {
+        if (flag) {
+            o = arguments;
+        } else {
+            p = arguments;
+            o.watch(0, (arguments-1901)('o'));
+            p.watch(0, make_watcher('p'));
+            p.unwatch(0);
+            o.unwatch(0);
+            p[0] = 4;
+            assertEq(flag, 4);
+        }
+    }
+    f(true);
+    f(false);
+    reportCompare(true, true);
+} catch(exc1) { }
+
+try {
+    function __noSuchMethod__() {
+       if (anonymous == "1")
+           return NaN;
+       return __construct__;
+    }
+    f.p = function() { };
+    Object.freeze(p);
+    new new freeze().p;
+    reportCompare(0, 0, "ok");
+} catch(exc2) { }
+
+gc();