Invalidate the enum cache when converting a transition across which the descriptors are shared.

Review URL: https://chromiumcodereview.appspot.com/11145017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12722 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.cc

@@ -1806,9 +1806,6 @@ MaybeObject* JSObject::ConvertTransitionToMapTransition(
     Map* map;
     DescriptorArray* new_descriptors = new_map->instance_descriptors();
     DescriptorArray* old_descriptors = old_map->instance_descriptors();
-    if (old_descriptors->HasEnumCache()) {
-      new_descriptors->CopyEnumCacheFrom(old_descriptors);
-    }
     for (Object* current = old_map;
          !current->IsUndefined();
          current = map->GetBackPointer()) {
@@ -1816,6 +1813,7 @@ MaybeObject* JSObject::ConvertTransitionToMapTransition(
       if (!map->HasTransitionArray()) break;
       TransitionArray* transitions = map->transitions();
       if (transitions->descriptors() != old_descriptors) break;
+      map->SetEnumLength(Map::kInvalidEnumCache);
       transitions->set_descriptors(new_descriptors);
     }
     old_map->set_owns_descriptors(false);

test/mjsunit/regress/regress-convert-enum2.js

+// Copyright 2012 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.
+
+var o = {};
+o.a = 1;
+o.b = function() { return 1; };
+o.d = 2;
+
+for (var x in o) { }
+
+var o1 = {};
+o1.a = 1;
+o1.b = 10;
+o1.c = 20;
+
+var keys = ["a", "b", "c"];
+
+var i = 0;
+for (var y in o1) {
+  assertEquals(keys[i], y);
+  i += 1;
+}