Merge verbatim descriptors from other (the descriptor of the map being...

Merge verbatim descriptors from other (the descriptor of the map being updated) rather than this (descriptors of the most updated map found in the transition tree).

BUG=v8:2863
R=svenpanne@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23676003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16396 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.cc

@@ -7817,7 +7817,7 @@ MaybeObject* DescriptorArray::Merge(int verbatim,
   int current_offset = 0;
   for (descriptor = 0; descriptor < verbatim; descriptor++) {
     if (GetDetails(descriptor).type() == FIELD) current_offset++;
-    result->CopyFrom(descriptor, this, descriptor, witness);
+    result->CopyFrom(descriptor, other, descriptor, witness);
   }
 
   // |verbatim| -> |valid|

test/mjsunit/regress/regress-merge-descriptors.js

+// Copyright 2013 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 extend = function (d, b) {
+  function __() { this.constructor = d; }
+  __.prototype = b.prototype;
+  d.prototype = new __();
+};
+
+var Car = (function (Super) {
+  var Car = function () {
+    var self = this;
+
+    Super.call(self);
+
+    Object.defineProperties(self, {
+      "make": {
+        enumerable: true,
+        configurable: true,
+        get: function () {
+          return "Ford";
+        }
+      }
+    });
+
+    self.copy = function () {
+      throw new Error("Meant to be overriden");
+    };
+
+    return self;
+  };
+
+  extend(Car, Super);
+
+  return Car;
+}(Object));
+
+
+var SuperCar = ((function (Super) {
+  var SuperCar = function (make) {
+    var self = this;
+
+    Super.call(self);
+
+
+    Object.defineProperties(self, {
+      "make": {
+        enumerable: true,
+        configurable: true,
+        get: function () {
+          return make;
+        }
+      }
+    });
+
+    // Convert self.copy from CONSTANT to FIELD.
+    self.copy = function () { };
+
+    return self;
+  };
+  extend(SuperCar, Super);
+  return SuperCar;
+})(Car));
+
+assertEquals("Ford", new Car().make);
+assertEquals("Bugatti", new SuperCar("Bugatti").make);
+assertEquals("Lambo", new SuperCar("Lambo").make);
+assertEquals("Shelby", new SuperCar("Shelby").make);