Merge verbatim descriptors from other (the descriptor of the map being updated) rather than this (d…

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.
 
-#include "hydrogen-sce.h"
-#include "v8.h"
+var extend = function (d, b) {
+  function __() { this.constructor = d; }
+  __.prototype = b.prototype;
+  d.prototype = new __();
+};
 
-namespace v8 {
-namespace internal {
+var Car = (function (Super) {
+  var Car = function () {
+    var self = this;
 
-void HStackCheckEliminationPhase::Run() {
-  // For each loop block walk the dominator tree from the backwards branch to
-  // the loop header. If a call instruction is encountered the backwards branch
-  // is dominated by a call and the stack check in the backwards branch can be
-  // removed.
-  for (int i = 0; i < graph()->blocks()->length(); i++) {
-    HBasicBlock* block = graph()->blocks()->at(i);
-    if (block->IsLoopHeader()) {
-      HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
-      HBasicBlock* dominator = back_edge;
-      while (true) {
-        for (HInstructionIterator it(dominator); !it.Done(); it.Advance()) {
-          if (it.Current()->IsCall()) {
-            block->loop_information()->stack_check()->Eliminate();
-            break;
-          }
+    Super.call(self);
+
+    Object.defineProperties(self, {
+      "make": {
+        enumerable: true,
+        configurable: true,
+        get: function () {
+          return "Ford";
         }
+      }
+    });
 
-        // Done when the loop header is processed.
-        if (dominator == block) break;
+    self.copy = function () {
+      throw new Error("Meant to be overriden");
+    };
 
-        // Move up the dominator tree.
-        dominator = dominator->dominator();
+    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;
+        }
       }
-    }
-  }
-}
+    });
 
-} }  // namespace v8::internal
+    // 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);