Check if Array.prototype.__proto__ has been reset to null.

BUG=v8:1121
TEST=test/mjsunit/regress/regress-1121.js

Review URL: http://codereview.chromium.org/6454004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6691 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/builtins.cc

@@ -368,7 +368,9 @@ static bool ArrayPrototypeHasNoElements(Context* global_context,
   array_proto = JSObject::cast(array_proto->GetPrototype());
   ASSERT(array_proto->elements() == Heap::empty_fixed_array());
   // Object.prototype
-  array_proto = JSObject::cast(array_proto->GetPrototype());
+  Object* proto = array_proto->GetPrototype();
+  if (proto == Heap::null_value()) return false;
+  array_proto = JSObject::cast(proto);
   if (array_proto != global_context->initial_object_prototype()) return false;
   if (array_proto->elements() != Heap::empty_fixed_array()) return false;
   ASSERT(array_proto->GetPrototype()->IsNull());

test/mjsunit/regress/regress-1121.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.
+
+// See: http://code.google.com/p/v8/issues/detail?id=1121
+
+// Test that changing Array.prototype.__proto__ keeps Array functions working.
+
+Array.prototype.__proto__ = null;
+// pop has custom call generator, so we need some beefier function.
+assertEquals([1, 2, 3], [1, 2, 3].slice());