Always transition empty FAST_DOUBLE_ARRAYs on push

R=mstarzinger@chromium.org
BUG=chromium:128018
TEST=test/mjsunit/regress/regress-128018.js

Review URL: https://chromiumcodereview.appspot.com/10387130

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11570 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/builtins.cc

@@ -412,14 +412,12 @@ static inline MaybeObject* EnsureJSArrayWithWritableFastElements(
   HeapObject* elms = array->elements();
   Map* map = elms->map();
   if (map == heap->fixed_array_map()) {
-    if (array->HasFastElements()) return elms;
-    if (args == NULL) {
-      if (array->HasFastDoubleElements()) {
-        ASSERT(elms == heap->empty_fixed_array());
-        MaybeObject* maybe_transition =
-            array->TransitionElementsKind(FAST_ELEMENTS);
-        if (maybe_transition->IsFailure()) return maybe_transition;
-      }
+    if (args == NULL || array->HasFastElements()) return elms;
+    if (array->HasFastDoubleElements()) {
+      ASSERT(elms == heap->empty_fixed_array());
+      MaybeObject* maybe_transition =
+          array->TransitionElementsKind(FAST_ELEMENTS);
+      if (maybe_transition->IsFailure()) return maybe_transition;
       return elms;
     }
   } else if (map == heap->fixed_cow_array_map()) {

test/mjsunit/regress/regress-128018.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.
+
+// Flags: --expose-gc
+
+function KeyedStoreIC(a) { a[(1)] = Math.E; }
+var literal = [1.2];
+literal.length = 0;
+literal.push('0' && 0 );
+KeyedStoreIC(literal);
+gc();