Fix missing writebarrier in ArraySplice builtin.

Review URL: http://codereview.chromium.org/6883227

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7706 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/builtins.cc

@@ -838,8 +838,8 @@ BUILTIN(ArraySplice) {
       const int delta = actual_delete_count - item_count;
 
       if (actual_start > 0) {
-        Object** start = elms->data_start();
-        memmove(start + delta, start, actual_start * kPointerSize);
+        AssertNoAllocation no_gc;
+        MoveElements(heap, &no_gc, elms, delta, elms, 0, actual_start);
       }
 
       elms = LeftTrimFixedArray(heap, elms, delta);

test/mjsunit/regress/splice-missing-wb.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.
+
+// Flags: --expose-gc
+
+// Create array large enough to span several page regions.
+var a = new Array(500);
+
+// Fill it with values.
+for (var i = 0; i < a.length; i++) a[i] = {idx:i};
+
+// Force it into oldspace.
+gc();
+gc();
+
+// Array should be in old space now. Store young object into array.
+// Region will be marked.
+a[0] = {idx:0};
+
+// Delete elements a[2] .. a[201]. Internally we will use
+// trimming of backing store. a[0] a[1] will be moved to
+// memory location previously occupied by a[200] a[201].
+a.splice(2, 200);
+
+// Force gc and heap verification.
+gc();
+
+// Try accessing a[0].idx. It will segfault if write-barrier was accidentally
+// omitted.
+assertEquals(0, a[0].idx);
+assertEquals(1, a[1].idx);
+assertEquals(202, a[2].idx);