Introduce builtin for Array.shift function.

test/mjsunit/array-shift.js

Index: test/mjsunit/array-shift.js
diff --git a/test/mjsunit/array-shift.js b/test/mjsunit/array-shift.js
new file mode 100644
index 0000000000000000000000000000000000000000..43439ab62193d610675d1395f11ea6c4b4b65b09
--- /dev/null
+++ b/test/mjsunit/array-shift.js
@@ -0,0 +1,46 @@
+// Copyright 2010 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.
+
+// Check that shifting array of holes keeps it as array of holes
+(function() {
+  var array = new Array(10);
+  array.shift();
+  assertFalse(0 in array);
+})();
+
+// Now check the case with array of holes and some elements on prototype.
+(function() {
+  var array = new Array(10);
+  Array.prototype[7] = "@7";
+  assertEquals(array[0], undefined);
+  assertEquals(array[7], Array.prototype[7]);
+
+  array.shift();
+
+  assertEquals(array[0], undefined);
+  assertEquals(array[7], Array.prototype[7]);

[Mads Ager (chromium), 2010/02/15 11:10:54]

I guess after shifting array[6] is interesting as well?

+})();