Revert r11681 https://chromiumcodereview.appspot.com/10448011

test/mjsunit/fast-prototype.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: --allow-natives-syntax
-
-// Check that objects that are used for prototypes are in the fast mode.
-
-function Super() {
-}
-
-
-function Sub() {
-}
-
-
-function AddProps(obj) {
-  for (var i = 0; i < 26; i++) {
-    obj["x" + i] = 0;
-  }
-}
-
-
-function DoProtoMagic(proto, set__proto__) {
-  if (set__proto__) {
-    (new Sub()).__proto__ = proto;
-  } else {
-    Sub.prototype = proto;
-  }
-}
-
-
-function test(use_new, add_first, set__proto__, same_map_as) {
-  var proto = use_new ? new Super() : {};
-
-  // New object is fast.
-  assertTrue(%HasFastProperties(proto));
-
-  if (add_first) {
-    AddProps(proto);
-    // Adding this many properties makes it slow.
-    assertFalse(%HasFastProperties(proto));
-    DoProtoMagic(proto, set__proto__);
-    // Making it a prototype makes it fast again.
-    assertTrue(%HasFastProperties(proto));
-  } else {
-    DoProtoMagic(proto, set__proto__);
-    // Still fast
-    assertTrue(%HasFastProperties(proto));
-    AddProps(proto);
-    // Setting the bit means it is still fast with all these properties.
-    assertTrue(%HasFastProperties(proto));
-  }
-  if (same_map_as && !add_first) {
-    assertTrue(%HaveSameMap(same_map_as, proto));
-  }
-  return proto;
-}
-
-
-for (var i = 0; i < 4; i++) {
-  var set__proto__ = ((i & 1) != 0);
-  var use_new = ((i & 2) != 0);
-
-  test(use_new, true, set__proto__);
-
-  var last = test(use_new, false, set__proto__);
-  test(use_new, false, set__proto__, last);
-}