CSE2410 Fall 2014 Bounce

// 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 --expose-gc

// TODO(mstarzinger): This test does not succeed when GCs happen in

// between prototype transitions, we disable GC stress for now.

// Flags: --noincremental-marking

// 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);

    // After we add all those properties it went slow mode again :-(

    assertFalse(%HasFastProperties(proto));

  }

  if (same_map_as && !add_first) {

    assertTrue(%HaveSameMap(same_map_as, proto));

  }

  return proto;

}

// TODO(mstarzinger): This test fails easily if gc happens at the wrong time.

gc();

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);

}

var x = {a: 1, b: 2, c: 3};

var o = { __proto__: x };

assertTrue(%HasFastProperties(x));

for (key in x) {

  assertTrue(key == 'a');

  break;

}

delete x.b;

for (key in x) {

  assertTrue(key == 'a');

  break;

}

assertFalse(%HasFastProperties(x));

x.d = 4;

assertFalse(%HasFastProperties(x));

for (key in x) {

  assertTrue(key == 'a');

  break;

}