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      1 // Copyright 2012 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 // Flags: --allow-natives-syntax --expose-gc
     29 // Flags: --noincremental-marking
     30 
     31 // Check that objects that are used for prototypes are in the fast mode.
     32 
     33 function Super() {
     34 }
     35 
     36 
     37 function Sub() {
     38 }
     39 
     40 
     41 function AddProps(obj) {
     42   for (var i = 0; i < 26; i++) {
     43     obj["x" + i] = 0;
     44   }
     45 }
     46 
     47 
     48 function DoProtoMagic(proto, set__proto__) {
     49   var receiver;
     50   if (set__proto__) {
     51     receiver = new Sub();
     52     receiver.__proto__ = proto;
     53   } else {
     54     Sub.prototype = proto;
     55     // Need to instantiate Sub to mark .prototype as prototype. Make sure the
     56     // instantiated object is used so that the allocation is not optimized away.
     57     receiver = new Sub();
     58   }
     59   // Prototypes are made fast when ICs encounter them.
     60   function ic() { return typeof receiver.foo; }
     61   ic();
     62   ic();
     63 }
     64 
     65 
     66 function test(use_new, add_first, set__proto__) {
     67   var proto = use_new ? new Super() : {};
     68 
     69   // New object is fast.
     70   assertTrue(%HasFastProperties(proto));
     71 
     72   if (add_first) {
     73     AddProps(proto);
     74     // Adding this many properties makes it slow.
     75     assertFalse(%HasFastProperties(proto));
     76     DoProtoMagic(proto, set__proto__);
     77     // Making it a prototype makes it fast again.
     78     assertTrue(%HasFastProperties(proto));
     79   } else {
     80     DoProtoMagic(proto, set__proto__);
     81     // Still fast
     82     assertTrue(%HasFastProperties(proto));
     83     AddProps(proto);
     84     // Still fast.
     85     assertTrue(%HasFastProperties(proto));
     86   }
     87   return proto;
     88 }
     89 
     90 // TODO(mstarzinger): This test fails easily if gc happens at the wrong time.
     91 gc();
     92 
     93 for (var i = 0; i < 4; i++) {
     94   var set__proto__ = ((i & 1) != 0);
     95   var use_new = ((i & 2) != 0);
     96 
     97   test(use_new, true, set__proto__);
     98   test(use_new, false, set__proto__);
     99 }
    100 
    101 
    102 var x = {a: 1, b: 2, c: 3};
    103 var o = { __proto__: x };
    104 assertTrue(%HasFastProperties(x));
    105 for (key in x) {
    106   assertTrue(key == 'a');
    107   break;
    108 }
    109 delete x.b;
    110 for (key in x) {
    111   assertTrue(key == 'a');
    112   break;
    113 }
    114 assertTrue(%HasFastProperties(x));
    115 x.d = 4;
    116 assertTrue(%HasFastProperties(x));
    117 for (key in x) {
    118   assertTrue(key == 'a');
    119   break;
    120 }
    121