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 if (set__proto__) { 50 (new Sub()).__proto__ = proto; 51 } else { 52 Sub.prototype = proto; 53 // Need to instantiate Sub to mark .prototype as prototype. 54 new Sub(); 55 } 56 } 57 58 59 function test(use_new, add_first, set__proto__, same_map_as) { 60 var proto = use_new ? new Super() : {}; 61 62 // New object is fast. 63 assertTrue(%HasFastProperties(proto)); 64 65 if (add_first) { 66 AddProps(proto); 67 // Adding this many properties makes it slow. 68 assertFalse(%HasFastProperties(proto)); 69 DoProtoMagic(proto, set__proto__); 70 // Making it a prototype makes it fast again. 71 assertTrue(%HasFastProperties(proto)); 72 } else { 73 DoProtoMagic(proto, set__proto__); 74 // Still fast 75 assertTrue(%HasFastProperties(proto)); 76 AddProps(proto); 77 if (set__proto__) { 78 // After we add all those properties it went slow mode again :-( 79 assertFalse(%HasFastProperties(proto)); 80 } else { 81 // .prototype keeps it fast. 82 assertTrue(%HasFastProperties(proto)); 83 } 84 } 85 if (same_map_as && !add_first && set__proto__) { 86 assertTrue(%HaveSameMap(same_map_as, proto)); 87 } 88 return proto; 89 } 90 91 // TODO(mstarzinger): This test fails easily if gc happens at the wrong time. 92 gc(); 93 94 for (var i = 0; i < 4; i++) { 95 var set__proto__ = ((i & 1) != 0); 96 var use_new = ((i & 2) != 0); 97 98 test(use_new, true, set__proto__); 99 100 var last = test(use_new, false, set__proto__); 101 test(use_new, false, set__proto__, last); 102 } 103 104 105 var x = {a: 1, b: 2, c: 3}; 106 var o = { __proto__: x }; 107 assertTrue(%HasFastProperties(x)); 108 for (key in x) { 109 assertTrue(key == 'a'); 110 break; 111 } 112 delete x.b; 113 for (key in x) { 114 assertTrue(key == 'a'); 115 break; 116 } 117 assertFalse(%HasFastProperties(x)); 118 x.d = 4; 119 assertFalse(%HasFastProperties(x)); 120 for (key in x) { 121 assertTrue(key == 'a'); 122 break; 123 } 124