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: --expose-gc 29 30 // Create a transition tree A (no descriptors) -> B (descriptor for a) -> C 31 // (descriptor for a and c), that all share the descriptor array [a,c]. C is the 32 // owner of the descriptor array. 33 var o = {}; 34 o.a = 1; 35 o.c = 2; 36 37 // Add a transition B -> D where D has its own descriptor array [a,b] where b is 38 // a constant function. 39 var o1 = {}; 40 o1.a = 1; 41 42 // Install an enumeration cache in the descriptor array [a,c] at map B. 43 for (var x in o1) { } 44 o1.b = function() { return 1; }; 45 46 // Return ownership of the descriptor array [a,c] to B and trim it to [a]. 47 o = null; 48 gc(); 49 50 // Convert the transition B -> D into a transition to B -> E so that E uses the 51 // instance descriptors [a,b] with b being a field. 52 var o2 = {}; 53 o2.a = 1; 54 o2.b = 10; 55 56 // Create an object with map B and iterate over it. 57 var o3 = {}; 58 o3.a = 1; 59 60 for (var y in o3) { } 61
