Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 1 | // Copyright 2012 the V8 project authors. All rights reserved. |
Steve Block | 1e0659c | 2011-05-24 12:43:12 +0100 | [diff] [blame] | 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 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 28 | // Flags: --expose-gc |
Steve Block | 1e0659c | 2011-05-24 12:43:12 +0100 | [diff] [blame] | 29 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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; |
Ben Murdoch | e0cee9b | 2011-05-25 10:26:03 +0100 | [diff] [blame] | 36 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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; |
Ben Murdoch | 85b7179 | 2012-04-11 18:30:58 +0100 | [diff] [blame] | 41 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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; }; |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 45 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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) { } |