Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame^] | 1 | // Copyright 2011 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, |
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| 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 |
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| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | // Regression test of a very rare corner case where left-trimming an |
| 29 | // array caused invalid marking bit patterns on lazily swept pages. |
| 30 | |
| 31 | // Flags: --expose-gc --noincremental-marking --max-new-space-size 1000 |
| 32 | |
| 33 | (function() { |
| 34 | var head = new Array(1); |
| 35 | var tail = head; |
| 36 | |
| 37 | // Fill heap to increase old-space size and trigger lazy sweeping on |
| 38 | // some of the old-space pages. |
| 39 | for (var i = 0; i < 200; i++) { |
| 40 | tail[1] = new Array(1000); |
| 41 | tail = tail[1]; |
| 42 | } |
| 43 | array = new Array(100); |
| 44 | gc(); gc(); |
| 45 | |
| 46 | // At this point "array" should have been promoted to old-space and be |
| 47 | // located in a lazy swept page with intact marking bits. Now shift |
| 48 | // the array to trigger left-trimming operations. |
| 49 | assertEquals(100, array.length); |
| 50 | for (var i = 0; i < 50; i++) { |
| 51 | array.shift(); |
| 52 | } |
| 53 | assertEquals(50, array.length); |
| 54 | |
| 55 | // At this point "array" should have been trimmed from the left with |
| 56 | // marking bits being correctly transfered to the new object start. |
| 57 | // Scavenging operations cause lazy sweeping to advance and verify |
| 58 | // that marking bit patterns are still sane. |
| 59 | for (var i = 0; i < 200; i++) { |
| 60 | tail[1] = new Array(1000); |
| 61 | tail = tail[1]; |
| 62 | } |
| 63 | })(); |