| // Copyright 2011 the V8 project authors. All rights reserved. |
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| // |
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| |
| // Regression test of a very rare corner case where left-trimming an |
| // array caused invalid marking bit patterns on lazily swept pages. |
| |
| // Flags: --expose-gc --noincremental-marking --max-new-space-size 1000 |
| |
| (function() { |
| var head = new Array(1); |
| var tail = head; |
| |
| // Fill heap to increase old-space size and trigger lazy sweeping on |
| // some of the old-space pages. |
| for (var i = 0; i < 200; i++) { |
| tail[1] = new Array(1000); |
| tail = tail[1]; |
| } |
| array = new Array(100); |
| gc(); gc(); |
| |
| // At this point "array" should have been promoted to old-space and be |
| // located in a lazy swept page with intact marking bits. Now shift |
| // the array to trigger left-trimming operations. |
| assertEquals(100, array.length); |
| for (var i = 0; i < 50; i++) { |
| array.shift(); |
| } |
| assertEquals(50, array.length); |
| |
| // At this point "array" should have been trimmed from the left with |
| // marking bits being correctly transfered to the new object start. |
| // Scavenging operations cause lazy sweeping to advance and verify |
| // that marking bit patterns are still sane. |
| for (var i = 0; i < 200; i++) { |
| tail[1] = new Array(1000); |
| tail = tail[1]; |
| } |
| })(); |