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28 // Regression test of a very rare corner case where left-trimming an
29 // array caused invalid marking bit patterns on lazily swept pages.
31 // Lazy sweeping was deprecated. We are keeping the test case to make
32 // sure that concurrent sweeping, which relies on similar assumptions
33 // as lazy sweeping works correctly.
35 // Flags: --expose-gc --noincremental-marking
38 var head = new Array(1);
41 // Fill heap to increase old-space size and trigger concurrent sweeping on
42 // some of the old-space pages.
43 for (var i = 0; i < 200; i++) {
44 tail[1] = new Array(1000);
47 array = new Array(100);
50 // At this point "array" should have been promoted to old-space and be
51 // located in a concurrently swept page with intact marking bits. Now shift
52 // the array to trigger left-trimming operations.
53 assertEquals(100, array.length);
54 for (var i = 0; i < 50; i++) {
57 assertEquals(50, array.length);
59 // At this point "array" should have been trimmed from the left with
60 // marking bits being correctly transfered to the new object start.
61 // Scavenging operations cause concurrent sweeping to advance and verify
62 // that marking bit patterns are still sane.
63 for (var i = 0; i < 200; i++) {
64 tail[1] = new Array(1000);