Mercurial > hg > truffle
comparison src/share/vm/oops/markOop.inline.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | 37f87013dfd8 |
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1 /* | |
2 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved. | |
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 // Should this header be preserved during GC? | |
26 inline bool markOopDesc::must_be_preserved_with_bias(oop obj_containing_mark) const { | |
27 assert(UseBiasedLocking, "unexpected"); | |
28 if (has_bias_pattern()) { | |
29 // Will reset bias at end of collection | |
30 // Mark words of biased and currently locked objects are preserved separately | |
31 return false; | |
32 } | |
33 markOop prototype_header = prototype_for_object(obj_containing_mark); | |
34 if (prototype_header->has_bias_pattern()) { | |
35 // Individual instance which has its bias revoked; must return | |
36 // true for correctness | |
37 return true; | |
38 } | |
39 return (!is_unlocked() || !has_no_hash()); | |
40 } | |
41 | |
42 // Should this header (including its age bits) be preserved in the | |
43 // case of a promotion failure during scavenge? | |
44 inline bool markOopDesc::must_be_preserved_with_bias_for_promotion_failure(oop obj_containing_mark) const { | |
45 assert(UseBiasedLocking, "unexpected"); | |
46 // We don't explicitly save off the mark words of biased and | |
47 // currently-locked objects during scavenges, so if during a | |
48 // promotion failure we encounter either a biased mark word or a | |
49 // klass which still has a biasable prototype header, we have to | |
50 // preserve the mark word. This results in oversaving, but promotion | |
51 // failures are rare, and this avoids adding more complex logic to | |
52 // the scavengers to call new variants of | |
53 // BiasedLocking::preserve_marks() / restore_marks() in the middle | |
54 // of a scavenge when a promotion failure has first been detected. | |
55 if (has_bias_pattern() || | |
56 prototype_for_object(obj_containing_mark)->has_bias_pattern()) { | |
57 return true; | |
58 } | |
59 return (this != prototype()); | |
60 } | |
61 | |
62 // Should this header (including its age bits) be preserved in the | |
63 // case of a scavenge in which CMS is the old generation? | |
64 inline bool markOopDesc::must_be_preserved_with_bias_for_cms_scavenge(klassOop klass_of_obj_containing_mark) const { | |
65 assert(UseBiasedLocking, "unexpected"); | |
66 // CMS scavenges preserve mark words in similar fashion to promotion failures; see above | |
67 if (has_bias_pattern() || | |
68 klass_of_obj_containing_mark->klass_part()->prototype_header()->has_bias_pattern()) { | |
69 return true; | |
70 } | |
71 return (this != prototype()); | |
72 } | |
73 | |
74 inline markOop markOopDesc::prototype_for_object(oop obj) { | |
75 #ifdef ASSERT | |
76 markOop prototype_header = obj->klass()->klass_part()->prototype_header(); | |
77 assert(prototype_header == prototype() || prototype_header->has_bias_pattern(), "corrupt prototype header"); | |
78 #endif | |
79 return obj->klass()->klass_part()->prototype_header(); | |
80 } |