1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "oops/markWord.hpp"
27 #include "runtime/javaThread.hpp"
28 #include "runtime/objectMonitor.inline.hpp"
29 #include "utilities/ostream.hpp"
30
31 #ifdef _LP64
32 STATIC_ASSERT((markWord::klass_shadow_mask_inplace & markWord::klass_mask_in_place) == 0);
33 STATIC_ASSERT((markWord::klass_load_shift + markWord::klass_shadow_bits) == markWord::klass_shift);
34 STATIC_ASSERT(markWord::klass_shift + markWord::klass_bits == 64);
35 // The hash (preceding nKlass) shall be a direct neighbor but not interleave
36 STATIC_ASSERT(markWord::klass_shift == markWord::hash_bits_compact + markWord::hash_shift_compact);
37 #endif
38
39 markWord markWord::displaced_mark_helper() const {
40 assert(has_displaced_mark_helper(), "check");
41 if (has_monitor()) {
42 // Has an inflated monitor. Must be checked before has_locker().
43 ObjectMonitor* monitor = this->monitor();
44 return monitor->header();
45 }
46 if (has_locker()) { // has a stack lock
47 BasicLock* locker = this->locker();
48 return locker->displaced_header();
49 }
50 // This should never happen:
51 fatal("bad header=" INTPTR_FORMAT, value());
52 return markWord(value());
53 }
54
55 void markWord::set_displaced_mark_helper(markWord m) const {
56 assert(has_displaced_mark_helper(), "check");
57 if (has_monitor()) {
58 // Has an inflated monitor. Must be checked before has_locker().
59 ObjectMonitor* monitor = this->monitor();
60 monitor->set_header(m);
61 return;
62 }
63 if (has_locker()) { // has a stack lock
64 BasicLock* locker = this->locker();
65 locker->set_displaced_header(m);
66 return;
67 }
68 // This should never happen:
69 fatal("bad header=" INTPTR_FORMAT, value());
70 }
71
72 void markWord::print_on(outputStream* st, bool print_monitor_info) const {
73 if (is_marked()) { // last bits = 11
74 st->print(" marked(" INTPTR_FORMAT ")", value());
75 } else if (has_monitor()) { // last bits = 10
76 // have to check has_monitor() before is_locked()
77 st->print(" monitor(" INTPTR_FORMAT ")=", value());
78 if (print_monitor_info && LockingMode != LM_LIGHTWEIGHT) {
79 // TODO[OMWorld]: Cleanup, even if the monitor read is racy, something should be printed.
80 ObjectMonitor* mon = monitor();
81 if (mon == nullptr) {
82 st->print("null (this should never be seen!)");
83 } else {
84 mon->print_on(st);
85 }
86 }
87 } else if (is_locked()) { // last bits != 01 => 00
88 // thin locked
89 st->print(" locked(" INTPTR_FORMAT ")", value());
90 } else {
91 st->print(" mark(");
92 if (is_unlocked()) { // last bits = 01
93 st->print("is_unlocked");
94 if (has_no_hash()) {
95 st->print(" no_hash");
96 } else {
97 st->print(" hash=" INTPTR_FORMAT, hash());
98 }
99 } else {
100 st->print("??");
101 }
102 st->print(" age=%d)", age());
103 }
104 }