1 /*
 2  * Copyright (c) 1997, 2025, 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 "oops/markWord.hpp"
26 #include "runtime/basicLock.inline.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_shift + markWord::klass_bits == 64);
33 // The hash (preceding klass bits) shall be a direct neighbor but not interleave
34 STATIC_ASSERT(markWord::klass_shift == markWord::hash_bits + markWord::hash_shift);
35 #endif
36 
37 markWord markWord::displaced_mark_helper() const {
38   assert(has_displaced_mark_helper(), "check");
39   // Make sure we have an inflated monitor.
40   guarantee(has_monitor(), "bad header=" INTPTR_FORMAT, value());
41   ObjectMonitor* monitor = this->monitor();
42   return monitor->header();
43 }
44 
45 void markWord::set_displaced_mark_helper(markWord m) const {
46   assert(has_displaced_mark_helper(), "check");
47   // Make sure we have an inflated monitor.
48   guarantee(has_monitor(), "bad header=" INTPTR_FORMAT, value());
49   ObjectMonitor* monitor = this->monitor();
50   monitor->set_header(m);
51 }
52 
53 void markWord::print_on(outputStream* st, bool print_monitor_info) const {
54   if (is_marked()) {  // last bits = 11
55     st->print(" marked(" INTPTR_FORMAT ")", value());
56   } else if (has_monitor()) {  // last bits = 10
57     // have to check has_monitor() before is_locked()
58     st->print(" monitor(" INTPTR_FORMAT ")=", value());
59     if (print_monitor_info && !UseObjectMonitorTable) {
60       ObjectMonitor* mon = monitor();
61       if (mon == nullptr) {
62         st->print("null (this should never be seen!)");
63       } else {
64         mon->print_on(st);
65       }
66     }
67   } else if (is_locked()) {  // last bits != 01 => 00
68     // thin locked
69     st->print(" locked(" INTPTR_FORMAT ")", value());
70   } else {
71     st->print(" mark(");
72     if (is_unlocked()) {   // last bits = 01
73       st->print("is_unlocked");
74       if (has_no_hash()) {
75         st->print(" no_hash");
76       } else {
77         st->print(" hash=" INTPTR_FORMAT, hash());
78       }
79     } else {
80       st->print("??");
81     }
82     st->print(" age=%d)", age());
83   }
84 }