1 /*
2 * Copyright (c) 2019, 2021, 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 #include "precompiled.hpp"
25 #include "classfile/vmClasses.hpp"
26 #include "memory/resourceArea.hpp"
27 #include "memory/universe.hpp"
28 #include "oops/instanceKlass.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/atomic.hpp"
31 #include "runtime/biasedLocking.hpp"
32 #include "runtime/interfaceSupport.inline.hpp"
33 #include "runtime/orderAccess.hpp"
34 #include "runtime/os.hpp"
35 #include "runtime/synchronizer.hpp"
36 #include "runtime/semaphore.inline.hpp"
37 #include "threadHelper.inline.hpp"
38 #include "unittest.hpp"
39 #include "utilities/globalDefinitions.hpp"
40 #include "utilities/ostream.hpp"
41
42 // The test doesn't work for PRODUCT because it needs WizardMode
43 #ifndef PRODUCT
test_pattern(stringStream * st,const char * pattern)44 static bool test_pattern(stringStream* st, const char* pattern) {
45 return (strstr(st->as_string(), pattern) != NULL);
46 }
47
assert_test_pattern(Handle object,const char * pattern)48 static void assert_test_pattern(Handle object, const char* pattern) {
49 stringStream st;
50 object->print_on(&st);
51 ASSERT_TRUE(test_pattern(&st, pattern)) << pattern << " not in " << st.as_string();
52 }
53
assert_not_test_pattern(Handle object,const char * pattern)54 static void assert_not_test_pattern(Handle object, const char* pattern) {
55 stringStream st;
56 object->print_on(&st);
57 ASSERT_FALSE(test_pattern(&st, pattern)) << pattern << " found in " << st.as_string();
58 }
59
60 class LockerThread : public JavaTestThread {
61 oop _obj;
62 public:
LockerThread(Semaphore * post,oop obj)63 LockerThread(Semaphore* post, oop obj) : JavaTestThread(post), _obj(obj) {}
~LockerThread()64 virtual ~LockerThread() {}
65
main_run()66 void main_run() {
67 JavaThread* THREAD = JavaThread::current();
68 HandleMark hm(THREAD);
69 Handle h_obj(THREAD, _obj);
70 ResourceMark rm(THREAD);
71
72 // Wait gets the lock inflated.
73 // The object will stay locked for the context of 'ol' so the lock will
74 // still be inflated after the notify_all() call. Deflation can't happen
75 // while an ObjectMonitor is "busy" and being locked is the most "busy"
76 // state we have...
77 ObjectLocker ol(h_obj, THREAD);
78 ol.notify_all(THREAD);
79 assert_test_pattern(h_obj, "monitor");
80 }
81 };
82
83
TEST_VM(markWord,printing)84 TEST_VM(markWord, printing) {
85 JavaThread* THREAD = JavaThread::current();
86 ThreadInVMfromNative invm(THREAD);
87 ResourceMark rm(THREAD);
88
89 oop obj = vmClasses::Byte_klass()->allocate_instance(THREAD);
90
91 FlagSetting fs(WizardMode, true);
92
93 HandleMark hm(THREAD);
94 Handle h_obj(THREAD, obj);
95
96 if (UseBiasedLocking && BiasedLocking::enabled()) {
97 // Can't test this with biased locking disabled.
98 // Biased locking is initially enabled for this java.lang.Byte object.
99 assert_test_pattern(h_obj, "is_biased");
100
101 // Lock using biased locking.
102 BasicObjectLock lock;
103 lock.set_obj(obj);
104 markWord prototype_header = obj->klass()->prototype_header();
105 markWord mark = obj->mark();
106 markWord biased_mark = markWord::encode((JavaThread*) THREAD, mark.age(), prototype_header.bias_epoch());
107 obj->set_mark(biased_mark);
108 // Look for the biased_locker in markWord, not prototype_header.
109 #ifdef _LP64
110 assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x0000000000000000");
111 #else
112 assert_not_test_pattern(h_obj, "mark(is_biased biased_locker=0x00000000");
113 #endif
114 }
115
116 // Same thread tries to lock it again.
117 {
118 ObjectLocker ol(h_obj, THREAD);
119 assert_test_pattern(h_obj, "locked");
120 }
121
122 // This is no longer biased, because ObjectLocker revokes the bias.
123 assert_test_pattern(h_obj, "is_neutral no_hash");
124
125 // Hash the object then print it.
126 intx hash = h_obj->identity_hash();
127 assert_test_pattern(h_obj, "is_neutral hash=0x");
128
129 // Wait gets the lock inflated.
130 {
131 ObjectLocker ol(h_obj, THREAD);
132
133 Semaphore done(0);
134 LockerThread* st;
135 st = new LockerThread(&done, h_obj());
136 st->doit();
137
138 ol.wait(THREAD);
139 assert_test_pattern(h_obj, "monitor");
140 done.wait_with_safepoint_check(THREAD); // wait till the thread is done.
141 }
142 }
143 #endif // PRODUCT
144