1 /*
2 * Copyright (c) 2022, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef SHARE_RUNTIME_LOCKSTACK_INLINE_HPP
27 #define SHARE_RUNTIME_LOCKSTACK_INLINE_HPP
28
29 #include "memory/iterator.hpp"
30 #include "runtime/lockStack.hpp"
31 #include "runtime/safepoint.hpp"
32 #include "runtime/stackWatermark.hpp"
33 #include "runtime/stackWatermarkSet.inline.hpp"
34 #include "runtime/thread.hpp"
35
36 inline int LockStack::to_index(uint32_t offset) {
37 return (offset - lock_stack_base_offset) / oopSize;
38 }
39
40 JavaThread* LockStack::get_thread() const {
41 char* addr = reinterpret_cast<char*>(const_cast<LockStack*>(this));
42 return reinterpret_cast<JavaThread*>(addr - lock_stack_offset);
43 }
44
45 inline bool LockStack::can_push() const {
46 return to_index(_top) < CAPACITY;
47 }
48
49 inline bool LockStack::is_owning_thread() const {
50 JavaThread* thread = JavaThread::current();
51 bool is_owning = &thread->lock_stack() == this;
52 assert(is_owning == (get_thread() == thread), "is_owning sanity");
53 return is_owning;
54 }
55
56 inline void LockStack::push(oop o) {
57 verify("pre-push");
58 assert(oopDesc::is_oop(o), "must be");
59 assert(!contains(o), "entries must be unique");
60 assert(can_push(), "must have room");
61 assert(_base[to_index(_top)] == NULL, "expect zapped entry");
62 _base[to_index(_top)] = o;
63 _top += oopSize;
64 verify("post-push");
65 }
66
67 inline oop LockStack::pop() {
68 verify("pre-pop");
69 assert(to_index(_top) > 0, "underflow, probably unbalanced push/pop");
70 _top -= oopSize;
71 oop o = _base[to_index(_top)];
72 #ifdef ASSERT
73 _base[to_index(_top)] = NULL;
74 #endif
75 assert(!contains(o), "entries must be unique: " PTR_FORMAT, p2i(o));
76 verify("post-pop");
77 return o;
78 }
79
80 inline void LockStack::remove(oop o) {
81 verify("pre-remove");
82 assert(contains(o), "entry must be present: " PTR_FORMAT, p2i(o));
83 int end = to_index(_top);
84 for (int i = 0; i < end; i++) {
85 if (_base[i] == o) {
86 int last = end - 1;
87 for (; i < last; i++) {
88 _base[i] = _base[i + 1];
89 }
90 _top -= oopSize;
91 #ifdef ASSERT
92 _base[to_index(_top)] = NULL;
93 #endif
94 break;
95 }
96 }
97 assert(!contains(o), "entries must be unique: " PTR_FORMAT, p2i(o));
98 verify("post-remove");
99 }
100
101 inline bool LockStack::contains(oop o) const {
102 verify("pre-contains");
103 if (!SafepointSynchronize::is_at_safepoint() && !is_owning_thread()) {
104 // When a foreign thread inspects this thread's lock-stack, it may see
105 // bad references here when a concurrent collector has not gotten
106 // to processing the lock-stack, yet. Call StackWaterMark::start_processing()
107 // to ensure that all references are valid.
108 StackWatermark* watermark = StackWatermarkSet::get(get_thread(), StackWatermarkKind::gc);
109 if (watermark != NULL) {
110 watermark->start_processing();
111 }
112 }
113 int end = to_index(_top);
114 for (int i = end - 1; i >= 0; i--) {
115 if (_base[i] == o) {
116 verify("post-contains");
117 return true;
118 }
119 }
120 verify("post-contains");
121 return false;
122 }
123
124 inline void LockStack::oops_do(OopClosure* cl) {
125 verify("pre-oops-do");
126 int end = to_index(_top);
127 for (int i = 0; i < end; i++) {
128 cl->do_oop(&_base[i]);
129 }
130 verify("post-oops-do");
131 }
132
133 #endif // SHARE_RUNTIME_LOCKSTACK_INLINE_HPP