1 /*
2 * Copyright (c) 2022, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "precompiled.hpp"
28 #include "memory/allocation.hpp"
29 #include "oops/markWord.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/globals.hpp"
32 #include "runtime/lockStack.inline.hpp"
33 #include "runtime/objectMonitor.inline.hpp"
34 #include "runtime/safepoint.hpp"
35 #include "runtime/stackWatermark.hpp"
36 #include "runtime/stackWatermarkSet.inline.hpp"
37 #include "runtime/thread.hpp"
38 #include "utilities/copy.hpp"
39 #include "utilities/debug.hpp"
40 #include "utilities/globalDefinitions.hpp"
41 #include "utilities/growableArray.hpp"
42 #include "utilities/ostream.hpp"
43 #include "utilities/sizes.hpp"
44
45 #include <type_traits>
46
47 const int LockStack::lock_stack_offset = in_bytes(JavaThread::lock_stack_offset());
48 const int LockStack::lock_stack_top_offset = in_bytes(JavaThread::lock_stack_top_offset());
49 const int LockStack::lock_stack_base_offset = in_bytes(JavaThread::lock_stack_base_offset());
50
51 LockStack::LockStack(JavaThread* jt) :
52 _top(lock_stack_base_offset), _base() {
53 // Make sure the layout of the object is compatible with the emitted code's assumptions.
54 STATIC_ASSERT(sizeof(_bad_oop_sentinel) == oopSize);
55 STATIC_ASSERT(sizeof(_base[0]) == oopSize);
56 STATIC_ASSERT(std::is_standard_layout<LockStack>::value);
57 STATIC_ASSERT(offsetof(LockStack, _bad_oop_sentinel) == offsetof(LockStack, _base) - oopSize);
58 #ifdef ASSERT
59 for (int i = 0; i < CAPACITY; i++) {
60 _base[i] = nullptr;
61 }
62 #endif
63 }
64
65 uint32_t LockStack::start_offset() {
66 int offset = lock_stack_base_offset;
67 assert(offset > 0, "must be positive offset");
68 return static_cast<uint32_t>(offset);
69 }
70
71 uint32_t LockStack::end_offset() {
72 int offset = lock_stack_base_offset + CAPACITY * oopSize;
73 assert(offset > 0, "must be positive offset");
74 return static_cast<uint32_t>(offset);
75 }
76
77 #ifndef PRODUCT
78 void LockStack::verify(const char* msg) const {
79 assert(LockingMode == LM_LIGHTWEIGHT, "never use lock-stack when light weight locking is disabled");
80 assert((_top <= end_offset()), "lockstack overflow: _top %d end_offset %d", _top, end_offset());
81 assert((_top >= start_offset()), "lockstack underflow: _top %d start_offset %d", _top, start_offset());
82 if (SafepointSynchronize::is_at_safepoint() || (Thread::current()->is_Java_thread() && is_owning_thread())) {
83 int top = to_index(_top);
84 for (int i = 0; i < top; i++) {
85 assert(_base[i] != nullptr, "no zapped before top");
86 if (VM_Version::supports_recursive_lightweight_locking()) {
87 oop o = _base[i];
88 for (; i < top - 1; i++) {
89 // Consecutive entries may be the same
90 if (_base[i + 1] != o) {
91 break;
92 }
93 }
94 }
95
96 for (int j = i + 1; j < top; j++) {
97 assert(_base[i] != _base[j], "entries must be unique: %s", msg);
98 }
99 }
100 for (int i = top; i < CAPACITY; i++) {
101 assert(_base[i] == nullptr, "only zapped entries after top: i: %d, top: %d, entry: " PTR_FORMAT, i, top, p2i(_base[i]));
102 }
103 }
104 }
105 #endif
106
107 #ifdef ASSERT
108 void LockStack::verify_consistent_lock_order(GrowableArray<oop>& lock_order, bool leaf_frame) const {
109 int top_index = to_index(_top);
110 int lock_index = lock_order.length();
111
112 if (!leaf_frame) {
113 // If the lock_order is not from the leaf frame we must search
114 // for the top_index which fits with the most recent fast_locked
115 // objects in the lock stack.
116 while (lock_index-- > 0) {
117 const oop obj = lock_order.at(lock_index);
118 if (contains(obj)) {
119 for (int index = 0; index < top_index; index++) {
120 if (_base[index] == obj) {
121 // Found top index
122 top_index = index + 1;
123 break;
124 }
125 }
126
127 if (VM_Version::supports_recursive_lightweight_locking()) {
128 // With recursive looks there may be more of the same object
129 while (lock_index-- > 0 && lock_order.at(lock_index) == obj) {
130 top_index++;
131 }
132 assert(top_index <= to_index(_top), "too many obj in lock_order");
133 }
134
135 break;
136 }
137 }
138
139 lock_index = lock_order.length();
140 }
141
142 JavaThread* thread = get_thread();
143 Thread* current = Thread::current();
144 while (lock_index-- > 0) {
145 const oop obj = lock_order.at(lock_index);
146 const markWord mark = obj->mark_acquire();
147 assert(obj->is_locked(), "must be locked");
148 ObjectMonitor* monitor = nullptr;
149 if (mark.has_monitor()) {
150 monitor = LightweightSynchronizer::read_monitor(current, obj);
151 }
152 if (top_index > 0 && obj == _base[top_index - 1]) {
153 assert(mark.is_fast_locked() || monitor->is_owner_anonymous(),
154 "must be fast_locked or inflated by other thread");
155 top_index--;
156 } else {
157 assert(!mark.is_fast_locked(), "must be inflated");
158 assert(monitor->owner_raw() == thread ||
159 (!leaf_frame && thread->current_waiting_monitor() == monitor),
160 "must be owned by (or waited on by) thread");
161 assert(!contains(obj), "must not be on lock_stack");
162 }
163 }
164 }
165 #endif
166
167 void LockStack::print_on(outputStream* st) {
168 for (int i = to_index(_top); (--i) >= 0;) {
169 st->print("LockStack[%d]: ", i);
170 oop o = _base[i];
171 if (oopDesc::is_oop(o)) {
172 o->print_on(st);
173 } else {
174 st->print_cr("not an oop: " PTR_FORMAT, p2i(o));
175 }
176 }
177 }
178
179 OMCache::OMCache(JavaThread* jt) : _entries() {
180 STATIC_ASSERT(std::is_standard_layout<OMCache>::value);
181 STATIC_ASSERT(std::is_standard_layout<OMCache::OMCacheEntry>::value);
182 STATIC_ASSERT(offsetof(OMCache, _null_sentinel) == offsetof(OMCache, _entries) +
183 offsetof(OMCache::OMCacheEntry, _oop) +
184 OMCache::CAPACITY * in_bytes(oop_to_oop_difference()));
185 }