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 "cds/cdsConfig.hpp"
26 #include "classfile/altHashing.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "gc/shared/collectedHeap.inline.hpp"
29 #include "gc/shared/gc_globals.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "memory/universe.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/compressedKlass.inline.hpp"
34 #include "oops/compressedOops.inline.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/verifyOopClosure.hpp"
37 #include "runtime/handles.inline.hpp"
38 #include "runtime/javaThread.hpp"
39 #include "runtime/synchronizer.hpp"
40 #include "runtime/lightweightSynchronizer.hpp"
41 #include "utilities/macros.hpp"
42
43 void oopDesc::print_on(outputStream* st) const {
44 if (*((juint*)this) == badHeapWordVal) {
45 st->print_cr("BAD WORD");
46 } else {
47 klass()->oop_print_on(cast_to_oop(this), st);
48 }
49 }
50
51 void oopDesc::print_address_on(outputStream* st) const {
52 st->print("{" PTR_FORMAT "}", p2i(this));
53
54 }
55
56 void oopDesc::print_name_on(outputStream* st) const {
57 if (*((juint*)this) == badHeapWordVal) {
58 st->print_cr("BAD WORD");
59 } else {
60 st->print_cr("%s", klass()->external_name());
61 }
62 }
63
64 void oopDesc::print() { print_on(tty); }
65
66 void oopDesc::print_address() { print_address_on(tty); }
67
68 char* oopDesc::print_string() {
69 stringStream st;
70 print_on(&st);
71 return st.as_string();
72 }
73
74 void oopDesc::print_value() {
75 print_value_on(tty);
76 }
77
78 char* oopDesc::print_value_string() {
79 char buf[100];
80 stringStream st(buf, sizeof(buf));
81 print_value_on(&st);
82 return st.as_string();
83 }
84
85 void oopDesc::print_value_on(outputStream* st) const {
86 oop obj = const_cast<oopDesc*>(this);
87 if (java_lang_String::is_instance(obj)) {
88 java_lang_String::print(obj, st);
89 print_address_on(st);
90 } else {
91 klass()->oop_print_value_on(obj, st);
92 }
93 }
94
95
96 void oopDesc::verify_on(outputStream* st, oopDesc* oop_desc) {
97 if (oop_desc != nullptr) {
98 oop_desc->klass()->oop_verify_on(oop_desc, st);
99 }
100 }
101
102
103 void oopDesc::verify(oopDesc* oop_desc) {
104 verify_on(tty, oop_desc);
105 }
106
107 intptr_t oopDesc::slow_identity_hash() {
108 // slow case; we have to acquire the micro lock in order to locate the header
109 Thread* current = Thread::current();
110 return ObjectSynchronizer::FastHashCode(current, this);
111 }
112
113 // used only for asserts and guarantees
114 bool oopDesc::is_oop(oop obj, bool ignore_mark_word) {
115 if (!Universe::heap()->is_oop(obj)) {
116 return false;
117 }
118
119 // Header verification: the mark is typically non-zero. If we're
120 // at a safepoint, it must not be zero, except when using the new lightweight locking.
121 // Outside of a safepoint, the header could be changing (for example,
122 // another thread could be inflating a lock on this object).
123 if (ignore_mark_word) {
124 return true;
125 }
126 if (obj->mark().value() != 0) {
127 return true;
128 }
129 return LockingMode == LM_LIGHTWEIGHT || !SafepointSynchronize::is_at_safepoint();
130 }
131
132 void oopDesc::initialize_hash_if_necessary(oop obj, Klass* k, markWord m) {
133 assert(UseCompactObjectHeaders, "only with compact object headers");
134 assert(!m.has_displaced_mark_helper(), "must not be displaced header");
135 assert(m.is_hashed_not_expanded(), "must be hashed but not moved");
136 assert(!m.is_hashed_expanded(), "must not be moved: " INTPTR_FORMAT, m.value());
137 uint32_t hash = static_cast<uint32_t>(ObjectSynchronizer::get_next_hash(nullptr, obj));
138 int offset = k->hash_offset_in_bytes(cast_to_oop(this), m);
139 assert(offset >= 4, "hash offset must not be in header");
140 #ifndef PRODUCT
141 log_trace(ihash)("Initializing hash for " PTR_FORMAT ", old: " PTR_FORMAT ", hash: %d, offset: %d", p2i(this), p2i(obj), hash, offset);
142 #endif
143 int_field_put(offset, (jint) hash);
144 m = m.set_hashed_expanded();
145 assert(static_cast<uint32_t>(LightweightSynchronizer::get_hash(m, cast_to_oop(this), k)) == hash,
146 "hash must remain the same");
147 assert(m.narrow_klass() != 0, "must not be null");
148 set_mark(m);
149 }
150
151 // used only for asserts and guarantees
152 bool oopDesc::is_oop_or_null(oop obj, bool ignore_mark_word) {
153 return obj == nullptr ? true : is_oop(obj, ignore_mark_word);
154 }
155
156 VerifyOopClosure VerifyOopClosure::verify_oop;
157
158 template <class T> void VerifyOopClosure::do_oop_work(T* p) {
159 oop obj = RawAccess<>::oop_load(p);
160 guarantee(oopDesc::is_oop_or_null(obj), "invalid oop: " PTR_FORMAT, p2i(obj));
161 }
162
163 void VerifyOopClosure::do_oop(oop* p) { VerifyOopClosure::do_oop_work(p); }
164 void VerifyOopClosure::do_oop(narrowOop* p) { VerifyOopClosure::do_oop_work(p); }
165
166 // type test operations that doesn't require inclusion of oop.inline.hpp.
167 bool oopDesc::is_instance_noinline() const { return is_instance(); }
168 bool oopDesc::is_instanceRef_noinline() const { return is_instanceRef(); }
169 bool oopDesc::is_stackChunk_noinline() const { return is_stackChunk(); }
170 bool oopDesc::is_array_noinline() const { return is_array(); }
171 bool oopDesc::is_objArray_noinline() const { return is_objArray(); }
172 bool oopDesc::is_typeArray_noinline() const { return is_typeArray(); }
173
174 #if INCLUDE_CDS_JAVA_HEAP
175 void oopDesc::set_narrow_klass(narrowKlass nk) {
176 assert(CDSConfig::is_dumping_heap(), "Used by CDS only. Do not abuse!");
177 assert(UseCompressedClassPointers, "must be");
178 _metadata._compressed_klass = nk;
179 }
180 #endif
181
182 void* oopDesc::load_oop_raw(oop obj, int offset) {
183 uintptr_t addr = (uintptr_t)(void*)obj + (uint)offset;
184 if (UseCompressedOops) {
185 narrowOop narrow_oop = *(narrowOop*)addr;
186 if (CompressedOops::is_null(narrow_oop)) return nullptr;
187 return (void*)CompressedOops::decode_raw(narrow_oop);
188 } else {
189 return *(void**)addr;
190 }
191 }
192
193 oop oopDesc::obj_field_acquire(int offset) const { return HeapAccess<MO_ACQUIRE>::oop_load_at(as_oop(), offset); }
194
195 void oopDesc::obj_field_put_raw(int offset, oop value) { assert(!UseZGC, "ZGC must use store barriers");
196 RawAccess<>::oop_store_at(as_oop(), offset, value); }
197 void oopDesc::release_obj_field_put(int offset, oop value) { HeapAccess<MO_RELEASE>::oop_store_at(as_oop(), offset, value); }
198 void oopDesc::obj_field_put_volatile(int offset, oop value) { HeapAccess<MO_SEQ_CST>::oop_store_at(as_oop(), offset, value); }
199
200 address oopDesc::address_field(int offset) const { return *field_addr<address>(offset); }
201 address oopDesc::address_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<address>(offset)); }
202
203 void oopDesc::address_field_put(int offset, address value) { *field_addr<address>(offset) = value; }
204 void oopDesc::release_address_field_put(int offset, address value) { Atomic::release_store(field_addr<address>(offset), value); }
205
206 Metadata* oopDesc::metadata_field(int offset) const { return *field_addr<Metadata*>(offset); }
207 void oopDesc::metadata_field_put(int offset, Metadata* value) { *field_addr<Metadata*>(offset) = value; }
208
209 Metadata* oopDesc::metadata_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<Metadata*>(offset)); }
210 void oopDesc::release_metadata_field_put(int offset, Metadata* value) { Atomic::release_store(field_addr<Metadata*>(offset), value); }
211
212 jbyte oopDesc::byte_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jbyte>(offset)); }
213 void oopDesc::release_byte_field_put(int offset, jbyte value) { Atomic::release_store(field_addr<jbyte>(offset), value); }
214
215 jchar oopDesc::char_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jchar>(offset)); }
216 void oopDesc::release_char_field_put(int offset, jchar value) { Atomic::release_store(field_addr<jchar>(offset), value); }
217
218 jboolean oopDesc::bool_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jboolean>(offset)); }
219 void oopDesc::release_bool_field_put(int offset, jboolean value) { Atomic::release_store(field_addr<jboolean>(offset), jboolean(value & 1)); }
220
221 jint oopDesc::int_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jint>(offset)); }
222 void oopDesc::release_int_field_put(int offset, jint value) { Atomic::release_store(field_addr<jint>(offset), value); }
223
224 jshort oopDesc::short_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jshort>(offset)); }
225 void oopDesc::release_short_field_put(int offset, jshort value) { Atomic::release_store(field_addr<jshort>(offset), value); }
226
227 jlong oopDesc::long_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jlong>(offset)); }
228 void oopDesc::release_long_field_put(int offset, jlong value) { Atomic::release_store(field_addr<jlong>(offset), value); }
229
230 jfloat oopDesc::float_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jfloat>(offset)); }
231 void oopDesc::release_float_field_put(int offset, jfloat value) { Atomic::release_store(field_addr<jfloat>(offset), value); }
232
233 jdouble oopDesc::double_field_acquire(int offset) const { return Atomic::load_acquire(field_addr<jdouble>(offset)); }
234 void oopDesc::release_double_field_put(int offset, jdouble value) { Atomic::release_store(field_addr<jdouble>(offset), value); }