1 /*
2 * Copyright (c) 1997, 2023, 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
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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.
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23 */
24
25 #ifndef SHARE_OOPS_OOP_INLINE_HPP
26 #define SHARE_OOPS_OOP_INLINE_HPP
27
28 #include "oops/oop.hpp"
29
30 #include "memory/universe.hpp"
31 #include "memory/iterator.inline.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/compressedOops.inline.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/markWord.hpp"
38 #include "oops/oopsHierarchy.hpp"
39 #include "runtime/atomic.hpp"
40 #include "runtime/globals.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/debug.hpp"
43 #include "utilities/macros.hpp"
44 #include "utilities/globalDefinitions.hpp"
45
46 // Implementation of all inlined member functions defined in oop.hpp
47 // We need a separate file to avoid circular references
48
49 markWord oopDesc::mark() const {
50 return Atomic::load(&_mark);
51 }
52
53 markWord oopDesc::mark_acquire() const {
54 return Atomic::load_acquire(&_mark);
55 }
56
57 markWord* oopDesc::mark_addr() const {
58 return (markWord*) &_mark;
59 }
60
61 void oopDesc::set_mark(markWord m) {
62 Atomic::store(&_mark, m);
63 }
64
65 void oopDesc::set_mark(HeapWord* mem, markWord m) {
66 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(markWord m) {
70 Atomic::release_store(&_mark, m);
71 }
72
73 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
74 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
78 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
79 }
80
81 void oopDesc::init_mark() {
82 set_mark(markWord::prototype());
83 }
84
85 Klass* oopDesc::klass() const {
86 if (UseCompressedClassPointers) {
87 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
88 } else {
89 return _metadata._klass;
90 }
91 }
92
93 Klass* oopDesc::klass_or_null() const {
94 if (UseCompressedClassPointers) {
95 return CompressedKlassPointers::decode(_metadata._compressed_klass);
96 } else {
97 return _metadata._klass;
98 }
99 }
100
101 Klass* oopDesc::klass_or_null_acquire() const {
102 if (UseCompressedClassPointers) {
103 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
104 return CompressedKlassPointers::decode(nklass);
105 } else {
106 return Atomic::load_acquire(&_metadata._klass);
107 }
108 }
109
110 Klass* oopDesc::klass_raw() const {
111 if (UseCompressedClassPointers) {
112 return CompressedKlassPointers::decode_raw(_metadata._compressed_klass);
113 } else {
114 return _metadata._klass;
115 }
116 }
117
118 void oopDesc::set_klass(Klass* k) {
119 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
120 if (UseCompressedClassPointers) {
121 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
122 } else {
123 _metadata._klass = k;
124 }
125 }
126
127 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
128 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
129 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
130 if (UseCompressedClassPointers) {
131 Atomic::release_store((narrowKlass*)raw_mem,
132 CompressedKlassPointers::encode_not_null(k));
133 } else {
134 Atomic::release_store((Klass**)raw_mem, k);
135 }
136 }
137
138 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
139 if (UseCompressedClassPointers) {
140 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
141 }
142 }
143
144 bool oopDesc::is_a(Klass* k) const {
145 return klass()->is_subtype_of(k);
146 }
147
148 size_t oopDesc::size() {
149 return size_given_klass(klass());
150 }
151
152 size_t oopDesc::size_given_klass(Klass* klass) {
153 int lh = klass->layout_helper();
154 size_t s;
155
156 // lh is now a value computed at class initialization that may hint
157 // at the size. For instances, this is positive and equal to the
158 // size. For arrays, this is negative and provides log2 of the
159 // array element size. For other oops, it is zero and thus requires
160 // a virtual call.
161 //
162 // We go to all this trouble because the size computation is at the
163 // heart of phase 2 of mark-compaction, and called for every object,
164 // alive or dead. So the speed here is equal in importance to the
165 // speed of allocation.
166
167 if (lh > Klass::_lh_neutral_value) {
168 if (!Klass::layout_helper_needs_slow_path(lh)) {
169 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
170 } else {
171 s = klass->oop_size(this);
172 }
173 } else if (lh <= Klass::_lh_neutral_value) {
174 // The most common case is instances; fall through if so.
175 if (lh < Klass::_lh_neutral_value) {
176 // Second most common case is arrays. We have to fetch the
177 // length of the array, shift (multiply) it appropriately,
178 // up to wordSize, add the header, and align to object size.
179 size_t size_in_bytes;
180 size_t array_length = (size_t) ((arrayOop)this)->length();
181 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
182 size_in_bytes += Klass::layout_helper_header_size(lh);
183
184 // This code could be simplified, but by keeping array_header_in_bytes
185 // in units of bytes and doing it this way we can round up just once,
186 // skipping the intermediate round to HeapWordSize.
187 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
188
189 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
190 } else {
191 // Must be zero, so bite the bullet and take the virtual call.
192 s = klass->oop_size(this);
193 }
194 }
195
196 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
197 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
198 return s;
199 }
200
201 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
202 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
203 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
204 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
205 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
206 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
207
208 template<typename T>
209 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
210
211 template <typename T>
212 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
213
214 template <DecoratorSet decorators>
215 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
216 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
217
218 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
219 template <DecoratorSet decorators>
220 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
221
222 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
223 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
224
225 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
226 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
227
228 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
229 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
230 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
231 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
232 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
233 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
234
235 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
236 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
237
238 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
239 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
240
241 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
242 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
243
244 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
245 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
246
247 bool oopDesc::is_locked() const {
248 return mark().is_locked();
249 }
250
251 bool oopDesc::is_unlocked() const {
252 return mark().is_unlocked();
253 }
254
255 // Used only for markSweep, scavenging
256 bool oopDesc::is_gc_marked() const {
257 return mark().is_marked();
258 }
259
260 // Used by scavengers
261 bool oopDesc::is_forwarded() const {
262 // The extra heap check is needed since the obj might be locked, in which case the
263 // mark would point to a stack location and have the sentinel bit cleared
264 return mark().is_marked();
265 }
266
267 // Used by scavengers
268 void oopDesc::forward_to(oop p) {
269 markWord m = markWord::encode_pointer_as_mark(p);
270 assert(m.decode_pointer() == p, "encoding must be reversible");
271 set_mark(m);
272 }
273
274 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
275 markWord m = markWord::encode_pointer_as_mark(p);
276 assert(m.decode_pointer() == p, "encoding must be reversible");
277 markWord old_mark = cas_set_mark(m, compare, order);
278 if (old_mark == compare) {
279 return nullptr;
280 } else {
281 return cast_to_oop(old_mark.decode_pointer());
282 }
283 }
284
285 // Note that the forwardee is not the same thing as the displaced_mark.
286 // The forwardee is used when copying during scavenge and mark-sweep.
287 // It does need to clear the low two locking- and GC-related bits.
288 oop oopDesc::forwardee() const {
289 assert(is_forwarded(), "only decode when actually forwarded");
290 return cast_to_oop(mark().decode_pointer());
291 }
292
293 // The following method needs to be MT safe.
294 uint oopDesc::age() const {
295 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
296 if (has_displaced_mark()) {
297 return displaced_mark().age();
298 } else {
299 return mark().age();
300 }
301 }
302
303 void oopDesc::incr_age() {
304 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
305 if (has_displaced_mark()) {
306 set_displaced_mark(displaced_mark().incr_age());
307 } else {
308 set_mark(mark().incr_age());
309 }
310 }
311
312 template <typename OopClosureType>
313 void oopDesc::oop_iterate(OopClosureType* cl) {
314 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
315 }
316
317 template <typename OopClosureType>
318 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
319 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
320 }
321
322 template <typename OopClosureType>
323 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
324 Klass* k = klass();
325 size_t size = size_given_klass(k);
326 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
327 return size;
328 }
329
330 template <typename OopClosureType>
331 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
332 Klass* k = klass();
333 size_t size = size_given_klass(k);
334 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
335 return size;
336 }
337
338 template <typename OopClosureType>
339 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
340 oop_iterate_backwards(cl, klass());
341 }
342
343 template <typename OopClosureType>
344 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
345 assert(k == klass(), "wrong klass");
346 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
347 }
348
349 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
350 return obj == nullptr || obj->klass()->is_subtype_of(klass);
351 }
352
353 intptr_t oopDesc::identity_hash() {
354 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
355 // Note: The mark must be read into local variable to avoid concurrent updates.
356 markWord mrk = mark();
357 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
358 return mrk.hash();
359 } else if (mrk.is_marked()) {
360 return mrk.hash();
361 } else {
362 return slow_identity_hash();
363 }
364 }
365
366 // This checks fast simple case of whether the oop has_no_hash,
367 // to optimize JVMTI table lookup.
368 bool oopDesc::fast_no_hash_check() {
369 markWord mrk = mark_acquire();
370 assert(!mrk.is_marked(), "should never be marked");
371 return mrk.is_unlocked() && mrk.has_no_hash();
372 }
373
374 bool oopDesc::has_displaced_mark() const {
375 return mark().has_displaced_mark_helper();
376 }
377
378 markWord oopDesc::displaced_mark() const {
379 return mark().displaced_mark_helper();
380 }
381
382 void oopDesc::set_displaced_mark(markWord m) {
383 mark().set_displaced_mark_helper(m);
384 }
385
386 bool oopDesc::mark_must_be_preserved() const {
387 return mark_must_be_preserved(mark());
388 }
389
390 bool oopDesc::mark_must_be_preserved(markWord m) const {
391 return m.must_be_preserved(this);
392 }
393
394 #endif // SHARE_OOPS_OOP_INLINE_HPP