1 /*
2 * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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.
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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).
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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/iterator.inline.hpp"
31 #include "memory/universe.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/compressedKlass.inline.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/markWord.inline.hpp"
38 #include "oops/objLayout.inline.hpp"
39 #include "oops/oopsHierarchy.hpp"
40 #include "runtime/atomicAccess.hpp"
41 #include "runtime/globals.hpp"
42 #include "utilities/align.hpp"
43 #include "utilities/debug.hpp"
44 #include "utilities/globalDefinitions.hpp"
45 #include "utilities/macros.hpp"
46
47 // Implementation of all inlined member functions defined in oop.hpp
48 // We need a separate file to avoid circular references
49
50 void* oopDesc::base_addr() { return this; }
51 const void* oopDesc::base_addr() const { return this; }
52
53 markWord oopDesc::mark() const {
54 return AtomicAccess::load(&_mark);
55 }
56
57 markWord oopDesc::mark_acquire() const {
58 return AtomicAccess::load_acquire(&_mark);
59 }
60
61 void oopDesc::set_mark(markWord m) {
62 AtomicAccess::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(HeapWord* mem, markWord m) {
70 AtomicAccess::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
71 }
72
73 void oopDesc::release_set_mark(markWord m) {
74 AtomicAccess::release_store(&_mark, m);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
78 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark);
79 }
80
81 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
82 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark, order);
83 }
84
85 markWord oopDesc::prototype_mark() const {
86 if (UseCompactObjectHeaders) {
87 return klass()->prototype_header();
88 } else {
89 return markWord::prototype();
90 }
91 }
92
93 void oopDesc::init_mark() {
94 set_mark(prototype_mark());
95 }
96
97 Klass* oopDesc::klass() const {
98 return CompressedKlassPointers::decode_not_null(narrow_klass());
99 }
100
101 Klass* oopDesc::klass_or_null() const {
102 return CompressedKlassPointers::decode(narrow_klass());
103 }
104
105 Klass* oopDesc::klass_or_null_acquire() const {
106 return CompressedKlassPointers::decode(narrow_klass_acquire());
107 }
108
109 Klass* oopDesc::klass_without_asserts() const {
110 return CompressedKlassPointers::decode_without_asserts(narrow_klass());
111 }
112
113 narrowKlass oopDesc::narrow_klass() const {
114 switch (ObjLayout::klass_mode()) {
115 case ObjLayout::Compact:
116 return mark().narrow_klass();
117 case ObjLayout::Compressed:
118 return _compressed_klass;
119 default:
120 ShouldNotReachHere();
121 }
122 }
123
124 narrowKlass oopDesc::narrow_klass_acquire() const {
125 switch (ObjLayout::klass_mode()) {
126 case ObjLayout::Compact:
127 return mark_acquire().narrow_klass();
128 case ObjLayout::Compressed:
129 return AtomicAccess::load_acquire(&_compressed_klass);
130 default:
131 ShouldNotReachHere();
132 }
133 }
134
135 void oopDesc::set_klass(Klass* k) {
136 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
137 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
138 _compressed_klass = CompressedKlassPointers::encode_not_null(k);
139 }
140
141 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
142 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
143 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
144 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
145 AtomicAccess::release_store((narrowKlass*)raw_mem, CompressedKlassPointers::encode_not_null(k));
146 }
147
148 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
149 assert(has_klass_gap(), "precondition");
150 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
151 }
152
153 bool oopDesc::is_a(Klass* k) const {
154 return klass()->is_subtype_of(k);
155 }
156
157 size_t oopDesc::size() {
158 return size_given_klass(klass());
159 }
160
161 size_t oopDesc::size_given_klass(Klass* klass) {
162 int lh = klass->layout_helper();
163 size_t s;
164
165 // lh is now a value computed at class initialization that may hint
166 // at the size. For instances, this is positive and equal to the
167 // size. For arrays, this is negative and provides log2 of the
168 // array element size. For other oops, it is zero and thus requires
169 // a virtual call.
170 //
171 // We go to all this trouble because the size computation is at the
172 // heart of phase 2 of mark-compaction, and called for every object,
173 // alive or dead. So the speed here is equal in importance to the
174 // speed of allocation.
175
176 if (lh > Klass::_lh_neutral_value) {
177 if (!Klass::layout_helper_needs_slow_path(lh)) {
178 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
179 } else {
180 s = klass->oop_size(this);
181 }
182 } else if (lh <= Klass::_lh_neutral_value) {
183 // The most common case is instances; fall through if so.
184 if (lh < Klass::_lh_neutral_value) {
185 // Second most common case is arrays. We have to fetch the
186 // length of the array, shift (multiply) it appropriately,
187 // up to wordSize, add the header, and align to object size.
188 size_t size_in_bytes;
189 size_t array_length = (size_t) ((arrayOop)this)->length();
190 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
191 size_in_bytes += Klass::layout_helper_header_size(lh);
192
193 // This code could be simplified, but by keeping array_header_in_bytes
194 // in units of bytes and doing it this way we can round up just once,
195 // skipping the intermediate round to HeapWordSize.
196 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
197
198 assert(s == klass->oop_size(this), "wrong array object size");
199 } else {
200 // Must be zero, so bite the bullet and take the virtual call.
201 s = klass->oop_size(this);
202 }
203 }
204
205 assert(s > 0, "Oop size must be greater than zero, not %zu", s);
206 assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
207 return s;
208 }
209
210 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
211 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
212 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
213 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
214 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
215 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
216
217 template<typename T>
218 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
219
220 template <typename T>
221 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
222
223 template <DecoratorSet decorators>
224 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
225 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
226
227 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
228 template <DecoratorSet decorators>
229 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
230
231 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
232 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
233
234 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
235 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
236
237 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
238 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
239 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
240 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
241 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
242 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
243
244 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
245 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
246 inline jint oopDesc::int_field_relaxed(int offset) const { return AtomicAccess::load(field_addr<jint>(offset)); }
247 inline void oopDesc::int_field_put_relaxed(int offset, jint value) { AtomicAccess::store(field_addr<jint>(offset), value); }
248
249 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
250 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
251
252 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
253 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
254
255 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
256 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
257
258 bool oopDesc::is_locked() const {
259 return mark().is_locked();
260 }
261
262 bool oopDesc::is_unlocked() const {
263 return mark().is_unlocked();
264 }
265
266 bool oopDesc::is_gc_marked() const {
267 return mark().is_marked();
268 }
269
270 // Used by scavengers
271 bool oopDesc::is_forwarded() const {
272 return mark().is_forwarded();
273 }
274
275 bool oopDesc::is_self_forwarded() const {
276 return mark().is_self_forwarded();
277 }
278
279 // Used by scavengers
280 void oopDesc::forward_to(oop p) {
281 assert(cast_from_oop<oopDesc*>(p) != this,
282 "must not be used for self-forwarding, use forward_to_self() instead");
283 markWord m = markWord::encode_pointer_as_mark(p);
284 assert(m.decode_pointer() == p, "encoding must be reversible");
285 set_mark(m);
286 }
287
288 void oopDesc::forward_to_self() {
289 set_mark(mark().set_self_forwarded());
290 }
291
292 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
293 markWord old_mark = cas_set_mark(new_mark, compare, order);
294 if (old_mark == compare) {
295 return nullptr;
296 } else {
297 assert(old_mark.is_forwarded(), "must be forwarded here");
298 return forwardee(old_mark);
299 }
300 }
301
302 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
303 assert(cast_from_oop<oopDesc*>(p) != this,
304 "must not be used for self-forwarding, use forward_to_self_atomic() instead");
305 markWord m = markWord::encode_pointer_as_mark(p);
306 assert(forwardee(m) == p, "encoding must be reversible");
307 return cas_set_forwardee(m, compare, order);
308 }
309
310 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
311 markWord new_mark = old_mark.set_self_forwarded();
312 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
313 return cas_set_forwardee(new_mark, old_mark, order);
314 }
315
316 oop oopDesc::forwardee(markWord mark) const {
317 assert(mark.is_forwarded(), "only decode when actually forwarded");
318 if (mark.is_self_forwarded()) {
319 return cast_to_oop(this);
320 } else {
321 return mark.forwardee();
322 }
323 }
324
325 // Note that the forwardee is not the same thing as the displaced_mark.
326 // The forwardee is used when copying during scavenge and mark-sweep.
327 // It does need to clear the low two locking- and GC-related bits.
328 oop oopDesc::forwardee() const {
329 return forwardee(mark());
330 }
331
332 void oopDesc::unset_self_forwarded() {
333 set_mark(mark().unset_self_forwarded());
334 }
335
336 // The following method needs to be MT safe.
337 uint oopDesc::age() const {
338 markWord m = mark();
339 assert(!m.is_marked(), "Attempt to read age from forwarded mark");
340 if (m.has_displaced_mark_helper()) {
341 return m.displaced_mark_helper().age();
342 } else {
343 return m.age();
344 }
345 }
346
347 void oopDesc::incr_age() {
348 markWord m = mark();
349 assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
350 if (m.has_displaced_mark_helper()) {
351 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
352 } else {
353 set_mark(m.incr_age());
354 }
355 }
356
357 template <typename OopClosureType>
358 void oopDesc::oop_iterate(OopClosureType* cl) {
359 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
360 }
361
362 template <typename OopClosureType>
363 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
364 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
365 }
366
367 template <typename OopClosureType>
368 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
369 Klass* k = klass();
370 size_t size = size_given_klass(k);
371 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
372 return size;
373 }
374
375 template <typename OopClosureType>
376 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
377 Klass* k = klass();
378 size_t size = size_given_klass(k);
379 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
380 return size;
381 }
382
383 template <typename OopClosureType>
384 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
385 oop_iterate_backwards(cl, klass());
386 }
387
388 template <typename OopClosureType>
389 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
390 // In this assert, we cannot safely access the Klass* with compact headers.
391 assert(k == klass(), "wrong klass");
392 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
393 }
394
395 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
396 return obj == nullptr || obj->klass()->is_subtype_of(klass);
397 }
398
399 intptr_t oopDesc::identity_hash() {
400 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
401 // Note: The mark must be read into local variable to avoid concurrent updates.
402 markWord mrk = mark();
403 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
404 return mrk.hash();
405 } else if (mrk.is_marked()) {
406 return mrk.hash();
407 } else {
408 return slow_identity_hash();
409 }
410 }
411
412 // This checks fast simple case of whether the oop has_no_hash,
413 // to optimize JVMTI table lookup.
414 bool oopDesc::fast_no_hash_check() {
415 markWord mrk = mark_acquire();
416 assert(!mrk.is_marked(), "should never be marked");
417 return mrk.is_unlocked() && mrk.has_no_hash();
418 }
419
420 bool oopDesc::has_displaced_mark() const {
421 return mark().has_displaced_mark_helper();
422 }
423
424 markWord oopDesc::displaced_mark() const {
425 return mark().displaced_mark_helper();
426 }
427
428 void oopDesc::set_displaced_mark(markWord m) {
429 mark().set_displaced_mark_helper(m);
430 }
431
432 bool oopDesc::mark_must_be_preserved() const {
433 return mark_must_be_preserved(mark());
434 }
435
436 bool oopDesc::mark_must_be_preserved(markWord m) const {
437 return m.must_be_preserved();
438 }
439
440 #endif // SHARE_OOPS_OOP_INLINE_HPP
--- EOF ---