1 /*
2 * Copyright (c) 1997, 2024, 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 *
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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 *
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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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/compressedKlass.inline.hpp"
36 #include "oops/instanceKlass.hpp"
37 #include "oops/markWord.inline.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 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
74 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
78 return Atomic::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 Atomic::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 if (UseCompactObjectHeaders) {
95 set_mark(prototype_mark());
96 } else {
97 set_mark(markWord::prototype());
98 }
99 }
100
101 Klass* oopDesc::klass() const {
102 if (UseCompactObjectHeaders) {
103 return mark().klass();
104 } else if (UseCompressedClassPointers) {
105 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
106 } else {
107 return _metadata._klass;
108 }
109 }
110
111 Klass* oopDesc::klass_or_null() const {
112 if (UseCompactObjectHeaders) {
113 return mark().klass_or_null();
114 } else if (UseCompressedClassPointers) {
115 return CompressedKlassPointers::decode(_metadata._compressed_klass);
116 } else {
117 return _metadata._klass;
118 }
119 }
120
121 Klass* oopDesc::klass_or_null_acquire() const {
122 if (UseCompactObjectHeaders) {
123 return mark_acquire().klass();
124 } else if (UseCompressedClassPointers) {
125 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
126 return CompressedKlassPointers::decode(nklass);
127 } else {
128 return Atomic::load_acquire(&_metadata._klass);
129 }
130 }
131
132 Klass* oopDesc::klass_without_asserts() const {
133 if (UseCompactObjectHeaders) {
134 return mark().klass_without_asserts();
135 } else if (UseCompressedClassPointers) {
136 return CompressedKlassPointers::decode_without_asserts(_metadata._compressed_klass);
137 } else {
138 return _metadata._klass;
139 }
140 }
141
142 void oopDesc::set_klass(Klass* k) {
143 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
144 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
145 if (UseCompressedClassPointers) {
146 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
147 } else {
148 _metadata._klass = k;
149 }
150 }
151
152 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
153 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
154 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
155 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
156 if (UseCompressedClassPointers) {
157 Atomic::release_store((narrowKlass*)raw_mem,
158 CompressedKlassPointers::encode_not_null(k));
159 } else {
160 Atomic::release_store((Klass**)raw_mem, k);
161 }
162 }
163
164 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
165 assert(!UseCompactObjectHeaders, "don't set Klass* gap with compact headers");
166 if (UseCompressedClassPointers) {
167 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
168 }
169 }
170
171 bool oopDesc::is_a(Klass* k) const {
172 return klass()->is_subtype_of(k);
173 }
174
175 size_t oopDesc::size() {
176 return size_given_klass(klass());
177 }
178
179 size_t oopDesc::size_given_klass(Klass* klass) {
180 int lh = klass->layout_helper();
181 size_t s;
182
183 // lh is now a value computed at class initialization that may hint
184 // at the size. For instances, this is positive and equal to the
185 // size. For arrays, this is negative and provides log2 of the
186 // array element size. For other oops, it is zero and thus requires
187 // a virtual call.
188 //
189 // We go to all this trouble because the size computation is at the
190 // heart of phase 2 of mark-compaction, and called for every object,
191 // alive or dead. So the speed here is equal in importance to the
192 // speed of allocation.
193
194 if (lh > Klass::_lh_neutral_value) {
195 if (!Klass::layout_helper_needs_slow_path(lh)) {
196 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
197 } else {
198 s = klass->oop_size(this);
199 }
200 } else if (lh <= Klass::_lh_neutral_value) {
201 // The most common case is instances; fall through if so.
202 if (lh < Klass::_lh_neutral_value) {
203 // Second most common case is arrays. We have to fetch the
204 // length of the array, shift (multiply) it appropriately,
205 // up to wordSize, add the header, and align to object size.
206 size_t size_in_bytes;
207 size_t array_length = (size_t) ((arrayOop)this)->length();
208 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
209 size_in_bytes += Klass::layout_helper_header_size(lh);
210
211 // This code could be simplified, but by keeping array_header_in_bytes
212 // in units of bytes and doing it this way we can round up just once,
213 // skipping the intermediate round to HeapWordSize.
214 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
215
216 assert(s == klass->oop_size(this) || size_might_change(klass), "wrong array object size");
217 } else {
218 // Must be zero, so bite the bullet and take the virtual call.
219 s = klass->oop_size(this);
220 }
221 }
222
223 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
224 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
225 return s;
226 }
227
228 #ifdef _LP64
229 Klass* oopDesc::forward_safe_klass_impl(markWord m) const {
230 assert(UseCompactObjectHeaders, "Only get here with compact headers");
231 if (m.is_marked()) {
232 oop fwd = forwardee(m);
233 markWord m2 = fwd->mark();
234 assert(!m2.is_marked() || m2.self_forwarded(), "no double forwarding: this: " PTR_FORMAT " (" INTPTR_FORMAT "), fwd: " PTR_FORMAT " (" INTPTR_FORMAT ")", p2i(this), m.value(), p2i(fwd), m2.value());
235 m = m2;
236 }
237 return m.klass();
238 }
239 #endif
240
241 Klass* oopDesc::forward_safe_klass(markWord m) const {
242 #ifdef _LP64
243 if (UseCompactObjectHeaders) {
244 return forward_safe_klass_impl(m);
245 } else
246 #endif
247 {
248 return klass();
249 }
250 }
251
252 Klass* oopDesc::forward_safe_klass() const {
253 #ifdef _LP64
254 if (UseCompactObjectHeaders) {
255 return forward_safe_klass_impl(mark());
256 } else
257 #endif
258 {
259 return klass();
260 }
261 }
262
263 size_t oopDesc::forward_safe_size() {
264 return size_given_klass(forward_safe_klass());
265 }
266
267 void oopDesc::forward_safe_init_mark() {
268 if (UseCompactObjectHeaders) {
269 set_mark(forward_safe_klass()->prototype_header());
270 } else {
271 set_mark(markWord::prototype());
272 }
273 }
274
275 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
276 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
277 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
278 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
279 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
280 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
281
282 template<typename T>
283 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
284
285 template <typename T>
286 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
287
288 template <DecoratorSet decorators>
289 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
290 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
291
292 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
293 template <DecoratorSet decorators>
294 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
295
296 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
297 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
298
299 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
300 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
301
302 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
303 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
304 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
305 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
306 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
307 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
308
309 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
310 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
311
312 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
313 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
314
315 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
316 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
317
318 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
319 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
320
321 bool oopDesc::is_locked() const {
322 return mark().is_locked();
323 }
324
325 bool oopDesc::is_unlocked() const {
326 return mark().is_unlocked();
327 }
328
329 bool oopDesc::is_gc_marked() const {
330 return mark().is_marked();
331 }
332
333 // Used by scavengers
334 bool oopDesc::is_forwarded() const {
335 return mark().is_forwarded();
336 }
337
338 bool oopDesc::is_self_forwarded() const {
339 return mark().self_forwarded();
340 }
341
342 // Used by scavengers
343 void oopDesc::forward_to(oop p) {
344 markWord m = markWord::encode_pointer_as_mark(p);
345 assert(m.decode_pointer() == p, "encoding must be reversible");
346 set_mark(m);
347 }
348
349 void oopDesc::forward_to_self() {
350 set_mark(mark().set_self_forwarded());
351 }
352
353 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
354 markWord old_mark = cas_set_mark(new_mark, compare, order);
355 if (old_mark == compare) {
356 return nullptr;
357 } else {
358 assert(old_mark.is_forwarded(), "must be forwarded here");
359 return forwardee(old_mark);
360 }
361 }
362
363 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
364 markWord m = markWord::encode_pointer_as_mark(p);
365 assert(forwardee(m) == p, "encoding must be reversible");
366 return cas_set_forwardee(m, compare, order);
367 }
368
369 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
370 markWord new_mark = old_mark.set_self_forwarded();
371 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
372 return cas_set_forwardee(new_mark, old_mark, order);
373 }
374
375 oop oopDesc::forwardee(markWord mark) const {
376 assert(mark.is_forwarded(), "only decode when actually forwarded");
377 if (mark.self_forwarded()) {
378 return cast_to_oop(this);
379 } else {
380 return cast_to_oop(mark.decode_pointer());
381 }
382 }
383
384 // Note that the forwardee is not the same thing as the displaced_mark.
385 // The forwardee is used when copying during scavenge and mark-sweep.
386 // It does need to clear the low two locking- and GC-related bits.
387 oop oopDesc::forwardee() const {
388 assert(is_forwarded(), "only decode when actually forwarded");
389 return forwardee(mark());
390 }
391
392 void oopDesc::unset_self_forwarded() {
393 set_mark(mark().unset_self_forwarded());
394 }
395
396 // The following method needs to be MT safe.
397 uint oopDesc::age() const {
398 markWord m = mark();
399 assert(!m.is_marked(), "Attempt to read age from forwarded mark");
400 if (m.has_displaced_mark_helper()) {
401 return m.displaced_mark_helper().age();
402 } else {
403 return m.age();
404 }
405 }
406
407 void oopDesc::incr_age() {
408 markWord m = mark();
409 assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
410 if (m.has_displaced_mark_helper()) {
411 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
412 } else {
413 set_mark(m.incr_age());
414 }
415 }
416
417 template <typename OopClosureType>
418 void oopDesc::oop_iterate(OopClosureType* cl) {
419 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
420 }
421
422 template <typename OopClosureType>
423 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
424 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
425 }
426
427 template <typename OopClosureType>
428 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
429 Klass* k = klass();
430 size_t size = size_given_klass(k);
431 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
432 return size;
433 }
434
435 template <typename OopClosureType>
436 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
437 Klass* k = klass();
438 size_t size = size_given_klass(k);
439 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
440 return size;
441 }
442
443 template <typename OopClosureType>
444 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
445 oop_iterate_backwards(cl, klass());
446 }
447
448 template <typename OopClosureType>
449 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
450 // In this assert, we cannot safely access the Klass* with compact headers.
451 assert(UseCompactObjectHeaders || k == klass(), "wrong klass");
452 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
453 }
454
455 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
456 return obj == nullptr || obj->klass()->is_subtype_of(klass);
457 }
458
459 intptr_t oopDesc::identity_hash() {
460 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
461 // Note: The mark must be read into local variable to avoid concurrent updates.
462 markWord mrk = mark();
463 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
464 return mrk.hash();
465 } else if (mrk.is_marked()) {
466 return mrk.hash();
467 } else {
468 return slow_identity_hash();
469 }
470 }
471
472 // This checks fast simple case of whether the oop has_no_hash,
473 // to optimize JVMTI table lookup.
474 bool oopDesc::fast_no_hash_check() {
475 markWord mrk = mark_acquire();
476 assert(!mrk.is_marked(), "should never be marked");
477 return mrk.is_unlocked() && mrk.has_no_hash();
478 }
479
480 bool oopDesc::has_displaced_mark() const {
481 return mark().has_displaced_mark_helper();
482 }
483
484 markWord oopDesc::displaced_mark() const {
485 return mark().displaced_mark_helper();
486 }
487
488 void oopDesc::set_displaced_mark(markWord m) {
489 mark().set_displaced_mark_helper(m);
490 }
491
492 bool oopDesc::mark_must_be_preserved() const {
493 return mark_must_be_preserved(mark());
494 }
495
496 bool oopDesc::mark_must_be_preserved(markWord m) const {
497 return m.must_be_preserved(this);
498 }
499
500 #endif // SHARE_OOPS_OOP_INLINE_HPP