1 /*
2 * Copyright (c) 1997, 2021, 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/universe.hpp"
31 #include "oops/access.inline.hpp"
32 #include "oops/arrayKlass.hpp"
33 #include "oops/arrayOop.hpp"
34 #include "oops/compressedOops.inline.hpp"
35 #include "oops/markWord.inline.hpp"
36 #include "oops/oopsHierarchy.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/globals.hpp"
39 #include "runtime/objectMonitor.inline.hpp"
40 #include "utilities/align.hpp"
41 #include "utilities/debug.hpp"
42 #include "utilities/macros.hpp"
43 #include "utilities/globalDefinitions.hpp"
44
45 // Implementation of all inlined member functions defined in oop.hpp
46 // We need a separate file to avoid circular references
47
48 markWord oopDesc::mark() const {
49 uintptr_t v = HeapAccess<MO_RELAXED>::load_at(as_oop(), mark_offset_in_bytes());
50 return markWord(v);
51 }
52
53 markWord oopDesc::mark_acquire() const {
54 return Atomic::load_acquire(&_mark);
55 }
56 markWord* oopDesc::mark_addr() const {
57 return (markWord*) &_mark;
58 }
59
60 void oopDesc::set_mark(markWord m) {
61 HeapAccess<MO_RELAXED>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
62 }
63
64 void oopDesc::set_mark(HeapWord* mem, markWord m) {
65 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
66 }
67
68 void oopDesc::release_set_mark(markWord m) {
69 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
70 }
71
72 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
73 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
74 }
75
76 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
77 uintptr_t v = HeapAccess<>::atomic_cmpxchg_at(as_oop(), mark_offset_in_bytes(), old_mark.value(), new_mark.value());
78 return markWord(v);
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::resolve_mark() const {
86 assert(UseFastLocking, "Only safe with fast-locking");
87 markWord hdr = mark();
88 if (hdr.has_displaced_mark_helper()) {
89 hdr = hdr.displaced_mark_helper();
90 }
91 return hdr;
92 }
93
94 void oopDesc::init_mark() {
95 #ifdef _LP64
96 if (UseCompactObjectHeaders) {
97 markWord header = resolve_mark();
98 assert(UseCompressedClassPointers, "expect compressed klass pointers");
99 set_mark(markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value()));
100 } else
101 #endif
102 set_mark(markWord::prototype());
103 }
104
105 Klass* oopDesc::klass() const {
106 #ifdef _LP64
107 if (UseCompactObjectHeaders) {
108 assert(UseCompressedClassPointers, "only with compressed class pointers");
109 markWord header = resolve_mark();
110 return header.klass();
111 } else if (UseCompressedClassPointers) {
112 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
113 } else
114 #endif
115 return _metadata._klass;
116 }
117
118 Klass* oopDesc::klass_or_null() const {
119 #ifdef _LP64
120 if (UseCompactObjectHeaders) {
121 assert(UseCompressedClassPointers, "only with compressed class pointers");
122 markWord header = resolve_mark();
123 return header.klass_or_null();
124 } else if (UseCompressedClassPointers) {
125 return CompressedKlassPointers::decode(_metadata._compressed_klass);
126 } else
127 #endif
128 return _metadata._klass;
129 }
130
131 Klass* oopDesc::klass_or_null_acquire() const {
132 #ifdef _LP64
133 if (UseCompactObjectHeaders) {
134 assert(UseCompressedClassPointers, "only with compressed class pointers");
135 markWord header = mark_acquire();
136 if (header.has_monitor()) {
137 header = header.monitor()->header();
138 }
139 return header.klass_or_null();
140 } else if (UseCompressedClassPointers) {
141 narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
142 return CompressedKlassPointers::decode(nklass);
143 } else
144 #endif
145 return Atomic::load_acquire(&_metadata._klass);
146 }
147
148 void oopDesc::set_klass(Klass* k) {
149 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
150 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
151 if (UseCompressedClassPointers) {
152 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
153 } else {
154 _metadata._klass = k;
155 }
156 }
157
158 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
159 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
160 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
161 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
162 if (UseCompressedClassPointers) {
163 Atomic::release_store((narrowKlass*)raw_mem,
164 CompressedKlassPointers::encode_not_null(k));
165 } else {
166 Atomic::release_store((Klass**)raw_mem, k);
167 }
168 }
169
170 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
171 assert(!UseCompactObjectHeaders, "don't set Klass* gap with compact headers");
172 if (UseCompressedClassPointers) {
173 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
174 }
175 }
176
177 bool oopDesc::is_a(Klass* k) const {
178 return klass()->is_subtype_of(k);
179 }
180
181 int oopDesc::size() {
182 return size_given_klass(klass());
183 }
184
185 int oopDesc::size_given_klass(Klass* klass) {
186 int lh = klass->layout_helper();
187 int s;
188
189 // lh is now a value computed at class initialization that may hint
190 // at the size. For instances, this is positive and equal to the
191 // size. For arrays, this is negative and provides log2 of the
192 // array element size. For other oops, it is zero and thus requires
193 // a virtual call.
194 //
195 // We go to all this trouble because the size computation is at the
196 // heart of phase 2 of mark-compaction, and called for every object,
197 // alive or dead. So the speed here is equal in importance to the
198 // speed of allocation.
199
200 if (lh > Klass::_lh_neutral_value) {
201 if (!Klass::layout_helper_needs_slow_path(lh)) {
202 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
203 } else {
204 s = klass->oop_size(this);
205 }
206 } else if (lh <= Klass::_lh_neutral_value) {
207 // The most common case is instances; fall through if so.
208 if (lh < Klass::_lh_neutral_value) {
209 // Second most common case is arrays. We have to fetch the
210 // length of the array, shift (multiply) it appropriately,
211 // up to wordSize, add the header, and align to object size.
212 size_t size_in_bytes;
213 size_t array_length = (size_t) ((arrayOop)this)->length();
214 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
215 size_in_bytes += Klass::layout_helper_header_size(lh);
216
217 // This code could be simplified, but by keeping array_header_in_bytes
218 // in units of bytes and doing it this way we can round up just once,
219 // skipping the intermediate round to HeapWordSize.
220 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
221
222 // UseParallelGC and UseG1GC can change the length field
223 // of an "old copy" of an object array in the young gen so it indicates
224 // the grey portion of an already copied array. This will cause the first
225 // disjunct below to fail if the two comparands are computed across such
226 // a concurrent change.
227 assert((s == klass->oop_size(this)) ||
228 (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
229 "wrong array object size");
230 } else {
231 // Must be zero, so bite the bullet and take the virtual call.
232 s = klass->oop_size(this);
233 }
234 }
235
236 assert(s > 0, "Oop size must be greater than zero, not %d", s);
237 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
238 return s;
239 }
240
241 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
242 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
243 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
244 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
245
246 void* oopDesc::field_addr(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
247
248 template <class T>
249 T* oopDesc::obj_field_addr(int offset) const { return (T*) field_addr(offset); }
250
251 template <typename T>
252 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
253
254 template <DecoratorSet decorators>
255 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
256 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
257
258 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
259
260 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
261 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
262
263 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
264 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
265
266 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
267 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
268 inline jboolean oopDesc::bool_field_volatile(int offset) const { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); }
269 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); }
270 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
271 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
272
273 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
274 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
275 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
276
277 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
278 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
279
280 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
281 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
282
283 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
284 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
285
286 bool oopDesc::is_locked() const {
287 return mark().is_locked();
288 }
289
290 bool oopDesc::is_unlocked() const {
291 return mark().is_unlocked();
292 }
293
294 bool oopDesc::has_bias_pattern() const {
295 return mark().has_bias_pattern();
296 }
297
298 // Used only for markSweep, scavenging
299 bool oopDesc::is_gc_marked() const {
300 return mark().is_marked();
301 }
302
303 // Used by scavengers
304 bool oopDesc::is_forwarded() const {
305 // The extra heap check is needed since the obj might be locked, in which case the
306 // mark would point to a stack location and have the sentinel bit cleared
307 return mark().is_marked();
308 }
309
310 // Used by scavengers
311 void oopDesc::forward_to(oop p) {
312 verify_forwardee(p);
313 markWord m = markWord::encode_pointer_as_mark(p);
314 assert(forwardee(m) == p, "encoding must be reversable");
315 set_mark(m);
316 }
317
318 // Used by parallel scavengers
319 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) {
320 verify_forwardee(p);
321 markWord m = markWord::encode_pointer_as_mark(p);
322 assert(m.decode_pointer() == p, "encoding must be reversable");
323 return cas_set_mark(m, compare, order) == compare;
324 }
325
326 void oopDesc::forward_to_self() {
327 #ifdef _LP64
328 verify_forwardee(this);
329 markWord m = mark();
330 // If mark is displaced, we need to preserve the Klass* from real header.
331 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
332 if (m.has_displaced_mark_helper()) {
333 m = m.displaced_mark_helper();
334 }
335 m = m.set_self_forwarded();
336 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
337 set_mark(m);
338 #else
339 forward_to(oop(this));
340 #endif
341 }
342
343 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
344 verify_forwardee(p);
345 markWord m = markWord::encode_pointer_as_mark(p);
346 assert(forwardee(m) == p, "encoding must be reversable");
347 markWord old_mark = cas_set_mark(m, compare, order);
348 if (old_mark == compare) {
349 return NULL;
350 } else {
351 return forwardee(old_mark);
352 }
353 }
354
355 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
356 #ifdef _LP64
357 verify_forwardee(this);
358 markWord m = compare;
359 // If mark is displaced, we need to preserve the Klass* from real header.
360 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
361 if (m.has_displaced_mark_helper()) {
362 m = m.displaced_mark_helper();
363 }
364 m = m.set_self_forwarded();
365 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
366 markWord old_mark = cas_set_mark(m, compare, order);
367 if (old_mark == compare) {
368 return NULL;
369 } else {
370 assert(old_mark.is_marked(), "must be marked here");
371 return forwardee(old_mark);
372 }
373 #else
374 return forward_to_atomic(oop(this), compare, order);
375 #endif
376 }
377
378 // Note that the forwardee is not the same thing as the displaced_mark.
379 // The forwardee is used when copying during scavenge and mark-sweep.
380 // It does need to clear the low two locking- and GC-related bits.
381 oop oopDesc::forwardee() const {
382 return forwardee(mark());
383 }
384
385 oop oopDesc::forwardee(markWord header) const {
386 assert(header.is_marked(), "must be forwarded");
387 #ifdef _LP64
388 if (header.self_forwarded()) {
389 return cast_to_oop(this);
390 } else
391 #endif
392 {
393 assert(header.is_marked(), "only decode when actually forwarded");
394 return cast_to_oop(header.decode_pointer());
395 }
396 }
397
398 // The following method needs to be MT safe.
399 uint oopDesc::age() const {
400 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
401 if (has_displaced_mark()) {
402 return displaced_mark().age();
403 } else {
404 return mark().age();
405 }
406 }
407
408 void oopDesc::incr_age() {
409 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
410 if (has_displaced_mark()) {
411 set_displaced_mark(displaced_mark().incr_age());
412 } else {
413 set_mark(mark().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 int oopDesc::oop_iterate_size(OopClosureType* cl) {
429 Klass* k = klass();
430 int size = size_given_klass(k);
431 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
432 return size;
433 }
434
435 template <typename OopClosureType>
436 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
437 Klass* k = klass();
438 int 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 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
451 }
452
453 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
454 return obj == NULL || obj->klass()->is_subtype_of(klass);
455 }
456
457 intptr_t oopDesc::identity_hash() {
458 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
459 // Note: The mark must be read into local variable to avoid concurrent updates.
460 markWord mrk = mark();
461 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
462 return mrk.hash();
463 } else if (mrk.is_marked()) {
464 return mrk.hash();
465 } else {
466 return slow_identity_hash();
467 }
468 }
469
470 bool oopDesc::has_displaced_mark() const {
471 return mark().has_displaced_mark_helper();
472 }
473
474 markWord oopDesc::displaced_mark() const {
475 return mark().displaced_mark_helper();
476 }
477
478 void oopDesc::set_displaced_mark(markWord m) {
479 mark().set_displaced_mark_helper(m);
480 }
481
482 bool oopDesc::mark_must_be_preserved() const {
483 return mark_must_be_preserved(mark());
484 }
485
486 bool oopDesc::mark_must_be_preserved(markWord m) const {
487 return m.must_be_preserved(this);
488 }
489
490 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
491 return m.must_be_preserved_for_promotion_failure(this);
492 }
493
494 #endif // SHARE_OOPS_OOP_INLINE_HPP