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).
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,
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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/safepoint.hpp"
40 #include "runtime/synchronizer.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 #ifdef _LP64
83 markWord header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
84 assert(_metadata._compressed_klass == header.narrow_klass(), "klass must match: " PTR_FORMAT, header.value());
85 assert(UseCompressedClassPointers, "expect compressed klass pointers");
86 header = markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value());
87 #else
88 markWord header = markWord::prototype();
89 #endif
90 set_mark(header);
91 }
92
93 Klass* oopDesc::klass() const {
94 #ifdef _LP64
95 assert(UseCompressedClassPointers, "only with compressed class pointers");
96 markWord header = mark();
97 if (!header.is_neutral()) {
98 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
99 }
100 assert(_metadata._compressed_klass == header.narrow_klass(), "narrow klass must be equal, header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
101 Klass* klass = header.klass();
102 assert(klass == CompressedKlassPointers::decode_not_null(_metadata._compressed_klass), "klass must match: header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
103 return klass;
104 #else
105 return _metadata._klass;
106 #endif
107 }
108
109 Klass* oopDesc::klass_or_null() const {
110 #ifdef _LP64
111 assert(UseCompressedClassPointers, "only with compressed class pointers");
112 markWord header = mark();
113 if (!header.is_neutral()) {
114 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
115 }
116 assert(_metadata._compressed_klass == header.narrow_klass(), "narrow klass must be equal, header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
117 Klass* klass = header.klass_or_null();
118 assert(klass == CompressedKlassPointers::decode(_metadata._compressed_klass), "klass must match: header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
119 return klass;
120 #else
121 return _metadata._klass;
122 #endif
123 }
124
125 Klass* oopDesc::klass_or_null_acquire() const {
126 #ifdef _LP64
127 assert(UseCompressedClassPointers, "only with compressed class pointers");
128 markWord header = mark_acquire();
129 if (!header.is_neutral()) {
130 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
131 }
132 assert(_metadata._compressed_klass == header.narrow_klass(), "narrow klass must be equal, header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
133 Klass* klass = header.klass_or_null();
134 assert(klass == CompressedKlassPointers::decode(_metadata._compressed_klass), "klass must match: header: " INTPTR_FORMAT ", nklass: " INTPTR_FORMAT, header.value(), intptr_t(_metadata._compressed_klass));
135 return klass;
136 #else
137 return Atomic::load_acquire(&_metadata._klass);
138 #endif
139 }
140
141 void oopDesc::set_klass(Klass* k) {
142 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
143 if (UseCompressedClassPointers) {
144 _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
145 } else {
146 _metadata._klass = k;
147 }
148 }
149
150 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
151 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
152 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
153 if (UseCompressedClassPointers) {
154 Atomic::release_store((narrowKlass*)raw_mem,
155 CompressedKlassPointers::encode_not_null(k));
156 } else {
157 Atomic::release_store((Klass**)raw_mem, k);
158 }
159 }
160
161 int oopDesc::klass_gap() const {
162 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
163 }
164
165 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
166 if (UseCompressedClassPointers) {
167 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
168 }
169 }
170
171 void oopDesc::set_klass_gap(int v) {
172 set_klass_gap((HeapWord*)this, v);
173 }
174
175 bool oopDesc::is_a(Klass* k) const {
176 return klass()->is_subtype_of(k);
177 }
178
179 size_t oopDesc::size() {
180 return size_given_klass(klass());
181 }
182
183 size_t oopDesc::size_given_klass(Klass* klass) {
184 int lh = klass->layout_helper();
185 size_t s;
186
187 // lh is now a value computed at class initialization that may hint
188 // at the size. For instances, this is positive and equal to the
189 // size. For arrays, this is negative and provides log2 of the
190 // array element size. For other oops, it is zero and thus requires
191 // a virtual call.
192 //
193 // We go to all this trouble because the size computation is at the
194 // heart of phase 2 of mark-compaction, and called for every object,
195 // alive or dead. So the speed here is equal in importance to the
196 // speed of allocation.
197
198 if (lh > Klass::_lh_neutral_value) {
199 if (!Klass::layout_helper_needs_slow_path(lh)) {
200 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
201 } else {
202 s = klass->oop_size(this);
203 }
204 } else if (lh <= Klass::_lh_neutral_value) {
205 // The most common case is instances; fall through if so.
206 if (lh < Klass::_lh_neutral_value) {
207 // Second most common case is arrays. We have to fetch the
208 // length of the array, shift (multiply) it appropriately,
209 // up to wordSize, add the header, and align to object size.
210 size_t size_in_bytes;
211 size_t array_length = (size_t) ((arrayOop)this)->length();
212 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
213 size_in_bytes += Klass::layout_helper_header_size(lh);
214
215 // This code could be simplified, but by keeping array_header_in_bytes
216 // in units of bytes and doing it this way we can round up just once,
217 // skipping the intermediate round to HeapWordSize.
218 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
219
220 // UseParallelGC and UseG1GC can change the length field
221 // of an "old copy" of an object array in the young gen so it indicates
222 // the grey portion of an already copied array. This will cause the first
223 // disjunct below to fail if the two comparands are computed across such
224 // a concurrent change.
225 assert((s == klass->oop_size(this)) ||
226 (Universe::is_gc_active() && is_objArray() && is_forwarded() && (get_UseParallelGC() || get_UseG1GC())),
227 "wrong array object size");
228 } else {
229 // Must be zero, so bite the bullet and take the virtual call.
230 s = klass->oop_size(this);
231 }
232 }
233
234 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
235 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
236 return s;
237 }
238
239 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
240 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
241 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
242 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
243
244 template<typename T>
245 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
246
247 template <typename T>
248 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
249
250 template <DecoratorSet decorators>
251 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
252 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
253
254 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
255
256 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
257 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
258
259 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
260 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
261
262 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
263 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
264 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
265 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
266 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
267 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
268
269 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
270 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
271
272 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
273 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
274
275 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
276 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
277
278 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
279 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
280
281 bool oopDesc::is_locked() const {
282 return mark().is_locked();
283 }
284
285 bool oopDesc::is_unlocked() const {
286 return mark().is_unlocked();
287 }
288
289 // Used only for markSweep, scavenging
290 bool oopDesc::is_gc_marked() const {
291 return mark().is_marked();
292 }
293
294 // Used by scavengers
295 bool oopDesc::is_forwarded() const {
296 // The extra heap check is needed since the obj might be locked, in which case the
297 // mark would point to a stack location and have the sentinel bit cleared
298 return mark().is_marked();
299 }
300
301 // Used by scavengers
302 void oopDesc::forward_to(oop p) {
303 verify_forwardee(p);
304 markWord m = markWord::encode_pointer_as_mark(p);
305 assert(forwardee(m) == p, "encoding must be reversable");
306 set_mark(m);
307 }
308
309 void oopDesc::forward_to_self() {
310 #ifdef _LP64
311 verify_forwardee(this);
312 markWord m = mark();
313 // If mark is displaced, we need to preserve the Klass* from real header.
314 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
315 if (m.has_displaced_mark_helper()) {
316 m = m.displaced_mark_helper();
317 }
318 m = m.set_self_forwarded();
319 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
320 set_mark(m);
321 #else
322 forward_to(oop(this));
323 #endif
324 }
325
326 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
327 verify_forwardee(p);
328 markWord m = markWord::encode_pointer_as_mark(p);
329 assert(forwardee(m) == p, "encoding must be reversable");
330 markWord old_mark = cas_set_mark(m, compare, order);
331 if (old_mark == compare) {
332 return NULL;
333 } else {
334 return forwardee(old_mark);
335 }
336 }
337
338 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
339 #ifdef _LP64
340 verify_forwardee(this);
341 markWord m = compare;
342 // If mark is displaced, we need to preserve the Klass* from real header.
343 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
344 if (m.has_displaced_mark_helper()) {
345 m = m.displaced_mark_helper();
346 }
347 m = m.set_self_forwarded();
348 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
349 markWord old_mark = cas_set_mark(m, compare, order);
350 if (old_mark == compare) {
351 return NULL;
352 } else {
353 assert(old_mark.is_marked(), "must be marked here");
354 return forwardee(old_mark);
355 }
356 #else
357 return forward_to_atomic(oop(this), compare, order);
358 #endif
359 }
360
361 // Note that the forwardee is not the same thing as the displaced_mark.
362 // The forwardee is used when copying during scavenge and mark-sweep.
363 // It does need to clear the low two locking- and GC-related bits.
364 oop oopDesc::forwardee() const {
365 return forwardee(mark());
366 }
367
368 oop oopDesc::forwardee(markWord header) const {
369 assert(header.is_marked(), "must be forwarded");
370 #ifdef _LP64
371 if (header.self_forwarded()) {
372 return cast_to_oop(this);
373 } else
374 #endif
375 {
376 return cast_to_oop(header.decode_pointer());
377 }
378 }
379
380 // The following method needs to be MT safe.
381 uint oopDesc::age() const {
382 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
383 if (has_displaced_mark()) {
384 return displaced_mark().age();
385 } else {
386 return mark().age();
387 }
388 }
389
390 void oopDesc::incr_age() {
391 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
392 if (has_displaced_mark()) {
393 set_displaced_mark(displaced_mark().incr_age());
394 } else {
395 set_mark(mark().incr_age());
396 }
397 }
398
399 template <typename OopClosureType>
400 void oopDesc::oop_iterate(OopClosureType* cl) {
401 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
402 }
403
404 template <typename OopClosureType>
405 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
406 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
407 }
408
409 template <typename OopClosureType>
410 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
411 Klass* k = klass();
412 size_t size = size_given_klass(k);
413 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
414 return size;
415 }
416
417 template <typename OopClosureType>
418 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
419 Klass* k = klass();
420 size_t size = size_given_klass(k);
421 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
422 return size;
423 }
424
425 template <typename OopClosureType>
426 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
427 oop_iterate_backwards(cl, klass());
428 }
429
430 template <typename OopClosureType>
431 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
432 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
433 }
434
435 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
436 return obj == NULL || obj->klass()->is_subtype_of(klass);
437 }
438
439 intptr_t oopDesc::identity_hash() {
440 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
441 // Note: The mark must be read into local variable to avoid concurrent updates.
442 markWord mrk = mark();
443 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
444 return mrk.hash();
445 } else if (mrk.is_marked()) {
446 return mrk.hash();
447 } else {
448 return slow_identity_hash();
449 }
450 }
451
452 bool oopDesc::has_displaced_mark() const {
453 return mark().has_displaced_mark_helper();
454 }
455
456 markWord oopDesc::displaced_mark() const {
457 return mark().displaced_mark_helper();
458 }
459
460 void oopDesc::set_displaced_mark(markWord m) {
461 mark().set_displaced_mark_helper(m);
462 }
463
464 bool oopDesc::mark_must_be_preserved() const {
465 return mark_must_be_preserved(mark());
466 }
467
468 bool oopDesc::mark_must_be_preserved(markWord m) const {
469 return m.must_be_preserved(this);
470 }
471
472 #endif // SHARE_OOPS_OOP_INLINE_HPP