1 /*
2 * Copyright (c) 1997, 2022, 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
6 * under the terms of the GNU General Public License version 2 only, as
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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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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/compressedKlass.inline.hpp"
35 #include "oops/compressedOops.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 "runtime/safepoint.hpp"
42 #include "runtime/synchronizer.hpp"
43 #include "utilities/align.hpp"
44 #include "utilities/debug.hpp"
45 #include "utilities/macros.hpp"
46 #include "utilities/globalDefinitions.hpp"
47
48 // Implementation of all inlined member functions defined in oop.hpp
49 // We need a separate file to avoid circular references
50
51 markWord oopDesc::mark() const {
52 return Atomic::load(&_mark);
53 }
54
55 markWord oopDesc::mark_acquire() const {
56 return Atomic::load_acquire(&_mark);
57 }
58
59 markWord* oopDesc::mark_addr() const {
60 return (markWord*) &_mark;
61 }
62
63 void oopDesc::set_mark(markWord m) {
64 Atomic::store(&_mark, m);
65 }
66
67 void oopDesc::set_mark(HeapWord* mem, markWord m) {
68 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
69 }
70
71 void oopDesc::release_set_mark(markWord m) {
72 Atomic::release_store(&_mark, m);
73 }
74
75 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
76 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
77 }
78
79 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
80 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
81 }
82
83 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
84 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
85 }
86
87 void oopDesc::init_mark() {
88 #ifdef _LP64
89 markWord header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
90 assert(UseCompressedClassPointers, "expect compressed klass pointers");
91 header = markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value());
92 #else
93 markWord header = markWord::prototype();
94 #endif
95 set_mark(header);
96 }
97
98 Klass* oopDesc::klass() const {
99 #ifdef _LP64
100 assert(UseCompressedClassPointers, "only with compressed class pointers");
101 markWord header = mark();
102 if (!header.is_neutral()) {
103 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
104 }
105 return header.klass();
106 #else
107 return _klass;
108 #endif
109 }
110
111 Klass* oopDesc::klass_or_null() const {
112 #ifdef _LP64
113 assert(UseCompressedClassPointers, "only with compressed class pointers");
114 markWord header = mark();
115 if (!header.is_neutral()) {
116 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
117 }
118 return header.klass_or_null();
119 #else
120 return _klass;
121 #endif
122 }
123
124 Klass* oopDesc::klass_or_null_acquire() const {
125 #ifdef _LP64
126 assert(UseCompressedClassPointers, "only with compressed class pointers");
127 markWord header = mark_acquire();
128 if (!header.is_neutral()) {
129 header = ObjectSynchronizer::stable_mark(cast_to_oop(this));
130 }
131 return header.klass_or_null();
132 #else
133 return Atomic::load_acquire(&_klass);
134 #endif
135 }
136
137 #ifndef _LP64
138 void oopDesc::set_klass(Klass* k) {
139 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
140 _klass = k;
141 }
142
143 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
144 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
145 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
146 if (UseCompressedClassPointers) {
147 Atomic::release_store((narrowKlass*)raw_mem,
148 CompressedKlassPointers::encode_not_null(k));
149 } else {
150 Atomic::release_store((Klass**)raw_mem, k);
151 }
152 }
153 #endif
154
155 bool oopDesc::is_a(Klass* k) const {
156 return klass()->is_subtype_of(k);
157 }
158
159 size_t oopDesc::size() {
160 return size_given_klass(klass());
161 }
162
163 size_t oopDesc::size_given_klass(Klass* klass) {
164 int lh = klass->layout_helper();
165 size_t s;
166
167 // lh is now a value computed at class initialization that may hint
168 // at the size. For instances, this is positive and equal to the
169 // size. For arrays, this is negative and provides log2 of the
170 // array element size. For other oops, it is zero and thus requires
171 // a virtual call.
172 //
173 // We go to all this trouble because the size computation is at the
174 // heart of phase 2 of mark-compaction, and called for every object,
175 // alive or dead. So the speed here is equal in importance to the
176 // speed of allocation.
177
178 if (lh > Klass::_lh_neutral_value) {
179 if (!Klass::layout_helper_needs_slow_path(lh)) {
180 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
181 } else {
182 s = klass->oop_size(this);
183 }
184 } else if (lh <= Klass::_lh_neutral_value) {
185 // The most common case is instances; fall through if so.
186 if (lh < Klass::_lh_neutral_value) {
187 // Second most common case is arrays. We have to fetch the
188 // length of the array, shift (multiply) it appropriately,
189 // up to wordSize, add the header, and align to object size.
190 size_t size_in_bytes;
191 size_t array_length = (size_t) ((arrayOop)this)->length();
192 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
193 size_in_bytes += Klass::layout_helper_header_size(lh);
194
195 // This code could be simplified, but by keeping array_header_in_bytes
196 // in units of bytes and doing it this way we can round up just once,
197 // skipping the intermediate round to HeapWordSize.
198 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
199
200 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
201 } else {
202 // Must be zero, so bite the bullet and take the virtual call.
203 s = klass->oop_size(this);
204 }
205 }
206
207 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
208 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
209 return s;
210 }
211
212 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
213 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
214 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
215 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
216 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
217 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
218
219 template<typename T>
220 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
221
222 template <typename T>
223 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
224
225 template <DecoratorSet decorators>
226 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
227 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
228
229 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::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
247 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
248 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
249
250 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
251 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
252
253 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
254 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
255
256 bool oopDesc::is_locked() const {
257 return mark().is_locked();
258 }
259
260 bool oopDesc::is_unlocked() const {
261 return mark().is_unlocked();
262 }
263
264 // Used only for markSweep, scavenging
265 bool oopDesc::is_gc_marked() const {
266 return mark().is_marked();
267 }
268
269 // Used by scavengers
270 bool oopDesc::is_forwarded() const {
271 // The extra heap check is needed since the obj might be locked, in which case the
272 // mark would point to a stack location and have the sentinel bit cleared
273 return mark().is_marked();
274 }
275
276 // Used by scavengers
277 void oopDesc::forward_to(oop p) {
278 verify_forwardee(p);
279 markWord m = markWord::encode_pointer_as_mark(p);
280 assert(forwardee(m) == p, "encoding must be reversable");
281 set_mark(m);
282 }
283
284 void oopDesc::forward_to_self() {
285 #ifdef _LP64
286 verify_forwardee(this);
287 markWord m = mark();
288 // If mark is displaced, we need to preserve the Klass* from real header.
289 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
290 if (m.has_displaced_mark_helper()) {
291 m = m.displaced_mark_helper();
292 }
293 m = m.set_self_forwarded();
294 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
295 set_mark(m);
296 #else
297 forward_to(oop(this));
298 #endif
299 }
300
301 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
302 verify_forwardee(p);
303 markWord m = markWord::encode_pointer_as_mark(p);
304 assert(forwardee(m) == p, "encoding must be reversable");
305 markWord old_mark = cas_set_mark(m, compare, order);
306 if (old_mark == compare) {
307 return NULL;
308 } else {
309 return forwardee(old_mark);
310 }
311 }
312
313 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
314 #ifdef _LP64
315 verify_forwardee(this);
316 markWord m = compare;
317 // If mark is displaced, we need to preserve the Klass* from real header.
318 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
319 if (m.has_displaced_mark_helper()) {
320 m = m.displaced_mark_helper();
321 }
322 m = m.set_self_forwarded();
323 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
324 markWord old_mark = cas_set_mark(m, compare, order);
325 if (old_mark == compare) {
326 return NULL;
327 } else {
328 assert(old_mark.is_marked(), "must be marked here");
329 return forwardee(old_mark);
330 }
331 #else
332 return forward_to_atomic(oop(this), compare, order);
333 #endif
334 }
335
336 // Note that the forwardee is not the same thing as the displaced_mark.
337 // The forwardee is used when copying during scavenge and mark-sweep.
338 // It does need to clear the low two locking- and GC-related bits.
339 oop oopDesc::forwardee() const {
340 return forwardee(mark());
341 }
342
343 oop oopDesc::forwardee(markWord header) const {
344 assert(header.is_marked(), "must be forwarded");
345 #ifdef _LP64
346 if (header.self_forwarded()) {
347 return cast_to_oop(this);
348 } else
349 #endif
350 {
351 assert(header.is_marked(), "only decode when actually forwarded");
352 return cast_to_oop(header.decode_pointer());
353 }
354 }
355
356 // The following method needs to be MT safe.
357 uint oopDesc::age() const {
358 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
359 if (has_displaced_mark()) {
360 return displaced_mark().age();
361 } else {
362 return mark().age();
363 }
364 }
365
366 void oopDesc::incr_age() {
367 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
368 if (has_displaced_mark()) {
369 set_displaced_mark(displaced_mark().incr_age());
370 } else {
371 set_mark(mark().incr_age());
372 }
373 }
374
375 template <typename OopClosureType>
376 void oopDesc::oop_iterate(OopClosureType* cl) {
377 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
378 }
379
380 template <typename OopClosureType>
381 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
382 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
383 }
384
385 template <typename OopClosureType>
386 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
387 Klass* k = klass();
388 size_t size = size_given_klass(k);
389 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
390 return size;
391 }
392
393 template <typename OopClosureType>
394 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
395 Klass* k = klass();
396 size_t size = size_given_klass(k);
397 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
398 return size;
399 }
400
401 template <typename OopClosureType>
402 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
403 oop_iterate_backwards(cl, klass());
404 }
405
406 template <typename OopClosureType>
407 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
408 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
409 }
410
411 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
412 return obj == NULL || obj->klass()->is_subtype_of(klass);
413 }
414
415 intptr_t oopDesc::identity_hash() {
416 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
417 // Note: The mark must be read into local variable to avoid concurrent updates.
418 markWord mrk = mark();
419 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
420 return mrk.hash();
421 } else if (mrk.is_marked()) {
422 return mrk.hash();
423 } else {
424 return slow_identity_hash();
425 }
426 }
427
428 bool oopDesc::has_displaced_mark() const {
429 return mark().has_displaced_mark_helper();
430 }
431
432 markWord oopDesc::displaced_mark() const {
433 return mark().displaced_mark_helper();
434 }
435
436 void oopDesc::set_displaced_mark(markWord m) {
437 mark().set_displaced_mark_helper(m);
438 }
439
440 bool oopDesc::mark_must_be_preserved() const {
441 return mark_must_be_preserved(mark());
442 }
443
444 bool oopDesc::mark_must_be_preserved(markWord m) const {
445 return m.must_be_preserved(this);
446 }
447
448 #endif // SHARE_OOPS_OOP_INLINE_HPP