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.
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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/objectMonitor.inline.hpp"
42 #include "runtime/safepoint.hpp"
43 #include "runtime/synchronizer.hpp"
44 #include "utilities/align.hpp"
45 #include "utilities/debug.hpp"
46 #include "utilities/macros.hpp"
47 #include "utilities/globalDefinitions.hpp"
48
49 // Implementation of all inlined member functions defined in oop.hpp
50 // We need a separate file to avoid circular references
51
52 markWord oopDesc::mark() const {
53 return Atomic::load(&_mark);
54 }
55
56 markWord oopDesc::mark_acquire() const {
57 return Atomic::load_acquire(&_mark);
58 }
59
60 markWord* oopDesc::mark_addr() const {
61 return (markWord*) &_mark;
62 }
63
64 void oopDesc::set_mark(markWord m) {
65 Atomic::store(&_mark, m);
66 }
67
68 void oopDesc::set_mark(HeapWord* mem, markWord m) {
69 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
70 }
71
72 void oopDesc::release_set_mark(markWord m) {
73 Atomic::release_store(&_mark, m);
74 }
75
76 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
77 Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
78 }
79
80 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
81 return Atomic::cmpxchg(&_mark, old_mark, new_mark);
82 }
83
84 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
85 return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
86 }
87
88 markWord oopDesc::resolve_mark() const {
89 markWord hdr = mark();
90 if (hdr.has_monitor()) {
91 ObjectMonitor* monitor = hdr.monitor();
92 return monitor->header();
93 }
94 return hdr;
95 }
96
97 void oopDesc::init_mark() {
98 #ifdef _LP64
99 markWord header = resolve_mark();
100 assert(UseCompressedClassPointers, "expect compressed klass pointers");
101 header = markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value());
102 #else
103 markWord header = markWord::prototype();
104 #endif
105 set_mark(header);
106 }
107
108 Klass* oopDesc::klass() const {
109 #ifdef _LP64
110 assert(UseCompressedClassPointers, "only with compressed class pointers");
111 markWord header = resolve_mark();
112 return header.klass();
113 #else
114 return _klass;
115 #endif
116 }
117
118 Klass* oopDesc::klass_or_null() const {
119 #ifdef _LP64
120 assert(UseCompressedClassPointers, "only with compressed class pointers");
121 markWord header = resolve_mark();
122 return header.klass_or_null();
123 #else
124 return _klass;
125 #endif
126 }
127
128 Klass* oopDesc::klass_or_null_acquire() const {
129 #ifdef _LP64
130 assert(UseCompressedClassPointers, "only with compressed class pointers");
131 markWord header = mark_acquire();
132 if (header.has_monitor()) {
133 header = header.monitor()->header();
134 }
135 return header.klass_or_null();
136 #else
137 return Atomic::load_acquire(&_klass);
138 #endif
139 }
140
141 #ifndef _LP64
142 void oopDesc::set_klass(Klass* k) {
143 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
144 _klass = k;
145 }
146
147 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
148 assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
149 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
150 if (UseCompressedClassPointers) {
151 Atomic::release_store((narrowKlass*)raw_mem,
152 CompressedKlassPointers::encode_not_null(k));
153 } else {
154 Atomic::release_store((Klass**)raw_mem, k);
155 }
156 }
157 #endif
158
159 bool oopDesc::is_a(Klass* k) const {
160 return klass()->is_subtype_of(k);
161 }
162
163 size_t oopDesc::size() {
164 return size_given_klass(klass());
165 }
166
167 size_t oopDesc::size_given_klass(Klass* klass) {
168 int lh = klass->layout_helper();
169 size_t s;
170
171 // lh is now a value computed at class initialization that may hint
172 // at the size. For instances, this is positive and equal to the
173 // size. For arrays, this is negative and provides log2 of the
174 // array element size. For other oops, it is zero and thus requires
175 // a virtual call.
176 //
177 // We go to all this trouble because the size computation is at the
178 // heart of phase 2 of mark-compaction, and called for every object,
179 // alive or dead. So the speed here is equal in importance to the
180 // speed of allocation.
181
182 if (lh > Klass::_lh_neutral_value) {
183 if (!Klass::layout_helper_needs_slow_path(lh)) {
184 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
185 } else {
186 s = klass->oop_size(this);
187 }
188 } else if (lh <= Klass::_lh_neutral_value) {
189 // The most common case is instances; fall through if so.
190 if (lh < Klass::_lh_neutral_value) {
191 // Second most common case is arrays. We have to fetch the
192 // length of the array, shift (multiply) it appropriately,
193 // up to wordSize, add the header, and align to object size.
194 size_t size_in_bytes;
195 size_t array_length = (size_t) ((arrayOop)this)->length();
196 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
197 size_in_bytes += Klass::layout_helper_header_size(lh);
198
199 // This code could be simplified, but by keeping array_header_in_bytes
200 // in units of bytes and doing it this way we can round up just once,
201 // skipping the intermediate round to HeapWordSize.
202 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
203
204 assert(s == klass->oop_size(this) || size_might_change(), "wrong array object size");
205 } else {
206 // Must be zero, so bite the bullet and take the virtual call.
207 s = klass->oop_size(this);
208 }
209 }
210
211 assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
212 assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
213 return s;
214 }
215
216 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
217 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
218 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
219 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
220 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
221 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
222
223 template<typename T>
224 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
225
226 template <typename T>
227 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
228
229 template <DecoratorSet decorators>
230 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
231 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
232
233 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
234 template <DecoratorSet decorators>
235 inline void oopDesc::obj_field_put_access(int offset, oop value) { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
236
237 inline jbyte oopDesc::byte_field(int offset) const { return *field_addr<jbyte>(offset); }
238 inline void oopDesc::byte_field_put(int offset, jbyte value) { *field_addr<jbyte>(offset) = value; }
239
240 inline jchar oopDesc::char_field(int offset) const { return *field_addr<jchar>(offset); }
241 inline void oopDesc::char_field_put(int offset, jchar value) { *field_addr<jchar>(offset) = value; }
242
243 inline jboolean oopDesc::bool_field(int offset) const { return *field_addr<jboolean>(offset); }
244 inline void oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
245 inline jboolean oopDesc::bool_field_volatile(int offset) const { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
246 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
247 inline jshort oopDesc::short_field(int offset) const { return *field_addr<jshort>(offset); }
248 inline void oopDesc::short_field_put(int offset, jshort value) { *field_addr<jshort>(offset) = value; }
249
250 inline jint oopDesc::int_field(int offset) const { return *field_addr<jint>(offset); }
251 inline void oopDesc::int_field_put(int offset, jint value) { *field_addr<jint>(offset) = value; }
252
253 inline jlong oopDesc::long_field(int offset) const { return *field_addr<jlong>(offset); }
254 inline void oopDesc::long_field_put(int offset, jlong value) { *field_addr<jlong>(offset) = value; }
255
256 inline jfloat oopDesc::float_field(int offset) const { return *field_addr<jfloat>(offset); }
257 inline void oopDesc::float_field_put(int offset, jfloat value) { *field_addr<jfloat>(offset) = value; }
258
259 inline jdouble oopDesc::double_field(int offset) const { return *field_addr<jdouble>(offset); }
260 inline void oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
261
262 bool oopDesc::is_locked() const {
263 return mark().is_locked();
264 }
265
266 bool oopDesc::is_unlocked() const {
267 return mark().is_unlocked();
268 }
269
270 // Used only for markSweep, scavenging
271 bool oopDesc::is_gc_marked() const {
272 return mark().is_marked();
273 }
274
275 // Used by scavengers
276 bool oopDesc::is_forwarded() const {
277 // The extra heap check is needed since the obj might be locked, in which case the
278 // mark would point to a stack location and have the sentinel bit cleared
279 return mark().is_marked();
280 }
281
282 // Used by scavengers
283 void oopDesc::forward_to(oop p) {
284 verify_forwardee(p);
285 markWord m = markWord::encode_pointer_as_mark(p);
286 assert(forwardee(m) == p, "encoding must be reversable");
287 set_mark(m);
288 }
289
290 void oopDesc::forward_to_self() {
291 #ifdef _LP64
292 verify_forwardee(this);
293 markWord m = mark();
294 // If mark is displaced, we need to preserve the Klass* from real header.
295 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
296 if (m.has_displaced_mark_helper()) {
297 m = m.displaced_mark_helper();
298 }
299 m = m.set_self_forwarded();
300 assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
301 set_mark(m);
302 #else
303 forward_to(oop(this));
304 #endif
305 }
306
307 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
308 verify_forwardee(p);
309 markWord m = markWord::encode_pointer_as_mark(p);
310 assert(forwardee(m) == p, "encoding must be reversable");
311 markWord old_mark = cas_set_mark(m, compare, order);
312 if (old_mark == compare) {
313 return NULL;
314 } else {
315 return forwardee(old_mark);
316 }
317 }
318
319 oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
320 #ifdef _LP64
321 verify_forwardee(this);
322 markWord m = compare;
323 // If mark is displaced, we need to preserve the Klass* from real header.
324 assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
325 if (m.has_displaced_mark_helper()) {
326 m = m.displaced_mark_helper();
327 }
328 m = m.set_self_forwarded();
329 assert(forwardee(m) == cast_to_oop(this), "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 assert(old_mark.is_marked(), "must be marked here");
335 return forwardee(old_mark);
336 }
337 #else
338 return forward_to_atomic(oop(this), compare, order);
339 #endif
340 }
341
342 // Note that the forwardee is not the same thing as the displaced_mark.
343 // The forwardee is used when copying during scavenge and mark-sweep.
344 // It does need to clear the low two locking- and GC-related bits.
345 oop oopDesc::forwardee() const {
346 return forwardee(mark());
347 }
348
349 oop oopDesc::forwardee(markWord header) const {
350 assert(header.is_marked(), "must be forwarded");
351 #ifdef _LP64
352 if (header.self_forwarded()) {
353 return cast_to_oop(this);
354 } else
355 #endif
356 {
357 assert(header.is_marked(), "only decode when actually forwarded");
358 return cast_to_oop(header.decode_pointer());
359 }
360 }
361
362 // The following method needs to be MT safe.
363 uint oopDesc::age() const {
364 assert(!mark().is_marked(), "Attempt to read age from forwarded mark");
365 if (has_displaced_mark()) {
366 return displaced_mark().age();
367 } else {
368 return mark().age();
369 }
370 }
371
372 void oopDesc::incr_age() {
373 assert(!mark().is_marked(), "Attempt to increment age of forwarded mark");
374 if (has_displaced_mark()) {
375 set_displaced_mark(displaced_mark().incr_age());
376 } else {
377 set_mark(mark().incr_age());
378 }
379 }
380
381 template <typename OopClosureType>
382 void oopDesc::oop_iterate(OopClosureType* cl) {
383 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
384 }
385
386 template <typename OopClosureType>
387 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
388 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
389 }
390
391 template <typename OopClosureType>
392 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
393 Klass* k = klass();
394 size_t size = size_given_klass(k);
395 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
396 return size;
397 }
398
399 template <typename OopClosureType>
400 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
401 Klass* k = klass();
402 size_t size = size_given_klass(k);
403 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
404 return size;
405 }
406
407 template <typename OopClosureType>
408 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
409 oop_iterate_backwards(cl, klass());
410 }
411
412 template <typename OopClosureType>
413 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
414 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
415 }
416
417 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
418 return obj == NULL || obj->klass()->is_subtype_of(klass);
419 }
420
421 intptr_t oopDesc::identity_hash() {
422 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
423 // Note: The mark must be read into local variable to avoid concurrent updates.
424 markWord mrk = mark();
425 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
426 return mrk.hash();
427 } else if (mrk.is_marked()) {
428 return mrk.hash();
429 } else {
430 return slow_identity_hash();
431 }
432 }
433
434 // This checks fast simple case of whether the oop has_no_hash,
435 // to optimize JVMTI table lookup.
436 bool oopDesc::fast_no_hash_check() {
437 markWord mrk = mark_acquire();
438 assert(!mrk.is_marked(), "should never be marked");
439 return mrk.is_unlocked() && mrk.has_no_hash();
440 }
441
442 bool oopDesc::has_displaced_mark() const {
443 return mark().has_displaced_mark_helper();
444 }
445
446 markWord oopDesc::displaced_mark() const {
447 return mark().displaced_mark_helper();
448 }
449
450 void oopDesc::set_displaced_mark(markWord m) {
451 mark().set_displaced_mark_helper(m);
452 }
453
454 bool oopDesc::mark_must_be_preserved() const {
455 return mark_must_be_preserved(mark());
456 }
457
458 bool oopDesc::mark_must_be_preserved(markWord m) const {
459 return m.must_be_preserved(this);
460 }
461
462 #endif // SHARE_OOPS_OOP_INLINE_HPP