1 /*
2 * Copyright (c) 1997, 2019, 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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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 "gc/shared/collectedHeap.hpp"
29 #include "oops/access.inline.hpp"
30 #include "oops/arrayKlass.hpp"
31 #include "oops/arrayOop.hpp"
32 #include "oops/compressedOops.inline.hpp"
33 #include "oops/klass.inline.hpp"
34 #include "oops/markOop.inline.hpp"
35 #include "oops/oop.hpp"
36 #include "runtime/atomic.hpp"
37 #include "runtime/orderAccess.hpp"
38 #include "runtime/os.hpp"
39 #include "utilities/align.hpp"
40 #include "utilities/macros.hpp"
41
42 // Implementation of all inlined member functions defined in oop.hpp
43 // We need a separate file to avoid circular references
44
45 markOop oopDesc::mark() const {
46 return HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes());
47 }
48
49 markOop oopDesc::mark_raw() const {
50 return _mark;
51 }
52
53 markOop* oopDesc::mark_addr_raw() const {
54 return (markOop*) &_mark;
55 }
56
57 void oopDesc::set_mark(volatile markOop m) {
58 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m);
59 }
60
61 void oopDesc::set_mark_raw(volatile markOop m) {
62 _mark = m;
63 }
64
65 void oopDesc::set_mark_raw(HeapWord* mem, markOop m) {
66 *(markOop*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(markOop m) {
70 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
71 }
72
73 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
74 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark);
75 }
76
77 markOop oopDesc::cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order) {
78 return Atomic::cmpxchg(new_mark, &_mark, old_mark, order);
79 }
80
81 void oopDesc::init_mark() {
82 set_mark(markOopDesc::prototype_for_object(this));
83 }
84
85 void oopDesc::init_mark_raw() {
86 set_mark_raw(markOopDesc::prototype_for_object(this));
87 }
88
89 narrowKlass oopDesc::compressed_klass_mask() { return ((narrowKlass) 1 << narrow_storage_props_shift) - 1; }
90 uintptr_t oopDesc::klass_mask() { return ((uintptr_t) 1 << wide_storage_props_shift) - 1; }
91
92 narrowKlass oopDesc::compressed_klass_masked(narrowKlass raw) { return raw & compressed_klass_mask(); }
93 Klass* oopDesc::klass_masked(uintptr_t raw) { return reinterpret_cast<Klass*>(raw & klass_mask()); }
94
95
96 Klass* oopDesc::klass() const {
97 if (UseCompressedClassPointers) {
98 return Klass::decode_klass_not_null(compressed_klass_masked(_metadata._compressed_klass));
99 } else {
100 return klass_masked(_metadata._wide_storage_props);
101 }
102 }
103
104 Klass* oopDesc::klass_or_null() const volatile {
105 if (UseCompressedClassPointers) {
106 return Klass::decode_klass(compressed_klass_masked(_metadata._compressed_klass));
107 } else {
108 return klass_masked(_metadata._wide_storage_props);
109 }
110 }
111
112 Klass* oopDesc::klass_or_null_acquire() const volatile {
113 if (UseCompressedClassPointers) {
114 // Workaround for non-const load_acquire parameter.
115 const volatile narrowKlass* addr = &_metadata._compressed_klass;
116 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
117 return Klass::decode_klass(compressed_klass_masked(OrderAccess::load_acquire(xaddr)));
118 } else {
119 return klass_masked(OrderAccess::load_acquire(&_metadata._wide_storage_props));
120 }
121 }
122
123 Klass** oopDesc::klass_addr(HeapWord* mem) {
124 // Only used internally and with CMS and will not work with
125 // UseCompressedOops
126 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
127 ByteSize offset = byte_offset_of(oopDesc, _metadata._klass);
128 return (Klass**) (((char*)mem) + in_bytes(offset));
129 }
130
131 uintptr_t* oopDesc::wide_metadata_addr(HeapWord* mem) {
132 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
133 ByteSize offset = byte_offset_of(oopDesc, _metadata._wide_storage_props);
134 return (uintptr_t*) (((char*)mem) + in_bytes(offset));
135 }
136
137 narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) {
138 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
139 ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass);
140 return (narrowKlass*) (((char*)mem) + in_bytes(offset));
141 }
142
143 Klass** oopDesc::klass_addr() {
144 return klass_addr((HeapWord*)this);
145 }
146
147 narrowKlass* oopDesc::compressed_klass_addr() {
148 return compressed_klass_addr((HeapWord*)this);
149 }
150
151 #define CHECK_SET_KLASS(k) \
152 do { \
153 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
154 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
155 assert(((reinterpret_cast<uintptr_t>(k) & (~ oopDesc::klass_mask())) == 0), \
156 "No room for storage props "); \
157 } while (0)
158
159 void oopDesc::set_klass(Klass* k) {
160 CHECK_SET_KLASS(k);
161 if (UseCompressedClassPointers) {
162 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
163 } else {
164 *klass_addr() = k;
165 }
166 }
167
168 void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) {
169 CHECK_SET_KLASS(klass);
170 if (UseCompressedClassPointers) {
171 OrderAccess::release_store(compressed_klass_addr(mem),
172 Klass::encode_klass_not_null(klass));
173 } else {
174 OrderAccess::release_store(klass_addr(mem), klass);
175 }
176 assert(((oopDesc*)mem)->klass() == klass, "failed oopDesc::klass() encode/decode");
177 }
178
179 void oopDesc::set_metadata(ArrayStorageProperties storage_props, Klass* klass) {
180 CHECK_SET_KLASS(klass);
181 if (UseCompressedClassPointers) {
182 *compressed_klass_addr() = (Klass::encode_klass_not_null(klass) | storage_props.encode<narrowKlass>(narrow_storage_props_shift));
183 } else {
184 *wide_metadata_addr((HeapWord*)this) = (reinterpret_cast<uintptr_t>(klass) | storage_props.encode<uintptr_t>(wide_storage_props_shift));
185 }
186 }
187
188 void oopDesc::release_set_metadata(HeapWord* mem, ArrayStorageProperties storage_props, Klass* klass) {
189 CHECK_SET_KLASS(klass);
190 if (UseCompressedClassPointers) {
191 OrderAccess::release_store(oopDesc::compressed_klass_addr(mem),
192 Klass::encode_klass_not_null(klass) | storage_props.encode<narrowKlass>(narrow_storage_props_shift));
193 } else {
194 OrderAccess::release_store(oopDesc::wide_metadata_addr(mem),
195 (reinterpret_cast<uintptr_t>(klass) | storage_props.encode<uintptr_t>(wide_storage_props_shift)));
196 }
197 }
198 #undef CHECK_SET_KLASS
199
200
201 ArrayStorageProperties oopDesc::array_storage_properties() const {
202 if (UseCompressedClassPointers) {
203 return ArrayStorageProperties(_metadata._narrow_storage_props >> narrow_storage_props_shift);
204 } else {
205 return ArrayStorageProperties(_metadata._wide_storage_props >> wide_storage_props_shift);
206 }
207 }
208
209
210 int oopDesc::klass_gap() const {
211 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
212 }
213
214 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
215 if (UseCompressedClassPointers) {
216 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
217 }
218 }
219
220 void oopDesc::set_klass_gap(int v) {
221 set_klass_gap((HeapWord*)this, v);
222 }
223
224 void oopDesc::set_klass_to_list_ptr(oop k) {
225 // This is only to be used during GC, for from-space objects, so no
226 // barrier is needed.
227 if (UseCompressedClassPointers) {
228 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
229 } else {
230 _metadata._klass = (Klass*)(address)k;
231 }
232 }
233
234 oop oopDesc::list_ptr_from_klass() {
235 // This is only to be used during GC, for from-space objects.
236 if (UseCompressedClassPointers) {
237 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
238 } else {
239 // Special case for GC
240 return (oop)(address)_metadata._klass;
241 }
242 }
243
244 bool oopDesc::is_a(Klass* k) const {
245 return klass()->is_subtype_of(k);
246 }
247
248 int oopDesc::size() {
249 return size_given_klass(klass());
250 }
251
252 int oopDesc::size_given_klass(Klass* klass) {
253 int lh = klass->layout_helper();
254 int s;
255
256 // lh is now a value computed at class initialization that may hint
257 // at the size. For instances, this is positive and equal to the
258 // size. For arrays, this is negative and provides log2 of the
259 // array element size. For other oops, it is zero and thus requires
260 // a virtual call.
261 //
262 // We go to all this trouble because the size computation is at the
263 // heart of phase 2 of mark-compaction, and called for every object,
264 // alive or dead. So the speed here is equal in importance to the
265 // speed of allocation.
266
267 if (lh > Klass::_lh_neutral_value) {
268 if (!Klass::layout_helper_needs_slow_path(lh)) {
269 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
270 } else {
271 s = klass->oop_size(this);
272 }
273 } else if (lh <= Klass::_lh_neutral_value) {
274 // The most common case is instances; fall through if so.
275 if (lh < Klass::_lh_neutral_value) {
276 // Second most common case is arrays. We have to fetch the
277 // length of the array, shift (multiply) it appropriately,
278 // up to wordSize, add the header, and align to object size.
279 size_t size_in_bytes;
280 size_t array_length = (size_t) ((arrayOop)this)->length();
281 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
282 size_in_bytes += Klass::layout_helper_header_size(lh);
283
284 // This code could be simplified, but by keeping array_header_in_bytes
285 // in units of bytes and doing it this way we can round up just once,
286 // skipping the intermediate round to HeapWordSize.
287 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
288
289 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
290 // of an "old copy" of an object array in the young gen so it indicates
291 // the grey portion of an already copied array. This will cause the first
292 // disjunct below to fail if the two comparands are computed across such
293 // a concurrent change.
294 // ParNew also runs with promotion labs (which look like int
295 // filler arrays) which are subject to changing their declared size
296 // when finally retiring a PLAB; this also can cause the first disjunct
297 // to fail for another worker thread that is concurrently walking the block
298 // offset table. Both these invariant failures are benign for their
299 // current uses; we relax the assertion checking to cover these two cases below:
300 // is_objArray() && is_forwarded() // covers first scenario above
301 // || is_typeArray() // covers second scenario above
302 // If and when UseParallelGC uses the same obj array oop stealing/chunking
303 // technique, we will need to suitably modify the assertion.
304 assert((s == klass->oop_size(this)) ||
305 (Universe::heap()->is_gc_active() &&
306 ((is_typeArray() && UseConcMarkSweepGC) ||
307 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
308 "wrong array object size");
309 } else {
310 // Must be zero, so bite the bullet and take the virtual call.
311 s = klass->oop_size(this);
312 }
313 }
314
315 assert(s > 0, "Oop size must be greater than zero, not %d", s);
316 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
317 return s;
318 }
319
320 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
321 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
322 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
323 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
324 bool oopDesc::is_value() const { return klass()->is_value(); }
325 bool oopDesc::is_valueArray() const { return klass()->is_valueArray_klass(); }
326
327 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
328 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
329
330 template <class T>
331 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
332
333 template <typename T>
334 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
335
336 template <DecoratorSet decorators>
337 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
338 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
339
340 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
341
342 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
343 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
344
345 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
346 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
347
348 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
349 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
350
351 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
352 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
353
354 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
355 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
356 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
357
358 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
359 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
360
361 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
362 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
363
364 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
365 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
366
367 bool oopDesc::is_locked() const {
368 return mark()->is_locked();
369 }
370
371 bool oopDesc::is_unlocked() const {
372 return mark()->is_unlocked();
373 }
374
375 bool oopDesc::has_bias_pattern() const {
376 return mark()->has_bias_pattern();
377 }
378
379
380 bool oopDesc::has_bias_pattern_raw() const {
381 return mark_raw()->has_bias_pattern();
382 }
383
384 // Used only for markSweep, scavenging
385 bool oopDesc::is_gc_marked() const {
386 return mark_raw()->is_marked();
387 }
388
389 // Used by scavengers
390 bool oopDesc::is_forwarded() const {
391 // The extra heap check is needed since the obj might be locked, in which case the
392 // mark would point to a stack location and have the sentinel bit cleared
393 return mark_raw()->is_marked();
394 }
395
396 // Used by scavengers
397 void oopDesc::forward_to(oop p) {
398 assert(check_obj_alignment(p),
399 "forwarding to something not aligned");
400 assert(Universe::heap()->is_in_reserved(p),
401 "forwarding to something not in heap");
402 assert(!is_archived_object(oop(this)) &&
403 !is_archived_object(p),
404 "forwarding archive object");
405 markOop m = markOopDesc::encode_pointer_as_mark(p);
406 assert(m->decode_pointer() == p, "encoding must be reversable");
407 set_mark_raw(m);
408 }
409
410 // Used by parallel scavengers
411 bool oopDesc::cas_forward_to(oop p, markOop compare, atomic_memory_order order) {
412 assert(check_obj_alignment(p),
413 "forwarding to something not aligned");
414 assert(Universe::heap()->is_in_reserved(p),
415 "forwarding to something not in heap");
416 markOop m = markOopDesc::encode_pointer_as_mark(p);
417 assert(m->decode_pointer() == p, "encoding must be reversable");
418 return cas_set_mark_raw(m, compare, order) == compare;
419 }
420
421 oop oopDesc::forward_to_atomic(oop p, markOop compare, atomic_memory_order order) {
422 // CMS forwards some non-heap value into the mark oop to reserve oops during
423 // promotion, so the next two asserts do not hold.
424 assert(UseConcMarkSweepGC || check_obj_alignment(p),
425 "forwarding to something not aligned");
426 assert(UseConcMarkSweepGC || Universe::heap()->is_in_reserved(p),
427 "forwarding to something not in heap");
428 markOop m = markOopDesc::encode_pointer_as_mark(p);
429 assert(m->decode_pointer() == p, "encoding must be reversable");
430 markOop old_mark = cas_set_mark_raw(m, compare, order);
431 if (old_mark == compare) {
432 return NULL;
433 } else {
434 return (oop)old_mark->decode_pointer();
435 }
436 }
437
438 // Note that the forwardee is not the same thing as the displaced_mark.
439 // The forwardee is used when copying during scavenge and mark-sweep.
440 // It does need to clear the low two locking- and GC-related bits.
441 oop oopDesc::forwardee() const {
442 return (oop) mark_raw()->decode_pointer();
443 }
444
445 // Note that the forwardee is not the same thing as the displaced_mark.
446 // The forwardee is used when copying during scavenge and mark-sweep.
447 // It does need to clear the low two locking- and GC-related bits.
448 oop oopDesc::forwardee_acquire() const {
449 markOop m = OrderAccess::load_acquire(&_mark);
450 return (oop) m->decode_pointer();
451 }
452
453 // The following method needs to be MT safe.
454 uint oopDesc::age() const {
455 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
456 if (has_displaced_mark_raw()) {
457 return displaced_mark_raw()->age();
458 } else {
459 return mark_raw()->age();
460 }
461 }
462
463 void oopDesc::incr_age() {
464 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
465 if (has_displaced_mark_raw()) {
466 set_displaced_mark_raw(displaced_mark_raw()->incr_age());
467 } else {
468 set_mark_raw(mark_raw()->incr_age());
469 }
470 }
471
472 template <typename OopClosureType>
473 void oopDesc::oop_iterate(OopClosureType* cl) {
474 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
475 }
476
477 template <typename OopClosureType>
478 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
479 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
480 }
481
482 template <typename OopClosureType>
483 int oopDesc::oop_iterate_size(OopClosureType* cl) {
484 Klass* k = klass();
485 int size = size_given_klass(k);
486 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
487 return size;
488 }
489
490 template <typename OopClosureType>
491 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
492 Klass* k = klass();
493 int size = size_given_klass(k);
494 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
495 return size;
496 }
497
498 template <typename OopClosureType>
499 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
500 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass());
501 }
502
503 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
504 return obj == NULL || obj->klass()->is_subtype_of(klass);
505 }
506
507 intptr_t oopDesc::identity_hash() {
508 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
509 // Note: The mark must be read into local variable to avoid concurrent updates.
510 markOop mrk = mark();
511 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
512 return mrk->hash();
513 } else if (mrk->is_marked()) {
514 return mrk->hash();
515 } else {
516 return slow_identity_hash();
517 }
518 }
519
520 bool oopDesc::has_displaced_mark_raw() const {
521 return mark_raw()->has_displaced_mark_helper();
522 }
523
524 markOop oopDesc::displaced_mark_raw() const {
525 return mark_raw()->displaced_mark_helper();
526 }
527
528 void oopDesc::set_displaced_mark_raw(markOop m) {
529 mark_raw()->set_displaced_mark_helper(m);
530 }
531
532 #endif // SHARE_OOPS_OOP_INLINE_HPP