1 /*
2 * Copyright (c) 1997, 2018, 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
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23 */
24
25 #ifndef SHARE_VM_OOPS_OOP_INLINE_HPP
26 #define SHARE_VM_OOPS_OOP_INLINE_HPP
27
28 #include "gc/shared/ageTable.hpp"
29 #include "gc/shared/collectedHeap.inline.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "gc/shared/generation.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/klass.inline.hpp"
36 #include "oops/markOop.inline.hpp"
37 #include "oops/oop.hpp"
38 #include "runtime/atomic.hpp"
39 #include "runtime/orderAccess.inline.hpp"
40 #include "runtime/os.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/macros.hpp"
43
44 // Implementation of all inlined member functions defined in oop.hpp
45 // We need a separate file to avoid circular references
46
47 inline markOop oopDesc::mark() const {
48 return HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes());
49 }
50
51 inline markOop* oopDesc::mark_addr() const {
52 return (markOop*) &_mark;
53 }
54
55 inline void oopDesc::set_mark(volatile markOop m) {
56 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m);
57 }
58
59 void oopDesc::release_set_mark(markOop m) {
60 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
61 }
62
63 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
64 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark);
65 }
66
67 void oopDesc::init_mark() {
68 set_mark(markOopDesc::prototype_for_object(this));
69 }
70
71 Klass* oopDesc::klass() const {
72 if (UseCompressedClassPointers) {
73 return Klass::decode_klass_not_null(_metadata._compressed_klass);
74 } else {
75 return _metadata._klass;
76 }
77 }
78
79 Klass* oopDesc::klass_or_null() const volatile {
80 if (UseCompressedClassPointers) {
81 return Klass::decode_klass(_metadata._compressed_klass);
82 } else {
83 return _metadata._klass;
84 }
85 }
86
87 Klass* oopDesc::klass_or_null_acquire() const volatile {
88 if (UseCompressedClassPointers) {
89 // Workaround for non-const load_acquire parameter.
90 const volatile narrowKlass* addr = &_metadata._compressed_klass;
91 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
92 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
93 } else {
94 return OrderAccess::load_acquire(&_metadata._klass);
95 }
96 }
97
98 Klass** oopDesc::klass_addr() {
99 // Only used internally and with CMS and will not work with
100 // UseCompressedOops
101 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
102 return (Klass**) &_metadata._klass;
103 }
104
105 narrowKlass* oopDesc::compressed_klass_addr() {
106 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
107 return &_metadata._compressed_klass;
108 }
109
110 #define CHECK_SET_KLASS(k) \
111 do { \
112 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
113 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
114 } while (0)
115
116 void oopDesc::set_klass(Klass* k) {
117 CHECK_SET_KLASS(k);
118 if (UseCompressedClassPointers) {
119 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
120 } else {
121 *klass_addr() = k;
122 }
123 }
124
125 void oopDesc::release_set_klass(Klass* k) {
126 CHECK_SET_KLASS(k);
127 if (UseCompressedClassPointers) {
128 OrderAccess::release_store(compressed_klass_addr(),
129 Klass::encode_klass_not_null(k));
130 } else {
131 OrderAccess::release_store(klass_addr(), k);
132 }
133 }
134
135 #undef CHECK_SET_KLASS
136
137 int oopDesc::klass_gap() const {
138 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
139 }
140
141 void oopDesc::set_klass_gap(int v) {
142 if (UseCompressedClassPointers) {
143 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
144 }
145 }
146
147 void oopDesc::set_klass_to_list_ptr(oop k) {
148 // This is only to be used during GC, for from-space objects, so no
149 // barrier is needed.
150 if (UseCompressedClassPointers) {
151 _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k); // may be null (parnew overflow handling)
152 } else {
153 _metadata._klass = (Klass*)(address)k;
154 }
155 }
156
157 oop oopDesc::list_ptr_from_klass() {
158 // This is only to be used during GC, for from-space objects.
159 if (UseCompressedClassPointers) {
160 return decode_heap_oop((narrowOop)_metadata._compressed_klass);
161 } else {
162 // Special case for GC
163 return (oop)(address)_metadata._klass;
164 }
165 }
166
167 bool oopDesc::is_a(Klass* k) const {
168 return klass()->is_subtype_of(k);
169 }
170
171 int oopDesc::size() {
172 return size_given_klass(klass());
173 }
174
175 int oopDesc::size_given_klass(Klass* klass) {
176 int lh = klass->layout_helper();
177 int s;
178
179 // lh is now a value computed at class initialization that may hint
180 // at the size. For instances, this is positive and equal to the
181 // size. For arrays, this is negative and provides log2 of the
182 // array element size. For other oops, it is zero and thus requires
183 // a virtual call.
184 //
185 // We go to all this trouble because the size computation is at the
186 // heart of phase 2 of mark-compaction, and called for every object,
187 // alive or dead. So the speed here is equal in importance to the
188 // speed of allocation.
189
190 if (lh > Klass::_lh_neutral_value) {
191 if (!Klass::layout_helper_needs_slow_path(lh)) {
192 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
193 } else {
194 s = klass->oop_size(this);
195 }
196 } else if (lh <= Klass::_lh_neutral_value) {
197 // The most common case is instances; fall through if so.
198 if (lh < Klass::_lh_neutral_value) {
199 // Second most common case is arrays. We have to fetch the
200 // length of the array, shift (multiply) it appropriately,
201 // up to wordSize, add the header, and align to object size.
202 size_t size_in_bytes;
203 size_t array_length = (size_t) ((arrayOop)this)->length();
204 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
205 size_in_bytes += Klass::layout_helper_header_size(lh);
206
207 // This code could be simplified, but by keeping array_header_in_bytes
208 // in units of bytes and doing it this way we can round up just once,
209 // skipping the intermediate round to HeapWordSize.
210 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
211
212 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
213 // of an "old copy" of an object array in the young gen so it indicates
214 // the grey portion of an already copied array. This will cause the first
215 // disjunct below to fail if the two comparands are computed across such
216 // a concurrent change.
217 // ParNew also runs with promotion labs (which look like int
218 // filler arrays) which are subject to changing their declared size
219 // when finally retiring a PLAB; this also can cause the first disjunct
220 // to fail for another worker thread that is concurrently walking the block
221 // offset table. Both these invariant failures are benign for their
222 // current uses; we relax the assertion checking to cover these two cases below:
223 // is_objArray() && is_forwarded() // covers first scenario above
224 // || is_typeArray() // covers second scenario above
225 // If and when UseParallelGC uses the same obj array oop stealing/chunking
226 // technique, we will need to suitably modify the assertion.
227 assert((s == klass->oop_size(this)) ||
228 (Universe::heap()->is_gc_active() &&
229 ((is_typeArray() && UseConcMarkSweepGC) ||
230 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
231 "wrong array object size");
232 } else {
233 // Must be zero, so bite the bullet and take the virtual call.
234 s = klass->oop_size(this);
235 }
236 }
237
238 assert(s > 0, "Oop size must be greater than zero, not %d", s);
239 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
240 return s;
241 }
242
243 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
244 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
245 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
246 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
247
248 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
249 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
250
251 template <class T>
252 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
253
254 // Functions for getting and setting oops within instance objects.
255 // If the oops are compressed, the type passed to these overloaded functions
256 // is narrowOop. All functions are overloaded so they can be called by
257 // template functions without conditionals (the compiler instantiates via
258 // the right type and inlines the appopriate code).
259
260 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
261 // offset from the heap base. Saving the check for null can save instructions
262 // in inner GC loops so these are separated.
263
264 inline bool check_obj_alignment(oop obj) {
265 return (cast_from_oop<intptr_t>(obj) & MinObjAlignmentInBytesMask) == 0;
266 }
267
268 oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
269 assert(!is_null(v), "narrow oop value can never be zero");
270 address base = Universe::narrow_oop_base();
271 int shift = Universe::narrow_oop_shift();
272 oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
273 assert(check_obj_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result));
274 return result;
275 }
276
277 oop oopDesc::decode_heap_oop(narrowOop v) {
278 return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
279 }
280
281 narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
282 assert(!is_null(v), "oop value can never be zero");
283 assert(check_obj_alignment(v), "Address not aligned");
284 assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
285 address base = Universe::narrow_oop_base();
286 int shift = Universe::narrow_oop_shift();
287 uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
288 assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
289 uint64_t result = pd >> shift;
290 assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
291 assert(decode_heap_oop(result) == v, "reversibility");
292 return (narrowOop)result;
293 }
294
295 narrowOop oopDesc::encode_heap_oop(oop v) {
296 return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
297 }
298
299 narrowOop oopDesc::load_heap_oop(narrowOop* p) { return *p; }
300 oop oopDesc::load_heap_oop(oop* p) { return *p; }
301
302 void oopDesc::store_heap_oop(narrowOop* p, narrowOop v) { *p = v; }
303 void oopDesc::store_heap_oop(oop* p, oop v) { *p = v; }
304
305 // Load and decode an oop out of the Java heap into a wide oop.
306 oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
307 return decode_heap_oop_not_null(load_heap_oop(p));
308 }
309
310 // Load and decode an oop out of the heap accepting null
311 oop oopDesc::load_decode_heap_oop(narrowOop* p) {
312 return decode_heap_oop(load_heap_oop(p));
313 }
314
315 oop oopDesc::load_decode_heap_oop_not_null(oop* p) { return *p; }
316 oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
317
318 void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
319 void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
320
321 // Encode and store a heap oop.
322 void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
323 *p = encode_heap_oop_not_null(v);
324 }
325
326 // Encode and store a heap oop allowing for null.
327 void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
328 *p = encode_heap_oop(v);
329 }
330
331 template <DecoratorSet decorators>
332 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
333 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
334
335 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
336
337 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
338 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
339
340 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
341 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
342
343 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
344 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
345
346 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
347 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
348
349 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
350 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
351
352 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
353 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
354
355 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
356 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
357
358 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
359 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
360
361 bool oopDesc::is_locked() const {
362 return mark()->is_locked();
363 }
364
365 bool oopDesc::is_unlocked() const {
366 return mark()->is_unlocked();
367 }
368
369 bool oopDesc::has_bias_pattern() const {
370 return mark()->has_bias_pattern();
371 }
372
373 // Used only for markSweep, scavenging
374 bool oopDesc::is_gc_marked() const {
375 return mark()->is_marked();
376 }
377
378 // Used by scavengers
379 bool oopDesc::is_forwarded() const {
380 // The extra heap check is needed since the obj might be locked, in which case the
381 // mark would point to a stack location and have the sentinel bit cleared
382 return mark()->is_marked();
383 }
384
385 // Used by scavengers
386 void oopDesc::forward_to(oop p) {
387 assert(check_obj_alignment(p),
388 "forwarding to something not aligned");
389 assert(Universe::heap()->is_in_reserved(p),
390 "forwarding to something not in heap");
391 assert(!is_archive_object(oop(this)) &&
392 !is_archive_object(p),
393 "forwarding archive object");
394 markOop m = markOopDesc::encode_pointer_as_mark(p);
395 assert(m->decode_pointer() == p, "encoding must be reversable");
396 set_mark(m);
397 }
398
399 // Used by parallel scavengers
400 bool oopDesc::cas_forward_to(oop p, markOop compare) {
401 assert(check_obj_alignment(p),
402 "forwarding to something not aligned");
403 assert(Universe::heap()->is_in_reserved(p),
404 "forwarding to something not in heap");
405 markOop m = markOopDesc::encode_pointer_as_mark(p);
406 assert(m->decode_pointer() == p, "encoding must be reversable");
407 return cas_set_mark(m, compare) == compare;
408 }
409
410 #if INCLUDE_ALL_GCS
411 oop oopDesc::forward_to_atomic(oop p) {
412 markOop oldMark = mark();
413 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
414 markOop curMark;
415
416 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
417 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
418
419 while (!oldMark->is_marked()) {
420 curMark = Atomic::cmpxchg(forwardPtrMark, &_mark, oldMark);
421 assert(is_forwarded(), "object should have been forwarded");
422 if (curMark == oldMark) {
423 return NULL;
424 }
425 // If the CAS was unsuccessful then curMark->is_marked()
426 // should return true as another thread has CAS'd in another
427 // forwarding pointer.
428 oldMark = curMark;
429 }
430 return forwardee();
431 }
432 #endif
433
434 // Note that the forwardee is not the same thing as the displaced_mark.
435 // The forwardee is used when copying during scavenge and mark-sweep.
436 // It does need to clear the low two locking- and GC-related bits.
437 oop oopDesc::forwardee() const {
438 return (oop) mark()->decode_pointer();
439 }
440
441 // The following method needs to be MT safe.
442 uint oopDesc::age() const {
443 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
444 if (has_displaced_mark()) {
445 return displaced_mark()->age();
446 } else {
447 return mark()->age();
448 }
449 }
450
451 void oopDesc::incr_age() {
452 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
453 if (has_displaced_mark()) {
454 set_displaced_mark(displaced_mark()->incr_age());
455 } else {
456 set_mark(mark()->incr_age());
457 }
458 }
459
460 #if INCLUDE_ALL_GCS
461 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
462 klass()->oop_pc_follow_contents(this, cm);
463 }
464
465 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
466 Klass* k = klass();
467 if (!k->is_typeArray_klass()) {
468 // It might contain oops beyond the header, so take the virtual call.
469 k->oop_pc_update_pointers(this, cm);
470 }
471 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
472 }
473
474 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
475 Klass* k = klass();
476 if (!k->is_typeArray_klass()) {
477 // It might contain oops beyond the header, so take the virtual call.
478 k->oop_ps_push_contents(this, pm);
479 }
480 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
481 }
482 #endif // INCLUDE_ALL_GCS
483
484 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
485 \
486 void oopDesc::oop_iterate(OopClosureType* blk) { \
487 klass()->oop_oop_iterate##nv_suffix(this, blk); \
488 } \
489 \
490 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \
491 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
492 }
493
494 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
495 \
496 int oopDesc::oop_iterate_size(OopClosureType* blk) { \
497 Klass* k = klass(); \
498 int size = size_given_klass(k); \
499 k->oop_oop_iterate##nv_suffix(this, blk); \
500 return size; \
501 } \
502 \
503 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \
504 Klass* k = klass(); \
505 int size = size_given_klass(k); \
506 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
507 return size; \
508 }
509
510 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
511 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
512 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
513 NoHeaderExtendedOopClosure cl(blk);
514 return oop_iterate_size(&cl);
515 }
516
517 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
518 NoHeaderExtendedOopClosure cl(blk);
519 return oop_iterate_size(&cl, mr);
520 }
521
522 #if INCLUDE_ALL_GCS
523 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
524 \
525 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \
526 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \
527 }
528 #else
529 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
530 #endif // INCLUDE_ALL_GCS
531
532 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \
533 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
534 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
535 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
536
537 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
538 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
539
540 intptr_t oopDesc::identity_hash() {
541 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
542 // Note: The mark must be read into local variable to avoid concurrent updates.
543 markOop mrk = mark();
544 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
545 return mrk->hash();
546 } else if (mrk->is_marked()) {
547 return mrk->hash();
548 } else {
549 return slow_identity_hash();
550 }
551 }
552
553 bool oopDesc::has_displaced_mark() const {
554 return mark()->has_displaced_mark_helper();
555 }
556
557 markOop oopDesc::displaced_mark() const {
558 return mark()->displaced_mark_helper();
559 }
560
561 void oopDesc::set_displaced_mark(markOop m) {
562 mark()->set_displaced_mark_helper(m);
563 }
564
565 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP