1 /*
  2  * Copyright (c) 1997, 2026, 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.
 22  *
 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/iterator.inline.hpp"
 31 #include "memory/universe.hpp"
 32 #include "oops/access.inline.hpp"
 33 #include "oops/arrayKlass.hpp"
 34 #include "oops/arrayOop.hpp"
 35 #include "oops/compressedKlass.inline.hpp"
 36 #include "oops/instanceKlass.hpp"
 37 #include "oops/markWord.inline.hpp"
 38 #include "oops/objLayout.inline.hpp"
 39 #include "oops/oopsHierarchy.hpp"
 40 #include "runtime/atomicAccess.hpp"
 41 #include "runtime/globals.hpp"
 42 #include "utilities/align.hpp"
 43 #include "utilities/debug.hpp"
 44 #include "utilities/globalDefinitions.hpp"
 45 #include "utilities/macros.hpp"
 46 
 47 // Implementation of all inlined member functions defined in oop.hpp
 48 // We need a separate file to avoid circular references
 49 
 50 void* oopDesc::base_addr() { return this; }
 51 const void* oopDesc::base_addr() const { return this; }
 52 
 53 markWord oopDesc::mark() const {
 54   return AtomicAccess::load(&_mark);
 55 }
 56 
 57 markWord oopDesc::mark_acquire() const {
 58   return AtomicAccess::load_acquire(&_mark);
 59 }
 60 
 61 void oopDesc::set_mark(markWord m) {
 62   if (UseCompactObjectHeaders) {
 63     AtomicAccess::store(reinterpret_cast<uint32_t volatile*>(&_mark), m.value32());
 64   } else {
 65     AtomicAccess::store(&_mark, m);
 66   }
 67 }
 68 
 69 void oopDesc::set_mark_full(markWord m) {
 70   AtomicAccess::store(&_mark, m);
 71 }
 72 
 73 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 74   if (UseCompactObjectHeaders) {
 75     *(uint32_t*)(((char*)mem) + mark_offset_in_bytes()) = m.value32();
 76   } else {
 77     *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 78   }
 79 }
 80 
 81 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
 82   if (UseCompactObjectHeaders) {
 83     AtomicAccess::release_store((uint32_t*)(((char*)mem) + mark_offset_in_bytes()), m.value32());
 84   } else {
 85     AtomicAccess::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
 86   }
 87 }
 88 
 89 void oopDesc::release_set_mark(markWord m) {
 90   if (UseCompactObjectHeaders) {
 91     AtomicAccess::release_store(reinterpret_cast<uint32_t volatile*>(&_mark), m.value32());
 92   } else {
 93     AtomicAccess::release_store(&_mark, m);
 94   }
 95 }
 96 
 97 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 98   return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark);
 99 }
100 
101 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
102   return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark, order);
103 }
104 
105 markWord oopDesc::prototype_mark() const {
106   if (UseCompactObjectHeaders) {
107     return klass()->prototype_header();
108   } else {
109     return markWord::prototype();
110   }
111 }
112 
113 void oopDesc::init_mark() {
114   set_mark(prototype_mark());
115 }
116 
117 void oopDesc::reinit_mark() {
118   if (UseCompactObjectHeaders) {
119     markWord m = prototype_mark().copy_hashctrl_from(mark());
120     assert(m.is_neutral(), "must be neutral");
121     set_mark(m);
122   } else {
123     set_mark(prototype_mark());
124   }
125 }
126 
127 Klass* oopDesc::klass() const {
128   return CompressedKlassPointers::decode_not_null(narrow_klass());
129 }
130 
131 Klass* oopDesc::klass_or_null() const {
132   return CompressedKlassPointers::decode(narrow_klass());
133 }
134 
135 Klass* oopDesc::klass_or_null_acquire() const {
136   return CompressedKlassPointers::decode(narrow_klass_acquire());
137 }
138 
139 Klass* oopDesc::klass_without_asserts() const {
140   return CompressedKlassPointers::decode_without_asserts(narrow_klass());
141 }
142 
143 narrowKlass oopDesc::narrow_klass() const {
144   switch (ObjLayout::klass_mode()) {
145     case ObjLayout::Compact:
146       return mark().narrow_klass();
147     case ObjLayout::Compressed:
148       return _compressed_klass;
149     default:
150       ShouldNotReachHere();
151   }
152 }
153 
154 narrowKlass oopDesc::narrow_klass_acquire() const {
155   switch (ObjLayout::klass_mode()) {
156     case ObjLayout::Compact:
157       return mark_acquire().narrow_klass();
158     case ObjLayout::Compressed:
159       return AtomicAccess::load_acquire(&_compressed_klass);
160     default:
161       ShouldNotReachHere();
162   }
163 }
164 
165 void oopDesc::set_klass(Klass* k) {
166   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
167   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
168   _compressed_klass = CompressedKlassPointers::encode_not_null(k);
169 }
170 
171 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
172   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
173   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
174   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
175   AtomicAccess::release_store((narrowKlass*)raw_mem, CompressedKlassPointers::encode_not_null(k));
176 }
177 
178 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
179   assert(has_klass_gap(), "precondition");
180   *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
181 }
182 
183 bool oopDesc::is_a(Klass* k) const {
184   return klass()->is_subtype_of(k);
185 }
186 
187 size_t oopDesc::size_given_mark_and_klass(markWord mrk, const Klass* kls) {
188   size_t sz = base_size_given_klass(mrk, kls);
189   if (UseCompactObjectHeaders) {
190     assert(!mrk.has_displaced_mark_helper(), "must not be displaced");
191     if (mrk.is_expanded() && kls->expand_for_hash(cast_to_oop(this), mrk)) {
192       sz = align_object_size(sz + 1);
193     }
194   }
195   return sz;
196 }
197 
198 size_t oopDesc::size_forwarded() {
199   assert(is_forwarded(), "must be forwarded");
200   markWord m = mark();
201   oop fwd = forwardee(m);
202   if (!UseCompactObjectHeaders) {
203     return fwd->size();
204   }
205   markWord fm = fwd->mark();
206   Klass* klass = fm.klass();
207   if (m.is_forward_expanded()) {
208     // Forwardee was expanded during copy but the original was not.
209     // Original must have base size.
210     return fwd->base_size_given_klass(fm, klass);
211   }
212   // Original and copy have same size (whether expanded or not).
213   return fwd->size_given_mark_and_klass(fm, klass);
214 }
215 
216 size_t oopDesc::copy_size(size_t size, markWord mark) const {
217   if (UseCompactObjectHeaders) {
218     assert(!mark.has_displaced_mark_helper(), "must not be displaced");
219     Klass* klass = mark.klass();
220     if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
221       size = align_object_size(size + 1);
222     }
223   }
224   assert(is_object_aligned(size), "Oop size is not properly aligned: %zu", size);
225   return size;
226 }
227 
228 size_t oopDesc::copy_size_cds(size_t size, markWord mark) const {
229   if (UseCompactObjectHeaders) {
230     assert(!mark.has_displaced_mark_helper(), "must not be displaced");
231     Klass* klass = mark.klass();
232     if (mark.is_not_hashed_expanded()) {
233       assert(klass->expand_for_hash(cast_to_oop(this), mark), "must be?");
234     }
235     if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
236       size = align_object_size(size + 1);
237     }
238     if (mark.is_not_hashed_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
239       size = align_object_size(size - ObjectAlignmentInBytes / HeapWordSize);
240     }
241   }
242   assert(is_object_aligned(size), "Oop size is not properly aligned: %zu", size);
243   return size;
244 }
245 
246 size_t oopDesc::size()  {
247   return size_given_mark_and_klass(mark(), klass());
248 }
249 
250 size_t oopDesc::base_size_given_klass(markWord mrk, const Klass* klass)  {
251   int lh = klass->layout_helper();
252   size_t s;
253 
254   // lh is now a value computed at class initialization that may hint
255   // at the size.  For instances, this is positive and equal to the
256   // size.  For arrays, this is negative and provides log2 of the
257   // array element size.  For other oops, it is zero and thus requires
258   // a virtual call.
259   //
260   // We go to all this trouble because the size computation is at the
261   // heart of phase 2 of mark-compaction, and called for every object,
262   // alive or dead.  So the speed here is equal in importance to the
263   // speed of allocation.
264 
265   if (lh > Klass::_lh_neutral_value) {
266     if (!Klass::layout_helper_needs_slow_path(lh)) {
267       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
268     } else {
269       s = klass->oop_size(this, mrk);
270     }
271   } else if (lh <= Klass::_lh_neutral_value) {
272     // The most common case is instances; fall through if so.
273     if (lh < Klass::_lh_neutral_value) {
274       // Second most common case is arrays.  We have to fetch the
275       // length of the array, shift (multiply) it appropriately,
276       // up to wordSize, add the header, and align to object size.
277       size_t size_in_bytes;
278       size_t array_length;
279 #ifdef _LP64
280       if (UseCompactObjectHeaders) {
281         array_length = (size_t) mrk.array_length();
282       } else
283 #endif
284         array_length = (size_t)((arrayOop)this)->length();
285 
286       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
287       size_in_bytes += Klass::layout_helper_header_size(lh);
288 
289       // This code could be simplified, but by keeping array_header_in_bytes
290       // in units of bytes and doing it this way we can round up just once,
291       // skipping the intermediate round to HeapWordSize.
292       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
293       if (s != klass->oop_size(this, mrk)) {
294         tty->print_cr("length: %zu", array_length);
295         tty->print_cr("log element size: %d", Klass::layout_helper_log2_element_size(lh));
296         tty->print_cr("is_objArray: %s", BOOL_TO_STR(klass->is_objArray_klass()));
297       }
298       assert(s == klass->oop_size(this, mrk), "wrong array object size, s: %zu, oop_size: %zu", s, klass->oop_size(this, mrk));
299     } else {
300       // Must be zero, so bite the bullet and take the virtual call.
301       s = klass->oop_size(this, mrk);
302     }
303   }
304 
305   assert(s > 0, "Oop size must be greater than zero, not %zu", s);
306   assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
307   return s;
308 }
309 
310 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
311 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
312 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
313 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
314 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
315 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
316 
317 template<typename T>
318 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
319 
320 template <typename T>
321 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
322 
323 template <DecoratorSet decorators>
324 inline oop  oopDesc::obj_field_access(int offset) const             { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
325 inline oop  oopDesc::obj_field(int offset) const                    { return HeapAccess<>::oop_load_at(as_oop(), offset);  }
326 
327 inline void oopDesc::obj_field_put(int offset, oop value)           { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
328 template <DecoratorSet decorators>
329 inline void oopDesc::obj_field_put_access(int offset, oop value)    { HeapAccess<decorators>::oop_store_at(as_oop(), offset, value); }
330 
331 inline jbyte oopDesc::byte_field(int offset) const                  { return *field_addr<jbyte>(offset);  }
332 inline void  oopDesc::byte_field_put(int offset, jbyte value)       { *field_addr<jbyte>(offset) = value; }
333 
334 inline jchar oopDesc::char_field(int offset) const                  { return *field_addr<jchar>(offset);  }
335 inline void  oopDesc::char_field_put(int offset, jchar value)       { *field_addr<jchar>(offset) = value; }
336 
337 inline jboolean oopDesc::bool_field(int offset) const               { return *field_addr<jboolean>(offset); }
338 inline void     oopDesc::bool_field_put(int offset, jboolean value) { *field_addr<jboolean>(offset) = jboolean(value & 1); }
339 inline jboolean oopDesc::bool_field_volatile(int offset) const      { return RawAccess<MO_SEQ_CST>::load(field_addr<jboolean>(offset)); }
340 inline void     oopDesc::bool_field_put_volatile(int offset, jboolean value) { RawAccess<MO_SEQ_CST>::store(field_addr<jboolean>(offset), jboolean(value & 1)); }
341 inline jshort oopDesc::short_field(int offset) const                { return *field_addr<jshort>(offset);   }
342 inline void   oopDesc::short_field_put(int offset, jshort value)    { *field_addr<jshort>(offset) = value;  }
343 
344 inline jint oopDesc::int_field(int offset) const                    { return *field_addr<jint>(offset);     }
345 inline void oopDesc::int_field_put(int offset, jint value)          { *field_addr<jint>(offset) = value;    }
346 inline jint oopDesc::int_field_relaxed(int offset) const            { return AtomicAccess::load(field_addr<jint>(offset)); }
347 inline void oopDesc::int_field_put_relaxed(int offset, jint value)  { AtomicAccess::store(field_addr<jint>(offset), value); }
348 
349 inline jlong oopDesc::long_field(int offset) const                  { return *field_addr<jlong>(offset);    }
350 inline void  oopDesc::long_field_put(int offset, jlong value)       { *field_addr<jlong>(offset) = value;   }
351 
352 inline jfloat oopDesc::float_field(int offset) const                { return *field_addr<jfloat>(offset);   }
353 inline void   oopDesc::float_field_put(int offset, jfloat value)    { *field_addr<jfloat>(offset) = value;  }
354 
355 inline jdouble oopDesc::double_field(int offset) const              { return *field_addr<jdouble>(offset);  }
356 inline void    oopDesc::double_field_put(int offset, jdouble value) { *field_addr<jdouble>(offset) = value; }
357 
358 bool oopDesc::is_locked() const {
359   return mark().is_locked();
360 }
361 
362 bool oopDesc::is_unlocked() const {
363   return mark().is_unlocked();
364 }
365 
366 bool oopDesc::is_gc_marked() const {
367   return mark().is_marked();
368 }
369 
370 // Used by scavengers
371 bool oopDesc::is_forwarded() const {
372   return mark().is_forwarded();
373 }
374 
375 bool oopDesc::is_self_forwarded() const {
376   return mark().is_self_forwarded();
377 }
378 
379 // Used by scavengers
380 void oopDesc::forward_to(oop p) {
381   assert(cast_from_oop<oopDesc*>(p) != this,
382          "must not be used for self-forwarding, use forward_to_self() instead");
383   markWord m = markWord::encode_pointer_as_mark(p);
384   if (UseCompactObjectHeaders && p->mark().is_expanded() && !mark().is_expanded()) {
385     m = m.set_forward_expanded();
386   }
387   assert(m.decode_pointer() == p, "encoding must be reversible");
388   set_mark_full(m);
389 }
390 
391 void oopDesc::forward_to_self() {
392   set_mark(mark().set_self_forwarded());
393 }
394 
395 void oopDesc::reset_forwarded() {
396   markWord m = mark();
397   if (m.is_self_forwarded()) {
398     unset_self_forwarded();
399   } else if (m.is_forwarded()) {
400     // Restore Klass* and hash-bits in the header,
401     // for correct iteration.
402     markWord fwd_mark = forwardee()->mark();
403     if (m.is_forward_expanded()) {
404       // Un-expand original object.
405       fwd_mark = fwd_mark.set_hashed_not_expanded();
406     }
407     set_mark_full(fwd_mark);
408   }
409 }
410 
411 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
412   markWord old_mark = cas_set_mark(new_mark, compare, order);
413   if (old_mark == compare) {
414     return nullptr;
415   } else {
416     assert(old_mark.is_forwarded(), "must be forwarded here");
417     return forwardee(old_mark);
418   }
419 }
420 
421 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
422   assert(cast_from_oop<oopDesc*>(p) != this,
423          "must not be used for self-forwarding, use forward_to_self_atomic() instead");
424   markWord m = markWord::encode_pointer_as_mark(p);
425   if (UseCompactObjectHeaders && compare.is_hashed_not_expanded()) {
426     m = m.set_forward_expanded();
427   }
428   assert(forwardee(m) == p, "encoding must be reversible");
429   return cas_set_forwardee(m, compare, order);
430 }
431 
432 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
433   markWord new_mark = old_mark.set_self_forwarded();
434   assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
435   return cas_set_forwardee(new_mark, old_mark, order);
436 }
437 
438 oop oopDesc::forwardee(markWord mark) const {
439   assert(mark.is_forwarded(), "only decode when actually forwarded");
440   if (mark.is_self_forwarded()) {
441     return cast_to_oop(this);
442   } else {
443     return mark.forwardee();
444   }
445 }
446 
447 // Note that the forwardee is not the same thing as the displaced_mark.
448 // The forwardee is used when copying during scavenge and mark-sweep.
449 // It does need to clear the low two locking- and GC-related bits.
450 oop oopDesc::forwardee() const {
451   return forwardee(mark());
452 }
453 
454 void oopDesc::unset_self_forwarded() {
455   set_mark(mark().unset_self_forwarded());
456 }
457 
458 // The following method needs to be MT safe.
459 uint oopDesc::age() const {
460   markWord m = mark();
461   assert(!m.is_marked(), "Attempt to read age from forwarded mark");
462   if (m.has_displaced_mark_helper()) {
463     return m.displaced_mark_helper().age();
464   } else {
465     return m.age();
466   }
467 }
468 
469 void oopDesc::incr_age() {
470   markWord m = mark();
471   assert(!m.is_marked(), "Attempt to increment age of forwarded mark");
472   if (m.has_displaced_mark_helper()) {
473     m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
474   } else {
475     set_mark(m.incr_age());
476   }
477 }
478 
479 template <typename OopClosureType>
480 void oopDesc::oop_iterate(OopClosureType* cl) {
481   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
482 }
483 
484 template <typename OopClosureType>
485 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
486   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
487 }
488 
489 template <typename OopClosureType>
490 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
491   Klass* k = klass();
492   size_t size = size_given_mark_and_klass(mark(), k);
493   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
494   return size;
495 }
496 
497 template <typename OopClosureType>
498 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
499   Klass* k = klass();
500   size_t size = size_given_mark_and_klass(mark(), k);
501   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
502   return size;
503 }
504 
505 template <typename OopClosureType>
506 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
507   oop_iterate_backwards(cl, klass());
508 }
509 
510 template <typename OopClosureType>
511 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
512   // In this assert, we cannot safely access the Klass* with compact headers.
513   assert(k == klass(), "wrong klass");
514   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
515 }
516 
517 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
518   return obj == nullptr || obj->klass()->is_subtype_of(klass);
519 }
520 
521 intptr_t oopDesc::identity_hash() {
522   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
523   // Note: The mark must be read into local variable to avoid concurrent updates.
524   if (UseCompactObjectHeaders) {
525     markWord mrk = mark();
526     if (mrk.is_hashed_expanded()) {
527       Klass* klass = mrk.klass();
528       return int_field(klass->hash_offset_in_bytes(cast_to_oop(this), mrk));
529     }
530     // Fall-through to slow-case.
531   } else {
532     markWord mrk = mark();
533     if (mrk.is_unlocked() && !mrk.has_no_hash()) {
534       return mrk.hash();
535     } else if (mrk.is_marked()) {
536       return mrk.hash();
537     }
538     // Fall-through to slow-case.
539   }
540   return slow_identity_hash();
541 }
542 
543 // This checks fast simple case of whether the oop has_no_hash,
544 // to optimize JVMTI table lookup.
545 bool oopDesc::fast_no_hash_check() {
546   markWord mrk = mark_acquire();
547   assert(!mrk.is_marked(), "should never be marked");
548   return (UseCompactObjectHeaders || mrk.is_unlocked()) && mrk.has_no_hash();
549 }
550 
551 bool oopDesc::has_displaced_mark() const {
552   return mark().has_displaced_mark_helper();
553 }
554 
555 markWord oopDesc::displaced_mark() const {
556   return mark().displaced_mark_helper();
557 }
558 
559 void oopDesc::set_displaced_mark(markWord m) {
560   mark().set_displaced_mark_helper(m);
561 }
562 
563 bool oopDesc::mark_must_be_preserved() const {
564   return mark_must_be_preserved(mark());
565 }
566 
567 bool oopDesc::mark_must_be_preserved(markWord m) const {
568   return m.must_be_preserved();
569 }
570 
571 inline void oopDesc::initialize_hash_if_necessary(oop obj) {
572   if (!UseCompactObjectHeaders) {
573     return;
574   }
575   markWord m = mark();
576   assert(!m.has_displaced_mark_helper(), "must not be displaced header");
577   if (m.is_hashed_not_expanded()) {
578     set_mark(initialize_hash_if_necessary(obj, m.klass(), m));
579   }
580 }
581 
582 
583 #endif // SHARE_OOPS_OOP_INLINE_HPP