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src/hotspot/share/oops/oop.inline.hpp

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 43 #include "utilities/debug.hpp"
 44 #include "utilities/macros.hpp"
 45 #include "utilities/globalDefinitions.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 markWord oopDesc::mark() const {
 51   return Atomic::load(&_mark);
 52 }
 53 
 54 markWord oopDesc::mark_acquire() const {
 55   return Atomic::load_acquire(&_mark);
 56 }
 57 
 58 markWord* oopDesc::mark_addr() const {
 59   return (markWord*) &_mark;
 60 }
 61 
 62 void oopDesc::set_mark(markWord m) {








 63   Atomic::store(&_mark, m);
 64 }
 65 
 66 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 67   *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;




 68 }
 69 
 70 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
 71   Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);




 72 }
 73 
 74 void oopDesc::release_set_mark(markWord m) {
 75   Atomic::release_store(&_mark, m);




 76 }
 77 
 78 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 79   return Atomic::cmpxchg(&_mark, old_mark, new_mark);
 80 }
 81 
 82 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
 83   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
 84 }
 85 
 86 markWord oopDesc::prototype_mark() const {
 87   if (UseCompactObjectHeaders) {
 88     return klass()->prototype_header();
 89   } else {
 90     return markWord::prototype();
 91   }
 92 }
 93 
 94 void oopDesc::init_mark() {
 95   set_mark(prototype_mark());






 96 }
 97 
 98 Klass* oopDesc::klass() const {
 99   switch (ObjLayout::klass_mode()) {
100     case ObjLayout::Compact:
101       return mark().klass();
102     case ObjLayout::Compressed:
103       return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
104     default:
105       return _metadata._klass;
106   }
107 }
108 
109 Klass* oopDesc::klass_or_null() const {
110   switch (ObjLayout::klass_mode()) {
111     case ObjLayout::Compact:
112       return mark().klass_or_null();
113     case ObjLayout::Compressed:
114       return CompressedKlassPointers::decode(_metadata._compressed_klass);
115     default:

155   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
156   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
157   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
158   if (UseCompressedClassPointers) {
159     Atomic::release_store((narrowKlass*)raw_mem,
160                           CompressedKlassPointers::encode_not_null(k));
161   } else {
162     Atomic::release_store((Klass**)raw_mem, k);
163   }
164 }
165 
166 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
167   assert(has_klass_gap(), "precondition");
168   *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
169 }
170 
171 bool oopDesc::is_a(Klass* k) const {
172   return klass()->is_subtype_of(k);
173 }
174 






































175 size_t oopDesc::size()  {
176   return size_given_klass(klass());
177 }
178 
179 size_t oopDesc::size_given_klass(Klass* klass)  {
180   int lh = klass->layout_helper();
181   size_t s;
182 
183   // lh is now a value computed at class initialization that may hint
184   // at the size.  For instances, this is positive and equal to the
185   // size.  For arrays, this is negative and provides log2 of the
186   // array element size.  For other oops, it is zero and thus requires
187   // a virtual call.
188   //
189   // We go to all this trouble because the size computation is at the
190   // heart of phase 2 of mark-compaction, and called for every object,
191   // alive or dead.  So the speed here is equal in importance to the
192   // speed of allocation.
193 
194   if (lh > Klass::_lh_neutral_value) {
195     if (!Klass::layout_helper_needs_slow_path(lh)) {
196       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
197     } else {
198       s = klass->oop_size(this);
199     }
200   } else if (lh <= Klass::_lh_neutral_value) {
201     // The most common case is instances; fall through if so.
202     if (lh < Klass::_lh_neutral_value) {
203       // Second most common case is arrays.  We have to fetch the
204       // length of the array, shift (multiply) it appropriately,
205       // up to wordSize, add the header, and align to object size.
206       size_t size_in_bytes;
207       size_t array_length = (size_t) ((arrayOop)this)->length();







208       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
209       size_in_bytes += Klass::layout_helper_header_size(lh);
210 
211       // This code could be simplified, but by keeping array_header_in_bytes
212       // in units of bytes and doing it this way we can round up just once,
213       // skipping the intermediate round to HeapWordSize.
214       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
215 
216       assert(s == klass->oop_size(this), "wrong array object size");




217     } else {
218       // Must be zero, so bite the bullet and take the virtual call.
219       s = klass->oop_size(this);
220     }
221   }
222 
223   assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
224   assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
225   return s;
226 }
227 
228 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
229 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
230 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
231 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
232 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
233 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
234 
235 template<typename T>
236 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
237 
238 template <typename T>
239 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }

283 
284 bool oopDesc::is_gc_marked() const {
285   return mark().is_marked();
286 }
287 
288 // Used by scavengers
289 bool oopDesc::is_forwarded() const {
290   return mark().is_forwarded();
291 }
292 
293 bool oopDesc::is_self_forwarded() const {
294   return mark().is_self_forwarded();
295 }
296 
297 // Used by scavengers
298 void oopDesc::forward_to(oop p) {
299   assert(cast_from_oop<oopDesc*>(p) != this,
300          "must not be used for self-forwarding, use forward_to_self() instead");
301   markWord m = markWord::encode_pointer_as_mark(p);
302   assert(m.decode_pointer() == p, "encoding must be reversible");
303   set_mark(m);
304 }
305 
306 void oopDesc::forward_to_self() {
307   set_mark(mark().set_self_forwarded());
308 }
309 
310 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
311   markWord old_mark = cas_set_mark(new_mark, compare, order);
312   if (old_mark == compare) {
313     return nullptr;
314   } else {
315     assert(old_mark.is_forwarded(), "must be forwarded here");
316     return forwardee(old_mark);
317   }
318 }
319 
320 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
321   assert(cast_from_oop<oopDesc*>(p) != this,
322          "must not be used for self-forwarding, use forward_to_self_atomic() instead");
323   markWord m = markWord::encode_pointer_as_mark(p);

368   if (m.has_displaced_mark_helper()) {
369     m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
370   } else {
371     set_mark(m.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   // In this assert, we cannot safely access the Klass* with compact headers.
409   assert(k == klass(), "wrong klass");
410   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
411 }
412 
413 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
414   return obj == nullptr || obj->klass()->is_subtype_of(klass);
415 }
416 
417 intptr_t oopDesc::identity_hash() {
418   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
419   // Note: The mark must be read into local variable to avoid concurrent updates.
420   markWord mrk = mark();
421   if (mrk.is_unlocked() && !mrk.has_no_hash()) {
422     return mrk.hash();
423   } else if (mrk.is_marked()) {
424     return mrk.hash();


425   } else {
426     return slow_identity_hash();






427   }

428 }
429 
430 // This checks fast simple case of whether the oop has_no_hash,
431 // to optimize JVMTI table lookup.
432 bool oopDesc::fast_no_hash_check() {
433   markWord mrk = mark_acquire();
434   assert(!mrk.is_marked(), "should never be marked");
435   return mrk.is_unlocked() && mrk.has_no_hash();
436 }
437 
438 bool oopDesc::has_displaced_mark() const {
439   return mark().has_displaced_mark_helper();
440 }
441 
442 markWord oopDesc::displaced_mark() const {
443   return mark().displaced_mark_helper();
444 }
445 
446 void oopDesc::set_displaced_mark(markWord m) {
447   mark().set_displaced_mark_helper(m);
448 }
449 
450 bool oopDesc::mark_must_be_preserved() const {
451   return mark_must_be_preserved(mark());
452 }
453 
454 bool oopDesc::mark_must_be_preserved(markWord m) const {
455   return m.must_be_preserved(this);
456 }
457 













458 #endif // SHARE_OOPS_OOP_INLINE_HPP

 43 #include "utilities/debug.hpp"
 44 #include "utilities/macros.hpp"
 45 #include "utilities/globalDefinitions.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 markWord oopDesc::mark() const {
 51   return Atomic::load(&_mark);
 52 }
 53 
 54 markWord oopDesc::mark_acquire() const {
 55   return Atomic::load_acquire(&_mark);
 56 }
 57 
 58 markWord* oopDesc::mark_addr() const {
 59   return (markWord*) &_mark;
 60 }
 61 
 62 void oopDesc::set_mark(markWord m) {
 63   if (UseCompactObjectHeaders) {
 64     Atomic::store(reinterpret_cast<uint32_t volatile*>(&_mark), m.value32());
 65   } else {
 66     Atomic::store(&_mark, m);
 67   }
 68 }
 69 
 70 void oopDesc::set_mark_full(markWord m) {
 71   Atomic::store(&_mark, m);
 72 }
 73 
 74 void oopDesc::set_mark(HeapWord* mem, markWord m) {
 75   if (UseCompactObjectHeaders) {
 76     *(uint32_t*)(((char*)mem) + mark_offset_in_bytes()) = m.value32();
 77   } else {
 78     *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
 79   }
 80 }
 81 
 82 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
 83   if (UseCompactObjectHeaders) {
 84     Atomic::release_store((uint32_t*)(((char*)mem) + mark_offset_in_bytes()), m.value32());
 85   } else {
 86     Atomic::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
 87   }
 88 }
 89 
 90 void oopDesc::release_set_mark(markWord m) {
 91   if (UseCompactObjectHeaders) {
 92     Atomic::release_store(reinterpret_cast<uint32_t volatile*>(&_mark), m.value32());
 93   } else {
 94     Atomic::release_store(&_mark, m);
 95   }
 96 }
 97 
 98 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
 99   return Atomic::cmpxchg(&_mark, old_mark, new_mark);
100 }
101 
102 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
103   return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
104 }
105 
106 markWord oopDesc::prototype_mark() const {
107   if (UseCompactObjectHeaders) {
108     return klass()->prototype_header();
109   } else {
110     return markWord::prototype();
111   }
112 }
113 
114 void oopDesc::init_mark() {
115   if (UseCompactObjectHeaders) {
116     markWord m = prototype_mark().copy_hashctrl_from(mark());
117     assert(m.is_neutral(), "must be neutral");
118     set_mark(m);
119   } else {
120     set_mark(prototype_mark());
121   }
122 }
123 
124 Klass* oopDesc::klass() const {
125   switch (ObjLayout::klass_mode()) {
126     case ObjLayout::Compact:
127       return mark().klass();
128     case ObjLayout::Compressed:
129       return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
130     default:
131       return _metadata._klass;
132   }
133 }
134 
135 Klass* oopDesc::klass_or_null() const {
136   switch (ObjLayout::klass_mode()) {
137     case ObjLayout::Compact:
138       return mark().klass_or_null();
139     case ObjLayout::Compressed:
140       return CompressedKlassPointers::decode(_metadata._compressed_klass);
141     default:

181   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
182   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
183   char* raw_mem = ((char*)mem + klass_offset_in_bytes());
184   if (UseCompressedClassPointers) {
185     Atomic::release_store((narrowKlass*)raw_mem,
186                           CompressedKlassPointers::encode_not_null(k));
187   } else {
188     Atomic::release_store((Klass**)raw_mem, k);
189   }
190 }
191 
192 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
193   assert(has_klass_gap(), "precondition");
194   *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
195 }
196 
197 bool oopDesc::is_a(Klass* k) const {
198   return klass()->is_subtype_of(k);
199 }
200 
201 size_t oopDesc::size_given_mark_and_klass(markWord mrk, const Klass* kls) {
202   size_t sz = base_size_given_klass(mrk, kls);
203   if (UseCompactObjectHeaders) {
204     assert(!mrk.has_displaced_mark_helper(), "must not be displaced");
205     if (mrk.is_expanded() && kls->expand_for_hash(cast_to_oop(this))) {
206       sz = align_object_size(sz + 1);
207     }
208   }
209   return sz;
210 }
211 
212 size_t oopDesc::copy_size(size_t size, markWord mark) const {
213   if (UseCompactObjectHeaders) {
214     assert(!mark.has_displaced_mark_helper(), "must not be displaced");
215     Klass* klass = mark.klass();
216     if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this))) {
217       size = align_object_size(size + 1);
218     }
219   }
220   assert(is_object_aligned(size), "Oop size is not properly aligned: " SIZE_FORMAT, size);
221   return size;
222 }
223 
224 size_t oopDesc::copy_size_cds(size_t size, markWord mark) const {
225   if (UseCompactObjectHeaders) {
226     assert(!mark.has_displaced_mark_helper(), "must not be displaced");
227     Klass* klass = mark.klass();
228     if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this))) {
229       size = align_object_size(size + 1);
230     }
231     if (mark.is_not_hashed_expanded() && klass->expand_for_hash(cast_to_oop(this))) {
232       size = align_object_size(size - ObjectAlignmentInBytes / HeapWordSize);
233     }
234   }
235   assert(is_object_aligned(size), "Oop size is not properly aligned: " SIZE_FORMAT, size);
236   return size;
237 }
238 
239 size_t oopDesc::size()  {
240   return size_given_mark_and_klass(mark(), klass());
241 }
242 
243 size_t oopDesc::base_size_given_klass(markWord mrk, const Klass* klass)  {
244   int lh = klass->layout_helper();
245   size_t s;
246 
247   // lh is now a value computed at class initialization that may hint
248   // at the size.  For instances, this is positive and equal to the
249   // size.  For arrays, this is negative and provides log2 of the
250   // array element size.  For other oops, it is zero and thus requires
251   // a virtual call.
252   //
253   // We go to all this trouble because the size computation is at the
254   // heart of phase 2 of mark-compaction, and called for every object,
255   // alive or dead.  So the speed here is equal in importance to the
256   // speed of allocation.
257 
258   if (lh > Klass::_lh_neutral_value) {
259     if (!Klass::layout_helper_needs_slow_path(lh)) {
260       s = lh >> LogHeapWordSize;  // deliver size scaled by wordSize
261     } else {
262       s = klass->oop_size(this, mrk);
263     }
264   } else if (lh <= Klass::_lh_neutral_value) {
265     // The most common case is instances; fall through if so.
266     if (lh < Klass::_lh_neutral_value) {
267       // Second most common case is arrays.  We have to fetch the
268       // length of the array, shift (multiply) it appropriately,
269       // up to wordSize, add the header, and align to object size.
270       size_t size_in_bytes;
271       size_t array_length;
272 #ifdef _LP64
273       if (UseCompactObjectHeaders) {
274         array_length = (size_t) mrk.array_length();
275       } else
276 #endif
277         array_length = (size_t)((arrayOop)this)->length();
278 
279       size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
280       size_in_bytes += Klass::layout_helper_header_size(lh);
281 
282       // This code could be simplified, but by keeping array_header_in_bytes
283       // in units of bytes and doing it this way we can round up just once,
284       // skipping the intermediate round to HeapWordSize.
285       s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
286       if (s != klass->oop_size(this, mrk)) {
287         tty->print_cr("length: " SIZE_FORMAT, array_length);
288         tty->print_cr("log element size: %d", Klass::layout_helper_log2_element_size(lh));
289         tty->print_cr("is_objArray: %s", BOOL_TO_STR(klass->is_objArray_klass()));
290       }
291       assert(s == klass->oop_size(this, mrk), "wrong array object size, s: " SIZE_FORMAT ", oop_size: " SIZE_FORMAT, s, klass->oop_size(this, mrk));
292     } else {
293       // Must be zero, so bite the bullet and take the virtual call.
294       s = klass->oop_size(this, mrk);
295     }
296   }
297 
298   assert(s > 0, "Oop size must be greater than zero, not " SIZE_FORMAT, s);
299   assert(is_object_aligned(s), "Oop size is not properly aligned: " SIZE_FORMAT, s);
300   return s;
301 }
302 
303 bool oopDesc::is_instance()    const { return klass()->is_instance_klass();             }
304 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass();   }
305 bool oopDesc::is_stackChunk()  const { return klass()->is_stack_chunk_instance_klass(); }
306 bool oopDesc::is_array()       const { return klass()->is_array_klass();                }
307 bool oopDesc::is_objArray()    const { return klass()->is_objArray_klass();             }
308 bool oopDesc::is_typeArray()   const { return klass()->is_typeArray_klass();            }
309 
310 template<typename T>
311 T*       oopDesc::field_addr(int offset)     const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
312 
313 template <typename T>
314 size_t   oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }

358 
359 bool oopDesc::is_gc_marked() const {
360   return mark().is_marked();
361 }
362 
363 // Used by scavengers
364 bool oopDesc::is_forwarded() const {
365   return mark().is_forwarded();
366 }
367 
368 bool oopDesc::is_self_forwarded() const {
369   return mark().is_self_forwarded();
370 }
371 
372 // Used by scavengers
373 void oopDesc::forward_to(oop p) {
374   assert(cast_from_oop<oopDesc*>(p) != this,
375          "must not be used for self-forwarding, use forward_to_self() instead");
376   markWord m = markWord::encode_pointer_as_mark(p);
377   assert(m.decode_pointer() == p, "encoding must be reversible");
378   set_mark_full(m);
379 }
380 
381 void oopDesc::forward_to_self() {
382   set_mark(mark().set_self_forwarded());
383 }
384 
385 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
386   markWord old_mark = cas_set_mark(new_mark, compare, order);
387   if (old_mark == compare) {
388     return nullptr;
389   } else {
390     assert(old_mark.is_forwarded(), "must be forwarded here");
391     return forwardee(old_mark);
392   }
393 }
394 
395 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
396   assert(cast_from_oop<oopDesc*>(p) != this,
397          "must not be used for self-forwarding, use forward_to_self_atomic() instead");
398   markWord m = markWord::encode_pointer_as_mark(p);

443   if (m.has_displaced_mark_helper()) {
444     m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
445   } else {
446     set_mark(m.incr_age());
447   }
448 }
449 
450 template <typename OopClosureType>
451 void oopDesc::oop_iterate(OopClosureType* cl) {
452   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
453 }
454 
455 template <typename OopClosureType>
456 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
457   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
458 }
459 
460 template <typename OopClosureType>
461 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
462   Klass* k = klass();
463   size_t size = size_given_mark_and_klass(mark(), k);
464   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
465   return size;
466 }
467 
468 template <typename OopClosureType>
469 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
470   Klass* k = klass();
471   size_t size = size_given_mark_and_klass(mark(), k);
472   OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
473   return size;
474 }
475 
476 template <typename OopClosureType>
477 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
478   oop_iterate_backwards(cl, klass());
479 }
480 
481 template <typename OopClosureType>
482 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
483   // In this assert, we cannot safely access the Klass* with compact headers.
484   assert(k == klass(), "wrong klass");
485   OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
486 }
487 
488 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
489   return obj == nullptr || obj->klass()->is_subtype_of(klass);
490 }
491 
492 intptr_t oopDesc::identity_hash() {
493   // Fast case; if the object is unlocked and the hash value is set, no locking is needed
494   // Note: The mark must be read into local variable to avoid concurrent updates.
495   if (UseCompactObjectHeaders) {
496     markWord mrk = mark();
497     if (mrk.is_hashed_expanded()) {
498       Klass* klass = mrk.klass();
499       return int_field(klass->hash_offset_in_bytes(cast_to_oop(this)));
500     }
501     // Fall-through to slow-case.
502   } else {
503     markWord mrk = mark();
504     if (mrk.is_unlocked() && !mrk.has_no_hash()) {
505       return mrk.hash();
506     } else if (mrk.is_marked()) {
507       return mrk.hash();
508     }
509     // Fall-through to slow-case.
510   }
511   return slow_identity_hash();
512 }
513 
514 // This checks fast simple case of whether the oop has_no_hash,
515 // to optimize JVMTI table lookup.
516 bool oopDesc::fast_no_hash_check() {
517   markWord mrk = mark_acquire();
518   assert(!mrk.is_marked(), "should never be marked");
519   return (UseCompactObjectHeaders || mrk.is_unlocked()) && mrk.has_no_hash();
520 }
521 
522 bool oopDesc::has_displaced_mark() const {
523   return mark().has_displaced_mark_helper();
524 }
525 
526 markWord oopDesc::displaced_mark() const {
527   return mark().displaced_mark_helper();
528 }
529 
530 void oopDesc::set_displaced_mark(markWord m) {
531   mark().set_displaced_mark_helper(m);
532 }
533 
534 bool oopDesc::mark_must_be_preserved() const {
535   return mark_must_be_preserved(mark());
536 }
537 
538 bool oopDesc::mark_must_be_preserved(markWord m) const {
539   return m.must_be_preserved(this);
540 }
541 
542 inline void oopDesc::initialize_hash_if_necessary(oop obj) {
543   if (!UseCompactObjectHeaders) {
544     return;
545   }
546   markWord m = mark();
547   assert(!m.has_displaced_mark_helper(), "must not be displaced header");
548   assert(!m.is_forwarded(), "must not be forwarded header");
549   if (m.is_hashed_not_expanded()) {
550     initialize_hash_if_necessary(obj, m.klass(), m);
551   }
552 }
553 
554 
555 #endif // SHARE_OOPS_OOP_INLINE_HPP
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