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 AtomicAccess::store(&_mark, m);
63 }
64
65 void oopDesc::set_mark(HeapWord* mem, markWord m) {
66 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(HeapWord* mem, markWord m) {
70 AtomicAccess::release_store((markWord*)(((char*)mem) + mark_offset_in_bytes()), m);
71 }
72
73 void oopDesc::release_set_mark(markWord m) {
74 AtomicAccess::release_store(&_mark, m);
75 }
76
77 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
78 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark);
79 }
80
81 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
82 return AtomicAccess::cmpxchg(&_mark, old_mark, new_mark, order);
83 }
84
85 markWord oopDesc::prototype_mark() const {
86 if (UseCompactObjectHeaders) {
87 return klass()->prototype_header();
88 } else {
89 return markWord::prototype();
90 }
91 }
92
93 void oopDesc::init_mark() {
94 set_mark(prototype_mark());
95 }
96
97 Klass* oopDesc::klass() const {
98 switch (ObjLayout::klass_mode()) {
99 case ObjLayout::Compact:
100 return mark().klass();
101 case ObjLayout::Compressed:
102 return CompressedKlassPointers::decode_not_null(_compressed_klass);
103 default:
104 ShouldNotReachHere();
105 }
106 }
107
108 Klass* oopDesc::klass_or_null() const {
109 switch (ObjLayout::klass_mode()) {
110 case ObjLayout::Compact:
111 return mark().klass_or_null();
112 case ObjLayout::Compressed:
113 return CompressedKlassPointers::decode(_compressed_klass);
114 default:
115 ShouldNotReachHere();
116 }
156 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
157 _compressed_klass = CompressedKlassPointers::encode_not_null(k);
158 }
159
160 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
161 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
162 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
163 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
164 AtomicAccess::release_store((narrowKlass*)raw_mem, CompressedKlassPointers::encode_not_null(k));
165 }
166
167 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
168 assert(has_klass_gap(), "precondition");
169 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
170 }
171
172 bool oopDesc::is_a(Klass* k) const {
173 return klass()->is_subtype_of(k);
174 }
175
176 size_t oopDesc::size() {
177 return size_given_klass(klass());
178 }
179
180 size_t oopDesc::size_given_klass(Klass* klass) {
181 int lh = klass->layout_helper();
182 size_t s;
183
184 // lh is now a value computed at class initialization that may hint
185 // at the size. For instances, this is positive and equal to the
186 // size. For arrays, this is negative and provides log2 of the
187 // array element size. For other oops, it is zero and thus requires
188 // a virtual call.
189 //
190 // We go to all this trouble because the size computation is at the
191 // heart of phase 2 of mark-compaction, and called for every object,
192 // alive or dead. So the speed here is equal in importance to the
193 // speed of allocation.
194
195 if (lh > Klass::_lh_neutral_value) {
196 if (!Klass::layout_helper_needs_slow_path(lh)) {
197 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
198 } else {
199 s = klass->oop_size(this);
200 }
201 } else if (lh <= Klass::_lh_neutral_value) {
202 // The most common case is instances; fall through if so.
203 if (lh < Klass::_lh_neutral_value) {
204 // Second most common case is arrays. We have to fetch the
205 // length of the array, shift (multiply) it appropriately,
206 // up to wordSize, add the header, and align to object size.
207 size_t size_in_bytes;
208 size_t array_length = (size_t) ((arrayOop)this)->length();
209 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
210 size_in_bytes += Klass::layout_helper_header_size(lh);
211
212 // This code could be simplified, but by keeping array_header_in_bytes
213 // in units of bytes and doing it this way we can round up just once,
214 // skipping the intermediate round to HeapWordSize.
215 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
216
217 assert(s == klass->oop_size(this), "wrong array object size");
218 } else {
219 // Must be zero, so bite the bullet and take the virtual call.
220 s = klass->oop_size(this);
221 }
222 }
223
224 assert(s > 0, "Oop size must be greater than zero, not %zu", s);
225 assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
226 return s;
227 }
228
229 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
230 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
231 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
232 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
233 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
234 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
235
236 template<typename T>
237 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
238
239 template <typename T>
240 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
283 }
284
285 bool oopDesc::is_gc_marked() const {
286 return mark().is_marked();
287 }
288
289 // Used by scavengers
290 bool oopDesc::is_forwarded() const {
291 return mark().is_forwarded();
292 }
293
294 bool oopDesc::is_self_forwarded() const {
295 return mark().is_self_forwarded();
296 }
297
298 // Used by scavengers
299 void oopDesc::forward_to(oop p) {
300 assert(cast_from_oop<oopDesc*>(p) != this,
301 "must not be used for self-forwarding, use forward_to_self() instead");
302 markWord m = markWord::encode_pointer_as_mark(p);
303 assert(m.decode_pointer() == p, "encoding must be reversible");
304 set_mark(m);
305 }
306
307 void oopDesc::forward_to_self() {
308 set_mark(mark().set_self_forwarded());
309 }
310
311 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
312 markWord old_mark = cas_set_mark(new_mark, compare, order);
313 if (old_mark == compare) {
314 return nullptr;
315 } else {
316 assert(old_mark.is_forwarded(), "must be forwarded here");
317 return forwardee(old_mark);
318 }
319 }
320
321 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
322 assert(cast_from_oop<oopDesc*>(p) != this,
323 "must not be used for self-forwarding, use forward_to_self_atomic() instead");
324 markWord m = markWord::encode_pointer_as_mark(p);
325 assert(forwardee(m) == p, "encoding must be reversible");
326 return cas_set_forwardee(m, compare, order);
327 }
328
329 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
330 markWord new_mark = old_mark.set_self_forwarded();
331 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
332 return cas_set_forwardee(new_mark, old_mark, order);
333 }
334
335 oop oopDesc::forwardee(markWord mark) const {
336 assert(mark.is_forwarded(), "only decode when actually forwarded");
337 if (mark.is_self_forwarded()) {
338 return cast_to_oop(this);
339 } else {
340 return mark.forwardee();
341 }
342 }
343
344 // Note that the forwardee is not the same thing as the displaced_mark.
369 if (m.has_displaced_mark_helper()) {
370 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
371 } else {
372 set_mark(m.incr_age());
373 }
374 }
375
376 template <typename OopClosureType>
377 void oopDesc::oop_iterate(OopClosureType* cl) {
378 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
379 }
380
381 template <typename OopClosureType>
382 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
383 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
384 }
385
386 template <typename OopClosureType>
387 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
388 Klass* k = klass();
389 size_t size = size_given_klass(k);
390 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
391 return size;
392 }
393
394 template <typename OopClosureType>
395 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
396 Klass* k = klass();
397 size_t size = size_given_klass(k);
398 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
399 return size;
400 }
401
402 template <typename OopClosureType>
403 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
404 oop_iterate_backwards(cl, klass());
405 }
406
407 template <typename OopClosureType>
408 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
409 // In this assert, we cannot safely access the Klass* with compact headers.
410 assert(k == klass(), "wrong klass");
411 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
412 }
413
414 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
415 return obj == nullptr || obj->klass()->is_subtype_of(klass);
416 }
417
418 intptr_t oopDesc::identity_hash() {
419 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
420 // Note: The mark must be read into local variable to avoid concurrent updates.
421 markWord mrk = mark();
422 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
423 return mrk.hash();
424 } else if (mrk.is_marked()) {
425 return mrk.hash();
426 } else {
427 return slow_identity_hash();
428 }
429 }
430
431 // This checks fast simple case of whether the oop has_no_hash,
432 // to optimize JVMTI table lookup.
433 bool oopDesc::fast_no_hash_check() {
434 markWord mrk = mark_acquire();
435 assert(!mrk.is_marked(), "should never be marked");
436 return mrk.is_unlocked() && mrk.has_no_hash();
437 }
438
439 bool oopDesc::has_displaced_mark() const {
440 return mark().has_displaced_mark_helper();
441 }
442
443 markWord oopDesc::displaced_mark() const {
444 return mark().displaced_mark_helper();
445 }
446
447 void oopDesc::set_displaced_mark(markWord m) {
448 mark().set_displaced_mark_helper(m);
449 }
450
451 bool oopDesc::mark_must_be_preserved() const {
452 return mark_must_be_preserved(mark());
453 }
454
455 bool oopDesc::mark_must_be_preserved(markWord m) const {
456 return m.must_be_preserved();
457 }
458
459 #endif // SHARE_OOPS_OOP_INLINE_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 switch (ObjLayout::klass_mode()) {
129 case ObjLayout::Compact:
130 return mark().klass();
131 case ObjLayout::Compressed:
132 return CompressedKlassPointers::decode_not_null(_compressed_klass);
133 default:
134 ShouldNotReachHere();
135 }
136 }
137
138 Klass* oopDesc::klass_or_null() const {
139 switch (ObjLayout::klass_mode()) {
140 case ObjLayout::Compact:
141 return mark().klass_or_null();
142 case ObjLayout::Compressed:
143 return CompressedKlassPointers::decode(_compressed_klass);
144 default:
145 ShouldNotReachHere();
146 }
186 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
187 _compressed_klass = CompressedKlassPointers::encode_not_null(k);
188 }
189
190 void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
191 assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
192 assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
193 char* raw_mem = ((char*)mem + klass_offset_in_bytes());
194 AtomicAccess::release_store((narrowKlass*)raw_mem, CompressedKlassPointers::encode_not_null(k));
195 }
196
197 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
198 assert(has_klass_gap(), "precondition");
199 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
200 }
201
202 bool oopDesc::is_a(Klass* k) const {
203 return klass()->is_subtype_of(k);
204 }
205
206 size_t oopDesc::size_given_mark_and_klass(markWord mrk, const Klass* kls) {
207 size_t sz = base_size_given_klass(mrk, kls);
208 if (UseCompactObjectHeaders) {
209 assert(!mrk.has_displaced_mark_helper(), "must not be displaced");
210 if (mrk.is_expanded() && kls->expand_for_hash(cast_to_oop(this), mrk)) {
211 sz = align_object_size(sz + 1);
212 }
213 }
214 return sz;
215 }
216
217 size_t oopDesc::size_forwarded() {
218 assert(is_forwarded(), "must be forwarded");
219 markWord m = mark();
220 oop fwd = forwardee(m);
221 if (!UseCompactObjectHeaders) {
222 return fwd->size();
223 }
224 markWord fm = fwd->mark();
225 Klass* klass = fm.klass();
226 if (m.is_forward_expanded()) {
227 // Forwardee was expanded during copy but the original was not.
228 // Original must have base size.
229 return fwd->base_size_given_klass(fm, klass);
230 }
231 // Original and copy have same size (whether expanded or not).
232 return fwd->size_given_mark_and_klass(fm, klass);
233 }
234
235 size_t oopDesc::copy_size(size_t size, markWord mark) const {
236 if (UseCompactObjectHeaders) {
237 assert(!mark.has_displaced_mark_helper(), "must not be displaced");
238 Klass* klass = mark.klass();
239 if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
240 size = align_object_size(size + 1);
241 }
242 }
243 assert(is_object_aligned(size), "Oop size is not properly aligned: %zu", size);
244 return size;
245 }
246
247 size_t oopDesc::copy_size_cds(size_t size, markWord mark) const {
248 if (UseCompactObjectHeaders) {
249 assert(!mark.has_displaced_mark_helper(), "must not be displaced");
250 Klass* klass = mark.klass();
251 if (mark.is_not_hashed_expanded()) {
252 assert(klass->expand_for_hash(cast_to_oop(this), mark), "must be?");
253 }
254 if (mark.is_hashed_not_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
255 size = align_object_size(size + 1);
256 }
257 if (mark.is_not_hashed_expanded() && klass->expand_for_hash(cast_to_oop(this), mark)) {
258 size = align_object_size(size - ObjectAlignmentInBytes / HeapWordSize);
259 }
260 }
261 assert(is_object_aligned(size), "Oop size is not properly aligned: %zu", size);
262 return size;
263 }
264
265 size_t oopDesc::size() {
266 return size_given_mark_and_klass(mark(), klass());
267 }
268
269 size_t oopDesc::base_size_given_klass(markWord mrk, const Klass* klass) {
270 int lh = klass->layout_helper();
271 size_t s;
272
273 // lh is now a value computed at class initialization that may hint
274 // at the size. For instances, this is positive and equal to the
275 // size. For arrays, this is negative and provides log2 of the
276 // array element size. For other oops, it is zero and thus requires
277 // a virtual call.
278 //
279 // We go to all this trouble because the size computation is at the
280 // heart of phase 2 of mark-compaction, and called for every object,
281 // alive or dead. So the speed here is equal in importance to the
282 // speed of allocation.
283
284 if (lh > Klass::_lh_neutral_value) {
285 if (!Klass::layout_helper_needs_slow_path(lh)) {
286 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
287 } else {
288 s = klass->oop_size(this, mrk);
289 }
290 } else if (lh <= Klass::_lh_neutral_value) {
291 // The most common case is instances; fall through if so.
292 if (lh < Klass::_lh_neutral_value) {
293 // Second most common case is arrays. We have to fetch the
294 // length of the array, shift (multiply) it appropriately,
295 // up to wordSize, add the header, and align to object size.
296 size_t size_in_bytes;
297 size_t array_length;
298 #ifdef _LP64
299 if (UseCompactObjectHeaders) {
300 array_length = (size_t) mrk.array_length();
301 } else
302 #endif
303 array_length = (size_t)((arrayOop)this)->length();
304
305 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
306 size_in_bytes += Klass::layout_helper_header_size(lh);
307
308 // This code could be simplified, but by keeping array_header_in_bytes
309 // in units of bytes and doing it this way we can round up just once,
310 // skipping the intermediate round to HeapWordSize.
311 s = align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize;
312 if (s != klass->oop_size(this, mrk)) {
313 tty->print_cr("length: %zu", array_length);
314 tty->print_cr("log element size: %d", Klass::layout_helper_log2_element_size(lh));
315 tty->print_cr("is_objArray: %s", BOOL_TO_STR(klass->is_objArray_klass()));
316 }
317 assert(s == klass->oop_size(this, mrk), "wrong array object size, s: %zu, oop_size: %zu", s, klass->oop_size(this, mrk));
318 } else {
319 // Must be zero, so bite the bullet and take the virtual call.
320 s = klass->oop_size(this, mrk);
321 }
322 }
323
324 assert(s > 0, "Oop size must be greater than zero, not %zu", s);
325 assert(is_object_aligned(s), "Oop size is not properly aligned: %zu", s);
326 return s;
327 }
328
329 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
330 bool oopDesc::is_instanceRef() const { return klass()->is_reference_instance_klass(); }
331 bool oopDesc::is_stackChunk() const { return klass()->is_stack_chunk_instance_klass(); }
332 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
333 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
334 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
335
336 template<typename T>
337 T* oopDesc::field_addr(int offset) const { return reinterpret_cast<T*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
338
339 template <typename T>
340 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
383 }
384
385 bool oopDesc::is_gc_marked() const {
386 return mark().is_marked();
387 }
388
389 // Used by scavengers
390 bool oopDesc::is_forwarded() const {
391 return mark().is_forwarded();
392 }
393
394 bool oopDesc::is_self_forwarded() const {
395 return mark().is_self_forwarded();
396 }
397
398 // Used by scavengers
399 void oopDesc::forward_to(oop p) {
400 assert(cast_from_oop<oopDesc*>(p) != this,
401 "must not be used for self-forwarding, use forward_to_self() instead");
402 markWord m = markWord::encode_pointer_as_mark(p);
403 if (UseCompactObjectHeaders && p->mark().is_expanded() && !mark().is_expanded()) {
404 m = m.set_forward_expanded();
405 }
406 assert(m.decode_pointer() == p, "encoding must be reversible");
407 set_mark_full(m);
408 }
409
410 void oopDesc::forward_to_self() {
411 set_mark(mark().set_self_forwarded());
412 }
413
414 void oopDesc::reset_forwarded() {
415 markWord m = mark();
416 if (m.is_self_forwarded()) {
417 unset_self_forwarded();
418 } else if (m.is_forwarded()) {
419 // Restore Klass* and hash-bits in the header,
420 // for correct iteration.
421 markWord fwd_mark = forwardee()->mark();
422 if (m.is_forward_expanded()) {
423 // Un-expand original object.
424 fwd_mark = fwd_mark.set_hashed_not_expanded();
425 }
426 set_mark_full(fwd_mark);
427 }
428 }
429
430 oop oopDesc::cas_set_forwardee(markWord new_mark, markWord compare, atomic_memory_order order) {
431 markWord old_mark = cas_set_mark(new_mark, compare, order);
432 if (old_mark == compare) {
433 return nullptr;
434 } else {
435 assert(old_mark.is_forwarded(), "must be forwarded here");
436 return forwardee(old_mark);
437 }
438 }
439
440 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
441 assert(cast_from_oop<oopDesc*>(p) != this,
442 "must not be used for self-forwarding, use forward_to_self_atomic() instead");
443 markWord m = markWord::encode_pointer_as_mark(p);
444 if (UseCompactObjectHeaders && compare.is_hashed_not_expanded()) {
445 m = m.set_forward_expanded();
446 }
447 assert(forwardee(m) == p, "encoding must be reversible");
448 return cas_set_forwardee(m, compare, order);
449 }
450
451 oop oopDesc::forward_to_self_atomic(markWord old_mark, atomic_memory_order order) {
452 markWord new_mark = old_mark.set_self_forwarded();
453 assert(forwardee(new_mark) == cast_to_oop(this), "encoding must be reversible");
454 return cas_set_forwardee(new_mark, old_mark, order);
455 }
456
457 oop oopDesc::forwardee(markWord mark) const {
458 assert(mark.is_forwarded(), "only decode when actually forwarded");
459 if (mark.is_self_forwarded()) {
460 return cast_to_oop(this);
461 } else {
462 return mark.forwardee();
463 }
464 }
465
466 // Note that the forwardee is not the same thing as the displaced_mark.
491 if (m.has_displaced_mark_helper()) {
492 m.set_displaced_mark_helper(m.displaced_mark_helper().incr_age());
493 } else {
494 set_mark(m.incr_age());
495 }
496 }
497
498 template <typename OopClosureType>
499 void oopDesc::oop_iterate(OopClosureType* cl) {
500 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
501 }
502
503 template <typename OopClosureType>
504 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
505 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
506 }
507
508 template <typename OopClosureType>
509 size_t oopDesc::oop_iterate_size(OopClosureType* cl) {
510 Klass* k = klass();
511 size_t size = size_given_mark_and_klass(mark(), k);
512 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
513 return size;
514 }
515
516 template <typename OopClosureType>
517 size_t oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
518 Klass* k = klass();
519 size_t size = size_given_mark_and_klass(mark(), k);
520 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
521 return size;
522 }
523
524 template <typename OopClosureType>
525 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
526 oop_iterate_backwards(cl, klass());
527 }
528
529 template <typename OopClosureType>
530 void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
531 // In this assert, we cannot safely access the Klass* with compact headers.
532 assert(k == klass(), "wrong klass");
533 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
534 }
535
536 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
537 return obj == nullptr || obj->klass()->is_subtype_of(klass);
538 }
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 if (UseCompactObjectHeaders) {
544 markWord mrk = mark();
545 if (mrk.is_hashed_expanded()) {
546 Klass* klass = mrk.klass();
547 return int_field(klass->hash_offset_in_bytes(cast_to_oop(this), mrk));
548 }
549 // Fall-through to slow-case.
550 } else {
551 markWord mrk = mark();
552 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
553 return mrk.hash();
554 } else if (mrk.is_marked()) {
555 return mrk.hash();
556 }
557 // Fall-through to slow-case.
558 }
559 return slow_identity_hash();
560 }
561
562 // This checks fast simple case of whether the oop has_no_hash,
563 // to optimize JVMTI table lookup.
564 bool oopDesc::fast_no_hash_check() {
565 markWord mrk = mark_acquire();
566 assert(!mrk.is_marked(), "should never be marked");
567 return (UseCompactObjectHeaders || mrk.is_unlocked()) && mrk.has_no_hash();
568 }
569
570 bool oopDesc::has_displaced_mark() const {
571 return mark().has_displaced_mark_helper();
572 }
573
574 markWord oopDesc::displaced_mark() const {
575 return mark().displaced_mark_helper();
576 }
577
578 void oopDesc::set_displaced_mark(markWord m) {
579 mark().set_displaced_mark_helper(m);
580 }
581
582 bool oopDesc::mark_must_be_preserved() const {
583 return mark_must_be_preserved(mark());
584 }
585
586 bool oopDesc::mark_must_be_preserved(markWord m) const {
587 return m.must_be_preserved();
588 }
589
590 inline void oopDesc::initialize_hash_if_necessary(oop obj) {
591 if (!UseCompactObjectHeaders) {
592 return;
593 }
594 markWord m = mark();
595 assert(!m.has_displaced_mark_helper(), "must not be displaced header");
596 if (m.is_hashed_not_expanded()) {
597 set_mark(initialize_hash_if_necessary(obj, m.klass(), m));
598 }
599 }
600
601
602 #endif // SHARE_OOPS_OOP_INLINE_HPP
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