1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_VM_OOPS_OOP_INLINE_HPP
26 #define SHARE_VM_OOPS_OOP_INLINE_HPP
27
28 #include "gc/shared/collectedHeap.hpp"
29 #include "oops/access.inline.hpp"
30 #include "oops/arrayKlass.hpp"
31 #include "oops/arrayOop.hpp"
32 #include "oops/compressedOops.inline.hpp"
33 #include "oops/klass.inline.hpp"
34 #include "oops/markOop.inline.hpp"
35 #include "oops/oop.hpp"
36 #include "runtime/atomic.hpp"
37 #include "runtime/orderAccess.hpp"
38 #include "runtime/os.hpp"
39 #include "utilities/align.hpp"
40 #include "utilities/macros.hpp"
41
42 // Implementation of all inlined member functions defined in oop.hpp
43 // We need a separate file to avoid circular references
44
45 markOop oopDesc::mark() const {
46 return HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes());
47 }
48
49 markOop oopDesc::mark_raw() const {
50 return _mark;
51 }
52
53 markOop* oopDesc::mark_addr_raw() const {
54 return (markOop*) &_mark;
55 }
56
57 void oopDesc::set_mark(volatile markOop m) {
58 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m);
59 }
60
61 void oopDesc::set_mark_raw(volatile markOop m) {
62 _mark = m;
63 }
64
65 void oopDesc::set_mark_raw(HeapWord* mem, markOop m) {
66 *(markOop*)(((char*)mem) + mark_offset_in_bytes()) = m;
67 }
68
69 void oopDesc::release_set_mark(markOop m) {
70 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
71 }
72
73 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
74 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark);
75 }
76
77 markOop oopDesc::cas_set_mark_raw(markOop new_mark, markOop old_mark, atomic_memory_order order) {
78 return Atomic::cmpxchg(new_mark, &_mark, old_mark, order);
79 }
80
81 void oopDesc::init_mark() {
82 set_mark(markOopDesc::prototype_for_object(this));
83 }
84
85 void oopDesc::init_mark_raw() {
86 set_mark_raw(markOopDesc::prototype_for_object(this));
87 }
88
89 Klass* oopDesc::klass() const {
90 if (UseCompressedClassPointers) {
91 return Klass::decode_klass_not_null(_metadata._compressed_klass);
92 } else {
93 return _metadata._klass;
94 }
95 }
96
97 Klass* oopDesc::klass_or_null() const volatile {
98 if (UseCompressedClassPointers) {
99 return Klass::decode_klass(_metadata._compressed_klass);
100 } else {
101 return _metadata._klass;
102 }
103 }
104
105 Klass* oopDesc::klass_or_null_acquire() const volatile {
106 if (UseCompressedClassPointers) {
107 // Workaround for non-const load_acquire parameter.
108 const volatile narrowKlass* addr = &_metadata._compressed_klass;
109 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
110 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
111 } else {
112 return OrderAccess::load_acquire(&_metadata._klass);
113 }
114 }
115
116 Klass** oopDesc::klass_addr(HeapWord* mem) {
117 // Only used internally and with CMS and will not work with
118 // UseCompressedOops
119 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
120 ByteSize offset = byte_offset_of(oopDesc, _metadata._klass);
121 return (Klass**) (((char*)mem) + in_bytes(offset));
122 }
123
124 narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) {
125 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
126 ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass);
127 return (narrowKlass*) (((char*)mem) + in_bytes(offset));
128 }
129
130 Klass** oopDesc::klass_addr() {
131 return klass_addr((HeapWord*)this);
132 }
133
134 narrowKlass* oopDesc::compressed_klass_addr() {
135 return compressed_klass_addr((HeapWord*)this);
136 }
137
138 #define CHECK_SET_KLASS(k) \
139 do { \
140 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
141 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
142 } while (0)
143
144 void oopDesc::set_klass(Klass* k) {
145 CHECK_SET_KLASS(k);
146 if (UseCompressedClassPointers) {
147 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
148 } else {
149 *klass_addr() = k;
150 }
151 }
152
153 void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) {
154 CHECK_SET_KLASS(klass);
155 if (UseCompressedClassPointers) {
156 OrderAccess::release_store(compressed_klass_addr(mem),
157 Klass::encode_klass_not_null(klass));
158 } else {
159 OrderAccess::release_store(klass_addr(mem), klass);
160 }
161 }
162
163 #undef CHECK_SET_KLASS
164
165 int oopDesc::klass_gap() const {
166 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
167 }
168
169 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
170 if (UseCompressedClassPointers) {
171 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
172 }
173 }
174
175 void oopDesc::set_klass_gap(int v) {
176 set_klass_gap((HeapWord*)this, v);
177 }
178
179 void oopDesc::set_klass_to_list_ptr(oop k) {
180 // This is only to be used during GC, for from-space objects, so no
181 // barrier is needed.
182 if (UseCompressedClassPointers) {
183 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
184 } else {
185 _metadata._klass = (Klass*)(address)k;
186 }
187 }
188
189 oop oopDesc::list_ptr_from_klass() {
190 // This is only to be used during GC, for from-space objects.
191 if (UseCompressedClassPointers) {
192 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
193 } else {
194 // Special case for GC
195 return (oop)(address)_metadata._klass;
196 }
197 }
198
199 bool oopDesc::is_a(Klass* k) const {
200 return klass()->is_subtype_of(k);
201 }
202
203 int oopDesc::size() {
204 return size_given_klass(klass());
205 }
206
207 int oopDesc::size_given_klass(Klass* klass) {
208 int lh = klass->layout_helper();
209 int s;
210
211 // lh is now a value computed at class initialization that may hint
212 // at the size. For instances, this is positive and equal to the
213 // size. For arrays, this is negative and provides log2 of the
214 // array element size. For other oops, it is zero and thus requires
215 // a virtual call.
216 //
217 // We go to all this trouble because the size computation is at the
218 // heart of phase 2 of mark-compaction, and called for every object,
219 // alive or dead. So the speed here is equal in importance to the
220 // speed of allocation.
221
222 if (lh > Klass::_lh_neutral_value) {
223 if (!Klass::layout_helper_needs_slow_path(lh)) {
224 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
225 } else {
226 s = klass->oop_size(this);
227 }
228 } else if (lh <= Klass::_lh_neutral_value) {
229 // The most common case is instances; fall through if so.
230 if (lh < Klass::_lh_neutral_value) {
231 // Second most common case is arrays. We have to fetch the
232 // length of the array, shift (multiply) it appropriately,
233 // up to wordSize, add the header, and align to object size.
234 size_t size_in_bytes;
235 size_t array_length = (size_t) ((arrayOop)this)->length();
236 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
237 size_in_bytes += Klass::layout_helper_header_size(lh);
238
239 // This code could be simplified, but by keeping array_header_in_bytes
240 // in units of bytes and doing it this way we can round up just once,
241 // skipping the intermediate round to HeapWordSize.
242 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
243
244 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
245 // of an "old copy" of an object array in the young gen so it indicates
246 // the grey portion of an already copied array. This will cause the first
247 // disjunct below to fail if the two comparands are computed across such
248 // a concurrent change.
249 // ParNew also runs with promotion labs (which look like int
250 // filler arrays) which are subject to changing their declared size
251 // when finally retiring a PLAB; this also can cause the first disjunct
252 // to fail for another worker thread that is concurrently walking the block
253 // offset table. Both these invariant failures are benign for their
254 // current uses; we relax the assertion checking to cover these two cases below:
255 // is_objArray() && is_forwarded() // covers first scenario above
256 // || is_typeArray() // covers second scenario above
257 // If and when UseParallelGC uses the same obj array oop stealing/chunking
258 // technique, we will need to suitably modify the assertion.
259 assert((s == klass->oop_size(this)) ||
260 (Universe::heap()->is_gc_active() &&
261 ((is_typeArray() && UseConcMarkSweepGC) ||
262 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
263 "wrong array object size");
264 } else {
265 // Must be zero, so bite the bullet and take the virtual call.
266 s = klass->oop_size(this);
267 }
268 }
269
270 assert(s > 0, "Oop size must be greater than zero, not %d", s);
271 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
272 return s;
273 }
274
275 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
276 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
277 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
278 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
279
280 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
281 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
282
283 template <class T>
284 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
285
286 template <typename T>
287 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
288
289 template <DecoratorSet decorators>
290 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
291 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
292
293 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
294
295 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
296 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
297
298 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
299 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
300
301 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
302 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
303
304 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
305 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
306
307 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
308 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
309 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
310
311 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
312 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
313
314 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
315 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
316
317 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
318 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
319
320 bool oopDesc::is_locked() const {
321 return mark()->is_locked();
322 }
323
324 bool oopDesc::is_unlocked() const {
325 return mark()->is_unlocked();
326 }
327
328 bool oopDesc::has_bias_pattern() const {
329 return mark()->has_bias_pattern();
330 }
331
332 bool oopDesc::has_bias_pattern_raw() const {
333 return mark_raw()->has_bias_pattern();
334 }
335
336 // Used only for markSweep, scavenging
337 bool oopDesc::is_gc_marked() const {
338 return mark_raw()->is_marked();
339 }
340
341 // Used by scavengers
342 bool oopDesc::is_forwarded() const {
343 // The extra heap check is needed since the obj might be locked, in which case the
344 // mark would point to a stack location and have the sentinel bit cleared
345 return mark_raw()->is_marked();
346 }
347
348 // Used by scavengers
349 void oopDesc::forward_to(oop p) {
350 assert(check_obj_alignment(p),
351 "forwarding to something not aligned");
352 assert(Universe::heap()->is_in_reserved(p),
353 "forwarding to something not in heap");
354 assert(!is_archived_object(oop(this)) &&
355 !is_archived_object(p),
356 "forwarding archive object");
357 markOop m = markOopDesc::encode_pointer_as_mark(p);
358 assert(m->decode_pointer() == p, "encoding must be reversable");
359 set_mark_raw(m);
360 }
361
362 // Used by parallel scavengers
363 bool oopDesc::cas_forward_to(oop p, markOop compare, atomic_memory_order order) {
364 assert(check_obj_alignment(p),
365 "forwarding to something not aligned");
366 assert(Universe::heap()->is_in_reserved(p),
367 "forwarding to something not in heap");
368 markOop m = markOopDesc::encode_pointer_as_mark(p);
369 assert(m->decode_pointer() == p, "encoding must be reversable");
370 return cas_set_mark_raw(m, compare, order) == compare;
371 }
372
373 oop oopDesc::forward_to_atomic(oop p, markOop compare, atomic_memory_order order) {
374 // CMS forwards some non-heap value into the mark oop to reserve oops during
375 // promotion, so the next two asserts do not hold.
376 assert(UseConcMarkSweepGC || check_obj_alignment(p),
377 "forwarding to something not aligned");
378 assert(UseConcMarkSweepGC || Universe::heap()->is_in_reserved(p),
379 "forwarding to something not in heap");
380 markOop m = markOopDesc::encode_pointer_as_mark(p);
381 assert(m->decode_pointer() == p, "encoding must be reversable");
382 markOop old_mark = cas_set_mark_raw(m, compare, order);
383 if (old_mark == compare) {
384 return NULL;
385 } else {
386 return (oop)old_mark->decode_pointer();
387 }
388 }
389
390 // Note that the forwardee is not the same thing as the displaced_mark.
391 // The forwardee is used when copying during scavenge and mark-sweep.
392 // It does need to clear the low two locking- and GC-related bits.
393 oop oopDesc::forwardee() const {
394 return (oop) mark_raw()->decode_pointer();
395 }
396
397 // Note that the forwardee is not the same thing as the displaced_mark.
398 // The forwardee is used when copying during scavenge and mark-sweep.
399 // It does need to clear the low two locking- and GC-related bits.
400 oop oopDesc::forwardee_acquire() const {
401 markOop m = OrderAccess::load_acquire(&_mark);
402 return (oop) m->decode_pointer();
403 }
404
405 // The following method needs to be MT safe.
406 uint oopDesc::age() const {
407 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
408 if (has_displaced_mark_raw()) {
409 return displaced_mark_raw()->age();
410 } else {
411 return mark_raw()->age();
412 }
413 }
414
415 void oopDesc::incr_age() {
416 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
417 if (has_displaced_mark_raw()) {
418 set_displaced_mark_raw(displaced_mark_raw()->incr_age());
419 } else {
420 set_mark_raw(mark_raw()->incr_age());
421 }
422 }
423
424 template <typename OopClosureType>
425 void oopDesc::oop_iterate(OopClosureType* cl) {
426 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
427 }
428
429 template <typename OopClosureType>
430 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
431 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
432 }
433
434 template <typename OopClosureType>
435 int oopDesc::oop_iterate_size(OopClosureType* cl) {
436 Klass* k = klass();
437 int size = size_given_klass(k);
438 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
439 return size;
440 }
441
442 template <typename OopClosureType>
443 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
444 Klass* k = klass();
445 int size = size_given_klass(k);
446 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
447 return size;
448 }
449
450 template <typename OopClosureType>
451 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
452 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass());
453 }
454
455 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
456 return obj == NULL || obj->klass()->is_subtype_of(klass);
457 }
458
459 intptr_t oopDesc::identity_hash() {
460 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
461 // Note: The mark must be read into local variable to avoid concurrent updates.
462 markOop mrk = mark();
463 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
464 return mrk->hash();
465 } else if (mrk->is_marked()) {
466 return mrk->hash();
467 } else {
468 return slow_identity_hash();
469 }
470 }
471
472 bool oopDesc::has_displaced_mark_raw() const {
473 return mark_raw()->has_displaced_mark_helper();
474 }
475
476 markOop oopDesc::displaced_mark_raw() const {
477 return mark_raw()->displaced_mark_helper();
478 }
479
480 void oopDesc::set_displaced_mark_raw(markOop m) {
481 mark_raw()->set_displaced_mark_helper(m);
482 }
483
484 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP