1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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23 */
24
25 #ifndef SHARE_OOPS_OOP_INLINE_HPP
26 #define SHARE_OOPS_OOP_INLINE_HPP
27
28 #include "gc/shared/collectedHeap.hpp"
29 #include "memory/universe.hpp"
30 #include "oops/access.inline.hpp"
31 #include "oops/arrayKlass.hpp"
32 #include "oops/arrayOop.hpp"
33 #include "oops/compressedOops.inline.hpp"
34 #include "oops/klass.inline.hpp"
35 #include "oops/markWord.inline.hpp"
36 #include "oops/oop.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/orderAccess.hpp"
39 #include "runtime/os.hpp"
40 #include "utilities/align.hpp"
41 #include "utilities/macros.hpp"
42
43 // Implementation of all inlined member functions defined in oop.hpp
44 // We need a separate file to avoid circular references
45
46 markWord oopDesc::mark() const {
47 uintptr_t v = HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes());
48 return markWord(v);
49 }
50
51 markWord oopDesc::mark_raw() const {
52 return Atomic::load(&_mark);
53 }
54
55 markWord* oopDesc::mark_addr_raw() const {
56 return (markWord*) &_mark;
57 }
58
59 void oopDesc::set_mark(markWord m) {
60 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
61 }
62
63 void oopDesc::set_mark_raw(markWord m) {
64 Atomic::store(m, &_mark);
65 }
66
67 void oopDesc::set_mark_raw(HeapWord* mem, markWord m) {
68 *(markWord*)(((char*)mem) + mark_offset_in_bytes()) = m;
69 }
70
71 void oopDesc::release_set_mark(markWord m) {
72 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m.value());
73 }
74
75 markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark) {
76 uintptr_t v = HeapAccess<>::atomic_cmpxchg_at(new_mark.value(), as_oop(), mark_offset_in_bytes(), old_mark.value());
77 return markWord(v);
78 }
79
80 markWord oopDesc::cas_set_mark_raw(markWord new_mark, markWord old_mark, atomic_memory_order order) {
81 return Atomic::cmpxchg(new_mark, &_mark, old_mark, order);
82 }
83
84 void oopDesc::init_mark() {
85 set_mark(markWord::prototype_for_klass(klass()));
86 }
87
88 void oopDesc::init_mark_raw() {
89 set_mark_raw(markWord::prototype_for_klass(klass()));
90 }
91
92 Klass* oopDesc::klass() const {
93 if (UseCompressedClassPointers) {
94 return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
95 } else {
96 return _metadata._klass;
97 }
98 }
99
100 Klass* oopDesc::klass_or_null() const volatile {
101 if (UseCompressedClassPointers) {
102 return CompressedKlassPointers::decode(_metadata._compressed_klass);
103 } else {
104 return _metadata._klass;
105 }
106 }
107
108 Klass* oopDesc::klass_or_null_acquire() const volatile {
109 if (UseCompressedClassPointers) {
110 // Workaround for non-const load_acquire parameter.
111 const volatile narrowKlass* addr = &_metadata._compressed_klass;
112 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
113 return CompressedKlassPointers::decode(OrderAccess::load_acquire(xaddr));
114 } else {
115 return OrderAccess::load_acquire(&_metadata._klass);
116 }
117 }
118
119 Klass** oopDesc::klass_addr(HeapWord* mem) {
120 // Only used internally and with CMS and will not work with
121 // UseCompressedOops
122 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
123 ByteSize offset = byte_offset_of(oopDesc, _metadata._klass);
124 return (Klass**) (((char*)mem) + in_bytes(offset));
125 }
126
127 narrowKlass* oopDesc::compressed_klass_addr(HeapWord* mem) {
128 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
129 ByteSize offset = byte_offset_of(oopDesc, _metadata._compressed_klass);
130 return (narrowKlass*) (((char*)mem) + in_bytes(offset));
131 }
132
133 Klass** oopDesc::klass_addr() {
134 return klass_addr((HeapWord*)this);
135 }
136
137 narrowKlass* oopDesc::compressed_klass_addr() {
138 return compressed_klass_addr((HeapWord*)this);
139 }
140
141 #define CHECK_SET_KLASS(k) \
142 do { \
143 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
144 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
145 } while (0)
146
147 void oopDesc::set_klass(Klass* k) {
148 CHECK_SET_KLASS(k);
149 if (UseCompressedClassPointers) {
150 *compressed_klass_addr() = CompressedKlassPointers::encode_not_null(k);
151 } else {
152 *klass_addr() = k;
153 }
154 }
155
156 void oopDesc::release_set_klass(HeapWord* mem, Klass* klass) {
157 CHECK_SET_KLASS(klass);
158 if (UseCompressedClassPointers) {
159 OrderAccess::release_store(compressed_klass_addr(mem),
160 CompressedKlassPointers::encode_not_null(klass));
161 } else {
162 OrderAccess::release_store(klass_addr(mem), klass);
163 }
164 }
165
166 #undef CHECK_SET_KLASS
167
168 int oopDesc::klass_gap() const {
169 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
170 }
171
172 void oopDesc::set_klass_gap(HeapWord* mem, int v) {
173 if (UseCompressedClassPointers) {
174 *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
175 }
176 }
177
178 void oopDesc::set_klass_gap(int v) {
179 set_klass_gap((HeapWord*)this, v);
180 }
181
182 void oopDesc::set_klass_to_list_ptr(oop k) {
183 // This is only to be used during GC, for from-space objects, so no
184 // barrier is needed.
185 if (UseCompressedClassPointers) {
186 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
187 } else {
188 _metadata._klass = (Klass*)(address)k;
189 }
190 }
191
192 oop oopDesc::list_ptr_from_klass() {
193 // This is only to be used during GC, for from-space objects.
194 if (UseCompressedClassPointers) {
195 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
196 } else {
197 // Special case for GC
198 return (oop)(address)_metadata._klass;
199 }
200 }
201
202 bool oopDesc::is_a(Klass* k) const {
203 return klass()->is_subtype_of(k);
204 }
205
206 int oopDesc::size() {
207 return size_given_klass(klass());
208 }
209
210 int oopDesc::size_given_klass(Klass* klass) {
211 int lh = klass->layout_helper();
212 int s;
213
214 // lh is now a value computed at class initialization that may hint
215 // at the size. For instances, this is positive and equal to the
216 // size. For arrays, this is negative and provides log2 of the
217 // array element size. For other oops, it is zero and thus requires
218 // a virtual call.
219 //
220 // We go to all this trouble because the size computation is at the
221 // heart of phase 2 of mark-compaction, and called for every object,
222 // alive or dead. So the speed here is equal in importance to the
223 // speed of allocation.
224
225 if (lh > Klass::_lh_neutral_value) {
226 if (!Klass::layout_helper_needs_slow_path(lh)) {
227 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
228 } else {
229 s = klass->oop_size(this);
230 }
231 } else if (lh <= Klass::_lh_neutral_value) {
232 // The most common case is instances; fall through if so.
233 if (lh < Klass::_lh_neutral_value) {
234 // Second most common case is arrays. We have to fetch the
235 // length of the array, shift (multiply) it appropriately,
236 // up to wordSize, add the header, and align to object size.
237 size_t size_in_bytes;
238 size_t array_length = (size_t) ((arrayOop)this)->length();
239 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
240 size_in_bytes += Klass::layout_helper_header_size(lh);
241
242 // This code could be simplified, but by keeping array_header_in_bytes
243 // in units of bytes and doing it this way we can round up just once,
244 // skipping the intermediate round to HeapWordSize.
245 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
246
247 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
248 // of an "old copy" of an object array in the young gen so it indicates
249 // the grey portion of an already copied array. This will cause the first
250 // disjunct below to fail if the two comparands are computed across such
251 // a concurrent change.
252 // ParNew also runs with promotion labs (which look like int
253 // filler arrays) which are subject to changing their declared size
254 // when finally retiring a PLAB; this also can cause the first disjunct
255 // to fail for another worker thread that is concurrently walking the block
256 // offset table. Both these invariant failures are benign for their
257 // current uses; we relax the assertion checking to cover these two cases below:
258 // is_objArray() && is_forwarded() // covers first scenario above
259 // || is_typeArray() // covers second scenario above
260 // If and when UseParallelGC uses the same obj array oop stealing/chunking
261 // technique, we will need to suitably modify the assertion.
262 assert((s == klass->oop_size(this)) ||
263 (Universe::heap()->is_gc_active() &&
264 ((is_typeArray() && UseConcMarkSweepGC) ||
265 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
266 "wrong array object size");
267 } else {
268 // Must be zero, so bite the bullet and take the virtual call.
269 s = klass->oop_size(this);
270 }
271 }
272
273 assert(s > 0, "Oop size must be greater than zero, not %d", s);
274 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
275 return s;
276 }
277
278 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
279 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
280 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
281 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
282
283 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
284 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
285
286 template <class T>
287 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
288
289 template <typename T>
290 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
291
292 template <DecoratorSet decorators>
293 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
294 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
295
296 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
297
298 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
299 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
300
301 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
302 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
303
304 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
305 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
306 inline jboolean oopDesc::bool_field_volatile(int offset) const { return HeapAccess<MO_SEQ_CST>::load_at(as_oop(), offset); }
307 inline void oopDesc::bool_field_put_volatile(int offset, jboolean value) { HeapAccess<MO_SEQ_CST>::store_at(as_oop(), offset, jboolean(value & 1)); }
308 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
309 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
310
311 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
312 inline jint oopDesc::int_field_raw(int offset) const { return RawAccess<>::load_at(as_oop(), offset); }
313 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
314
315 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
316 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
317
318 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
319 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
320
321 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
322 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
323
324 bool oopDesc::is_locked() const {
325 return mark().is_locked();
326 }
327
328 bool oopDesc::is_unlocked() const {
329 return mark().is_unlocked();
330 }
331
332 bool oopDesc::has_bias_pattern() const {
333 return mark().has_bias_pattern();
334 }
335
336 bool oopDesc::has_bias_pattern_raw() const {
337 return mark_raw().has_bias_pattern();
338 }
339
340 // Used only for markSweep, scavenging
341 bool oopDesc::is_gc_marked() const {
342 return mark_raw().is_marked();
343 }
344
345 // Used by scavengers
346 bool oopDesc::is_forwarded() const {
347 // The extra heap check is needed since the obj might be locked, in which case the
348 // mark would point to a stack location and have the sentinel bit cleared
349 return mark_raw().is_marked();
350 }
351
352 // Used by scavengers
353 void oopDesc::forward_to(oop p) {
354 verify_forwardee(p);
355 markWord m = markWord::encode_pointer_as_mark(p);
356 assert(m.decode_pointer() == p, "encoding must be reversable");
357 set_mark_raw(m);
358 }
359
360 // Used by parallel scavengers
361 bool oopDesc::cas_forward_to(oop p, markWord compare, atomic_memory_order order) {
362 verify_forwardee(p);
363 markWord m = markWord::encode_pointer_as_mark(p);
364 assert(m.decode_pointer() == p, "encoding must be reversable");
365 return cas_set_mark_raw(m, compare, order) == compare;
366 }
367
368 oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
369 verify_forwardee(p);
370 markWord m = markWord::encode_pointer_as_mark(p);
371 assert(m.decode_pointer() == p, "encoding must be reversable");
372 markWord old_mark = cas_set_mark_raw(m, compare, order);
373 if (old_mark == compare) {
374 return NULL;
375 } else {
376 return (oop)old_mark.decode_pointer();
377 }
378 }
379
380 // Note that the forwardee is not the same thing as the displaced_mark.
381 // The forwardee is used when copying during scavenge and mark-sweep.
382 // It does need to clear the low two locking- and GC-related bits.
383 oop oopDesc::forwardee() const {
384 return (oop) mark_raw().decode_pointer();
385 }
386
387 // Note that the forwardee is not the same thing as the displaced_mark.
388 // The forwardee is used when copying during scavenge and mark-sweep.
389 // It does need to clear the low two locking- and GC-related bits.
390 oop oopDesc::forwardee_acquire() const {
391 return (oop) OrderAccess::load_acquire(&_mark).decode_pointer();
392 }
393
394 // The following method needs to be MT safe.
395 uint oopDesc::age() const {
396 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
397 if (has_displaced_mark_raw()) {
398 return displaced_mark_raw().age();
399 } else {
400 return mark_raw().age();
401 }
402 }
403
404 void oopDesc::incr_age() {
405 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
406 if (has_displaced_mark_raw()) {
407 set_displaced_mark_raw(displaced_mark_raw().incr_age());
408 } else {
409 set_mark_raw(mark_raw().incr_age());
410 }
411 }
412
413 template <typename OopClosureType>
414 void oopDesc::oop_iterate(OopClosureType* cl) {
415 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass());
416 }
417
418 template <typename OopClosureType>
419 void oopDesc::oop_iterate(OopClosureType* cl, MemRegion mr) {
420 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, klass(), mr);
421 }
422
423 template <typename OopClosureType>
424 int oopDesc::oop_iterate_size(OopClosureType* cl) {
425 Klass* k = klass();
426 int size = size_given_klass(k);
427 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k);
428 return size;
429 }
430
431 template <typename OopClosureType>
432 int oopDesc::oop_iterate_size(OopClosureType* cl, MemRegion mr) {
433 Klass* k = klass();
434 int size = size_given_klass(k);
435 OopIteratorClosureDispatch::oop_oop_iterate(cl, this, k, mr);
436 return size;
437 }
438
439 template <typename OopClosureType>
440 void oopDesc::oop_iterate_backwards(OopClosureType* cl) {
441 OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, klass());
442 }
443
444 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
445 return obj == NULL || obj->klass()->is_subtype_of(klass);
446 }
447
448 intptr_t oopDesc::identity_hash() {
449 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
450 // Note: The mark must be read into local variable to avoid concurrent updates.
451 markWord mrk = mark();
452 if (mrk.is_unlocked() && !mrk.has_no_hash()) {
453 return mrk.hash();
454 } else if (mrk.is_marked()) {
455 return mrk.hash();
456 } else {
457 return slow_identity_hash();
458 }
459 }
460
461 bool oopDesc::has_displaced_mark_raw() const {
462 return mark_raw().has_displaced_mark_helper();
463 }
464
465 markWord oopDesc::displaced_mark_raw() const {
466 return mark_raw().displaced_mark_helper();
467 }
468
469 void oopDesc::set_displaced_mark_raw(markWord m) {
470 mark_raw().set_displaced_mark_helper(m);
471 }
472
473 // Supports deferred calling of obj->klass().
474 class DeferredObjectToKlass {
475 const oopDesc* _obj;
476
477 public:
478 DeferredObjectToKlass(const oopDesc* obj) : _obj(obj) {}
479
480 // Implicitly convertible to const Klass*.
481 operator const Klass*() const {
482 return _obj->klass();
483 }
484 };
485
486 bool oopDesc::mark_must_be_preserved() const {
487 return mark_must_be_preserved(mark_raw());
488 }
489
490 bool oopDesc::mark_must_be_preserved(markWord m) const {
491 // There's a circular dependency between oop.inline.hpp and
492 // markWord.inline.hpp because markWord::must_be_preserved wants to call
493 // oopDesc::klass(). This could be solved by calling klass() here. However,
494 // not all paths inside must_be_preserved calls klass(). Defer the call until
495 // the klass is actually needed.
496 return m.must_be_preserved(DeferredObjectToKlass(this));
497 }
498
499 bool oopDesc::mark_must_be_preserved_for_promotion_failure(markWord m) const {
500 return m.must_be_preserved_for_promotion_failure(DeferredObjectToKlass(this));
501 }
502
503 #endif // SHARE_OOPS_OOP_INLINE_HPP