1 /*
2 * Copyright (c) 1997, 2018, 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
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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
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23 */
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 "memory/metaspaceShared.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/markOop.inline.hpp"
36 #include "oops/oop.hpp"
37 #include "runtime/atomic.hpp"
38 #include "runtime/orderAccess.inline.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 markOop oopDesc::mark() const {
47 return HeapAccess<MO_VOLATILE>::load_at(as_oop(), mark_offset_in_bytes());
48 }
49
50 markOop oopDesc::mark_raw() const {
51 return _mark;
52 }
53
54 markOop* oopDesc::mark_addr_raw() const {
55 return (markOop*) &_mark;
56 }
57
58 void oopDesc::set_mark(volatile markOop m) {
59 HeapAccess<MO_VOLATILE>::store_at(as_oop(), mark_offset_in_bytes(), m);
60 }
61
62 void oopDesc::set_mark_raw(volatile markOop m) {
63 _mark = m;
64 }
65
66 void oopDesc::release_set_mark(markOop m) {
67 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
68 }
69
70 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
71 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark);
72 }
73
74 markOop oopDesc::cas_set_mark_raw(markOop new_mark, markOop old_mark) {
75 return Atomic::cmpxchg(new_mark, &_mark, old_mark);
76 }
77
78 void oopDesc::init_mark() {
79 set_mark(markOopDesc::prototype_for_object(this));
80 }
81
82 void oopDesc::init_mark_raw() {
83 set_mark_raw(markOopDesc::prototype_for_object(this));
84 }
85
86 Klass* oopDesc::klass() const {
87 if (UseCompressedClassPointers) {
88 return Klass::decode_klass_not_null(_metadata._compressed_klass);
89 } else {
90 return _metadata._klass;
91 }
92 }
93
94 Klass* oopDesc::klass_or_null() const volatile {
95 if (UseCompressedClassPointers) {
96 return Klass::decode_klass(_metadata._compressed_klass);
97 } else {
98 return _metadata._klass;
99 }
100 }
101
102 Klass* oopDesc::klass_or_null_acquire() const volatile {
103 if (UseCompressedClassPointers) {
104 // Workaround for non-const load_acquire parameter.
105 const volatile narrowKlass* addr = &_metadata._compressed_klass;
106 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
107 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
108 } else {
109 return OrderAccess::load_acquire(&_metadata._klass);
110 }
111 }
112
113 Klass** oopDesc::klass_addr() {
114 // Only used internally and with CMS and will not work with
115 // UseCompressedOops
116 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
117 return (Klass**) &_metadata._klass;
118 }
119
120 narrowKlass* oopDesc::compressed_klass_addr() {
121 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
122 return &_metadata._compressed_klass;
123 }
124
125 #define CHECK_SET_KLASS(k) \
126 do { \
127 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
128 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
129 } while (0)
130
131 void oopDesc::set_klass(Klass* k) {
132 CHECK_SET_KLASS(k);
133 if (UseCompressedClassPointers) {
134 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
135 } else {
136 *klass_addr() = k;
137 }
138 }
139
140 void oopDesc::release_set_klass(Klass* k) {
141 CHECK_SET_KLASS(k);
142 if (UseCompressedClassPointers) {
143 OrderAccess::release_store(compressed_klass_addr(),
144 Klass::encode_klass_not_null(k));
145 } else {
146 OrderAccess::release_store(klass_addr(), k);
147 }
148 }
149
150 #undef CHECK_SET_KLASS
151
152 int oopDesc::klass_gap() const {
153 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
154 }
155
156 void oopDesc::set_klass_gap(int v) {
157 if (UseCompressedClassPointers) {
158 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
159 }
160 }
161
162 void oopDesc::set_klass_to_list_ptr(oop k) {
163 // This is only to be used during GC, for from-space objects, so no
164 // barrier is needed.
165 if (UseCompressedClassPointers) {
166 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
167 } else {
168 _metadata._klass = (Klass*)(address)k;
169 }
170 }
171
172 oop oopDesc::list_ptr_from_klass() {
173 // This is only to be used during GC, for from-space objects.
174 if (UseCompressedClassPointers) {
175 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
176 } else {
177 // Special case for GC
178 return (oop)(address)_metadata._klass;
179 }
180 }
181
182 bool oopDesc::is_a(Klass* k) const {
183 return klass()->is_subtype_of(k);
184 }
185
186 int oopDesc::size() {
187 return size_given_klass(klass());
188 }
189
190 int oopDesc::size_given_klass(Klass* klass) {
191 int lh = klass->layout_helper();
192 int s;
193
194 // lh is now a value computed at class initialization that may hint
195 // at the size. For instances, this is positive and equal to the
196 // size. For arrays, this is negative and provides log2 of the
197 // array element size. For other oops, it is zero and thus requires
198 // a virtual call.
199 //
200 // We go to all this trouble because the size computation is at the
201 // heart of phase 2 of mark-compaction, and called for every object,
202 // alive or dead. So the speed here is equal in importance to the
203 // speed of allocation.
204
205 if (lh > Klass::_lh_neutral_value) {
206 if (!Klass::layout_helper_needs_slow_path(lh)) {
207 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
208 } else {
209 s = klass->oop_size(this);
210 }
211 } else if (lh <= Klass::_lh_neutral_value) {
212 // The most common case is instances; fall through if so.
213 if (lh < Klass::_lh_neutral_value) {
214 // Second most common case is arrays. We have to fetch the
215 // length of the array, shift (multiply) it appropriately,
216 // up to wordSize, add the header, and align to object size.
217 size_t size_in_bytes;
218 size_t array_length = (size_t) ((arrayOop)this)->length();
219 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
220 size_in_bytes += Klass::layout_helper_header_size(lh);
221
222 // This code could be simplified, but by keeping array_header_in_bytes
223 // in units of bytes and doing it this way we can round up just once,
224 // skipping the intermediate round to HeapWordSize.
225 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
226
227 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
228 // of an "old copy" of an object array in the young gen so it indicates
229 // the grey portion of an already copied array. This will cause the first
230 // disjunct below to fail if the two comparands are computed across such
231 // a concurrent change.
232 // ParNew also runs with promotion labs (which look like int
233 // filler arrays) which are subject to changing their declared size
234 // when finally retiring a PLAB; this also can cause the first disjunct
235 // to fail for another worker thread that is concurrently walking the block
236 // offset table. Both these invariant failures are benign for their
237 // current uses; we relax the assertion checking to cover these two cases below:
238 // is_objArray() && is_forwarded() // covers first scenario above
239 // || is_typeArray() // covers second scenario above
240 // If and when UseParallelGC uses the same obj array oop stealing/chunking
241 // technique, we will need to suitably modify the assertion.
242 assert((s == klass->oop_size(this)) ||
243 (Universe::heap()->is_gc_active() &&
244 ((is_typeArray() && UseConcMarkSweepGC) ||
245 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
246 "wrong array object size");
247 } else {
248 // Must be zero, so bite the bullet and take the virtual call.
249 s = klass->oop_size(this);
250 }
251 }
252
253 assert(s > 0, "Oop size must be greater than zero, not %d", s);
254 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
255 return s;
256 }
257
258 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
259 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
260 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
261 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
262
263 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
264 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
265
266 template <class T>
267 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
268
269 template <typename T>
270 size_t oopDesc::field_offset(T* p) const { return pointer_delta((void*)p, (void*)this, 1); }
271
272 template <DecoratorSet decorators>
273 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
274 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
275
276 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
277
278 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
279 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
280
281 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
282 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
283
284 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
285 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
286
287 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
288 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
289
290 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
291 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
292
293 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
294 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
295
296 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
297 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
298
299 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
300 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
301
302 bool oopDesc::is_locked() const {
303 return mark()->is_locked();
304 }
305
306 bool oopDesc::is_unlocked() const {
307 return mark()->is_unlocked();
308 }
309
310 bool oopDesc::has_bias_pattern() const {
311 return mark()->has_bias_pattern();
312 }
313
314 bool oopDesc::has_bias_pattern_raw() const {
315 return mark_raw()->has_bias_pattern();
316 }
317
318 // Used only for markSweep, scavenging
319 bool oopDesc::is_gc_marked() const {
320 return mark_raw()->is_marked();
321 }
322
323 // Used by scavengers
324 bool oopDesc::is_forwarded() const {
325 // The extra heap check is needed since the obj might be locked, in which case the
326 // mark would point to a stack location and have the sentinel bit cleared
327 return mark_raw()->is_marked();
328 }
329
330 // Used by scavengers
331 void oopDesc::forward_to(oop p) {
332 assert(check_obj_alignment(p),
333 "forwarding to something not aligned");
334 assert(Universe::heap()->is_in_reserved(p),
335 "forwarding to something not in heap");
336 assert(!MetaspaceShared::is_archive_object(oop(this)) &&
337 !MetaspaceShared::is_archive_object(p),
338 "forwarding archive object");
339 markOop m = markOopDesc::encode_pointer_as_mark(p);
340 assert(m->decode_pointer() == p, "encoding must be reversable");
341 set_mark_raw(m);
342 }
343
344 // Used by parallel scavengers
345 bool oopDesc::cas_forward_to(oop p, markOop compare) {
346 assert(check_obj_alignment(p),
347 "forwarding to something not aligned");
348 assert(Universe::heap()->is_in_reserved(p),
349 "forwarding to something not in heap");
350 markOop m = markOopDesc::encode_pointer_as_mark(p);
351 assert(m->decode_pointer() == p, "encoding must be reversable");
352 return cas_set_mark_raw(m, compare) == compare;
353 }
354
355 oop oopDesc::forward_to_atomic(oop p) {
356 markOop oldMark = mark_raw();
357 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
358 markOop curMark;
359
360 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
361 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
362
363 while (!oldMark->is_marked()) {
364 curMark = cas_set_mark_raw(forwardPtrMark, oldMark);
365 assert(is_forwarded(), "object should have been forwarded");
366 if (curMark == oldMark) {
367 return NULL;
368 }
369 // If the CAS was unsuccessful then curMark->is_marked()
370 // should return true as another thread has CAS'd in another
371 // forwarding pointer.
372 oldMark = curMark;
373 }
374 return forwardee();
375 }
376
377 // Note that the forwardee is not the same thing as the displaced_mark.
378 // The forwardee is used when copying during scavenge and mark-sweep.
379 // It does need to clear the low two locking- and GC-related bits.
380 oop oopDesc::forwardee() const {
381 return (oop) mark_raw()->decode_pointer();
382 }
383
384 // The following method needs to be MT safe.
385 uint oopDesc::age() const {
386 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
387 if (has_displaced_mark_raw()) {
388 return displaced_mark_raw()->age();
389 } else {
390 return mark_raw()->age();
391 }
392 }
393
394 void oopDesc::incr_age() {
395 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
396 if (has_displaced_mark_raw()) {
397 set_displaced_mark_raw(displaced_mark_raw()->incr_age());
398 } else {
399 set_mark_raw(mark_raw()->incr_age());
400 }
401 }
402
403 #if INCLUDE_PARALLELGC
404 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
405 klass()->oop_pc_follow_contents(this, cm);
406 }
407
408 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
409 Klass* k = klass();
410 if (!k->is_typeArray_klass()) {
411 // It might contain oops beyond the header, so take the virtual call.
412 k->oop_pc_update_pointers(this, cm);
413 }
414 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
415 }
416
417 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
418 Klass* k = klass();
419 if (!k->is_typeArray_klass()) {
420 // It might contain oops beyond the header, so take the virtual call.
421 k->oop_ps_push_contents(this, pm);
422 }
423 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
424 }
425 #endif // INCLUDE_PARALLELGC
426
427 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
428 \
429 void oopDesc::oop_iterate(OopClosureType* blk) { \
430 klass()->oop_oop_iterate##nv_suffix(this, blk); \
431 } \
432 \
433 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \
434 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
435 }
436
437 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
438 \
439 int oopDesc::oop_iterate_size(OopClosureType* blk) { \
440 Klass* k = klass(); \
441 int size = size_given_klass(k); \
442 k->oop_oop_iterate##nv_suffix(this, blk); \
443 return size; \
444 } \
445 \
446 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \
447 Klass* k = klass(); \
448 int size = size_given_klass(k); \
449 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
450 return size; \
451 }
452
453 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
454 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
455 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
456 NoHeaderExtendedOopClosure cl(blk);
457 return oop_iterate_size(&cl);
458 }
459
460 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
461 NoHeaderExtendedOopClosure cl(blk);
462 return oop_iterate_size(&cl, mr);
463 }
464
465 #if INCLUDE_OOP_OOP_ITERATE_BACKWARDS
466 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
467 \
468 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \
469 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \
470 }
471 #else
472 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
473 #endif
474
475 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \
476 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
477 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
478 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
479
480 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
481 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
482
483 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
484 return obj == NULL || obj->klass()->is_subtype_of(klass);
485 }
486
487 intptr_t oopDesc::identity_hash() {
488 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
489 // Note: The mark must be read into local variable to avoid concurrent updates.
490 markOop mrk = mark();
491 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
492 return mrk->hash();
493 } else if (mrk->is_marked()) {
494 return mrk->hash();
495 } else {
496 return slow_identity_hash();
497 }
498 }
499
500 bool oopDesc::has_displaced_mark_raw() const {
501 return mark_raw()->has_displaced_mark_helper();
502 }
503
504 markOop oopDesc::displaced_mark_raw() const {
505 return mark_raw()->displaced_mark_helper();
506 }
507
508 void oopDesc::set_displaced_mark_raw(markOop m) {
509 mark_raw()->set_displaced_mark_helper(m);
510 }
511
512 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP