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
6 * under the terms of the GNU General Public License version 2 only, as
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
16 * 2 along with this work; if not, write to the Free Software Foundation,
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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 "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.inline.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::release_set_mark(markOop m) {
66 HeapAccess<MO_RELEASE>::store_at(as_oop(), mark_offset_in_bytes(), m);
67 }
68
69 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
70 return HeapAccess<>::atomic_cmpxchg_at(new_mark, as_oop(), mark_offset_in_bytes(), old_mark);
71 }
72
73 markOop oopDesc::cas_set_mark_raw(markOop new_mark, markOop old_mark) {
74 return Atomic::cmpxchg(new_mark, &_mark, old_mark);
75 }
76
77 void oopDesc::init_mark() {
78 set_mark(markOopDesc::prototype_for_object(this));
79 }
80
81 void oopDesc::init_mark_raw() {
82 set_mark_raw(markOopDesc::prototype_for_object(this));
83 }
84
85 Klass* oopDesc::klass() const {
86 if (UseCompressedClassPointers) {
87 return Klass::decode_klass_not_null(_metadata._compressed_klass);
88 } else {
89 return _metadata._klass;
90 }
91 }
92
93 Klass* oopDesc::klass_or_null() const volatile {
94 if (UseCompressedClassPointers) {
95 return Klass::decode_klass(_metadata._compressed_klass);
96 } else {
97 return _metadata._klass;
98 }
99 }
100
101 Klass* oopDesc::klass_or_null_acquire() const volatile {
102 if (UseCompressedClassPointers) {
103 // Workaround for non-const load_acquire parameter.
104 const volatile narrowKlass* addr = &_metadata._compressed_klass;
105 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
106 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
107 } else {
108 return OrderAccess::load_acquire(&_metadata._klass);
109 }
110 }
111
112 Klass** oopDesc::klass_addr() {
113 // Only used internally and with CMS and will not work with
114 // UseCompressedOops
115 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
116 return (Klass**) &_metadata._klass;
117 }
118
119 narrowKlass* oopDesc::compressed_klass_addr() {
120 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
121 return &_metadata._compressed_klass;
122 }
123
124 #define CHECK_SET_KLASS(k) \
125 do { \
126 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
127 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
128 } while (0)
129
130 void oopDesc::set_klass(Klass* k) {
131 CHECK_SET_KLASS(k);
132 if (UseCompressedClassPointers) {
133 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
134 } else {
135 *klass_addr() = k;
136 }
137 }
138
139 void oopDesc::release_set_klass(Klass* k) {
140 CHECK_SET_KLASS(k);
141 if (UseCompressedClassPointers) {
142 OrderAccess::release_store(compressed_klass_addr(),
143 Klass::encode_klass_not_null(k));
144 } else {
145 OrderAccess::release_store(klass_addr(), k);
146 }
147 }
148
149 #undef CHECK_SET_KLASS
150
151 int oopDesc::klass_gap() const {
152 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
153 }
154
155 void oopDesc::set_klass_gap(int v) {
156 if (UseCompressedClassPointers) {
157 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
158 }
159 }
160
161 void oopDesc::set_klass_to_list_ptr(oop k) {
162 // This is only to be used during GC, for from-space objects, so no
163 // barrier is needed.
164 if (UseCompressedClassPointers) {
165 _metadata._compressed_klass = (narrowKlass)CompressedOops::encode(k); // may be null (parnew overflow handling)
166 } else {
167 _metadata._klass = (Klass*)(address)k;
168 }
169 }
170
171 oop oopDesc::list_ptr_from_klass() {
172 // This is only to be used during GC, for from-space objects.
173 if (UseCompressedClassPointers) {
174 return CompressedOops::decode((narrowOop)_metadata._compressed_klass);
175 } else {
176 // Special case for GC
177 return (oop)(address)_metadata._klass;
178 }
179 }
180
181 bool oopDesc::is_a(Klass* k) const {
182 return klass()->is_subtype_of(k);
183 }
184
185 int oopDesc::size() {
186 return size_given_klass(klass());
187 }
188
189 int oopDesc::size_given_klass(Klass* klass) {
190 int lh = klass->layout_helper();
191 int s;
192
193 // lh is now a value computed at class initialization that may hint
194 // at the size. For instances, this is positive and equal to the
195 // size. For arrays, this is negative and provides log2 of the
196 // array element size. For other oops, it is zero and thus requires
197 // a virtual call.
198 //
199 // We go to all this trouble because the size computation is at the
200 // heart of phase 2 of mark-compaction, and called for every object,
201 // alive or dead. So the speed here is equal in importance to the
202 // speed of allocation.
203
204 if (lh > Klass::_lh_neutral_value) {
205 if (!Klass::layout_helper_needs_slow_path(lh)) {
206 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
207 } else {
208 s = klass->oop_size(this);
209 }
210 } else if (lh <= Klass::_lh_neutral_value) {
211 // The most common case is instances; fall through if so.
212 if (lh < Klass::_lh_neutral_value) {
213 // Second most common case is arrays. We have to fetch the
214 // length of the array, shift (multiply) it appropriately,
215 // up to wordSize, add the header, and align to object size.
216 size_t size_in_bytes;
217 size_t array_length = (size_t) ((arrayOop)this)->length();
218 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
219 size_in_bytes += Klass::layout_helper_header_size(lh);
220
221 // This code could be simplified, but by keeping array_header_in_bytes
222 // in units of bytes and doing it this way we can round up just once,
223 // skipping the intermediate round to HeapWordSize.
224 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
225
226 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
227 // of an "old copy" of an object array in the young gen so it indicates
228 // the grey portion of an already copied array. This will cause the first
229 // disjunct below to fail if the two comparands are computed across such
230 // a concurrent change.
231 // ParNew also runs with promotion labs (which look like int
232 // filler arrays) which are subject to changing their declared size
233 // when finally retiring a PLAB; this also can cause the first disjunct
234 // to fail for another worker thread that is concurrently walking the block
235 // offset table. Both these invariant failures are benign for their
236 // current uses; we relax the assertion checking to cover these two cases below:
237 // is_objArray() && is_forwarded() // covers first scenario above
238 // || is_typeArray() // covers second scenario above
239 // If and when UseParallelGC uses the same obj array oop stealing/chunking
240 // technique, we will need to suitably modify the assertion.
241 assert((s == klass->oop_size(this)) ||
242 (Universe::heap()->is_gc_active() &&
243 ((is_typeArray() && UseConcMarkSweepGC) ||
244 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
245 "wrong array object size");
246 } else {
247 // Must be zero, so bite the bullet and take the virtual call.
248 s = klass->oop_size(this);
249 }
250 }
251
252 assert(s > 0, "Oop size must be greater than zero, not %d", s);
253 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
254 return s;
255 }
256
257 bool oopDesc::is_instance() const { return klass()->is_instance_klass(); }
258 bool oopDesc::is_array() const { return klass()->is_array_klass(); }
259 bool oopDesc::is_objArray() const { return klass()->is_objArray_klass(); }
260 bool oopDesc::is_typeArray() const { return klass()->is_typeArray_klass(); }
261
262 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
263 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
264
265 template <class T>
266 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
267
268 template <DecoratorSet decorators>
269 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
270 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
271
272 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
273
274 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
275 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
276
277 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
278 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
279
280 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
281 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
282
283 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
284 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
285
286 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
287 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
288
289 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
290 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
291
292 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
293 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
294
295 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
296 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
297
298 bool oopDesc::is_locked() const {
299 return mark()->is_locked();
300 }
301
302 bool oopDesc::is_unlocked() const {
303 return mark()->is_unlocked();
304 }
305
306 bool oopDesc::has_bias_pattern() const {
307 return mark()->has_bias_pattern();
308 }
309
310 bool oopDesc::has_bias_pattern_raw() const {
311 return mark_raw()->has_bias_pattern();
312 }
313
314 // Used only for markSweep, scavenging
315 bool oopDesc::is_gc_marked() const {
316 return mark_raw()->is_marked();
317 }
318
319 // Used by scavengers
320 bool oopDesc::is_forwarded() const {
321 // The extra heap check is needed since the obj might be locked, in which case the
322 // mark would point to a stack location and have the sentinel bit cleared
323 return mark_raw()->is_marked();
324 }
325
326 // Used by scavengers
327 void oopDesc::forward_to(oop p) {
328 assert(check_obj_alignment(p),
329 "forwarding to something not aligned");
330 assert(Universe::heap()->is_in_reserved(p),
331 "forwarding to something not in heap");
332 assert(!is_archive_object(oop(this)) &&
333 !is_archive_object(p),
334 "forwarding archive object");
335 markOop m = markOopDesc::encode_pointer_as_mark(p);
336 assert(m->decode_pointer() == p, "encoding must be reversable");
337 set_mark_raw(m);
338 }
339
340 // Used by parallel scavengers
341 bool oopDesc::cas_forward_to(oop p, markOop compare) {
342 assert(check_obj_alignment(p),
343 "forwarding to something not aligned");
344 assert(Universe::heap()->is_in_reserved(p),
345 "forwarding to something not in heap");
346 markOop m = markOopDesc::encode_pointer_as_mark(p);
347 assert(m->decode_pointer() == p, "encoding must be reversable");
348 return cas_set_mark_raw(m, compare) == compare;
349 }
350
351 #if INCLUDE_ALL_GCS
352 oop oopDesc::forward_to_atomic(oop p) {
353 markOop oldMark = mark_raw();
354 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
355 markOop curMark;
356
357 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
358 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
359
360 while (!oldMark->is_marked()) {
361 curMark = cas_set_mark_raw(forwardPtrMark, oldMark);
362 assert(is_forwarded(), "object should have been forwarded");
363 if (curMark == oldMark) {
364 return NULL;
365 }
366 // If the CAS was unsuccessful then curMark->is_marked()
367 // should return true as another thread has CAS'd in another
368 // forwarding pointer.
369 oldMark = curMark;
370 }
371 return forwardee();
372 }
373 #endif
374
375 // Note that the forwardee is not the same thing as the displaced_mark.
376 // The forwardee is used when copying during scavenge and mark-sweep.
377 // It does need to clear the low two locking- and GC-related bits.
378 oop oopDesc::forwardee() const {
379 return (oop) mark_raw()->decode_pointer();
380 }
381
382 // The following method needs to be MT safe.
383 uint oopDesc::age() const {
384 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
385 if (has_displaced_mark_raw()) {
386 return displaced_mark_raw()->age();
387 } else {
388 return mark_raw()->age();
389 }
390 }
391
392 void oopDesc::incr_age() {
393 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
394 if (has_displaced_mark_raw()) {
395 set_displaced_mark_raw(displaced_mark_raw()->incr_age());
396 } else {
397 set_mark_raw(mark_raw()->incr_age());
398 }
399 }
400
401 #if INCLUDE_ALL_GCS
402 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
403 klass()->oop_pc_follow_contents(this, cm);
404 }
405
406 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
407 Klass* k = klass();
408 if (!k->is_typeArray_klass()) {
409 // It might contain oops beyond the header, so take the virtual call.
410 k->oop_pc_update_pointers(this, cm);
411 }
412 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
413 }
414
415 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
416 Klass* k = klass();
417 if (!k->is_typeArray_klass()) {
418 // It might contain oops beyond the header, so take the virtual call.
419 k->oop_ps_push_contents(this, pm);
420 }
421 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
422 }
423 #endif // INCLUDE_ALL_GCS
424
425 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
426 \
427 void oopDesc::oop_iterate(OopClosureType* blk) { \
428 klass()->oop_oop_iterate##nv_suffix(this, blk); \
429 } \
430 \
431 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \
432 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
433 }
434
435 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
436 \
437 int oopDesc::oop_iterate_size(OopClosureType* blk) { \
438 Klass* k = klass(); \
439 int size = size_given_klass(k); \
440 k->oop_oop_iterate##nv_suffix(this, blk); \
441 return size; \
442 } \
443 \
444 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \
445 Klass* k = klass(); \
446 int size = size_given_klass(k); \
447 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
448 return size; \
449 }
450
451 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
452 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
453 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
454 NoHeaderExtendedOopClosure cl(blk);
455 return oop_iterate_size(&cl);
456 }
457
458 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
459 NoHeaderExtendedOopClosure cl(blk);
460 return oop_iterate_size(&cl, mr);
461 }
462
463 #if INCLUDE_ALL_GCS
464 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
465 \
466 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \
467 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \
468 }
469 #else
470 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
471 #endif // INCLUDE_ALL_GCS
472
473 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \
474 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
475 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
476 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
477
478 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
479 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
480
481 bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
482 return obj == NULL || obj->klass()->is_subtype_of(klass);
483 }
484
485 intptr_t oopDesc::identity_hash() {
486 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
487 // Note: The mark must be read into local variable to avoid concurrent updates.
488 markOop mrk = mark();
489 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
490 return mrk->hash();
491 } else if (mrk->is_marked()) {
492 return mrk->hash();
493 } else {
494 return slow_identity_hash();
495 }
496 }
497
498 bool oopDesc::has_displaced_mark_raw() const {
499 return mark_raw()->has_displaced_mark_helper();
500 }
501
502 markOop oopDesc::displaced_mark_raw() const {
503 return mark_raw()->displaced_mark_helper();
504 }
505
506 void oopDesc::set_displaced_mark_raw(markOop m) {
507 mark_raw()->set_displaced_mark_helper(m);
508 }
509
510 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP