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,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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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/ageTable.hpp"
29 #include "gc/shared/collectedHeap.inline.hpp"
30 #include "gc/shared/genCollectedHeap.hpp"
31 #include "gc/shared/generation.hpp"
32 #include "oops/access.inline.hpp"
33 #include "oops/arrayKlass.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/klass.inline.hpp"
36 #include "oops/markOop.inline.hpp"
37 #include "oops/oop.hpp"
38 #include "runtime/atomic.hpp"
39 #include "runtime/orderAccess.inline.hpp"
40 #include "runtime/os.hpp"
41 #include "utilities/align.hpp"
42 #include "utilities/macros.hpp"
43
44 // Implementation of all inlined member functions defined in oop.hpp
45 // We need a separate file to avoid circular references
46
47 void oopDesc::release_set_mark(markOop m) {
48 OrderAccess::release_store(&_mark, m);
49 }
50
51 markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
52 return Atomic::cmpxchg(new_mark, &_mark, old_mark);
53 }
54
55 void oopDesc::init_mark() {
56 set_mark(markOopDesc::prototype_for_object(this));
57 }
58
59 Klass* oopDesc::klass() const {
60 if (UseCompressedClassPointers) {
61 return Klass::decode_klass_not_null(_metadata._compressed_klass);
62 } else {
63 return _metadata._klass;
64 }
65 }
66
67 Klass* oopDesc::klass_or_null() const volatile {
68 if (UseCompressedClassPointers) {
69 return Klass::decode_klass(_metadata._compressed_klass);
70 } else {
71 return _metadata._klass;
72 }
73 }
74
75 Klass* oopDesc::klass_or_null_acquire() const volatile {
76 if (UseCompressedClassPointers) {
77 // Workaround for non-const load_acquire parameter.
78 const volatile narrowKlass* addr = &_metadata._compressed_klass;
79 volatile narrowKlass* xaddr = const_cast<volatile narrowKlass*>(addr);
80 return Klass::decode_klass(OrderAccess::load_acquire(xaddr));
81 } else {
82 return OrderAccess::load_acquire(&_metadata._klass);
83 }
84 }
85
86 Klass** oopDesc::klass_addr() {
87 // Only used internally and with CMS and will not work with
88 // UseCompressedOops
89 assert(!UseCompressedClassPointers, "only supported with uncompressed klass pointers");
90 return (Klass**) &_metadata._klass;
91 }
92
93 narrowKlass* oopDesc::compressed_klass_addr() {
94 assert(UseCompressedClassPointers, "only called by compressed klass pointers");
95 return &_metadata._compressed_klass;
96 }
97
98 #define CHECK_SET_KLASS(k) \
99 do { \
100 assert(Universe::is_bootstrapping() || k != NULL, "NULL Klass"); \
101 assert(Universe::is_bootstrapping() || k->is_klass(), "not a Klass"); \
102 } while (0)
103
104 void oopDesc::set_klass(Klass* k) {
105 CHECK_SET_KLASS(k);
106 if (UseCompressedClassPointers) {
107 *compressed_klass_addr() = Klass::encode_klass_not_null(k);
108 } else {
109 *klass_addr() = k;
110 }
111 }
112
113 void oopDesc::release_set_klass(Klass* k) {
114 CHECK_SET_KLASS(k);
115 if (UseCompressedClassPointers) {
116 OrderAccess::release_store(compressed_klass_addr(),
117 Klass::encode_klass_not_null(k));
118 } else {
119 OrderAccess::release_store(klass_addr(), k);
120 }
121 }
122
123 #undef CHECK_SET_KLASS
124
125 int oopDesc::klass_gap() const {
126 return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
127 }
128
129 void oopDesc::set_klass_gap(int v) {
130 if (UseCompressedClassPointers) {
131 *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
132 }
133 }
134
135 void oopDesc::set_klass_to_list_ptr(oop k) {
136 // This is only to be used during GC, for from-space objects, so no
137 // barrier is needed.
138 if (UseCompressedClassPointers) {
139 _metadata._compressed_klass = (narrowKlass)encode_heap_oop(k); // may be null (parnew overflow handling)
140 } else {
141 _metadata._klass = (Klass*)(address)k;
142 }
143 }
144
145 oop oopDesc::list_ptr_from_klass() {
146 // This is only to be used during GC, for from-space objects.
147 if (UseCompressedClassPointers) {
148 return decode_heap_oop((narrowOop)_metadata._compressed_klass);
149 } else {
150 // Special case for GC
151 return (oop)(address)_metadata._klass;
152 }
153 }
154
155 bool oopDesc::is_a(Klass* k) const {
156 return klass()->is_subtype_of(k);
157 }
158
159 int oopDesc::size() {
160 return size_given_klass(klass());
161 }
162
163 int oopDesc::size_given_klass(Klass* klass) {
164 int lh = klass->layout_helper();
165 int s;
166
167 // lh is now a value computed at class initialization that may hint
168 // at the size. For instances, this is positive and equal to the
169 // size. For arrays, this is negative and provides log2 of the
170 // array element size. For other oops, it is zero and thus requires
171 // a virtual call.
172 //
173 // We go to all this trouble because the size computation is at the
174 // heart of phase 2 of mark-compaction, and called for every object,
175 // alive or dead. So the speed here is equal in importance to the
176 // speed of allocation.
177
178 if (lh > Klass::_lh_neutral_value) {
179 if (!Klass::layout_helper_needs_slow_path(lh)) {
180 s = lh >> LogHeapWordSize; // deliver size scaled by wordSize
181 } else {
182 s = klass->oop_size(this);
183 }
184 } else if (lh <= Klass::_lh_neutral_value) {
185 // The most common case is instances; fall through if so.
186 if (lh < Klass::_lh_neutral_value) {
187 // Second most common case is arrays. We have to fetch the
188 // length of the array, shift (multiply) it appropriately,
189 // up to wordSize, add the header, and align to object size.
190 size_t size_in_bytes;
191 size_t array_length = (size_t) ((arrayOop)this)->length();
192 size_in_bytes = array_length << Klass::layout_helper_log2_element_size(lh);
193 size_in_bytes += Klass::layout_helper_header_size(lh);
194
195 // This code could be simplified, but by keeping array_header_in_bytes
196 // in units of bytes and doing it this way we can round up just once,
197 // skipping the intermediate round to HeapWordSize.
198 s = (int)(align_up(size_in_bytes, MinObjAlignmentInBytes) / HeapWordSize);
199
200 // ParNew (used by CMS), UseParallelGC and UseG1GC can change the length field
201 // of an "old copy" of an object array in the young gen so it indicates
202 // the grey portion of an already copied array. This will cause the first
203 // disjunct below to fail if the two comparands are computed across such
204 // a concurrent change.
205 // ParNew also runs with promotion labs (which look like int
206 // filler arrays) which are subject to changing their declared size
207 // when finally retiring a PLAB; this also can cause the first disjunct
208 // to fail for another worker thread that is concurrently walking the block
209 // offset table. Both these invariant failures are benign for their
210 // current uses; we relax the assertion checking to cover these two cases below:
211 // is_objArray() && is_forwarded() // covers first scenario above
212 // || is_typeArray() // covers second scenario above
213 // If and when UseParallelGC uses the same obj array oop stealing/chunking
214 // technique, we will need to suitably modify the assertion.
215 assert((s == klass->oop_size(this)) ||
216 (Universe::heap()->is_gc_active() &&
217 ((is_typeArray() && UseConcMarkSweepGC) ||
218 (is_objArray() && is_forwarded() && (UseConcMarkSweepGC || UseParallelGC || UseG1GC)))),
219 "wrong array object size");
220 } else {
221 // Must be zero, so bite the bullet and take the virtual call.
222 s = klass->oop_size(this);
223 }
224 }
225
226 assert(s > 0, "Oop size must be greater than zero, not %d", s);
227 assert(is_object_aligned(s), "Oop size is not properly aligned: %d", s);
228 return s;
229 }
230
231 bool oopDesc::is_instance() const { return klass()->is_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 void* oopDesc::field_addr_raw(int offset) const { return reinterpret_cast<void*>(cast_from_oop<intptr_t>(as_oop()) + offset); }
237 void* oopDesc::field_addr(int offset) const { return Access<>::resolve(as_oop())->field_addr_raw(offset); }
238
239 template <class T>
240 T* oopDesc::obj_field_addr_raw(int offset) const { return (T*) field_addr_raw(offset); }
241
242 // Functions for getting and setting oops within instance objects.
243 // If the oops are compressed, the type passed to these overloaded functions
244 // is narrowOop. All functions are overloaded so they can be called by
245 // template functions without conditionals (the compiler instantiates via
246 // the right type and inlines the appopriate code).
247
248 // Algorithm for encoding and decoding oops from 64 bit pointers to 32 bit
249 // offset from the heap base. Saving the check for null can save instructions
250 // in inner GC loops so these are separated.
251
252 inline bool check_obj_alignment(oop obj) {
253 return (cast_from_oop<intptr_t>(obj) & MinObjAlignmentInBytesMask) == 0;
254 }
255
256 oop oopDesc::decode_heap_oop_not_null(narrowOop v) {
257 assert(!is_null(v), "narrow oop value can never be zero");
258 address base = Universe::narrow_oop_base();
259 int shift = Universe::narrow_oop_shift();
260 oop result = (oop)(void*)((uintptr_t)base + ((uintptr_t)v << shift));
261 assert(check_obj_alignment(result), "address not aligned: " INTPTR_FORMAT, p2i((void*) result));
262 return result;
263 }
264
265 oop oopDesc::decode_heap_oop(narrowOop v) {
266 return is_null(v) ? (oop)NULL : decode_heap_oop_not_null(v);
267 }
268
269 narrowOop oopDesc::encode_heap_oop_not_null(oop v) {
270 assert(!is_null(v), "oop value can never be zero");
271 assert(check_obj_alignment(v), "Address not aligned");
272 assert(Universe::heap()->is_in_reserved(v), "Address not in heap");
273 address base = Universe::narrow_oop_base();
274 int shift = Universe::narrow_oop_shift();
275 uint64_t pd = (uint64_t)(pointer_delta((void*)v, (void*)base, 1));
276 assert(OopEncodingHeapMax > pd, "change encoding max if new encoding");
277 uint64_t result = pd >> shift;
278 assert((result & CONST64(0xffffffff00000000)) == 0, "narrow oop overflow");
279 assert(decode_heap_oop(result) == v, "reversibility");
280 return (narrowOop)result;
281 }
282
283 narrowOop oopDesc::encode_heap_oop(oop v) {
284 return (is_null(v)) ? (narrowOop)0 : encode_heap_oop_not_null(v);
285 }
286
287 narrowOop oopDesc::load_heap_oop(narrowOop* p) { return *p; }
288 oop oopDesc::load_heap_oop(oop* p) { return *p; }
289
290 void oopDesc::store_heap_oop(narrowOop* p, narrowOop v) { *p = v; }
291 void oopDesc::store_heap_oop(oop* p, oop v) { *p = v; }
292
293 // Load and decode an oop out of the Java heap into a wide oop.
294 oop oopDesc::load_decode_heap_oop_not_null(narrowOop* p) {
295 return decode_heap_oop_not_null(load_heap_oop(p));
296 }
297
298 // Load and decode an oop out of the heap accepting null
299 oop oopDesc::load_decode_heap_oop(narrowOop* p) {
300 return decode_heap_oop(load_heap_oop(p));
301 }
302
303 oop oopDesc::load_decode_heap_oop_not_null(oop* p) { return *p; }
304 oop oopDesc::load_decode_heap_oop(oop* p) { return *p; }
305
306 void oopDesc::encode_store_heap_oop_not_null(oop* p, oop v) { *p = v; }
307 void oopDesc::encode_store_heap_oop(oop* p, oop v) { *p = v; }
308
309 // Encode and store a heap oop.
310 void oopDesc::encode_store_heap_oop_not_null(narrowOop* p, oop v) {
311 *p = encode_heap_oop_not_null(v);
312 }
313
314 // Encode and store a heap oop allowing for null.
315 void oopDesc::encode_store_heap_oop(narrowOop* p, oop v) {
316 *p = encode_heap_oop(v);
317 }
318
319 template <DecoratorSet decorators>
320 inline oop oopDesc::obj_field_access(int offset) const { return HeapAccess<decorators>::oop_load_at(as_oop(), offset); }
321 inline oop oopDesc::obj_field(int offset) const { return HeapAccess<>::oop_load_at(as_oop(), offset); }
322
323 inline void oopDesc::obj_field_put(int offset, oop value) { HeapAccess<>::oop_store_at(as_oop(), offset, value); }
324
325 inline jbyte oopDesc::byte_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
326 inline void oopDesc::byte_field_put(int offset, jbyte value) { HeapAccess<>::store_at(as_oop(), offset, value); }
327
328 inline jchar oopDesc::char_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
329 inline void oopDesc::char_field_put(int offset, jchar value) { HeapAccess<>::store_at(as_oop(), offset, value); }
330
331 inline jboolean oopDesc::bool_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
332 inline void oopDesc::bool_field_put(int offset, jboolean value) { HeapAccess<>::store_at(as_oop(), offset, jboolean(value & 1)); }
333
334 inline jshort oopDesc::short_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
335 inline void oopDesc::short_field_put(int offset, jshort value) { HeapAccess<>::store_at(as_oop(), offset, value); }
336
337 inline jint oopDesc::int_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
338 inline void oopDesc::int_field_put(int offset, jint value) { HeapAccess<>::store_at(as_oop(), offset, value); }
339
340 inline jlong oopDesc::long_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
341 inline void oopDesc::long_field_put(int offset, jlong value) { HeapAccess<>::store_at(as_oop(), offset, value); }
342
343 inline jfloat oopDesc::float_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
344 inline void oopDesc::float_field_put(int offset, jfloat value) { HeapAccess<>::store_at(as_oop(), offset, value); }
345
346 inline jdouble oopDesc::double_field(int offset) const { return HeapAccess<>::load_at(as_oop(), offset); }
347 inline void oopDesc::double_field_put(int offset, jdouble value) { HeapAccess<>::store_at(as_oop(), offset, value); }
348
349 bool oopDesc::is_locked() const {
350 return mark()->is_locked();
351 }
352
353 bool oopDesc::is_unlocked() const {
354 return mark()->is_unlocked();
355 }
356
357 bool oopDesc::has_bias_pattern() const {
358 return mark()->has_bias_pattern();
359 }
360
361 // Used only for markSweep, scavenging
362 bool oopDesc::is_gc_marked() const {
363 return mark()->is_marked();
364 }
365
366 // Used by scavengers
367 bool oopDesc::is_forwarded() const {
368 // The extra heap check is needed since the obj might be locked, in which case the
369 // mark would point to a stack location and have the sentinel bit cleared
370 return mark()->is_marked();
371 }
372
373 // Used by scavengers
374 void oopDesc::forward_to(oop p) {
375 assert(check_obj_alignment(p),
376 "forwarding to something not aligned");
377 assert(Universe::heap()->is_in_reserved(p),
378 "forwarding to something not in heap");
379 assert(!is_archive_object(oop(this)) &&
380 !is_archive_object(p),
381 "forwarding archive object");
382 markOop m = markOopDesc::encode_pointer_as_mark(p);
383 assert(m->decode_pointer() == p, "encoding must be reversable");
384 set_mark(m);
385 }
386
387 // Used by parallel scavengers
388 bool oopDesc::cas_forward_to(oop p, markOop compare) {
389 assert(check_obj_alignment(p),
390 "forwarding to something not aligned");
391 assert(Universe::heap()->is_in_reserved(p),
392 "forwarding to something not in heap");
393 markOop m = markOopDesc::encode_pointer_as_mark(p);
394 assert(m->decode_pointer() == p, "encoding must be reversable");
395 return cas_set_mark(m, compare) == compare;
396 }
397
398 #if INCLUDE_ALL_GCS
399 oop oopDesc::forward_to_atomic(oop p) {
400 markOop oldMark = mark();
401 markOop forwardPtrMark = markOopDesc::encode_pointer_as_mark(p);
402 markOop curMark;
403
404 assert(forwardPtrMark->decode_pointer() == p, "encoding must be reversable");
405 assert(sizeof(markOop) == sizeof(intptr_t), "CAS below requires this.");
406
407 while (!oldMark->is_marked()) {
408 curMark = Atomic::cmpxchg(forwardPtrMark, &_mark, oldMark);
409 assert(is_forwarded(), "object should have been forwarded");
410 if (curMark == oldMark) {
411 return NULL;
412 }
413 // If the CAS was unsuccessful then curMark->is_marked()
414 // should return true as another thread has CAS'd in another
415 // forwarding pointer.
416 oldMark = curMark;
417 }
418 return forwardee();
419 }
420 #endif
421
422 // Note that the forwardee is not the same thing as the displaced_mark.
423 // The forwardee is used when copying during scavenge and mark-sweep.
424 // It does need to clear the low two locking- and GC-related bits.
425 oop oopDesc::forwardee() const {
426 return (oop) mark()->decode_pointer();
427 }
428
429 // The following method needs to be MT safe.
430 uint oopDesc::age() const {
431 assert(!is_forwarded(), "Attempt to read age from forwarded mark");
432 if (has_displaced_mark()) {
433 return displaced_mark()->age();
434 } else {
435 return mark()->age();
436 }
437 }
438
439 void oopDesc::incr_age() {
440 assert(!is_forwarded(), "Attempt to increment age of forwarded mark");
441 if (has_displaced_mark()) {
442 set_displaced_mark(displaced_mark()->incr_age());
443 } else {
444 set_mark(mark()->incr_age());
445 }
446 }
447
448 #if INCLUDE_ALL_GCS
449 void oopDesc::pc_follow_contents(ParCompactionManager* cm) {
450 klass()->oop_pc_follow_contents(this, cm);
451 }
452
453 void oopDesc::pc_update_contents(ParCompactionManager* cm) {
454 Klass* k = klass();
455 if (!k->is_typeArray_klass()) {
456 // It might contain oops beyond the header, so take the virtual call.
457 k->oop_pc_update_pointers(this, cm);
458 }
459 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
460 }
461
462 void oopDesc::ps_push_contents(PSPromotionManager* pm) {
463 Klass* k = klass();
464 if (!k->is_typeArray_klass()) {
465 // It might contain oops beyond the header, so take the virtual call.
466 k->oop_ps_push_contents(this, pm);
467 }
468 // Else skip it. The TypeArrayKlass in the header never needs scavenging.
469 }
470 #endif // INCLUDE_ALL_GCS
471
472 #define OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
473 \
474 void oopDesc::oop_iterate(OopClosureType* blk) { \
475 klass()->oop_oop_iterate##nv_suffix(this, blk); \
476 } \
477 \
478 void oopDesc::oop_iterate(OopClosureType* blk, MemRegion mr) { \
479 klass()->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
480 }
481
482 #define OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
483 \
484 int oopDesc::oop_iterate_size(OopClosureType* blk) { \
485 Klass* k = klass(); \
486 int size = size_given_klass(k); \
487 k->oop_oop_iterate##nv_suffix(this, blk); \
488 return size; \
489 } \
490 \
491 int oopDesc::oop_iterate_size(OopClosureType* blk, MemRegion mr) { \
492 Klass* k = klass(); \
493 int size = size_given_klass(k); \
494 k->oop_oop_iterate_bounded##nv_suffix(this, blk, mr); \
495 return size; \
496 }
497
498 int oopDesc::oop_iterate_no_header(OopClosure* blk) {
499 // The NoHeaderExtendedOopClosure wraps the OopClosure and proxies all
500 // the do_oop calls, but turns off all other features in ExtendedOopClosure.
501 NoHeaderExtendedOopClosure cl(blk);
502 return oop_iterate_size(&cl);
503 }
504
505 int oopDesc::oop_iterate_no_header(OopClosure* blk, MemRegion mr) {
506 NoHeaderExtendedOopClosure cl(blk);
507 return oop_iterate_size(&cl, mr);
508 }
509
510 #if INCLUDE_ALL_GCS
511 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
512 \
513 inline void oopDesc::oop_iterate_backwards(OopClosureType* blk) { \
514 klass()->oop_oop_iterate_backwards##nv_suffix(this, blk); \
515 }
516 #else
517 #define OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
518 #endif // INCLUDE_ALL_GCS
519
520 #define ALL_OOPDESC_OOP_ITERATE(OopClosureType, nv_suffix) \
521 OOP_ITERATE_DEFN(OopClosureType, nv_suffix) \
522 OOP_ITERATE_SIZE_DEFN(OopClosureType, nv_suffix) \
523 OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix)
524
525 ALL_OOP_OOP_ITERATE_CLOSURES_1(ALL_OOPDESC_OOP_ITERATE)
526 ALL_OOP_OOP_ITERATE_CLOSURES_2(ALL_OOPDESC_OOP_ITERATE)
527
528 intptr_t oopDesc::identity_hash() {
529 // Fast case; if the object is unlocked and the hash value is set, no locking is needed
530 // Note: The mark must be read into local variable to avoid concurrent updates.
531 markOop mrk = mark();
532 if (mrk->is_unlocked() && !mrk->has_no_hash()) {
533 return mrk->hash();
534 } else if (mrk->is_marked()) {
535 return mrk->hash();
536 } else {
537 return slow_identity_hash();
538 }
539 }
540
541 bool oopDesc::has_displaced_mark() const {
542 return mark()->has_displaced_mark_helper();
543 }
544
545 markOop oopDesc::displaced_mark() const {
546 return mark()->displaced_mark_helper();
547 }
548
549 void oopDesc::set_displaced_mark(markOop m) {
550 mark()->set_displaced_mark_helper(m);
551 }
552
553 #endif // SHARE_VM_OOPS_OOP_INLINE_HPP