1 /*
2 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25
26 #include "gc/shenandoah/shenandoahAsserts.hpp"
27 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
28 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
29 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
31 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
32 #include "gc/shenandoah/shenandoahUtils.hpp"
33 #include "gc/shenandoah/shenandoahVerifier.hpp"
34 #include "memory/allocation.hpp"
35 #include "memory/iterator.inline.hpp"
36 #include "memory/resourceArea.hpp"
37
38 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
39 #ifdef verify_oop
40 #undef verify_oop
41 #endif
42
43 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
44 private:
45 const char* _phase;
46 ShenandoahVerifier::VerifyOptions _options;
47 ShenandoahVerifierStack* _stack;
48 ShenandoahHeap* _heap;
49 MarkBitMap* _map;
50 ShenandoahLivenessData* _ld;
51 void* _interior_loc;
52 oop _loc;
53
54 public:
55 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
56 const char* phase, ShenandoahVerifier::VerifyOptions options) :
57 _phase(phase),
58 _options(options),
59 _stack(stack),
60 _heap(ShenandoahHeap::heap()),
61 _map(map),
62 _ld(ld),
63 _interior_loc(NULL),
64 _loc(NULL) { }
65
66 private:
67 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
68 if (!test) {
69 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
70 }
71 }
72
73 template <class T>
74 void do_oop_work(T* p) {
75 T o = RawAccess<>::oop_load(p);
76 if (!CompressedOops::is_null(o)) {
77 oop obj = CompressedOops::decode_not_null(o);
78
79 // Single threaded verification can use faster non-atomic stack and bitmap
80 // methods.
81 //
82 // For performance reasons, only fully verify non-marked field values.
83 // We are here when the host object for *p is already marked.
84
85 HeapWord* addr = (HeapWord*) obj;
86 if (_map->par_mark(addr)) {
87 verify_oop_at(p, obj);
88 _stack->push(ShenandoahVerifierTask(obj));
89 }
90 }
91 }
92
93 void verify_oop(oop obj) {
94 // Perform consistency checks with gradually decreasing safety level. This guarantees
95 // that failure report would not try to touch something that was not yet verified to be
96 // safe to process.
97
98 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
99 "oop must be in heap");
100 check(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),
101 "oop must be aligned");
102
103 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
104 Klass* obj_klass = obj->klass_or_null();
105
106 // Verify that obj is not in dead space:
107 {
108 // Do this before touching obj->size()
109 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
110 "Object klass pointer should not be NULL");
111 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
112 "Object klass pointer must go to metaspace");
113
114 HeapWord *obj_addr = (HeapWord *) obj;
115 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
116 "Object start should be within the region");
117
118 if (!obj_reg->is_humongous()) {
119 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
120 "Object end should be within the region");
121 } else {
122 size_t humongous_start = obj_reg->region_number();
123 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
124 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
125 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
126 "Humongous object is in continuation that fits it");
127 }
128 }
129
130 // ------------ obj is safe at this point --------------
131
132 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
133 "Object should be in active region");
134
135 switch (_options._verify_liveness) {
136 case ShenandoahVerifier::_verify_liveness_disable:
137 // skip
138 break;
139 case ShenandoahVerifier::_verify_liveness_complete:
140 Atomic::add(obj->size() + ShenandoahForwarding::word_size(), &_ld[obj_reg->region_number()]);
141 // fallthrough for fast failure for un-live regions:
142 case ShenandoahVerifier::_verify_liveness_conservative:
143 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
144 "Object must belong to region with live data");
145 break;
146 default:
147 assert(false, "Unhandled liveness verification");
148 }
149 }
150
151 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
152
153 ShenandoahHeapRegion* fwd_reg = NULL;
154
155 if (!oopDesc::equals_raw(obj, fwd)) {
156 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
157 "Forwardee must be in heap");
158 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
159 "Forwardee is set");
160 check(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),
161 "Forwardee must be aligned");
162
163 // Do this before touching fwd->size()
164 Klass* fwd_klass = fwd->klass_or_null();
165 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
166 "Forwardee klass pointer should not be NULL");
167 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
168 "Forwardee klass pointer must go to metaspace");
169 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
170 "Forwardee klass pointer must go to metaspace");
171
172 fwd_reg = _heap->heap_region_containing(fwd);
173
174 // Verify that forwardee is not in the dead space:
175 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
176 "Should have no humongous forwardees");
177
178 HeapWord *fwd_addr = (HeapWord *) fwd;
179 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
180 "Forwardee start should be within the region");
181 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
182 "Forwardee end should be within the region");
183
184 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
185 check(ShenandoahAsserts::_safe_oop, obj, oopDesc::equals_raw(fwd, fwd2),
186 "Double forwarding");
187 } else {
188 fwd_reg = obj_reg;
189 }
190
191 // ------------ obj and fwd are safe at this point --------------
192
193 switch (_options._verify_marked) {
194 case ShenandoahVerifier::_verify_marked_disable:
195 // skip
196 break;
197 case ShenandoahVerifier::_verify_marked_incomplete:
198 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
199 "Must be marked in incomplete bitmap");
200 break;
201 case ShenandoahVerifier::_verify_marked_complete:
202 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
203 "Must be marked in complete bitmap");
204 break;
205 default:
206 assert(false, "Unhandled mark verification");
207 }
208
209 switch (_options._verify_forwarded) {
210 case ShenandoahVerifier::_verify_forwarded_disable:
211 // skip
212 break;
213 case ShenandoahVerifier::_verify_forwarded_none: {
214 check(ShenandoahAsserts::_safe_all, obj, oopDesc::equals_raw(obj, fwd),
215 "Should not be forwarded");
216 break;
217 }
218 case ShenandoahVerifier::_verify_forwarded_allow: {
219 if (!oopDesc::equals_raw(obj, fwd)) {
220 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
221 "Forwardee should be in another region");
222 }
223 break;
224 }
225 default:
226 assert(false, "Unhandled forwarding verification");
227 }
228
229 switch (_options._verify_cset) {
230 case ShenandoahVerifier::_verify_cset_disable:
231 // skip
232 break;
233 case ShenandoahVerifier::_verify_cset_none:
234 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
235 "Should not have references to collection set");
236 break;
237 case ShenandoahVerifier::_verify_cset_forwarded:
238 if (_heap->in_collection_set(obj)) {
239 check(ShenandoahAsserts::_safe_all, obj, !oopDesc::equals_raw(obj, fwd),
240 "Object in collection set, should have forwardee");
241 }
242 break;
243 default:
244 assert(false, "Unhandled cset verification");
245 }
246
247 }
248
249 public:
250 /**
251 * Verify object with known interior reference.
252 * @param p interior reference where the object is referenced from; can be off-heap
253 * @param obj verified object
254 */
255 template <class T>
256 void verify_oop_at(T* p, oop obj) {
257 _interior_loc = p;
258 verify_oop(obj);
259 _interior_loc = NULL;
260 }
261
262 /**
263 * Verify object without known interior reference.
264 * Useful when picking up the object at known offset in heap,
265 * but without knowing what objects reference it.
266 * @param obj verified object
267 */
268 void verify_oop_standalone(oop obj) {
269 _interior_loc = NULL;
270 verify_oop(obj);
271 _interior_loc = NULL;
272 }
273
274 /**
275 * Verify oop fields from this object.
276 * @param obj host object for verified fields
277 */
278 void verify_oops_from(oop obj) {
279 _loc = obj;
280 obj->oop_iterate(this);
281 _loc = NULL;
282 }
283
284 virtual void do_oop(oop* p) { do_oop_work(p); }
285 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
286 };
287
288 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
289 private:
290 size_t _used, _committed, _garbage;
291 public:
292 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
293
294 void heap_region_do(ShenandoahHeapRegion* r) {
295 _used += r->used();
296 _garbage += r->garbage();
297 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
298 }
299
300 size_t used() { return _used; }
301 size_t committed() { return _committed; }
302 size_t garbage() { return _garbage; }
303 };
304
305 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
306 private:
307 ShenandoahHeap* _heap;
308 const char* _phase;
309 ShenandoahVerifier::VerifyRegions _regions;
310 public:
311 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
312 _heap(ShenandoahHeap::heap()),
313 _phase(phase),
314 _regions(regions) {};
315
316 void print_failure(ShenandoahHeapRegion* r, const char* label) {
317 ResourceMark rm;
318
319 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
320
321 stringStream ss;
322 r->print_on(&ss);
323 msg.append("%s", ss.as_string());
324
325 report_vm_error(__FILE__, __LINE__, msg.buffer());
326 }
327
328 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
329 if (!test) {
330 print_failure(r, msg);
331 }
332 }
333
334 void heap_region_do(ShenandoahHeapRegion* r) {
335 switch (_regions) {
336 case ShenandoahVerifier::_verify_regions_disable:
337 break;
338 case ShenandoahVerifier::_verify_regions_notrash:
339 verify(r, !r->is_trash(),
340 "Should not have trash regions");
341 break;
342 case ShenandoahVerifier::_verify_regions_nocset:
343 verify(r, !r->is_cset(),
344 "Should not have cset regions");
345 break;
346 case ShenandoahVerifier::_verify_regions_notrash_nocset:
347 verify(r, !r->is_trash(),
348 "Should not have trash regions");
349 verify(r, !r->is_cset(),
350 "Should not have cset regions");
351 break;
352 default:
353 ShouldNotReachHere();
354 }
355
356 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
357 "Capacity should match region size");
358
359 verify(r, r->bottom() <= r->top(),
360 "Region top should not be less than bottom");
361
362 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
363 "Region TAMS should not be less than bottom");
364
365 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
366 "Complete TAMS should not be larger than top");
367
368 verify(r, r->get_live_data_bytes() <= r->capacity(),
369 "Live data cannot be larger than capacity");
370
371 verify(r, r->garbage() <= r->capacity(),
372 "Garbage cannot be larger than capacity");
373
374 verify(r, r->used() <= r->capacity(),
375 "Used cannot be larger than capacity");
376
377 verify(r, r->get_shared_allocs() <= r->capacity(),
378 "Shared alloc count should not be larger than capacity");
379
380 verify(r, r->get_tlab_allocs() <= r->capacity(),
381 "TLAB alloc count should not be larger than capacity");
382
383 verify(r, r->get_gclab_allocs() <= r->capacity(),
384 "GCLAB alloc count should not be larger than capacity");
385
386 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
387 "Accurate accounting: shared + TLAB + GCLAB = used");
388
389 verify(r, !r->is_empty() || !r->has_live(),
390 "Empty regions should not have live data");
391
392 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
393 "Transitional: region flags and collection set agree");
394
395 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
396 "Non-empty regions should have first seqnum set");
397
398 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
399 "Non-empty regions should have first seqnum set to either GC or mutator");
400
401 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
402 "Non-empty regions should have last seqnum set");
403
404 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
405 "Non-empty regions should have last seqnum set to either GC or mutator");
406
407 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
408 "First seqnum should not be greater than last timestamp");
409
410 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
411 "First mutator seqnum should not be greater than last seqnum");
412
413 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
414 "First GC seqnum should not be greater than last seqnum");
415 }
416 };
417
418 class ShenandoahVerifierReachableTask : public AbstractGangTask {
419 private:
420 const char* _label;
421 ShenandoahRootProcessor* _rp;
422 ShenandoahVerifier::VerifyOptions _options;
423 ShenandoahHeap* _heap;
424 ShenandoahLivenessData* _ld;
425 MarkBitMap* _bitmap;
426 volatile size_t _processed;
427
428 public:
429 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
430 ShenandoahLivenessData* ld,
431 ShenandoahRootProcessor* rp,
432 const char* label,
433 ShenandoahVerifier::VerifyOptions options) :
434 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
435 _label(label),
436 _rp(rp),
437 _options(options),
438 _heap(ShenandoahHeap::heap()),
439 _ld(ld),
440 _bitmap(bitmap),
441 _processed(0) {};
442
443 size_t processed() {
444 return _processed;
445 }
446
447 virtual void work(uint worker_id) {
448 ResourceMark rm;
449 ShenandoahVerifierStack stack;
450
451 // On level 2, we need to only check the roots once.
452 // On level 3, we want to check the roots, and seed the local stack.
453 // It is a lesser evil to accept multiple root scans at level 3, because
454 // extended parallelism would buy us out.
455 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
456 || (ShenandoahVerifyLevel >= 3)) {
457 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
458 ShenandoahMessageBuffer("%s, Roots", _label),
459 _options);
460 _rp->process_all_roots_slow(&cl);
461 }
462
463 size_t processed = 0;
464
465 if (ShenandoahVerifyLevel >= 3) {
466 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
467 ShenandoahMessageBuffer("%s, Reachable", _label),
468 _options);
469 while (!stack.is_empty()) {
470 processed++;
471 ShenandoahVerifierTask task = stack.pop();
472 cl.verify_oops_from(task.obj());
473 }
474 }
475
476 Atomic::add(processed, &_processed);
477 }
478 };
479
480 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
481 private:
482 const char* _label;
483 ShenandoahVerifier::VerifyOptions _options;
484 ShenandoahHeap *_heap;
485 MarkBitMap* _bitmap;
486 ShenandoahLivenessData* _ld;
487 volatile size_t _claimed;
488 volatile size_t _processed;
489
490 public:
491 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
492 ShenandoahLivenessData* ld,
493 const char* label,
494 ShenandoahVerifier::VerifyOptions options) :
495 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
496 _label(label),
497 _options(options),
498 _heap(ShenandoahHeap::heap()),
499 _bitmap(bitmap),
500 _ld(ld),
501 _claimed(0),
502 _processed(0) {};
503
504 size_t processed() {
505 return _processed;
506 }
507
508 virtual void work(uint worker_id) {
509 ShenandoahVerifierStack stack;
510 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
511 ShenandoahMessageBuffer("%s, Marked", _label),
512 _options);
513
514 while (true) {
515 size_t v = Atomic::add(1u, &_claimed) - 1;
516 if (v < _heap->num_regions()) {
517 ShenandoahHeapRegion* r = _heap->get_region(v);
518 if (!r->is_humongous() && !r->is_trash()) {
519 work_regular(r, stack, cl);
520 } else if (r->is_humongous_start()) {
521 work_humongous(r, stack, cl);
522 }
523 } else {
524 break;
525 }
526 }
527 }
528
529 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
530 size_t processed = 0;
531 HeapWord* obj = r->bottom() + ShenandoahForwarding::word_size();
532 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
533 verify_and_follow(obj, stack, cl, &processed);
534 }
535 Atomic::add(processed, &_processed);
536 }
537
538 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
539 size_t processed = 0;
540 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
541 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
542
543 // Bitmaps, before TAMS
544 if (tams > r->bottom()) {
545 HeapWord* start = r->bottom() + ShenandoahForwarding::word_size();
546 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
547
548 while (addr < tams) {
549 verify_and_follow(addr, stack, cl, &processed);
550 addr += ShenandoahForwarding::word_size();
551 if (addr < tams) {
552 addr = mark_bit_map->get_next_marked_addr(addr, tams);
553 }
554 }
555 }
556
557 // Size-based, after TAMS
558 {
559 HeapWord* limit = r->top();
560 HeapWord* addr = tams + ShenandoahForwarding::word_size();
561
562 while (addr < limit) {
563 verify_and_follow(addr, stack, cl, &processed);
564 addr += oop(addr)->size() + ShenandoahForwarding::word_size();
565 }
566 }
567
568 Atomic::add(processed, &_processed);
569 }
570
571 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
572 if (!_bitmap->par_mark(addr)) return;
573
574 // Verify the object itself:
575 oop obj = oop(addr);
576 cl.verify_oop_standalone(obj);
577
578 // Verify everything reachable from that object too, hopefully realizing
579 // everything was already marked, and never touching further:
580 cl.verify_oops_from(obj);
581 (*processed)++;
582
583 while (!stack.is_empty()) {
584 ShenandoahVerifierTask task = stack.pop();
585 cl.verify_oops_from(task.obj());
586 (*processed)++;
587 }
588 }
589 };
590
591 class VerifyThreadGCState : public ThreadClosure {
592 private:
593 const char* _label;
594 char _expected;
595
596 public:
597 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
598 void do_thread(Thread* t) {
599 char actual = ShenandoahThreadLocalData::gc_state(t);
600 if (actual != _expected) {
601 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
602 }
603 }
604 };
605
606 void ShenandoahVerifier::verify_at_safepoint(const char *label,
607 VerifyForwarded forwarded, VerifyMarked marked,
608 VerifyCollectionSet cset,
609 VerifyLiveness liveness, VerifyRegions regions,
610 VerifyGCState gcstate) {
611 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
612 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
613
614 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
615 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
616
617 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
618
619 // GC state checks
620 {
621 char expected = -1;
622 bool enabled;
623 switch (gcstate) {
624 case _verify_gcstate_disable:
625 enabled = false;
626 break;
627 case _verify_gcstate_forwarded:
628 enabled = true;
629 expected = ShenandoahHeap::HAS_FORWARDED;
630 break;
631 case _verify_gcstate_evacuation:
632 enabled = true;
633 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
634 break;
635 case _verify_gcstate_stable:
636 enabled = true;
637 expected = ShenandoahHeap::STABLE;
638 break;
639 default:
640 enabled = false;
641 assert(false, "Unhandled gc-state verification");
642 }
643
644 if (enabled) {
645 char actual = _heap->gc_state();
646 if (actual != expected) {
647 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
648 }
649
650 VerifyThreadGCState vtgcs(label, expected);
651 Threads::java_threads_do(&vtgcs);
652 }
653 }
654
655 // Heap size checks
656 {
657 ShenandoahHeapLocker lock(_heap->lock());
658
659 ShenandoahCalculateRegionStatsClosure cl;
660 _heap->heap_region_iterate(&cl);
661 size_t heap_used = _heap->used();
662 guarantee(cl.used() == heap_used,
663 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
664 label, heap_used/K, cl.used()/K);
665
666 size_t heap_committed = _heap->committed();
667 guarantee(cl.committed() == heap_committed,
668 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
669 label, heap_committed/K, cl.committed()/K);
670 }
671
672 // Internal heap region checks
673 if (ShenandoahVerifyLevel >= 1) {
674 ShenandoahVerifyHeapRegionClosure cl(label, regions);
675 _heap->heap_region_iterate(&cl);
676 }
677
678 OrderAccess::fence();
679 _heap->make_parsable(false);
680
681 // Allocate temporary bitmap for storing marking wavefront:
682 _verification_bit_map->clear();
683
684 // Allocate temporary array for storing liveness data
685 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
686 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
687
688 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
689
690 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
691 // This verifies what application can see, since it only cares about reachable objects.
692 size_t count_reachable = 0;
693 if (ShenandoahVerifyLevel >= 2) {
694 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
695 ShenandoahPhaseTimings::_num_phases); // no need for stats
696
697 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
698 _heap->workers()->run_task(&task);
699 count_reachable = task.processed();
700 }
701
702 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
703 // not the application, can see during the region scans. There is no reason to process the objects
704 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
705 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
706 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
707 // version
708
709 size_t count_marked = 0;
710 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
711 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
712 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
713 _heap->workers()->run_task(&task);
714 count_marked = task.processed();
715 } else {
716 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
717 }
718
719 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
720 // marked objects.
721
722 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
723 for (size_t i = 0; i < _heap->num_regions(); i++) {
724 ShenandoahHeapRegion* r = _heap->get_region(i);
725
726 juint verf_live = 0;
727 if (r->is_humongous()) {
728 // For humongous objects, test if start region is marked live, and if so,
729 // all humongous regions in that chain have live data equal to their "used".
730 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
731 if (start_live > 0) {
732 verf_live = (juint)(r->used() / HeapWordSize);
733 }
734 } else {
735 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
736 }
737
738 size_t reg_live = r->get_live_data_words();
739 if (reg_live != verf_live) {
740 ResourceMark rm;
741 stringStream ss;
742 r->print_on(&ss);
743 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
744 label, reg_live, verf_live, ss.as_string());
745 }
746 }
747 }
748
749 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
750 label, ShenandoahVerifyLevel, count_reachable, count_marked);
751
752 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
753 }
754
755 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
756 verify_at_safepoint(
757 "Generic Verification",
758 _verify_forwarded_allow, // conservatively allow forwarded
759 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
760 _verify_cset_disable, // cset may be inconsistent
761 _verify_liveness_disable, // no reliable liveness data
762 _verify_regions_disable, // no reliable region data
763 _verify_gcstate_disable // no data about gcstate
764 );
765 }
766
767 void ShenandoahVerifier::verify_before_concmark() {
768 if (_heap->has_forwarded_objects()) {
769 verify_at_safepoint(
770 "Before Mark",
771 _verify_forwarded_allow, // may have forwarded references
772 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
773 _verify_cset_forwarded, // allow forwarded references to cset
774 _verify_liveness_disable, // no reliable liveness data
775 _verify_regions_notrash, // no trash regions
776 _verify_gcstate_forwarded // there are forwarded objects
777 );
778 } else {
779 verify_at_safepoint(
780 "Before Mark",
781 _verify_forwarded_none, // UR should have fixed up
782 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
783 _verify_cset_none, // UR should have fixed this
784 _verify_liveness_disable, // no reliable liveness data
785 _verify_regions_notrash, // no trash regions
786 _verify_gcstate_stable // there are no forwarded objects
787 );
788 }
789 }
790
791 void ShenandoahVerifier::verify_after_concmark() {
792 verify_at_safepoint(
793 "After Mark",
794 _verify_forwarded_none, // no forwarded references
795 _verify_marked_complete, // bitmaps as precise as we can get
796 _verify_cset_none, // no references to cset anymore
797 _verify_liveness_complete, // liveness data must be complete here
798 _verify_regions_disable, // trash regions not yet recycled
799 _verify_gcstate_stable // mark should have stabilized the heap
800 );
801 }
802
803 void ShenandoahVerifier::verify_before_evacuation() {
804 verify_at_safepoint(
805 "Before Evacuation",
806 _verify_forwarded_none, // no forwarded references
807 _verify_marked_complete, // walk over marked objects too
808 _verify_cset_disable, // non-forwarded references to cset expected
809 _verify_liveness_complete, // liveness data must be complete here
810 _verify_regions_disable, // trash regions not yet recycled
811 _verify_gcstate_stable // mark should have stabilized the heap
812 );
813 }
814
815 void ShenandoahVerifier::verify_during_evacuation() {
816 verify_at_safepoint(
817 "During Evacuation",
818 _verify_forwarded_allow, // some forwarded references are allowed
819 _verify_marked_disable, // walk only roots
820 _verify_cset_disable, // some cset references are not forwarded yet
821 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
822 _verify_regions_disable, // trash regions not yet recycled
823 _verify_gcstate_evacuation // evacuation is in progress
824 );
825 }
826
827 void ShenandoahVerifier::verify_after_evacuation() {
828 verify_at_safepoint(
829 "After Evacuation",
830 _verify_forwarded_allow, // objects are still forwarded
831 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
832 _verify_cset_forwarded, // all cset refs are fully forwarded
833 _verify_liveness_disable, // no reliable liveness data anymore
834 _verify_regions_notrash, // trash regions have been recycled already
835 _verify_gcstate_forwarded // evacuation produced some forwarded objects
836 );
837 }
838
839 void ShenandoahVerifier::verify_before_updaterefs() {
840 verify_at_safepoint(
841 "Before Updating References",
842 _verify_forwarded_allow, // forwarded references allowed
843 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
844 _verify_cset_forwarded, // all cset refs are fully forwarded
845 _verify_liveness_disable, // no reliable liveness data anymore
846 _verify_regions_notrash, // trash regions have been recycled already
847 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
848 );
849 }
850
851 void ShenandoahVerifier::verify_after_updaterefs() {
852 verify_at_safepoint(
853 "After Updating References",
854 _verify_forwarded_none, // no forwarded references
855 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
856 _verify_cset_none, // no cset references, all updated
857 _verify_liveness_disable, // no reliable liveness data anymore
858 _verify_regions_nocset, // no cset regions, trash regions have appeared
859 _verify_gcstate_stable // update refs had cleaned up forwarded objects
860 );
861 }
862
863 void ShenandoahVerifier::verify_after_degenerated() {
864 verify_at_safepoint(
865 "After Degenerated GC",
866 _verify_forwarded_none, // all objects are non-forwarded
867 _verify_marked_complete, // all objects are marked in complete bitmap
868 _verify_cset_none, // no cset references
869 _verify_liveness_disable, // no reliable liveness data anymore
870 _verify_regions_notrash_nocset, // no trash, no cset
871 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
872 );
873 }
874
875 void ShenandoahVerifier::verify_before_traversal() {
876 verify_at_safepoint(
877 "Before Traversal",
878 _verify_forwarded_none, // cannot have forwarded objects
879 _verify_marked_disable, // bitmaps are not relevant before traversal
880 _verify_cset_none, // no cset references before traversal
881 _verify_liveness_disable, // no reliable liveness data anymore
882 _verify_regions_notrash_nocset, // no trash and no cset regions
883 _verify_gcstate_stable // nothing forwarded before traversal
884 );
885 }
886
887 void ShenandoahVerifier::verify_after_traversal() {
888 verify_at_safepoint(
889 "After Traversal",
890 _verify_forwarded_none, // cannot have forwarded objects
891 _verify_marked_complete, // should have complete marking after traversal
892 _verify_cset_none, // no cset references left after traversal
893 _verify_liveness_disable, // liveness data is not collected for new allocations
894 _verify_regions_nocset, // no cset regions, trash regions allowed
895 _verify_gcstate_stable // nothing forwarded after traversal
896 );
897 }
898
899 void ShenandoahVerifier::verify_before_fullgc() {
900 verify_at_safepoint(
901 "Before Full GC",
902 _verify_forwarded_allow, // can have forwarded objects
903 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
904 _verify_cset_disable, // cset might be foobared
905 _verify_liveness_disable, // no reliable liveness data anymore
906 _verify_regions_disable, // no reliable region data here
907 _verify_gcstate_disable // no reliable gcstate data
908 );
909 }
910
911 void ShenandoahVerifier::verify_after_fullgc() {
912 verify_at_safepoint(
913 "After Full GC",
914 _verify_forwarded_none, // all objects are non-forwarded
915 _verify_marked_complete, // all objects are marked in complete bitmap
916 _verify_cset_none, // no cset references
917 _verify_liveness_disable, // no reliable liveness data anymore
918 _verify_regions_notrash_nocset, // no trash, no cset
919 _verify_gcstate_stable // full gc cleaned up everything
920 );
921 }
922
923 class ShenandoahVerifyNoForwared : public OopClosure {
924 private:
925 template <class T>
926 void do_oop_work(T* p) {
927 T o = RawAccess<>::oop_load(p);
928 if (!CompressedOops::is_null(o)) {
929 oop obj = CompressedOops::decode_not_null(o);
930 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
931 if (!oopDesc::equals_raw(obj, fwd)) {
932 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
933 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
934 }
935 }
936 }
937
938 public:
939 void do_oop(narrowOop* p) { do_oop_work(p); }
940 void do_oop(oop* p) { do_oop_work(p); }
941 };
942
943 void ShenandoahVerifier::verify_roots_no_forwarded() {
944 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
945 ShenandoahRootProcessor rp(_heap, 1, ShenandoahPhaseTimings::_num_phases); // no need for stats
946 ShenandoahVerifyNoForwared cl;
947 rp.process_all_roots_slow(&cl);
948 }
949