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((uint) obj->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 = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
281 obj->oop_iterate(this);
282 _loc = NULL;
283 }
284
285 virtual void do_oop(oop* p) { do_oop_work(p); }
286 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
287 };
288
289 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
290 private:
291 size_t _used, _committed, _garbage;
292 public:
293 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
294
295 void heap_region_do(ShenandoahHeapRegion* r) {
296 _used += r->used();
297 _garbage += r->garbage();
298 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
299 }
300
301 size_t used() { return _used; }
302 size_t committed() { return _committed; }
303 size_t garbage() { return _garbage; }
304 };
305
306 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
307 private:
308 ShenandoahHeap* _heap;
309 const char* _phase;
310 ShenandoahVerifier::VerifyRegions _regions;
311 public:
312 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
313 _heap(ShenandoahHeap::heap()),
314 _phase(phase),
315 _regions(regions) {};
316
317 void print_failure(ShenandoahHeapRegion* r, const char* label) {
318 ResourceMark rm;
319
320 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
321
322 stringStream ss;
323 r->print_on(&ss);
324 msg.append("%s", ss.as_string());
325
326 report_vm_error(__FILE__, __LINE__, msg.buffer());
327 }
328
329 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
330 if (!test) {
331 print_failure(r, msg);
332 }
333 }
334
335 void heap_region_do(ShenandoahHeapRegion* r) {
336 switch (_regions) {
337 case ShenandoahVerifier::_verify_regions_disable:
338 break;
339 case ShenandoahVerifier::_verify_regions_notrash:
340 verify(r, !r->is_trash(),
341 "Should not have trash regions");
342 break;
343 case ShenandoahVerifier::_verify_regions_nocset:
344 verify(r, !r->is_cset(),
345 "Should not have cset regions");
346 break;
347 case ShenandoahVerifier::_verify_regions_notrash_nocset:
348 verify(r, !r->is_trash(),
349 "Should not have trash regions");
350 verify(r, !r->is_cset(),
351 "Should not have cset regions");
352 break;
353 default:
354 ShouldNotReachHere();
355 }
356
357 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
358 "Capacity should match region size");
359
360 verify(r, r->bottom() <= r->top(),
361 "Region top should not be less than bottom");
362
363 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
364 "Region TAMS should not be less than bottom");
365
366 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
367 "Complete TAMS should not be larger than top");
368
369 verify(r, r->get_live_data_bytes() <= r->capacity(),
370 "Live data cannot be larger than capacity");
371
372 verify(r, r->garbage() <= r->capacity(),
373 "Garbage cannot be larger than capacity");
374
375 verify(r, r->used() <= r->capacity(),
376 "Used cannot be larger than capacity");
377
378 verify(r, r->get_shared_allocs() <= r->capacity(),
379 "Shared alloc count should not be larger than capacity");
380
381 verify(r, r->get_tlab_allocs() <= r->capacity(),
382 "TLAB alloc count should not be larger than capacity");
383
384 verify(r, r->get_gclab_allocs() <= r->capacity(),
385 "GCLAB alloc count should not be larger than capacity");
386
387 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
388 "Accurate accounting: shared + TLAB + GCLAB = used");
389
390 verify(r, !r->is_empty() || !r->has_live(),
391 "Empty regions should not have live data");
392
393 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
394 "Transitional: region flags and collection set agree");
395
396 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
397 "Non-empty regions should have first seqnum set");
398
399 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
400 "Non-empty regions should have first seqnum set to either GC or mutator");
401
402 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
403 "Non-empty regions should have last seqnum set");
404
405 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
406 "Non-empty regions should have last seqnum set to either GC or mutator");
407
408 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
409 "First seqnum should not be greater than last timestamp");
410
411 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
412 "First mutator seqnum should not be greater than last seqnum");
413
414 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
415 "First GC seqnum should not be greater than last seqnum");
416 }
417 };
418
419 class ShenandoahVerifierReachableTask : public AbstractGangTask {
420 private:
421 const char* _label;
422 ShenandoahRootProcessor* _rp;
423 ShenandoahVerifier::VerifyOptions _options;
424 ShenandoahHeap* _heap;
425 ShenandoahLivenessData* _ld;
426 MarkBitMap* _bitmap;
427 volatile size_t _processed;
428
429 public:
430 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
431 ShenandoahLivenessData* ld,
432 ShenandoahRootProcessor* rp,
433 const char* label,
434 ShenandoahVerifier::VerifyOptions options) :
435 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
436 _label(label),
437 _rp(rp),
438 _options(options),
439 _heap(ShenandoahHeap::heap()),
440 _ld(ld),
441 _bitmap(bitmap),
442 _processed(0) {};
443
444 size_t processed() {
445 return _processed;
446 }
447
448 virtual void work(uint worker_id) {
449 ResourceMark rm;
450 ShenandoahVerifierStack stack;
451
452 // On level 2, we need to only check the roots once.
453 // On level 3, we want to check the roots, and seed the local stack.
454 // It is a lesser evil to accept multiple root scans at level 3, because
455 // extended parallelism would buy us out.
456 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
457 || (ShenandoahVerifyLevel >= 3)) {
458 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
459 ShenandoahMessageBuffer("%s, Roots", _label),
460 _options);
461 _rp->process_all_roots_slow(&cl);
462 }
463
464 size_t processed = 0;
465
466 if (ShenandoahVerifyLevel >= 3) {
467 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
468 ShenandoahMessageBuffer("%s, Reachable", _label),
469 _options);
470 while (!stack.is_empty()) {
471 processed++;
472 ShenandoahVerifierTask task = stack.pop();
473 cl.verify_oops_from(task.obj());
474 }
475 }
476
477 Atomic::add(processed, &_processed);
478 }
479 };
480
481 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
482 private:
483 const char* _label;
484 ShenandoahVerifier::VerifyOptions _options;
485 ShenandoahHeap *_heap;
486 MarkBitMap* _bitmap;
487 ShenandoahLivenessData* _ld;
488 volatile size_t _claimed;
489 volatile size_t _processed;
490
491 public:
492 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
493 ShenandoahLivenessData* ld,
494 const char* label,
495 ShenandoahVerifier::VerifyOptions options) :
496 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
497 _label(label),
498 _options(options),
499 _heap(ShenandoahHeap::heap()),
500 _bitmap(bitmap),
501 _ld(ld),
502 _claimed(0),
503 _processed(0) {};
504
505 size_t processed() {
506 return _processed;
507 }
508
509 virtual void work(uint worker_id) {
510 ShenandoahVerifierStack stack;
511 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
512 ShenandoahMessageBuffer("%s, Marked", _label),
513 _options);
514
515 while (true) {
516 size_t v = Atomic::add(1u, &_claimed) - 1;
517 if (v < _heap->num_regions()) {
518 ShenandoahHeapRegion* r = _heap->get_region(v);
519 if (!r->is_humongous() && !r->is_trash()) {
520 work_regular(r, stack, cl);
521 } else if (r->is_humongous_start()) {
522 work_humongous(r, stack, cl);
523 }
524 } else {
525 break;
526 }
527 }
528 }
529
530 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
531 size_t processed = 0;
532 HeapWord* obj = r->bottom();
533 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
534 verify_and_follow(obj, stack, cl, &processed);
535 }
536 Atomic::add(processed, &_processed);
537 }
538
539 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
540 size_t processed = 0;
541 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
542 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
543
544 // Bitmaps, before TAMS
545 if (tams > r->bottom()) {
546 HeapWord* start = r->bottom();
547 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
548
549 while (addr < tams) {
550 verify_and_follow(addr, stack, cl, &processed);
551 addr += 1;
552 if (addr < tams) {
553 addr = mark_bit_map->get_next_marked_addr(addr, tams);
554 }
555 }
556 }
557
558 // Size-based, after TAMS
559 {
560 HeapWord* limit = r->top();
561 HeapWord* addr = tams;
562
563 while (addr < limit) {
564 verify_and_follow(addr, stack, cl, &processed);
565 addr += oop(addr)->size();
566 }
567 }
568
569 Atomic::add(processed, &_processed);
570 }
571
572 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
573 if (!_bitmap->par_mark(addr)) return;
574
575 // Verify the object itself:
576 oop obj = oop(addr);
577 cl.verify_oop_standalone(obj);
578
579 // Verify everything reachable from that object too, hopefully realizing
580 // everything was already marked, and never touching further:
581 cl.verify_oops_from(obj);
582 (*processed)++;
583
584 while (!stack.is_empty()) {
585 ShenandoahVerifierTask task = stack.pop();
586 cl.verify_oops_from(task.obj());
587 (*processed)++;
588 }
589 }
590 };
591
592 class VerifyThreadGCState : public ThreadClosure {
593 private:
594 const char* _label;
595 char _expected;
596
597 public:
598 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
599 void do_thread(Thread* t) {
600 char actual = ShenandoahThreadLocalData::gc_state(t);
601 if (actual != _expected) {
602 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
603 }
604 }
605 };
606
607 void ShenandoahVerifier::verify_at_safepoint(const char *label,
608 VerifyForwarded forwarded, VerifyMarked marked,
609 VerifyCollectionSet cset,
610 VerifyLiveness liveness, VerifyRegions regions,
611 VerifyGCState gcstate) {
612 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
613 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
614
615 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
616 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
617
618 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
619
620 // GC state checks
621 {
622 char expected = -1;
623 bool enabled;
624 switch (gcstate) {
625 case _verify_gcstate_disable:
626 enabled = false;
627 break;
628 case _verify_gcstate_forwarded:
629 enabled = true;
630 expected = ShenandoahHeap::HAS_FORWARDED;
631 break;
632 case _verify_gcstate_evacuation:
633 enabled = true;
634 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
635 break;
636 case _verify_gcstate_stable:
637 enabled = true;
638 expected = ShenandoahHeap::STABLE;
639 break;
640 default:
641 enabled = false;
642 assert(false, "Unhandled gc-state verification");
643 }
644
645 if (enabled) {
646 char actual = _heap->gc_state();
647 if (actual != expected) {
648 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
649 }
650
651 VerifyThreadGCState vtgcs(label, expected);
652 Threads::java_threads_do(&vtgcs);
653 }
654 }
655
656 // Heap size checks
657 {
658 ShenandoahHeapLocker lock(_heap->lock());
659
660 ShenandoahCalculateRegionStatsClosure cl;
661 _heap->heap_region_iterate(&cl);
662 size_t heap_used = _heap->used();
663 guarantee(cl.used() == heap_used,
664 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
665 label, heap_used/K, cl.used()/K);
666
667 size_t heap_committed = _heap->committed();
668 guarantee(cl.committed() == heap_committed,
669 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
670 label, heap_committed/K, cl.committed()/K);
671 }
672
673 // Internal heap region checks
674 if (ShenandoahVerifyLevel >= 1) {
675 ShenandoahVerifyHeapRegionClosure cl(label, regions);
676 _heap->heap_region_iterate(&cl);
677 }
678
679 OrderAccess::fence();
680 _heap->make_parsable(false);
681
682 // Allocate temporary bitmap for storing marking wavefront:
683 _verification_bit_map->clear();
684
685 // Allocate temporary array for storing liveness data
686 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
687 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
688
689 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
690
691 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
692 // This verifies what application can see, since it only cares about reachable objects.
693 size_t count_reachable = 0;
694 if (ShenandoahVerifyLevel >= 2) {
695 ShenandoahRootProcessor rp(_heap, _heap->workers()->active_workers(),
696 ShenandoahPhaseTimings::_num_phases); // no need for stats
697
698 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &rp, label, options);
699 _heap->workers()->run_task(&task);
700 count_reachable = task.processed();
701 }
702
703 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
704 // not the application, can see during the region scans. There is no reason to process the objects
705 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
706 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
707 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
708 // version
709
710 size_t count_marked = 0;
711 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
712 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
713 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
714 _heap->workers()->run_task(&task);
715 count_marked = task.processed();
716 } else {
717 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
718 }
719
720 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
721 // marked objects.
722
723 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
724 for (size_t i = 0; i < _heap->num_regions(); i++) {
725 ShenandoahHeapRegion* r = _heap->get_region(i);
726
727 juint verf_live = 0;
728 if (r->is_humongous()) {
729 // For humongous objects, test if start region is marked live, and if so,
730 // all humongous regions in that chain have live data equal to their "used".
731 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
732 if (start_live > 0) {
733 verf_live = (juint)(r->used() / HeapWordSize);
734 }
735 } else {
736 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
737 }
738
739 size_t reg_live = r->get_live_data_words();
740 if (reg_live != verf_live) {
741 ResourceMark rm;
742 stringStream ss;
743 r->print_on(&ss);
744 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
745 label, reg_live, verf_live, ss.as_string());
746 }
747 }
748 }
749
750 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
751 label, ShenandoahVerifyLevel, count_reachable, count_marked);
752
753 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
754 }
755
756 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
757 verify_at_safepoint(
758 "Generic Verification",
759 _verify_forwarded_allow, // conservatively allow forwarded
760 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
761 _verify_cset_disable, // cset may be inconsistent
762 _verify_liveness_disable, // no reliable liveness data
763 _verify_regions_disable, // no reliable region data
764 _verify_gcstate_disable // no data about gcstate
765 );
766 }
767
768 void ShenandoahVerifier::verify_before_concmark() {
769 if (_heap->has_forwarded_objects()) {
770 verify_at_safepoint(
771 "Before Mark",
772 _verify_forwarded_allow, // may have forwarded references
773 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
774 _verify_cset_forwarded, // allow forwarded references to cset
775 _verify_liveness_disable, // no reliable liveness data
776 _verify_regions_notrash, // no trash regions
777 _verify_gcstate_forwarded // there are forwarded objects
778 );
779 } else {
780 verify_at_safepoint(
781 "Before Mark",
782 _verify_forwarded_none, // UR should have fixed up
783 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
784 _verify_cset_none, // UR should have fixed this
785 _verify_liveness_disable, // no reliable liveness data
786 _verify_regions_notrash, // no trash regions
787 _verify_gcstate_stable // there are no forwarded objects
788 );
789 }
790 }
791
792 void ShenandoahVerifier::verify_after_concmark() {
793 verify_at_safepoint(
794 "After Mark",
795 _verify_forwarded_none, // no forwarded references
796 _verify_marked_complete, // bitmaps as precise as we can get
797 _verify_cset_none, // no references to cset anymore
798 _verify_liveness_complete, // liveness data must be complete here
799 _verify_regions_disable, // trash regions not yet recycled
800 _verify_gcstate_stable // mark should have stabilized the heap
801 );
802 }
803
804 void ShenandoahVerifier::verify_before_evacuation() {
805 verify_at_safepoint(
806 "Before Evacuation",
807 _verify_forwarded_none, // no forwarded references
808 _verify_marked_complete, // walk over marked objects too
809 _verify_cset_disable, // non-forwarded references to cset expected
810 _verify_liveness_complete, // liveness data must be complete here
811 _verify_regions_disable, // trash regions not yet recycled
812 _verify_gcstate_stable // mark should have stabilized the heap
813 );
814 }
815
816 void ShenandoahVerifier::verify_during_evacuation() {
817 verify_at_safepoint(
818 "During Evacuation",
819 _verify_forwarded_allow, // some forwarded references are allowed
820 _verify_marked_disable, // walk only roots
821 _verify_cset_disable, // some cset references are not forwarded yet
822 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
823 _verify_regions_disable, // trash regions not yet recycled
824 _verify_gcstate_evacuation // evacuation is in progress
825 );
826 }
827
828 void ShenandoahVerifier::verify_after_evacuation() {
829 verify_at_safepoint(
830 "After Evacuation",
831 _verify_forwarded_allow, // objects are still forwarded
832 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
833 _verify_cset_forwarded, // all cset refs are fully forwarded
834 _verify_liveness_disable, // no reliable liveness data anymore
835 _verify_regions_notrash, // trash regions have been recycled already
836 _verify_gcstate_forwarded // evacuation produced some forwarded objects
837 );
838 }
839
840 void ShenandoahVerifier::verify_before_updaterefs() {
841 verify_at_safepoint(
842 "Before Updating References",
843 _verify_forwarded_allow, // forwarded references allowed
844 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
845 _verify_cset_forwarded, // all cset refs are fully forwarded
846 _verify_liveness_disable, // no reliable liveness data anymore
847 _verify_regions_notrash, // trash regions have been recycled already
848 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
849 );
850 }
851
852 void ShenandoahVerifier::verify_after_updaterefs() {
853 verify_at_safepoint(
854 "After Updating References",
855 _verify_forwarded_none, // no forwarded references
856 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
857 _verify_cset_none, // no cset references, all updated
858 _verify_liveness_disable, // no reliable liveness data anymore
859 _verify_regions_nocset, // no cset regions, trash regions have appeared
860 _verify_gcstate_stable // update refs had cleaned up forwarded objects
861 );
862 }
863
864 void ShenandoahVerifier::verify_after_degenerated() {
865 verify_at_safepoint(
866 "After Degenerated GC",
867 _verify_forwarded_none, // all objects are non-forwarded
868 _verify_marked_complete, // all objects are marked in complete bitmap
869 _verify_cset_none, // no cset references
870 _verify_liveness_disable, // no reliable liveness data anymore
871 _verify_regions_notrash_nocset, // no trash, no cset
872 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
873 );
874 }
875
876 void ShenandoahVerifier::verify_before_traversal() {
877 verify_at_safepoint(
878 "Before Traversal",
879 _verify_forwarded_none, // cannot have forwarded objects
880 _verify_marked_disable, // bitmaps are not relevant before traversal
881 _verify_cset_none, // no cset references before traversal
882 _verify_liveness_disable, // no reliable liveness data anymore
883 _verify_regions_notrash_nocset, // no trash and no cset regions
884 _verify_gcstate_stable // nothing forwarded before traversal
885 );
886 }
887
888 void ShenandoahVerifier::verify_after_traversal() {
889 verify_at_safepoint(
890 "After Traversal",
891 _verify_forwarded_none, // cannot have forwarded objects
892 _verify_marked_complete, // should have complete marking after traversal
893 _verify_cset_none, // no cset references left after traversal
894 _verify_liveness_disable, // liveness data is not collected for new allocations
895 _verify_regions_nocset, // no cset regions, trash regions allowed
896 _verify_gcstate_stable // nothing forwarded after traversal
897 );
898 }
899
900 void ShenandoahVerifier::verify_before_fullgc() {
901 verify_at_safepoint(
902 "Before Full GC",
903 _verify_forwarded_allow, // can have forwarded objects
904 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
905 _verify_cset_disable, // cset might be foobared
906 _verify_liveness_disable, // no reliable liveness data anymore
907 _verify_regions_disable, // no reliable region data here
908 _verify_gcstate_disable // no reliable gcstate data
909 );
910 }
911
912 void ShenandoahVerifier::verify_after_fullgc() {
913 verify_at_safepoint(
914 "After Full GC",
915 _verify_forwarded_none, // all objects are non-forwarded
916 _verify_marked_complete, // all objects are marked in complete bitmap
917 _verify_cset_none, // no cset references
918 _verify_liveness_disable, // no reliable liveness data anymore
919 _verify_regions_notrash_nocset, // no trash, no cset
920 _verify_gcstate_stable // full gc cleaned up everything
921 );
922 }