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 #include "oops/compressedOops.inline.hpp"
38 #include "utilities/align.hpp"
39
40 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
41 #ifdef verify_oop
42 #undef verify_oop
43 #endif
44
45 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
46 private:
47 const char* _phase;
48 ShenandoahVerifier::VerifyOptions _options;
49 ShenandoahVerifierStack* _stack;
50 ShenandoahHeap* _heap;
51 MarkBitMap* _map;
52 ShenandoahLivenessData* _ld;
53 void* _interior_loc;
54 oop _loc;
55
56 public:
57 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
58 const char* phase, ShenandoahVerifier::VerifyOptions options) :
59 _phase(phase),
60 _options(options),
61 _stack(stack),
62 _heap(ShenandoahHeap::heap()),
63 _map(map),
64 _ld(ld),
65 _interior_loc(NULL),
66 _loc(NULL) { }
67
68 private:
69 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
70 if (!test) {
71 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
72 }
73 }
74
75 template <class T>
76 void do_oop_work(T* p) {
77 T o = RawAccess<>::oop_load(p);
78 if (!CompressedOops::is_null(o)) {
79 oop obj = CompressedOops::decode_not_null(o);
80
81 // Single threaded verification can use faster non-atomic stack and bitmap
82 // methods.
83 //
84 // For performance reasons, only fully verify non-marked field values.
85 // We are here when the host object for *p is already marked.
86
87 HeapWord* addr = (HeapWord*) obj;
88 if (_map->par_mark(addr)) {
89 verify_oop_at(p, obj);
90 _stack->push(ShenandoahVerifierTask(obj));
91 }
92 }
93 }
94
95 void verify_oop(oop obj) {
96 // Perform consistency checks with gradually decreasing safety level. This guarantees
97 // that failure report would not try to touch something that was not yet verified to be
98 // safe to process.
99
100 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
101 "oop must be in heap");
102 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
103 "oop must be aligned");
104
105 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
106 Klass* obj_klass = obj->klass_or_null();
107
108 // Verify that obj is not in dead space:
109 {
110 // Do this before touching obj->size()
111 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
112 "Object klass pointer should not be NULL");
113 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
114 "Object klass pointer must go to metaspace");
115
116 HeapWord *obj_addr = (HeapWord *) obj;
117 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
118 "Object start should be within the region");
119
120 if (!obj_reg->is_humongous()) {
121 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
122 "Object end should be within the region");
123 } else {
124 size_t humongous_start = obj_reg->region_number();
125 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
126 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
127 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
128 "Humongous object is in continuation that fits it");
129 }
130 }
131
132 // ------------ obj is safe at this point --------------
133
134 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
135 "Object should be in active region");
136
137 switch (_options._verify_liveness) {
138 case ShenandoahVerifier::_verify_liveness_disable:
139 // skip
140 break;
141 case ShenandoahVerifier::_verify_liveness_complete:
142 Atomic::add((uint) obj->size(), &_ld[obj_reg->region_number()]);
143 // fallthrough for fast failure for un-live regions:
144 case ShenandoahVerifier::_verify_liveness_conservative:
145 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
146 "Object must belong to region with live data");
147 break;
148 default:
149 assert(false, "Unhandled liveness verification");
150 }
151 }
152
153 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
154
155 ShenandoahHeapRegion* fwd_reg = NULL;
156
157 if (obj != fwd) {
158 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
159 "Forwardee must be in heap");
160 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
161 "Forwardee is set");
162 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
163 "Forwardee must be aligned");
164
165 // Do this before touching fwd->size()
166 Klass* fwd_klass = fwd->klass_or_null();
167 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
168 "Forwardee klass pointer should not be NULL");
169 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
170 "Forwardee klass pointer must go to metaspace");
171 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
172 "Forwardee klass pointer must go to metaspace");
173
174 fwd_reg = _heap->heap_region_containing(fwd);
175
176 // Verify that forwardee is not in the dead space:
177 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
178 "Should have no humongous forwardees");
179
180 HeapWord *fwd_addr = (HeapWord *) fwd;
181 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
182 "Forwardee start should be within the region");
183 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
184 "Forwardee end should be within the region");
185
186 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
187 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
188 "Double forwarding");
189 } else {
190 fwd_reg = obj_reg;
191 }
192
193 // ------------ obj and fwd are safe at this point --------------
194
195 switch (_options._verify_marked) {
196 case ShenandoahVerifier::_verify_marked_disable:
197 // skip
198 break;
199 case ShenandoahVerifier::_verify_marked_incomplete:
200 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
201 "Must be marked in incomplete bitmap");
202 break;
203 case ShenandoahVerifier::_verify_marked_complete:
204 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
205 "Must be marked in complete bitmap");
206 break;
207 default:
208 assert(false, "Unhandled mark verification");
209 }
210
211 switch (_options._verify_forwarded) {
212 case ShenandoahVerifier::_verify_forwarded_disable:
213 // skip
214 break;
215 case ShenandoahVerifier::_verify_forwarded_none: {
216 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
217 "Should not be forwarded");
218 break;
219 }
220 case ShenandoahVerifier::_verify_forwarded_allow: {
221 if (obj != fwd) {
222 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
223 "Forwardee should be in another region");
224 }
225 break;
226 }
227 default:
228 assert(false, "Unhandled forwarding verification");
229 }
230
231 switch (_options._verify_cset) {
232 case ShenandoahVerifier::_verify_cset_disable:
233 // skip
234 break;
235 case ShenandoahVerifier::_verify_cset_none:
236 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
237 "Should not have references to collection set");
238 break;
239 case ShenandoahVerifier::_verify_cset_forwarded:
240 if (_heap->in_collection_set(obj)) {
241 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
242 "Object in collection set, should have forwardee");
243 }
244 break;
245 default:
246 assert(false, "Unhandled cset verification");
247 }
248
249 }
250
251 public:
252 /**
253 * Verify object with known interior reference.
254 * @param p interior reference where the object is referenced from; can be off-heap
255 * @param obj verified object
256 */
257 template <class T>
258 void verify_oop_at(T* p, oop obj) {
259 _interior_loc = p;
260 verify_oop(obj);
261 _interior_loc = NULL;
262 }
263
264 /**
265 * Verify object without known interior reference.
266 * Useful when picking up the object at known offset in heap,
267 * but without knowing what objects reference it.
268 * @param obj verified object
269 */
270 void verify_oop_standalone(oop obj) {
271 _interior_loc = NULL;
272 verify_oop(obj);
273 _interior_loc = NULL;
274 }
275
276 /**
277 * Verify oop fields from this object.
278 * @param obj host object for verified fields
279 */
280 void verify_oops_from(oop obj) {
281 _loc = obj;
282 obj->oop_iterate(this);
283 _loc = NULL;
284 }
285
286 virtual void do_oop(oop* p) { do_oop_work(p); }
287 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
288 };
289
290 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
291 private:
292 size_t _used, _committed, _garbage;
293 public:
294 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
295
296 void heap_region_do(ShenandoahHeapRegion* r) {
297 _used += r->used();
298 _garbage += r->garbage();
299 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
300 }
301
302 size_t used() { return _used; }
303 size_t committed() { return _committed; }
304 size_t garbage() { return _garbage; }
305 };
306
307 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
308 private:
309 ShenandoahHeap* _heap;
310 const char* _phase;
311 ShenandoahVerifier::VerifyRegions _regions;
312 public:
313 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
314 _heap(ShenandoahHeap::heap()),
315 _phase(phase),
316 _regions(regions) {};
317
318 void print_failure(ShenandoahHeapRegion* r, const char* label) {
319 ResourceMark rm;
320
321 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
322
323 stringStream ss;
324 r->print_on(&ss);
325 msg.append("%s", ss.as_string());
326
327 report_vm_error(__FILE__, __LINE__, msg.buffer());
328 }
329
330 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
331 if (!test) {
332 print_failure(r, msg);
333 }
334 }
335
336 void heap_region_do(ShenandoahHeapRegion* r) {
337 switch (_regions) {
338 case ShenandoahVerifier::_verify_regions_disable:
339 break;
340 case ShenandoahVerifier::_verify_regions_notrash:
341 verify(r, !r->is_trash(),
342 "Should not have trash regions");
343 break;
344 case ShenandoahVerifier::_verify_regions_nocset:
345 verify(r, !r->is_cset(),
346 "Should not have cset regions");
347 break;
348 case ShenandoahVerifier::_verify_regions_notrash_nocset:
349 verify(r, !r->is_trash(),
350 "Should not have trash regions");
351 verify(r, !r->is_cset(),
352 "Should not have cset regions");
353 break;
354 default:
355 ShouldNotReachHere();
356 }
357
358 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
359 "Capacity should match region size");
360
361 verify(r, r->bottom() <= r->top(),
362 "Region top should not be less than bottom");
363
364 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
365 "Region TAMS should not be less than bottom");
366
367 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
368 "Complete TAMS should not be larger than top");
369
370 verify(r, r->get_live_data_bytes() <= r->capacity(),
371 "Live data cannot be larger than capacity");
372
373 verify(r, r->garbage() <= r->capacity(),
374 "Garbage cannot be larger than capacity");
375
376 verify(r, r->used() <= r->capacity(),
377 "Used cannot be larger than capacity");
378
379 verify(r, r->get_shared_allocs() <= r->capacity(),
380 "Shared alloc count should not be larger than capacity");
381
382 verify(r, r->get_tlab_allocs() <= r->capacity(),
383 "TLAB alloc count should not be larger than capacity");
384
385 verify(r, r->get_gclab_allocs() <= r->capacity(),
386 "GCLAB alloc count should not be larger than capacity");
387
388 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
389 "Accurate accounting: shared + TLAB + GCLAB = used");
390
391 verify(r, !r->is_empty() || !r->has_live(),
392 "Empty regions should not have live data");
393
394 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
395 "Transitional: region flags and collection set agree");
396
397 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
398 "Non-empty regions should have first seqnum set");
399
400 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
401 "Non-empty regions should have first seqnum set to either GC or mutator");
402
403 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
404 "Non-empty regions should have last seqnum set");
405
406 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
407 "Non-empty regions should have last seqnum set to either GC or mutator");
408
409 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
410 "First seqnum should not be greater than last timestamp");
411
412 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
413 "First mutator seqnum should not be greater than last seqnum");
414
415 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
416 "First GC seqnum should not be greater than last seqnum");
417 }
418 };
419
420 class ShenandoahVerifierReachableTask : public AbstractGangTask {
421 private:
422 const char* _label;
423 ShenandoahRootVerifier* _verifier;
424 ShenandoahVerifier::VerifyOptions _options;
425 ShenandoahHeap* _heap;
426 ShenandoahLivenessData* _ld;
427 MarkBitMap* _bitmap;
428 volatile size_t _processed;
429
430 public:
431 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
432 ShenandoahLivenessData* ld,
433 ShenandoahRootVerifier* verifier,
434 const char* label,
435 ShenandoahVerifier::VerifyOptions options) :
436 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
437 _label(label),
438 _verifier(verifier),
439 _options(options),
440 _heap(ShenandoahHeap::heap()),
441 _ld(ld),
442 _bitmap(bitmap),
443 _processed(0) {};
444
445 size_t processed() {
446 return _processed;
447 }
448
449 virtual void work(uint worker_id) {
450 ResourceMark rm;
451 ShenandoahVerifierStack stack;
452
453 // On level 2, we need to only check the roots once.
454 // On level 3, we want to check the roots, and seed the local stack.
455 // It is a lesser evil to accept multiple root scans at level 3, because
456 // extended parallelism would buy us out.
457 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
458 || (ShenandoahVerifyLevel >= 3)) {
459 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
460 ShenandoahMessageBuffer("%s, Roots", _label),
461 _options);
462 if (_heap->unload_classes()) {
463 _verifier->strong_roots_do(&cl);
464 } else {
465 _verifier->roots_do(&cl);
466 }
467 }
468
469 size_t processed = 0;
470
471 if (ShenandoahVerifyLevel >= 3) {
472 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
473 ShenandoahMessageBuffer("%s, Reachable", _label),
474 _options);
475 while (!stack.is_empty()) {
476 processed++;
477 ShenandoahVerifierTask task = stack.pop();
478 cl.verify_oops_from(task.obj());
479 }
480 }
481
482 Atomic::add(processed, &_processed);
483 }
484 };
485
486 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
487 private:
488 const char* _label;
489 ShenandoahVerifier::VerifyOptions _options;
490 ShenandoahHeap *_heap;
491 MarkBitMap* _bitmap;
492 ShenandoahLivenessData* _ld;
493 volatile size_t _claimed;
494 volatile size_t _processed;
495
496 public:
497 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
498 ShenandoahLivenessData* ld,
499 const char* label,
500 ShenandoahVerifier::VerifyOptions options) :
501 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
502 _label(label),
503 _options(options),
504 _heap(ShenandoahHeap::heap()),
505 _bitmap(bitmap),
506 _ld(ld),
507 _claimed(0),
508 _processed(0) {};
509
510 size_t processed() {
511 return _processed;
512 }
513
514 virtual void work(uint worker_id) {
515 ShenandoahVerifierStack stack;
516 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
517 ShenandoahMessageBuffer("%s, Marked", _label),
518 _options);
519
520 while (true) {
521 size_t v = Atomic::add(1u, &_claimed) - 1;
522 if (v < _heap->num_regions()) {
523 ShenandoahHeapRegion* r = _heap->get_region(v);
524 if (!r->is_humongous() && !r->is_trash()) {
525 work_regular(r, stack, cl);
526 } else if (r->is_humongous_start()) {
527 work_humongous(r, stack, cl);
528 }
529 } else {
530 break;
531 }
532 }
533 }
534
535 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
536 size_t processed = 0;
537 HeapWord* obj = r->bottom();
538 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
539 verify_and_follow(obj, stack, cl, &processed);
540 }
541 Atomic::add(processed, &_processed);
542 }
543
544 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
545 size_t processed = 0;
546 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
547 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
548
549 // Bitmaps, before TAMS
550 if (tams > r->bottom()) {
551 HeapWord* start = r->bottom();
552 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
553
554 while (addr < tams) {
555 verify_and_follow(addr, stack, cl, &processed);
556 addr += 1;
557 if (addr < tams) {
558 addr = mark_bit_map->get_next_marked_addr(addr, tams);
559 }
560 }
561 }
562
563 // Size-based, after TAMS
564 {
565 HeapWord* limit = r->top();
566 HeapWord* addr = tams;
567
568 while (addr < limit) {
569 verify_and_follow(addr, stack, cl, &processed);
570 addr += oop(addr)->size();
571 }
572 }
573
574 Atomic::add(processed, &_processed);
575 }
576
577 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
578 if (!_bitmap->par_mark(addr)) return;
579
580 // Verify the object itself:
581 oop obj = oop(addr);
582 cl.verify_oop_standalone(obj);
583
584 // Verify everything reachable from that object too, hopefully realizing
585 // everything was already marked, and never touching further:
586 cl.verify_oops_from(obj);
587 (*processed)++;
588
589 while (!stack.is_empty()) {
590 ShenandoahVerifierTask task = stack.pop();
591 cl.verify_oops_from(task.obj());
592 (*processed)++;
593 }
594 }
595 };
596
597 class VerifyThreadGCState : public ThreadClosure {
598 private:
599 const char* _label;
600 char _expected;
601
602 public:
603 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
604 void do_thread(Thread* t) {
605 char actual = ShenandoahThreadLocalData::gc_state(t);
606 if (actual != _expected) {
607 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
608 }
609 }
610 };
611
612 class ShenandoahGCStateResetter : public StackObj {
613 private:
614 ShenandoahHeap* const _heap;
615 char _gc_state;
616
617 public:
618 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
619 _gc_state = _heap->gc_state();
620 _heap->_gc_state.clear();
621 }
622
623 ~ShenandoahGCStateResetter() {
624 _heap->_gc_state.set(_gc_state);
625 assert(_heap->gc_state() == _gc_state, "Should be restored");
626 }
627 };
628
629 void ShenandoahVerifier::verify_at_safepoint(const char *label,
630 VerifyForwarded forwarded, VerifyMarked marked,
631 VerifyCollectionSet cset,
632 VerifyLiveness liveness, VerifyRegions regions,
633 VerifyGCState gcstate) {
634 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
635 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
636
637 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
638 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
639
640 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
641
642 // GC state checks
643 {
644 char expected = -1;
645 bool enabled;
646 switch (gcstate) {
647 case _verify_gcstate_disable:
648 enabled = false;
649 break;
650 case _verify_gcstate_forwarded:
651 enabled = true;
652 expected = ShenandoahHeap::HAS_FORWARDED;
653 break;
654 case _verify_gcstate_evacuation:
655 enabled = true;
656 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
657 break;
658 case _verify_gcstate_stable:
659 enabled = true;
660 expected = ShenandoahHeap::STABLE;
661 break;
662 default:
663 enabled = false;
664 assert(false, "Unhandled gc-state verification");
665 }
666
667 if (enabled) {
668 char actual = _heap->gc_state();
669 if (actual != expected) {
670 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
671 }
672
673 VerifyThreadGCState vtgcs(label, expected);
674 Threads::java_threads_do(&vtgcs);
675 }
676 }
677
678 // Deactivate barriers temporarily: Verifier wants plain heap accesses
679 ShenandoahGCStateResetter resetter;
680
681 // Heap size checks
682 {
683 ShenandoahHeapLocker lock(_heap->lock());
684
685 ShenandoahCalculateRegionStatsClosure cl;
686 _heap->heap_region_iterate(&cl);
687 size_t heap_used = _heap->used();
688 guarantee(cl.used() == heap_used,
689 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "K, regions-used = " SIZE_FORMAT "K",
690 label, heap_used/K, cl.used()/K);
691
692 size_t heap_committed = _heap->committed();
693 guarantee(cl.committed() == heap_committed,
694 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "K, regions-committed = " SIZE_FORMAT "K",
695 label, heap_committed/K, cl.committed()/K);
696 }
697
698 // Internal heap region checks
699 if (ShenandoahVerifyLevel >= 1) {
700 ShenandoahVerifyHeapRegionClosure cl(label, regions);
701 _heap->heap_region_iterate(&cl);
702 }
703
704 OrderAccess::fence();
705 _heap->make_parsable(false);
706
707 // Allocate temporary bitmap for storing marking wavefront:
708 _verification_bit_map->clear();
709
710 // Allocate temporary array for storing liveness data
711 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
712 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
713
714 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
715
716 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
717 // This verifies what application can see, since it only cares about reachable objects.
718 size_t count_reachable = 0;
719 if (ShenandoahVerifyLevel >= 2) {
720 ShenandoahRootVerifier verifier;
721
722 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
723 _heap->workers()->run_task(&task);
724 count_reachable = task.processed();
725 }
726
727 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
728 // not the application, can see during the region scans. There is no reason to process the objects
729 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
730 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
731 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
732 // version
733
734 size_t count_marked = 0;
735 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
736 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
737 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
738 _heap->workers()->run_task(&task);
739 count_marked = task.processed();
740 } else {
741 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
742 }
743
744 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
745 // marked objects.
746
747 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
748 for (size_t i = 0; i < _heap->num_regions(); i++) {
749 ShenandoahHeapRegion* r = _heap->get_region(i);
750
751 juint verf_live = 0;
752 if (r->is_humongous()) {
753 // For humongous objects, test if start region is marked live, and if so,
754 // all humongous regions in that chain have live data equal to their "used".
755 juint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->region_number()]);
756 if (start_live > 0) {
757 verf_live = (juint)(r->used() / HeapWordSize);
758 }
759 } else {
760 verf_live = OrderAccess::load_acquire(&ld[r->region_number()]);
761 }
762
763 size_t reg_live = r->get_live_data_words();
764 if (reg_live != verf_live) {
765 ResourceMark rm;
766 stringStream ss;
767 r->print_on(&ss);
768 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
769 label, reg_live, verf_live, ss.as_string());
770 }
771 }
772 }
773
774 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
775 label, ShenandoahVerifyLevel, count_reachable, count_marked);
776
777 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
778 }
779
780 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
781 verify_at_safepoint(
782 "Generic Verification",
783 _verify_forwarded_allow, // conservatively allow forwarded
784 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
785 _verify_cset_disable, // cset may be inconsistent
786 _verify_liveness_disable, // no reliable liveness data
787 _verify_regions_disable, // no reliable region data
788 _verify_gcstate_disable // no data about gcstate
789 );
790 }
791
792 void ShenandoahVerifier::verify_before_concmark() {
793 if (_heap->has_forwarded_objects()) {
794 verify_at_safepoint(
795 "Before Mark",
796 _verify_forwarded_allow, // may have forwarded references
797 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
798 _verify_cset_forwarded, // allow forwarded references to cset
799 _verify_liveness_disable, // no reliable liveness data
800 _verify_regions_notrash, // no trash regions
801 _verify_gcstate_forwarded // there are forwarded objects
802 );
803 } else {
804 verify_at_safepoint(
805 "Before Mark",
806 _verify_forwarded_none, // UR should have fixed up
807 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
808 _verify_cset_none, // UR should have fixed this
809 _verify_liveness_disable, // no reliable liveness data
810 _verify_regions_notrash, // no trash regions
811 _verify_gcstate_stable // there are no forwarded objects
812 );
813 }
814 }
815
816 void ShenandoahVerifier::verify_after_concmark() {
817 verify_at_safepoint(
818 "After Mark",
819 _verify_forwarded_none, // no forwarded references
820 _verify_marked_complete, // bitmaps as precise as we can get
821 _verify_cset_none, // no references to cset anymore
822 _verify_liveness_complete, // liveness data must be complete here
823 _verify_regions_disable, // trash regions not yet recycled
824 _verify_gcstate_stable // mark should have stabilized the heap
825 );
826 }
827
828 void ShenandoahVerifier::verify_before_evacuation() {
829 verify_at_safepoint(
830 "Before Evacuation",
831 _verify_forwarded_none, // no forwarded references
832 _verify_marked_complete, // walk over marked objects too
833 _verify_cset_disable, // non-forwarded references to cset expected
834 _verify_liveness_complete, // liveness data must be complete here
835 _verify_regions_disable, // trash regions not yet recycled
836 _verify_gcstate_stable // mark should have stabilized the heap
837 );
838 }
839
840 void ShenandoahVerifier::verify_during_evacuation() {
841 verify_at_safepoint(
842 "During Evacuation",
843 _verify_forwarded_allow, // some forwarded references are allowed
844 _verify_marked_disable, // walk only roots
845 _verify_cset_disable, // some cset references are not forwarded yet
846 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
847 _verify_regions_disable, // trash regions not yet recycled
848 _verify_gcstate_evacuation // evacuation is in progress
849 );
850 }
851
852 void ShenandoahVerifier::verify_after_evacuation() {
853 verify_at_safepoint(
854 "After Evacuation",
855 _verify_forwarded_allow, // objects are still forwarded
856 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
857 _verify_cset_forwarded, // all cset refs are fully forwarded
858 _verify_liveness_disable, // no reliable liveness data anymore
859 _verify_regions_notrash, // trash regions have been recycled already
860 _verify_gcstate_forwarded // evacuation produced some forwarded objects
861 );
862 }
863
864 void ShenandoahVerifier::verify_before_updaterefs() {
865 verify_at_safepoint(
866 "Before Updating References",
867 _verify_forwarded_allow, // forwarded references allowed
868 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
869 _verify_cset_forwarded, // all cset refs are fully forwarded
870 _verify_liveness_disable, // no reliable liveness data anymore
871 _verify_regions_notrash, // trash regions have been recycled already
872 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
873 );
874 }
875
876 void ShenandoahVerifier::verify_after_updaterefs() {
877 verify_at_safepoint(
878 "After Updating References",
879 _verify_forwarded_none, // no forwarded references
880 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
881 _verify_cset_none, // no cset references, all updated
882 _verify_liveness_disable, // no reliable liveness data anymore
883 _verify_regions_nocset, // no cset regions, trash regions have appeared
884 _verify_gcstate_stable // update refs had cleaned up forwarded objects
885 );
886 }
887
888 void ShenandoahVerifier::verify_after_degenerated() {
889 verify_at_safepoint(
890 "After Degenerated GC",
891 _verify_forwarded_none, // all objects are non-forwarded
892 _verify_marked_complete, // all objects are marked in complete bitmap
893 _verify_cset_none, // no cset references
894 _verify_liveness_disable, // no reliable liveness data anymore
895 _verify_regions_notrash_nocset, // no trash, no cset
896 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
897 );
898 }
899
900 void ShenandoahVerifier::verify_before_traversal() {
901 verify_at_safepoint(
902 "Before Traversal",
903 _verify_forwarded_none, // cannot have forwarded objects
904 _verify_marked_disable, // bitmaps are not relevant before traversal
905 _verify_cset_none, // no cset references before traversal
906 _verify_liveness_disable, // no reliable liveness data anymore
907 _verify_regions_notrash_nocset, // no trash and no cset regions
908 _verify_gcstate_stable // nothing forwarded before traversal
909 );
910 }
911
912 void ShenandoahVerifier::verify_after_traversal() {
913 verify_at_safepoint(
914 "After Traversal",
915 _verify_forwarded_none, // cannot have forwarded objects
916 _verify_marked_complete, // should have complete marking after traversal
917 _verify_cset_none, // no cset references left after traversal
918 _verify_liveness_disable, // liveness data is not collected for new allocations
919 _verify_regions_nocset, // no cset regions, trash regions allowed
920 _verify_gcstate_stable // nothing forwarded after traversal
921 );
922 }
923
924 void ShenandoahVerifier::verify_before_fullgc() {
925 verify_at_safepoint(
926 "Before Full GC",
927 _verify_forwarded_allow, // can have forwarded objects
928 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
929 _verify_cset_disable, // cset might be foobared
930 _verify_liveness_disable, // no reliable liveness data anymore
931 _verify_regions_disable, // no reliable region data here
932 _verify_gcstate_disable // no reliable gcstate data
933 );
934 }
935
936 void ShenandoahVerifier::verify_after_fullgc() {
937 verify_at_safepoint(
938 "After Full GC",
939 _verify_forwarded_none, // all objects are non-forwarded
940 _verify_marked_complete, // all objects are marked in complete bitmap
941 _verify_cset_none, // no cset references
942 _verify_liveness_disable, // no reliable liveness data anymore
943 _verify_regions_notrash_nocset, // no trash, no cset
944 _verify_gcstate_stable // full gc cleaned up everything
945 );
946 }
947
948 class ShenandoahVerifyNoForwared : public OopClosure {
949 private:
950 template <class T>
951 void do_oop_work(T* p) {
952 T o = RawAccess<>::oop_load(p);
953 if (!CompressedOops::is_null(o)) {
954 oop obj = CompressedOops::decode_not_null(o);
955 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
956 if (obj != fwd) {
957 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
958 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
959 }
960 }
961 }
962
963 public:
964 void do_oop(narrowOop* p) { do_oop_work(p); }
965 void do_oop(oop* p) { do_oop_work(p); }
966 };
967
968 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
969 private:
970 template <class T>
971 void do_oop_work(T* p) {
972 T o = RawAccess<>::oop_load(p);
973 if (!CompressedOops::is_null(o)) {
974 oop obj = CompressedOops::decode_not_null(o);
975 ShenandoahHeap* heap = ShenandoahHeap::heap_no_check();
976
977 if (!heap->marking_context()->is_marked(obj)) {
978 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
979 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
980 }
981
982 if (heap->in_collection_set(obj)) {
983 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
984 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
985 }
986
987 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
988 if (obj != fwd) {
989 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
990 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
991 }
992 }
993 }
994
995 public:
996 void do_oop(narrowOop* p) { do_oop_work(p); }
997 void do_oop(oop* p) { do_oop_work(p); }
998 };
999
1000 void ShenandoahVerifier::verify_roots_in_to_space() {
1001 ShenandoahRootVerifier verifier;
1002 ShenandoahVerifyInToSpaceClosure cl;
1003 verifier.oops_do(&cl);
1004 }
1005
1006 void ShenandoahVerifier::verify_roots_no_forwarded() {
1007 ShenandoahRootVerifier verifier;
1008 ShenandoahVerifyNoForwared cl;
1009 verifier.oops_do(&cl);
1010 }
1011
1012 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
1013 ShenandoahRootVerifier verifier;
1014 verifier.excludes(types);
1015 ShenandoahVerifyNoForwared cl;
1016 verifier.oops_do(&cl);
1017 }