1 /*
2 * Copyright (c) 2017, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
30 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
33 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "gc/shenandoah/shenandoahVerifier.hpp"
36 #include "memory/allocation.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/compressedOops.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/orderAccess.hpp"
42 #include "utilities/align.hpp"
43
44 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
45 #ifdef verify_oop
46 #undef verify_oop
47 #endif
48
49 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
50 private:
51 const char* _phase;
52 ShenandoahVerifier::VerifyOptions _options;
53 ShenandoahVerifierStack* _stack;
54 ShenandoahHeap* _heap;
55 MarkBitMap* _map;
56 ShenandoahLivenessData* _ld;
57 void* _interior_loc;
58 oop _loc;
59
60 public:
61 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
62 const char* phase, ShenandoahVerifier::VerifyOptions options) :
63 _phase(phase),
64 _options(options),
65 _stack(stack),
66 _heap(ShenandoahHeap::heap()),
67 _map(map),
68 _ld(ld),
69 _interior_loc(NULL),
70 _loc(NULL) { }
71
72 private:
73 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
74 if (!test) {
75 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
76 }
77 }
78
79 template <class T>
80 void do_oop_work(T* p) {
81 T o = RawAccess<>::oop_load(p);
82 if (!CompressedOops::is_null(o)) {
83 oop obj = CompressedOops::decode_not_null(o);
84
85 // Single threaded verification can use faster non-atomic stack and bitmap
86 // methods.
87 //
88 // For performance reasons, only fully verify non-marked field values.
89 // We are here when the host object for *p is already marked.
90
91 HeapWord* addr = cast_from_oop<HeapWord*>(obj);
92 if (_map->par_mark(addr)) {
93 verify_oop_at(p, obj);
94 _stack->push(ShenandoahVerifierTask(obj));
95 }
96 }
97 }
98
99 void verify_oop(oop obj) {
100 // Perform consistency checks with gradually decreasing safety level. This guarantees
101 // that failure report would not try to touch something that was not yet verified to be
102 // safe to process.
103
104 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
105 "oop must be in heap");
106 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
107 "oop must be aligned");
108
109 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
110 Klass* obj_klass = obj->klass_or_null();
111
112 // Verify that obj is not in dead space:
113 {
114 // Do this before touching obj->size()
115 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
116 "Object klass pointer should not be NULL");
117 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
118 "Object klass pointer must go to metaspace");
119
120 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
121 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
122 "Object start should be within the region");
123
124 if (!obj_reg->is_humongous()) {
125 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
126 "Object end should be within the region");
127 } else {
128 size_t humongous_start = obj_reg->region_number();
129 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
130 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
131 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
132 "Humongous object is in continuation that fits it");
133 }
134 }
135
136 // ------------ obj is safe at this point --------------
137
138 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
139 "Object should be in active region");
140
141 switch (_options._verify_liveness) {
142 case ShenandoahVerifier::_verify_liveness_disable:
143 // skip
144 break;
145 case ShenandoahVerifier::_verify_liveness_complete:
146 Atomic::add(&_ld[obj_reg->region_number()], (uint) obj->size());
147 // fallthrough for fast failure for un-live regions:
148 case ShenandoahVerifier::_verify_liveness_conservative:
149 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
150 "Object must belong to region with live data");
151 break;
152 default:
153 assert(false, "Unhandled liveness verification");
154 }
155 }
156
157 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
158
159 ShenandoahHeapRegion* fwd_reg = NULL;
160
161 if (obj != fwd) {
162 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
163 "Forwardee must be in heap");
164 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
165 "Forwardee is set");
166 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
167 "Forwardee must be aligned");
168
169 // Do this before touching fwd->size()
170 Klass* fwd_klass = fwd->klass_or_null();
171 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
172 "Forwardee klass pointer should not be NULL");
173 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
174 "Forwardee klass pointer must go to metaspace");
175 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
176 "Forwardee klass pointer must go to metaspace");
177
178 fwd_reg = _heap->heap_region_containing(fwd);
179
180 // Verify that forwardee is not in the dead space:
181 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
182 "Should have no humongous forwardees");
183
184 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
185 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
186 "Forwardee start should be within the region");
187 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
188 "Forwardee end should be within the region");
189
190 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
191 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
192 "Double forwarding");
193 } else {
194 fwd_reg = obj_reg;
195 }
196
197 // ------------ obj and fwd are safe at this point --------------
198
199 switch (_options._verify_marked) {
200 case ShenandoahVerifier::_verify_marked_disable:
201 // skip
202 break;
203 case ShenandoahVerifier::_verify_marked_incomplete:
204 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
205 "Must be marked in incomplete bitmap");
206 break;
207 case ShenandoahVerifier::_verify_marked_complete:
208 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
209 "Must be marked in complete bitmap");
210 break;
211 default:
212 assert(false, "Unhandled mark verification");
213 }
214
215 switch (_options._verify_forwarded) {
216 case ShenandoahVerifier::_verify_forwarded_disable:
217 // skip
218 break;
219 case ShenandoahVerifier::_verify_forwarded_none: {
220 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
221 "Should not be forwarded");
222 break;
223 }
224 case ShenandoahVerifier::_verify_forwarded_allow: {
225 if (obj != fwd) {
226 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
227 "Forwardee should be in another region");
228 }
229 break;
230 }
231 default:
232 assert(false, "Unhandled forwarding verification");
233 }
234
235 switch (_options._verify_cset) {
236 case ShenandoahVerifier::_verify_cset_disable:
237 // skip
238 break;
239 case ShenandoahVerifier::_verify_cset_none:
240 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
241 "Should not have references to collection set");
242 break;
243 case ShenandoahVerifier::_verify_cset_forwarded:
244 if (_heap->in_collection_set(obj)) {
245 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
246 "Object in collection set, should have forwardee");
247 }
248 break;
249 default:
250 assert(false, "Unhandled cset verification");
251 }
252
253 }
254
255 public:
256 /**
257 * Verify object with known interior reference.
258 * @param p interior reference where the object is referenced from; can be off-heap
259 * @param obj verified object
260 */
261 template <class T>
262 void verify_oop_at(T* p, oop obj) {
263 _interior_loc = p;
264 verify_oop(obj);
265 _interior_loc = NULL;
266 }
267
268 /**
269 * Verify object without known interior reference.
270 * Useful when picking up the object at known offset in heap,
271 * but without knowing what objects reference it.
272 * @param obj verified object
273 */
274 void verify_oop_standalone(oop obj) {
275 _interior_loc = NULL;
276 verify_oop(obj);
277 _interior_loc = NULL;
278 }
279
280 /**
281 * Verify oop fields from this object.
282 * @param obj host object for verified fields
283 */
284 void verify_oops_from(oop obj) {
285 _loc = obj;
286 obj->oop_iterate(this);
287 _loc = NULL;
288 }
289
290 virtual void do_oop(oop* p) { do_oop_work(p); }
291 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
292 };
293
294 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
295 private:
296 size_t _used, _committed, _garbage;
297 public:
298 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
299
300 void heap_region_do(ShenandoahHeapRegion* r) {
301 _used += r->used();
302 _garbage += r->garbage();
303 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
304 }
305
306 size_t used() { return _used; }
307 size_t committed() { return _committed; }
308 size_t garbage() { return _garbage; }
309 };
310
311 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
312 private:
313 ShenandoahHeap* _heap;
314 const char* _phase;
315 ShenandoahVerifier::VerifyRegions _regions;
316 public:
317 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
318 _heap(ShenandoahHeap::heap()),
319 _phase(phase),
320 _regions(regions) {};
321
322 void print_failure(ShenandoahHeapRegion* r, const char* label) {
323 ResourceMark rm;
324
325 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
326
327 stringStream ss;
328 r->print_on(&ss);
329 msg.append("%s", ss.as_string());
330
331 report_vm_error(__FILE__, __LINE__, msg.buffer());
332 }
333
334 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
335 if (!test) {
336 print_failure(r, msg);
337 }
338 }
339
340 void heap_region_do(ShenandoahHeapRegion* r) {
341 switch (_regions) {
342 case ShenandoahVerifier::_verify_regions_disable:
343 break;
344 case ShenandoahVerifier::_verify_regions_notrash:
345 verify(r, !r->is_trash(),
346 "Should not have trash regions");
347 break;
348 case ShenandoahVerifier::_verify_regions_nocset:
349 verify(r, !r->is_cset(),
350 "Should not have cset regions");
351 break;
352 case ShenandoahVerifier::_verify_regions_notrash_nocset:
353 verify(r, !r->is_trash(),
354 "Should not have trash regions");
355 verify(r, !r->is_cset(),
356 "Should not have cset regions");
357 break;
358 default:
359 ShouldNotReachHere();
360 }
361
362 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
363 "Capacity should match region size");
364
365 verify(r, r->bottom() <= r->top(),
366 "Region top should not be less than bottom");
367
368 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
369 "Region TAMS should not be less than bottom");
370
371 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
372 "Complete TAMS should not be larger than top");
373
374 verify(r, r->get_live_data_bytes() <= r->capacity(),
375 "Live data cannot be larger than capacity");
376
377 verify(r, r->garbage() <= r->capacity(),
378 "Garbage cannot be larger than capacity");
379
380 verify(r, r->used() <= r->capacity(),
381 "Used cannot be larger than capacity");
382
383 verify(r, r->get_shared_allocs() <= r->capacity(),
384 "Shared alloc count should not be larger than capacity");
385
386 verify(r, r->get_tlab_allocs() <= r->capacity(),
387 "TLAB alloc count should not be larger than capacity");
388
389 verify(r, r->get_gclab_allocs() <= r->capacity(),
390 "GCLAB alloc count should not be larger than capacity");
391
392 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
393 "Accurate accounting: shared + TLAB + GCLAB = used");
394
395 verify(r, !r->is_empty() || !r->has_live(),
396 "Empty regions should not have live data");
397
398 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
399 "Transitional: region flags and collection set agree");
400
401 verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,
402 "Non-empty regions should have first seqnum set");
403
404 verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),
405 "Non-empty regions should have first seqnum set to either GC or mutator");
406
407 verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,
408 "Non-empty regions should have last seqnum set");
409
410 verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),
411 "Non-empty regions should have last seqnum set to either GC or mutator");
412
413 verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),
414 "First seqnum should not be greater than last timestamp");
415
416 verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),
417 "First mutator seqnum should not be greater than last seqnum");
418
419 verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),
420 "First GC seqnum should not be greater than last seqnum");
421 }
422 };
423
424 class ShenandoahVerifierReachableTask : public AbstractGangTask {
425 private:
426 const char* _label;
427 ShenandoahRootVerifier* _verifier;
428 ShenandoahVerifier::VerifyOptions _options;
429 ShenandoahHeap* _heap;
430 ShenandoahLivenessData* _ld;
431 MarkBitMap* _bitmap;
432 volatile size_t _processed;
433
434 public:
435 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
436 ShenandoahLivenessData* ld,
437 ShenandoahRootVerifier* verifier,
438 const char* label,
439 ShenandoahVerifier::VerifyOptions options) :
440 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
441 _label(label),
442 _verifier(verifier),
443 _options(options),
444 _heap(ShenandoahHeap::heap()),
445 _ld(ld),
446 _bitmap(bitmap),
447 _processed(0) {};
448
449 size_t processed() {
450 return _processed;
451 }
452
453 virtual void work(uint worker_id) {
454 ResourceMark rm;
455 ShenandoahVerifierStack stack;
456
457 // On level 2, we need to only check the roots once.
458 // On level 3, we want to check the roots, and seed the local stack.
459 // It is a lesser evil to accept multiple root scans at level 3, because
460 // extended parallelism would buy us out.
461 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
462 || (ShenandoahVerifyLevel >= 3)) {
463 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
464 ShenandoahMessageBuffer("%s, Roots", _label),
465 _options);
466 if (_heap->unload_classes()) {
467 _verifier->strong_roots_do(&cl);
468 } else {
469 _verifier->roots_do(&cl);
470 }
471 }
472
473 size_t processed = 0;
474
475 if (ShenandoahVerifyLevel >= 3) {
476 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
477 ShenandoahMessageBuffer("%s, Reachable", _label),
478 _options);
479 while (!stack.is_empty()) {
480 processed++;
481 ShenandoahVerifierTask task = stack.pop();
482 cl.verify_oops_from(task.obj());
483 }
484 }
485
486 Atomic::add(&_processed, processed);
487 }
488 };
489
490 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
491 private:
492 const char* _label;
493 ShenandoahVerifier::VerifyOptions _options;
494 ShenandoahHeap *_heap;
495 MarkBitMap* _bitmap;
496 ShenandoahLivenessData* _ld;
497 volatile size_t _claimed;
498 volatile size_t _processed;
499
500 public:
501 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
502 ShenandoahLivenessData* ld,
503 const char* label,
504 ShenandoahVerifier::VerifyOptions options) :
505 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
506 _label(label),
507 _options(options),
508 _heap(ShenandoahHeap::heap()),
509 _bitmap(bitmap),
510 _ld(ld),
511 _claimed(0),
512 _processed(0) {};
513
514 size_t processed() {
515 return _processed;
516 }
517
518 virtual void work(uint worker_id) {
519 ShenandoahVerifierStack stack;
520 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
521 ShenandoahMessageBuffer("%s, Marked", _label),
522 _options);
523
524 while (true) {
525 size_t v = Atomic::fetch_and_add(&_claimed, 1u);
526 if (v < _heap->num_regions()) {
527 ShenandoahHeapRegion* r = _heap->get_region(v);
528 if (!r->is_humongous() && !r->is_trash()) {
529 work_regular(r, stack, cl);
530 } else if (r->is_humongous_start()) {
531 work_humongous(r, stack, cl);
532 }
533 } else {
534 break;
535 }
536 }
537 }
538
539 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
540 size_t processed = 0;
541 HeapWord* obj = r->bottom();
542 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
543 verify_and_follow(obj, stack, cl, &processed);
544 }
545 Atomic::add(&_processed, processed);
546 }
547
548 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
549 size_t processed = 0;
550 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
551 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
552
553 // Bitmaps, before TAMS
554 if (tams > r->bottom()) {
555 HeapWord* start = r->bottom();
556 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
557
558 while (addr < tams) {
559 verify_and_follow(addr, stack, cl, &processed);
560 addr += 1;
561 if (addr < tams) {
562 addr = mark_bit_map->get_next_marked_addr(addr, tams);
563 }
564 }
565 }
566
567 // Size-based, after TAMS
568 {
569 HeapWord* limit = r->top();
570 HeapWord* addr = tams;
571
572 while (addr < limit) {
573 verify_and_follow(addr, stack, cl, &processed);
574 addr += oop(addr)->size();
575 }
576 }
577
578 Atomic::add(&_processed, processed);
579 }
580
581 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
582 if (!_bitmap->par_mark(addr)) return;
583
584 // Verify the object itself:
585 oop obj = oop(addr);
586 cl.verify_oop_standalone(obj);
587
588 // Verify everything reachable from that object too, hopefully realizing
589 // everything was already marked, and never touching further:
590 cl.verify_oops_from(obj);
591 (*processed)++;
592
593 while (!stack.is_empty()) {
594 ShenandoahVerifierTask task = stack.pop();
595 cl.verify_oops_from(task.obj());
596 (*processed)++;
597 }
598 }
599 };
600
601 class VerifyThreadGCState : public ThreadClosure {
602 private:
603 const char* _label;
604 char _expected;
605
606 public:
607 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
608 void do_thread(Thread* t) {
609 char actual = ShenandoahThreadLocalData::gc_state(t);
610 if (actual != _expected) {
611 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
612 }
613 }
614 };
615
616 class ShenandoahGCStateResetter : public StackObj {
617 private:
618 ShenandoahHeap* const _heap;
619 char _gc_state;
620
621 public:
622 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
623 _gc_state = _heap->gc_state();
624 _heap->_gc_state.clear();
625 }
626
627 ~ShenandoahGCStateResetter() {
628 _heap->_gc_state.set(_gc_state);
629 assert(_heap->gc_state() == _gc_state, "Should be restored");
630 }
631 };
632
633 void ShenandoahVerifier::verify_at_safepoint(const char *label,
634 VerifyForwarded forwarded, VerifyMarked marked,
635 VerifyCollectionSet cset,
636 VerifyLiveness liveness, VerifyRegions regions,
637 VerifyGCState gcstate,
638 VerifyWeakRoots weak_roots) {
639 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
640 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
641
642 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
643 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
644
645 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
646
647 // GC state checks
648 {
649 char expected = -1;
650 bool enabled;
651 switch (gcstate) {
652 case _verify_gcstate_disable:
653 enabled = false;
654 break;
655 case _verify_gcstate_forwarded:
656 enabled = true;
657 expected = ShenandoahHeap::HAS_FORWARDED;
658 break;
659 case _verify_gcstate_evacuation:
660 enabled = true;
661 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
662 break;
663 case _verify_gcstate_stable:
664 enabled = true;
665 expected = ShenandoahHeap::STABLE;
666 break;
667 default:
668 enabled = false;
669 assert(false, "Unhandled gc-state verification");
670 }
671
672 if (enabled) {
673 char actual = _heap->gc_state();
674 if (actual != expected) {
675 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
676 }
677
678 VerifyThreadGCState vtgcs(label, expected);
679 Threads::java_threads_do(&vtgcs);
680 }
681 }
682
683 // Deactivate barriers temporarily: Verifier wants plain heap accesses
684 ShenandoahGCStateResetter resetter;
685
686 // Heap size checks
687 {
688 ShenandoahHeapLocker lock(_heap->lock());
689
690 ShenandoahCalculateRegionStatsClosure cl;
691 _heap->heap_region_iterate(&cl);
692 size_t heap_used = _heap->used();
693 guarantee(cl.used() == heap_used,
694 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
695 label,
696 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
697 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
698
699 size_t heap_committed = _heap->committed();
700 guarantee(cl.committed() == heap_committed,
701 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
702 label,
703 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
704 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
705 }
706
707 // Internal heap region checks
708 if (ShenandoahVerifyLevel >= 1) {
709 ShenandoahVerifyHeapRegionClosure cl(label, regions);
710 _heap->heap_region_iterate(&cl);
711 }
712
713 OrderAccess::fence();
714 _heap->make_parsable(false);
715
716 // Allocate temporary bitmap for storing marking wavefront:
717 _verification_bit_map->clear();
718
719 // Allocate temporary array for storing liveness data
720 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
721 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
722
723 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
724
725 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
726 // This verifies what application can see, since it only cares about reachable objects.
727 size_t count_reachable = 0;
728 if (ShenandoahVerifyLevel >= 2) {
729 ShenandoahRootVerifier verifier;
730 switch (weak_roots) {
731 case _verify_serial_weak_roots:
732 verifier.excludes(ShenandoahRootVerifier::ConcurrentWeakRoots);
733 break;
734 case _verify_concurrent_weak_roots:
735 verifier.excludes(ShenandoahRootVerifier::SerialWeakRoots);
736 break;
737 case _verify_all_weak_roots:
738 break;
739 default:
740 ShouldNotReachHere();
741 }
742
743 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
744 _heap->workers()->run_task(&task);
745 count_reachable = task.processed();
746 }
747
748 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
749 // not the application, can see during the region scans. There is no reason to process the objects
750 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
751 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
752 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
753 // version
754
755 size_t count_marked = 0;
756 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
757 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
758 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
759 _heap->workers()->run_task(&task);
760 count_marked = task.processed();
761 } else {
762 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
763 }
764
765 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
766 // marked objects.
767
768 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
769 for (size_t i = 0; i < _heap->num_regions(); i++) {
770 ShenandoahHeapRegion* r = _heap->get_region(i);
771
772 juint verf_live = 0;
773 if (r->is_humongous()) {
774 // For humongous objects, test if start region is marked live, and if so,
775 // all humongous regions in that chain have live data equal to their "used".
776 juint start_live = Atomic::load_acquire(&ld[r->humongous_start_region()->region_number()]);
777 if (start_live > 0) {
778 verf_live = (juint)(r->used() / HeapWordSize);
779 }
780 } else {
781 verf_live = Atomic::load_acquire(&ld[r->region_number()]);
782 }
783
784 size_t reg_live = r->get_live_data_words();
785 if (reg_live != verf_live) {
786 ResourceMark rm;
787 stringStream ss;
788 r->print_on(&ss);
789 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
790 label, reg_live, verf_live, ss.as_string());
791 }
792 }
793 }
794
795 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
796 label, ShenandoahVerifyLevel, count_reachable, count_marked);
797
798 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
799 }
800
801 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
802 verify_at_safepoint(
803 "Generic Verification",
804 _verify_forwarded_allow, // conservatively allow forwarded
805 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
806 _verify_cset_disable, // cset may be inconsistent
807 _verify_liveness_disable, // no reliable liveness data
808 _verify_regions_disable, // no reliable region data
809 _verify_gcstate_disable, // no data about gcstate
810 _verify_all_weak_roots
811 );
812 }
813
814 void ShenandoahVerifier::verify_before_concmark() {
815 if (_heap->has_forwarded_objects()) {
816 verify_at_safepoint(
817 "Before Mark",
818 _verify_forwarded_allow, // may have forwarded references
819 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
820 _verify_cset_forwarded, // allow forwarded references to cset
821 _verify_liveness_disable, // no reliable liveness data
822 _verify_regions_notrash, // no trash regions
823 _verify_gcstate_forwarded, // there are forwarded objects
824 _verify_all_weak_roots
825 );
826 } else {
827 verify_at_safepoint(
828 "Before Mark",
829 _verify_forwarded_none, // UR should have fixed up
830 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
831 _verify_cset_none, // UR should have fixed this
832 _verify_liveness_disable, // no reliable liveness data
833 _verify_regions_notrash, // no trash regions
834 _verify_gcstate_stable, // there are no forwarded objects
835 _verify_all_weak_roots
836 );
837 }
838 }
839
840 void ShenandoahVerifier::verify_after_concmark() {
841 verify_at_safepoint(
842 "After Mark",
843 _verify_forwarded_none, // no forwarded references
844 _verify_marked_complete, // bitmaps as precise as we can get
845 _verify_cset_none, // no references to cset anymore
846 _verify_liveness_complete, // liveness data must be complete here
847 _verify_regions_disable, // trash regions not yet recycled
848 _verify_gcstate_stable, // mark should have stabilized the heap
849 _verify_all_weak_roots
850 );
851 }
852
853 void ShenandoahVerifier::verify_before_evacuation() {
854 // Concurrent weak roots are evacuated during concurrent phase
855 VerifyWeakRoots verify_weak_roots = ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() ?
856 _verify_serial_weak_roots :
857 _verify_all_weak_roots;
858
859 verify_at_safepoint(
860 "Before Evacuation",
861 _verify_forwarded_none, // no forwarded references
862 _verify_marked_complete, // walk over marked objects too
863 _verify_cset_disable, // non-forwarded references to cset expected
864 _verify_liveness_complete, // liveness data must be complete here
865 _verify_regions_disable, // trash regions not yet recycled
866 _verify_gcstate_stable, // mark should have stabilized the heap
867 verify_weak_roots
868 );
869 }
870
871 void ShenandoahVerifier::verify_during_evacuation() {
872 // Concurrent weak roots are evacuated during concurrent phase
873 VerifyWeakRoots verify_weak_roots = ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() ?
874 _verify_serial_weak_roots :
875 _verify_all_weak_roots;
876
877 verify_at_safepoint(
878 "During Evacuation",
879 _verify_forwarded_allow, // some forwarded references are allowed
880 _verify_marked_disable, // walk only roots
881 _verify_cset_disable, // some cset references are not forwarded yet
882 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
883 _verify_regions_disable, // trash regions not yet recycled
884 _verify_gcstate_evacuation, // evacuation is in progress
885 verify_weak_roots
886 );
887 }
888
889 void ShenandoahVerifier::verify_after_evacuation() {
890 verify_at_safepoint(
891 "After Evacuation",
892 _verify_forwarded_allow, // objects are still forwarded
893 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
894 _verify_cset_forwarded, // all cset refs are fully forwarded
895 _verify_liveness_disable, // no reliable liveness data anymore
896 _verify_regions_notrash, // trash regions have been recycled already
897 _verify_gcstate_forwarded, // evacuation produced some forwarded objects
898 _verify_all_weak_roots
899 );
900 }
901
902 void ShenandoahVerifier::verify_before_updaterefs() {
903 verify_at_safepoint(
904 "Before Updating References",
905 _verify_forwarded_allow, // forwarded references allowed
906 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
907 _verify_cset_forwarded, // all cset refs are fully forwarded
908 _verify_liveness_disable, // no reliable liveness data anymore
909 _verify_regions_notrash, // trash regions have been recycled already
910 _verify_gcstate_forwarded, // evacuation should have produced some forwarded objects
911 _verify_all_weak_roots
912 );
913 }
914
915 void ShenandoahVerifier::verify_after_updaterefs() {
916 verify_at_safepoint(
917 "After Updating References",
918 _verify_forwarded_none, // no forwarded references
919 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
920 _verify_cset_none, // no cset references, all updated
921 _verify_liveness_disable, // no reliable liveness data anymore
922 _verify_regions_nocset, // no cset regions, trash regions have appeared
923 _verify_gcstate_stable, // update refs had cleaned up forwarded objects
924 _verify_all_weak_roots
925 );
926 }
927
928 void ShenandoahVerifier::verify_after_degenerated() {
929 verify_at_safepoint(
930 "After Degenerated GC",
931 _verify_forwarded_none, // all objects are non-forwarded
932 _verify_marked_complete, // all objects are marked in complete bitmap
933 _verify_cset_none, // no cset references
934 _verify_liveness_disable, // no reliable liveness data anymore
935 _verify_regions_notrash_nocset, // no trash, no cset
936 _verify_gcstate_stable, // degenerated refs had cleaned up forwarded objects
937 _verify_all_weak_roots
938 );
939 }
940
941 void ShenandoahVerifier::verify_before_traversal() {
942 verify_at_safepoint(
943 "Before Traversal",
944 _verify_forwarded_none, // cannot have forwarded objects
945 _verify_marked_disable, // bitmaps are not relevant before traversal
946 _verify_cset_none, // no cset references before traversal
947 _verify_liveness_disable, // no reliable liveness data anymore
948 _verify_regions_notrash_nocset, // no trash and no cset regions
949 _verify_gcstate_stable, // nothing forwarded before traversal
950 _verify_all_weak_roots
951 );
952 }
953
954 void ShenandoahVerifier::verify_after_traversal() {
955 verify_at_safepoint(
956 "After Traversal",
957 _verify_forwarded_none, // cannot have forwarded objects
958 _verify_marked_complete, // should have complete marking after traversal
959 _verify_cset_none, // no cset references left after traversal
960 _verify_liveness_disable, // liveness data is not collected for new allocations
961 _verify_regions_nocset, // no cset regions, trash regions allowed
962 _verify_gcstate_stable, // nothing forwarded after traversal
963 _verify_all_weak_roots
964 );
965 }
966
967 void ShenandoahVerifier::verify_before_fullgc() {
968 verify_at_safepoint(
969 "Before Full GC",
970 _verify_forwarded_allow, // can have forwarded objects
971 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
972 _verify_cset_disable, // cset might be foobared
973 _verify_liveness_disable, // no reliable liveness data anymore
974 _verify_regions_disable, // no reliable region data here
975 _verify_gcstate_disable, // no reliable gcstate data
976 _verify_all_weak_roots
977 );
978 }
979
980 void ShenandoahVerifier::verify_after_fullgc() {
981 verify_at_safepoint(
982 "After Full GC",
983 _verify_forwarded_none, // all objects are non-forwarded
984 _verify_marked_complete, // all objects are marked in complete bitmap
985 _verify_cset_none, // no cset references
986 _verify_liveness_disable, // no reliable liveness data anymore
987 _verify_regions_notrash_nocset, // no trash, no cset
988 _verify_gcstate_stable, // full gc cleaned up everything
989 _verify_all_weak_roots
990 );
991 }
992
993 class ShenandoahVerifyNoForwared : public OopClosure {
994 private:
995 template <class T>
996 void do_oop_work(T* p) {
997 T o = RawAccess<>::oop_load(p);
998 if (!CompressedOops::is_null(o)) {
999 oop obj = CompressedOops::decode_not_null(o);
1000 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1001 if (obj != fwd) {
1002 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1003 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1004 }
1005 }
1006 }
1007
1008 public:
1009 void do_oop(narrowOop* p) { do_oop_work(p); }
1010 void do_oop(oop* p) { do_oop_work(p); }
1011 };
1012
1013 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
1014 private:
1015 template <class T>
1016 void do_oop_work(T* p) {
1017 T o = RawAccess<>::oop_load(p);
1018 if (!CompressedOops::is_null(o)) {
1019 oop obj = CompressedOops::decode_not_null(o);
1020 ShenandoahHeap* heap = ShenandoahHeap::heap_no_check();
1021
1022 if (!heap->marking_context()->is_marked(obj)) {
1023 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1024 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1025 }
1026
1027 if (heap->in_collection_set(obj)) {
1028 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1029 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1030 }
1031
1032 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1033 if (obj != fwd) {
1034 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
1035 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1036 }
1037 }
1038 }
1039
1040 public:
1041 void do_oop(narrowOop* p) { do_oop_work(p); }
1042 void do_oop(oop* p) { do_oop_work(p); }
1043 };
1044
1045 void ShenandoahVerifier::verify_roots_in_to_space() {
1046 ShenandoahRootVerifier verifier;
1047 ShenandoahVerifyInToSpaceClosure cl;
1048 verifier.oops_do(&cl);
1049 }
1050
1051 void ShenandoahVerifier::verify_roots_in_to_space_except(ShenandoahRootVerifier::RootTypes types) {
1052 ShenandoahRootVerifier verifier;
1053 verifier.excludes(types);
1054 ShenandoahVerifyInToSpaceClosure cl;
1055 verifier.oops_do(&cl);
1056 }
1057
1058 void ShenandoahVerifier::verify_roots_no_forwarded() {
1059 ShenandoahRootVerifier verifier;
1060 ShenandoahVerifyNoForwared cl;
1061 verifier.oops_do(&cl);
1062 }
1063
1064 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
1065 ShenandoahRootVerifier verifier;
1066 verifier.excludes(types);
1067 ShenandoahVerifyNoForwared cl;
1068 verifier.oops_do(&cl);
1069 }