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/shenandoahHeapRegion.inline.hpp"
33 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
34 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
35 #include "gc/shenandoah/shenandoahUtils.hpp"
36 #include "gc/shenandoah/shenandoahVerifier.hpp"
37 #include "memory/allocation.hpp"
38 #include "memory/iterator.inline.hpp"
39 #include "memory/resourceArea.hpp"
40 #include "oops/compressedOops.inline.hpp"
41 #include "runtime/atomic.hpp"
42 #include "runtime/orderAccess.hpp"
43 #include "utilities/align.hpp"
44
45 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
46 #ifdef verify_oop
47 #undef verify_oop
48 #endif
49
50 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
51 private:
52 const char* _phase;
53 ShenandoahVerifier::VerifyOptions _options;
54 ShenandoahVerifierStack* _stack;
55 ShenandoahHeap* _heap;
56 MarkBitMap* _map;
57 ShenandoahLivenessData* _ld;
58 void* _interior_loc;
59 oop _loc;
60
61 public:
62 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
63 const char* phase, ShenandoahVerifier::VerifyOptions options) :
64 _phase(phase),
65 _options(options),
66 _stack(stack),
67 _heap(ShenandoahHeap::heap()),
68 _map(map),
69 _ld(ld),
70 _interior_loc(NULL),
71 _loc(NULL) { }
72
73 private:
74 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
75 if (!test) {
76 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
77 }
78 }
79
80 template <class T>
81 void do_oop_work(T* p) {
82 T o = RawAccess<>::oop_load(p);
83 if (!CompressedOops::is_null(o)) {
84 oop obj = CompressedOops::decode_not_null(o);
85
86 // Single threaded verification can use faster non-atomic stack and bitmap
87 // methods.
88 //
89 // For performance reasons, only fully verify non-marked field values.
90 // We are here when the host object for *p is already marked.
91
92 if (_map->par_mark(obj)) {
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->index();
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->index()], (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 };
402
403 class ShenandoahVerifierReachableTask : public AbstractGangTask {
404 private:
405 const char* _label;
406 ShenandoahRootVerifier* _verifier;
407 ShenandoahVerifier::VerifyOptions _options;
408 ShenandoahHeap* _heap;
409 ShenandoahLivenessData* _ld;
410 MarkBitMap* _bitmap;
411 volatile size_t _processed;
412
413 public:
414 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
415 ShenandoahLivenessData* ld,
416 ShenandoahRootVerifier* verifier,
417 const char* label,
418 ShenandoahVerifier::VerifyOptions options) :
419 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
420 _label(label),
421 _verifier(verifier),
422 _options(options),
423 _heap(ShenandoahHeap::heap()),
424 _ld(ld),
425 _bitmap(bitmap),
426 _processed(0) {};
427
428 size_t processed() {
429 return _processed;
430 }
431
432 virtual void work(uint worker_id) {
433 ResourceMark rm;
434 ShenandoahVerifierStack stack;
435
436 // On level 2, we need to only check the roots once.
437 // On level 3, we want to check the roots, and seed the local stack.
438 // It is a lesser evil to accept multiple root scans at level 3, because
439 // extended parallelism would buy us out.
440 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
441 || (ShenandoahVerifyLevel >= 3)) {
442 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
443 ShenandoahMessageBuffer("%s, Roots", _label),
444 _options);
445 if (_heap->unload_classes()) {
446 _verifier->strong_roots_do(&cl);
447 } else {
448 _verifier->roots_do(&cl);
449 }
450 }
451
452 size_t processed = 0;
453
454 if (ShenandoahVerifyLevel >= 3) {
455 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
456 ShenandoahMessageBuffer("%s, Reachable", _label),
457 _options);
458 while (!stack.is_empty()) {
459 processed++;
460 ShenandoahVerifierTask task = stack.pop();
461 cl.verify_oops_from(task.obj());
462 }
463 }
464
465 Atomic::add(&_processed, processed);
466 }
467 };
468
469 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
470 private:
471 const char* _label;
472 ShenandoahVerifier::VerifyOptions _options;
473 ShenandoahHeap *_heap;
474 MarkBitMap* _bitmap;
475 ShenandoahLivenessData* _ld;
476 volatile size_t _claimed;
477 volatile size_t _processed;
478
479 public:
480 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
481 ShenandoahLivenessData* ld,
482 const char* label,
483 ShenandoahVerifier::VerifyOptions options) :
484 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
485 _label(label),
486 _options(options),
487 _heap(ShenandoahHeap::heap()),
488 _bitmap(bitmap),
489 _ld(ld),
490 _claimed(0),
491 _processed(0) {};
492
493 size_t processed() {
494 return _processed;
495 }
496
497 virtual void work(uint worker_id) {
498 ShenandoahVerifierStack stack;
499 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
500 ShenandoahMessageBuffer("%s, Marked", _label),
501 _options);
502
503 while (true) {
504 size_t v = Atomic::fetch_and_add(&_claimed, 1u);
505 if (v < _heap->num_regions()) {
506 ShenandoahHeapRegion* r = _heap->get_region(v);
507 if (!r->is_humongous() && !r->is_trash()) {
508 work_regular(r, stack, cl);
509 } else if (r->is_humongous_start()) {
510 work_humongous(r, stack, cl);
511 }
512 } else {
513 break;
514 }
515 }
516 }
517
518 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
519 size_t processed = 0;
520 HeapWord* obj = r->bottom();
521 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
522 verify_and_follow(obj, stack, cl, &processed);
523 }
524 Atomic::add(&_processed, processed);
525 }
526
527 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
528 size_t processed = 0;
529 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
530 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
531
532 // Bitmaps, before TAMS
533 if (tams > r->bottom()) {
534 HeapWord* start = r->bottom();
535 HeapWord* addr = mark_bit_map->get_next_marked_addr(start, tams);
536
537 while (addr < tams) {
538 verify_and_follow(addr, stack, cl, &processed);
539 addr += 1;
540 if (addr < tams) {
541 addr = mark_bit_map->get_next_marked_addr(addr, tams);
542 }
543 }
544 }
545
546 // Size-based, after TAMS
547 {
548 HeapWord* limit = r->top();
549 HeapWord* addr = tams;
550
551 while (addr < limit) {
552 verify_and_follow(addr, stack, cl, &processed);
553 addr += oop(addr)->size();
554 }
555 }
556
557 Atomic::add(&_processed, processed);
558 }
559
560 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
561 if (!_bitmap->par_mark(addr)) return;
562
563 // Verify the object itself:
564 oop obj = oop(addr);
565 cl.verify_oop_standalone(obj);
566
567 // Verify everything reachable from that object too, hopefully realizing
568 // everything was already marked, and never touching further:
569 cl.verify_oops_from(obj);
570 (*processed)++;
571
572 while (!stack.is_empty()) {
573 ShenandoahVerifierTask task = stack.pop();
574 cl.verify_oops_from(task.obj());
575 (*processed)++;
576 }
577 }
578 };
579
580 class VerifyThreadGCState : public ThreadClosure {
581 private:
582 const char* _label;
583 char _expected;
584
585 public:
586 VerifyThreadGCState(const char* label, char expected) : _expected(expected) {}
587 void do_thread(Thread* t) {
588 char actual = ShenandoahThreadLocalData::gc_state(t);
589 if (actual != _expected) {
590 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
591 }
592 }
593 };
594
595 class ShenandoahGCStateResetter : public StackObj {
596 private:
597 ShenandoahHeap* const _heap;
598 char _gc_state;
599
600 public:
601 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
602 _gc_state = _heap->gc_state();
603 _heap->_gc_state.clear();
604 }
605
606 ~ShenandoahGCStateResetter() {
607 _heap->_gc_state.set(_gc_state);
608 assert(_heap->gc_state() == _gc_state, "Should be restored");
609 }
610 };
611
612 void ShenandoahVerifier::verify_at_safepoint(const char *label,
613 VerifyForwarded forwarded, VerifyMarked marked,
614 VerifyCollectionSet cset,
615 VerifyLiveness liveness, VerifyRegions regions,
616 VerifyGCState gcstate,
617 VerifyWeakRoots weak_roots) {
618 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
619 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
620
621 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
622 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
623
624 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
625
626 // GC state checks
627 {
628 char expected = -1;
629 bool enabled;
630 switch (gcstate) {
631 case _verify_gcstate_disable:
632 enabled = false;
633 break;
634 case _verify_gcstate_forwarded:
635 enabled = true;
636 expected = ShenandoahHeap::HAS_FORWARDED;
637 break;
638 case _verify_gcstate_evacuation:
639 enabled = true;
640 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
641 break;
642 case _verify_gcstate_stable:
643 enabled = true;
644 expected = ShenandoahHeap::STABLE;
645 break;
646 default:
647 enabled = false;
648 assert(false, "Unhandled gc-state verification");
649 }
650
651 if (enabled) {
652 char actual = _heap->gc_state();
653 if (actual != expected) {
654 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
655 }
656
657 VerifyThreadGCState vtgcs(label, expected);
658 Threads::java_threads_do(&vtgcs);
659 }
660 }
661
662 // Deactivate barriers temporarily: Verifier wants plain heap accesses
663 ShenandoahGCStateResetter resetter;
664
665 // Heap size checks
666 {
667 ShenandoahHeapLocker lock(_heap->lock());
668
669 ShenandoahCalculateRegionStatsClosure cl;
670 _heap->heap_region_iterate(&cl);
671 size_t heap_used = _heap->used();
672 guarantee(cl.used() == heap_used,
673 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
674 label,
675 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
676 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
677
678 size_t heap_committed = _heap->committed();
679 guarantee(cl.committed() == heap_committed,
680 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
681 label,
682 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
683 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
684 }
685
686 // Internal heap region checks
687 if (ShenandoahVerifyLevel >= 1) {
688 ShenandoahVerifyHeapRegionClosure cl(label, regions);
689 _heap->heap_region_iterate(&cl);
690 }
691
692 OrderAccess::fence();
693
694 if (UseTLAB) {
695 _heap->labs_make_parsable();
696 }
697
698 // Allocate temporary bitmap for storing marking wavefront:
699 _verification_bit_map->clear();
700
701 // Allocate temporary array for storing liveness data
702 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
703 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
704
705 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
706
707 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
708 // This verifies what application can see, since it only cares about reachable objects.
709 size_t count_reachable = 0;
710 if (ShenandoahVerifyLevel >= 2) {
711 ShenandoahRootVerifier verifier;
712 switch (weak_roots) {
713 case _verify_serial_weak_roots:
714 verifier.excludes(ShenandoahRootVerifier::ConcurrentWeakRoots);
715 break;
716 case _verify_concurrent_weak_roots:
717 verifier.excludes(ShenandoahRootVerifier::SerialWeakRoots);
718 break;
719 case _verify_all_weak_roots:
720 break;
721 default:
722 ShouldNotReachHere();
723 }
724
725 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
726 _heap->workers()->run_task(&task);
727 count_reachable = task.processed();
728 }
729
730 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
731 // not the application, can see during the region scans. There is no reason to process the objects
732 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
733 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
734 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
735 // version
736
737 size_t count_marked = 0;
738 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
739 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
740 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
741 _heap->workers()->run_task(&task);
742 count_marked = task.processed();
743 } else {
744 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
745 }
746
747 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
748 // marked objects.
749
750 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
751 for (size_t i = 0; i < _heap->num_regions(); i++) {
752 ShenandoahHeapRegion* r = _heap->get_region(i);
753
754 juint verf_live = 0;
755 if (r->is_humongous()) {
756 // For humongous objects, test if start region is marked live, and if so,
757 // all humongous regions in that chain have live data equal to their "used".
758 juint start_live = Atomic::load_acquire(&ld[r->humongous_start_region()->index()]);
759 if (start_live > 0) {
760 verf_live = (juint)(r->used() / HeapWordSize);
761 }
762 } else {
763 verf_live = Atomic::load_acquire(&ld[r->index()]);
764 }
765
766 size_t reg_live = r->get_live_data_words();
767 if (reg_live != verf_live) {
768 ResourceMark rm;
769 stringStream ss;
770 r->print_on(&ss);
771 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
772 label, reg_live, verf_live, ss.as_string());
773 }
774 }
775 }
776
777 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
778 label, ShenandoahVerifyLevel, count_reachable, count_marked);
779
780 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
781 }
782
783 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
784 verify_at_safepoint(
785 "Generic Verification",
786 _verify_forwarded_allow, // conservatively allow forwarded
787 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
788 _verify_cset_disable, // cset may be inconsistent
789 _verify_liveness_disable, // no reliable liveness data
790 _verify_regions_disable, // no reliable region data
791 _verify_gcstate_disable, // no data about gcstate
792 _verify_all_weak_roots
793 );
794 }
795
796 void ShenandoahVerifier::verify_before_concmark() {
797 verify_at_safepoint(
798 "Before Mark",
799 _verify_forwarded_none, // UR should have fixed up
800 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
801 _verify_cset_none, // UR should have fixed this
802 _verify_liveness_disable, // no reliable liveness data
803 _verify_regions_notrash, // no trash regions
804 _verify_gcstate_stable, // there are no forwarded objects
805 _verify_all_weak_roots
806 );
807 }
808
809 void ShenandoahVerifier::verify_after_concmark() {
810 verify_at_safepoint(
811 "After Mark",
812 _verify_forwarded_none, // no forwarded references
813 _verify_marked_complete, // bitmaps as precise as we can get
814 _verify_cset_none, // no references to cset anymore
815 _verify_liveness_complete, // liveness data must be complete here
816 _verify_regions_disable, // trash regions not yet recycled
817 _verify_gcstate_stable, // mark should have stabilized the heap
818 _verify_all_weak_roots
819 );
820 }
821
822 void ShenandoahVerifier::verify_before_evacuation() {
823 // Concurrent weak roots are evacuated during concurrent phase
824 VerifyWeakRoots verify_weak_roots = ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() ?
825 _verify_serial_weak_roots :
826 _verify_all_weak_roots;
827
828 verify_at_safepoint(
829 "Before Evacuation",
830 _verify_forwarded_none, // no forwarded references
831 _verify_marked_complete, // walk over marked objects too
832 _verify_cset_disable, // non-forwarded references to cset expected
833 _verify_liveness_complete, // liveness data must be complete here
834 _verify_regions_disable, // trash regions not yet recycled
835 _verify_gcstate_stable, // mark should have stabilized the heap
836 verify_weak_roots
837 );
838 }
839
840 void ShenandoahVerifier::verify_during_evacuation() {
841 // Concurrent weak roots are evacuated during concurrent phase
842 VerifyWeakRoots verify_weak_roots = ShenandoahConcurrentRoots::should_do_concurrent_class_unloading() ?
843 _verify_serial_weak_roots :
844 _verify_all_weak_roots;
845
846 verify_at_safepoint(
847 "During Evacuation",
848 _verify_forwarded_allow, // some forwarded references are allowed
849 _verify_marked_disable, // walk only roots
850 _verify_cset_disable, // some cset references are not forwarded yet
851 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
852 _verify_regions_disable, // trash regions not yet recycled
853 _verify_gcstate_evacuation, // evacuation is in progress
854 verify_weak_roots
855 );
856 }
857
858 void ShenandoahVerifier::verify_after_evacuation() {
859 verify_at_safepoint(
860 "After Evacuation",
861 _verify_forwarded_allow, // objects are still forwarded
862 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
863 _verify_cset_forwarded, // all cset refs are fully forwarded
864 _verify_liveness_disable, // no reliable liveness data anymore
865 _verify_regions_notrash, // trash regions have been recycled already
866 _verify_gcstate_forwarded, // evacuation produced some forwarded objects
867 _verify_all_weak_roots
868 );
869 }
870
871 void ShenandoahVerifier::verify_before_updaterefs() {
872 verify_at_safepoint(
873 "Before Updating References",
874 _verify_forwarded_allow, // forwarded references allowed
875 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
876 _verify_cset_forwarded, // all cset refs are fully forwarded
877 _verify_liveness_disable, // no reliable liveness data anymore
878 _verify_regions_notrash, // trash regions have been recycled already
879 _verify_gcstate_forwarded, // evacuation should have produced some forwarded objects
880 _verify_all_weak_roots
881 );
882 }
883
884 void ShenandoahVerifier::verify_after_updaterefs() {
885 verify_at_safepoint(
886 "After Updating References",
887 _verify_forwarded_none, // no forwarded references
888 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
889 _verify_cset_none, // no cset references, all updated
890 _verify_liveness_disable, // no reliable liveness data anymore
891 _verify_regions_nocset, // no cset regions, trash regions have appeared
892 _verify_gcstate_stable, // update refs had cleaned up forwarded objects
893 _verify_all_weak_roots
894 );
895 }
896
897 void ShenandoahVerifier::verify_after_degenerated() {
898 verify_at_safepoint(
899 "After Degenerated GC",
900 _verify_forwarded_none, // all objects are non-forwarded
901 _verify_marked_complete, // all objects are marked in complete bitmap
902 _verify_cset_none, // no cset references
903 _verify_liveness_disable, // no reliable liveness data anymore
904 _verify_regions_notrash_nocset, // no trash, no cset
905 _verify_gcstate_stable, // degenerated refs had cleaned up forwarded objects
906 _verify_all_weak_roots
907 );
908 }
909
910 void ShenandoahVerifier::verify_before_fullgc() {
911 verify_at_safepoint(
912 "Before Full GC",
913 _verify_forwarded_allow, // can have forwarded objects
914 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
915 _verify_cset_disable, // cset might be foobared
916 _verify_liveness_disable, // no reliable liveness data anymore
917 _verify_regions_disable, // no reliable region data here
918 _verify_gcstate_disable, // no reliable gcstate data
919 _verify_all_weak_roots
920 );
921 }
922
923 void ShenandoahVerifier::verify_after_fullgc() {
924 verify_at_safepoint(
925 "After Full GC",
926 _verify_forwarded_none, // all objects are non-forwarded
927 _verify_marked_complete, // all objects are marked in complete bitmap
928 _verify_cset_none, // no cset references
929 _verify_liveness_disable, // no reliable liveness data anymore
930 _verify_regions_notrash_nocset, // no trash, no cset
931 _verify_gcstate_stable, // full gc cleaned up everything
932 _verify_all_weak_roots
933 );
934 }
935
936 class ShenandoahVerifyNoForwared : public OopClosure {
937 private:
938 template <class T>
939 void do_oop_work(T* p) {
940 T o = RawAccess<>::oop_load(p);
941 if (!CompressedOops::is_null(o)) {
942 oop obj = CompressedOops::decode_not_null(o);
943 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
944 if (obj != fwd) {
945 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
946 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
947 }
948 }
949 }
950
951 public:
952 void do_oop(narrowOop* p) { do_oop_work(p); }
953 void do_oop(oop* p) { do_oop_work(p); }
954 };
955
956 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
957 private:
958 template <class T>
959 void do_oop_work(T* p) {
960 T o = RawAccess<>::oop_load(p);
961 if (!CompressedOops::is_null(o)) {
962 oop obj = CompressedOops::decode_not_null(o);
963 ShenandoahHeap* heap = ShenandoahHeap::heap();
964
965 if (!heap->marking_context()->is_marked(obj)) {
966 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
967 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
968 }
969
970 if (heap->in_collection_set(obj)) {
971 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
972 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
973 }
974
975 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
976 if (obj != fwd) {
977 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
978 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
979 }
980 }
981 }
982
983 public:
984 void do_oop(narrowOop* p) { do_oop_work(p); }
985 void do_oop(oop* p) { do_oop_work(p); }
986 };
987
988 void ShenandoahVerifier::verify_roots_in_to_space() {
989 ShenandoahRootVerifier verifier;
990 ShenandoahVerifyInToSpaceClosure cl;
991 verifier.oops_do(&cl);
992 }
993
994 void ShenandoahVerifier::verify_roots_in_to_space_except(ShenandoahRootVerifier::RootTypes types) {
995 ShenandoahRootVerifier verifier;
996 verifier.excludes(types);
997 ShenandoahVerifyInToSpaceClosure cl;
998 verifier.oops_do(&cl);
999 }
1000
1001 void ShenandoahVerifier::verify_roots_no_forwarded() {
1002 ShenandoahRootVerifier verifier;
1003 ShenandoahVerifyNoForwared cl;
1004 verifier.oops_do(&cl);
1005 }
1006
1007 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
1008 ShenandoahRootVerifier verifier;
1009 verifier.excludes(types);
1010 ShenandoahVerifyNoForwared cl;
1011 verifier.oops_do(&cl);
1012 }