1 /*
2 * Copyright (c) 2017, 2021, 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 #include "gc/shared/tlab_globals.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeapRegion.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 "runtime/threads.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 static bool is_instance_ref_klass(Klass* k) {
51 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
52 }
53
54 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
55 public:
56 virtual bool discover_reference(oop obj, ReferenceType type) {
57 return true;
58 }
59 };
60
61 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
62 private:
63 const char* _phase;
64 ShenandoahVerifier::VerifyOptions _options;
65 ShenandoahVerifierStack* _stack;
66 ShenandoahHeap* _heap;
67 MarkBitMap* _map;
68 ShenandoahLivenessData* _ld;
69 void* _interior_loc;
70 oop _loc;
71
72 public:
73 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
74 const char* phase, ShenandoahVerifier::VerifyOptions options) :
75 _phase(phase),
76 _options(options),
77 _stack(stack),
78 _heap(ShenandoahHeap::heap()),
79 _map(map),
80 _ld(ld),
81 _interior_loc(nullptr),
82 _loc(nullptr) {
83 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
84 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
85 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
86 }
87 }
88
89 private:
90 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
91 if (!test) {
92 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
93 }
94 }
95
96 template <class T>
97 void do_oop_work(T* p) {
98 T o = RawAccess<>::oop_load(p);
99 if (!CompressedOops::is_null(o)) {
100 oop obj = CompressedOops::decode_not_null(o);
101 if (is_instance_ref_klass(obj->klass())) {
102 obj = ShenandoahForwarding::get_forwardee(obj);
103 }
104 // Single threaded verification can use faster non-atomic stack and bitmap
105 // methods.
106 //
107 // For performance reasons, only fully verify non-marked field values.
108 // We are here when the host object for *p is already marked.
109
110 if (_map->par_mark(obj)) {
111 verify_oop_at(p, obj);
112 _stack->push(ShenandoahVerifierTask(obj));
113 }
114 }
115 }
116
117 void verify_oop(oop obj) {
118 // Perform consistency checks with gradually decreasing safety level. This guarantees
119 // that failure report would not try to touch something that was not yet verified to be
120 // safe to process.
121
122 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
123 "oop must be in heap");
124 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
125 "oop must be aligned");
126
127 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
128 Klass* obj_klass = obj->klass_or_null();
129
130 // Verify that obj is not in dead space:
131 {
132 // Do this before touching obj->size()
133 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
134 "Object klass pointer should not be null");
135 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
136 "Object klass pointer must go to metaspace");
147 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
148 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
149 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
150 "Humongous object is in continuation that fits it");
151 }
152 }
153
154 // ------------ obj is safe at this point --------------
155
156 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
157 "Object should be in active region");
158
159 switch (_options._verify_liveness) {
160 case ShenandoahVerifier::_verify_liveness_disable:
161 // skip
162 break;
163 case ShenandoahVerifier::_verify_liveness_complete:
164 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
165 // fallthrough for fast failure for un-live regions:
166 case ShenandoahVerifier::_verify_liveness_conservative:
167 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
168 "Object must belong to region with live data");
169 break;
170 default:
171 assert(false, "Unhandled liveness verification");
172 }
173 }
174
175 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
176
177 ShenandoahHeapRegion* fwd_reg = nullptr;
178
179 if (obj != fwd) {
180 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
181 "Forwardee must be in heap");
182 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
183 "Forwardee is set");
184 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
185 "Forwardee must be aligned");
186
187 // Do this before touching fwd->size()
196 fwd_reg = _heap->heap_region_containing(fwd);
197
198 // Verify that forwardee is not in the dead space:
199 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
200 "Should have no humongous forwardees");
201
202 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
203 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
204 "Forwardee start should be within the region");
205 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
206 "Forwardee end should be within the region");
207
208 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
209 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
210 "Double forwarding");
211 } else {
212 fwd_reg = obj_reg;
213 }
214
215 // ------------ obj and fwd are safe at this point --------------
216
217 switch (_options._verify_marked) {
218 case ShenandoahVerifier::_verify_marked_disable:
219 // skip
220 break;
221 case ShenandoahVerifier::_verify_marked_incomplete:
222 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
223 "Must be marked in incomplete bitmap");
224 break;
225 case ShenandoahVerifier::_verify_marked_complete:
226 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
227 "Must be marked in complete bitmap");
228 break;
229 case ShenandoahVerifier::_verify_marked_complete_except_references:
230 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
231 "Must be marked in complete bitmap, except j.l.r.Reference referents");
232 break;
233 default:
234 assert(false, "Unhandled mark verification");
235 }
236
237 switch (_options._verify_forwarded) {
238 case ShenandoahVerifier::_verify_forwarded_disable:
239 // skip
240 break;
241 case ShenandoahVerifier::_verify_forwarded_none: {
242 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
243 "Should not be forwarded");
244 break;
245 }
246 case ShenandoahVerifier::_verify_forwarded_allow: {
247 if (obj != fwd) {
248 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
249 "Forwardee should be in another region");
250 }
296 void verify_oop_standalone(oop obj) {
297 _interior_loc = nullptr;
298 verify_oop(obj);
299 _interior_loc = nullptr;
300 }
301
302 /**
303 * Verify oop fields from this object.
304 * @param obj host object for verified fields
305 */
306 void verify_oops_from(oop obj) {
307 _loc = obj;
308 obj->oop_iterate(this);
309 _loc = nullptr;
310 }
311
312 virtual void do_oop(oop* p) { do_oop_work(p); }
313 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
314 };
315
316 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
317 private:
318 size_t _used, _committed, _garbage;
319 public:
320 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
321
322 void heap_region_do(ShenandoahHeapRegion* r) {
323 _used += r->used();
324 _garbage += r->garbage();
325 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
326 }
327
328 size_t used() { return _used; }
329 size_t committed() { return _committed; }
330 size_t garbage() { return _garbage; }
331 };
332
333 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
334 private:
335 ShenandoahHeap* _heap;
336 const char* _phase;
337 ShenandoahVerifier::VerifyRegions _regions;
338 public:
339 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
340 _heap(ShenandoahHeap::heap()),
341 _phase(phase),
342 _regions(regions) {};
343
344 void print_failure(ShenandoahHeapRegion* r, const char* label) {
345 ResourceMark rm;
346
347 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
348
349 stringStream ss;
350 r->print_on(&ss);
394 "Complete TAMS should not be larger than top");
395
396 verify(r, r->get_live_data_bytes() <= r->capacity(),
397 "Live data cannot be larger than capacity");
398
399 verify(r, r->garbage() <= r->capacity(),
400 "Garbage cannot be larger than capacity");
401
402 verify(r, r->used() <= r->capacity(),
403 "Used cannot be larger than capacity");
404
405 verify(r, r->get_shared_allocs() <= r->capacity(),
406 "Shared alloc count should not be larger than capacity");
407
408 verify(r, r->get_tlab_allocs() <= r->capacity(),
409 "TLAB alloc count should not be larger than capacity");
410
411 verify(r, r->get_gclab_allocs() <= r->capacity(),
412 "GCLAB alloc count should not be larger than capacity");
413
414 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
415 "Accurate accounting: shared + TLAB + GCLAB = used");
416
417 verify(r, !r->is_empty() || !r->has_live(),
418 "Empty regions should not have live data");
419
420 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
421 "Transitional: region flags and collection set agree");
422 }
423 };
424
425 class ShenandoahVerifierReachableTask : public WorkerTask {
426 private:
427 const char* _label;
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,
477 while (!stack.is_empty()) {
478 processed++;
479 ShenandoahVerifierTask task = stack.pop();
480 cl.verify_oops_from(task.obj());
481 }
482 }
483
484 Atomic::add(&_processed, processed, memory_order_relaxed);
485 }
486 };
487
488 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
489 private:
490 const char* _label;
491 ShenandoahVerifier::VerifyOptions _options;
492 ShenandoahHeap *_heap;
493 MarkBitMap* _bitmap;
494 ShenandoahLivenessData* _ld;
495 volatile size_t _claimed;
496 volatile size_t _processed;
497
498 public:
499 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
500 ShenandoahLivenessData* ld,
501 const char* label,
502 ShenandoahVerifier::VerifyOptions options) :
503 WorkerTask("Shenandoah Verifier Marked Objects"),
504 _label(label),
505 _options(options),
506 _heap(ShenandoahHeap::heap()),
507 _bitmap(bitmap),
508 _ld(ld),
509 _claimed(0),
510 _processed(0) {};
511
512 size_t processed() {
513 return Atomic::load(&_processed);
514 }
515
516 virtual void work(uint worker_id) {
517 ShenandoahVerifierStack stack;
518 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
519 ShenandoahMessageBuffer("%s, Marked", _label),
520 _options);
521
522 while (true) {
523 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
524 if (v < _heap->num_regions()) {
525 ShenandoahHeapRegion* r = _heap->get_region(v);
526 if (!r->is_humongous() && !r->is_trash()) {
527 work_regular(r, stack, cl);
528 } else if (r->is_humongous_start()) {
529 work_humongous(r, stack, cl);
530 }
531 } else {
532 break;
533 }
534 }
535 }
536
537 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
538 size_t processed = 0;
539 HeapWord* obj = r->bottom();
540 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
541 verify_and_follow(obj, stack, cl, &processed);
542 }
543 Atomic::add(&_processed, processed, memory_order_relaxed);
544 }
545
546 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
547 size_t processed = 0;
548 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
549 HeapWord* tams = ctx->top_at_mark_start(r);
550
551 // Bitmaps, before TAMS
552 if (tams > r->bottom()) {
553 HeapWord* start = r->bottom();
554 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
555
556 while (addr < tams) {
589 cl.verify_oops_from(obj);
590 (*processed)++;
591 }
592 while (!stack.is_empty()) {
593 ShenandoahVerifierTask task = stack.pop();
594 cl.verify_oops_from(task.obj());
595 (*processed)++;
596 }
597 }
598 };
599
600 class VerifyThreadGCState : public ThreadClosure {
601 private:
602 const char* const _label;
603 char const _expected;
604
605 public:
606 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
607 void do_thread(Thread* t) {
608 char actual = ShenandoahThreadLocalData::gc_state(t);
609 if (actual != _expected) {
610 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
611 }
612 }
613 };
614
615 void ShenandoahVerifier::verify_at_safepoint(const char *label,
616 VerifyForwarded forwarded, VerifyMarked marked,
617 VerifyCollectionSet cset,
618 VerifyLiveness liveness, VerifyRegions regions,
619 VerifyGCState gcstate) {
620 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
621 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
622
623 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
624 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
625
626 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
627
628 // GC state checks
629 {
630 char expected = -1;
631 bool enabled;
632 switch (gcstate) {
633 case _verify_gcstate_disable:
634 enabled = false;
635 break;
636 case _verify_gcstate_forwarded:
637 enabled = true;
638 expected = ShenandoahHeap::HAS_FORWARDED;
639 break;
640 case _verify_gcstate_evacuation:
641 enabled = true;
642 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
643 if (!_heap->is_stw_gc_in_progress()) {
644 // Only concurrent GC sets this.
645 expected |= ShenandoahHeap::WEAK_ROOTS;
646 }
647 break;
648 case _verify_gcstate_stable:
649 enabled = true;
650 expected = ShenandoahHeap::STABLE;
651 break;
652 case _verify_gcstate_stable_weakroots:
653 enabled = true;
654 expected = ShenandoahHeap::STABLE;
655 if (!_heap->is_stw_gc_in_progress()) {
656 // Only concurrent GC sets this.
657 expected |= ShenandoahHeap::WEAK_ROOTS;
658 }
659 break;
660 default:
661 enabled = false;
662 assert(false, "Unhandled gc-state verification");
663 }
664
665 if (enabled) {
666 char actual = _heap->gc_state();
667 if (actual != expected) {
668 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
669 }
670
671 VerifyThreadGCState vtgcs(label, expected);
672 Threads::java_threads_do(&vtgcs);
673 }
674 }
675
676 // Deactivate barriers temporarily: Verifier wants plain heap accesses
677 ShenandoahGCStateResetter resetter;
678
679 // Heap size checks
680 {
681 ShenandoahHeapLocker lock(_heap->lock());
682
683 ShenandoahCalculateRegionStatsClosure cl;
684 _heap->heap_region_iterate(&cl);
685 size_t heap_used = _heap->used();
686 guarantee(cl.used() == heap_used,
687 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
688 label,
689 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
690 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
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 "%s, regions-committed = " SIZE_FORMAT "%s",
695 label,
696 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
697 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
698 }
699
700 // Internal heap region checks
701 if (ShenandoahVerifyLevel >= 1) {
702 ShenandoahVerifyHeapRegionClosure cl(label, regions);
703 _heap->heap_region_iterate(&cl);
704 }
705
706 OrderAccess::fence();
707
708 if (UseTLAB) {
709 _heap->labs_make_parsable();
710 }
711
712 // Allocate temporary bitmap for storing marking wavefront:
713 _verification_bit_map->clear();
714
715 // Allocate temporary array for storing liveness data
716 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
717 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
718
719 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
720
721 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
722 // This verifies what application can see, since it only cares about reachable objects.
723 size_t count_reachable = 0;
724 if (ShenandoahVerifyLevel >= 2) {
725 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, 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 || marked == _verify_marked_complete_except_references)) {
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(&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(&ld[r->index()]);
764 }
765
766 size_t reg_live = r->get_live_data_words();
767 if (reg_live != verf_live) {
768 stringStream ss;
769 r->print_on(&ss);
770 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
771 label, reg_live, verf_live, ss.freeze());
772 }
773 }
774 }
775
776 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
777 label, ShenandoahVerifyLevel, count_reachable, count_marked);
778
779 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
780 }
781
782 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
783 verify_at_safepoint(
784 "Generic Verification",
785 _verify_forwarded_allow, // conservatively allow forwarded
786 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
787 _verify_cset_disable, // cset may be inconsistent
788 _verify_liveness_disable, // no reliable liveness data
789 _verify_regions_disable, // no reliable region data
790 _verify_gcstate_disable // no data about gcstate
791 );
792 }
793
794 void ShenandoahVerifier::verify_before_concmark() {
795 verify_at_safepoint(
796 "Before Mark",
797 _verify_forwarded_none, // UR should have fixed up
798 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
799 _verify_cset_none, // UR should have fixed this
800 _verify_liveness_disable, // no reliable liveness data
801 _verify_regions_notrash, // no trash regions
802 _verify_gcstate_stable // there are no forwarded objects
803 );
804 }
805
806 void ShenandoahVerifier::verify_after_concmark() {
807 verify_at_safepoint(
808 "After Mark",
809 _verify_forwarded_none, // no forwarded references
810 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
811 _verify_cset_none, // no references to cset anymore
812 _verify_liveness_complete, // liveness data must be complete here
813 _verify_regions_disable, // trash regions not yet recycled
814 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
815 );
816 }
817
818 void ShenandoahVerifier::verify_before_evacuation() {
819 verify_at_safepoint(
820 "Before Evacuation",
821 _verify_forwarded_none, // no forwarded references
822 _verify_marked_complete_except_references, // walk over marked objects too
823 _verify_cset_disable, // non-forwarded references to cset expected
824 _verify_liveness_complete, // liveness data must be complete here
825 _verify_regions_disable, // trash regions not yet recycled
826 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
827 );
828 }
829
830 void ShenandoahVerifier::verify_during_evacuation() {
831 verify_at_safepoint(
832 "During Evacuation",
833 _verify_forwarded_allow, // some forwarded references are allowed
834 _verify_marked_disable, // walk only roots
835 _verify_cset_disable, // some cset references are not forwarded yet
836 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
837 _verify_regions_disable, // trash regions not yet recycled
838 _verify_gcstate_evacuation // evacuation is in progress
839 );
840 }
841
842 void ShenandoahVerifier::verify_after_evacuation() {
843 verify_at_safepoint(
844 "After Evacuation",
845 _verify_forwarded_allow, // objects are still forwarded
846 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
847 _verify_cset_forwarded, // all cset refs are fully forwarded
848 _verify_liveness_disable, // no reliable liveness data anymore
849 _verify_regions_notrash, // trash regions have been recycled already
850 _verify_gcstate_forwarded // evacuation produced some forwarded objects
851 );
852 }
853
854 void ShenandoahVerifier::verify_before_updaterefs() {
855 verify_at_safepoint(
856 "Before Updating References",
857 _verify_forwarded_allow, // forwarded references allowed
858 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
859 _verify_cset_forwarded, // all cset refs are fully forwarded
860 _verify_liveness_disable, // no reliable liveness data anymore
861 _verify_regions_notrash, // trash regions have been recycled already
862 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
863 );
864 }
865
866 void ShenandoahVerifier::verify_after_updaterefs() {
867 verify_at_safepoint(
868 "After Updating References",
869 _verify_forwarded_none, // no forwarded references
870 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
871 _verify_cset_none, // no cset references, all updated
872 _verify_liveness_disable, // no reliable liveness data anymore
873 _verify_regions_nocset, // no cset regions, trash regions have appeared
874 _verify_gcstate_stable // update refs had cleaned up forwarded objects
875 );
876 }
877
878 void ShenandoahVerifier::verify_after_degenerated() {
879 verify_at_safepoint(
880 "After Degenerated GC",
881 _verify_forwarded_none, // all objects are non-forwarded
882 _verify_marked_complete, // all objects are marked in complete bitmap
883 _verify_cset_none, // no cset references
884 _verify_liveness_disable, // no reliable liveness data anymore
885 _verify_regions_notrash_nocset, // no trash, no cset
886 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
887 );
888 }
889
890 void ShenandoahVerifier::verify_before_fullgc() {
891 verify_at_safepoint(
892 "Before Full GC",
893 _verify_forwarded_allow, // can have forwarded objects
894 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
895 _verify_cset_disable, // cset might be foobared
896 _verify_liveness_disable, // no reliable liveness data anymore
897 _verify_regions_disable, // no reliable region data here
898 _verify_gcstate_disable // no reliable gcstate data
899 );
900 }
901
902 void ShenandoahVerifier::verify_after_fullgc() {
903 verify_at_safepoint(
904 "After Full GC",
905 _verify_forwarded_none, // all objects are non-forwarded
906 _verify_marked_complete, // all objects are marked in complete bitmap
907 _verify_cset_none, // no cset references
908 _verify_liveness_disable, // no reliable liveness data anymore
909 _verify_regions_notrash_nocset, // no trash, no cset
910 _verify_gcstate_stable // full gc cleaned up everything
911 );
912 }
913
914 class ShenandoahVerifyNoForwared : public OopClosure {
915 private:
916 template <class T>
917 void do_oop_work(T* p) {
918 T o = RawAccess<>::oop_load(p);
919 if (!CompressedOops::is_null(o)) {
920 oop obj = CompressedOops::decode_not_null(o);
921 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
922 if (obj != fwd) {
923 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
924 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
925 }
926 }
927 }
928
929 public:
930 void do_oop(narrowOop* p) { do_oop_work(p); }
931 void do_oop(oop* p) { do_oop_work(p); }
932 };
933
934 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
935 private:
936 template <class T>
937 void do_oop_work(T* p) {
938 T o = RawAccess<>::oop_load(p);
939 if (!CompressedOops::is_null(o)) {
940 oop obj = CompressedOops::decode_not_null(o);
941 ShenandoahHeap* heap = ShenandoahHeap::heap();
942
943 if (!heap->marking_context()->is_marked(obj)) {
944 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
945 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
946 }
947
948 if (heap->in_collection_set(obj)) {
949 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
950 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
951 }
952
953 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
954 if (obj != fwd) {
955 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
956 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
957 }
958 }
959 }
960
961 public:
962 void do_oop(narrowOop* p) { do_oop_work(p); }
963 void do_oop(oop* p) { do_oop_work(p); }
964 };
965
966 void ShenandoahVerifier::verify_roots_in_to_space() {
967 ShenandoahVerifyInToSpaceClosure cl;
968 ShenandoahRootVerifier::roots_do(&cl);
969 }
970
971 void ShenandoahVerifier::verify_roots_no_forwarded() {
972 ShenandoahVerifyNoForwared cl;
973 ShenandoahRootVerifier::roots_do(&cl);
974 }
|
1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/shared/tlab_globals.hpp"
28 #include "gc/shenandoah/shenandoahAsserts.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
30 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
31 #include "gc/shenandoah/shenandoahGeneration.hpp"
32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
34 #include "gc/shenandoah/shenandoahOldGeneration.hpp"
35 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
36 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
37 #include "gc/shenandoah/shenandoahUtils.hpp"
38 #include "gc/shenandoah/shenandoahVerifier.hpp"
39 #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
40 #include "memory/allocation.hpp"
41 #include "memory/iterator.inline.hpp"
42 #include "memory/resourceArea.hpp"
43 #include "oops/compressedOops.inline.hpp"
44 #include "runtime/atomic.hpp"
45 #include "runtime/orderAccess.hpp"
46 #include "runtime/threads.hpp"
47 #include "utilities/align.hpp"
48
49 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
50 #ifdef verify_oop
51 #undef verify_oop
52 #endif
53
54 static bool is_instance_ref_klass(Klass* k) {
55 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
56 }
57
58 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
59 public:
60 virtual bool discover_reference(oop obj, ReferenceType type) {
61 return true;
62 }
63 };
64
65 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
66 private:
67 const char* _phase;
68 ShenandoahVerifier::VerifyOptions _options;
69 ShenandoahVerifierStack* _stack;
70 ShenandoahHeap* _heap;
71 MarkBitMap* _map;
72 ShenandoahLivenessData* _ld;
73 void* _interior_loc;
74 oop _loc;
75 ShenandoahGeneration* _generation;
76
77 public:
78 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
79 const char* phase, ShenandoahVerifier::VerifyOptions options) :
80 _phase(phase),
81 _options(options),
82 _stack(stack),
83 _heap(ShenandoahHeap::heap()),
84 _map(map),
85 _ld(ld),
86 _interior_loc(nullptr),
87 _loc(nullptr),
88 _generation(nullptr) {
89 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
90 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
91 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
92 }
93
94 if (_heap->mode()->is_generational()) {
95 _generation = _heap->active_generation();
96 assert(_generation != nullptr, "Expected active generation in this mode");
97 }
98 }
99
100 private:
101 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
102 if (!test) {
103 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
104 }
105 }
106
107 template <class T>
108 void do_oop_work(T* p) {
109 T o = RawAccess<>::oop_load(p);
110 if (!CompressedOops::is_null(o)) {
111 oop obj = CompressedOops::decode_not_null(o);
112 if (is_instance_ref_klass(obj->klass())) {
113 obj = ShenandoahForwarding::get_forwardee(obj);
114 }
115 // Single threaded verification can use faster non-atomic stack and bitmap
116 // methods.
117 //
118 // For performance reasons, only fully verify non-marked field values.
119 // We are here when the host object for *p is already marked.
120
121 // TODO: We should consider specializing this closure by generation ==/!= null,
122 // to avoid in_generation check on fast path here for non-generational mode.
123 if (in_generation(obj) && _map->par_mark(obj)) {
124 verify_oop_at(p, obj);
125 _stack->push(ShenandoahVerifierTask(obj));
126 }
127 }
128 }
129
130 bool in_generation(oop obj) {
131 if (_generation == nullptr) {
132 return true;
133 }
134
135 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
136 return _generation->contains(region);
137 }
138
139 void verify_oop(oop obj) {
140 // Perform consistency checks with gradually decreasing safety level. This guarantees
141 // that failure report would not try to touch something that was not yet verified to be
142 // safe to process.
143
144 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
145 "oop must be in heap");
146 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
147 "oop must be aligned");
148
149 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
150 Klass* obj_klass = obj->klass_or_null();
151
152 // Verify that obj is not in dead space:
153 {
154 // Do this before touching obj->size()
155 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
156 "Object klass pointer should not be null");
157 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
158 "Object klass pointer must go to metaspace");
169 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
170 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
171 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
172 "Humongous object is in continuation that fits it");
173 }
174 }
175
176 // ------------ obj is safe at this point --------------
177
178 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
179 "Object should be in active region");
180
181 switch (_options._verify_liveness) {
182 case ShenandoahVerifier::_verify_liveness_disable:
183 // skip
184 break;
185 case ShenandoahVerifier::_verify_liveness_complete:
186 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
187 // fallthrough for fast failure for un-live regions:
188 case ShenandoahVerifier::_verify_liveness_conservative:
189 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
190 (obj_reg->is_old() && ShenandoahHeap::heap()->is_gc_generation_young()),
191 "Object must belong to region with live data");
192 break;
193 default:
194 assert(false, "Unhandled liveness verification");
195 }
196 }
197
198 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
199
200 ShenandoahHeapRegion* fwd_reg = nullptr;
201
202 if (obj != fwd) {
203 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
204 "Forwardee must be in heap");
205 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
206 "Forwardee is set");
207 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
208 "Forwardee must be aligned");
209
210 // Do this before touching fwd->size()
219 fwd_reg = _heap->heap_region_containing(fwd);
220
221 // Verify that forwardee is not in the dead space:
222 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
223 "Should have no humongous forwardees");
224
225 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
226 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
227 "Forwardee start should be within the region");
228 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
229 "Forwardee end should be within the region");
230
231 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
232 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
233 "Double forwarding");
234 } else {
235 fwd_reg = obj_reg;
236 }
237
238 // ------------ obj and fwd are safe at this point --------------
239 // We allow for marked or old here for two reasons:
240 // 1. If this is a young collect, old objects wouldn't be marked. We've
241 // recently change the verifier traversal to only follow young objects
242 // during a young collect so this _shouldn't_ be necessary.
243 // 2. At present, we do not clear dead objects from the remembered set.
244 // Everything in the remembered set is old (ipso facto), so allowing for
245 // 'marked_or_old' covers the case of stale objects in rset.
246 // TODO: Just use 'is_marked' here.
247 switch (_options._verify_marked) {
248 case ShenandoahVerifier::_verify_marked_disable:
249 // skip
250 break;
251 case ShenandoahVerifier::_verify_marked_incomplete:
252 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked_or_old(obj),
253 "Must be marked in incomplete bitmap");
254 break;
255 case ShenandoahVerifier::_verify_marked_complete:
256 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
257 "Must be marked in complete bitmap");
258 break;
259 case ShenandoahVerifier::_verify_marked_complete_except_references:
260 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
261 "Must be marked in complete bitmap, except j.l.r.Reference referents");
262 break;
263 default:
264 assert(false, "Unhandled mark verification");
265 }
266
267 switch (_options._verify_forwarded) {
268 case ShenandoahVerifier::_verify_forwarded_disable:
269 // skip
270 break;
271 case ShenandoahVerifier::_verify_forwarded_none: {
272 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
273 "Should not be forwarded");
274 break;
275 }
276 case ShenandoahVerifier::_verify_forwarded_allow: {
277 if (obj != fwd) {
278 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
279 "Forwardee should be in another region");
280 }
326 void verify_oop_standalone(oop obj) {
327 _interior_loc = nullptr;
328 verify_oop(obj);
329 _interior_loc = nullptr;
330 }
331
332 /**
333 * Verify oop fields from this object.
334 * @param obj host object for verified fields
335 */
336 void verify_oops_from(oop obj) {
337 _loc = obj;
338 obj->oop_iterate(this);
339 _loc = nullptr;
340 }
341
342 virtual void do_oop(oop* p) { do_oop_work(p); }
343 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
344 };
345
346 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
347 // a subset (e.g. the young generation or old generation) of the total heap.
348 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
349 private:
350 size_t _used, _committed, _garbage, _regions, _humongous_waste;
351 public:
352 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0) {};
353
354 void heap_region_do(ShenandoahHeapRegion* r) {
355 _used += r->used();
356 _garbage += r->garbage();
357 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
358 if (r->is_humongous()) {
359 _humongous_waste += r->free();
360 }
361 _regions++;
362 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
363 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
364 }
365
366 size_t used() { return _used; }
367 size_t committed() { return _committed; }
368 size_t garbage() { return _garbage; }
369 size_t regions() { return _regions; }
370 size_t waste() { return _humongous_waste; }
371
372 // span is the total memory affiliated with these stats (some of which is in use and other is available)
373 size_t span() { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
374 };
375
376 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
377 public:
378 ShenandoahCalculateRegionStatsClosure old;
379 ShenandoahCalculateRegionStatsClosure young;
380 ShenandoahCalculateRegionStatsClosure global;
381
382 void heap_region_do(ShenandoahHeapRegion* r) override {
383 switch (r->affiliation()) {
384 case FREE:
385 return;
386 case YOUNG_GENERATION:
387 young.heap_region_do(r);
388 global.heap_region_do(r);
389 break;
390 case OLD_GENERATION:
391 old.heap_region_do(r);
392 global.heap_region_do(r);
393 break;
394 default:
395 ShouldNotReachHere();
396 }
397 }
398
399 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
400 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
401 generation->name(),
402 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
403 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
404 }
405
406 static void validate_usage(const bool adjust_for_padding,
407 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
408 ShenandoahHeap* heap = ShenandoahHeap::heap();
409 size_t generation_used = generation->used();
410 size_t generation_used_regions = generation->used_regions();
411 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
412 size_t pad = ShenandoahHeap::heap()->get_pad_for_promote_in_place();
413 generation_used += pad;
414 }
415
416 guarantee(stats.used() == generation_used,
417 "%s: generation (%s) used size must be consistent: generation-used: " SIZE_FORMAT "%s, regions-used: " SIZE_FORMAT "%s",
418 label, generation->name(),
419 byte_size_in_proper_unit(generation_used), proper_unit_for_byte_size(generation_used),
420 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
421
422 guarantee(stats.regions() == generation_used_regions,
423 "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
424 label, generation->name(), generation->used_regions(), stats.regions());
425
426 size_t generation_capacity = generation->max_capacity();
427 size_t humongous_regions_promoted = 0;
428 guarantee(stats.span() <= generation_capacity,
429 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") must not exceed current capacity (" SIZE_FORMAT "%s)",
430 label, generation->name(), stats.regions(),
431 byte_size_in_proper_unit(generation_capacity), proper_unit_for_byte_size(generation_capacity));
432
433 size_t humongous_waste = generation->get_humongous_waste();
434 guarantee(stats.waste() == humongous_waste,
435 "%s: generation (%s) humongous waste must be consistent: generation: " SIZE_FORMAT "%s, regions: " SIZE_FORMAT "%s",
436 label, generation->name(),
437 byte_size_in_proper_unit(humongous_waste), proper_unit_for_byte_size(humongous_waste),
438 byte_size_in_proper_unit(stats.waste()), proper_unit_for_byte_size(stats.waste()));
439 }
440 };
441
442 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
443 private:
444 ShenandoahHeap* _heap;
445 const char* _phase;
446 ShenandoahVerifier::VerifyRegions _regions;
447 public:
448 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
449 _heap(ShenandoahHeap::heap()),
450 _phase(phase),
451 _regions(regions) {};
452
453 void print_failure(ShenandoahHeapRegion* r, const char* label) {
454 ResourceMark rm;
455
456 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
457
458 stringStream ss;
459 r->print_on(&ss);
503 "Complete TAMS should not be larger than top");
504
505 verify(r, r->get_live_data_bytes() <= r->capacity(),
506 "Live data cannot be larger than capacity");
507
508 verify(r, r->garbage() <= r->capacity(),
509 "Garbage cannot be larger than capacity");
510
511 verify(r, r->used() <= r->capacity(),
512 "Used cannot be larger than capacity");
513
514 verify(r, r->get_shared_allocs() <= r->capacity(),
515 "Shared alloc count should not be larger than capacity");
516
517 verify(r, r->get_tlab_allocs() <= r->capacity(),
518 "TLAB alloc count should not be larger than capacity");
519
520 verify(r, r->get_gclab_allocs() <= r->capacity(),
521 "GCLAB alloc count should not be larger than capacity");
522
523 verify(r, r->get_plab_allocs() <= r->capacity(),
524 "PLAB alloc count should not be larger than capacity");
525
526 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
527 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
528
529 verify(r, !r->is_empty() || !r->has_live(),
530 "Empty regions should not have live data");
531
532 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
533 "Transitional: region flags and collection set agree");
534 }
535 };
536
537 class ShenandoahVerifierReachableTask : public WorkerTask {
538 private:
539 const char* _label;
540 ShenandoahVerifier::VerifyOptions _options;
541 ShenandoahHeap* _heap;
542 ShenandoahLivenessData* _ld;
543 MarkBitMap* _bitmap;
544 volatile size_t _processed;
545
546 public:
547 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
589 while (!stack.is_empty()) {
590 processed++;
591 ShenandoahVerifierTask task = stack.pop();
592 cl.verify_oops_from(task.obj());
593 }
594 }
595
596 Atomic::add(&_processed, processed, memory_order_relaxed);
597 }
598 };
599
600 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
601 private:
602 const char* _label;
603 ShenandoahVerifier::VerifyOptions _options;
604 ShenandoahHeap *_heap;
605 MarkBitMap* _bitmap;
606 ShenandoahLivenessData* _ld;
607 volatile size_t _claimed;
608 volatile size_t _processed;
609 ShenandoahGeneration* _generation;
610
611 public:
612 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
613 ShenandoahLivenessData* ld,
614 const char* label,
615 ShenandoahVerifier::VerifyOptions options) :
616 WorkerTask("Shenandoah Verifier Marked Objects"),
617 _label(label),
618 _options(options),
619 _heap(ShenandoahHeap::heap()),
620 _bitmap(bitmap),
621 _ld(ld),
622 _claimed(0),
623 _processed(0),
624 _generation(nullptr) {
625 if (_heap->mode()->is_generational()) {
626 _generation = _heap->active_generation();
627 assert(_generation != nullptr, "Expected active generation in this mode.");
628 }
629 };
630
631 size_t processed() {
632 return Atomic::load(&_processed);
633 }
634
635 virtual void work(uint worker_id) {
636 ShenandoahVerifierStack stack;
637 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
638 ShenandoahMessageBuffer("%s, Marked", _label),
639 _options);
640
641 while (true) {
642 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
643 if (v < _heap->num_regions()) {
644 ShenandoahHeapRegion* r = _heap->get_region(v);
645 if (!in_generation(r)) {
646 continue;
647 }
648
649 if (!r->is_humongous() && !r->is_trash()) {
650 work_regular(r, stack, cl);
651 } else if (r->is_humongous_start()) {
652 work_humongous(r, stack, cl);
653 }
654 } else {
655 break;
656 }
657 }
658 }
659
660 bool in_generation(ShenandoahHeapRegion* r) {
661 return _generation == nullptr || _generation->contains(r);
662 }
663
664 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
665 size_t processed = 0;
666 HeapWord* obj = r->bottom();
667 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
668 verify_and_follow(obj, stack, cl, &processed);
669 }
670 Atomic::add(&_processed, processed, memory_order_relaxed);
671 }
672
673 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
674 size_t processed = 0;
675 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
676 HeapWord* tams = ctx->top_at_mark_start(r);
677
678 // Bitmaps, before TAMS
679 if (tams > r->bottom()) {
680 HeapWord* start = r->bottom();
681 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
682
683 while (addr < tams) {
716 cl.verify_oops_from(obj);
717 (*processed)++;
718 }
719 while (!stack.is_empty()) {
720 ShenandoahVerifierTask task = stack.pop();
721 cl.verify_oops_from(task.obj());
722 (*processed)++;
723 }
724 }
725 };
726
727 class VerifyThreadGCState : public ThreadClosure {
728 private:
729 const char* const _label;
730 char const _expected;
731
732 public:
733 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
734 void do_thread(Thread* t) {
735 char actual = ShenandoahThreadLocalData::gc_state(t);
736 if (!verify_gc_state(actual, _expected)) {
737 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
738 }
739 }
740
741 static bool verify_gc_state(char actual, char expected) {
742 // Old generation marking is allowed in all states.
743 // TODO: This actually accepts more than just OLD_MARKING.
744 // TODO: Also, only accept OLD_MARKING in generational mode.
745 return (actual == expected) || (actual & ShenandoahHeap::OLD_MARKING);
746 }
747 };
748
749 void ShenandoahVerifier::verify_at_safepoint(const char* label,
750 VerifyRememberedSet remembered,
751 VerifyForwarded forwarded, VerifyMarked marked,
752 VerifyCollectionSet cset,
753 VerifyLiveness liveness, VerifyRegions regions,
754 VerifySize sizeness,
755 VerifyGCState gcstate) {
756 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
757 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
758
759 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
760 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
761
762 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
763
764 // GC state checks
765 {
766 char expected = -1;
767 bool enabled;
768 switch (gcstate) {
769 case _verify_gcstate_disable:
770 enabled = false;
771 break;
772 case _verify_gcstate_forwarded:
773 enabled = true;
774 expected = ShenandoahHeap::HAS_FORWARDED;
775 break;
776 case _verify_gcstate_evacuation:
777 enabled = true;
778 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
779 if (!_heap->is_stw_gc_in_progress()) {
780 // Only concurrent GC sets this.
781 expected |= ShenandoahHeap::WEAK_ROOTS;
782 }
783 break;
784 case _verify_gcstate_updating:
785 enabled = true;
786 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
787 break;
788 case _verify_gcstate_stable:
789 enabled = true;
790 expected = ShenandoahHeap::STABLE;
791 break;
792 case _verify_gcstate_stable_weakroots:
793 enabled = true;
794 expected = ShenandoahHeap::STABLE;
795 if (!_heap->is_stw_gc_in_progress()) {
796 // Only concurrent GC sets this.
797 expected |= ShenandoahHeap::WEAK_ROOTS;
798 }
799 break;
800 default:
801 enabled = false;
802 assert(false, "Unhandled gc-state verification");
803 }
804
805 if (enabled) {
806 char actual = _heap->gc_state();
807 // Old generation marking is allowed in all states.
808 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
809 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
810 }
811
812 VerifyThreadGCState vtgcs(label, expected);
813 Threads::java_threads_do(&vtgcs);
814 }
815 }
816
817 // Deactivate barriers temporarily: Verifier wants plain heap accesses
818 ShenandoahGCStateResetter resetter;
819
820 // Heap size checks
821 {
822 ShenandoahHeapLocker lock(_heap->lock());
823
824 ShenandoahCalculateRegionStatsClosure cl;
825 _heap->heap_region_iterate(&cl);
826 size_t heap_used;
827 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
828 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
829 heap_used = _heap->used() + _heap->get_pad_for_promote_in_place();
830 } else if (sizeness != _verify_size_disable) {
831 heap_used = _heap->used();
832 }
833 if (sizeness != _verify_size_disable) {
834 guarantee(cl.used() == heap_used,
835 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
836 label,
837 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
838 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
839 }
840 size_t heap_committed = _heap->committed();
841 guarantee(cl.committed() == heap_committed,
842 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
843 label,
844 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
845 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
846 }
847
848 log_debug(gc)("Safepoint verification finished heap usage verification");
849
850 ShenandoahGeneration* generation;
851 if (_heap->mode()->is_generational()) {
852 generation = _heap->active_generation();
853 guarantee(generation != nullptr, "Need to know which generation to verify.");
854 } else {
855 generation = nullptr;
856 }
857
858 if (generation != nullptr) {
859 ShenandoahHeapLocker lock(_heap->lock());
860
861 switch (remembered) {
862 case _verify_remembered_disable:
863 break;
864 case _verify_remembered_before_marking:
865 log_debug(gc)("Safepoint verification of remembered set at mark");
866 verify_rem_set_before_mark();
867 break;
868 case _verify_remembered_before_updating_references:
869 log_debug(gc)("Safepoint verification of remembered set at update ref");
870 verify_rem_set_before_update_ref();
871 break;
872 case _verify_remembered_after_full_gc:
873 log_debug(gc)("Safepoint verification of remembered set after full gc");
874 verify_rem_set_after_full_gc();
875 break;
876 default:
877 fatal("Unhandled remembered set verification mode");
878 }
879
880 ShenandoahGenerationStatsClosure cl;
881 _heap->heap_region_iterate(&cl);
882
883 if (LogTarget(Debug, gc)::is_enabled()) {
884 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
885 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
886 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
887 }
888 if (sizeness == _verify_size_adjusted_for_padding) {
889 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
890 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
891 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
892 } else if (sizeness == _verify_size_exact) {
893 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
894 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
895 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
896 }
897 // else: sizeness must equal _verify_size_disable
898 }
899
900 log_debug(gc)("Safepoint verification finished remembered set verification");
901
902 // Internal heap region checks
903 if (ShenandoahVerifyLevel >= 1) {
904 ShenandoahVerifyHeapRegionClosure cl(label, regions);
905 if (generation != nullptr) {
906 generation->heap_region_iterate(&cl);
907 } else {
908 _heap->heap_region_iterate(&cl);
909 }
910 }
911
912 log_debug(gc)("Safepoint verification finished heap region closure verification");
913
914 OrderAccess::fence();
915
916 if (UseTLAB) {
917 _heap->labs_make_parsable();
918 }
919
920 // Allocate temporary bitmap for storing marking wavefront:
921 _verification_bit_map->clear();
922
923 // Allocate temporary array for storing liveness data
924 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
925 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
926
927 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
928
929 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
930 // This verifies what application can see, since it only cares about reachable objects.
931 size_t count_reachable = 0;
932 if (ShenandoahVerifyLevel >= 2) {
933 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
934 _heap->workers()->run_task(&task);
935 count_reachable = task.processed();
936 }
937
938 log_debug(gc)("Safepoint verification finished getting initial reachable set");
939
940 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
941 // not the application, can see during the region scans. There is no reason to process the objects
942 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
943 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
944 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
945 // version
946
947 size_t count_marked = 0;
948 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
949 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
950 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
951 _heap->workers()->run_task(&task);
952 count_marked = task.processed();
953 } else {
954 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
955 }
956
957 log_debug(gc)("Safepoint verification finished walking marked objects");
958
959 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
960 // marked objects.
961
962 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
963 for (size_t i = 0; i < _heap->num_regions(); i++) {
964 ShenandoahHeapRegion* r = _heap->get_region(i);
965 if (generation != nullptr && !generation->contains(r)) {
966 continue;
967 }
968
969 juint verf_live = 0;
970 if (r->is_humongous()) {
971 // For humongous objects, test if start region is marked live, and if so,
972 // all humongous regions in that chain have live data equal to their "used".
973 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
974 if (start_live > 0) {
975 verf_live = (juint)(r->used() / HeapWordSize);
976 }
977 } else {
978 verf_live = Atomic::load(&ld[r->index()]);
979 }
980
981 size_t reg_live = r->get_live_data_words();
982 if (reg_live != verf_live) {
983 stringStream ss;
984 r->print_on(&ss);
985 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
986 label, reg_live, verf_live, ss.freeze());
987 }
988 }
989 }
990
991 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
992
993
994 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
995 label, ShenandoahVerifyLevel, count_reachable, count_marked);
996
997 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
998 }
999
1000 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1001 verify_at_safepoint(
1002 "Generic Verification",
1003 _verify_remembered_disable, // do not verify remembered set
1004 _verify_forwarded_allow, // conservatively allow forwarded
1005 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1006 _verify_cset_disable, // cset may be inconsistent
1007 _verify_liveness_disable, // no reliable liveness data
1008 _verify_regions_disable, // no reliable region data
1009 _verify_size_exact, // expect generation and heap sizes to match exactly
1010 _verify_gcstate_disable // no data about gcstate
1011 );
1012 }
1013
1014 void ShenandoahVerifier::verify_before_concmark() {
1015 verify_at_safepoint(
1016 "Before Mark",
1017 _verify_remembered_before_marking,
1018 // verify read-only remembered set from bottom() to top()
1019 _verify_forwarded_none, // UR should have fixed up
1020 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1021 _verify_cset_none, // UR should have fixed this
1022 _verify_liveness_disable, // no reliable liveness data
1023 _verify_regions_notrash, // no trash regions
1024 _verify_size_exact, // expect generation and heap sizes to match exactly
1025 _verify_gcstate_stable // there are no forwarded objects
1026 );
1027 }
1028
1029 void ShenandoahVerifier::verify_after_concmark() {
1030 verify_at_safepoint(
1031 "After Mark",
1032 _verify_remembered_disable, // do not verify remembered set
1033 _verify_forwarded_none, // no forwarded references
1034 _verify_marked_complete_except_references,
1035 // bitmaps as precise as we can get, except dangling j.l.r.Refs
1036 _verify_cset_none, // no references to cset anymore
1037 _verify_liveness_complete, // liveness data must be complete here
1038 _verify_regions_disable, // trash regions not yet recycled
1039 _verify_size_exact, // expect generation and heap sizes to match exactly
1040 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1041 );
1042 }
1043
1044 void ShenandoahVerifier::verify_before_evacuation() {
1045 verify_at_safepoint(
1046 "Before Evacuation",
1047 _verify_remembered_disable, // do not verify remembered set
1048 _verify_forwarded_none, // no forwarded references
1049 _verify_marked_complete_except_references, // walk over marked objects too
1050 _verify_cset_disable, // non-forwarded references to cset expected
1051 _verify_liveness_complete, // liveness data must be complete here
1052 _verify_regions_disable, // trash regions not yet recycled
1053 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1054 // for promote in place padding
1055 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1056 );
1057 }
1058
1059 void ShenandoahVerifier::verify_during_evacuation() {
1060 verify_at_safepoint(
1061 "During Evacuation",
1062 _verify_remembered_disable, // do not verify remembered set
1063 _verify_forwarded_allow, // some forwarded references are allowed
1064 _verify_marked_disable, // walk only roots
1065 _verify_cset_disable, // some cset references are not forwarded yet
1066 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1067 _verify_regions_disable, // trash regions not yet recycled
1068 _verify_size_disable, // we don't know how much of promote-in-place work has been completed
1069 _verify_gcstate_evacuation // evacuation is in progress
1070 );
1071 }
1072
1073 void ShenandoahVerifier::verify_after_evacuation() {
1074 verify_at_safepoint(
1075 "After Evacuation",
1076 _verify_remembered_disable, // do not verify remembered set
1077 _verify_forwarded_allow, // objects are still forwarded
1078 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1079 _verify_cset_forwarded, // all cset refs are fully forwarded
1080 _verify_liveness_disable, // no reliable liveness data anymore
1081 _verify_regions_notrash, // trash regions have been recycled already
1082 _verify_size_exact, // expect generation and heap sizes to match exactly
1083 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1084 );
1085 }
1086
1087 void ShenandoahVerifier::verify_before_updaterefs() {
1088 verify_at_safepoint(
1089 "Before Updating References",
1090 _verify_remembered_before_updating_references, // verify read-write remembered set
1091 _verify_forwarded_allow, // forwarded references allowed
1092 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1093 _verify_cset_forwarded, // all cset refs are fully forwarded
1094 _verify_liveness_disable, // no reliable liveness data anymore
1095 _verify_regions_notrash, // trash regions have been recycled already
1096 _verify_size_exact, // expect generation and heap sizes to match exactly
1097 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1098 );
1099 }
1100
1101 // We have not yet cleanup (reclaimed) the collection set
1102 void ShenandoahVerifier::verify_after_updaterefs() {
1103 verify_at_safepoint(
1104 "After Updating References",
1105 _verify_remembered_disable, // do not verify remembered set
1106 _verify_forwarded_none, // no forwarded references
1107 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1108 _verify_cset_none, // no cset references, all updated
1109 _verify_liveness_disable, // no reliable liveness data anymore
1110 _verify_regions_nocset, // no cset regions, trash regions have appeared
1111 _verify_size_exact, // expect generation and heap sizes to match exactly
1112 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1113 );
1114 }
1115
1116 void ShenandoahVerifier::verify_after_degenerated() {
1117 verify_at_safepoint(
1118 "After Degenerated GC",
1119 _verify_remembered_disable, // do not verify remembered set
1120 _verify_forwarded_none, // all objects are non-forwarded
1121 _verify_marked_complete, // all objects are marked in complete bitmap
1122 _verify_cset_none, // no cset references
1123 _verify_liveness_disable, // no reliable liveness data anymore
1124 _verify_regions_notrash_nocset, // no trash, no cset
1125 _verify_size_exact, // expect generation and heap sizes to match exactly
1126 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1127 );
1128 }
1129
1130 void ShenandoahVerifier::verify_before_fullgc() {
1131 verify_at_safepoint(
1132 "Before Full GC",
1133 _verify_remembered_disable, // do not verify remembered set
1134 _verify_forwarded_allow, // can have forwarded objects
1135 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1136 _verify_cset_disable, // cset might be foobared
1137 _verify_liveness_disable, // no reliable liveness data anymore
1138 _verify_regions_disable, // no reliable region data here
1139 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1140 _verify_gcstate_disable // no reliable gcstate data
1141 );
1142 }
1143
1144 void ShenandoahVerifier::verify_after_fullgc() {
1145 verify_at_safepoint(
1146 "After Full GC",
1147 _verify_remembered_after_full_gc, // verify read-write remembered set
1148 _verify_forwarded_none, // all objects are non-forwarded
1149 _verify_marked_complete, // all objects are marked in complete bitmap
1150 _verify_cset_none, // no cset references
1151 _verify_liveness_disable, // no reliable liveness data anymore
1152 _verify_regions_notrash_nocset, // no trash, no cset
1153 _verify_size_exact, // expect generation and heap sizes to match exactly
1154 _verify_gcstate_stable // full gc cleaned up everything
1155 );
1156 }
1157
1158 // TODO: Why this closure does not visit metadata?
1159 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1160 private:
1161 template <class T>
1162 void do_oop_work(T* p) {
1163 T o = RawAccess<>::oop_load(p);
1164 if (!CompressedOops::is_null(o)) {
1165 oop obj = CompressedOops::decode_not_null(o);
1166 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1167 if (obj != fwd) {
1168 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1169 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1170 }
1171 }
1172 }
1173
1174 public:
1175 void do_oop(narrowOop* p) { do_oop_work(p); }
1176 void do_oop(oop* p) { do_oop_work(p); }
1177 };
1178
1179 // TODO: Why this closure does not visit metadata?
1180 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1181 private:
1182 template <class T>
1183 void do_oop_work(T* p) {
1184 T o = RawAccess<>::oop_load(p);
1185 if (!CompressedOops::is_null(o)) {
1186 oop obj = CompressedOops::decode_not_null(o);
1187 ShenandoahHeap* heap = ShenandoahHeap::heap();
1188
1189 if (!heap->marking_context()->is_marked_or_old(obj)) {
1190 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1191 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1192 }
1193
1194 if (heap->in_collection_set(obj)) {
1195 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1196 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1197 }
1198
1199 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1200 if (obj != fwd) {
1201 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1202 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1203 }
1204 }
1205 }
1206
1207 public:
1208 void do_oop(narrowOop* p) { do_oop_work(p); }
1209 void do_oop(oop* p) { do_oop_work(p); }
1210 };
1211
1212 void ShenandoahVerifier::verify_roots_in_to_space() {
1213 ShenandoahVerifyInToSpaceClosure cl;
1214 ShenandoahRootVerifier::roots_do(&cl);
1215 }
1216
1217 void ShenandoahVerifier::verify_roots_no_forwarded() {
1218 ShenandoahVerifyNoForwared cl;
1219 ShenandoahRootVerifier::roots_do(&cl);
1220 }
1221
1222 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1223 protected:
1224 bool const _init_mark;
1225 ShenandoahHeap* const _heap;
1226 RememberedScanner* const _scanner;
1227
1228 public:
1229 // Argument distinguishes between initial mark or start of update refs verification.
1230 ShenandoahVerifyRemSetClosure(bool init_mark) :
1231 _init_mark(init_mark),
1232 _heap(ShenandoahHeap::heap()),
1233 _scanner(_heap->card_scan()) {}
1234
1235 template<class T>
1236 inline void work(T* p) {
1237 T o = RawAccess<>::oop_load(p);
1238 if (!CompressedOops::is_null(o)) {
1239 oop obj = CompressedOops::decode_not_null(o);
1240 if (_heap->is_in_young(obj)) {
1241 size_t card_index = _scanner->card_index_for_addr((HeapWord*) p);
1242 if (_init_mark && !_scanner->is_card_dirty(card_index)) {
1243 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1244 "Verify init-mark remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1245 } else if (!_init_mark && !_scanner->is_write_card_dirty(card_index)) {
1246 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1247 "Verify init-update-refs remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1248 }
1249 }
1250 }
1251 }
1252
1253 virtual void do_oop(narrowOop* p) { work(p); }
1254 virtual void do_oop(oop* p) { work(p); }
1255 };
1256
1257 void ShenandoahVerifier::help_verify_region_rem_set(ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx, HeapWord* from,
1258 HeapWord* top, HeapWord* registration_watermark, const char* message) {
1259 RememberedScanner* scanner = _heap->card_scan();
1260 ShenandoahVerifyRemSetClosure check_interesting_pointers(false);
1261
1262 HeapWord* obj_addr = from;
1263 if (r->is_humongous_start()) {
1264 oop obj = cast_to_oop(obj_addr);
1265 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1266 size_t card_index = scanner->card_index_for_addr(obj_addr);
1267 // For humongous objects, the typical object is an array, so the following checks may be overkill
1268 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1269 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1270 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1271 obj->oop_iterate(&check_interesting_pointers);
1272 }
1273 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1274 }
1275 // else, this humongous object is not live so no need to verify its internal pointers
1276
1277 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1278 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1279 "object not properly registered", __FILE__, __LINE__);
1280 }
1281 } else if (!r->is_humongous()) {
1282 while (obj_addr < top) {
1283 oop obj = cast_to_oop(obj_addr);
1284 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1285 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1286 size_t card_index = scanner->card_index_for_addr(obj_addr);
1287 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1288 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1289 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1290 obj->oop_iterate(&check_interesting_pointers);
1291 }
1292 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1293
1294 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1295 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1296 "object not properly registered", __FILE__, __LINE__);
1297 }
1298 obj_addr += obj->size();
1299 } else {
1300 // This object is not live so we don't verify dirty cards contained therein
1301 HeapWord* tams = ctx->top_at_mark_start(r);
1302 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1303 }
1304 }
1305 }
1306 }
1307
1308 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1309 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1310 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1311 // restore them until the start of evacuation.
1312 void ShenandoahVerifier::verify_rem_set_before_mark() {
1313 shenandoah_assert_safepoint();
1314 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1315
1316 ShenandoahRegionIterator iterator;
1317 RememberedScanner* scanner = _heap->card_scan();
1318 ShenandoahVerifyRemSetClosure check_interesting_pointers(true);
1319 ShenandoahMarkingContext* ctx;
1320
1321 log_debug(gc)("Verifying remembered set at %s mark", _heap->doing_mixed_evacuations()? "mixed": "young");
1322
1323 if (_heap->is_old_bitmap_stable() || _heap->active_generation()->is_global()) {
1324 ctx = _heap->complete_marking_context();
1325 } else {
1326 ctx = nullptr;
1327 }
1328
1329 while (iterator.has_next()) {
1330 ShenandoahHeapRegion* r = iterator.next();
1331 if (r == nullptr) {
1332 // TODO: Can this really happen?
1333 break;
1334 }
1335
1336 HeapWord* tams = (ctx != nullptr) ? ctx->top_at_mark_start(r) : nullptr;
1337
1338 // TODO: Is this replaceable with call to help_verify_region_rem_set?
1339
1340 if (r->is_old() && r->is_active()) {
1341 HeapWord* obj_addr = r->bottom();
1342 if (r->is_humongous_start()) {
1343 oop obj = cast_to_oop(obj_addr);
1344 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1345 // For humongous objects, the typical object is an array, so the following checks may be overkill
1346 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1347 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1348 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1349 obj->oop_iterate(&check_interesting_pointers);
1350 }
1351 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1352 }
1353 // else, this humongous object is not marked so no need to verify its internal pointers
1354 if (!scanner->verify_registration(obj_addr, ctx)) {
1355 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1356 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1357 }
1358 } else if (!r->is_humongous()) {
1359 HeapWord* top = r->top();
1360 while (obj_addr < top) {
1361 oop obj = cast_to_oop(obj_addr);
1362 // ctx->is_marked() returns true if mark bit set (TAMS not relevant during init mark)
1363 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1364 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1365 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1366 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1367 obj->oop_iterate(&check_interesting_pointers);
1368 }
1369 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1370 if (!scanner->verify_registration(obj_addr, ctx)) {
1371 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1372 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1373 }
1374 obj_addr += obj->size();
1375 } else {
1376 // This object is not live so we don't verify dirty cards contained therein
1377 assert(tams != nullptr, "If object is not live, ctx and tams should be non-null");
1378 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1379 }
1380 }
1381 } // else, we ignore humongous continuation region
1382 } // else, this is not an OLD region so we ignore it
1383 } // all regions have been processed
1384 }
1385
1386 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1387 shenandoah_assert_safepoint();
1388 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1389
1390 ShenandoahRegionIterator iterator;
1391
1392 while (iterator.has_next()) {
1393 ShenandoahHeapRegion* r = iterator.next();
1394 if (r == nullptr) {
1395 // TODO: Can this really happen?
1396 break;
1397 }
1398 if (r->is_old() && !r->is_cset()) {
1399 help_verify_region_rem_set(r, nullptr, r->bottom(), r->top(), r->top(), "Remembered set violation at end of Full GC");
1400 }
1401 }
1402 }
1403
1404 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1405 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1406 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1407 // all PLABS are retired immediately before the start of update refs.
1408 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1409 shenandoah_assert_safepoint();
1410 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1411
1412 ShenandoahRegionIterator iterator;
1413 ShenandoahMarkingContext* ctx;
1414
1415 if (_heap->is_old_bitmap_stable() || _heap->active_generation()->is_global()) {
1416 ctx = _heap->complete_marking_context();
1417 } else {
1418 ctx = nullptr;
1419 }
1420
1421 while (iterator.has_next()) {
1422 ShenandoahHeapRegion* r = iterator.next();
1423 if (r == nullptr) {
1424 // TODO: Can this really happen?
1425 break;
1426 }
1427 if (r->is_old() && !r->is_cset()) {
1428 help_verify_region_rem_set(r, ctx, r->bottom(), r->top(), r->get_update_watermark(),
1429 "Remembered set violation at init-update-references");
1430 }
1431 }
1432 }
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