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