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