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 "utilities/align.hpp"
43
44 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
45 #ifdef verify_oop
46 #undef verify_oop
47 #endif
48
49 static bool is_instance_ref_klass(Klass* k) {
50 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
51 }
52
53 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
54 public:
55 virtual bool discover_reference(oop obj, ReferenceType type) {
56 return true;
57 }
58 };
59
60 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
61 private:
62 const char* _phase;
63 ShenandoahVerifier::VerifyOptions _options;
64 ShenandoahVerifierStack* _stack;
65 ShenandoahHeap* _heap;
66 MarkBitMap* _map;
67 ShenandoahLivenessData* _ld;
68 void* _interior_loc;
69 oop _loc;
70
71 public:
72 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
73 const char* phase, ShenandoahVerifier::VerifyOptions options) :
74 _phase(phase),
75 _options(options),
76 _stack(stack),
77 _heap(ShenandoahHeap::heap()),
78 _map(map),
79 _ld(ld),
80 _interior_loc(NULL),
81 _loc(NULL) {
82 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
83 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
84 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
85 }
86 }
87
88 private:
89 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
90 if (!test) {
91 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
92 }
93 }
94
95 template <class T>
96 void do_oop_work(T* p) {
97 T o = RawAccess<>::oop_load(p);
98 if (!CompressedOops::is_null(o)) {
99 oop obj = CompressedOops::decode_not_null(o);
100 if (is_instance_ref_klass(obj->forward_safe_klass())) {
101 obj = ShenandoahForwarding::get_forwardee(obj);
102 }
103 // Single threaded verification can use faster non-atomic stack and bitmap
104 // methods.
105 //
106 // For performance reasons, only fully verify non-marked field values.
107 // We are here when the host object for *p is already marked.
108
109 if (_map->par_mark(obj)) {
110 verify_oop_at(p, obj);
111 _stack->push(ShenandoahVerifierTask(obj));
112 }
113 }
114 }
115
116 void verify_oop(oop obj) {
117 // Perform consistency checks with gradually decreasing safety level. This guarantees
118 // that failure report would not try to touch something that was not yet verified to be
119 // safe to process.
120
121 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
122 "oop must be in heap");
123 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
124 "oop must be aligned");
125
126 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
127 Klass* obj_klass = obj->forward_safe_klass();
128
129 // Verify that obj is not in dead space:
130 {
131 // Do this before touching obj->size()
132 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
133 "Object klass pointer should not be NULL");
134 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
135 "Object klass pointer must go to metaspace");
136
137 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
138 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
139 "Object start should be within the region");
140
141 if (!obj_reg->is_humongous()) {
142 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->forward_safe_size()) <= obj_reg->top(),
143 "Object end should be within the region");
144 } else {
145 size_t humongous_start = obj_reg->index();
146 size_t humongous_end = humongous_start + (obj->forward_safe_size() >> ShenandoahHeapRegion::region_size_words_shift());
147 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
148 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
149 "Humongous object is in continuation that fits it");
150 }
151 }
152
153 // ------------ obj is safe at this point --------------
154
155 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
156 "Object should be in active region");
157
158 switch (_options._verify_liveness) {
159 case ShenandoahVerifier::_verify_liveness_disable:
160 // skip
161 break;
162 case ShenandoahVerifier::_verify_liveness_complete:
163 Atomic::add(&_ld[obj_reg->index()], (uint) obj->forward_safe_size(), memory_order_relaxed);
164 // fallthrough for fast failure for un-live regions:
165 case ShenandoahVerifier::_verify_liveness_conservative:
166 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
167 "Object must belong to region with live data");
168 break;
169 default:
170 assert(false, "Unhandled liveness verification");
171 }
172 }
173
174 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
175
176 ShenandoahHeapRegion* fwd_reg = NULL;
177
178 if (obj != fwd) {
179 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
180 "Forwardee must be in heap");
181 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
182 "Forwardee is set");
183 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
184 "Forwardee must be aligned");
185
186 // Do this before touching fwd->size()
187 Klass* fwd_klass = fwd->klass_or_null();
188 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
189 "Forwardee klass pointer should not be NULL");
190 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
191 "Forwardee klass pointer must go to metaspace");
192 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
193 "Forwardee klass pointer must go to metaspace");
194
195 fwd_reg = _heap->heap_region_containing(fwd);
196
197 // Verify that forwardee is not in the dead space:
198 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
199 "Should have no humongous forwardees");
200
201 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
202 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
203 "Forwardee start should be within the region");
204 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->forward_safe_size()) <= fwd_reg->top(),
205 "Forwardee end should be within the region");
206
207 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
208 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
209 "Double forwarding");
210 } else {
211 fwd_reg = obj_reg;
212 }
213
214 // ------------ obj and fwd are safe at this point --------------
215
216 switch (_options._verify_marked) {
217 case ShenandoahVerifier::_verify_marked_disable:
218 // skip
219 break;
220 case ShenandoahVerifier::_verify_marked_incomplete:
221 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
222 "Must be marked in incomplete bitmap");
223 break;
224 case ShenandoahVerifier::_verify_marked_complete:
225 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
226 "Must be marked in complete bitmap");
227 break;
228 case ShenandoahVerifier::_verify_marked_complete_except_references:
229 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
230 "Must be marked in complete bitmap, except j.l.r.Reference referents");
231 break;
232 default:
233 assert(false, "Unhandled mark verification");
234 }
235
236 switch (_options._verify_forwarded) {
237 case ShenandoahVerifier::_verify_forwarded_disable:
238 // skip
239 break;
240 case ShenandoahVerifier::_verify_forwarded_none: {
241 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
242 "Should not be forwarded");
243 break;
244 }
245 case ShenandoahVerifier::_verify_forwarded_allow: {
246 if (obj != fwd) {
247 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
248 "Forwardee should be in another region");
249 }
250 break;
251 }
252 default:
253 assert(false, "Unhandled forwarding verification");
254 }
255
256 switch (_options._verify_cset) {
257 case ShenandoahVerifier::_verify_cset_disable:
258 // skip
259 break;
260 case ShenandoahVerifier::_verify_cset_none:
261 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
262 "Should not have references to collection set");
263 break;
264 case ShenandoahVerifier::_verify_cset_forwarded:
265 if (_heap->in_collection_set(obj)) {
266 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
267 "Object in collection set, should have forwardee");
268 }
269 break;
270 default:
271 assert(false, "Unhandled cset verification");
272 }
273
274 }
275
276 public:
277 /**
278 * Verify object with known interior reference.
279 * @param p interior reference where the object is referenced from; can be off-heap
280 * @param obj verified object
281 */
282 template <class T>
283 void verify_oop_at(T* p, oop obj) {
284 _interior_loc = p;
285 verify_oop(obj);
286 _interior_loc = NULL;
287 }
288
289 /**
290 * Verify object without known interior reference.
291 * Useful when picking up the object at known offset in heap,
292 * but without knowing what objects reference it.
293 * @param obj verified object
294 */
295 void verify_oop_standalone(oop obj) {
296 _interior_loc = NULL;
297 verify_oop(obj);
298 _interior_loc = NULL;
299 }
300
301 /**
302 * Verify oop fields from this object.
303 * @param obj host object for verified fields
304 */
305 void verify_oops_from(oop obj) {
306 _loc = obj;
307 Klass* klass = obj->forward_safe_klass();
308 obj->oop_iterate_backwards(this, klass);
309 _loc = NULL;
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);
351 msg.append("%s", ss.as_string());
352
353 report_vm_error(__FILE__, __LINE__, msg.buffer());
354 }
355
356 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
357 if (!test) {
358 print_failure(r, msg);
359 }
360 }
361
362 void heap_region_do(ShenandoahHeapRegion* r) {
363 switch (_regions) {
364 case ShenandoahVerifier::_verify_regions_disable:
365 break;
366 case ShenandoahVerifier::_verify_regions_notrash:
367 verify(r, !r->is_trash(),
368 "Should not have trash regions");
369 break;
370 case ShenandoahVerifier::_verify_regions_nocset:
371 verify(r, !r->is_cset(),
372 "Should not have cset regions");
373 break;
374 case ShenandoahVerifier::_verify_regions_notrash_nocset:
375 verify(r, !r->is_trash(),
376 "Should not have trash regions");
377 verify(r, !r->is_cset(),
378 "Should not have cset regions");
379 break;
380 default:
381 ShouldNotReachHere();
382 }
383
384 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
385 "Capacity should match region size");
386
387 verify(r, r->bottom() <= r->top(),
388 "Region top should not be less than bottom");
389
390 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
391 "Region TAMS should not be less than bottom");
392
393 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
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 AbstractGangTask {
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,
436 ShenandoahLivenessData* ld,
437 const char* label,
438 ShenandoahVerifier::VerifyOptions options) :
439 AbstractGangTask("Shenandoah Verifier Reachable Objects"),
440 _label(label),
441 _options(options),
442 _heap(ShenandoahHeap::heap()),
443 _ld(ld),
444 _bitmap(bitmap),
445 _processed(0) {};
446
447 size_t processed() {
448 return _processed;
449 }
450
451 virtual void work(uint worker_id) {
452 ResourceMark rm;
453 ShenandoahVerifierStack stack;
454
455 // On level 2, we need to only check the roots once.
456 // On level 3, we want to check the roots, and seed the local stack.
457 // It is a lesser evil to accept multiple root scans at level 3, because
458 // extended parallelism would buy us out.
459 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
460 || (ShenandoahVerifyLevel >= 3)) {
461 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
462 ShenandoahMessageBuffer("%s, Roots", _label),
463 _options);
464 if (_heap->unload_classes()) {
465 ShenandoahRootVerifier::strong_roots_do(&cl);
466 } else {
467 ShenandoahRootVerifier::roots_do(&cl);
468 }
469 }
470
471 size_t processed = 0;
472
473 if (ShenandoahVerifyLevel >= 3) {
474 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
475 ShenandoahMessageBuffer("%s, Reachable", _label),
476 _options);
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 AbstractGangTask {
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 AbstractGangTask("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_and_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) {
557 verify_and_follow(addr, stack, cl, &processed);
558 addr += 1;
559 if (addr < tams) {
560 addr = ctx->get_next_marked_addr(addr, tams);
561 }
562 }
563 }
564
565 // Size-based, after TAMS
566 {
567 HeapWord* limit = r->top();
568 HeapWord* addr = tams;
569
570 while (addr < limit) {
571 verify_and_follow(addr, stack, cl, &processed);
572 addr += cast_to_oop(addr)->size();
573 }
574 }
575
576 Atomic::add(&_processed, processed, memory_order_relaxed);
577 }
578
579 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
580 if (!_bitmap->par_mark(addr)) return;
581
582 // Verify the object itself:
583 oop obj = cast_to_oop(addr);
584 cl.verify_oop_standalone(obj);
585
586 // Verify everything reachable from that object too, hopefully realizing
587 // everything was already marked, and never touching further:
588 if (!is_instance_ref_klass(obj->forward_safe_klass())) {
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 ShenandoahHeap::heap()->set_gc_state_all_threads();
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 ResourceMark rm;
771 stringStream ss;
772 r->print_on(&ss);
773 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
774 label, reg_live, verf_live, ss.as_string());
775 }
776 }
777 }
778
779 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
780 label, ShenandoahVerifyLevel, count_reachable, count_marked);
781
782 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
783 }
784
785 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
786 verify_at_safepoint(
787 "Generic Verification",
788 _verify_forwarded_allow, // conservatively allow forwarded
789 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
790 _verify_cset_disable, // cset may be inconsistent
791 _verify_liveness_disable, // no reliable liveness data
792 _verify_regions_disable, // no reliable region data
793 _verify_gcstate_disable // no data about gcstate
794 );
795 }
796
797 void ShenandoahVerifier::verify_before_concmark() {
798 verify_at_safepoint(
799 "Before Mark",
800 _verify_forwarded_none, // UR should have fixed up
801 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
802 _verify_cset_none, // UR should have fixed this
803 _verify_liveness_disable, // no reliable liveness data
804 _verify_regions_notrash, // no trash regions
805 _verify_gcstate_stable // there are no forwarded objects
806 );
807 }
808
809 void ShenandoahVerifier::verify_after_concmark() {
810 verify_at_safepoint(
811 "After Mark",
812 _verify_forwarded_none, // no forwarded references
813 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
814 _verify_cset_none, // no references to cset anymore
815 _verify_liveness_complete, // liveness data must be complete here
816 _verify_regions_disable, // trash regions not yet recycled
817 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
818 );
819 }
820
821 void ShenandoahVerifier::verify_before_evacuation() {
822 verify_at_safepoint(
823 "Before Evacuation",
824 _verify_forwarded_none, // no forwarded references
825 _verify_marked_complete_except_references, // walk over marked objects too
826 _verify_cset_disable, // non-forwarded references to cset expected
827 _verify_liveness_complete, // liveness data must be complete here
828 _verify_regions_disable, // trash regions not yet recycled
829 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
830 );
831 }
832
833 void ShenandoahVerifier::verify_during_evacuation() {
834 verify_at_safepoint(
835 "During Evacuation",
836 _verify_forwarded_allow, // some forwarded references are allowed
837 _verify_marked_disable, // walk only roots
838 _verify_cset_disable, // some cset references are not forwarded yet
839 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
840 _verify_regions_disable, // trash regions not yet recycled
841 _verify_gcstate_evacuation // evacuation is in progress
842 );
843 }
844
845 void ShenandoahVerifier::verify_after_evacuation() {
846 verify_at_safepoint(
847 "After Evacuation",
848 _verify_forwarded_allow, // objects are still forwarded
849 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
850 _verify_cset_forwarded, // all cset refs are fully forwarded
851 _verify_liveness_disable, // no reliable liveness data anymore
852 _verify_regions_notrash, // trash regions have been recycled already
853 _verify_gcstate_forwarded // evacuation produced some forwarded objects
854 );
855 }
856
857 void ShenandoahVerifier::verify_before_updaterefs() {
858 verify_at_safepoint(
859 "Before Updating References",
860 _verify_forwarded_allow, // forwarded references allowed
861 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
862 _verify_cset_forwarded, // all cset refs are fully forwarded
863 _verify_liveness_disable, // no reliable liveness data anymore
864 _verify_regions_notrash, // trash regions have been recycled already
865 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
866 );
867 }
868
869 void ShenandoahVerifier::verify_after_updaterefs() {
870 verify_at_safepoint(
871 "After Updating References",
872 _verify_forwarded_none, // no forwarded references
873 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
874 _verify_cset_none, // no cset references, all updated
875 _verify_liveness_disable, // no reliable liveness data anymore
876 _verify_regions_nocset, // no cset regions, trash regions have appeared
877 _verify_gcstate_stable // update refs had cleaned up forwarded objects
878 );
879 }
880
881 void ShenandoahVerifier::verify_after_degenerated() {
882 verify_at_safepoint(
883 "After Degenerated GC",
884 _verify_forwarded_none, // all objects are non-forwarded
885 _verify_marked_complete, // all objects are marked in complete bitmap
886 _verify_cset_none, // no cset references
887 _verify_liveness_disable, // no reliable liveness data anymore
888 _verify_regions_notrash_nocset, // no trash, no cset
889 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
890 );
891 }
892
893 void ShenandoahVerifier::verify_before_fullgc() {
894 verify_at_safepoint(
895 "Before Full GC",
896 _verify_forwarded_allow, // can have forwarded objects
897 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
898 _verify_cset_disable, // cset might be foobared
899 _verify_liveness_disable, // no reliable liveness data anymore
900 _verify_regions_disable, // no reliable region data here
901 _verify_gcstate_disable // no reliable gcstate data
902 );
903 }
904
905 void ShenandoahVerifier::verify_after_fullgc() {
906 verify_at_safepoint(
907 "After Full GC",
908 _verify_forwarded_none, // all objects are non-forwarded
909 _verify_marked_complete, // all objects are marked in complete bitmap
910 _verify_cset_none, // no cset references
911 _verify_liveness_disable, // no reliable liveness data anymore
912 _verify_regions_notrash_nocset, // no trash, no cset
913 _verify_gcstate_stable // full gc cleaned up everything
914 );
915 }
916
917 class ShenandoahVerifyNoForwared : public OopClosure {
918 private:
919 template <class T>
920 void do_oop_work(T* p) {
921 T o = RawAccess<>::oop_load(p);
922 if (!CompressedOops::is_null(o)) {
923 oop obj = CompressedOops::decode_not_null(o);
924 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
925 if (obj != fwd) {
926 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
927 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
928 }
929 }
930 }
931
932 public:
933 void do_oop(narrowOop* p) { do_oop_work(p); }
934 void do_oop(oop* p) { do_oop_work(p); }
935 };
936
937 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
938 private:
939 template <class T>
940 void do_oop_work(T* p) {
941 T o = RawAccess<>::oop_load(p);
942 if (!CompressedOops::is_null(o)) {
943 oop obj = CompressedOops::decode_not_null(o);
944 ShenandoahHeap* heap = ShenandoahHeap::heap();
945
946 if (!heap->marking_context()->is_marked(obj)) {
947 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
948 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
949 }
950
951 if (heap->in_collection_set(obj)) {
952 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
953 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
954 }
955
956 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
957 if (obj != fwd) {
958 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
959 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
960 }
961 }
962 }
963
964 public:
965 void do_oop(narrowOop* p) { do_oop_work(p); }
966 void do_oop(oop* p) { do_oop_work(p); }
967 };
968
969 void ShenandoahVerifier::verify_roots_in_to_space() {
970 ShenandoahVerifyInToSpaceClosure cl;
971 ShenandoahRootVerifier::roots_do(&cl);
972 }
973
974 void ShenandoahVerifier::verify_roots_no_forwarded() {
975 ShenandoahVerifyNoForwared cl;
976 ShenandoahRootVerifier::roots_do(&cl);
977 }