1 /*
2 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25
26 #include "gc_implementation/shenandoah/shenandoahAsserts.hpp"
27 #include "gc_implementation/shenandoah/shenandoahForwarding.hpp"
28 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
29 #include "gc_implementation/shenandoah/shenandoahHeapRegion.inline.hpp"
30 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp"
31 #include "gc_implementation/shenandoah/shenandoahUtils.hpp"
32 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp"
33 #include "gc_implementation/shenandoah/shenandoahWorkGroup.hpp"
34 #include "memory/allocation.hpp"
35 #include "memory/resourceArea.hpp"
36
37 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
38 #ifdef verify_oop
39 #undef verify_oop
40 #endif
41
42 class ShenandoahVerifyOopClosure : public ExtendedOopClosure {
43 private:
44 const char* _phase;
45 ShenandoahVerifier::VerifyOptions _options;
46 ShenandoahVerifierStack* _stack;
47 ShenandoahHeap* _heap;
48 MarkBitMap* _map;
49 ShenandoahLivenessData* _ld;
50 void* _interior_loc;
51 oop _loc;
52
53 public:
54 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
55 const char* phase, ShenandoahVerifier::VerifyOptions options) :
56 _phase(phase),
57 _options(options),
58 _stack(stack),
59 _heap(ShenandoahHeap::heap()),
60 _map(map),
61 _ld(ld),
62 _interior_loc(NULL),
63 _loc(NULL) { }
64
65 private:
66 void verify(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
67 if (!test) {
68 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
69 }
70 }
71
72 template <class T>
73 void do_oop_work(T* p) {
74 T o = oopDesc::load_heap_oop(p);
75 if (!oopDesc::is_null(o)) {
76 oop obj = oopDesc::decode_heap_oop_not_null(o);
77
78 // Single threaded verification can use faster non-atomic stack and bitmap
79 // methods.
80 //
81 // For performance reasons, only fully verify non-marked field values.
82 // We are here when the host object for *p is already marked.
83
84 HeapWord* addr = (HeapWord*) obj;
85 if (_map->parMark(addr)) {
86 verify_oop_at(p, obj);
87 _stack->push(ShenandoahVerifierTask(obj));
88 }
89 }
90 }
91
92 void verify_oop(oop obj) {
93 // Perform consistency checks with gradually decreasing safety level. This guarantees
94 // that failure report would not try to touch something that was not yet verified to be
95 // safe to process.
96
97 verify(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
98 "oop must be in heap");
99 verify(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),
100 "oop must be aligned");
101
102 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
103 Klass* obj_klass = obj->klass_or_null();
104
105 // Verify that obj is not in dead space:
106 {
107 // Do this before touching obj->size()
108 verify(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,
109 "Object klass pointer should not be NULL");
110 verify(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
111 "Object klass pointer must go to metaspace");
112
113 HeapWord *obj_addr = (HeapWord *) obj;
114 verify(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
115 "Object start should be within the region");
116
117 if (!obj_reg->is_humongous()) {
118 verify(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
119 "Object end should be within the region");
120 } else {
121 size_t humongous_start = obj_reg->index();
122 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
123 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
124 verify(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
125 "Humongous object is in continuation that fits it");
126 }
127 }
128
129 // ------------ obj is safe at this point --------------
130
131 verify(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
132 "Object should be in active region");
133
134 switch (_options._verify_liveness) {
135 case ShenandoahVerifier::_verify_liveness_disable:
136 // skip
137 break;
138 case ShenandoahVerifier::_verify_liveness_complete:
139 Atomic::add((uint) obj->size(), &_ld[obj_reg->index()]);
140 // fallthrough for fast failure for un-live regions:
141 case ShenandoahVerifier::_verify_liveness_conservative:
142 verify(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
143 "Object must belong to region with live data");
144 break;
145 default:
146 assert(false, "Unhandled liveness verification");
147 }
148 }
149
150 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
151
152 ShenandoahHeapRegion* fwd_reg = NULL;
153
154 if (obj != fwd) {
155 verify(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
156 "Forwardee must be in heap");
157 verify(ShenandoahAsserts::_safe_oop, obj, !oopDesc::is_null(fwd),
158 "Forwardee is set");
159 verify(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),
160 "Forwardee must be aligned");
161
162 // Do this before touching fwd->size()
163 Klass* fwd_klass = fwd->klass_or_null();
164 verify(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,
165 "Forwardee klass pointer should not be NULL");
166 verify(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
167 "Forwardee klass pointer must go to metaspace");
168 verify(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
169 "Forwardee klass pointer must go to metaspace");
170
171 fwd_reg = _heap->heap_region_containing(fwd);
172
173 // Verify that forwardee is not in the dead space:
174 verify(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
175 "Should have no humongous forwardees");
176
177 HeapWord *fwd_addr = (HeapWord *) fwd;
178 verify(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
179 "Forwardee start should be within the region");
180 verify(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
181 "Forwardee end should be within the region");
182
183 oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
184 verify(ShenandoahAsserts::_safe_oop, obj, fwd == fwd2,
185 "Double forwarding");
186 } else {
187 fwd_reg = obj_reg;
188 }
189
190 // ------------ obj and fwd are safe at this point --------------
191
192 switch (_options._verify_marked) {
193 case ShenandoahVerifier::_verify_marked_disable:
194 // skip
195 break;
196 case ShenandoahVerifier::_verify_marked_incomplete:
197 verify(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
198 "Must be marked in incomplete bitmap");
199 case ShenandoahVerifier::_verify_marked_complete:
200 verify(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
201 "Must be marked in complete bitmap");
202 break;
203 default:
204 assert(false, "Unhandled mark verification");
205 }
206
207 switch (_options._verify_forwarded) {
208 case ShenandoahVerifier::_verify_forwarded_disable:
209 // skip
210 break;
211 case ShenandoahVerifier::_verify_forwarded_none: {
212 verify(ShenandoahAsserts::_safe_all, obj, obj == fwd,
213 "Should not be forwarded");
214 break;
215 }
216 case ShenandoahVerifier::_verify_forwarded_allow: {
217 if (obj != fwd) {
218 verify(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
219 "Forwardee should be in another region");
220 }
221 break;
222 }
223 default:
224 assert(false, "Unhandled forwarding verification");
225 }
226
227 switch (_options._verify_cset) {
228 case ShenandoahVerifier::_verify_cset_disable:
229 // skip
230 break;
231 case ShenandoahVerifier::_verify_cset_none:
232 verify(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
233 "Should not have references to collection set");
234 break;
235 case ShenandoahVerifier::_verify_cset_forwarded:
236 if (_heap->in_collection_set(obj)) {
237 verify(ShenandoahAsserts::_safe_all, obj, obj != fwd,
238 "Object in collection set, should have forwardee");
239 }
240 break;
241 default:
242 assert(false, "Unhandled cset verification");
243 }
244 }
245
246 public:
247 /**
248 * Verify object with known interior reference.
249 * @param p interior reference where the object is referenced from; can be off-heap
250 * @param obj verified object
251 */
252 template <class T>
253 void verify_oop_at(T* p, oop obj) {
254 _interior_loc = p;
255 verify_oop(obj);
256 _interior_loc = NULL;
257 }
258
259 /**
260 * Verify object without known interior reference.
261 * Useful when picking up the object at known offset in heap,
262 * but without knowing what objects reference it.
263 * @param obj verified object
264 */
265 void verify_oop_standalone(oop obj) {
266 _interior_loc = NULL;
267 verify_oop(obj);
268 _interior_loc = NULL;
269 }
270
271 /**
272 * Verify oop fields from this object.
273 * @param obj host object for verified fields
274 */
275 void verify_oops_from(oop obj) {
276 _loc = obj;
277 obj->oop_iterate(this);
278 _loc = NULL;
279 }
280
281 void do_oop(oop* p) { do_oop_work(p); }
282 void do_oop(narrowOop* p) { do_oop_work(p); }
283 };
284
285 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
286 private:
287 size_t _used, _committed, _garbage;
288 public:
289 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
290
291 void heap_region_do(ShenandoahHeapRegion* r) {
292 _used += r->used();
293 _garbage += r->garbage();
294 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
295 }
296
297 size_t used() { return _used; }
298 size_t committed() { return _committed; }
299 size_t garbage() { return _garbage; }
300 };
301
302 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
303 private:
304 ShenandoahHeap* _heap;
305 const char* _phase;
306 ShenandoahVerifier::VerifyRegions _regions;
307 public:
308 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
309 _heap(ShenandoahHeap::heap()),
310 _phase(phase),
311 _regions(regions) {};
312
313 void print_failure(ShenandoahHeapRegion* r, const char* label) {
314 ResourceMark rm;
315
316 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
317
318 stringStream ss;
319 r->print_on(&ss);
320 msg.append("%s", ss.as_string());
321
322 report_vm_error(__FILE__, __LINE__, msg.buffer());
323 }
324
325 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
326 if (!test) {
327 print_failure(r, msg);
328 }
329 }
330
331 void heap_region_do(ShenandoahHeapRegion* r) {
332 switch (_regions) {
333 case ShenandoahVerifier::_verify_regions_disable:
334 break;
335 case ShenandoahVerifier::_verify_regions_notrash:
336 verify(r, !r->is_trash(),
337 "Should not have trash regions");
338 break;
339 case ShenandoahVerifier::_verify_regions_nocset:
340 verify(r, !r->is_cset(),
341 "Should not have cset regions");
342 break;
343 case ShenandoahVerifier::_verify_regions_notrash_nocset:
344 verify(r, !r->is_trash(),
345 "Should not have trash regions");
346 verify(r, !r->is_cset(),
347 "Should not have cset regions");
348 break;
349 default:
350 ShouldNotReachHere();
351 }
352
353 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
354 "Capacity should match region size");
355
356 verify(r, r->bottom() <= r->top(),
357 "Region top should not be less than bottom");
358
359 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
360 "Region TAMS should not be less than bottom");
361
362 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
363 "Complete TAMS should not be larger than top");
364
365 verify(r, r->get_live_data_bytes() <= r->capacity(),
366 "Live data cannot be larger than capacity");
367
368 verify(r, r->garbage() <= r->capacity(),
369 "Garbage cannot be larger than capacity");
370
371 verify(r, r->used() <= r->capacity(),
372 "Used cannot be larger than capacity");
373
374 verify(r, r->get_shared_allocs() <= r->capacity(),
375 "Shared alloc count should not be larger than capacity");
376
377 verify(r, r->get_tlab_allocs() <= r->capacity(),
378 "TLAB alloc count should not be larger than capacity");
379
380 verify(r, r->get_gclab_allocs() <= r->capacity(),
381 "GCLAB alloc count should not be larger than capacity");
382
383 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
384 "Accurate accounting: shared + TLAB + GCLAB = used");
385
386 verify(r, !r->is_empty() || !r->has_live(),
387 "Empty regions should not have live data");
388
389 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
390 "Transitional: region flags and collection set agree");
391 }
392 };
393
394 class ShenandoahVerifierReachableTask : public AbstractGangTask {
395 private:
396 const char* _label;
397 ShenandoahRootVerifier* _verifier;
398 ShenandoahVerifier::VerifyOptions _options;
399 ShenandoahHeap* _heap;
400 ShenandoahLivenessData* _ld;
401 MarkBitMap* _bitmap;
402 volatile jlong _processed;
403
404 public:
405 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
406 ShenandoahLivenessData* ld,
407 ShenandoahRootVerifier* verifier,
408 const char* label,
409 ShenandoahVerifier::VerifyOptions options) :
410 AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),
411 _label(label),
412 _verifier(verifier),
413 _options(options),
414 _heap(ShenandoahHeap::heap()),
415 _ld(ld),
416 _bitmap(bitmap),
417 _processed(0) {};
418
419 size_t processed() {
420 return (size_t) _processed;
421 }
422
423 virtual void work(uint worker_id) {
424 ResourceMark rm;
425 ShenandoahVerifierStack stack;
426
427 // On level 2, we need to only check the roots once.
428 // On level 3, we want to check the roots, and seed the local stack.
429 // It is a lesser evil to accept multiple root scans at level 3, because
430 // extended parallelism would buy us out.
431 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
432 || (ShenandoahVerifyLevel >= 3)) {
433 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
434 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Roots", _label),
435 _options);
436 if (_heap->unload_classes()) {
437 _verifier->strong_roots_do(&cl);
438 } else {
439 _verifier->roots_do(&cl);
440 }
441 }
442
443 jlong processed = 0;
444
445 if (ShenandoahVerifyLevel >= 3) {
446 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
447 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Reachable", _label),
448 _options);
449 while (!stack.is_empty()) {
450 processed++;
451 ShenandoahVerifierTask task = stack.pop();
452 cl.verify_oops_from(task.obj());
453 }
454 }
455
456 Atomic::add(processed, &_processed);
457 }
458 };
459
460 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
461 private:
462 const char* _label;
463 ShenandoahVerifier::VerifyOptions _options;
464 ShenandoahHeap *_heap;
465 ShenandoahLivenessData* _ld;
466 MarkBitMap* _bitmap;
467 volatile jint _claimed;
468 volatile jlong _processed;
469
470 public:
471 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
472 ShenandoahLivenessData* ld,
473 const char* label,
474 ShenandoahVerifier::VerifyOptions options) :
475 AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),
476 _label(label),
477 _options(options),
478 _heap(ShenandoahHeap::heap()),
479 _bitmap(bitmap),
480 _ld(ld),
481 _claimed(0),
482 _processed(0) {};
483
484 size_t processed() {
485 return (size_t) _processed;
486 }
487
488 virtual void work(uint worker_id) {
489 ShenandoahVerifierStack stack;
490 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
491 ShenandoahMessageBuffer("Shenandoah verification failed; %s, Marked", _label),
492 _options);
493 assert((size_t)max_jint >= _heap->num_regions(), "Too many regions");
494 while (true) {
495 size_t v = (size_t) (Atomic::add(1, &_claimed) - 1);
496 if (v < _heap->num_regions()) {
497 ShenandoahHeapRegion* r = _heap->get_region(v);
498 if (!r->is_humongous() && !r->is_trash()) {
499 work_regular(r, stack, cl);
500 } else if (r->is_humongous_start()) {
501 work_humongous(r, stack, cl);
502 }
503 } else {
504 break;
505 }
506 }
507 }
508
509 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
510 jlong processed = 0;
511 HeapWord* obj = r->bottom();
512 if (_heap->complete_marking_context()->is_marked((oop)obj)) {
513 verify_and_follow(obj, stack, cl, &processed);
514 }
515 Atomic::add(processed, &_processed);
516 }
517
518 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
519 jlong processed = 0;
520 MarkBitMap* mark_bit_map = _heap->complete_marking_context()->mark_bit_map();
521 HeapWord* tams = _heap->complete_marking_context()->top_at_mark_start(r);
522
523 // Bitmaps, before TAMS
524 if (tams > r->bottom()) {
525 HeapWord* start = r->bottom();
526 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, tams);
527
528 while (addr < tams) {
529 verify_and_follow(addr, stack, cl, &processed);
530 addr += 1;
531 if (addr < tams) {
532 addr = mark_bit_map->getNextMarkedWordAddress(addr, tams);
533 }
534 }
535 }
536
537 // Size-based, after TAMS
538 {
539 HeapWord* limit = r->top();
540 HeapWord* addr = tams;
541
542 while (addr < limit) {
543 verify_and_follow(addr, stack, cl, &processed);
544 addr += oop(addr)->size();
545 }
546 }
547
548 Atomic::add(processed, &_processed);
549 }
550
551 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, jlong *processed) {
552 if (!_bitmap->parMark(addr)) return;
553
554 // Verify the object itself:
555 oop obj = oop(addr);
556 cl.verify_oop_standalone(obj);
557
558 // Verify everything reachable from that object too, hopefully realizing
559 // everything was already marked, and never touching further:
560 cl.verify_oops_from(obj);
561 (*processed)++;
562
563 while (!stack.is_empty()) {
564 ShenandoahVerifierTask task = stack.pop();
565 cl.verify_oops_from(task.obj());
566 (*processed)++;
567 }
568 }
569 };
570
571 class VerifyThreadGCState : public ThreadClosure {
572 private:
573 const char* const _label;
574 char const _expected;
575
576 public:
577 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
578 void do_thread(Thread* t) {
579 assert(t->is_Java_thread(), "sanity");
580 char actual = ((JavaThread*)t)->gc_state();
581 if (actual != _expected) {
582 fatal(err_msg("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual));
583 }
584 }
585 };
586
587 class ShenandoahGCStateResetter : public StackObj {
588 private:
589 ShenandoahHeap* const _heap;
590 char _gc_state;
591
592 public:
593 ShenandoahGCStateResetter() : _heap(ShenandoahHeap::heap()) {
594 _gc_state = _heap->gc_state();
595 _heap->_gc_state.clear();
596 }
597
598 ~ShenandoahGCStateResetter() {
599 _heap->_gc_state.set(_gc_state);
600 assert(_heap->gc_state() == _gc_state, "Should be restored");
601 }
602 };
603
604 void ShenandoahVerifier::verify_at_safepoint(const char *label,
605 VerifyForwarded forwarded, VerifyMarked marked,
606 VerifyCollectionSet cset,
607 VerifyLiveness liveness, VerifyRegions regions,
608 VerifyGCState gcstate) {
609 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
610 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
611
612 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
613 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
614
615 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
616
617 // GC state checks
618 {
619 char expected = -1;
620 bool enabled;
621 switch (gcstate) {
622 case _verify_gcstate_disable:
623 enabled = false;
624 break;
625 case _verify_gcstate_forwarded:
626 enabled = true;
627 expected = ShenandoahHeap::HAS_FORWARDED;
628 break;
629 case _verify_gcstate_evacuation:
630 enabled = true;
631 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
632 break;
633 case _verify_gcstate_stable:
634 enabled = true;
635 expected = ShenandoahHeap::STABLE;
636 break;
637 default:
638 enabled = false;
639 assert(false, "Unhandled gc-state verification");
640 }
641
642 if (enabled) {
643 char actual = _heap->gc_state();
644 if (actual != expected) {
645 fatal(err_msg("%s: Global gc-state: expected %d, actual %d", label, expected, actual));
646 }
647
648 VerifyThreadGCState vtgcs(label, expected);
649 Threads::java_threads_do(&vtgcs);
650 }
651 }
652
653 // Deactivate barriers temporarily: Verifier wants plain heap accesses
654 ShenandoahGCStateResetter resetter;
655
656 // Heap size checks
657 {
658 ShenandoahHeapLocker lock(_heap->lock());
659
660 ShenandoahCalculateRegionStatsClosure cl;
661 _heap->heap_region_iterate(&cl);
662 size_t heap_used = _heap->used();
663 guarantee(cl.used() == heap_used,
664 err_msg("%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
665 label,
666 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
667 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used())));
668
669 size_t heap_committed = _heap->committed();
670 guarantee(cl.committed() == heap_committed,
671 err_msg("%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
672 label,
673 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
674 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed())));
675 }
676
677 // Internal heap region checks
678 if (ShenandoahVerifyLevel >= 1) {
679 ShenandoahVerifyHeapRegionClosure cl(label, regions);
680 _heap->heap_region_iterate(&cl);
681 }
682
683 OrderAccess::fence();
684 _heap->make_parsable(false);
685
686 // Allocate temporary bitmap for storing marking wavefront:
687 _verification_bit_map->clear();
688
689 // Allocate temporary array for storing liveness data
690 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
691 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
692
693 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
694
695 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
696 // This verifies what application can see, since it only cares about reachable objects.
697 size_t count_reachable = 0;
698 if (ShenandoahVerifyLevel >= 2) {
699 ShenandoahRootVerifier verifier;
700
701 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, &verifier, label, options);
702 _heap->workers()->run_task(&task);
703 count_reachable = task.processed();
704 }
705
706 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
707 // not the application, can see during the region scans. There is no reason to process the objects
708 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
709 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
710 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
711 // version
712
713 size_t count_marked = 0;
714 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete) {
715 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
716 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
717 _heap->workers()->run_task(&task);
718 count_marked = task.processed();
719 } else {
720 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
721 }
722
723 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
724 // marked objects.
725
726 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
727 for (size_t i = 0; i < _heap->num_regions(); i++) {
728 ShenandoahHeapRegion* r = _heap->get_region(i);
729
730 jint verf_live = 0;
731 if (r->is_humongous()) {
732 // For humongous objects, test if start region is marked live, and if so,
733 // all humongous regions in that chain have live data equal to their "used".
734 jint start_live = OrderAccess::load_acquire(&ld[r->humongous_start_region()->index()]);
735 if (start_live > 0) {
736 verf_live = (jint)(r->used() / HeapWordSize);
737 }
738 } else {
739 verf_live = OrderAccess::load_acquire(&ld[r->index()]);
740 }
741
742 size_t reg_live = r->get_live_data_words();
743 if (reg_live != (size_t)verf_live) {
744 ResourceMark rm;
745 stringStream ss;
746 r->print_on(&ss);
747 fatal(err_msg("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " INT32_FORMAT "\n%s",
748 label, reg_live, verf_live, ss.as_string()));
749 }
750 }
751 }
752
753 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
754 label, ShenandoahVerifyLevel, count_reachable, count_marked);
755
756 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld, mtGC);
757 }
758
759 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
760 verify_at_safepoint(
761 "Generic Verification",
762 _verify_forwarded_allow, // conservatively allow forwarded
763 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
764 _verify_cset_disable, // cset may be inconsistent
765 _verify_liveness_disable, // no reliable liveness data
766 _verify_regions_disable, // no reliable region data
767 _verify_gcstate_disable // no data about gcstate
768 );
769 }
770
771 void ShenandoahVerifier::verify_before_concmark() {
772 verify_at_safepoint(
773 "Before Mark",
774 _verify_forwarded_none, // UR should have fixed up
775 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
776 _verify_cset_none, // UR should have fixed this
777 _verify_liveness_disable, // no reliable liveness data
778 _verify_regions_notrash, // no trash regions
779 _verify_gcstate_stable // there are no forwarded objects
780 );
781 }
782
783 void ShenandoahVerifier::verify_after_concmark() {
784 verify_at_safepoint(
785 "After Mark",
786 _verify_forwarded_none, // no forwarded references
787 _verify_marked_complete, // bitmaps as precise as we can get
788 _verify_cset_none, // no references to cset anymore
789 _verify_liveness_complete, // liveness data must be complete here
790 _verify_regions_disable, // trash regions not yet recycled
791 _verify_gcstate_stable // mark should have stabilized the heap
792 );
793 }
794
795 void ShenandoahVerifier::verify_before_evacuation() {
796 verify_at_safepoint(
797 "Before Evacuation",
798 _verify_forwarded_none, // no forwarded references
799 _verify_marked_complete, // walk over marked objects too
800 _verify_cset_disable, // non-forwarded references to cset expected
801 _verify_liveness_complete, // liveness data must be complete here
802 _verify_regions_disable, // trash regions not yet recycled
803 _verify_gcstate_stable // mark should have stabilized the heap
804 );
805 }
806
807 void ShenandoahVerifier::verify_during_evacuation() {
808 verify_at_safepoint(
809 "During Evacuation",
810 _verify_forwarded_allow, // some forwarded references are allowed
811 _verify_marked_disable, // walk only roots
812 _verify_cset_disable, // some cset references are not forwarded yet
813 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
814 _verify_regions_disable, // trash regions not yet recycled
815 _verify_gcstate_evacuation // evacuation is in progress
816 );
817 }
818
819 void ShenandoahVerifier::verify_after_evacuation() {
820 verify_at_safepoint(
821 "After Evacuation",
822 _verify_forwarded_allow, // objects are still forwarded
823 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
824 _verify_cset_forwarded, // all cset refs are fully forwarded
825 _verify_liveness_disable, // no reliable liveness data anymore
826 _verify_regions_notrash, // trash regions have been recycled already
827 _verify_gcstate_forwarded // evacuation produced some forwarded objects
828 );
829 }
830
831 void ShenandoahVerifier::verify_before_updaterefs() {
832 verify_at_safepoint(
833 "Before Updating References",
834 _verify_forwarded_allow, // forwarded references allowed
835 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
836 _verify_cset_forwarded, // all cset refs are fully forwarded
837 _verify_liveness_disable, // no reliable liveness data anymore
838 _verify_regions_notrash, // trash regions have been recycled already
839 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
840 );
841 }
842
843 void ShenandoahVerifier::verify_after_updaterefs() {
844 verify_at_safepoint(
845 "After Updating References",
846 _verify_forwarded_none, // no forwarded references
847 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
848 _verify_cset_none, // no cset references, all updated
849 _verify_liveness_disable, // no reliable liveness data anymore
850 _verify_regions_nocset, // no cset regions, trash regions have appeared
851 _verify_gcstate_stable // update refs had cleaned up forwarded objects
852 );
853 }
854
855 void ShenandoahVerifier::verify_before_fullgc() {
856 verify_at_safepoint(
857 "Before Full GC",
858 _verify_forwarded_allow, // can have forwarded objects
859 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
860 _verify_cset_disable, // cset might be foobared
861 _verify_liveness_disable, // no reliable liveness data anymore
862 _verify_regions_disable, // no reliable region data here
863 _verify_gcstate_disable // no reliable gcstate data
864 );
865 }
866
867 void ShenandoahVerifier::verify_after_fullgc() {
868 verify_at_safepoint(
869 "After Full GC",
870 _verify_forwarded_none, // all objects are non-forwarded
871 _verify_marked_complete, // all objects are marked in complete bitmap
872 _verify_cset_none, // no cset references
873 _verify_liveness_disable, // no reliable liveness data anymore
874 _verify_regions_notrash_nocset, // no trash, no cset
875 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
876 );
877 }
878 void ShenandoahVerifier::verify_after_degenerated() {
879 verify_at_safepoint(
880 "After Degenerated GC",
881 _verify_forwarded_none, // all objects are non-forwarded
882 _verify_marked_complete, // all objects are marked in complete bitmap
883 _verify_cset_none, // no cset references
884 _verify_liveness_disable, // no reliable liveness data anymore
885 _verify_regions_notrash_nocset, // no trash, no cset
886 _verify_gcstate_stable // full gc cleaned up everything
887 );
888 }
889
890 class ShenandoahVerifyNoForwared : public OopClosure {
891 private:
892 template <class T>
893 void do_oop_work(T* p) {
894 T o = oopDesc::load_heap_oop(p);
895 if (!oopDesc::is_null(o)) {
896 oop obj = oopDesc::decode_heap_oop_not_null(o);
897 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
898 if (obj != fwd) {
899 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
900 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
901 }
902 }
903 }
904
905 public:
906 void do_oop(narrowOop* p) { do_oop_work(p); }
907 void do_oop(oop* p) { do_oop_work(p); }
908 };
909
910 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
911 private:
912 template <class T>
913 void do_oop_work(T* p) {
914 T o = oopDesc::load_heap_oop(p);
915 if (!oopDesc::is_null(o)) {
916 oop obj = oopDesc::decode_heap_oop_not_null(o);
917 ShenandoahHeap* heap = ShenandoahHeap::heap();
918
919 if (!heap->marking_context()->is_marked(obj)) {
920 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
921 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
922 }
923
924 if (heap->in_collection_set(obj)) {
925 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
926 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
927 }
928
929 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
930 if (obj != fwd) {
931 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
932 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
933 }
934 }
935 }
936
937 public:
938 void do_oop(narrowOop* p) { do_oop_work(p); }
939 void do_oop(oop* p) { do_oop_work(p); }
940 };
941
942 void ShenandoahVerifier::verify_roots_in_to_space() {
943 ShenandoahRootVerifier verifier;
944 ShenandoahVerifyInToSpaceClosure cl;
945 verifier.oops_do(&cl);
946 }
947
948 void ShenandoahVerifier::verify_roots_no_forwarded() {
949 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
950 ShenandoahRootVerifier verifier;
951 ShenandoahVerifyNoForwared cl;
952 verifier.oops_do(&cl);
953 }
954
955 void ShenandoahVerifier::verify_roots_no_forwarded_except(ShenandoahRootVerifier::RootTypes types) {
956 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
957 ShenandoahRootVerifier verifier;
958 verifier.excludes(types);
959 ShenandoahVerifyNoForwared cl;
960 verifier.oops_do(&cl);
961 }
962