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->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->klass_or_null();
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->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->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->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->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 obj->oop_iterate(this);
308 _loc = NULL;
309 }
310
311 virtual void do_oop(oop* p) { do_oop_work(p); }
312 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
313 };
314
315 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
316 private:
317 size_t _used, _committed, _garbage;
318 public:
319 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
320
321 void heap_region_do(ShenandoahHeapRegion* r) {
322 _used += r->used();
323 _garbage += r->garbage();
324 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
325 }
326
327 size_t used() { return _used; }
328 size_t committed() { return _committed; }
329 size_t garbage() { return _garbage; }
330 };
331
332 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
333 private:
334 ShenandoahHeap* _heap;
335 const char* _phase;
336 ShenandoahVerifier::VerifyRegions _regions;
337 public:
338 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
339 _heap(ShenandoahHeap::heap()),
340 _phase(phase),
341 _regions(regions) {};
342
343 void print_failure(ShenandoahHeapRegion* r, const char* label) {
344 ResourceMark rm;
345
346 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
347
348 stringStream ss;
349 r->print_on(&ss);
350 msg.append("%s", ss.as_string());
351
352 report_vm_error(__FILE__, __LINE__, msg.buffer());
353 }
354
355 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
356 if (!test) {
357 print_failure(r, msg);
358 }
359 }
360
361 void heap_region_do(ShenandoahHeapRegion* r) {
362 switch (_regions) {
363 case ShenandoahVerifier::_verify_regions_disable:
364 break;
365 case ShenandoahVerifier::_verify_regions_notrash:
366 verify(r, !r->is_trash(),
367 "Should not have trash regions");
368 break;
369 case ShenandoahVerifier::_verify_regions_nocset:
370 verify(r, !r->is_cset(),
371 "Should not have cset regions");
372 break;
373 case ShenandoahVerifier::_verify_regions_notrash_nocset:
374 verify(r, !r->is_trash(),
375 "Should not have trash regions");
376 verify(r, !r->is_cset(),
377 "Should not have cset regions");
378 break;
379 default:
380 ShouldNotReachHere();
381 }
382
383 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
384 "Capacity should match region size");
385
386 verify(r, r->bottom() <= r->top(),
387 "Region top should not be less than bottom");
388
389 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
390 "Region TAMS should not be less than bottom");
391
392 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
393 "Complete TAMS should not be larger than top");
394
395 verify(r, r->get_live_data_bytes() <= r->capacity(),
396 "Live data cannot be larger than capacity");
397
398 verify(r, r->garbage() <= r->capacity(),
399 "Garbage cannot be larger than capacity");
400
401 verify(r, r->used() <= r->capacity(),
402 "Used cannot be larger than capacity");
403
404 verify(r, r->get_shared_allocs() <= r->capacity(),
405 "Shared alloc count should not be larger than capacity");
406
407 verify(r, r->get_tlab_allocs() <= r->capacity(),
408 "TLAB alloc count should not be larger than capacity");
409
410 verify(r, r->get_gclab_allocs() <= r->capacity(),
411 "GCLAB alloc count should not be larger than capacity");
412
413 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
414 "Accurate accounting: shared + TLAB + GCLAB = used");
415
416 verify(r, !r->is_empty() || !r->has_live(),
417 "Empty regions should not have live data");
418
419 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
420 "Transitional: region flags and collection set agree");
421 }
422 };
423
424 class ShenandoahVerifierReachableTask : public AbstractGangTask {
425 private:
426 const char* _label;
427 ShenandoahVerifier::VerifyOptions _options;
428 ShenandoahHeap* _heap;
429 ShenandoahLivenessData* _ld;
430 MarkBitMap* _bitmap;
431 volatile size_t _processed;
432
433 public:
434 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
435 ShenandoahLivenessData* ld,
436 const char* label,
437 ShenandoahVerifier::VerifyOptions options) :
438 AbstractGangTask("Shenandoah Verifier Reachable Objects"),
439 _label(label),
440 _options(options),
441 _heap(ShenandoahHeap::heap()),
442 _ld(ld),
443 _bitmap(bitmap),
444 _processed(0) {};
445
446 size_t processed() {
447 return _processed;
448 }
449
450 virtual void work(uint worker_id) {
451 ResourceMark rm;
452 ShenandoahVerifierStack stack;
453
454 // On level 2, we need to only check the roots once.
455 // On level 3, we want to check the roots, and seed the local stack.
456 // It is a lesser evil to accept multiple root scans at level 3, because
457 // extended parallelism would buy us out.
458 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
459 || (ShenandoahVerifyLevel >= 3)) {
460 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
461 ShenandoahMessageBuffer("%s, Roots", _label),
462 _options);
463 if (_heap->unload_classes()) {
464 ShenandoahRootVerifier::strong_roots_do(&cl);
465 } else {
466 ShenandoahRootVerifier::roots_do(&cl);
467 }
468 }
469
470 size_t processed = 0;
471
472 if (ShenandoahVerifyLevel >= 3) {
473 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
474 ShenandoahMessageBuffer("%s, Reachable", _label),
475 _options);
476 while (!stack.is_empty()) {
477 processed++;
478 ShenandoahVerifierTask task = stack.pop();
479 cl.verify_oops_from(task.obj());
480 }
481 }
482
483 Atomic::add(&_processed, processed, memory_order_relaxed);
484 }
485 };
486
487 class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {
488 private:
489 const char* _label;
490 ShenandoahVerifier::VerifyOptions _options;
491 ShenandoahHeap *_heap;
492 MarkBitMap* _bitmap;
493 ShenandoahLivenessData* _ld;
494 volatile size_t _claimed;
495 volatile size_t _processed;
496
497 public:
498 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
499 ShenandoahLivenessData* ld,
500 const char* label,
501 ShenandoahVerifier::VerifyOptions options) :
502 AbstractGangTask("Shenandoah Verifier Marked Objects"),
503 _label(label),
504 _options(options),
505 _heap(ShenandoahHeap::heap()),
506 _bitmap(bitmap),
507 _ld(ld),
508 _claimed(0),
509 _processed(0) {};
510
511 size_t processed() {
512 return Atomic::load(&_processed);
513 }
514
515 virtual void work(uint worker_id) {
516 ShenandoahVerifierStack stack;
517 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
518 ShenandoahMessageBuffer("%s, Marked", _label),
519 _options);
520
521 while (true) {
522 size_t v = Atomic::fetch_and_add(&_claimed, 1u, memory_order_relaxed);
523 if (v < _heap->num_regions()) {
524 ShenandoahHeapRegion* r = _heap->get_region(v);
525 if (!r->is_humongous() && !r->is_trash()) {
526 work_regular(r, stack, cl);
527 } else if (r->is_humongous_start()) {
528 work_humongous(r, stack, cl);
529 }
530 } else {
531 break;
532 }
533 }
534 }
535
536 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
537 size_t processed = 0;
538 HeapWord* obj = r->bottom();
539 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
540 verify_and_follow(obj, stack, cl, &processed);
541 }
542 Atomic::add(&_processed, processed, memory_order_relaxed);
543 }
544
545 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
546 size_t processed = 0;
547 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
548 HeapWord* tams = ctx->top_at_mark_start(r);
549
550 // Bitmaps, before TAMS
551 if (tams > r->bottom()) {
552 HeapWord* start = r->bottom();
553 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
554
555 while (addr < tams) {
556 verify_and_follow(addr, stack, cl, &processed);
557 addr += 1;
558 if (addr < tams) {
559 addr = ctx->get_next_marked_addr(addr, tams);
560 }
561 }
562 }
563
564 // Size-based, after TAMS
565 {
566 HeapWord* limit = r->top();
567 HeapWord* addr = tams;
568
569 while (addr < limit) {
570 verify_and_follow(addr, stack, cl, &processed);
571 addr += cast_to_oop(addr)->size();
572 }
573 }
574
575 Atomic::add(&_processed, processed, memory_order_relaxed);
576 }
577
578 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
579 if (!_bitmap->par_mark(addr)) return;
580
581 // Verify the object itself:
582 oop obj = cast_to_oop(addr);
583 cl.verify_oop_standalone(obj);
584
585 // Verify everything reachable from that object too, hopefully realizing
586 // everything was already marked, and never touching further:
587 if (!is_instance_ref_klass(obj->klass())) {
588 cl.verify_oops_from(obj);
589 (*processed)++;
590 }
591 while (!stack.is_empty()) {
592 ShenandoahVerifierTask task = stack.pop();
593 cl.verify_oops_from(task.obj());
594 (*processed)++;
595 }
596 }
597 };
598
599 class VerifyThreadGCState : public ThreadClosure {
600 private:
601 const char* const _label;
602 char const _expected;
603
604 public:
605 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
606 void do_thread(Thread* t) {
607 char actual = ShenandoahThreadLocalData::gc_state(t);
608 if (actual != _expected) {
609 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
610 }
611 }
612 };
613
614 void ShenandoahVerifier::verify_at_safepoint(const char *label,
615 VerifyForwarded forwarded, VerifyMarked marked,
616 VerifyCollectionSet cset,
617 VerifyLiveness liveness, VerifyRegions regions,
618 VerifyGCState gcstate) {
619 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
620 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
621
622 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
623 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
624
625 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
626
627 // GC state checks
628 {
629 char expected = -1;
630 bool enabled;
631 switch (gcstate) {
632 case _verify_gcstate_disable:
633 enabled = false;
634 break;
635 case _verify_gcstate_forwarded:
636 enabled = true;
637 expected = ShenandoahHeap::HAS_FORWARDED;
638 break;
639 case _verify_gcstate_evacuation:
640 enabled = true;
641 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
642 if (!_heap->is_stw_gc_in_progress()) {
643 // Only concurrent GC sets this.
644 expected |= ShenandoahHeap::WEAK_ROOTS;
645 }
646 break;
647 case _verify_gcstate_stable:
648 enabled = true;
649 expected = ShenandoahHeap::STABLE;
650 break;
651 case _verify_gcstate_stable_weakroots:
652 enabled = true;
653 expected = ShenandoahHeap::STABLE;
654 if (!_heap->is_stw_gc_in_progress()) {
655 // Only concurrent GC sets this.
656 expected |= ShenandoahHeap::WEAK_ROOTS;
657 }
658 break;
659 default:
660 enabled = false;
661 assert(false, "Unhandled gc-state verification");
662 }
663
664 if (enabled) {
665 char actual = _heap->gc_state();
666 if (actual != expected) {
667 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
668 }
669
670 VerifyThreadGCState vtgcs(label, expected);
671 Threads::java_threads_do(&vtgcs);
672 }
673 }
674
675 // Deactivate barriers temporarily: Verifier wants plain heap accesses
676 ShenandoahGCStateResetter resetter;
677
678 // Heap size checks
679 {
680 ShenandoahHeapLocker lock(_heap->lock());
681
682 ShenandoahCalculateRegionStatsClosure cl;
683 _heap->heap_region_iterate(&cl);
684 size_t heap_used = _heap->used();
685 guarantee(cl.used() == heap_used,
686 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
687 label,
688 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
689 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
690
691 size_t heap_committed = _heap->committed();
692 guarantee(cl.committed() == heap_committed,
693 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
694 label,
695 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
696 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
697 }
698
699 // Internal heap region checks
700 if (ShenandoahVerifyLevel >= 1) {
701 ShenandoahVerifyHeapRegionClosure cl(label, regions);
702 _heap->heap_region_iterate(&cl);
703 }
704
705 OrderAccess::fence();
706
707 if (UseTLAB) {
708 _heap->labs_make_parsable();
709 }
710
711 // Allocate temporary bitmap for storing marking wavefront:
712 _verification_bit_map->clear();
713
714 // Allocate temporary array for storing liveness data
715 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
716 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
717
718 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
719
720 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
721 // This verifies what application can see, since it only cares about reachable objects.
722 size_t count_reachable = 0;
723 if (ShenandoahVerifyLevel >= 2) {
724 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
725 _heap->workers()->run_task(&task);
726 count_reachable = task.processed();
727 }
728
729 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
730 // not the application, can see during the region scans. There is no reason to process the objects
731 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
732 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
733 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
734 // version
735
736 size_t count_marked = 0;
737 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
738 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
739 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
740 _heap->workers()->run_task(&task);
741 count_marked = task.processed();
742 } else {
743 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
744 }
745
746 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
747 // marked objects.
748
749 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
750 for (size_t i = 0; i < _heap->num_regions(); i++) {
751 ShenandoahHeapRegion* r = _heap->get_region(i);
752
753 juint verf_live = 0;
754 if (r->is_humongous()) {
755 // For humongous objects, test if start region is marked live, and if so,
756 // all humongous regions in that chain have live data equal to their "used".
757 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
758 if (start_live > 0) {
759 verf_live = (juint)(r->used() / HeapWordSize);
760 }
761 } else {
762 verf_live = Atomic::load(&ld[r->index()]);
763 }
764
765 size_t reg_live = r->get_live_data_words();
766 if (reg_live != verf_live) {
767 ResourceMark rm;
768 stringStream ss;
769 r->print_on(&ss);
770 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
771 label, reg_live, verf_live, ss.as_string());
772 }
773 }
774 }
775
776 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
777 label, ShenandoahVerifyLevel, count_reachable, count_marked);
778
779 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
780 }
781
782 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
783 verify_at_safepoint(
784 "Generic Verification",
785 _verify_forwarded_allow, // conservatively allow forwarded
786 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
787 _verify_cset_disable, // cset may be inconsistent
788 _verify_liveness_disable, // no reliable liveness data
789 _verify_regions_disable, // no reliable region data
790 _verify_gcstate_disable // no data about gcstate
791 );
792 }
793
794 void ShenandoahVerifier::verify_before_concmark() {
795 verify_at_safepoint(
796 "Before Mark",
797 _verify_forwarded_none, // UR should have fixed up
798 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
799 _verify_cset_none, // UR should have fixed this
800 _verify_liveness_disable, // no reliable liveness data
801 _verify_regions_notrash, // no trash regions
802 _verify_gcstate_stable // there are no forwarded objects
803 );
804 }
805
806 void ShenandoahVerifier::verify_after_concmark() {
807 verify_at_safepoint(
808 "After Mark",
809 _verify_forwarded_none, // no forwarded references
810 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
811 _verify_cset_none, // no references to cset anymore
812 _verify_liveness_complete, // liveness data must be complete here
813 _verify_regions_disable, // trash regions not yet recycled
814 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
815 );
816 }
817
818 void ShenandoahVerifier::verify_before_evacuation() {
819 verify_at_safepoint(
820 "Before Evacuation",
821 _verify_forwarded_none, // no forwarded references
822 _verify_marked_complete_except_references, // walk over marked objects too
823 _verify_cset_disable, // non-forwarded references to cset expected
824 _verify_liveness_complete, // liveness data must be complete here
825 _verify_regions_disable, // trash regions not yet recycled
826 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
827 );
828 }
829
830 void ShenandoahVerifier::verify_during_evacuation() {
831 verify_at_safepoint(
832 "During Evacuation",
833 _verify_forwarded_allow, // some forwarded references are allowed
834 _verify_marked_disable, // walk only roots
835 _verify_cset_disable, // some cset references are not forwarded yet
836 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
837 _verify_regions_disable, // trash regions not yet recycled
838 _verify_gcstate_evacuation // evacuation is in progress
839 );
840 }
841
842 void ShenandoahVerifier::verify_after_evacuation() {
843 verify_at_safepoint(
844 "After Evacuation",
845 _verify_forwarded_allow, // objects are still forwarded
846 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
847 _verify_cset_forwarded, // all cset refs are fully forwarded
848 _verify_liveness_disable, // no reliable liveness data anymore
849 _verify_regions_notrash, // trash regions have been recycled already
850 _verify_gcstate_forwarded // evacuation produced some forwarded objects
851 );
852 }
853
854 void ShenandoahVerifier::verify_before_updaterefs() {
855 verify_at_safepoint(
856 "Before Updating References",
857 _verify_forwarded_allow, // forwarded references allowed
858 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
859 _verify_cset_forwarded, // all cset refs are fully forwarded
860 _verify_liveness_disable, // no reliable liveness data anymore
861 _verify_regions_notrash, // trash regions have been recycled already
862 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
863 );
864 }
865
866 void ShenandoahVerifier::verify_after_updaterefs() {
867 verify_at_safepoint(
868 "After Updating References",
869 _verify_forwarded_none, // no forwarded references
870 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
871 _verify_cset_none, // no cset references, all updated
872 _verify_liveness_disable, // no reliable liveness data anymore
873 _verify_regions_nocset, // no cset regions, trash regions have appeared
874 _verify_gcstate_stable // update refs had cleaned up forwarded objects
875 );
876 }
877
878 void ShenandoahVerifier::verify_after_degenerated() {
879 verify_at_safepoint(
880 "After Degenerated GC",
881 _verify_forwarded_none, // all objects are non-forwarded
882 _verify_marked_complete, // all objects are marked in complete bitmap
883 _verify_cset_none, // no cset references
884 _verify_liveness_disable, // no reliable liveness data anymore
885 _verify_regions_notrash_nocset, // no trash, no cset
886 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
887 );
888 }
889
890 void ShenandoahVerifier::verify_before_fullgc() {
891 verify_at_safepoint(
892 "Before Full GC",
893 _verify_forwarded_allow, // can have forwarded objects
894 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
895 _verify_cset_disable, // cset might be foobared
896 _verify_liveness_disable, // no reliable liveness data anymore
897 _verify_regions_disable, // no reliable region data here
898 _verify_gcstate_disable // no reliable gcstate data
899 );
900 }
901
902 void ShenandoahVerifier::verify_after_fullgc() {
903 verify_at_safepoint(
904 "After Full GC",
905 _verify_forwarded_none, // all objects are non-forwarded
906 _verify_marked_complete, // all objects are marked in complete bitmap
907 _verify_cset_none, // no cset references
908 _verify_liveness_disable, // no reliable liveness data anymore
909 _verify_regions_notrash_nocset, // no trash, no cset
910 _verify_gcstate_stable // full gc cleaned up everything
911 );
912 }
913
914 class ShenandoahVerifyNoForwared : public OopClosure {
915 private:
916 template <class T>
917 void do_oop_work(T* p) {
918 T o = RawAccess<>::oop_load(p);
919 if (!CompressedOops::is_null(o)) {
920 oop obj = CompressedOops::decode_not_null(o);
921 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
922 if (obj != fwd) {
923 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
924 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
925 }
926 }
927 }
928
929 public:
930 void do_oop(narrowOop* p) { do_oop_work(p); }
931 void do_oop(oop* p) { do_oop_work(p); }
932 };
933
934 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
935 private:
936 template <class T>
937 void do_oop_work(T* p) {
938 T o = RawAccess<>::oop_load(p);
939 if (!CompressedOops::is_null(o)) {
940 oop obj = CompressedOops::decode_not_null(o);
941 ShenandoahHeap* heap = ShenandoahHeap::heap();
942
943 if (!heap->marking_context()->is_marked(obj)) {
944 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
945 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
946 }
947
948 if (heap->in_collection_set(obj)) {
949 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
950 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
951 }
952
953 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
954 if (obj != fwd) {
955 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, NULL,
956 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
957 }
958 }
959 }
960
961 public:
962 void do_oop(narrowOop* p) { do_oop_work(p); }
963 void do_oop(oop* p) { do_oop_work(p); }
964 };
965
966 void ShenandoahVerifier::verify_roots_in_to_space() {
967 ShenandoahVerifyInToSpaceClosure cl;
968 ShenandoahRootVerifier::roots_do(&cl);
969 }
970
971 void ShenandoahVerifier::verify_roots_no_forwarded() {
972 ShenandoahVerifyNoForwared cl;
973 ShenandoahRootVerifier::roots_do(&cl);
974 }