1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/tlab_globals.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
32 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
33 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "gc/shenandoah/shenandoahVerifier.hpp"
36 #include "memory/allocation.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/compressedOops.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/orderAccess.hpp"
42 #include "runtime/threads.hpp"
43 #include "utilities/align.hpp"
44
45 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
46 #ifdef verify_oop
47 #undef verify_oop
48 #endif
49
50 static bool is_instance_ref_klass(Klass* k) {
51 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
52 }
53
54 class ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
55 public:
56 virtual bool discover_reference(oop obj, ReferenceType type) {
57 return true;
58 }
59 };
60
61 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
62 private:
63 const char* _phase;
64 ShenandoahVerifier::VerifyOptions _options;
65 ShenandoahVerifierStack* _stack;
66 ShenandoahHeap* _heap;
67 MarkBitMap* _map;
68 ShenandoahLivenessData* _ld;
69 void* _interior_loc;
70 oop _loc;
71
72 public:
73 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
74 const char* phase, ShenandoahVerifier::VerifyOptions options) :
75 _phase(phase),
76 _options(options),
77 _stack(stack),
78 _heap(ShenandoahHeap::heap()),
79 _map(map),
80 _ld(ld),
81 _interior_loc(nullptr),
82 _loc(nullptr) {
83 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
84 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
85 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
86 }
87 }
88
89 private:
90 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
91 if (!test) {
92 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
93 }
94 }
95
96 template <class T>
97 void do_oop_work(T* p) {
98 T o = RawAccess<>::oop_load(p);
99 if (!CompressedOops::is_null(o)) {
100 oop obj = CompressedOops::decode_not_null(o);
101 if (is_instance_ref_klass(obj->forward_safe_klass())) {
102 obj = ShenandoahForwarding::get_forwardee(obj);
103 }
104 // Single threaded verification can use faster non-atomic stack and bitmap
105 // methods.
106 //
107 // For performance reasons, only fully verify non-marked field values.
108 // We are here when the host object for *p is already marked.
109
110 if (_map->par_mark(obj)) {
111 verify_oop_at(p, obj);
112 _stack->push(ShenandoahVerifierTask(obj));
113 }
114 }
115 }
116
117 void verify_oop(oop obj) {
118 // Perform consistency checks with gradually decreasing safety level. This guarantees
119 // that failure report would not try to touch something that was not yet verified to be
120 // safe to process.
121
122 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
123 "oop must be in heap");
124 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
125 "oop must be aligned");
126
127 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
128 Klass* obj_klass = obj->forward_safe_klass();
129
130 // Verify that obj is not in dead space:
131 {
132 // Do this before touching obj->size()
133 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
134 "Object klass pointer should not be null");
135 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
136 "Object klass pointer must go to metaspace");
137
138 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
139 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
140 "Object start should be within the region");
141
142 if (!obj_reg->is_humongous()) {
143 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->forward_safe_size()) <= obj_reg->top(),
144 "Object end should be within the region");
145 } else {
146 size_t humongous_start = obj_reg->index();
147 size_t humongous_end = humongous_start + (obj->forward_safe_size() >> ShenandoahHeapRegion::region_size_words_shift());
148 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
149 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
150 "Humongous object is in continuation that fits it");
151 }
152 }
153
154 // ------------ obj is safe at this point --------------
155
156 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
157 "Object should be in active region");
158
159 switch (_options._verify_liveness) {
160 case ShenandoahVerifier::_verify_liveness_disable:
161 // skip
162 break;
163 case ShenandoahVerifier::_verify_liveness_complete:
164 Atomic::add(&_ld[obj_reg->index()], (uint) obj->forward_safe_size(), memory_order_relaxed);
165 // fallthrough for fast failure for un-live regions:
166 case ShenandoahVerifier::_verify_liveness_conservative:
167 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
168 "Object must belong to region with live data");
169 break;
170 default:
171 assert(false, "Unhandled liveness verification");
172 }
173 }
174
175 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
176
177 ShenandoahHeapRegion* fwd_reg = nullptr;
178
179 if (obj != fwd) {
180 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
181 "Forwardee must be in heap");
182 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
183 "Forwardee is set");
184 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
185 "Forwardee must be aligned");
186
187 // Do this before touching fwd->size()
188 Klass* fwd_klass = fwd->klass_or_null();
189 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != nullptr,
190 "Forwardee klass pointer should not be null");
191 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
192 "Forwardee klass pointer must go to metaspace");
193 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
194 "Forwardee klass pointer must go to metaspace");
195
196 fwd_reg = _heap->heap_region_containing(fwd);
197
198 // Verify that forwardee is not in the dead space:
199 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
200 "Should have no humongous forwardees");
201
202 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
203 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
204 "Forwardee start should be within the region");
205 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->forward_safe_size()) <= fwd_reg->top(),
206 "Forwardee end should be within the region");
207
208 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
209 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
210 "Double forwarding");
211 } else {
212 fwd_reg = obj_reg;
213 }
214
215 // ------------ obj and fwd are safe at this point --------------
216
217 switch (_options._verify_marked) {
218 case ShenandoahVerifier::_verify_marked_disable:
219 // skip
220 break;
221 case ShenandoahVerifier::_verify_marked_incomplete:
222 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
223 "Must be marked in incomplete bitmap");
224 break;
225 case ShenandoahVerifier::_verify_marked_complete:
226 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
227 "Must be marked in complete bitmap");
228 break;
229 case ShenandoahVerifier::_verify_marked_complete_except_references:
230 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
231 "Must be marked in complete bitmap, except j.l.r.Reference referents");
232 break;
233 default:
234 assert(false, "Unhandled mark verification");
235 }
236
237 switch (_options._verify_forwarded) {
238 case ShenandoahVerifier::_verify_forwarded_disable:
239 // skip
240 break;
241 case ShenandoahVerifier::_verify_forwarded_none: {
242 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
243 "Should not be forwarded");
244 break;
245 }
246 case ShenandoahVerifier::_verify_forwarded_allow: {
247 if (obj != fwd) {
248 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
249 "Forwardee should be in another region");
250 }
251 break;
252 }
253 default:
254 assert(false, "Unhandled forwarding verification");
255 }
256
257 switch (_options._verify_cset) {
258 case ShenandoahVerifier::_verify_cset_disable:
259 // skip
260 break;
261 case ShenandoahVerifier::_verify_cset_none:
262 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
263 "Should not have references to collection set");
264 break;
265 case ShenandoahVerifier::_verify_cset_forwarded:
266 if (_heap->in_collection_set(obj)) {
267 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
268 "Object in collection set, should have forwardee");
269 }
270 break;
271 default:
272 assert(false, "Unhandled cset verification");
273 }
274
275 }
276
277 public:
278 /**
279 * Verify object with known interior reference.
280 * @param p interior reference where the object is referenced from; can be off-heap
281 * @param obj verified object
282 */
283 template <class T>
284 void verify_oop_at(T* p, oop obj) {
285 _interior_loc = p;
286 verify_oop(obj);
287 _interior_loc = nullptr;
288 }
289
290 /**
291 * Verify object without known interior reference.
292 * Useful when picking up the object at known offset in heap,
293 * but without knowing what objects reference it.
294 * @param obj verified object
295 */
296 void verify_oop_standalone(oop obj) {
297 _interior_loc = nullptr;
298 verify_oop(obj);
299 _interior_loc = nullptr;
300 }
301
302 /**
303 * Verify oop fields from this object.
304 * @param obj host object for verified fields
305 */
306 void verify_oops_from(oop obj) {
307 _loc = obj;
308 Klass* klass = obj->forward_safe_klass();
309 obj->oop_iterate_backwards(this, klass);
310 _loc = nullptr;
311 }
312
313 virtual void do_oop(oop* p) { do_oop_work(p); }
314 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
315 };
316
317 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
318 private:
319 size_t _used, _committed, _garbage;
320 public:
321 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
322
323 void heap_region_do(ShenandoahHeapRegion* r) {
324 _used += r->used();
325 _garbage += r->garbage();
326 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
327 }
328
329 size_t used() { return _used; }
330 size_t committed() { return _committed; }
331 size_t garbage() { return _garbage; }
332 };
333
334 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
335 private:
336 ShenandoahHeap* _heap;
337 const char* _phase;
338 ShenandoahVerifier::VerifyRegions _regions;
339 public:
340 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
341 _heap(ShenandoahHeap::heap()),
342 _phase(phase),
343 _regions(regions) {};
344
345 void print_failure(ShenandoahHeapRegion* r, const char* label) {
346 ResourceMark rm;
347
348 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
349
350 stringStream ss;
351 r->print_on(&ss);
352 msg.append("%s", ss.as_string());
353
354 report_vm_error(__FILE__, __LINE__, msg.buffer());
355 }
356
357 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
358 if (!test) {
359 print_failure(r, msg);
360 }
361 }
362
363 void heap_region_do(ShenandoahHeapRegion* r) {
364 switch (_regions) {
365 case ShenandoahVerifier::_verify_regions_disable:
366 break;
367 case ShenandoahVerifier::_verify_regions_notrash:
368 verify(r, !r->is_trash(),
369 "Should not have trash regions");
370 break;
371 case ShenandoahVerifier::_verify_regions_nocset:
372 verify(r, !r->is_cset(),
373 "Should not have cset regions");
374 break;
375 case ShenandoahVerifier::_verify_regions_notrash_nocset:
376 verify(r, !r->is_trash(),
377 "Should not have trash regions");
378 verify(r, !r->is_cset(),
379 "Should not have cset regions");
380 break;
381 default:
382 ShouldNotReachHere();
383 }
384
385 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
386 "Capacity should match region size");
387
388 verify(r, r->bottom() <= r->top(),
389 "Region top should not be less than bottom");
390
391 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
392 "Region TAMS should not be less than bottom");
393
394 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
395 "Complete TAMS should not be larger than top");
396
397 verify(r, r->get_live_data_bytes() <= r->capacity(),
398 "Live data cannot be larger than capacity");
399
400 verify(r, r->garbage() <= r->capacity(),
401 "Garbage cannot be larger than capacity");
402
403 verify(r, r->used() <= r->capacity(),
404 "Used cannot be larger than capacity");
405
406 verify(r, r->get_shared_allocs() <= r->capacity(),
407 "Shared alloc count should not be larger than capacity");
408
409 verify(r, r->get_tlab_allocs() <= r->capacity(),
410 "TLAB alloc count should not be larger than capacity");
411
412 verify(r, r->get_gclab_allocs() <= r->capacity(),
413 "GCLAB alloc count should not be larger than capacity");
414
415 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
416 "Accurate accounting: shared + TLAB + GCLAB = used");
417
418 verify(r, !r->is_empty() || !r->has_live(),
419 "Empty regions should not have live data");
420
421 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
422 "Transitional: region flags and collection set agree");
423 }
424 };
425
426 class ShenandoahVerifierReachableTask : public WorkerTask {
427 private:
428 const char* _label;
429 ShenandoahVerifier::VerifyOptions _options;
430 ShenandoahHeap* _heap;
431 ShenandoahLivenessData* _ld;
432 MarkBitMap* _bitmap;
433 volatile size_t _processed;
434
435 public:
436 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
437 ShenandoahLivenessData* ld,
438 const char* label,
439 ShenandoahVerifier::VerifyOptions options) :
440 WorkerTask("Shenandoah Verifier Reachable Objects"),
441 _label(label),
442 _options(options),
443 _heap(ShenandoahHeap::heap()),
444 _ld(ld),
445 _bitmap(bitmap),
446 _processed(0) {};
447
448 size_t processed() {
449 return _processed;
450 }
451
452 virtual void work(uint worker_id) {
453 ResourceMark rm;
454 ShenandoahVerifierStack stack;
455
456 // On level 2, we need to only check the roots once.
457 // On level 3, we want to check the roots, and seed the local stack.
458 // It is a lesser evil to accept multiple root scans at level 3, because
459 // extended parallelism would buy us out.
460 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
461 || (ShenandoahVerifyLevel >= 3)) {
462 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
463 ShenandoahMessageBuffer("%s, Roots", _label),
464 _options);
465 if (_heap->unload_classes()) {
466 ShenandoahRootVerifier::strong_roots_do(&cl);
467 } else {
468 ShenandoahRootVerifier::roots_do(&cl);
469 }
470 }
471
472 size_t processed = 0;
473
474 if (ShenandoahVerifyLevel >= 3) {
475 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
476 ShenandoahMessageBuffer("%s, Reachable", _label),
477 _options);
478 while (!stack.is_empty()) {
479 processed++;
480 ShenandoahVerifierTask task = stack.pop();
481 cl.verify_oops_from(task.obj());
482 }
483 }
484
485 Atomic::add(&_processed, processed, memory_order_relaxed);
486 }
487 };
488
489 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
490 private:
491 const char* _label;
492 ShenandoahVerifier::VerifyOptions _options;
493 ShenandoahHeap *_heap;
494 MarkBitMap* _bitmap;
495 ShenandoahLivenessData* _ld;
496 volatile size_t _claimed;
497 volatile size_t _processed;
498
499 public:
500 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
501 ShenandoahLivenessData* ld,
502 const char* label,
503 ShenandoahVerifier::VerifyOptions options) :
504 WorkerTask("Shenandoah Verifier Marked Objects"),
505 _label(label),
506 _options(options),
507 _heap(ShenandoahHeap::heap()),
508 _bitmap(bitmap),
509 _ld(ld),
510 _claimed(0),
511 _processed(0) {};
512
513 size_t processed() {
514 return Atomic::load(&_processed);
515 }
516
517 virtual void work(uint worker_id) {
518 ShenandoahVerifierStack stack;
519 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
520 ShenandoahMessageBuffer("%s, Marked", _label),
521 _options);
522
523 while (true) {
524 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
525 if (v < _heap->num_regions()) {
526 ShenandoahHeapRegion* r = _heap->get_region(v);
527 if (!r->is_humongous() && !r->is_trash()) {
528 work_regular(r, stack, cl);
529 } else if (r->is_humongous_start()) {
530 work_humongous(r, stack, cl);
531 }
532 } else {
533 break;
534 }
535 }
536 }
537
538 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
539 size_t processed = 0;
540 HeapWord* obj = r->bottom();
541 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
542 verify_and_follow(obj, stack, cl, &processed);
543 }
544 Atomic::add(&_processed, processed, memory_order_relaxed);
545 }
546
547 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
548 size_t processed = 0;
549 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
550 HeapWord* tams = ctx->top_at_mark_start(r);
551
552 // Bitmaps, before TAMS
553 if (tams > r->bottom()) {
554 HeapWord* start = r->bottom();
555 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
556
557 while (addr < tams) {
558 verify_and_follow(addr, stack, cl, &processed);
559 addr += 1;
560 if (addr < tams) {
561 addr = ctx->get_next_marked_addr(addr, tams);
562 }
563 }
564 }
565
566 // Size-based, after TAMS
567 {
568 HeapWord* limit = r->top();
569 HeapWord* addr = tams;
570
571 while (addr < limit) {
572 verify_and_follow(addr, stack, cl, &processed);
573 addr += cast_to_oop(addr)->size();
574 }
575 }
576
577 Atomic::add(&_processed, processed, memory_order_relaxed);
578 }
579
580 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
581 if (!_bitmap->par_mark(addr)) return;
582
583 // Verify the object itself:
584 oop obj = cast_to_oop(addr);
585 cl.verify_oop_standalone(obj);
586
587 // Verify everything reachable from that object too, hopefully realizing
588 // everything was already marked, and never touching further:
589 if (!is_instance_ref_klass(obj->forward_safe_klass())) {
590 cl.verify_oops_from(obj);
591 (*processed)++;
592 }
593 while (!stack.is_empty()) {
594 ShenandoahVerifierTask task = stack.pop();
595 cl.verify_oops_from(task.obj());
596 (*processed)++;
597 }
598 }
599 };
600
601 class VerifyThreadGCState : public ThreadClosure {
602 private:
603 const char* const _label;
604 char const _expected;
605
606 public:
607 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
608 void do_thread(Thread* t) {
609 char actual = ShenandoahThreadLocalData::gc_state(t);
610 if (actual != _expected) {
611 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
612 }
613 }
614 };
615
616 void ShenandoahVerifier::verify_at_safepoint(const char *label,
617 VerifyForwarded forwarded, VerifyMarked marked,
618 VerifyCollectionSet cset,
619 VerifyLiveness liveness, VerifyRegions regions,
620 VerifyGCState gcstate) {
621 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
622 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
623
624 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
625
626 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
627 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
628
629 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
630
631 // GC state checks
632 {
633 char expected = -1;
634 bool enabled;
635 switch (gcstate) {
636 case _verify_gcstate_disable:
637 enabled = false;
638 break;
639 case _verify_gcstate_forwarded:
640 enabled = true;
641 expected = ShenandoahHeap::HAS_FORWARDED;
642 break;
643 case _verify_gcstate_evacuation:
644 enabled = true;
645 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
646 if (!_heap->is_stw_gc_in_progress()) {
647 // Only concurrent GC sets this.
648 expected |= ShenandoahHeap::WEAK_ROOTS;
649 }
650 break;
651 case _verify_gcstate_stable:
652 enabled = true;
653 expected = ShenandoahHeap::STABLE;
654 break;
655 case _verify_gcstate_stable_weakroots:
656 enabled = true;
657 expected = ShenandoahHeap::STABLE;
658 if (!_heap->is_stw_gc_in_progress()) {
659 // Only concurrent GC sets this.
660 expected |= ShenandoahHeap::WEAK_ROOTS;
661 }
662 break;
663 default:
664 enabled = false;
665 assert(false, "Unhandled gc-state verification");
666 }
667
668 if (enabled) {
669 char actual = _heap->gc_state();
670 if (actual != expected) {
671 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
672 }
673
674 VerifyThreadGCState vtgcs(label, expected);
675 Threads::java_threads_do(&vtgcs);
676 }
677 }
678
679 // Deactivate barriers temporarily: Verifier wants plain heap accesses
680 ShenandoahGCStateResetter resetter;
681
682 // Heap size checks
683 {
684 ShenandoahHeapLocker lock(_heap->lock());
685
686 ShenandoahCalculateRegionStatsClosure cl;
687 _heap->heap_region_iterate(&cl);
688 size_t heap_used = _heap->used();
689 guarantee(cl.used() == heap_used,
690 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
691 label,
692 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
693 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
694
695 size_t heap_committed = _heap->committed();
696 guarantee(cl.committed() == heap_committed,
697 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
698 label,
699 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
700 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
701 }
702
703 // Internal heap region checks
704 if (ShenandoahVerifyLevel >= 1) {
705 ShenandoahVerifyHeapRegionClosure cl(label, regions);
706 _heap->heap_region_iterate(&cl);
707 }
708
709 OrderAccess::fence();
710
711 if (UseTLAB) {
712 _heap->labs_make_parsable();
713 }
714
715 // Allocate temporary bitmap for storing marking wavefront:
716 _verification_bit_map->clear();
717
718 // Allocate temporary array for storing liveness data
719 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
720 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
721
722 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
723
724 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
725 // This verifies what application can see, since it only cares about reachable objects.
726 size_t count_reachable = 0;
727 if (ShenandoahVerifyLevel >= 2) {
728 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
729 _heap->workers()->run_task(&task);
730 count_reachable = task.processed();
731 }
732
733 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
734 // not the application, can see during the region scans. There is no reason to process the objects
735 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
736 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
737 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
738 // version
739
740 size_t count_marked = 0;
741 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
742 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
743 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
744 _heap->workers()->run_task(&task);
745 count_marked = task.processed();
746 } else {
747 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
748 }
749
750 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
751 // marked objects.
752
753 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
754 for (size_t i = 0; i < _heap->num_regions(); i++) {
755 ShenandoahHeapRegion* r = _heap->get_region(i);
756
757 juint verf_live = 0;
758 if (r->is_humongous()) {
759 // For humongous objects, test if start region is marked live, and if so,
760 // all humongous regions in that chain have live data equal to their "used".
761 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
762 if (start_live > 0) {
763 verf_live = (juint)(r->used() / HeapWordSize);
764 }
765 } else {
766 verf_live = Atomic::load(&ld[r->index()]);
767 }
768
769 size_t reg_live = r->get_live_data_words();
770 if (reg_live != verf_live) {
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.freeze());
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, nullptr,
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, nullptr,
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, nullptr,
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, nullptr,
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 }