1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/shared/tlab_globals.hpp"
27 #include "gc/shenandoah/shenandoahAsserts.hpp"
28 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
30 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
32 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
33 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
34 #include "gc/shenandoah/shenandoahUtils.hpp"
35 #include "gc/shenandoah/shenandoahVerifier.hpp"
36 #include "memory/allocation.hpp"
37 #include "memory/iterator.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "oops/compressedOops.inline.hpp"
40 #include "runtime/atomic.hpp"
41 #include "runtime/orderAccess.hpp"
42 #include "runtime/threads.hpp"
43 #include "utilities/align.hpp"
44
45 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
46 #ifdef verify_oop
47 #undef verify_oop
48 #endif
49
50 static bool is_instance_ref_klass(Klass* k) {
51 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
52 }
53
54 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
55 private:
56 const char* _phase;
57 ShenandoahVerifier::VerifyOptions _options;
58 ShenandoahVerifierStack* _stack;
59 ShenandoahHeap* _heap;
60 MarkBitMap* _map;
61 ShenandoahLivenessData* _ld;
62 void* _interior_loc;
63 oop _loc;
64 ReferenceIterationMode _ref_mode;
65
66 public:
67 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
68 const char* phase, ShenandoahVerifier::VerifyOptions options) :
69 _phase(phase),
70 _options(options),
71 _stack(stack),
72 _heap(ShenandoahHeap::heap()),
73 _map(map),
74 _ld(ld),
75 _interior_loc(nullptr),
76 _loc(nullptr) {
77 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
78 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
79 // Unknown status for Reference.referent field. Do not touch it, it might be dead.
80 // Normally, barriers would prevent us from seeing the dead referents, but verifier
81 // runs with barriers disabled.
82 _ref_mode = DO_FIELDS_EXCEPT_REFERENT;
83 } else {
84 // Otherwise do all fields.
85 _ref_mode = DO_FIELDS;
86 }
87 }
88
89 ReferenceIterationMode reference_iteration_mode() override {
90 return _ref_mode;
91 }
92
93 private:
94 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
95 if (!test) {
96 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
97 }
98 }
99
100 template <class T>
101 void do_oop_work(T* p) {
102 T o = RawAccess<>::oop_load(p);
103 if (!CompressedOops::is_null(o)) {
104 oop obj = CompressedOops::decode_not_null(o);
105 if (is_instance_ref_klass(obj->klass())) {
106 obj = ShenandoahForwarding::get_forwardee(obj);
107 }
108 // Single threaded verification can use faster non-atomic stack and bitmap
109 // methods.
110 //
111 // For performance reasons, only fully verify non-marked field values.
112 // We are here when the host object for *p is already marked.
113
114 if (_map->par_mark(obj)) {
115 verify_oop_at(p, obj);
116 _stack->push(ShenandoahVerifierTask(obj));
117 }
118 }
119 }
120
121 void verify_oop(oop obj) {
122 // Perform consistency checks with gradually decreasing safety level. This guarantees
123 // that failure report would not try to touch something that was not yet verified to be
124 // safe to process.
125
126 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in_reserved(obj),
127 "oop must be in heap bounds");
128 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
129 "oop must be aligned");
130
131 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
132 Klass* obj_klass = obj->klass_or_null();
133
134 // Verify that obj is not in dead space:
135 {
136 // Do this before touching obj->size()
137 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
138 "Object klass pointer should not be null");
139 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
140 "Object klass pointer must go to metaspace");
141
142 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
143 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
144 "Object start should be within the region");
145
146 if (!obj_reg->is_humongous()) {
147 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
148 "Object end should be within the region");
149 } else {
150 size_t humongous_start = obj_reg->index();
151 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
152 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
153 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
154 "Humongous object is in continuation that fits it");
155 }
156 }
157
158 // ------------ obj is safe at this point --------------
159
160 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
161 "Object should be in active region");
162
163 switch (_options._verify_liveness) {
164 case ShenandoahVerifier::_verify_liveness_disable:
165 // skip
166 break;
167 case ShenandoahVerifier::_verify_liveness_complete:
168 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
169 // fallthrough for fast failure for un-live regions:
170 case ShenandoahVerifier::_verify_liveness_conservative:
171 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
172 "Object must belong to region with live data");
173 break;
174 default:
175 assert(false, "Unhandled liveness verification");
176 }
177 }
178
179 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
180
181 ShenandoahHeapRegion* fwd_reg = nullptr;
182
183 if (obj != fwd) {
184 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in_reserved(fwd),
185 "Forwardee must be in heap bounds");
186 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
187 "Forwardee is set");
188 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
189 "Forwardee must be aligned");
190
191 // Do this before touching fwd->size()
192 Klass* fwd_klass = fwd->klass_or_null();
193 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != nullptr,
194 "Forwardee klass pointer should not be null");
195 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
196 "Forwardee klass pointer must go to metaspace");
197 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
198 "Forwardee klass pointer must go to metaspace");
199
200 fwd_reg = _heap->heap_region_containing(fwd);
201
202 check(ShenandoahAsserts::_safe_oop, obj, fwd_reg->is_active(),
203 "Forwardee should be in active region");
204
205 // Verify that forwardee is not in the dead space:
206 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
207 "Should have no humongous forwardees");
208
209 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
210 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
211 "Forwardee start should be within the region");
212 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
213 "Forwardee end should be within the region");
214
215 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
216 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
217 "Double forwarding");
218 } else {
219 fwd_reg = obj_reg;
220 }
221
222 // Do additional checks for special objects: their fields can hold metadata as well.
223 // We want to check class loading/unloading did not corrupt them.
224
225 if (obj_klass == vmClasses::Class_klass()) {
226 Metadata* klass = obj->metadata_field(java_lang_Class::klass_offset());
227 check(ShenandoahAsserts::_safe_oop, obj,
228 klass == nullptr || Metaspace::contains(klass),
229 "Instance class mirror should point to Metaspace");
230
231 Metadata* array_klass = obj->metadata_field(java_lang_Class::array_klass_offset());
232 check(ShenandoahAsserts::_safe_oop, obj,
233 array_klass == nullptr || Metaspace::contains(array_klass),
234 "Array class mirror should point to Metaspace");
235 }
236
237 // ------------ obj and fwd are safe at this point --------------
238
239 switch (_options._verify_marked) {
240 case ShenandoahVerifier::_verify_marked_disable:
241 // skip
242 break;
243 case ShenandoahVerifier::_verify_marked_incomplete:
244 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
245 "Must be marked in incomplete bitmap");
246 break;
247 case ShenandoahVerifier::_verify_marked_complete:
248 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
249 "Must be marked in complete bitmap");
250 break;
251 case ShenandoahVerifier::_verify_marked_complete_except_references:
252 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
253 "Must be marked in complete bitmap, except j.l.r.Reference referents");
254 break;
255 default:
256 assert(false, "Unhandled mark verification");
257 }
258
259 switch (_options._verify_forwarded) {
260 case ShenandoahVerifier::_verify_forwarded_disable:
261 // skip
262 break;
263 case ShenandoahVerifier::_verify_forwarded_none: {
264 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
265 "Should not be forwarded");
266 break;
267 }
268 case ShenandoahVerifier::_verify_forwarded_allow: {
269 if (obj != fwd) {
270 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
271 "Forwardee should be in another region");
272 }
273 break;
274 }
275 default:
276 assert(false, "Unhandled forwarding verification");
277 }
278
279 switch (_options._verify_cset) {
280 case ShenandoahVerifier::_verify_cset_disable:
281 // skip
282 break;
283 case ShenandoahVerifier::_verify_cset_none:
284 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
285 "Should not have references to collection set");
286 break;
287 case ShenandoahVerifier::_verify_cset_forwarded:
288 if (_heap->in_collection_set(obj)) {
289 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
290 "Object in collection set, should have forwardee");
291 }
292 break;
293 default:
294 assert(false, "Unhandled cset verification");
295 }
296
297 }
298
299 public:
300 /**
301 * Verify object with known interior reference.
302 * @param p interior reference where the object is referenced from; can be off-heap
303 * @param obj verified object
304 */
305 template <class T>
306 void verify_oop_at(T* p, oop obj) {
307 _interior_loc = p;
308 verify_oop(obj);
309 _interior_loc = nullptr;
310 }
311
312 /**
313 * Verify object without known interior reference.
314 * Useful when picking up the object at known offset in heap,
315 * but without knowing what objects reference it.
316 * @param obj verified object
317 */
318 void verify_oop_standalone(oop obj) {
319 _interior_loc = nullptr;
320 verify_oop(obj);
321 _interior_loc = nullptr;
322 }
323
324 /**
325 * Verify oop fields from this object.
326 * @param obj host object for verified fields
327 */
328 void verify_oops_from(oop obj) {
329 _loc = obj;
330 obj->oop_iterate(this);
331 _loc = nullptr;
332 }
333
334 virtual void do_oop(oop* p) override { do_oop_work(p); }
335 virtual void do_oop(narrowOop* p) override { do_oop_work(p); }
336 };
337
338 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
339 private:
340 size_t _used, _committed, _garbage;
341 public:
342 ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
343
344 void heap_region_do(ShenandoahHeapRegion* r) {
345 _used += r->used();
346 _garbage += r->garbage();
347 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
348 }
349
350 size_t used() { return _used; }
351 size_t committed() { return _committed; }
352 size_t garbage() { return _garbage; }
353 };
354
355 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
356 private:
357 ShenandoahHeap* _heap;
358 const char* _phase;
359 ShenandoahVerifier::VerifyRegions _regions;
360 public:
361 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
362 _heap(ShenandoahHeap::heap()),
363 _phase(phase),
364 _regions(regions) {};
365
366 void print_failure(ShenandoahHeapRegion* r, const char* label) {
367 ResourceMark rm;
368
369 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
370
371 stringStream ss;
372 r->print_on(&ss);
373 msg.append("%s", ss.as_string());
374
375 report_vm_error(__FILE__, __LINE__, msg.buffer());
376 }
377
378 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
379 if (!test) {
380 print_failure(r, msg);
381 }
382 }
383
384 void heap_region_do(ShenandoahHeapRegion* r) {
385 switch (_regions) {
386 case ShenandoahVerifier::_verify_regions_disable:
387 break;
388 case ShenandoahVerifier::_verify_regions_notrash:
389 verify(r, !r->is_trash(),
390 "Should not have trash regions");
391 break;
392 case ShenandoahVerifier::_verify_regions_nocset:
393 verify(r, !r->is_cset(),
394 "Should not have cset regions");
395 break;
396 case ShenandoahVerifier::_verify_regions_notrash_nocset:
397 verify(r, !r->is_trash(),
398 "Should not have trash regions");
399 verify(r, !r->is_cset(),
400 "Should not have cset regions");
401 break;
402 default:
403 ShouldNotReachHere();
404 }
405
406 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
407 "Capacity should match region size");
408
409 verify(r, r->bottom() <= r->top(),
410 "Region top should not be less than bottom");
411
412 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
413 "Region TAMS should not be less than bottom");
414
415 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
416 "Complete TAMS should not be larger than top");
417
418 verify(r, r->get_live_data_bytes() <= r->capacity(),
419 "Live data cannot be larger than capacity");
420
421 verify(r, r->garbage() <= r->capacity(),
422 "Garbage cannot be larger than capacity");
423
424 verify(r, r->used() <= r->capacity(),
425 "Used cannot be larger than capacity");
426
427 verify(r, r->get_shared_allocs() <= r->capacity(),
428 "Shared alloc count should not be larger than capacity");
429
430 verify(r, r->get_tlab_allocs() <= r->capacity(),
431 "TLAB alloc count should not be larger than capacity");
432
433 verify(r, r->get_gclab_allocs() <= r->capacity(),
434 "GCLAB alloc count should not be larger than capacity");
435
436 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
437 "Accurate accounting: shared + TLAB + GCLAB = used");
438
439 verify(r, !r->is_empty() || !r->has_live(),
440 "Empty regions should not have live data");
441
442 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
443 "Transitional: region flags and collection set agree");
444 }
445 };
446
447 class ShenandoahVerifierReachableTask : public WorkerTask {
448 private:
449 const char* _label;
450 ShenandoahVerifier::VerifyOptions _options;
451 ShenandoahHeap* _heap;
452 ShenandoahLivenessData* _ld;
453 MarkBitMap* _bitmap;
454 volatile size_t _processed;
455
456 public:
457 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
458 ShenandoahLivenessData* ld,
459 const char* label,
460 ShenandoahVerifier::VerifyOptions options) :
461 WorkerTask("Shenandoah Verifier Reachable Objects"),
462 _label(label),
463 _options(options),
464 _heap(ShenandoahHeap::heap()),
465 _ld(ld),
466 _bitmap(bitmap),
467 _processed(0) {};
468
469 size_t processed() {
470 return _processed;
471 }
472
473 virtual void work(uint worker_id) {
474 ResourceMark rm;
475 ShenandoahVerifierStack stack;
476
477 // On level 2, we need to only check the roots once.
478 // On level 3, we want to check the roots, and seed the local stack.
479 // It is a lesser evil to accept multiple root scans at level 3, because
480 // extended parallelism would buy us out.
481 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
482 || (ShenandoahVerifyLevel >= 3)) {
483 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
484 ShenandoahMessageBuffer("%s, Roots", _label),
485 _options);
486 if (_heap->unload_classes()) {
487 ShenandoahRootVerifier::strong_roots_do(&cl);
488 } else {
489 ShenandoahRootVerifier::roots_do(&cl);
490 }
491 }
492
493 size_t processed = 0;
494
495 if (ShenandoahVerifyLevel >= 3) {
496 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
497 ShenandoahMessageBuffer("%s, Reachable", _label),
498 _options);
499 while (!stack.is_empty()) {
500 processed++;
501 ShenandoahVerifierTask task = stack.pop();
502 cl.verify_oops_from(task.obj());
503 }
504 }
505
506 Atomic::add(&_processed, processed, memory_order_relaxed);
507 }
508 };
509
510 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
511 private:
512 const char* _label;
513 ShenandoahVerifier::VerifyOptions _options;
514 ShenandoahHeap *_heap;
515 MarkBitMap* _bitmap;
516 ShenandoahLivenessData* _ld;
517 volatile size_t _claimed;
518 volatile size_t _processed;
519
520 public:
521 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
522 ShenandoahLivenessData* ld,
523 const char* label,
524 ShenandoahVerifier::VerifyOptions options) :
525 WorkerTask("Shenandoah Verifier Marked Objects"),
526 _label(label),
527 _options(options),
528 _heap(ShenandoahHeap::heap()),
529 _bitmap(bitmap),
530 _ld(ld),
531 _claimed(0),
532 _processed(0) {};
533
534 size_t processed() {
535 return Atomic::load(&_processed);
536 }
537
538 virtual void work(uint worker_id) {
539 ShenandoahVerifierStack stack;
540 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
541 ShenandoahMessageBuffer("%s, Marked", _label),
542 _options);
543
544 while (true) {
545 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
546 if (v < _heap->num_regions()) {
547 ShenandoahHeapRegion* r = _heap->get_region(v);
548 if (!r->is_humongous() && !r->is_trash()) {
549 work_regular(r, stack, cl);
550 } else if (r->is_humongous_start()) {
551 work_humongous(r, stack, cl);
552 }
553 } else {
554 break;
555 }
556 }
557 }
558
559 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
560 size_t processed = 0;
561 HeapWord* obj = r->bottom();
562 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
563 verify_and_follow(obj, stack, cl, &processed);
564 }
565 Atomic::add(&_processed, processed, memory_order_relaxed);
566 }
567
568 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
569 size_t processed = 0;
570 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
571 HeapWord* tams = ctx->top_at_mark_start(r);
572
573 // Bitmaps, before TAMS
574 if (tams > r->bottom()) {
575 HeapWord* start = r->bottom();
576 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
577
578 while (addr < tams) {
579 verify_and_follow(addr, stack, cl, &processed);
580 addr += 1;
581 if (addr < tams) {
582 addr = ctx->get_next_marked_addr(addr, tams);
583 }
584 }
585 }
586
587 // Size-based, after TAMS
588 {
589 HeapWord* limit = r->top();
590 HeapWord* addr = tams;
591
592 while (addr < limit) {
593 verify_and_follow(addr, stack, cl, &processed);
594 addr += cast_to_oop(addr)->size();
595 }
596 }
597
598 Atomic::add(&_processed, processed, memory_order_relaxed);
599 }
600
601 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
602 if (!_bitmap->par_mark(addr)) return;
603
604 // Verify the object itself:
605 oop obj = cast_to_oop(addr);
606 cl.verify_oop_standalone(obj);
607
608 // Verify everything reachable from that object too, hopefully realizing
609 // everything was already marked, and never touching further:
610 if (!is_instance_ref_klass(obj->klass())) {
611 cl.verify_oops_from(obj);
612 (*processed)++;
613 }
614 while (!stack.is_empty()) {
615 ShenandoahVerifierTask task = stack.pop();
616 cl.verify_oops_from(task.obj());
617 (*processed)++;
618 }
619 }
620 };
621
622 class VerifyThreadGCState : public ThreadClosure {
623 private:
624 const char* const _label;
625 char const _expected;
626
627 public:
628 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
629 void do_thread(Thread* t) {
630 char actual = ShenandoahThreadLocalData::gc_state(t);
631 if (actual != _expected) {
632 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
633 }
634 }
635 };
636
637 void ShenandoahVerifier::verify_at_safepoint(const char *label,
638 VerifyForwarded forwarded, VerifyMarked marked,
639 VerifyCollectionSet cset,
640 VerifyLiveness liveness, VerifyRegions regions,
641 VerifyGCState gcstate) {
642 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
643 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
644
645 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
646
647 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
648 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
649
650 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
651
652 // GC state checks
653 {
654 char expected = -1;
655 bool enabled;
656 switch (gcstate) {
657 case _verify_gcstate_disable:
658 enabled = false;
659 break;
660 case _verify_gcstate_forwarded:
661 enabled = true;
662 expected = ShenandoahHeap::HAS_FORWARDED;
663 break;
664 case _verify_gcstate_stable:
665 enabled = true;
666 expected = ShenandoahHeap::STABLE;
667 break;
668 case _verify_gcstate_stable_weakroots:
669 enabled = true;
670 expected = ShenandoahHeap::STABLE;
671 if (!_heap->is_stw_gc_in_progress()) {
672 // Only concurrent GC sets this.
673 expected |= ShenandoahHeap::WEAK_ROOTS;
674 }
675 break;
676 default:
677 enabled = false;
678 assert(false, "Unhandled gc-state verification");
679 }
680
681 if (enabled) {
682 char actual = _heap->gc_state();
683 if (actual != expected) {
684 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
685 }
686
687 VerifyThreadGCState vtgcs(label, expected);
688 Threads::java_threads_do(&vtgcs);
689 }
690 }
691
692 // Deactivate barriers temporarily: Verifier wants plain heap accesses
693 ShenandoahGCStateResetter resetter;
694
695 // Heap size checks
696 {
697 ShenandoahHeapLocker lock(_heap->lock());
698
699 ShenandoahCalculateRegionStatsClosure cl;
700 _heap->heap_region_iterate(&cl);
701 size_t heap_used = _heap->used();
702 guarantee(cl.used() == heap_used,
703 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
704 label,
705 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
706 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
707
708 size_t heap_committed = _heap->committed();
709 guarantee(cl.committed() == heap_committed,
710 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
711 label,
712 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
713 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
714 }
715
716 // Internal heap region checks
717 if (ShenandoahVerifyLevel >= 1) {
718 ShenandoahVerifyHeapRegionClosure cl(label, regions);
719 _heap->heap_region_iterate(&cl);
720 }
721
722 OrderAccess::fence();
723
724 if (UseTLAB) {
725 _heap->labs_make_parsable();
726 }
727
728 // Allocate temporary bitmap for storing marking wavefront:
729 _verification_bit_map->clear();
730
731 // Allocate temporary array for storing liveness data
732 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
733 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
734
735 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
736
737 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
738 // This verifies what application can see, since it only cares about reachable objects.
739 size_t count_reachable = 0;
740 if (ShenandoahVerifyLevel >= 2) {
741 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
742 _heap->workers()->run_task(&task);
743 count_reachable = task.processed();
744 }
745
746 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
747 // not the application, can see during the region scans. There is no reason to process the objects
748 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
749 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
750 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
751 // version
752
753 size_t count_marked = 0;
754 if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
755 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
756 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
757 _heap->workers()->run_task(&task);
758 count_marked = task.processed();
759 } else {
760 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
761 }
762
763 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
764 // marked objects.
765
766 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
767 for (size_t i = 0; i < _heap->num_regions(); i++) {
768 ShenandoahHeapRegion* r = _heap->get_region(i);
769
770 juint verf_live = 0;
771 if (r->is_humongous()) {
772 // For humongous objects, test if start region is marked live, and if so,
773 // all humongous regions in that chain have live data equal to their "used".
774 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
775 if (start_live > 0) {
776 verf_live = (juint)(r->used() / HeapWordSize);
777 }
778 } else {
779 verf_live = Atomic::load(&ld[r->index()]);
780 }
781
782 size_t reg_live = r->get_live_data_words();
783 if (reg_live != verf_live) {
784 stringStream ss;
785 r->print_on(&ss);
786 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
787 label, reg_live, verf_live, ss.freeze());
788 }
789 }
790 }
791
792 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
793 label, ShenandoahVerifyLevel, count_reachable, count_marked);
794
795 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
796 }
797
798 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
799 verify_at_safepoint(
800 "Generic Verification",
801 _verify_forwarded_allow, // conservatively allow forwarded
802 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
803 _verify_cset_disable, // cset may be inconsistent
804 _verify_liveness_disable, // no reliable liveness data
805 _verify_regions_disable, // no reliable region data
806 _verify_gcstate_disable // no data about gcstate
807 );
808 }
809
810 void ShenandoahVerifier::verify_before_concmark() {
811 verify_at_safepoint(
812 "Before Mark",
813 _verify_forwarded_none, // UR should have fixed up
814 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
815 _verify_cset_none, // UR should have fixed this
816 _verify_liveness_disable, // no reliable liveness data
817 _verify_regions_notrash, // no trash regions
818 _verify_gcstate_stable // there are no forwarded objects
819 );
820 }
821
822 void ShenandoahVerifier::verify_after_concmark() {
823 verify_at_safepoint(
824 "After Mark",
825 _verify_forwarded_none, // no forwarded references
826 _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
827 _verify_cset_none, // no references to cset anymore
828 _verify_liveness_complete, // liveness data must be complete here
829 _verify_regions_disable, // trash regions not yet recycled
830 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
831 );
832 }
833
834 void ShenandoahVerifier::verify_before_evacuation() {
835 verify_at_safepoint(
836 "Before Evacuation",
837 _verify_forwarded_none, // no forwarded references
838 _verify_marked_complete_except_references, // walk over marked objects too
839 _verify_cset_disable, // non-forwarded references to cset expected
840 _verify_liveness_complete, // liveness data must be complete here
841 _verify_regions_disable, // trash regions not yet recycled
842 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
843 );
844 }
845
846 void ShenandoahVerifier::verify_before_updaterefs() {
847 verify_at_safepoint(
848 "Before Updating References",
849 _verify_forwarded_allow, // forwarded references allowed
850 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
851 _verify_cset_forwarded, // all cset refs are fully forwarded
852 _verify_liveness_disable, // no reliable liveness data anymore
853 _verify_regions_notrash, // trash regions have been recycled already
854 _verify_gcstate_forwarded // evacuation should have produced some forwarded objects
855 );
856 }
857
858 void ShenandoahVerifier::verify_after_updaterefs() {
859 verify_at_safepoint(
860 "After Updating References",
861 _verify_forwarded_none, // no forwarded references
862 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
863 _verify_cset_none, // no cset references, all updated
864 _verify_liveness_disable, // no reliable liveness data anymore
865 _verify_regions_nocset, // no cset regions, trash regions have appeared
866 _verify_gcstate_stable // update refs had cleaned up forwarded objects
867 );
868 }
869
870 void ShenandoahVerifier::verify_after_degenerated() {
871 verify_at_safepoint(
872 "After Degenerated GC",
873 _verify_forwarded_none, // all objects are non-forwarded
874 _verify_marked_complete, // all objects are marked in complete bitmap
875 _verify_cset_none, // no cset references
876 _verify_liveness_disable, // no reliable liveness data anymore
877 _verify_regions_notrash_nocset, // no trash, no cset
878 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
879 );
880 }
881
882 void ShenandoahVerifier::verify_before_fullgc() {
883 verify_at_safepoint(
884 "Before Full GC",
885 _verify_forwarded_allow, // can have forwarded objects
886 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
887 _verify_cset_disable, // cset might be foobared
888 _verify_liveness_disable, // no reliable liveness data anymore
889 _verify_regions_disable, // no reliable region data here
890 _verify_gcstate_disable // no reliable gcstate data
891 );
892 }
893
894 void ShenandoahVerifier::verify_after_fullgc() {
895 verify_at_safepoint(
896 "After Full GC",
897 _verify_forwarded_none, // all objects are non-forwarded
898 _verify_marked_complete, // all objects are marked in complete bitmap
899 _verify_cset_none, // no cset references
900 _verify_liveness_disable, // no reliable liveness data anymore
901 _verify_regions_notrash_nocset, // no trash, no cset
902 _verify_gcstate_stable // full gc cleaned up everything
903 );
904 }
905
906 class ShenandoahVerifyNoForwared : public OopClosure {
907 private:
908 template <class T>
909 void do_oop_work(T* p) {
910 T o = RawAccess<>::oop_load(p);
911 if (!CompressedOops::is_null(o)) {
912 oop obj = CompressedOops::decode_not_null(o);
913 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
914 if (obj != fwd) {
915 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
916 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
917 }
918 }
919 }
920
921 public:
922 void do_oop(narrowOop* p) { do_oop_work(p); }
923 void do_oop(oop* p) { do_oop_work(p); }
924 };
925
926 class ShenandoahVerifyInToSpaceClosure : public OopClosure {
927 private:
928 template <class T>
929 void do_oop_work(T* p) {
930 T o = RawAccess<>::oop_load(p);
931 if (!CompressedOops::is_null(o)) {
932 oop obj = CompressedOops::decode_not_null(o);
933 ShenandoahHeap* heap = ShenandoahHeap::heap();
934
935 if (!heap->marking_context()->is_marked(obj)) {
936 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
937 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
938 }
939
940 if (heap->in_collection_set(obj)) {
941 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
942 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
943 }
944
945 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
946 if (obj != fwd) {
947 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
948 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
949 }
950 }
951 }
952
953 public:
954 void do_oop(narrowOop* p) { do_oop_work(p); }
955 void do_oop(oop* p) { do_oop_work(p); }
956 };
957
958 void ShenandoahVerifier::verify_roots_in_to_space() {
959 ShenandoahVerifyInToSpaceClosure cl;
960 ShenandoahRootVerifier::roots_do(&cl);
961 }
962
963 void ShenandoahVerifier::verify_roots_no_forwarded() {
964 ShenandoahVerifyNoForwared cl;
965 ShenandoahRootVerifier::roots_do(&cl);
966 }