1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/shared/tlab_globals.hpp"
28 #include "gc/shenandoah/shenandoahAsserts.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
30 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
31 #include "gc/shenandoah/shenandoahGeneration.hpp"
32 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
34 #include "gc/shenandoah/shenandoahOldGeneration.hpp"
35 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
36 #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
37 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
38 #include "gc/shenandoah/shenandoahUtils.hpp"
39 #include "gc/shenandoah/shenandoahVerifier.hpp"
40 #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
41 #include "memory/allocation.hpp"
42 #include "memory/iterator.inline.hpp"
43 #include "memory/resourceArea.hpp"
44 #include "oops/compressedOops.inline.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/orderAccess.hpp"
47 #include "runtime/threads.hpp"
48 #include "utilities/align.hpp"
49
50 // Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)
51 #ifdef verify_oop
52 #undef verify_oop
53 #endif
54
55 static bool is_instance_ref_klass(Klass* k) {
56 return k->is_instance_klass() && InstanceKlass::cast(k)->reference_type() != REF_NONE;
57 }
58
59 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
60 private:
61 const char* _phase;
62 ShenandoahVerifier::VerifyOptions _options;
63 ShenandoahVerifierStack* _stack;
64 ShenandoahHeap* _heap;
65 MarkBitMap* _map;
66 ShenandoahLivenessData* _ld;
67 void* _interior_loc;
68 oop _loc;
69 ReferenceIterationMode _ref_mode;
70 ShenandoahGeneration* _generation;
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 _generation(nullptr) {
84 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
85 options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty ||
86 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
87 // Unknown status for Reference.referent field. Do not touch it, it might be dead.
88 // Normally, barriers would prevent us from seeing the dead referents, but verifier
89 // runs with barriers disabled.
90 _ref_mode = DO_FIELDS_EXCEPT_REFERENT;
91 } else {
92 // Otherwise do all fields.
93 _ref_mode = DO_FIELDS;
94 }
95
96 if (_heap->mode()->is_generational()) {
97 _generation = _heap->gc_generation();
98 assert(_generation != nullptr, "Expected active generation in this mode");
99 shenandoah_assert_generations_reconciled();
100 }
101 }
102
103 ReferenceIterationMode reference_iteration_mode() override {
104 return _ref_mode;
105 }
106
107 private:
108 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
109 if (!test) {
110 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
111 }
112 }
113
114 template <class T>
115 void do_oop_work(T* p) {
116 T o = RawAccess<>::oop_load(p);
117 if (!CompressedOops::is_null(o)) {
118 oop obj = CompressedOops::decode_not_null(o);
119 if (is_instance_ref_klass(ShenandoahForwarding::klass(obj))) {
120 obj = ShenandoahForwarding::get_forwardee(obj);
121 }
122 // Single threaded verification can use faster non-atomic stack and bitmap
123 // methods.
124 //
125 // For performance reasons, only fully verify non-marked field values.
126 // We are here when the host object for *p is already marked.
127 if (in_generation(obj) && _map->par_mark(obj)) {
128 verify_oop_at(p, obj);
129 _stack->push(ShenandoahVerifierTask(obj));
130 }
131 }
132 }
133
134 bool in_generation(oop obj) {
135 if (_generation == nullptr) {
136 return true;
137 }
138
139 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
140 return _generation->contains(region);
141 }
142
143 void verify_oop(oop obj) {
144 // Perform consistency checks with gradually decreasing safety level. This guarantees
145 // that failure report would not try to touch something that was not yet verified to be
146 // safe to process.
147
148 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in_reserved(obj),
149 "oop must be in heap bounds");
150 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
151 "oop must be aligned");
152
153 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
154 Klass* obj_klass = ShenandoahForwarding::klass(obj);
155
156 // Verify that obj is not in dead space:
157 {
158 // Do this before touching obj->size()
159 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
160 "Object klass pointer should not be null");
161 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
162 "Object klass pointer must go to metaspace");
163
164 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
165 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
166 "Object start should be within the region");
167
168 if (!obj_reg->is_humongous()) {
169 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + ShenandoahForwarding::size(obj)) <= obj_reg->top(),
170 "Object end should be within the region");
171 } else {
172 size_t humongous_start = obj_reg->index();
173 size_t humongous_end = humongous_start + (ShenandoahForwarding::size(obj) >> ShenandoahHeapRegion::region_size_words_shift());
174 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
175 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
176 "Humongous object is in continuation that fits it");
177 }
178 }
179
180 // ------------ obj is safe at this point --------------
181
182 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
183 "Object should be in active region");
184
185 switch (_options._verify_liveness) {
186 case ShenandoahVerifier::_verify_liveness_disable:
187 // skip
188 break;
189 case ShenandoahVerifier::_verify_liveness_complete:
190 Atomic::add(&_ld[obj_reg->index()], (uint) ShenandoahForwarding::size(obj), memory_order_relaxed);
191 // fallthrough for fast failure for un-live regions:
192 case ShenandoahVerifier::_verify_liveness_conservative:
193 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
194 (obj_reg->is_old() && _heap->gc_generation()->is_young()),
195 "Object must belong to region with live data");
196 shenandoah_assert_generations_reconciled();
197 break;
198 default:
199 assert(false, "Unhandled liveness verification");
200 }
201 }
202
203 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
204
205 ShenandoahHeapRegion* fwd_reg = nullptr;
206
207 if (obj != fwd) {
208 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in_reserved(fwd),
209 "Forwardee must be in heap bounds");
210 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
211 "Forwardee is set");
212 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
213 "Forwardee must be aligned");
214
215 // Do this before touching fwd->size()
216 Klass* fwd_klass = fwd->klass_or_null();
217 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != nullptr,
218 "Forwardee klass pointer should not be null");
219 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
220 "Forwardee klass pointer must go to metaspace");
221 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
222 "Forwardee klass pointer must go to metaspace");
223
224 fwd_reg = _heap->heap_region_containing(fwd);
225
226 check(ShenandoahAsserts::_safe_oop, obj, fwd_reg->is_active(),
227 "Forwardee should be in active region");
228
229 // Verify that forwardee is not in the dead space:
230 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
231 "Should have no humongous forwardees");
232
233 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
234 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
235 "Forwardee start should be within the region");
236 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + ShenandoahForwarding::size(fwd)) <= fwd_reg->top(),
237 "Forwardee end should be within the region");
238
239 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
240 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
241 "Double forwarding");
242 } else {
243 fwd_reg = obj_reg;
244 }
245
246 // Do additional checks for special objects: their fields can hold metadata as well.
247 // We want to check class loading/unloading did not corrupt them.
248
249 if (obj_klass == vmClasses::Class_klass()) {
250 Metadata* klass = obj->metadata_field(java_lang_Class::klass_offset());
251 check(ShenandoahAsserts::_safe_oop, obj,
252 klass == nullptr || Metaspace::contains(klass),
253 "Instance class mirror should point to Metaspace");
254
255 Metadata* array_klass = obj->metadata_field(java_lang_Class::array_klass_offset());
256 check(ShenandoahAsserts::_safe_oop, obj,
257 array_klass == nullptr || Metaspace::contains(array_klass),
258 "Array class mirror should point to Metaspace");
259 }
260
261 // ------------ obj and fwd are safe at this point --------------
262 switch (_options._verify_marked) {
263 case ShenandoahVerifier::_verify_marked_disable:
264 // skip
265 break;
266 case ShenandoahVerifier::_verify_marked_incomplete:
267 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
268 "Must be marked in incomplete bitmap");
269 break;
270 case ShenandoahVerifier::_verify_marked_complete:
271 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
272 "Must be marked in complete bitmap");
273 break;
274 case ShenandoahVerifier::_verify_marked_complete_except_references:
275 case ShenandoahVerifier::_verify_marked_complete_satb_empty:
276 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
277 "Must be marked in complete bitmap, except j.l.r.Reference referents");
278 break;
279 default:
280 assert(false, "Unhandled mark verification");
281 }
282
283 switch (_options._verify_forwarded) {
284 case ShenandoahVerifier::_verify_forwarded_disable:
285 // skip
286 break;
287 case ShenandoahVerifier::_verify_forwarded_none: {
288 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
289 "Should not be forwarded");
290 break;
291 }
292 case ShenandoahVerifier::_verify_forwarded_allow: {
293 if (obj != fwd) {
294 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
295 "Forwardee should be in another region");
296 }
297 break;
298 }
299 default:
300 assert(false, "Unhandled forwarding verification");
301 }
302
303 switch (_options._verify_cset) {
304 case ShenandoahVerifier::_verify_cset_disable:
305 // skip
306 break;
307 case ShenandoahVerifier::_verify_cset_none:
308 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
309 "Should not have references to collection set");
310 break;
311 case ShenandoahVerifier::_verify_cset_forwarded:
312 if (_heap->in_collection_set(obj)) {
313 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
314 "Object in collection set, should have forwardee");
315 }
316 break;
317 default:
318 assert(false, "Unhandled cset verification");
319 }
320
321 }
322
323 public:
324 /**
325 * Verify object with known interior reference.
326 * @param p interior reference where the object is referenced from; can be off-heap
327 * @param obj verified object
328 */
329 template <class T>
330 void verify_oop_at(T* p, oop obj) {
331 _interior_loc = p;
332 verify_oop(obj);
333 _interior_loc = nullptr;
334 }
335
336 /**
337 * Verify object without known interior reference.
338 * Useful when picking up the object at known offset in heap,
339 * but without knowing what objects reference it.
340 * @param obj verified object
341 */
342 void verify_oop_standalone(oop obj) {
343 _interior_loc = nullptr;
344 verify_oop(obj);
345 _interior_loc = nullptr;
346 }
347
348 /**
349 * Verify oop fields from this object.
350 * @param obj host object for verified fields
351 */
352 void verify_oops_from(oop obj) {
353 _loc = obj;
354 // oop_iterate() can not deal with forwarded objects, because
355 // it needs to load klass(), which may be overridden by the
356 // forwarding pointer.
357 oop fwd = ShenandoahForwarding::get_forwardee_raw(obj);
358 fwd->oop_iterate(this);
359 _loc = nullptr;
360 }
361
362 void do_oop(oop* p) override { do_oop_work(p); }
363 void do_oop(narrowOop* p) override { do_oop_work(p); }
364 };
365
366 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
367 // a subset (e.g. the young generation or old generation) of the total heap.
368 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
369 private:
370 size_t _used, _committed, _garbage, _regions, _humongous_waste, _trashed_regions;
371 public:
372 ShenandoahCalculateRegionStatsClosure() :
373 _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0), _trashed_regions(0) {};
374
375 void heap_region_do(ShenandoahHeapRegion* r) override {
376 _used += r->used();
377 _garbage += r->garbage();
378 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
379 if (r->is_humongous()) {
380 _humongous_waste += r->free();
381 }
382 if (r->is_trash()) {
383 _trashed_regions++;
384 }
385 _regions++;
386 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
387 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
388 }
389
390 size_t used() const { return _used; }
391 size_t committed() const { return _committed; }
392 size_t garbage() const { return _garbage; }
393 size_t regions() const { return _regions; }
394 size_t waste() const { return _humongous_waste; }
395
396 // span is the total memory affiliated with these stats (some of which is in use and other is available)
397 size_t span() const { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
398 size_t non_trashed_span() const { return (_regions - _trashed_regions) * ShenandoahHeapRegion::region_size_bytes(); }
399 };
400
401 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
402 public:
403 ShenandoahCalculateRegionStatsClosure old;
404 ShenandoahCalculateRegionStatsClosure young;
405 ShenandoahCalculateRegionStatsClosure global;
406
407 void heap_region_do(ShenandoahHeapRegion* r) override {
408 switch (r->affiliation()) {
409 case FREE:
410 return;
411 case YOUNG_GENERATION:
412 young.heap_region_do(r);
413 global.heap_region_do(r);
414 break;
415 case OLD_GENERATION:
416 old.heap_region_do(r);
417 global.heap_region_do(r);
418 break;
419 default:
420 ShouldNotReachHere();
421 }
422 }
423
424 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
425 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
426 generation->name(),
427 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
428 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
429 }
430
431 static void validate_usage(const bool adjust_for_padding,
432 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
433 ShenandoahHeap* heap = ShenandoahHeap::heap();
434 size_t generation_used = generation->used();
435 size_t generation_used_regions = generation->used_regions();
436 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
437 size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
438 generation_used += pad;
439 }
440
441 guarantee(stats.used() == generation_used,
442 "%s: generation (%s) used size must be consistent: generation-used: " PROPERFMT ", regions-used: " PROPERFMT,
443 label, generation->name(), PROPERFMTARGS(generation_used), PROPERFMTARGS(stats.used()));
444
445 guarantee(stats.regions() == generation_used_regions,
446 "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
447 label, generation->name(), generation->used_regions(), stats.regions());
448
449 size_t generation_capacity = generation->max_capacity();
450 guarantee(stats.non_trashed_span() <= generation_capacity,
451 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") * region size (" PROPERFMT
452 ") must not exceed current capacity (" PROPERFMT ")",
453 label, generation->name(), stats.regions(), PROPERFMTARGS(ShenandoahHeapRegion::region_size_bytes()),
454 PROPERFMTARGS(generation_capacity));
455
456 size_t humongous_waste = generation->get_humongous_waste();
457 guarantee(stats.waste() == humongous_waste,
458 "%s: generation (%s) humongous waste must be consistent: generation: " PROPERFMT ", regions: " PROPERFMT,
459 label, generation->name(), PROPERFMTARGS(humongous_waste), PROPERFMTARGS(stats.waste()));
460 }
461 };
462
463 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
464 private:
465 ShenandoahHeap* _heap;
466 const char* _phase;
467 ShenandoahVerifier::VerifyRegions _regions;
468 public:
469 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
470 _heap(ShenandoahHeap::heap()),
471 _phase(phase),
472 _regions(regions) {};
473
474 void print_failure(ShenandoahHeapRegion* r, const char* label) {
475 ResourceMark rm;
476
477 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
478
479 stringStream ss;
480 r->print_on(&ss);
481 msg.append("%s", ss.as_string());
482
483 report_vm_error(__FILE__, __LINE__, msg.buffer());
484 }
485
486 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
487 if (!test) {
488 print_failure(r, msg);
489 }
490 }
491
492 void heap_region_do(ShenandoahHeapRegion* r) override {
493 switch (_regions) {
494 case ShenandoahVerifier::_verify_regions_disable:
495 break;
496 case ShenandoahVerifier::_verify_regions_notrash:
497 verify(r, !r->is_trash(),
498 "Should not have trash regions");
499 break;
500 case ShenandoahVerifier::_verify_regions_nocset:
501 verify(r, !r->is_cset(),
502 "Should not have cset regions");
503 break;
504 case ShenandoahVerifier::_verify_regions_notrash_nocset:
505 verify(r, !r->is_trash(),
506 "Should not have trash regions");
507 verify(r, !r->is_cset(),
508 "Should not have cset regions");
509 break;
510 default:
511 ShouldNotReachHere();
512 }
513
514 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
515 "Capacity should match region size");
516
517 verify(r, r->bottom() <= r->top(),
518 "Region top should not be less than bottom");
519
520 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
521 "Region TAMS should not be less than bottom");
522
523 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
524 "Complete TAMS should not be larger than top");
525
526 verify(r, r->get_live_data_bytes() <= r->capacity(),
527 "Live data cannot be larger than capacity");
528
529 verify(r, r->garbage() <= r->capacity(),
530 "Garbage cannot be larger than capacity");
531
532 verify(r, r->used() <= r->capacity(),
533 "Used cannot be larger than capacity");
534
535 verify(r, r->get_shared_allocs() <= r->capacity(),
536 "Shared alloc count should not be larger than capacity");
537
538 verify(r, r->get_tlab_allocs() <= r->capacity(),
539 "TLAB alloc count should not be larger than capacity");
540
541 verify(r, r->get_gclab_allocs() <= r->capacity(),
542 "GCLAB alloc count should not be larger than capacity");
543
544 verify(r, r->get_plab_allocs() <= r->capacity(),
545 "PLAB alloc count should not be larger than capacity");
546
547 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
548 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
549
550 verify(r, !r->is_empty() || !r->has_live(),
551 "Empty regions should not have live data");
552
553 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
554 "Transitional: region flags and collection set agree");
555 }
556 };
557
558 class ShenandoahVerifierReachableTask : public WorkerTask {
559 private:
560 const char* _label;
561 ShenandoahVerifier::VerifyOptions _options;
562 ShenandoahHeap* _heap;
563 ShenandoahLivenessData* _ld;
564 MarkBitMap* _bitmap;
565 volatile size_t _processed;
566
567 public:
568 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
569 ShenandoahLivenessData* ld,
570 const char* label,
571 ShenandoahVerifier::VerifyOptions options) :
572 WorkerTask("Shenandoah Verifier Reachable Objects"),
573 _label(label),
574 _options(options),
575 _heap(ShenandoahHeap::heap()),
576 _ld(ld),
577 _bitmap(bitmap),
578 _processed(0) {};
579
580 size_t processed() const {
581 return _processed;
582 }
583
584 void work(uint worker_id) override {
585 ResourceMark rm;
586 ShenandoahVerifierStack stack;
587
588 // On level 2, we need to only check the roots once.
589 // On level 3, we want to check the roots, and seed the local stack.
590 // It is a lesser evil to accept multiple root scans at level 3, because
591 // extended parallelism would buy us out.
592 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
593 || (ShenandoahVerifyLevel >= 3)) {
594 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
595 ShenandoahMessageBuffer("%s, Roots", _label),
596 _options);
597 if (_heap->unload_classes()) {
598 ShenandoahRootVerifier::strong_roots_do(&cl);
599 } else {
600 ShenandoahRootVerifier::roots_do(&cl);
601 }
602 }
603
604 size_t processed = 0;
605
606 if (ShenandoahVerifyLevel >= 3) {
607 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
608 ShenandoahMessageBuffer("%s, Reachable", _label),
609 _options);
610 while (!stack.is_empty()) {
611 processed++;
612 ShenandoahVerifierTask task = stack.pop();
613 cl.verify_oops_from(task.obj());
614 }
615 }
616
617 Atomic::add(&_processed, processed, memory_order_relaxed);
618 }
619 };
620
621 class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
622 public:
623 void do_thread(Thread* thread) override {
624 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
625 if (!queue.is_empty()) {
626 fatal("All SATB buffers should have been flushed during mark");
627 }
628 }
629 };
630
631 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
632 private:
633 const char* _label;
634 ShenandoahVerifier::VerifyOptions _options;
635 ShenandoahHeap *_heap;
636 MarkBitMap* _bitmap;
637 ShenandoahLivenessData* _ld;
638 volatile size_t _claimed;
639 volatile size_t _processed;
640 ShenandoahGeneration* _generation;
641
642 public:
643 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
644 ShenandoahLivenessData* ld,
645 const char* label,
646 ShenandoahVerifier::VerifyOptions options) :
647 WorkerTask("Shenandoah Verifier Marked Objects"),
648 _label(label),
649 _options(options),
650 _heap(ShenandoahHeap::heap()),
651 _bitmap(bitmap),
652 _ld(ld),
653 _claimed(0),
654 _processed(0),
655 _generation(nullptr) {
656 if (_heap->mode()->is_generational()) {
657 _generation = _heap->gc_generation();
658 assert(_generation != nullptr, "Expected active generation in this mode.");
659 shenandoah_assert_generations_reconciled();
660 }
661 };
662
663 size_t processed() {
664 return Atomic::load(&_processed);
665 }
666
667 void work(uint worker_id) override {
668 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
669 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
670 Threads::threads_do(&verify_satb);
671 }
672
673 ShenandoahVerifierStack stack;
674 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
675 ShenandoahMessageBuffer("%s, Marked", _label),
676 _options);
677
678 while (true) {
679 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
680 if (v < _heap->num_regions()) {
681 ShenandoahHeapRegion* r = _heap->get_region(v);
682 if (!in_generation(r)) {
683 continue;
684 }
685
686 if (!r->is_humongous() && !r->is_trash()) {
687 work_regular(r, stack, cl);
688 } else if (r->is_humongous_start()) {
689 work_humongous(r, stack, cl);
690 }
691 } else {
692 break;
693 }
694 }
695 }
696
697 bool in_generation(ShenandoahHeapRegion* r) {
698 return _generation == nullptr || _generation->contains(r);
699 }
700
701 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
702 size_t processed = 0;
703 HeapWord* obj = r->bottom();
704 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
705 verify_and_follow(obj, stack, cl, &processed);
706 }
707 Atomic::add(&_processed, processed, memory_order_relaxed);
708 }
709
710 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
711 size_t processed = 0;
712 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
713 HeapWord* tams = ctx->top_at_mark_start(r);
714
715 // Bitmaps, before TAMS
716 if (tams > r->bottom()) {
717 HeapWord* start = r->bottom();
718 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
719
720 while (addr < tams) {
721 verify_and_follow(addr, stack, cl, &processed);
722 addr += 1;
723 if (addr < tams) {
724 addr = ctx->get_next_marked_addr(addr, tams);
725 }
726 }
727 }
728
729 // Size-based, after TAMS
730 {
731 HeapWord* limit = r->top();
732 HeapWord* addr = tams;
733
734 while (addr < limit) {
735 verify_and_follow(addr, stack, cl, &processed);
736 addr += ShenandoahForwarding::size(cast_to_oop(addr));
737 }
738 }
739
740 Atomic::add(&_processed, processed, memory_order_relaxed);
741 }
742
743 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
744 if (!_bitmap->par_mark(addr)) return;
745
746 // Verify the object itself:
747 oop obj = cast_to_oop(addr);
748 cl.verify_oop_standalone(obj);
749
750 // Verify everything reachable from that object too, hopefully realizing
751 // everything was already marked, and never touching further:
752 if (!is_instance_ref_klass(ShenandoahForwarding::klass(obj))) {
753 cl.verify_oops_from(obj);
754 (*processed)++;
755 }
756 while (!stack.is_empty()) {
757 ShenandoahVerifierTask task = stack.pop();
758 cl.verify_oops_from(task.obj());
759 (*processed)++;
760 }
761 }
762 };
763
764 class VerifyThreadGCState : public ThreadClosure {
765 private:
766 const char* const _label;
767 char const _expected;
768
769 public:
770 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
771 void do_thread(Thread* t) override {
772 char actual = ShenandoahThreadLocalData::gc_state(t);
773 if (!verify_gc_state(actual, _expected)) {
774 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
775 }
776 }
777
778 static bool verify_gc_state(char actual, char expected) {
779 // Old generation marking is allowed in all states.
780 if (ShenandoahHeap::heap()->mode()->is_generational()) {
781 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
782 } else {
783 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
784 return (actual == expected);
785 }
786 }
787 };
788
789 void ShenandoahVerifier::verify_at_safepoint(const char* label,
790 VerifyRememberedSet remembered,
791 VerifyForwarded forwarded, VerifyMarked marked,
792 VerifyCollectionSet cset,
793 VerifyLiveness liveness, VerifyRegions regions,
794 VerifySize sizeness,
795 VerifyGCState gcstate) {
796 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
797 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
798
799 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
800
801 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
802 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
803
804 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
805
806 // GC state checks
807 {
808 char expected = -1;
809 bool enabled;
810 switch (gcstate) {
811 case _verify_gcstate_disable:
812 enabled = false;
813 break;
814 case _verify_gcstate_forwarded:
815 enabled = true;
816 expected = ShenandoahHeap::HAS_FORWARDED;
817 break;
818 case _verify_gcstate_updating:
819 enabled = true;
820 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
821 break;
822 case _verify_gcstate_stable:
823 enabled = true;
824 expected = ShenandoahHeap::STABLE;
825 break;
826 case _verify_gcstate_stable_weakroots:
827 enabled = true;
828 expected = ShenandoahHeap::STABLE;
829 if (!_heap->is_stw_gc_in_progress()) {
830 // Only concurrent GC sets this.
831 expected |= ShenandoahHeap::WEAK_ROOTS;
832 }
833 break;
834 default:
835 enabled = false;
836 assert(false, "Unhandled gc-state verification");
837 }
838
839 if (enabled) {
840 char actual = _heap->gc_state();
841
842 bool is_marking = (actual & ShenandoahHeap::MARKING);
843 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
844 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
845
846 // Old generation marking is allowed in all states.
847 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
848 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
849 }
850
851 VerifyThreadGCState vtgcs(label, expected);
852 Threads::java_threads_do(&vtgcs);
853 }
854 }
855
856 // Deactivate barriers temporarily: Verifier wants plain heap accesses
857 ShenandoahGCStateResetter resetter;
858
859 // Heap size checks
860 {
861 ShenandoahHeapLocker lock(_heap->lock());
862
863 ShenandoahCalculateRegionStatsClosure cl;
864 _heap->heap_region_iterate(&cl);
865 size_t heap_used;
866 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
867 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
868 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
869 } else if (sizeness != _verify_size_disable) {
870 heap_used = _heap->used();
871 }
872 if (sizeness != _verify_size_disable) {
873 guarantee(cl.used() == heap_used,
874 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
875 label,
876 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
877 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
878 }
879 size_t heap_committed = _heap->committed();
880 guarantee(cl.committed() == heap_committed,
881 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
882 label,
883 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
884 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
885 }
886
887 log_debug(gc)("Safepoint verification finished heap usage verification");
888
889 ShenandoahGeneration* generation;
890 if (_heap->mode()->is_generational()) {
891 generation = _heap->gc_generation();
892 guarantee(generation != nullptr, "Need to know which generation to verify.");
893 shenandoah_assert_generations_reconciled();
894 } else {
895 generation = nullptr;
896 }
897
898 if (generation != nullptr) {
899 ShenandoahHeapLocker lock(_heap->lock());
900
901 switch (remembered) {
902 case _verify_remembered_disable:
903 break;
904 case _verify_remembered_before_marking:
905 log_debug(gc)("Safepoint verification of remembered set at mark");
906 verify_rem_set_before_mark();
907 break;
908 case _verify_remembered_before_updating_references:
909 log_debug(gc)("Safepoint verification of remembered set at update ref");
910 verify_rem_set_before_update_ref();
911 break;
912 case _verify_remembered_after_full_gc:
913 log_debug(gc)("Safepoint verification of remembered set after full gc");
914 verify_rem_set_after_full_gc();
915 break;
916 default:
917 fatal("Unhandled remembered set verification mode");
918 }
919
920 ShenandoahGenerationStatsClosure cl;
921 _heap->heap_region_iterate(&cl);
922
923 if (LogTarget(Debug, gc)::is_enabled()) {
924 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
925 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
926 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
927 }
928 if (sizeness == _verify_size_adjusted_for_padding) {
929 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
930 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
931 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
932 } else if (sizeness == _verify_size_exact) {
933 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
934 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
935 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
936 }
937 // else: sizeness must equal _verify_size_disable
938 }
939
940 log_debug(gc)("Safepoint verification finished remembered set verification");
941
942 // Internal heap region checks
943 if (ShenandoahVerifyLevel >= 1) {
944 ShenandoahVerifyHeapRegionClosure cl(label, regions);
945 if (generation != nullptr) {
946 generation->heap_region_iterate(&cl);
947 } else {
948 _heap->heap_region_iterate(&cl);
949 }
950 }
951
952 log_debug(gc)("Safepoint verification finished heap region closure verification");
953
954 OrderAccess::fence();
955
956 if (UseTLAB) {
957 _heap->labs_make_parsable();
958 }
959
960 // Allocate temporary bitmap for storing marking wavefront:
961 _verification_bit_map->clear();
962
963 // Allocate temporary array for storing liveness data
964 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
965 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
966
967 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
968
969 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
970 // This verifies what application can see, since it only cares about reachable objects.
971 size_t count_reachable = 0;
972 if (ShenandoahVerifyLevel >= 2) {
973 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
974 _heap->workers()->run_task(&task);
975 count_reachable = task.processed();
976 }
977
978 log_debug(gc)("Safepoint verification finished getting initial reachable set");
979
980 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
981 // not the application, can see during the region scans. There is no reason to process the objects
982 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
983 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
984 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
985 // version
986
987 size_t count_marked = 0;
988 if (ShenandoahVerifyLevel >= 4 &&
989 (marked == _verify_marked_complete ||
990 marked == _verify_marked_complete_except_references ||
991 marked == _verify_marked_complete_satb_empty)) {
992 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
993 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
994 _heap->workers()->run_task(&task);
995 count_marked = task.processed();
996 } else {
997 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
998 }
999
1000 log_debug(gc)("Safepoint verification finished walking marked objects");
1001
1002 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
1003 // marked objects.
1004
1005 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
1006 for (size_t i = 0; i < _heap->num_regions(); i++) {
1007 ShenandoahHeapRegion* r = _heap->get_region(i);
1008 if (generation != nullptr && !generation->contains(r)) {
1009 continue;
1010 }
1011
1012 juint verf_live = 0;
1013 if (r->is_humongous()) {
1014 // For humongous objects, test if start region is marked live, and if so,
1015 // all humongous regions in that chain have live data equal to their "used".
1016 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1017 if (start_live > 0) {
1018 verf_live = (juint)(r->used() / HeapWordSize);
1019 }
1020 } else {
1021 verf_live = Atomic::load(&ld[r->index()]);
1022 }
1023
1024 size_t reg_live = r->get_live_data_words();
1025 if (reg_live != verf_live) {
1026 stringStream ss;
1027 r->print_on(&ss);
1028 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
1029 label, reg_live, verf_live, ss.freeze());
1030 }
1031 }
1032 }
1033
1034 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1035
1036
1037 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
1038 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1039
1040 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1041 }
1042
1043 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1044 verify_at_safepoint(
1045 "Generic Verification",
1046 _verify_remembered_disable, // do not verify remembered set
1047 _verify_forwarded_allow, // conservatively allow forwarded
1048 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1049 _verify_cset_disable, // cset may be inconsistent
1050 _verify_liveness_disable, // no reliable liveness data
1051 _verify_regions_disable, // no reliable region data
1052 _verify_size_exact, // expect generation and heap sizes to match exactly
1053 _verify_gcstate_disable // no data about gcstate
1054 );
1055 }
1056
1057 void ShenandoahVerifier::verify_before_concmark() {
1058 verify_at_safepoint(
1059 "Before Mark",
1060 _verify_remembered_before_marking,
1061 // verify read-only remembered set from bottom() to top()
1062 _verify_forwarded_none, // UR should have fixed up
1063 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1064 _verify_cset_none, // UR should have fixed this
1065 _verify_liveness_disable, // no reliable liveness data
1066 _verify_regions_notrash, // no trash regions
1067 _verify_size_exact, // expect generation and heap sizes to match exactly
1068 _verify_gcstate_stable // there are no forwarded objects
1069 );
1070 }
1071
1072 void ShenandoahVerifier::verify_after_concmark() {
1073 verify_at_safepoint(
1074 "After Mark",
1075 _verify_remembered_disable, // do not verify remembered set
1076 _verify_forwarded_none, // no forwarded references
1077 _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
1078 _verify_cset_none, // no references to cset anymore
1079 _verify_liveness_complete, // liveness data must be complete here
1080 _verify_regions_disable, // trash regions not yet recycled
1081 _verify_size_exact, // expect generation and heap sizes to match exactly
1082 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1083 );
1084 }
1085
1086 void ShenandoahVerifier::verify_after_concmark_with_promotions() {
1087 verify_at_safepoint(
1088 "After Mark",
1089 _verify_remembered_disable, // do not verify remembered set
1090 _verify_forwarded_none, // no forwarded references
1091 _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
1092 _verify_cset_none, // no references to cset anymore
1093 _verify_liveness_complete, // liveness data must be complete here
1094 _verify_regions_disable, // trash regions not yet recycled
1095 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1096 // for promote in place padding
1097 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1098 );
1099 }
1100
1101 void ShenandoahVerifier::verify_before_evacuation() {
1102 verify_at_safepoint(
1103 "Before Evacuation",
1104 _verify_remembered_disable, // do not verify remembered set
1105 _verify_forwarded_none, // no forwarded references
1106 _verify_marked_complete_except_references, // walk over marked objects too
1107 _verify_cset_disable, // non-forwarded references to cset expected
1108 _verify_liveness_complete, // liveness data must be complete here
1109 _verify_regions_disable, // trash regions not yet recycled
1110 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1111 // for promote in place padding
1112 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1113 );
1114 }
1115
1116 void ShenandoahVerifier::verify_before_updaterefs() {
1117 verify_at_safepoint(
1118 "Before Updating References",
1119 _verify_remembered_before_updating_references, // verify read-write remembered set
1120 _verify_forwarded_allow, // forwarded references allowed
1121 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1122 _verify_cset_forwarded, // all cset refs are fully forwarded
1123 _verify_liveness_disable, // no reliable liveness data anymore
1124 _verify_regions_notrash, // trash regions have been recycled already
1125 _verify_size_exact, // expect generation and heap sizes to match exactly
1126 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1127 );
1128 }
1129
1130 // We have not yet cleanup (reclaimed) the collection set
1131 void ShenandoahVerifier::verify_after_updaterefs() {
1132 verify_at_safepoint(
1133 "After Updating References",
1134 _verify_remembered_disable, // do not verify remembered set
1135 _verify_forwarded_none, // no forwarded references
1136 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1137 _verify_cset_none, // no cset references, all updated
1138 _verify_liveness_disable, // no reliable liveness data anymore
1139 _verify_regions_nocset, // no cset regions, trash regions have appeared
1140 _verify_size_exact, // expect generation and heap sizes to match exactly
1141 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1142 );
1143 }
1144
1145 void ShenandoahVerifier::verify_after_degenerated() {
1146 verify_at_safepoint(
1147 "After Degenerated GC",
1148 _verify_remembered_disable, // do not verify remembered set
1149 _verify_forwarded_none, // all objects are non-forwarded
1150 _verify_marked_complete, // all objects are marked in complete bitmap
1151 _verify_cset_none, // no cset references
1152 _verify_liveness_disable, // no reliable liveness data anymore
1153 _verify_regions_notrash_nocset, // no trash, no cset
1154 _verify_size_exact, // expect generation and heap sizes to match exactly
1155 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1156 );
1157 }
1158
1159 void ShenandoahVerifier::verify_before_fullgc() {
1160 verify_at_safepoint(
1161 "Before Full GC",
1162 _verify_remembered_disable, // do not verify remembered set
1163 _verify_forwarded_allow, // can have forwarded objects
1164 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1165 _verify_cset_disable, // cset might be foobared
1166 _verify_liveness_disable, // no reliable liveness data anymore
1167 _verify_regions_disable, // no reliable region data here
1168 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1169 _verify_gcstate_disable // no reliable gcstate data
1170 );
1171 }
1172
1173 void ShenandoahVerifier::verify_after_fullgc() {
1174 verify_at_safepoint(
1175 "After Full GC",
1176 _verify_remembered_after_full_gc, // verify read-write remembered set
1177 _verify_forwarded_none, // all objects are non-forwarded
1178 _verify_marked_complete, // all objects are marked in complete bitmap
1179 _verify_cset_none, // no cset references
1180 _verify_liveness_disable, // no reliable liveness data anymore
1181 _verify_regions_notrash_nocset, // no trash, no cset
1182 _verify_size_exact, // expect generation and heap sizes to match exactly
1183 _verify_gcstate_stable // full gc cleaned up everything
1184 );
1185 }
1186
1187 class ShenandoahVerifyNoForwarded : public BasicOopIterateClosure {
1188 private:
1189 template <class T>
1190 void do_oop_work(T* p) {
1191 T o = RawAccess<>::oop_load(p);
1192 if (!CompressedOops::is_null(o)) {
1193 oop obj = CompressedOops::decode_not_null(o);
1194 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1195 if (obj != fwd) {
1196 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1197 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1198 }
1199 }
1200 }
1201
1202 public:
1203 void do_oop(narrowOop* p) { do_oop_work(p); }
1204 void do_oop(oop* p) { do_oop_work(p); }
1205 };
1206
1207 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1208 private:
1209 template <class T>
1210 void do_oop_work(T* p) {
1211 T o = RawAccess<>::oop_load(p);
1212 if (!CompressedOops::is_null(o)) {
1213 oop obj = CompressedOops::decode_not_null(o);
1214 ShenandoahHeap* heap = ShenandoahHeap::heap();
1215
1216 if (!heap->marking_context()->is_marked_or_old(obj)) {
1217 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1218 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1219 }
1220
1221 if (heap->in_collection_set(obj)) {
1222 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1223 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1224 }
1225
1226 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1227 if (obj != fwd) {
1228 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1229 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1230 }
1231 }
1232 }
1233
1234 public:
1235 void do_oop(narrowOop* p) override { do_oop_work(p); }
1236 void do_oop(oop* p) override { do_oop_work(p); }
1237 };
1238
1239 void ShenandoahVerifier::verify_roots_in_to_space() {
1240 ShenandoahVerifyInToSpaceClosure cl;
1241 ShenandoahRootVerifier::roots_do(&cl);
1242 }
1243
1244 void ShenandoahVerifier::verify_roots_no_forwarded() {
1245 ShenandoahVerifyNoForwarded cl;
1246 ShenandoahRootVerifier::roots_do(&cl);
1247 }
1248
1249 template<typename Scanner>
1250 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1251 protected:
1252 ShenandoahGenerationalHeap* const _heap;
1253 Scanner* const _scanner;
1254 const char* _message;
1255
1256 public:
1257 // Argument distinguishes between initial mark or start of update refs verification.
1258 explicit ShenandoahVerifyRemSetClosure(Scanner* scanner, const char* message) :
1259 _heap(ShenandoahGenerationalHeap::heap()),
1260 _scanner(scanner),
1261 _message(message) {}
1262
1263 template<class T>
1264 inline void work(T* p) {
1265 T o = RawAccess<>::oop_load(p);
1266 if (!CompressedOops::is_null(o)) {
1267 oop obj = CompressedOops::decode_not_null(o);
1268 if (_heap->is_in_young(obj) && !_scanner->is_card_dirty((HeapWord*) p)) {
1269 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1270 _message, "clean card should be dirty", __FILE__, __LINE__);
1271 }
1272 }
1273 }
1274
1275 void do_oop(narrowOop* p) override { work(p); }
1276 void do_oop(oop* p) override { work(p); }
1277 };
1278
1279 ShenandoahMarkingContext* ShenandoahVerifier::get_marking_context_for_old() {
1280 shenandoah_assert_generations_reconciled();
1281 if (_heap->old_generation()->is_mark_complete() || _heap->gc_generation()->is_global()) {
1282 return _heap->complete_marking_context();
1283 }
1284 return nullptr;
1285 }
1286
1287 template<typename Scanner>
1288 void ShenandoahVerifier::help_verify_region_rem_set(Scanner* scanner, ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx,
1289 HeapWord* registration_watermark, const char* message) {
1290 ShenandoahVerifyRemSetClosure<Scanner> check_interesting_pointers(scanner, message);
1291 HeapWord* from = r->bottom();
1292 HeapWord* obj_addr = from;
1293 if (r->is_humongous_start()) {
1294 oop obj = cast_to_oop(obj_addr);
1295 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1296 // For humongous objects, the typical object is an array, so the following checks may be overkill
1297 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1298 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1299 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1300 obj->oop_iterate(&check_interesting_pointers);
1301 }
1302 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1303 }
1304 // else, this humongous object is not live so no need to verify its internal pointers
1305
1306 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1307 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1308 "object not properly registered", __FILE__, __LINE__);
1309 }
1310 } else if (!r->is_humongous()) {
1311 HeapWord* top = r->top();
1312 while (obj_addr < top) {
1313 oop obj = cast_to_oop(obj_addr);
1314 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1315 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1316 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1317 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1318 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1319 obj->oop_iterate(&check_interesting_pointers);
1320 }
1321 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1322
1323 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1324 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1325 "object not properly registered", __FILE__, __LINE__);
1326 }
1327 obj_addr += obj->size();
1328 } else {
1329 // This object is not live so we don't verify dirty cards contained therein
1330 HeapWord* tams = ctx->top_at_mark_start(r);
1331 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1332 }
1333 }
1334 }
1335 }
1336
1337 class ShenandoahWriteTableScanner {
1338 private:
1339 ShenandoahScanRemembered* _scanner;
1340 public:
1341 explicit ShenandoahWriteTableScanner(ShenandoahScanRemembered* scanner) : _scanner(scanner) {}
1342
1343 bool is_card_dirty(HeapWord* obj_addr) {
1344 return _scanner->is_write_card_dirty(obj_addr);
1345 }
1346
1347 bool verify_registration(HeapWord* obj_addr, ShenandoahMarkingContext* ctx) {
1348 return _scanner->verify_registration(obj_addr, ctx);
1349 }
1350 };
1351
1352 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1353 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1354 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1355 // restore them until the start of evacuation.
1356 void ShenandoahVerifier::verify_rem_set_before_mark() {
1357 shenandoah_assert_safepoint();
1358 shenandoah_assert_generational();
1359
1360 ShenandoahMarkingContext* ctx = get_marking_context_for_old();
1361 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1362
1363 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1364
1365 ShenandoahScanRemembered* scanner = old_generation->card_scan();
1366 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1367 ShenandoahHeapRegion* r = _heap->get_region(i);
1368 if (r->is_old() && r->is_active()) {
1369 help_verify_region_rem_set(scanner, r, ctx, r->end(), "Verify init-mark remembered set violation");
1370 }
1371 }
1372 }
1373
1374 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1375 shenandoah_assert_safepoint();
1376 shenandoah_assert_generational();
1377
1378 ShenandoahWriteTableScanner scanner(ShenandoahGenerationalHeap::heap()->old_generation()->card_scan());
1379 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1380 ShenandoahHeapRegion* r = _heap->get_region(i);
1381 if (r->is_old() && !r->is_cset()) {
1382 help_verify_region_rem_set(&scanner, r, nullptr, r->top(), "Remembered set violation at end of Full GC");
1383 }
1384 }
1385 }
1386
1387 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1388 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1389 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1390 // all PLABS are retired immediately before the start of update refs.
1391 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1392 shenandoah_assert_safepoint();
1393 shenandoah_assert_generational();
1394
1395 ShenandoahMarkingContext* ctx = get_marking_context_for_old();
1396 ShenandoahWriteTableScanner scanner(_heap->old_generation()->card_scan());
1397 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1398 ShenandoahHeapRegion* r = _heap->get_region(i);
1399 if (r->is_old() && !r->is_cset()) {
1400 help_verify_region_rem_set(&scanner, r, ctx, r->get_update_watermark(), "Remembered set violation at init-update-references");
1401 }
1402 }
1403 }
1404
1405 void ShenandoahVerifier::verify_before_rebuilding_free_set() {
1406 ShenandoahGenerationStatsClosure cl;
1407 _heap->heap_region_iterate(&cl);
1408
1409 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
1410 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
1411 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
1412 }