1 /*
2 * Copyright (c) 2017, 2025, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "gc/shared/tlab_globals.hpp"
28 #include "gc/shenandoah/shenandoahAsserts.hpp"
29 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
30 #include "gc/shenandoah/shenandoahGeneration.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
33 #include "gc/shenandoah/shenandoahOldGeneration.hpp"
34 #include "gc/shenandoah/shenandoahPhaseTimings.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 check(ShenandoahAsserts::_safe_unknown, obj, os::is_readable_pointer(obj),
153 "oop must be accessible");
154
155 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
156
157 narrowKlass nk = 0;
158 const Klass* obj_klass = nullptr;
159 const bool klass_valid = ShenandoahAsserts::extract_klass_safely(obj, nk, obj_klass);
160
161 check(ShenandoahAsserts::_safe_unknown, obj, klass_valid,
162 "Object klass pointer unreadable or invalid");
163
164 // Verify that obj is not in dead space:
165 {
166 // Do this before touching obj->size()
167 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
168 "Object klass pointer must go to metaspace");
169
170 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
171 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
172 "Object start should be within the region");
173
174 if (!obj_reg->is_humongous()) {
175 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + ShenandoahForwarding::size(obj)) <= obj_reg->top(),
176 "Object end should be within the region");
177 } else {
178 size_t humongous_start = obj_reg->index();
179 size_t humongous_end = humongous_start + (ShenandoahForwarding::size(obj) >> ShenandoahHeapRegion::region_size_words_shift());
180 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
181 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
182 "Humongous object is in continuation that fits it");
183 }
184 }
185
186 // ------------ obj is safe at this point --------------
187
188 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
189 "Object should be in active region");
190
191 switch (_options._verify_liveness) {
192 case ShenandoahVerifier::_verify_liveness_disable:
193 // skip
194 break;
195 case ShenandoahVerifier::_verify_liveness_complete:
196 Atomic::add(&_ld[obj_reg->index()], (uint) ShenandoahForwarding::size(obj), memory_order_relaxed);
197 // fallthrough for fast failure for un-live regions:
198 case ShenandoahVerifier::_verify_liveness_conservative:
199 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
200 (obj_reg->is_old() && _heap->gc_generation()->is_young()),
201 "Object must belong to region with live data");
202 shenandoah_assert_generations_reconciled();
203 break;
204 default:
205 assert(false, "Unhandled liveness verification");
206 }
207 }
208
209 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
210
211 ShenandoahHeapRegion* fwd_reg = nullptr;
212
213 if (obj != fwd) {
214 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in_reserved(fwd),
215 "Forwardee must be in heap bounds");
216 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
217 "Forwardee is set");
218 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
219 "Forwardee must be aligned");
220
221 // Do this before touching fwd->size()
222 Klass* fwd_klass = fwd->klass_or_null();
223 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != nullptr,
224 "Forwardee klass pointer should not be null");
225 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
226 "Forwardee klass pointer must go to metaspace");
227 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
228 "Forwardee klass pointer must go to metaspace");
229
230 fwd_reg = _heap->heap_region_containing(fwd);
231
232 check(ShenandoahAsserts::_safe_oop, obj, fwd_reg->is_active(),
233 "Forwardee should be in active region");
234
235 // Verify that forwardee is not in the dead space:
236 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
237 "Should have no humongous forwardees");
238
239 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
240 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
241 "Forwardee start should be within the region");
242 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + ShenandoahForwarding::size(fwd)) <= fwd_reg->top(),
243 "Forwardee end should be within the region");
244
245 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
246 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
247 "Double forwarding");
248 } else {
249 fwd_reg = obj_reg;
250 }
251
252 // Do additional checks for special objects: their fields can hold metadata as well.
253 // We want to check class loading/unloading did not corrupt them. We can only reasonably
254 // trust the forwarded objects, as the from-space object can have the klasses effectively
255 // dead.
256
257 if (obj_klass == vmClasses::Class_klass()) {
258 const Metadata* klass = fwd->metadata_field(java_lang_Class::klass_offset());
259 check(ShenandoahAsserts::_safe_oop, obj,
260 klass == nullptr || Metaspace::contains(klass),
261 "Mirrored instance class should point to Metaspace");
262
263 const Metadata* array_klass = obj->metadata_field(java_lang_Class::array_klass_offset());
264 check(ShenandoahAsserts::_safe_oop, obj,
265 array_klass == nullptr || Metaspace::contains(array_klass),
266 "Mirrored array class should point to Metaspace");
267 }
268
269 // ------------ obj and fwd are safe at this point --------------
270 switch (_options._verify_marked) {
271 case ShenandoahVerifier::_verify_marked_disable:
272 // skip
273 break;
274 case ShenandoahVerifier::_verify_marked_incomplete:
275 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),
276 "Must be marked in incomplete bitmap");
277 break;
278 case ShenandoahVerifier::_verify_marked_complete:
279 check(ShenandoahAsserts::_safe_all, obj, _heap->gc_generation()->complete_marking_context()->is_marked(obj),
280 "Must be marked in complete bitmap");
281 break;
282 case ShenandoahVerifier::_verify_marked_complete_except_references:
283 case ShenandoahVerifier::_verify_marked_complete_satb_empty:
284 check(ShenandoahAsserts::_safe_all, obj, _heap->gc_generation()->complete_marking_context()->is_marked(obj),
285 "Must be marked in complete bitmap, except j.l.r.Reference referents");
286 break;
287 default:
288 assert(false, "Unhandled mark verification");
289 }
290
291 switch (_options._verify_forwarded) {
292 case ShenandoahVerifier::_verify_forwarded_disable:
293 // skip
294 break;
295 case ShenandoahVerifier::_verify_forwarded_none: {
296 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
297 "Should not be forwarded");
298 break;
299 }
300 case ShenandoahVerifier::_verify_forwarded_allow: {
301 if (obj != fwd) {
302 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
303 "Forwardee should be in another region");
304 }
305 break;
306 }
307 default:
308 assert(false, "Unhandled forwarding verification");
309 }
310
311 switch (_options._verify_cset) {
312 case ShenandoahVerifier::_verify_cset_disable:
313 // skip
314 break;
315 case ShenandoahVerifier::_verify_cset_none:
316 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
317 "Should not have references to collection set");
318 break;
319 case ShenandoahVerifier::_verify_cset_forwarded:
320 if (_heap->in_collection_set(obj)) {
321 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
322 "Object in collection set, should have forwardee");
323 }
324 break;
325 default:
326 assert(false, "Unhandled cset verification");
327 }
328
329 }
330
331 public:
332 /**
333 * Verify object with known interior reference.
334 * @param p interior reference where the object is referenced from; can be off-heap
335 * @param obj verified object
336 */
337 template <class T>
338 void verify_oop_at(T* p, oop obj) {
339 _interior_loc = p;
340 verify_oop(obj);
341 _interior_loc = nullptr;
342 }
343
344 /**
345 * Verify object without known interior reference.
346 * Useful when picking up the object at known offset in heap,
347 * but without knowing what objects reference it.
348 * @param obj verified object
349 */
350 void verify_oop_standalone(oop obj) {
351 _interior_loc = nullptr;
352 verify_oop(obj);
353 _interior_loc = nullptr;
354 }
355
356 /**
357 * Verify oop fields from this object.
358 * @param obj host object for verified fields
359 */
360 void verify_oops_from(oop obj) {
361 _loc = obj;
362 // oop_iterate() can not deal with forwarded objects, because
363 // it needs to load klass(), which may be overridden by the
364 // forwarding pointer.
365 oop fwd = ShenandoahForwarding::get_forwardee_raw(obj);
366 fwd->oop_iterate(this);
367 _loc = nullptr;
368 }
369
370 void do_oop(oop* p) override { do_oop_work(p); }
371 void do_oop(narrowOop* p) override { do_oop_work(p); }
372 };
373
374 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
375 // a subset (e.g. the young generation or old generation) of the total heap.
376 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
377 private:
378 size_t _used, _committed, _garbage, _regions, _humongous_waste, _trashed_regions;
379 public:
380 ShenandoahCalculateRegionStatsClosure() :
381 _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0), _trashed_regions(0) {};
382
383 void heap_region_do(ShenandoahHeapRegion* r) override {
384 _used += r->used();
385 _garbage += r->garbage();
386 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
387 if (r->is_humongous()) {
388 _humongous_waste += r->free();
389 }
390 if (r->is_trash()) {
391 _trashed_regions++;
392 }
393 _regions++;
394 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding %zu for %s Region %zu, yielding: %zu",
395 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
396 }
397
398 size_t used() const { return _used; }
399 size_t committed() const { return _committed; }
400 size_t garbage() const { return _garbage; }
401 size_t regions() const { return _regions; }
402 size_t waste() const { return _humongous_waste; }
403
404 // span is the total memory affiliated with these stats (some of which is in use and other is available)
405 size_t span() const { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
406 size_t non_trashed_span() const { return (_regions - _trashed_regions) * ShenandoahHeapRegion::region_size_bytes(); }
407 };
408
409 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
410 public:
411 ShenandoahCalculateRegionStatsClosure old;
412 ShenandoahCalculateRegionStatsClosure young;
413 ShenandoahCalculateRegionStatsClosure global;
414
415 void heap_region_do(ShenandoahHeapRegion* r) override {
416 switch (r->affiliation()) {
417 case FREE:
418 return;
419 case YOUNG_GENERATION:
420 young.heap_region_do(r);
421 global.heap_region_do(r);
422 break;
423 case OLD_GENERATION:
424 old.heap_region_do(r);
425 global.heap_region_do(r);
426 break;
427 default:
428 ShouldNotReachHere();
429 }
430 }
431
432 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
433 log_debug(gc)("Safepoint verification: %s verified usage: %zu%s, recorded usage: %zu%s",
434 generation->name(),
435 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
436 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
437 }
438
439 static void validate_usage(const bool adjust_for_padding,
440 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
441 ShenandoahHeap* heap = ShenandoahHeap::heap();
442 size_t generation_used = generation->used();
443 size_t generation_used_regions = generation->used_regions();
444 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
445 size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
446 generation_used += pad;
447 }
448
449 guarantee(stats.used() == generation_used,
450 "%s: generation (%s) used size must be consistent: generation-used: " PROPERFMT ", regions-used: " PROPERFMT,
451 label, generation->name(), PROPERFMTARGS(generation_used), PROPERFMTARGS(stats.used()));
452
453 guarantee(stats.regions() == generation_used_regions,
454 "%s: generation (%s) used regions (%zu) must equal regions that are in use (%zu)",
455 label, generation->name(), generation->used_regions(), stats.regions());
456
457 size_t generation_capacity = generation->max_capacity();
458 guarantee(stats.non_trashed_span() <= generation_capacity,
459 "%s: generation (%s) size spanned by regions (%zu) * region size (" PROPERFMT
460 ") must not exceed current capacity (" PROPERFMT ")",
461 label, generation->name(), stats.regions(), PROPERFMTARGS(ShenandoahHeapRegion::region_size_bytes()),
462 PROPERFMTARGS(generation_capacity));
463
464 size_t humongous_waste = generation->get_humongous_waste();
465 guarantee(stats.waste() == humongous_waste,
466 "%s: generation (%s) humongous waste must be consistent: generation: " PROPERFMT ", regions: " PROPERFMT,
467 label, generation->name(), PROPERFMTARGS(humongous_waste), PROPERFMTARGS(stats.waste()));
468 }
469 };
470
471 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
472 private:
473 ShenandoahHeap* _heap;
474 const char* _phase;
475 ShenandoahVerifier::VerifyRegions _regions;
476 public:
477 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
478 _heap(ShenandoahHeap::heap()),
479 _phase(phase),
480 _regions(regions) {};
481
482 void print_failure(ShenandoahHeapRegion* r, const char* label) {
483 ResourceMark rm;
484
485 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
486
487 stringStream ss;
488 r->print_on(&ss);
489 msg.append("%s", ss.as_string());
490
491 report_vm_error(__FILE__, __LINE__, msg.buffer());
492 }
493
494 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
495 if (!test) {
496 print_failure(r, msg);
497 }
498 }
499
500 void heap_region_do(ShenandoahHeapRegion* r) override {
501 switch (_regions) {
502 case ShenandoahVerifier::_verify_regions_disable:
503 break;
504 case ShenandoahVerifier::_verify_regions_notrash:
505 verify(r, !r->is_trash(),
506 "Should not have trash regions");
507 break;
508 case ShenandoahVerifier::_verify_regions_nocset:
509 verify(r, !r->is_cset(),
510 "Should not have cset regions");
511 break;
512 case ShenandoahVerifier::_verify_regions_notrash_nocset:
513 verify(r, !r->is_trash(),
514 "Should not have trash regions");
515 verify(r, !r->is_cset(),
516 "Should not have cset regions");
517 break;
518 default:
519 ShouldNotReachHere();
520 }
521
522 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
523 "Capacity should match region size");
524
525 verify(r, r->bottom() <= r->top(),
526 "Region top should not be less than bottom");
527
528 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
529 "Region TAMS should not be less than bottom");
530
531 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
532 "Complete TAMS should not be larger than top");
533
534 verify(r, r->get_live_data_bytes() <= r->capacity(),
535 "Live data cannot be larger than capacity");
536
537 verify(r, r->garbage() <= r->capacity(),
538 "Garbage cannot be larger than capacity");
539
540 verify(r, r->used() <= r->capacity(),
541 "Used cannot be larger than capacity");
542
543 verify(r, r->get_shared_allocs() <= r->capacity(),
544 "Shared alloc count should not be larger than capacity");
545
546 verify(r, r->get_tlab_allocs() <= r->capacity(),
547 "TLAB alloc count should not be larger than capacity");
548
549 verify(r, r->get_gclab_allocs() <= r->capacity(),
550 "GCLAB alloc count should not be larger than capacity");
551
552 verify(r, r->get_plab_allocs() <= r->capacity(),
553 "PLAB alloc count should not be larger than capacity");
554
555 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
556 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
557
558 verify(r, !r->is_empty() || !r->has_live(),
559 "Empty regions should not have live data");
560
561 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
562 "Transitional: region flags and collection set agree");
563 }
564 };
565
566 class ShenandoahVerifierReachableTask : public WorkerTask {
567 private:
568 const char* _label;
569 ShenandoahVerifier::VerifyOptions _options;
570 ShenandoahHeap* _heap;
571 ShenandoahLivenessData* _ld;
572 MarkBitMap* _bitmap;
573 volatile size_t _processed;
574
575 public:
576 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
577 ShenandoahLivenessData* ld,
578 const char* label,
579 ShenandoahVerifier::VerifyOptions options) :
580 WorkerTask("Shenandoah Verifier Reachable Objects"),
581 _label(label),
582 _options(options),
583 _heap(ShenandoahHeap::heap()),
584 _ld(ld),
585 _bitmap(bitmap),
586 _processed(0) {};
587
588 size_t processed() const {
589 return _processed;
590 }
591
592 void work(uint worker_id) override {
593 ResourceMark rm;
594 ShenandoahVerifierStack stack;
595
596 // On level 2, we need to only check the roots once.
597 // On level 3, we want to check the roots, and seed the local stack.
598 // It is a lesser evil to accept multiple root scans at level 3, because
599 // extended parallelism would buy us out.
600 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
601 || (ShenandoahVerifyLevel >= 3)) {
602 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
603 ShenandoahMessageBuffer("%s, Roots", _label),
604 _options);
605 if (_heap->unload_classes()) {
606 ShenandoahRootVerifier::strong_roots_do(&cl);
607 } else {
608 ShenandoahRootVerifier::roots_do(&cl);
609 }
610 }
611
612 size_t processed = 0;
613
614 if (ShenandoahVerifyLevel >= 3) {
615 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
616 ShenandoahMessageBuffer("%s, Reachable", _label),
617 _options);
618 while (!stack.is_empty()) {
619 processed++;
620 ShenandoahVerifierTask task = stack.pop();
621 cl.verify_oops_from(task.obj());
622 }
623 }
624
625 Atomic::add(&_processed, processed, memory_order_relaxed);
626 }
627 };
628
629 class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
630 public:
631 void do_thread(Thread* thread) override {
632 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
633 if (!queue.is_empty()) {
634 fatal("All SATB buffers should have been flushed during mark");
635 }
636 }
637 };
638
639 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
640 private:
641 const char* _label;
642 ShenandoahVerifier::VerifyOptions _options;
643 ShenandoahHeap *_heap;
644 MarkBitMap* _bitmap;
645 ShenandoahLivenessData* _ld;
646 volatile size_t _claimed;
647 volatile size_t _processed;
648 ShenandoahGeneration* _generation;
649
650 public:
651 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
652 ShenandoahLivenessData* ld,
653 const char* label,
654 ShenandoahVerifier::VerifyOptions options) :
655 WorkerTask("Shenandoah Verifier Marked Objects"),
656 _label(label),
657 _options(options),
658 _heap(ShenandoahHeap::heap()),
659 _bitmap(bitmap),
660 _ld(ld),
661 _claimed(0),
662 _processed(0),
663 _generation(nullptr) {
664 if (_heap->mode()->is_generational()) {
665 _generation = _heap->gc_generation();
666 assert(_generation != nullptr, "Expected active generation in this mode.");
667 shenandoah_assert_generations_reconciled();
668 }
669 };
670
671 size_t processed() {
672 return Atomic::load(&_processed);
673 }
674
675 void work(uint worker_id) override {
676 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
677 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
678 Threads::threads_do(&verify_satb);
679 }
680
681 ShenandoahVerifierStack stack;
682 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
683 ShenandoahMessageBuffer("%s, Marked", _label),
684 _options);
685
686 while (true) {
687 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
688 if (v < _heap->num_regions()) {
689 ShenandoahHeapRegion* r = _heap->get_region(v);
690 if (!in_generation(r)) {
691 continue;
692 }
693
694 if (!r->is_humongous() && !r->is_trash()) {
695 work_regular(r, stack, cl);
696 } else if (r->is_humongous_start()) {
697 work_humongous(r, stack, cl);
698 }
699 } else {
700 break;
701 }
702 }
703 }
704
705 bool in_generation(ShenandoahHeapRegion* r) {
706 return _generation == nullptr || _generation->contains(r);
707 }
708
709 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
710 size_t processed = 0;
711 HeapWord* obj = r->bottom();
712 if (_heap->gc_generation()->complete_marking_context()->is_marked(cast_to_oop(obj))) {
713 verify_and_follow(obj, stack, cl, &processed);
714 }
715 Atomic::add(&_processed, processed, memory_order_relaxed);
716 }
717
718 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
719 size_t processed = 0;
720 ShenandoahMarkingContext* ctx = _heap->gc_generation()->complete_marking_context();
721 HeapWord* tams = ctx->top_at_mark_start(r);
722
723 // Bitmaps, before TAMS
724 if (tams > r->bottom()) {
725 HeapWord* start = r->bottom();
726 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
727
728 while (addr < tams) {
729 verify_and_follow(addr, stack, cl, &processed);
730 addr += 1;
731 if (addr < tams) {
732 addr = ctx->get_next_marked_addr(addr, tams);
733 }
734 }
735 }
736
737 // Size-based, after TAMS
738 {
739 HeapWord* limit = r->top();
740 HeapWord* addr = tams;
741
742 while (addr < limit) {
743 verify_and_follow(addr, stack, cl, &processed);
744 addr += ShenandoahForwarding::size(cast_to_oop(addr));
745 }
746 }
747
748 Atomic::add(&_processed, processed, memory_order_relaxed);
749 }
750
751 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
752 if (!_bitmap->par_mark(addr)) return;
753
754 // Verify the object itself:
755 oop obj = cast_to_oop(addr);
756 cl.verify_oop_standalone(obj);
757
758 // Verify everything reachable from that object too, hopefully realizing
759 // everything was already marked, and never touching further:
760 if (!is_instance_ref_klass(ShenandoahForwarding::klass(obj))) {
761 cl.verify_oops_from(obj);
762 (*processed)++;
763 }
764 while (!stack.is_empty()) {
765 ShenandoahVerifierTask task = stack.pop();
766 cl.verify_oops_from(task.obj());
767 (*processed)++;
768 }
769 }
770 };
771
772 class VerifyThreadGCState : public ThreadClosure {
773 private:
774 const char* const _label;
775 char const _expected;
776
777 public:
778 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
779 void do_thread(Thread* t) override {
780 char actual = ShenandoahThreadLocalData::gc_state(t);
781 if (!verify_gc_state(actual, _expected)) {
782 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
783 }
784 }
785
786 static bool verify_gc_state(char actual, char expected) {
787 // Old generation marking is allowed in all states.
788 if (ShenandoahHeap::heap()->mode()->is_generational()) {
789 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
790 } else {
791 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
792 return (actual == expected);
793 }
794 }
795 };
796
797 void ShenandoahVerifier::verify_at_safepoint(const char* label,
798 VerifyRememberedSet remembered,
799 VerifyForwarded forwarded,
800 VerifyMarked marked,
801 VerifyCollectionSet cset,
802 VerifyLiveness liveness,
803 VerifyRegions regions,
804 VerifySize sizeness,
805 VerifyGCState gcstate) {
806 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
807 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
808
809 ShenandoahHeap::heap()->propagate_gc_state_to_all_threads();
810
811 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
812 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
813
814 log_info(gc,start)("Verify %s, Level %zd", label, ShenandoahVerifyLevel);
815
816 // GC state checks
817 {
818 char expected = -1;
819 bool enabled;
820 switch (gcstate) {
821 case _verify_gcstate_disable:
822 enabled = false;
823 break;
824 case _verify_gcstate_forwarded:
825 enabled = true;
826 expected = ShenandoahHeap::HAS_FORWARDED;
827 break;
828 case _verify_gcstate_updating:
829 enabled = true;
830 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATE_REFS;
831 break;
832 case _verify_gcstate_stable:
833 enabled = true;
834 expected = ShenandoahHeap::STABLE;
835 break;
836 case _verify_gcstate_stable_weakroots:
837 enabled = true;
838 expected = ShenandoahHeap::STABLE;
839 if (!_heap->is_stw_gc_in_progress()) {
840 // Only concurrent GC sets this.
841 expected |= ShenandoahHeap::WEAK_ROOTS;
842 }
843 break;
844 default:
845 enabled = false;
846 assert(false, "Unhandled gc-state verification");
847 }
848
849 if (enabled) {
850 char actual = _heap->gc_state();
851
852 bool is_marking = (actual & ShenandoahHeap::MARKING);
853 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
854 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
855
856 // Old generation marking is allowed in all states.
857 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
858 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
859 }
860
861 VerifyThreadGCState vtgcs(label, expected);
862 Threads::java_threads_do(&vtgcs);
863 }
864 }
865
866 // Deactivate barriers temporarily: Verifier wants plain heap accesses
867 ShenandoahGCStateResetter resetter;
868
869 // Heap size checks
870 {
871 ShenandoahHeapLocker lock(_heap->lock());
872
873 ShenandoahCalculateRegionStatsClosure cl;
874 _heap->heap_region_iterate(&cl);
875 size_t heap_used;
876 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
877 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
878 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
879 } else if (sizeness != _verify_size_disable) {
880 heap_used = _heap->used();
881 }
882 if (sizeness != _verify_size_disable) {
883 guarantee(cl.used() == heap_used,
884 "%s: heap used size must be consistent: heap-used = %zu%s, regions-used = %zu%s",
885 label,
886 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
887 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
888 }
889 size_t heap_committed = _heap->committed();
890 guarantee(cl.committed() == heap_committed,
891 "%s: heap committed size must be consistent: heap-committed = %zu%s, regions-committed = %zu%s",
892 label,
893 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
894 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
895 }
896
897 log_debug(gc)("Safepoint verification finished heap usage verification");
898
899 ShenandoahGeneration* generation;
900 if (_heap->mode()->is_generational()) {
901 generation = _heap->gc_generation();
902 guarantee(generation != nullptr, "Need to know which generation to verify.");
903 shenandoah_assert_generations_reconciled();
904 } else {
905 generation = nullptr;
906 }
907
908 if (generation != nullptr) {
909 ShenandoahHeapLocker lock(_heap->lock());
910
911 switch (remembered) {
912 case _verify_remembered_disable:
913 break;
914 case _verify_remembered_before_marking:
915 log_debug(gc)("Safepoint verification of remembered set at mark");
916 verify_rem_set_before_mark();
917 break;
918 case _verify_remembered_before_updating_references:
919 log_debug(gc)("Safepoint verification of remembered set at update ref");
920 verify_rem_set_before_update_ref();
921 break;
922 case _verify_remembered_after_full_gc:
923 log_debug(gc)("Safepoint verification of remembered set after full gc");
924 verify_rem_set_after_full_gc();
925 break;
926 default:
927 fatal("Unhandled remembered set verification mode");
928 }
929
930 ShenandoahGenerationStatsClosure cl;
931 _heap->heap_region_iterate(&cl);
932
933 if (LogTarget(Debug, gc)::is_enabled()) {
934 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
935 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
936 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
937 }
938 if (sizeness == _verify_size_adjusted_for_padding) {
939 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
940 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
941 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
942 } else if (sizeness == _verify_size_exact) {
943 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
944 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
945 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
946 }
947 // else: sizeness must equal _verify_size_disable
948 }
949
950 log_debug(gc)("Safepoint verification finished remembered set verification");
951
952 // Internal heap region checks
953 if (ShenandoahVerifyLevel >= 1) {
954 ShenandoahVerifyHeapRegionClosure cl(label, regions);
955 if (generation != nullptr) {
956 generation->heap_region_iterate(&cl);
957 } else {
958 _heap->heap_region_iterate(&cl);
959 }
960 }
961
962 log_debug(gc)("Safepoint verification finished heap region closure verification");
963
964 OrderAccess::fence();
965
966 if (UseTLAB) {
967 _heap->labs_make_parsable();
968 }
969
970 // Allocate temporary bitmap for storing marking wavefront:
971 _verification_bit_map->clear();
972
973 // Allocate temporary array for storing liveness data
974 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
975 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
976
977 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
978
979 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
980 // This verifies what application can see, since it only cares about reachable objects.
981 size_t count_reachable = 0;
982 if (ShenandoahVerifyLevel >= 2) {
983 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
984 _heap->workers()->run_task(&task);
985 count_reachable = task.processed();
986 }
987
988 log_debug(gc)("Safepoint verification finished getting initial reachable set");
989
990 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
991 // not the application, can see during the region scans. There is no reason to process the objects
992 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
993 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
994 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
995 // version
996
997 size_t count_marked = 0;
998 if (ShenandoahVerifyLevel >= 4 &&
999 (marked == _verify_marked_complete ||
1000 marked == _verify_marked_complete_except_references ||
1001 marked == _verify_marked_complete_satb_empty)) {
1002 guarantee(_heap->gc_generation()->is_mark_complete(), "Marking context should be complete");
1003 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
1004 _heap->workers()->run_task(&task);
1005 count_marked = task.processed();
1006 } else {
1007 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
1008 }
1009
1010 log_debug(gc)("Safepoint verification finished walking marked objects");
1011
1012 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
1013 // marked objects.
1014
1015 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
1016 for (size_t i = 0; i < _heap->num_regions(); i++) {
1017 ShenandoahHeapRegion* r = _heap->get_region(i);
1018 if (generation != nullptr && !generation->contains(r)) {
1019 continue;
1020 }
1021
1022 juint verf_live = 0;
1023 if (r->is_humongous()) {
1024 // For humongous objects, test if start region is marked live, and if so,
1025 // all humongous regions in that chain have live data equal to their "used".
1026 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1027 if (start_live > 0) {
1028 verf_live = (juint)(r->used() / HeapWordSize);
1029 }
1030 } else {
1031 verf_live = Atomic::load(&ld[r->index()]);
1032 }
1033
1034 size_t reg_live = r->get_live_data_words();
1035 if (reg_live != verf_live) {
1036 stringStream ss;
1037 r->print_on(&ss);
1038 fatal("%s: Live data should match: region-live = %zu, verifier-live = " UINT32_FORMAT "\n%s",
1039 label, reg_live, verf_live, ss.freeze());
1040 }
1041 }
1042 }
1043
1044 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1045
1046
1047 log_info(gc)("Verify %s, Level %zd (%zu reachable, %zu marked)",
1048 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1049
1050 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1051 }
1052
1053 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1054 verify_at_safepoint(
1055 "Generic Verification",
1056 _verify_remembered_disable, // do not verify remembered set
1057 _verify_forwarded_allow, // conservatively allow forwarded
1058 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1059 _verify_cset_disable, // cset may be inconsistent
1060 _verify_liveness_disable, // no reliable liveness data
1061 _verify_regions_disable, // no reliable region data
1062 _verify_size_exact, // expect generation and heap sizes to match exactly
1063 _verify_gcstate_disable // no data about gcstate
1064 );
1065 }
1066
1067 void ShenandoahVerifier::verify_before_concmark() {
1068 VerifyRememberedSet verify_remembered_set = _verify_remembered_before_marking;
1069 if (_heap->mode()->is_generational() &&
1070 !_heap->old_generation()->is_mark_complete()) {
1071 // Before marking in generational mode, remembered set can't be verified w/o complete old marking.
1072 verify_remembered_set = _verify_remembered_disable;
1073 }
1074 verify_at_safepoint(
1075 "Before Mark",
1076 verify_remembered_set,
1077 // verify read-only remembered set from bottom() to top()
1078 _verify_forwarded_none, // UR should have fixed up
1079 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1080 _verify_cset_none, // UR should have fixed this
1081 _verify_liveness_disable, // no reliable liveness data
1082 _verify_regions_notrash, // no trash regions
1083 _verify_size_exact, // expect generation and heap sizes to match exactly
1084 _verify_gcstate_stable // there are no forwarded objects
1085 );
1086 }
1087
1088 void ShenandoahVerifier::verify_after_concmark() {
1089 verify_at_safepoint(
1090 "After Mark",
1091 _verify_remembered_disable, // do not verify remembered set
1092 _verify_forwarded_none, // no forwarded references
1093 _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
1094 _verify_cset_none, // no references to cset anymore
1095 _verify_liveness_complete, // liveness data must be complete here
1096 _verify_regions_disable, // trash regions not yet recycled
1097 _verify_size_exact, // expect generation and heap sizes to match exactly
1098 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1099 );
1100 }
1101
1102 void ShenandoahVerifier::verify_after_concmark_with_promotions() {
1103 verify_at_safepoint(
1104 "After Mark",
1105 _verify_remembered_disable, // do not verify remembered set
1106 _verify_forwarded_none, // no forwarded references
1107 _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
1108 _verify_cset_none, // no references to cset anymore
1109 _verify_liveness_complete, // liveness data must be complete here
1110 _verify_regions_disable, // trash regions not yet recycled
1111 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1112 // for promote in place padding
1113 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1114 );
1115 }
1116
1117 void ShenandoahVerifier::verify_before_evacuation() {
1118 verify_at_safepoint(
1119 "Before Evacuation",
1120 _verify_remembered_disable, // do not verify remembered set
1121 _verify_forwarded_none, // no forwarded references
1122 _verify_marked_complete_except_references, // walk over marked objects too
1123 _verify_cset_disable, // non-forwarded references to cset expected
1124 _verify_liveness_complete, // liveness data must be complete here
1125 _verify_regions_disable, // trash regions not yet recycled
1126 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1127 // for promote in place padding
1128 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1129 );
1130 }
1131
1132 void ShenandoahVerifier::verify_before_update_refs() {
1133 VerifyRememberedSet verify_remembered_set = _verify_remembered_before_updating_references;
1134 if (_heap->mode()->is_generational() &&
1135 !_heap->old_generation()->is_mark_complete()) {
1136 verify_remembered_set = _verify_remembered_disable;
1137 }
1138 verify_at_safepoint(
1139 "Before Updating References",
1140 verify_remembered_set, // verify read-write remembered set
1141 _verify_forwarded_allow, // forwarded references allowed
1142 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1143 _verify_cset_forwarded, // all cset refs are fully forwarded
1144 _verify_liveness_disable, // no reliable liveness data anymore
1145 _verify_regions_notrash, // trash regions have been recycled already
1146 _verify_size_exact, // expect generation and heap sizes to match exactly
1147 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1148 );
1149 }
1150
1151 // We have not yet cleanup (reclaimed) the collection set
1152 void ShenandoahVerifier::verify_after_update_refs() {
1153 verify_at_safepoint(
1154 "After Updating References",
1155 _verify_remembered_disable, // do not verify remembered set
1156 _verify_forwarded_none, // no forwarded references
1157 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1158 _verify_cset_none, // no cset references, all updated
1159 _verify_liveness_disable, // no reliable liveness data anymore
1160 _verify_regions_nocset, // no cset regions, trash regions have appeared
1161 _verify_size_exact, // expect generation and heap sizes to match exactly
1162 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1163 );
1164 }
1165
1166 void ShenandoahVerifier::verify_after_degenerated() {
1167 verify_at_safepoint(
1168 "After Degenerated GC",
1169 _verify_remembered_disable, // do not verify remembered set
1170 _verify_forwarded_none, // all objects are non-forwarded
1171 _verify_marked_complete, // all objects are marked in complete bitmap
1172 _verify_cset_none, // no cset references
1173 _verify_liveness_disable, // no reliable liveness data anymore
1174 _verify_regions_notrash_nocset, // no trash, no cset
1175 _verify_size_exact, // expect generation and heap sizes to match exactly
1176 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1177 );
1178 }
1179
1180 void ShenandoahVerifier::verify_before_fullgc() {
1181 verify_at_safepoint(
1182 "Before Full GC",
1183 _verify_remembered_disable, // do not verify remembered set
1184 _verify_forwarded_allow, // can have forwarded objects
1185 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1186 _verify_cset_disable, // cset might be foobared
1187 _verify_liveness_disable, // no reliable liveness data anymore
1188 _verify_regions_disable, // no reliable region data here
1189 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1190 _verify_gcstate_disable // no reliable gcstate data
1191 );
1192 }
1193
1194 void ShenandoahVerifier::verify_after_fullgc() {
1195 verify_at_safepoint(
1196 "After Full GC",
1197 _verify_remembered_after_full_gc, // verify read-write remembered set
1198 _verify_forwarded_none, // all objects are non-forwarded
1199 _verify_marked_incomplete, // all objects are marked in incomplete bitmap
1200 _verify_cset_none, // no cset references
1201 _verify_liveness_disable, // no reliable liveness data anymore
1202 _verify_regions_notrash_nocset, // no trash, no cset
1203 _verify_size_exact, // expect generation and heap sizes to match exactly
1204 _verify_gcstate_stable // full gc cleaned up everything
1205 );
1206 }
1207
1208 class ShenandoahVerifyNoForwarded : public BasicOopIterateClosure {
1209 private:
1210 template <class T>
1211 void do_oop_work(T* p) {
1212 T o = RawAccess<>::oop_load(p);
1213 if (!CompressedOops::is_null(o)) {
1214 oop obj = CompressedOops::decode_not_null(o);
1215 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1216 if (obj != fwd) {
1217 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1218 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1219 }
1220 }
1221 }
1222
1223 public:
1224 void do_oop(narrowOop* p) { do_oop_work(p); }
1225 void do_oop(oop* p) { do_oop_work(p); }
1226 };
1227
1228 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1229 private:
1230 template <class T>
1231 void do_oop_work(T* p) {
1232 T o = RawAccess<>::oop_load(p);
1233 if (!CompressedOops::is_null(o)) {
1234 oop obj = CompressedOops::decode_not_null(o);
1235 ShenandoahHeap* heap = ShenandoahHeap::heap();
1236
1237 if (!heap->marking_context()->is_marked_or_old(obj)) {
1238 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1239 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1240 }
1241
1242 if (heap->in_collection_set(obj)) {
1243 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1244 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1245 }
1246
1247 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1248 if (obj != fwd) {
1249 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1250 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1251 }
1252 }
1253 }
1254
1255 public:
1256 void do_oop(narrowOop* p) override { do_oop_work(p); }
1257 void do_oop(oop* p) override { do_oop_work(p); }
1258 };
1259
1260 void ShenandoahVerifier::verify_roots_in_to_space() {
1261 ShenandoahVerifyInToSpaceClosure cl;
1262 ShenandoahRootVerifier::roots_do(&cl);
1263 }
1264
1265 void ShenandoahVerifier::verify_roots_no_forwarded() {
1266 ShenandoahVerifyNoForwarded cl;
1267 ShenandoahRootVerifier::roots_do(&cl);
1268 }
1269
1270 template<typename Scanner>
1271 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1272 protected:
1273 ShenandoahGenerationalHeap* const _heap;
1274 Scanner* const _scanner;
1275 const char* _message;
1276
1277 public:
1278 // Argument distinguishes between initial mark or start of update refs verification.
1279 explicit ShenandoahVerifyRemSetClosure(Scanner* scanner, const char* message) :
1280 _heap(ShenandoahGenerationalHeap::heap()),
1281 _scanner(scanner),
1282 _message(message) {}
1283
1284 template<class T>
1285 inline void work(T* p) {
1286 T o = RawAccess<>::oop_load(p);
1287 if (!CompressedOops::is_null(o)) {
1288 oop obj = CompressedOops::decode_not_null(o);
1289 if (_heap->is_in_young(obj) && !_scanner->is_card_dirty((HeapWord*) p)) {
1290 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1291 _message, "clean card, it should be dirty.", __FILE__, __LINE__);
1292 }
1293 }
1294 }
1295
1296 void do_oop(narrowOop* p) override { work(p); }
1297 void do_oop(oop* p) override { work(p); }
1298 };
1299
1300 template<typename Scanner>
1301 void ShenandoahVerifier::help_verify_region_rem_set(Scanner* scanner, ShenandoahHeapRegion* r,
1302 HeapWord* registration_watermark, const char* message) {
1303 shenandoah_assert_generations_reconciled();
1304 ShenandoahOldGeneration* old_gen = _heap->old_generation();
1305 assert(old_gen->is_mark_complete() || old_gen->is_parsable(), "Sanity");
1306
1307 ShenandoahMarkingContext* ctx = old_gen->is_mark_complete() ? old_gen->complete_marking_context() : nullptr;
1308 ShenandoahVerifyRemSetClosure<Scanner> check_interesting_pointers(scanner, message);
1309 HeapWord* from = r->bottom();
1310 HeapWord* obj_addr = from;
1311 if (r->is_humongous_start()) {
1312 oop obj = cast_to_oop(obj_addr);
1313 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1314 // For humongous objects, the typical object is an array, so the following checks may be overkill
1315 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1316 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1317 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1318 obj->oop_iterate(&check_interesting_pointers);
1319 }
1320 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1321 }
1322 // else, this humongous object is not live so no need to verify its internal pointers
1323
1324 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1325 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1326 "object not properly registered", __FILE__, __LINE__);
1327 }
1328 } else if (!r->is_humongous()) {
1329 HeapWord* top = r->top();
1330 while (obj_addr < top) {
1331 oop obj = cast_to_oop(obj_addr);
1332 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1333 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1334 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1335 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1336 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1337 obj->oop_iterate(&check_interesting_pointers);
1338 }
1339 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1340
1341 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1342 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1343 "object not properly registered", __FILE__, __LINE__);
1344 }
1345 obj_addr += obj->size();
1346 } else {
1347 // This object is not live so we don't verify dirty cards contained therein
1348 HeapWord* tams = ctx->top_at_mark_start(r);
1349 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1350 }
1351 }
1352 }
1353 }
1354
1355 class ShenandoahWriteTableScanner {
1356 private:
1357 ShenandoahScanRemembered* _scanner;
1358 public:
1359 explicit ShenandoahWriteTableScanner(ShenandoahScanRemembered* scanner) : _scanner(scanner) {}
1360
1361 bool is_card_dirty(HeapWord* obj_addr) {
1362 return _scanner->is_write_card_dirty(obj_addr);
1363 }
1364
1365 bool verify_registration(HeapWord* obj_addr, ShenandoahMarkingContext* ctx) {
1366 return _scanner->verify_registration(obj_addr, ctx);
1367 }
1368 };
1369
1370 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1371 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1372 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1373 // restore them until the start of evacuation.
1374 void ShenandoahVerifier::verify_rem_set_before_mark() {
1375 shenandoah_assert_safepoint();
1376 shenandoah_assert_generational();
1377
1378 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1379
1380 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1381
1382 ShenandoahScanRemembered* scanner = old_generation->card_scan();
1383 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1384 ShenandoahHeapRegion* r = _heap->get_region(i);
1385 if (r->is_old() && r->is_active()) {
1386 help_verify_region_rem_set(scanner, r, r->end(), "Verify init-mark remembered set violation");
1387 }
1388 }
1389 }
1390
1391 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1392 shenandoah_assert_safepoint();
1393 shenandoah_assert_generational();
1394
1395 ShenandoahWriteTableScanner scanner(ShenandoahGenerationalHeap::heap()->old_generation()->card_scan());
1396 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1397 ShenandoahHeapRegion* r = _heap->get_region(i);
1398 if (r->is_old() && !r->is_cset()) {
1399 help_verify_region_rem_set(&scanner, r, r->top(), "Remembered set violation at end of Full GC");
1400 }
1401 }
1402 }
1403
1404 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1405 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1406 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1407 // all PLABS are retired immediately before the start of update refs.
1408 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1409 shenandoah_assert_safepoint();
1410 shenandoah_assert_generational();
1411
1412 ShenandoahWriteTableScanner scanner(_heap->old_generation()->card_scan());
1413 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1414 ShenandoahHeapRegion* r = _heap->get_region(i);
1415 if (r->is_old() && !r->is_cset()) {
1416 help_verify_region_rem_set(&scanner, r, r->get_update_watermark(), "Remembered set violation at init-update-references");
1417 }
1418 }
1419 }
1420
1421 void ShenandoahVerifier::verify_before_rebuilding_free_set() {
1422 ShenandoahGenerationStatsClosure cl;
1423 _heap->heap_region_iterate(&cl);
1424
1425 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
1426 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
1427 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
1428 }