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 ShenandoahIgnoreReferenceDiscoverer : public ReferenceDiscoverer {
60 public:
61 virtual bool discover_reference(oop obj, ReferenceType type) {
62 return true;
63 }
64 };
65
66 class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {
67 private:
68 const char* _phase;
69 ShenandoahVerifier::VerifyOptions _options;
70 ShenandoahVerifierStack* _stack;
71 ShenandoahHeap* _heap;
72 MarkBitMap* _map;
73 ShenandoahLivenessData* _ld;
74 void* _interior_loc;
75 oop _loc;
76 ShenandoahGeneration* _generation;
77
78 public:
79 ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
80 const char* phase, ShenandoahVerifier::VerifyOptions options) :
81 _phase(phase),
82 _options(options),
83 _stack(stack),
84 _heap(ShenandoahHeap::heap()),
85 _map(map),
86 _ld(ld),
87 _interior_loc(nullptr),
88 _loc(nullptr),
89 _generation(nullptr) {
90 if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
91 options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty ||
92 options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
93 set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
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 private:
104 void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
105 if (!test) {
106 ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);
107 }
108 }
109
110 template <class T>
111 void do_oop_work(T* p) {
112 T o = RawAccess<>::oop_load(p);
113 if (!CompressedOops::is_null(o)) {
114 oop obj = CompressedOops::decode_not_null(o);
115 if (is_instance_ref_klass(obj->klass())) {
116 obj = ShenandoahForwarding::get_forwardee(obj);
117 }
118 // Single threaded verification can use faster non-atomic stack and bitmap
119 // methods.
120 //
121 // For performance reasons, only fully verify non-marked field values.
122 // We are here when the host object for *p is already marked.
123
124 // TODO: We should consider specializing this closure by generation ==/!= null,
125 // to avoid in_generation check on fast path here for non-generational mode.
126 if (in_generation(obj) && _map->par_mark(obj)) {
127 verify_oop_at(p, obj);
128 _stack->push(ShenandoahVerifierTask(obj));
129 }
130 }
131 }
132
133 bool in_generation(oop obj) {
134 if (_generation == nullptr) {
135 return true;
136 }
137
138 ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
139 return _generation->contains(region);
140 }
141
142 void verify_oop(oop obj) {
143 // Perform consistency checks with gradually decreasing safety level. This guarantees
144 // that failure report would not try to touch something that was not yet verified to be
145 // safe to process.
146
147 check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),
148 "oop must be in heap");
149 check(ShenandoahAsserts::_safe_unknown, obj, is_object_aligned(obj),
150 "oop must be aligned");
151
152 ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);
153 Klass* obj_klass = obj->klass_or_null();
154
155 // Verify that obj is not in dead space:
156 {
157 // Do this before touching obj->size()
158 check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != nullptr,
159 "Object klass pointer should not be null");
160 check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),
161 "Object klass pointer must go to metaspace");
162
163 HeapWord *obj_addr = cast_from_oop<HeapWord*>(obj);
164 check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),
165 "Object start should be within the region");
166
167 if (!obj_reg->is_humongous()) {
168 check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),
169 "Object end should be within the region");
170 } else {
171 size_t humongous_start = obj_reg->index();
172 size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());
173 for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {
174 check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),
175 "Humongous object is in continuation that fits it");
176 }
177 }
178
179 // ------------ obj is safe at this point --------------
180
181 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),
182 "Object should be in active region");
183
184 switch (_options._verify_liveness) {
185 case ShenandoahVerifier::_verify_liveness_disable:
186 // skip
187 break;
188 case ShenandoahVerifier::_verify_liveness_complete:
189 Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
190 // fallthrough for fast failure for un-live regions:
191 case ShenandoahVerifier::_verify_liveness_conservative:
192 check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
193 (obj_reg->is_old() && _heap->gc_generation()->is_young()),
194 "Object must belong to region with live data");
195 shenandoah_assert_generations_reconciled();
196 break;
197 default:
198 assert(false, "Unhandled liveness verification");
199 }
200 }
201
202 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
203
204 ShenandoahHeapRegion* fwd_reg = nullptr;
205
206 if (obj != fwd) {
207 check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),
208 "Forwardee must be in heap");
209 check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),
210 "Forwardee is set");
211 check(ShenandoahAsserts::_safe_oop, obj, is_object_aligned(fwd),
212 "Forwardee must be aligned");
213
214 // Do this before touching fwd->size()
215 Klass* fwd_klass = fwd->klass_or_null();
216 check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != nullptr,
217 "Forwardee klass pointer should not be null");
218 check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),
219 "Forwardee klass pointer must go to metaspace");
220 check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,
221 "Forwardee klass pointer must go to metaspace");
222
223 fwd_reg = _heap->heap_region_containing(fwd);
224
225 // Verify that forwardee is not in the dead space:
226 check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),
227 "Should have no humongous forwardees");
228
229 HeapWord *fwd_addr = cast_from_oop<HeapWord *>(fwd);
230 check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),
231 "Forwardee start should be within the region");
232 check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),
233 "Forwardee end should be within the region");
234
235 oop fwd2 = ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);
236 check(ShenandoahAsserts::_safe_oop, obj, (fwd == fwd2),
237 "Double forwarding");
238 } else {
239 fwd_reg = obj_reg;
240 }
241
242 // ------------ obj and fwd are safe at this point --------------
243 // We allow for marked or old here for two reasons:
244 // 1. If this is a young collect, old objects wouldn't be marked. We've
245 // recently change the verifier traversal to only follow young objects
246 // during a young collect so this _shouldn't_ be necessary.
247 // 2. At present, we do not clear dead objects from the remembered set.
248 // Everything in the remembered set is old (ipso facto), so allowing for
249 // 'marked_or_old' covers the case of stale objects in rset.
250 // TODO: Just use 'is_marked' here.
251 switch (_options._verify_marked) {
252 case ShenandoahVerifier::_verify_marked_disable:
253 // skip
254 break;
255 case ShenandoahVerifier::_verify_marked_incomplete:
256 check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked_or_old(obj),
257 "Must be marked in incomplete bitmap");
258 break;
259 case ShenandoahVerifier::_verify_marked_complete:
260 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
261 "Must be marked in complete bitmap");
262 break;
263 case ShenandoahVerifier::_verify_marked_complete_except_references:
264 case ShenandoahVerifier::_verify_marked_complete_satb_empty:
265 check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked_or_old(obj),
266 "Must be marked in complete bitmap, except j.l.r.Reference referents");
267 break;
268 default:
269 assert(false, "Unhandled mark verification");
270 }
271
272 switch (_options._verify_forwarded) {
273 case ShenandoahVerifier::_verify_forwarded_disable:
274 // skip
275 break;
276 case ShenandoahVerifier::_verify_forwarded_none: {
277 check(ShenandoahAsserts::_safe_all, obj, (obj == fwd),
278 "Should not be forwarded");
279 break;
280 }
281 case ShenandoahVerifier::_verify_forwarded_allow: {
282 if (obj != fwd) {
283 check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,
284 "Forwardee should be in another region");
285 }
286 break;
287 }
288 default:
289 assert(false, "Unhandled forwarding verification");
290 }
291
292 switch (_options._verify_cset) {
293 case ShenandoahVerifier::_verify_cset_disable:
294 // skip
295 break;
296 case ShenandoahVerifier::_verify_cset_none:
297 check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),
298 "Should not have references to collection set");
299 break;
300 case ShenandoahVerifier::_verify_cset_forwarded:
301 if (_heap->in_collection_set(obj)) {
302 check(ShenandoahAsserts::_safe_all, obj, (obj != fwd),
303 "Object in collection set, should have forwardee");
304 }
305 break;
306 default:
307 assert(false, "Unhandled cset verification");
308 }
309
310 }
311
312 public:
313 /**
314 * Verify object with known interior reference.
315 * @param p interior reference where the object is referenced from; can be off-heap
316 * @param obj verified object
317 */
318 template <class T>
319 void verify_oop_at(T* p, oop obj) {
320 _interior_loc = p;
321 verify_oop(obj);
322 _interior_loc = nullptr;
323 }
324
325 /**
326 * Verify object without known interior reference.
327 * Useful when picking up the object at known offset in heap,
328 * but without knowing what objects reference it.
329 * @param obj verified object
330 */
331 void verify_oop_standalone(oop obj) {
332 _interior_loc = nullptr;
333 verify_oop(obj);
334 _interior_loc = nullptr;
335 }
336
337 /**
338 * Verify oop fields from this object.
339 * @param obj host object for verified fields
340 */
341 void verify_oops_from(oop obj) {
342 _loc = obj;
343 obj->oop_iterate(this);
344 _loc = nullptr;
345 }
346
347 void do_oop(oop* p) override { do_oop_work(p); }
348 void do_oop(narrowOop* p) override { do_oop_work(p); }
349 };
350
351 // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
352 // a subset (e.g. the young generation or old generation) of the total heap.
353 class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
354 private:
355 size_t _used, _committed, _garbage, _regions, _humongous_waste, _trashed_regions;
356 public:
357 ShenandoahCalculateRegionStatsClosure() :
358 _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0), _trashed_regions(0) {};
359
360 void heap_region_do(ShenandoahHeapRegion* r) override {
361 _used += r->used();
362 _garbage += r->garbage();
363 _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
364 if (r->is_humongous()) {
365 _humongous_waste += r->free();
366 }
367 if (r->is_trash()) {
368 _trashed_regions++;
369 }
370 _regions++;
371 log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
372 r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
373 }
374
375 size_t used() const { return _used; }
376 size_t committed() const { return _committed; }
377 size_t garbage() const { return _garbage; }
378 size_t regions() const { return _regions; }
379 size_t waste() const { return _humongous_waste; }
380
381 // span is the total memory affiliated with these stats (some of which is in use and other is available)
382 size_t span() const { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
383 size_t non_trashed_span() const { return (_regions - _trashed_regions) * ShenandoahHeapRegion::region_size_bytes(); }
384 };
385
386 class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
387 public:
388 ShenandoahCalculateRegionStatsClosure old;
389 ShenandoahCalculateRegionStatsClosure young;
390 ShenandoahCalculateRegionStatsClosure global;
391
392 void heap_region_do(ShenandoahHeapRegion* r) override {
393 switch (r->affiliation()) {
394 case FREE:
395 return;
396 case YOUNG_GENERATION:
397 young.heap_region_do(r);
398 global.heap_region_do(r);
399 break;
400 case OLD_GENERATION:
401 old.heap_region_do(r);
402 global.heap_region_do(r);
403 break;
404 default:
405 ShouldNotReachHere();
406 }
407 }
408
409 static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
410 log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
411 generation->name(),
412 byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
413 byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
414 }
415
416 static void validate_usage(const bool adjust_for_padding,
417 const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
418 ShenandoahHeap* heap = ShenandoahHeap::heap();
419 size_t generation_used = generation->used();
420 size_t generation_used_regions = generation->used_regions();
421 if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
422 size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
423 generation_used += pad;
424 }
425
426 guarantee(stats.used() == generation_used,
427 "%s: generation (%s) used size must be consistent: generation-used: " PROPERFMT ", regions-used: " PROPERFMT,
428 label, generation->name(), PROPERFMTARGS(generation_used), PROPERFMTARGS(stats.used()));
429
430 guarantee(stats.regions() == generation_used_regions,
431 "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
432 label, generation->name(), generation->used_regions(), stats.regions());
433
434 size_t generation_capacity = generation->max_capacity();
435 guarantee(stats.non_trashed_span() <= generation_capacity,
436 "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") * region size (" PROPERFMT
437 ") must not exceed current capacity (" PROPERFMT ")",
438 label, generation->name(), stats.regions(), PROPERFMTARGS(ShenandoahHeapRegion::region_size_bytes()),
439 PROPERFMTARGS(generation_capacity));
440
441 size_t humongous_waste = generation->get_humongous_waste();
442 guarantee(stats.waste() == humongous_waste,
443 "%s: generation (%s) humongous waste must be consistent: generation: " PROPERFMT ", regions: " PROPERFMT,
444 label, generation->name(), PROPERFMTARGS(humongous_waste), PROPERFMTARGS(stats.waste()));
445 }
446 };
447
448 class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
449 private:
450 ShenandoahHeap* _heap;
451 const char* _phase;
452 ShenandoahVerifier::VerifyRegions _regions;
453 public:
454 ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :
455 _heap(ShenandoahHeap::heap()),
456 _phase(phase),
457 _regions(regions) {};
458
459 void print_failure(ShenandoahHeapRegion* r, const char* label) {
460 ResourceMark rm;
461
462 ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);
463
464 stringStream ss;
465 r->print_on(&ss);
466 msg.append("%s", ss.as_string());
467
468 report_vm_error(__FILE__, __LINE__, msg.buffer());
469 }
470
471 void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {
472 if (!test) {
473 print_failure(r, msg);
474 }
475 }
476
477 void heap_region_do(ShenandoahHeapRegion* r) override {
478 switch (_regions) {
479 case ShenandoahVerifier::_verify_regions_disable:
480 break;
481 case ShenandoahVerifier::_verify_regions_notrash:
482 verify(r, !r->is_trash(),
483 "Should not have trash regions");
484 break;
485 case ShenandoahVerifier::_verify_regions_nocset:
486 verify(r, !r->is_cset(),
487 "Should not have cset regions");
488 break;
489 case ShenandoahVerifier::_verify_regions_notrash_nocset:
490 verify(r, !r->is_trash(),
491 "Should not have trash regions");
492 verify(r, !r->is_cset(),
493 "Should not have cset regions");
494 break;
495 default:
496 ShouldNotReachHere();
497 }
498
499 verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),
500 "Capacity should match region size");
501
502 verify(r, r->bottom() <= r->top(),
503 "Region top should not be less than bottom");
504
505 verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),
506 "Region TAMS should not be less than bottom");
507
508 verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),
509 "Complete TAMS should not be larger than top");
510
511 verify(r, r->get_live_data_bytes() <= r->capacity(),
512 "Live data cannot be larger than capacity");
513
514 verify(r, r->garbage() <= r->capacity(),
515 "Garbage cannot be larger than capacity");
516
517 verify(r, r->used() <= r->capacity(),
518 "Used cannot be larger than capacity");
519
520 verify(r, r->get_shared_allocs() <= r->capacity(),
521 "Shared alloc count should not be larger than capacity");
522
523 verify(r, r->get_tlab_allocs() <= r->capacity(),
524 "TLAB alloc count should not be larger than capacity");
525
526 verify(r, r->get_gclab_allocs() <= r->capacity(),
527 "GCLAB alloc count should not be larger than capacity");
528
529 verify(r, r->get_plab_allocs() <= r->capacity(),
530 "PLAB alloc count should not be larger than capacity");
531
532 verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
533 "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
534
535 verify(r, !r->is_empty() || !r->has_live(),
536 "Empty regions should not have live data");
537
538 verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
539 "Transitional: region flags and collection set agree");
540 }
541 };
542
543 class ShenandoahVerifierReachableTask : public WorkerTask {
544 private:
545 const char* _label;
546 ShenandoahVerifier::VerifyOptions _options;
547 ShenandoahHeap* _heap;
548 ShenandoahLivenessData* _ld;
549 MarkBitMap* _bitmap;
550 volatile size_t _processed;
551
552 public:
553 ShenandoahVerifierReachableTask(MarkBitMap* bitmap,
554 ShenandoahLivenessData* ld,
555 const char* label,
556 ShenandoahVerifier::VerifyOptions options) :
557 WorkerTask("Shenandoah Verifier Reachable Objects"),
558 _label(label),
559 _options(options),
560 _heap(ShenandoahHeap::heap()),
561 _ld(ld),
562 _bitmap(bitmap),
563 _processed(0) {};
564
565 size_t processed() const {
566 return _processed;
567 }
568
569 void work(uint worker_id) override {
570 ResourceMark rm;
571 ShenandoahVerifierStack stack;
572
573 // On level 2, we need to only check the roots once.
574 // On level 3, we want to check the roots, and seed the local stack.
575 // It is a lesser evil to accept multiple root scans at level 3, because
576 // extended parallelism would buy us out.
577 if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))
578 || (ShenandoahVerifyLevel >= 3)) {
579 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
580 ShenandoahMessageBuffer("%s, Roots", _label),
581 _options);
582 if (_heap->unload_classes()) {
583 ShenandoahRootVerifier::strong_roots_do(&cl);
584 } else {
585 ShenandoahRootVerifier::roots_do(&cl);
586 }
587 }
588
589 size_t processed = 0;
590
591 if (ShenandoahVerifyLevel >= 3) {
592 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
593 ShenandoahMessageBuffer("%s, Reachable", _label),
594 _options);
595 while (!stack.is_empty()) {
596 processed++;
597 ShenandoahVerifierTask task = stack.pop();
598 cl.verify_oops_from(task.obj());
599 }
600 }
601
602 Atomic::add(&_processed, processed, memory_order_relaxed);
603 }
604 };
605
606 class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
607 public:
608 void do_thread(Thread* thread) override {
609 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
610 if (!queue.is_empty()) {
611 fatal("All SATB buffers should have been flushed during mark");
612 }
613 }
614 };
615
616 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
617 private:
618 const char* _label;
619 ShenandoahVerifier::VerifyOptions _options;
620 ShenandoahHeap *_heap;
621 MarkBitMap* _bitmap;
622 ShenandoahLivenessData* _ld;
623 volatile size_t _claimed;
624 volatile size_t _processed;
625 ShenandoahGeneration* _generation;
626
627 public:
628 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
629 ShenandoahLivenessData* ld,
630 const char* label,
631 ShenandoahVerifier::VerifyOptions options) :
632 WorkerTask("Shenandoah Verifier Marked Objects"),
633 _label(label),
634 _options(options),
635 _heap(ShenandoahHeap::heap()),
636 _bitmap(bitmap),
637 _ld(ld),
638 _claimed(0),
639 _processed(0),
640 _generation(nullptr) {
641 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
642 Threads::change_thread_claim_token();
643 }
644
645 if (_heap->mode()->is_generational()) {
646 _generation = _heap->gc_generation();
647 assert(_generation != nullptr, "Expected active generation in this mode.");
648 shenandoah_assert_generations_reconciled();
649 }
650 };
651
652 size_t processed() {
653 return Atomic::load(&_processed);
654 }
655
656 void work(uint worker_id) override {
657 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
658 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
659 Threads::possibly_parallel_threads_do(true, &verify_satb);
660 }
661
662 ShenandoahVerifierStack stack;
663 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
664 ShenandoahMessageBuffer("%s, Marked", _label),
665 _options);
666
667 while (true) {
668 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
669 if (v < _heap->num_regions()) {
670 ShenandoahHeapRegion* r = _heap->get_region(v);
671 if (!in_generation(r)) {
672 continue;
673 }
674
675 if (!r->is_humongous() && !r->is_trash()) {
676 work_regular(r, stack, cl);
677 } else if (r->is_humongous_start()) {
678 work_humongous(r, stack, cl);
679 }
680 } else {
681 break;
682 }
683 }
684 }
685
686 bool in_generation(ShenandoahHeapRegion* r) {
687 return _generation == nullptr || _generation->contains(r);
688 }
689
690 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
691 size_t processed = 0;
692 HeapWord* obj = r->bottom();
693 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
694 verify_and_follow(obj, stack, cl, &processed);
695 }
696 Atomic::add(&_processed, processed, memory_order_relaxed);
697 }
698
699 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
700 size_t processed = 0;
701 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
702 HeapWord* tams = ctx->top_at_mark_start(r);
703
704 // Bitmaps, before TAMS
705 if (tams > r->bottom()) {
706 HeapWord* start = r->bottom();
707 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
708
709 while (addr < tams) {
710 verify_and_follow(addr, stack, cl, &processed);
711 addr += 1;
712 if (addr < tams) {
713 addr = ctx->get_next_marked_addr(addr, tams);
714 }
715 }
716 }
717
718 // Size-based, after TAMS
719 {
720 HeapWord* limit = r->top();
721 HeapWord* addr = tams;
722
723 while (addr < limit) {
724 verify_and_follow(addr, stack, cl, &processed);
725 addr += cast_to_oop(addr)->size();
726 }
727 }
728
729 Atomic::add(&_processed, processed, memory_order_relaxed);
730 }
731
732 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
733 if (!_bitmap->par_mark(addr)) return;
734
735 // Verify the object itself:
736 oop obj = cast_to_oop(addr);
737 cl.verify_oop_standalone(obj);
738
739 // Verify everything reachable from that object too, hopefully realizing
740 // everything was already marked, and never touching further:
741 if (!is_instance_ref_klass(obj->klass())) {
742 cl.verify_oops_from(obj);
743 (*processed)++;
744 }
745 while (!stack.is_empty()) {
746 ShenandoahVerifierTask task = stack.pop();
747 cl.verify_oops_from(task.obj());
748 (*processed)++;
749 }
750 }
751 };
752
753 class VerifyThreadGCState : public ThreadClosure {
754 private:
755 const char* const _label;
756 char const _expected;
757
758 public:
759 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
760 void do_thread(Thread* t) override {
761 char actual = ShenandoahThreadLocalData::gc_state(t);
762 if (!verify_gc_state(actual, _expected)) {
763 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
764 }
765 }
766
767 static bool verify_gc_state(char actual, char expected) {
768 // Old generation marking is allowed in all states.
769 if (ShenandoahHeap::heap()->mode()->is_generational()) {
770 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
771 } else {
772 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
773 return (actual == expected);
774 }
775 }
776 };
777
778 void ShenandoahVerifier::verify_at_safepoint(const char* label,
779 VerifyRememberedSet remembered,
780 VerifyForwarded forwarded, VerifyMarked marked,
781 VerifyCollectionSet cset,
782 VerifyLiveness liveness, VerifyRegions regions,
783 VerifySize sizeness,
784 VerifyGCState gcstate) {
785 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
786 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
787
788 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
789
790 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
791 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
792
793 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
794
795 // GC state checks
796 {
797 char expected = -1;
798 bool enabled;
799 switch (gcstate) {
800 case _verify_gcstate_disable:
801 enabled = false;
802 break;
803 case _verify_gcstate_forwarded:
804 enabled = true;
805 expected = ShenandoahHeap::HAS_FORWARDED;
806 break;
807 case _verify_gcstate_evacuation:
808 enabled = true;
809 expected = ShenandoahHeap::EVACUATION;
810 if (!_heap->is_stw_gc_in_progress()) {
811 // Only concurrent GC sets this.
812 expected |= ShenandoahHeap::WEAK_ROOTS;
813 }
814 break;
815 case _verify_gcstate_updating:
816 enabled = true;
817 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
818 break;
819 case _verify_gcstate_stable:
820 enabled = true;
821 expected = ShenandoahHeap::STABLE;
822 break;
823 case _verify_gcstate_stable_weakroots:
824 enabled = true;
825 expected = ShenandoahHeap::STABLE;
826 if (!_heap->is_stw_gc_in_progress()) {
827 // Only concurrent GC sets this.
828 expected |= ShenandoahHeap::WEAK_ROOTS;
829 }
830 break;
831 default:
832 enabled = false;
833 assert(false, "Unhandled gc-state verification");
834 }
835
836 if (enabled) {
837 char actual = _heap->gc_state();
838
839 bool is_marking = (actual & ShenandoahHeap::MARKING);
840 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
841 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
842
843 // Old generation marking is allowed in all states.
844 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
845 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
846 }
847
848 VerifyThreadGCState vtgcs(label, expected);
849 Threads::java_threads_do(&vtgcs);
850 }
851 }
852
853 // Deactivate barriers temporarily: Verifier wants plain heap accesses
854 ShenandoahGCStateResetter resetter;
855
856 // Heap size checks
857 {
858 ShenandoahHeapLocker lock(_heap->lock());
859
860 ShenandoahCalculateRegionStatsClosure cl;
861 _heap->heap_region_iterate(&cl);
862 size_t heap_used;
863 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
864 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
865 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
866 } else if (sizeness != _verify_size_disable) {
867 heap_used = _heap->used();
868 }
869 if (sizeness != _verify_size_disable) {
870 guarantee(cl.used() == heap_used,
871 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
872 label,
873 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
874 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
875 }
876 size_t heap_committed = _heap->committed();
877 guarantee(cl.committed() == heap_committed,
878 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
879 label,
880 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
881 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
882 }
883
884 log_debug(gc)("Safepoint verification finished heap usage verification");
885
886 ShenandoahGeneration* generation;
887 if (_heap->mode()->is_generational()) {
888 generation = _heap->gc_generation();
889 guarantee(generation != nullptr, "Need to know which generation to verify.");
890 shenandoah_assert_generations_reconciled();
891 } else {
892 generation = nullptr;
893 }
894
895 if (generation != nullptr) {
896 ShenandoahHeapLocker lock(_heap->lock());
897
898 switch (remembered) {
899 case _verify_remembered_disable:
900 break;
901 case _verify_remembered_before_marking:
902 log_debug(gc)("Safepoint verification of remembered set at mark");
903 verify_rem_set_before_mark();
904 break;
905 case _verify_remembered_before_updating_references:
906 log_debug(gc)("Safepoint verification of remembered set at update ref");
907 verify_rem_set_before_update_ref();
908 break;
909 case _verify_remembered_after_full_gc:
910 log_debug(gc)("Safepoint verification of remembered set after full gc");
911 verify_rem_set_after_full_gc();
912 break;
913 default:
914 fatal("Unhandled remembered set verification mode");
915 }
916
917 ShenandoahGenerationStatsClosure cl;
918 _heap->heap_region_iterate(&cl);
919
920 if (LogTarget(Debug, gc)::is_enabled()) {
921 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
922 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
923 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
924 }
925 if (sizeness == _verify_size_adjusted_for_padding) {
926 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
927 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
928 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
929 } else if (sizeness == _verify_size_exact) {
930 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
931 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
932 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
933 }
934 // else: sizeness must equal _verify_size_disable
935 }
936
937 log_debug(gc)("Safepoint verification finished remembered set verification");
938
939 // Internal heap region checks
940 if (ShenandoahVerifyLevel >= 1) {
941 ShenandoahVerifyHeapRegionClosure cl(label, regions);
942 if (generation != nullptr) {
943 generation->heap_region_iterate(&cl);
944 } else {
945 _heap->heap_region_iterate(&cl);
946 }
947 }
948
949 log_debug(gc)("Safepoint verification finished heap region closure verification");
950
951 OrderAccess::fence();
952
953 if (UseTLAB) {
954 _heap->labs_make_parsable();
955 }
956
957 // Allocate temporary bitmap for storing marking wavefront:
958 _verification_bit_map->clear();
959
960 // Allocate temporary array for storing liveness data
961 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
962 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
963
964 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
965
966 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
967 // This verifies what application can see, since it only cares about reachable objects.
968 size_t count_reachable = 0;
969 if (ShenandoahVerifyLevel >= 2) {
970 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
971 _heap->workers()->run_task(&task);
972 count_reachable = task.processed();
973 }
974
975 log_debug(gc)("Safepoint verification finished getting initial reachable set");
976
977 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
978 // not the application, can see during the region scans. There is no reason to process the objects
979 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
980 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
981 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
982 // version
983
984 size_t count_marked = 0;
985 if (ShenandoahVerifyLevel >= 4 &&
986 (marked == _verify_marked_complete ||
987 marked == _verify_marked_complete_except_references ||
988 marked == _verify_marked_complete_satb_empty)) {
989 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
990 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
991 _heap->workers()->run_task(&task);
992 count_marked = task.processed();
993 } else {
994 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
995 }
996
997 log_debug(gc)("Safepoint verification finished walking marked objects");
998
999 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
1000 // marked objects.
1001
1002 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
1003 for (size_t i = 0; i < _heap->num_regions(); i++) {
1004 ShenandoahHeapRegion* r = _heap->get_region(i);
1005 if (generation != nullptr && !generation->contains(r)) {
1006 continue;
1007 }
1008
1009 juint verf_live = 0;
1010 if (r->is_humongous()) {
1011 // For humongous objects, test if start region is marked live, and if so,
1012 // all humongous regions in that chain have live data equal to their "used".
1013 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1014 if (start_live > 0) {
1015 verf_live = (juint)(r->used() / HeapWordSize);
1016 }
1017 } else {
1018 verf_live = Atomic::load(&ld[r->index()]);
1019 }
1020
1021 size_t reg_live = r->get_live_data_words();
1022 if (reg_live != verf_live) {
1023 stringStream ss;
1024 r->print_on(&ss);
1025 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
1026 label, reg_live, verf_live, ss.freeze());
1027 }
1028 }
1029 }
1030
1031 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1032
1033
1034 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
1035 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1036
1037 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1038 }
1039
1040 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1041 verify_at_safepoint(
1042 "Generic Verification",
1043 _verify_remembered_disable, // do not verify remembered set
1044 _verify_forwarded_allow, // conservatively allow forwarded
1045 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1046 _verify_cset_disable, // cset may be inconsistent
1047 _verify_liveness_disable, // no reliable liveness data
1048 _verify_regions_disable, // no reliable region data
1049 _verify_size_exact, // expect generation and heap sizes to match exactly
1050 _verify_gcstate_disable // no data about gcstate
1051 );
1052 }
1053
1054 void ShenandoahVerifier::verify_before_concmark() {
1055 verify_at_safepoint(
1056 "Before Mark",
1057 _verify_remembered_before_marking,
1058 // verify read-only remembered set from bottom() to top()
1059 _verify_forwarded_none, // UR should have fixed up
1060 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1061 _verify_cset_none, // UR should have fixed this
1062 _verify_liveness_disable, // no reliable liveness data
1063 _verify_regions_notrash, // no trash regions
1064 _verify_size_exact, // expect generation and heap sizes to match exactly
1065 _verify_gcstate_stable // there are no forwarded objects
1066 );
1067 }
1068
1069 void ShenandoahVerifier::verify_after_concmark() {
1070 verify_at_safepoint(
1071 "After Mark",
1072 _verify_remembered_disable, // do not verify remembered set
1073 _verify_forwarded_none, // no forwarded references
1074 _verify_marked_complete_satb_empty,
1075 // bitmaps as precise as we can get, except dangling j.l.r.Refs
1076 _verify_cset_none, // no references to cset anymore
1077 _verify_liveness_complete, // liveness data must be complete here
1078 _verify_regions_disable, // trash regions not yet recycled
1079 _verify_size_exact, // expect generation and heap sizes to match exactly
1080 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1081 );
1082 }
1083
1084 void ShenandoahVerifier::verify_before_evacuation() {
1085 verify_at_safepoint(
1086 "Before Evacuation",
1087 _verify_remembered_disable, // do not verify remembered set
1088 _verify_forwarded_none, // no forwarded references
1089 _verify_marked_complete_except_references, // walk over marked objects too
1090 _verify_cset_disable, // non-forwarded references to cset expected
1091 _verify_liveness_complete, // liveness data must be complete here
1092 _verify_regions_disable, // trash regions not yet recycled
1093 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1094 // for promote in place padding
1095 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1096 );
1097 }
1098
1099 void ShenandoahVerifier::verify_during_evacuation() {
1100 verify_at_safepoint(
1101 "During Evacuation",
1102 _verify_remembered_disable, // do not verify remembered set
1103 _verify_forwarded_allow, // some forwarded references are allowed
1104 _verify_marked_disable, // walk only roots
1105 _verify_cset_disable, // some cset references are not forwarded yet
1106 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1107 _verify_regions_disable, // trash regions not yet recycled
1108 _verify_size_disable, // we don't know how much of promote-in-place work has been completed
1109 _verify_gcstate_evacuation // evacuation is in progress
1110 );
1111 }
1112
1113 void ShenandoahVerifier::verify_after_evacuation() {
1114 verify_at_safepoint(
1115 "After Evacuation",
1116 _verify_remembered_disable, // do not verify remembered set
1117 _verify_forwarded_allow, // objects are still forwarded
1118 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1119 _verify_cset_forwarded, // all cset refs are fully forwarded
1120 _verify_liveness_disable, // no reliable liveness data anymore
1121 _verify_regions_notrash, // trash regions have been recycled already
1122 _verify_size_exact, // expect generation and heap sizes to match exactly
1123 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1124 );
1125 }
1126
1127 void ShenandoahVerifier::verify_before_updaterefs() {
1128 verify_at_safepoint(
1129 "Before Updating References",
1130 _verify_remembered_before_updating_references, // verify read-write remembered set
1131 _verify_forwarded_allow, // forwarded references allowed
1132 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1133 _verify_cset_forwarded, // all cset refs are fully forwarded
1134 _verify_liveness_disable, // no reliable liveness data anymore
1135 _verify_regions_notrash, // trash regions have been recycled already
1136 _verify_size_exact, // expect generation and heap sizes to match exactly
1137 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1138 );
1139 }
1140
1141 // We have not yet cleanup (reclaimed) the collection set
1142 void ShenandoahVerifier::verify_after_updaterefs() {
1143 verify_at_safepoint(
1144 "After Updating References",
1145 _verify_remembered_disable, // do not verify remembered set
1146 _verify_forwarded_none, // no forwarded references
1147 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1148 _verify_cset_none, // no cset references, all updated
1149 _verify_liveness_disable, // no reliable liveness data anymore
1150 _verify_regions_nocset, // no cset regions, trash regions have appeared
1151 _verify_size_exact, // expect generation and heap sizes to match exactly
1152 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1153 );
1154 }
1155
1156 void ShenandoahVerifier::verify_after_degenerated() {
1157 verify_at_safepoint(
1158 "After Degenerated GC",
1159 _verify_remembered_disable, // do not verify remembered set
1160 _verify_forwarded_none, // all objects are non-forwarded
1161 _verify_marked_complete, // all objects are marked in complete bitmap
1162 _verify_cset_none, // no cset references
1163 _verify_liveness_disable, // no reliable liveness data anymore
1164 _verify_regions_notrash_nocset, // no trash, no cset
1165 _verify_size_exact, // expect generation and heap sizes to match exactly
1166 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1167 );
1168 }
1169
1170 void ShenandoahVerifier::verify_before_fullgc() {
1171 verify_at_safepoint(
1172 "Before Full GC",
1173 _verify_remembered_disable, // do not verify remembered set
1174 _verify_forwarded_allow, // can have forwarded objects
1175 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1176 _verify_cset_disable, // cset might be foobared
1177 _verify_liveness_disable, // no reliable liveness data anymore
1178 _verify_regions_disable, // no reliable region data here
1179 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1180 _verify_gcstate_disable // no reliable gcstate data
1181 );
1182 }
1183
1184 void ShenandoahVerifier::verify_after_fullgc() {
1185 verify_at_safepoint(
1186 "After Full GC",
1187 _verify_remembered_after_full_gc, // verify read-write remembered set
1188 _verify_forwarded_none, // all objects are non-forwarded
1189 _verify_marked_complete, // all objects are marked in complete bitmap
1190 _verify_cset_none, // no cset references
1191 _verify_liveness_disable, // no reliable liveness data anymore
1192 _verify_regions_notrash_nocset, // no trash, no cset
1193 _verify_size_exact, // expect generation and heap sizes to match exactly
1194 _verify_gcstate_stable // full gc cleaned up everything
1195 );
1196 }
1197
1198 // TODO: Why this closure does not visit metadata?
1199 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1200 private:
1201 template <class T>
1202 void do_oop_work(T* p) {
1203 T o = RawAccess<>::oop_load(p);
1204 if (!CompressedOops::is_null(o)) {
1205 oop obj = CompressedOops::decode_not_null(o);
1206 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1207 if (obj != fwd) {
1208 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1209 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1210 }
1211 }
1212 }
1213
1214 public:
1215 void do_oop(narrowOop* p) { do_oop_work(p); }
1216 void do_oop(oop* p) { do_oop_work(p); }
1217 };
1218
1219 // TODO: Why this closure does not visit metadata?
1220 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1221 private:
1222 template <class T>
1223 void do_oop_work(T* p) {
1224 T o = RawAccess<>::oop_load(p);
1225 if (!CompressedOops::is_null(o)) {
1226 oop obj = CompressedOops::decode_not_null(o);
1227 ShenandoahHeap* heap = ShenandoahHeap::heap();
1228
1229 if (!heap->marking_context()->is_marked_or_old(obj)) {
1230 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1231 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1232 }
1233
1234 if (heap->in_collection_set(obj)) {
1235 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1236 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1237 }
1238
1239 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1240 if (obj != fwd) {
1241 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1242 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1243 }
1244 }
1245 }
1246
1247 public:
1248 void do_oop(narrowOop* p) override { do_oop_work(p); }
1249 void do_oop(oop* p) override { do_oop_work(p); }
1250 };
1251
1252 void ShenandoahVerifier::verify_roots_in_to_space() {
1253 ShenandoahVerifyInToSpaceClosure cl;
1254 ShenandoahRootVerifier::roots_do(&cl);
1255 }
1256
1257 void ShenandoahVerifier::verify_roots_no_forwarded() {
1258 ShenandoahVerifyNoForwared cl;
1259 ShenandoahRootVerifier::roots_do(&cl);
1260 }
1261
1262 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1263 protected:
1264 bool const _init_mark;
1265 ShenandoahGenerationalHeap* const _heap;
1266 RememberedScanner* const _scanner;
1267
1268 public:
1269 // Argument distinguishes between initial mark or start of update refs verification.
1270 explicit ShenandoahVerifyRemSetClosure(bool init_mark) :
1271 _init_mark(init_mark),
1272 _heap(ShenandoahGenerationalHeap::heap()),
1273 _scanner(_heap->old_generation()->card_scan()) {}
1274
1275 template<class T>
1276 inline void work(T* p) {
1277 T o = RawAccess<>::oop_load(p);
1278 if (!CompressedOops::is_null(o)) {
1279 oop obj = CompressedOops::decode_not_null(o);
1280 if (_heap->is_in_young(obj)) {
1281 size_t card_index = _scanner->card_index_for_addr((HeapWord*) p);
1282 if (_init_mark && !_scanner->is_card_dirty(card_index)) {
1283 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1284 "Verify init-mark remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1285 } else if (!_init_mark && !_scanner->is_write_card_dirty(card_index)) {
1286 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1287 "Verify init-update-refs remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1288 }
1289 }
1290 }
1291 }
1292
1293 void do_oop(narrowOop* p) override { work(p); }
1294 void do_oop(oop* p) override { work(p); }
1295 };
1296
1297 void ShenandoahVerifier::help_verify_region_rem_set(ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx, HeapWord* from,
1298 HeapWord* top, HeapWord* registration_watermark, const char* message) {
1299 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1300 ShenandoahVerifyRemSetClosure check_interesting_pointers(false);
1301
1302 HeapWord* obj_addr = from;
1303 if (r->is_humongous_start()) {
1304 oop obj = cast_to_oop(obj_addr);
1305 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1306 size_t card_index = scanner->card_index_for_addr(obj_addr);
1307 // For humongous objects, the typical object is an array, so the following checks may be overkill
1308 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1309 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1310 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1311 obj->oop_iterate(&check_interesting_pointers);
1312 }
1313 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1314 }
1315 // else, this humongous object is not live so no need to verify its internal pointers
1316
1317 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1318 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1319 "object not properly registered", __FILE__, __LINE__);
1320 }
1321 } else if (!r->is_humongous()) {
1322 while (obj_addr < top) {
1323 oop obj = cast_to_oop(obj_addr);
1324 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1325 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1326 size_t card_index = scanner->card_index_for_addr(obj_addr);
1327 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1328 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1329 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1330 obj->oop_iterate(&check_interesting_pointers);
1331 }
1332 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1333
1334 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1335 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1336 "object not properly registered", __FILE__, __LINE__);
1337 }
1338 obj_addr += obj->size();
1339 } else {
1340 // This object is not live so we don't verify dirty cards contained therein
1341 HeapWord* tams = ctx->top_at_mark_start(r);
1342 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1343 }
1344 }
1345 }
1346 }
1347
1348 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1349 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1350 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1351 // restore them until the start of evacuation.
1352 void ShenandoahVerifier::verify_rem_set_before_mark() {
1353 shenandoah_assert_safepoint();
1354 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1355
1356 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1357 ShenandoahVerifyRemSetClosure check_interesting_pointers(true);
1358 ShenandoahMarkingContext* ctx;
1359
1360 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1361 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1362
1363 shenandoah_assert_generations_reconciled();
1364 if (old_generation->is_mark_complete() || _heap->gc_generation()->is_global()) {
1365 ctx = _heap->complete_marking_context();
1366 } else {
1367 ctx = nullptr;
1368 }
1369
1370 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1371 ShenandoahHeapRegion* r = _heap->get_region(i);
1372 HeapWord* tams = (ctx != nullptr) ? ctx->top_at_mark_start(r) : nullptr;
1373
1374 // TODO: Is this replaceable with call to help_verify_region_rem_set?
1375
1376 if (r->is_old() && r->is_active()) {
1377 HeapWord* obj_addr = r->bottom();
1378 if (r->is_humongous_start()) {
1379 oop obj = cast_to_oop(obj_addr);
1380 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1381 // For humongous objects, the typical object is an array, so the following checks may be overkill
1382 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1383 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1384 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1385 obj->oop_iterate(&check_interesting_pointers);
1386 }
1387 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1388 }
1389 // else, this humongous object is not marked so no need to verify its internal pointers
1390 if (!scanner->verify_registration(obj_addr, ctx)) {
1391 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1392 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1393 }
1394 } else if (!r->is_humongous()) {
1395 HeapWord* top = r->top();
1396 while (obj_addr < top) {
1397 oop obj = cast_to_oop(obj_addr);
1398 // ctx->is_marked() returns true if mark bit set (TAMS not relevant during init mark)
1399 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1400 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1401 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1402 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1403 obj->oop_iterate(&check_interesting_pointers);
1404 }
1405 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1406 if (!scanner->verify_registration(obj_addr, ctx)) {
1407 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1408 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1409 }
1410 obj_addr += obj->size();
1411 } else {
1412 // This object is not live so we don't verify dirty cards contained therein
1413 assert(tams != nullptr, "If object is not live, ctx and tams should be non-null");
1414 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1415 }
1416 }
1417 } // else, we ignore humongous continuation region
1418 } // else, this is not an OLD region so we ignore it
1419 } // all regions have been processed
1420 }
1421
1422 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1423 shenandoah_assert_safepoint();
1424 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1425
1426 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1427 ShenandoahHeapRegion* r = _heap->get_region(i);
1428 if (r->is_old() && !r->is_cset()) {
1429 help_verify_region_rem_set(r, nullptr, r->bottom(), r->top(), r->top(), "Remembered set violation at end of Full GC");
1430 }
1431 }
1432 }
1433
1434 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1435 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1436 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1437 // all PLABS are retired immediately before the start of update refs.
1438 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1439 shenandoah_assert_safepoint();
1440 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1441
1442 ShenandoahMarkingContext* ctx;
1443
1444 shenandoah_assert_generations_reconciled();
1445 if (_heap->old_generation()->is_mark_complete() || _heap->gc_generation()->is_global()) {
1446 ctx = _heap->complete_marking_context();
1447 } else {
1448 ctx = nullptr;
1449 }
1450
1451 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1452 ShenandoahHeapRegion* r = _heap->get_region(i);
1453 if (r->is_old() && !r->is_cset()) {
1454 help_verify_region_rem_set(r, ctx, r->bottom(), r->top(), r->get_update_watermark(),
1455 "Remembered set violation at init-update-references");
1456 }
1457 }
1458 }
1459
1460 void ShenandoahVerifier::verify_before_rebuilding_free_set() {
1461 ShenandoahGenerationStatsClosure cl;
1462 _heap->heap_region_iterate(&cl);
1463
1464 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
1465 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
1466 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
1467 }