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 (!is_empty(queue)) {
611 fatal("All SATB buffers should have been flushed during mark");
612 }
613 }
614 private:
615 bool is_empty(SATBMarkQueue& queue) {
616 return queue.buffer() == nullptr || queue.index() == queue.capacity();
617 }
618 };
619
620 class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
621 private:
622 const char* _label;
623 ShenandoahVerifier::VerifyOptions _options;
624 ShenandoahHeap *_heap;
625 MarkBitMap* _bitmap;
626 ShenandoahLivenessData* _ld;
627 volatile size_t _claimed;
628 volatile size_t _processed;
629 ShenandoahGeneration* _generation;
630
631 public:
632 ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
633 ShenandoahLivenessData* ld,
634 const char* label,
635 ShenandoahVerifier::VerifyOptions options) :
636 WorkerTask("Shenandoah Verifier Marked Objects"),
637 _label(label),
638 _options(options),
639 _heap(ShenandoahHeap::heap()),
640 _bitmap(bitmap),
641 _ld(ld),
642 _claimed(0),
643 _processed(0),
644 _generation(nullptr) {
645 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
646 Threads::change_thread_claim_token();
647 }
648
649 if (_heap->mode()->is_generational()) {
650 _generation = _heap->gc_generation();
651 assert(_generation != nullptr, "Expected active generation in this mode.");
652 shenandoah_assert_generations_reconciled();
653 }
654 };
655
656 size_t processed() {
657 return Atomic::load(&_processed);
658 }
659
660 void work(uint worker_id) override {
661 if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
662 ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
663 Threads::possibly_parallel_threads_do(true, &verify_satb);
664 }
665
666 ShenandoahVerifierStack stack;
667 ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
668 ShenandoahMessageBuffer("%s, Marked", _label),
669 _options);
670
671 while (true) {
672 size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
673 if (v < _heap->num_regions()) {
674 ShenandoahHeapRegion* r = _heap->get_region(v);
675 if (!in_generation(r)) {
676 continue;
677 }
678
679 if (!r->is_humongous() && !r->is_trash()) {
680 work_regular(r, stack, cl);
681 } else if (r->is_humongous_start()) {
682 work_humongous(r, stack, cl);
683 }
684 } else {
685 break;
686 }
687 }
688 }
689
690 bool in_generation(ShenandoahHeapRegion* r) {
691 return _generation == nullptr || _generation->contains(r);
692 }
693
694 virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
695 size_t processed = 0;
696 HeapWord* obj = r->bottom();
697 if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
698 verify_and_follow(obj, stack, cl, &processed);
699 }
700 Atomic::add(&_processed, processed, memory_order_relaxed);
701 }
702
703 virtual void work_regular(ShenandoahHeapRegion *r, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl) {
704 size_t processed = 0;
705 ShenandoahMarkingContext* ctx = _heap->complete_marking_context();
706 HeapWord* tams = ctx->top_at_mark_start(r);
707
708 // Bitmaps, before TAMS
709 if (tams > r->bottom()) {
710 HeapWord* start = r->bottom();
711 HeapWord* addr = ctx->get_next_marked_addr(start, tams);
712
713 while (addr < tams) {
714 verify_and_follow(addr, stack, cl, &processed);
715 addr += 1;
716 if (addr < tams) {
717 addr = ctx->get_next_marked_addr(addr, tams);
718 }
719 }
720 }
721
722 // Size-based, after TAMS
723 {
724 HeapWord* limit = r->top();
725 HeapWord* addr = tams;
726
727 while (addr < limit) {
728 verify_and_follow(addr, stack, cl, &processed);
729 addr += cast_to_oop(addr)->size();
730 }
731 }
732
733 Atomic::add(&_processed, processed, memory_order_relaxed);
734 }
735
736 void verify_and_follow(HeapWord *addr, ShenandoahVerifierStack &stack, ShenandoahVerifyOopClosure &cl, size_t *processed) {
737 if (!_bitmap->par_mark(addr)) return;
738
739 // Verify the object itself:
740 oop obj = cast_to_oop(addr);
741 cl.verify_oop_standalone(obj);
742
743 // Verify everything reachable from that object too, hopefully realizing
744 // everything was already marked, and never touching further:
745 if (!is_instance_ref_klass(obj->klass())) {
746 cl.verify_oops_from(obj);
747 (*processed)++;
748 }
749 while (!stack.is_empty()) {
750 ShenandoahVerifierTask task = stack.pop();
751 cl.verify_oops_from(task.obj());
752 (*processed)++;
753 }
754 }
755 };
756
757 class VerifyThreadGCState : public ThreadClosure {
758 private:
759 const char* const _label;
760 char const _expected;
761
762 public:
763 VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
764 void do_thread(Thread* t) override {
765 char actual = ShenandoahThreadLocalData::gc_state(t);
766 if (!verify_gc_state(actual, _expected)) {
767 fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
768 }
769 }
770
771 static bool verify_gc_state(char actual, char expected) {
772 // Old generation marking is allowed in all states.
773 if (ShenandoahHeap::heap()->mode()->is_generational()) {
774 return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
775 } else {
776 assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
777 return (actual == expected);
778 }
779 }
780 };
781
782 void ShenandoahVerifier::verify_at_safepoint(const char* label,
783 VerifyRememberedSet remembered,
784 VerifyForwarded forwarded, VerifyMarked marked,
785 VerifyCollectionSet cset,
786 VerifyLiveness liveness, VerifyRegions regions,
787 VerifySize sizeness,
788 VerifyGCState gcstate) {
789 guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
790 guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
791
792 ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
793
794 // Avoid side-effect of changing workers' active thread count, but bypass concurrent/parallel protocol check
795 ShenandoahPushWorkerScope verify_worker_scope(_heap->workers(), _heap->max_workers(), false /*bypass check*/);
796
797 log_info(gc,start)("Verify %s, Level " INTX_FORMAT, label, ShenandoahVerifyLevel);
798
799 // GC state checks
800 {
801 char expected = -1;
802 bool enabled;
803 switch (gcstate) {
804 case _verify_gcstate_disable:
805 enabled = false;
806 break;
807 case _verify_gcstate_forwarded:
808 enabled = true;
809 expected = ShenandoahHeap::HAS_FORWARDED;
810 break;
811 case _verify_gcstate_evacuation:
812 enabled = true;
813 expected = ShenandoahHeap::EVACUATION;
814 if (!_heap->is_stw_gc_in_progress()) {
815 // Only concurrent GC sets this.
816 expected |= ShenandoahHeap::WEAK_ROOTS;
817 }
818 break;
819 case _verify_gcstate_updating:
820 enabled = true;
821 expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::UPDATEREFS;
822 break;
823 case _verify_gcstate_stable:
824 enabled = true;
825 expected = ShenandoahHeap::STABLE;
826 break;
827 case _verify_gcstate_stable_weakroots:
828 enabled = true;
829 expected = ShenandoahHeap::STABLE;
830 if (!_heap->is_stw_gc_in_progress()) {
831 // Only concurrent GC sets this.
832 expected |= ShenandoahHeap::WEAK_ROOTS;
833 }
834 break;
835 default:
836 enabled = false;
837 assert(false, "Unhandled gc-state verification");
838 }
839
840 if (enabled) {
841 char actual = _heap->gc_state();
842
843 bool is_marking = (actual & ShenandoahHeap::MARKING);
844 bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
845 assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
846
847 // Old generation marking is allowed in all states.
848 if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
849 fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
850 }
851
852 VerifyThreadGCState vtgcs(label, expected);
853 Threads::java_threads_do(&vtgcs);
854 }
855 }
856
857 // Deactivate barriers temporarily: Verifier wants plain heap accesses
858 ShenandoahGCStateResetter resetter;
859
860 // Heap size checks
861 {
862 ShenandoahHeapLocker lock(_heap->lock());
863
864 ShenandoahCalculateRegionStatsClosure cl;
865 _heap->heap_region_iterate(&cl);
866 size_t heap_used;
867 if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
868 // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
869 heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
870 } else if (sizeness != _verify_size_disable) {
871 heap_used = _heap->used();
872 }
873 if (sizeness != _verify_size_disable) {
874 guarantee(cl.used() == heap_used,
875 "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
876 label,
877 byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
878 byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
879 }
880 size_t heap_committed = _heap->committed();
881 guarantee(cl.committed() == heap_committed,
882 "%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
883 label,
884 byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
885 byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
886 }
887
888 log_debug(gc)("Safepoint verification finished heap usage verification");
889
890 ShenandoahGeneration* generation;
891 if (_heap->mode()->is_generational()) {
892 generation = _heap->gc_generation();
893 guarantee(generation != nullptr, "Need to know which generation to verify.");
894 shenandoah_assert_generations_reconciled();
895 } else {
896 generation = nullptr;
897 }
898
899 if (generation != nullptr) {
900 ShenandoahHeapLocker lock(_heap->lock());
901
902 switch (remembered) {
903 case _verify_remembered_disable:
904 break;
905 case _verify_remembered_before_marking:
906 log_debug(gc)("Safepoint verification of remembered set at mark");
907 verify_rem_set_before_mark();
908 break;
909 case _verify_remembered_before_updating_references:
910 log_debug(gc)("Safepoint verification of remembered set at update ref");
911 verify_rem_set_before_update_ref();
912 break;
913 case _verify_remembered_after_full_gc:
914 log_debug(gc)("Safepoint verification of remembered set after full gc");
915 verify_rem_set_after_full_gc();
916 break;
917 default:
918 fatal("Unhandled remembered set verification mode");
919 }
920
921 ShenandoahGenerationStatsClosure cl;
922 _heap->heap_region_iterate(&cl);
923
924 if (LogTarget(Debug, gc)::is_enabled()) {
925 ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
926 ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
927 ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
928 }
929 if (sizeness == _verify_size_adjusted_for_padding) {
930 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
931 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
932 ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
933 } else if (sizeness == _verify_size_exact) {
934 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
935 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
936 ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
937 }
938 // else: sizeness must equal _verify_size_disable
939 }
940
941 log_debug(gc)("Safepoint verification finished remembered set verification");
942
943 // Internal heap region checks
944 if (ShenandoahVerifyLevel >= 1) {
945 ShenandoahVerifyHeapRegionClosure cl(label, regions);
946 if (generation != nullptr) {
947 generation->heap_region_iterate(&cl);
948 } else {
949 _heap->heap_region_iterate(&cl);
950 }
951 }
952
953 log_debug(gc)("Safepoint verification finished heap region closure verification");
954
955 OrderAccess::fence();
956
957 if (UseTLAB) {
958 _heap->labs_make_parsable();
959 }
960
961 // Allocate temporary bitmap for storing marking wavefront:
962 _verification_bit_map->clear();
963
964 // Allocate temporary array for storing liveness data
965 ShenandoahLivenessData* ld = NEW_C_HEAP_ARRAY(ShenandoahLivenessData, _heap->num_regions(), mtGC);
966 Copy::fill_to_bytes((void*)ld, _heap->num_regions()*sizeof(ShenandoahLivenessData), 0);
967
968 const VerifyOptions& options = ShenandoahVerifier::VerifyOptions(forwarded, marked, cset, liveness, regions, gcstate);
969
970 // Steps 1-2. Scan root set to get initial reachable set. Finish walking the reachable heap.
971 // This verifies what application can see, since it only cares about reachable objects.
972 size_t count_reachable = 0;
973 if (ShenandoahVerifyLevel >= 2) {
974 ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
975 _heap->workers()->run_task(&task);
976 count_reachable = task.processed();
977 }
978
979 log_debug(gc)("Safepoint verification finished getting initial reachable set");
980
981 // Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
982 // not the application, can see during the region scans. There is no reason to process the objects
983 // that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
984 // before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
985 // what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
986 // version
987
988 size_t count_marked = 0;
989 if (ShenandoahVerifyLevel >= 4 &&
990 (marked == _verify_marked_complete ||
991 marked == _verify_marked_complete_except_references ||
992 marked == _verify_marked_complete_satb_empty)) {
993 guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
994 ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
995 _heap->workers()->run_task(&task);
996 count_marked = task.processed();
997 } else {
998 guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
999 }
1000
1001 log_debug(gc)("Safepoint verification finished walking marked objects");
1002
1003 // Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
1004 // marked objects.
1005
1006 if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
1007 for (size_t i = 0; i < _heap->num_regions(); i++) {
1008 ShenandoahHeapRegion* r = _heap->get_region(i);
1009 if (generation != nullptr && !generation->contains(r)) {
1010 continue;
1011 }
1012
1013 juint verf_live = 0;
1014 if (r->is_humongous()) {
1015 // For humongous objects, test if start region is marked live, and if so,
1016 // all humongous regions in that chain have live data equal to their "used".
1017 juint start_live = Atomic::load(&ld[r->humongous_start_region()->index()]);
1018 if (start_live > 0) {
1019 verf_live = (juint)(r->used() / HeapWordSize);
1020 }
1021 } else {
1022 verf_live = Atomic::load(&ld[r->index()]);
1023 }
1024
1025 size_t reg_live = r->get_live_data_words();
1026 if (reg_live != verf_live) {
1027 stringStream ss;
1028 r->print_on(&ss);
1029 fatal("%s: Live data should match: region-live = " SIZE_FORMAT ", verifier-live = " UINT32_FORMAT "\n%s",
1030 label, reg_live, verf_live, ss.freeze());
1031 }
1032 }
1033 }
1034
1035 log_debug(gc)("Safepoint verification finished accumulation of liveness data");
1036
1037
1038 log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
1039 label, ShenandoahVerifyLevel, count_reachable, count_marked);
1040
1041 FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
1042 }
1043
1044 void ShenandoahVerifier::verify_generic(VerifyOption vo) {
1045 verify_at_safepoint(
1046 "Generic Verification",
1047 _verify_remembered_disable, // do not verify remembered set
1048 _verify_forwarded_allow, // conservatively allow forwarded
1049 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1050 _verify_cset_disable, // cset may be inconsistent
1051 _verify_liveness_disable, // no reliable liveness data
1052 _verify_regions_disable, // no reliable region data
1053 _verify_size_exact, // expect generation and heap sizes to match exactly
1054 _verify_gcstate_disable // no data about gcstate
1055 );
1056 }
1057
1058 void ShenandoahVerifier::verify_before_concmark() {
1059 verify_at_safepoint(
1060 "Before Mark",
1061 _verify_remembered_before_marking,
1062 // verify read-only remembered set from bottom() to top()
1063 _verify_forwarded_none, // UR should have fixed up
1064 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1065 _verify_cset_none, // UR should have fixed this
1066 _verify_liveness_disable, // no reliable liveness data
1067 _verify_regions_notrash, // no trash regions
1068 _verify_size_exact, // expect generation and heap sizes to match exactly
1069 _verify_gcstate_stable // there are no forwarded objects
1070 );
1071 }
1072
1073 void ShenandoahVerifier::verify_after_concmark() {
1074 verify_at_safepoint(
1075 "After Mark",
1076 _verify_remembered_disable, // do not verify remembered set
1077 _verify_forwarded_none, // no forwarded references
1078 _verify_marked_complete_satb_empty,
1079 // bitmaps as precise as we can get, except dangling j.l.r.Refs
1080 _verify_cset_none, // no references to cset anymore
1081 _verify_liveness_complete, // liveness data must be complete here
1082 _verify_regions_disable, // trash regions not yet recycled
1083 _verify_size_exact, // expect generation and heap sizes to match exactly
1084 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1085 );
1086 }
1087
1088 void ShenandoahVerifier::verify_before_evacuation() {
1089 verify_at_safepoint(
1090 "Before Evacuation",
1091 _verify_remembered_disable, // do not verify remembered set
1092 _verify_forwarded_none, // no forwarded references
1093 _verify_marked_complete_except_references, // walk over marked objects too
1094 _verify_cset_disable, // non-forwarded references to cset expected
1095 _verify_liveness_complete, // liveness data must be complete here
1096 _verify_regions_disable, // trash regions not yet recycled
1097 _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
1098 // for promote in place padding
1099 _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
1100 );
1101 }
1102
1103 void ShenandoahVerifier::verify_during_evacuation() {
1104 verify_at_safepoint(
1105 "During Evacuation",
1106 _verify_remembered_disable, // do not verify remembered set
1107 _verify_forwarded_allow, // some forwarded references are allowed
1108 _verify_marked_disable, // walk only roots
1109 _verify_cset_disable, // some cset references are not forwarded yet
1110 _verify_liveness_disable, // liveness data might be already stale after pre-evacs
1111 _verify_regions_disable, // trash regions not yet recycled
1112 _verify_size_disable, // we don't know how much of promote-in-place work has been completed
1113 _verify_gcstate_evacuation // evacuation is in progress
1114 );
1115 }
1116
1117 void ShenandoahVerifier::verify_after_evacuation() {
1118 verify_at_safepoint(
1119 "After Evacuation",
1120 _verify_remembered_disable, // do not verify remembered set
1121 _verify_forwarded_allow, // objects are still forwarded
1122 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1123 _verify_cset_forwarded, // all cset refs are fully forwarded
1124 _verify_liveness_disable, // no reliable liveness data anymore
1125 _verify_regions_notrash, // trash regions have been recycled already
1126 _verify_size_exact, // expect generation and heap sizes to match exactly
1127 _verify_gcstate_forwarded // evacuation produced some forwarded objects
1128 );
1129 }
1130
1131 void ShenandoahVerifier::verify_before_updaterefs() {
1132 verify_at_safepoint(
1133 "Before Updating References",
1134 _verify_remembered_before_updating_references, // verify read-write remembered set
1135 _verify_forwarded_allow, // forwarded references allowed
1136 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1137 _verify_cset_forwarded, // all cset refs are fully forwarded
1138 _verify_liveness_disable, // no reliable liveness data anymore
1139 _verify_regions_notrash, // trash regions have been recycled already
1140 _verify_size_exact, // expect generation and heap sizes to match exactly
1141 _verify_gcstate_updating // evacuation should have produced some forwarded objects
1142 );
1143 }
1144
1145 // We have not yet cleanup (reclaimed) the collection set
1146 void ShenandoahVerifier::verify_after_updaterefs() {
1147 verify_at_safepoint(
1148 "After Updating References",
1149 _verify_remembered_disable, // do not verify remembered set
1150 _verify_forwarded_none, // no forwarded references
1151 _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
1152 _verify_cset_none, // no cset references, all updated
1153 _verify_liveness_disable, // no reliable liveness data anymore
1154 _verify_regions_nocset, // no cset regions, trash regions have appeared
1155 _verify_size_exact, // expect generation and heap sizes to match exactly
1156 _verify_gcstate_stable // update refs had cleaned up forwarded objects
1157 );
1158 }
1159
1160 void ShenandoahVerifier::verify_after_degenerated() {
1161 verify_at_safepoint(
1162 "After Degenerated GC",
1163 _verify_remembered_disable, // do not verify remembered set
1164 _verify_forwarded_none, // all objects are non-forwarded
1165 _verify_marked_complete, // all objects are marked in complete bitmap
1166 _verify_cset_none, // no cset references
1167 _verify_liveness_disable, // no reliable liveness data anymore
1168 _verify_regions_notrash_nocset, // no trash, no cset
1169 _verify_size_exact, // expect generation and heap sizes to match exactly
1170 _verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
1171 );
1172 }
1173
1174 void ShenandoahVerifier::verify_before_fullgc() {
1175 verify_at_safepoint(
1176 "Before Full GC",
1177 _verify_remembered_disable, // do not verify remembered set
1178 _verify_forwarded_allow, // can have forwarded objects
1179 _verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
1180 _verify_cset_disable, // cset might be foobared
1181 _verify_liveness_disable, // no reliable liveness data anymore
1182 _verify_regions_disable, // no reliable region data here
1183 _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
1184 _verify_gcstate_disable // no reliable gcstate data
1185 );
1186 }
1187
1188 void ShenandoahVerifier::verify_after_fullgc() {
1189 verify_at_safepoint(
1190 "After Full GC",
1191 _verify_remembered_after_full_gc, // verify read-write remembered set
1192 _verify_forwarded_none, // all objects are non-forwarded
1193 _verify_marked_complete, // all objects are marked in complete bitmap
1194 _verify_cset_none, // no cset references
1195 _verify_liveness_disable, // no reliable liveness data anymore
1196 _verify_regions_notrash_nocset, // no trash, no cset
1197 _verify_size_exact, // expect generation and heap sizes to match exactly
1198 _verify_gcstate_stable // full gc cleaned up everything
1199 );
1200 }
1201
1202 // TODO: Why this closure does not visit metadata?
1203 class ShenandoahVerifyNoForwared : public BasicOopIterateClosure {
1204 private:
1205 template <class T>
1206 void do_oop_work(T* p) {
1207 T o = RawAccess<>::oop_load(p);
1208 if (!CompressedOops::is_null(o)) {
1209 oop obj = CompressedOops::decode_not_null(o);
1210 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1211 if (obj != fwd) {
1212 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1213 "Verify Roots", "Should not be forwarded", __FILE__, __LINE__);
1214 }
1215 }
1216 }
1217
1218 public:
1219 void do_oop(narrowOop* p) { do_oop_work(p); }
1220 void do_oop(oop* p) { do_oop_work(p); }
1221 };
1222
1223 // TODO: Why this closure does not visit metadata?
1224 class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
1225 private:
1226 template <class T>
1227 void do_oop_work(T* p) {
1228 T o = RawAccess<>::oop_load(p);
1229 if (!CompressedOops::is_null(o)) {
1230 oop obj = CompressedOops::decode_not_null(o);
1231 ShenandoahHeap* heap = ShenandoahHeap::heap();
1232
1233 if (!heap->marking_context()->is_marked_or_old(obj)) {
1234 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1235 "Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
1236 }
1237
1238 if (heap->in_collection_set(obj)) {
1239 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1240 "Verify Roots In To-Space", "Should not be in collection set", __FILE__, __LINE__);
1241 }
1242
1243 oop fwd = ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1244 if (obj != fwd) {
1245 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1246 "Verify Roots In To-Space", "Should not be forwarded", __FILE__, __LINE__);
1247 }
1248 }
1249 }
1250
1251 public:
1252 void do_oop(narrowOop* p) override { do_oop_work(p); }
1253 void do_oop(oop* p) override { do_oop_work(p); }
1254 };
1255
1256 void ShenandoahVerifier::verify_roots_in_to_space() {
1257 ShenandoahVerifyInToSpaceClosure cl;
1258 ShenandoahRootVerifier::roots_do(&cl);
1259 }
1260
1261 void ShenandoahVerifier::verify_roots_no_forwarded() {
1262 ShenandoahVerifyNoForwared cl;
1263 ShenandoahRootVerifier::roots_do(&cl);
1264 }
1265
1266 class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
1267 protected:
1268 bool const _init_mark;
1269 ShenandoahGenerationalHeap* const _heap;
1270 RememberedScanner* const _scanner;
1271
1272 public:
1273 // Argument distinguishes between initial mark or start of update refs verification.
1274 explicit ShenandoahVerifyRemSetClosure(bool init_mark) :
1275 _init_mark(init_mark),
1276 _heap(ShenandoahGenerationalHeap::heap()),
1277 _scanner(_heap->old_generation()->card_scan()) {}
1278
1279 template<class T>
1280 inline void work(T* p) {
1281 T o = RawAccess<>::oop_load(p);
1282 if (!CompressedOops::is_null(o)) {
1283 oop obj = CompressedOops::decode_not_null(o);
1284 if (_heap->is_in_young(obj)) {
1285 size_t card_index = _scanner->card_index_for_addr((HeapWord*) p);
1286 if (_init_mark && !_scanner->is_card_dirty(card_index)) {
1287 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1288 "Verify init-mark remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1289 } else if (!_init_mark && !_scanner->is_write_card_dirty(card_index)) {
1290 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
1291 "Verify init-update-refs remembered set violation", "clean card should be dirty", __FILE__, __LINE__);
1292 }
1293 }
1294 }
1295 }
1296
1297 void do_oop(narrowOop* p) override { work(p); }
1298 void do_oop(oop* p) override { work(p); }
1299 };
1300
1301 void ShenandoahVerifier::help_verify_region_rem_set(ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx, HeapWord* from,
1302 HeapWord* top, HeapWord* registration_watermark, const char* message) {
1303 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1304 ShenandoahVerifyRemSetClosure check_interesting_pointers(false);
1305
1306 HeapWord* obj_addr = from;
1307 if (r->is_humongous_start()) {
1308 oop obj = cast_to_oop(obj_addr);
1309 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1310 size_t card_index = scanner->card_index_for_addr(obj_addr);
1311 // For humongous objects, the typical object is an array, so the following checks may be overkill
1312 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1313 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1314 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1315 obj->oop_iterate(&check_interesting_pointers);
1316 }
1317 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1318 }
1319 // else, this humongous object is not live so no need to verify its internal pointers
1320
1321 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1322 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1323 "object not properly registered", __FILE__, __LINE__);
1324 }
1325 } else if (!r->is_humongous()) {
1326 while (obj_addr < top) {
1327 oop obj = cast_to_oop(obj_addr);
1328 // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
1329 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1330 size_t card_index = scanner->card_index_for_addr(obj_addr);
1331 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1332 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1333 if (!scanner->is_write_card_dirty(card_index) || obj->is_objArray()) {
1334 obj->oop_iterate(&check_interesting_pointers);
1335 }
1336 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1337
1338 if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
1339 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
1340 "object not properly registered", __FILE__, __LINE__);
1341 }
1342 obj_addr += obj->size();
1343 } else {
1344 // This object is not live so we don't verify dirty cards contained therein
1345 HeapWord* tams = ctx->top_at_mark_start(r);
1346 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1347 }
1348 }
1349 }
1350 }
1351
1352 // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
1353 // This examines the read_card_table between bottom() and top() since all PLABS are retired
1354 // before the safepoint for init_mark. Actually, we retire them before update-references and don't
1355 // restore them until the start of evacuation.
1356 void ShenandoahVerifier::verify_rem_set_before_mark() {
1357 shenandoah_assert_safepoint();
1358 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1359
1360 RememberedScanner* scanner = ShenandoahGenerationalHeap::heap()->old_generation()->card_scan();
1361 ShenandoahVerifyRemSetClosure check_interesting_pointers(true);
1362 ShenandoahMarkingContext* ctx;
1363
1364 ShenandoahOldGeneration* old_generation = _heap->old_generation();
1365 log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
1366
1367 shenandoah_assert_generations_reconciled();
1368 if (old_generation->is_mark_complete() || _heap->gc_generation()->is_global()) {
1369 ctx = _heap->complete_marking_context();
1370 } else {
1371 ctx = nullptr;
1372 }
1373
1374 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1375 ShenandoahHeapRegion* r = _heap->get_region(i);
1376 HeapWord* tams = (ctx != nullptr) ? ctx->top_at_mark_start(r) : nullptr;
1377
1378 // TODO: Is this replaceable with call to help_verify_region_rem_set?
1379
1380 if (r->is_old() && r->is_active()) {
1381 HeapWord* obj_addr = r->bottom();
1382 if (r->is_humongous_start()) {
1383 oop obj = cast_to_oop(obj_addr);
1384 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1385 // For humongous objects, the typical object is an array, so the following checks may be overkill
1386 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1387 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1388 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1389 obj->oop_iterate(&check_interesting_pointers);
1390 }
1391 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1392 }
1393 // else, this humongous object is not marked so no need to verify its internal pointers
1394 if (!scanner->verify_registration(obj_addr, ctx)) {
1395 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1396 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1397 }
1398 } else if (!r->is_humongous()) {
1399 HeapWord* top = r->top();
1400 while (obj_addr < top) {
1401 oop obj = cast_to_oop(obj_addr);
1402 // ctx->is_marked() returns true if mark bit set (TAMS not relevant during init mark)
1403 if ((ctx == nullptr) || ctx->is_marked(obj)) {
1404 // For regular objects (not object arrays), if the card holding the start of the object is dirty,
1405 // we do not need to verify that cards spanning interesting pointers within this object are dirty.
1406 if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
1407 obj->oop_iterate(&check_interesting_pointers);
1408 }
1409 // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
1410 if (!scanner->verify_registration(obj_addr, ctx)) {
1411 ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, nullptr, nullptr,
1412 "Verify init-mark remembered set violation", "object not properly registered", __FILE__, __LINE__);
1413 }
1414 obj_addr += obj->size();
1415 } else {
1416 // This object is not live so we don't verify dirty cards contained therein
1417 assert(tams != nullptr, "If object is not live, ctx and tams should be non-null");
1418 obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
1419 }
1420 }
1421 } // else, we ignore humongous continuation region
1422 } // else, this is not an OLD region so we ignore it
1423 } // all regions have been processed
1424 }
1425
1426 void ShenandoahVerifier::verify_rem_set_after_full_gc() {
1427 shenandoah_assert_safepoint();
1428 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1429
1430 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1431 ShenandoahHeapRegion* r = _heap->get_region(i);
1432 if (r->is_old() && !r->is_cset()) {
1433 help_verify_region_rem_set(r, nullptr, r->bottom(), r->top(), r->top(), "Remembered set violation at end of Full GC");
1434 }
1435 }
1436 }
1437
1438 // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
1439 // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
1440 // set should be valid through top. This examines the write_card_table between bottom() and top() because
1441 // all PLABS are retired immediately before the start of update refs.
1442 void ShenandoahVerifier::verify_rem_set_before_update_ref() {
1443 shenandoah_assert_safepoint();
1444 assert(_heap->mode()->is_generational(), "Only verify remembered set for generational operational modes");
1445
1446 ShenandoahMarkingContext* ctx;
1447
1448 shenandoah_assert_generations_reconciled();
1449 if (_heap->old_generation()->is_mark_complete() || _heap->gc_generation()->is_global()) {
1450 ctx = _heap->complete_marking_context();
1451 } else {
1452 ctx = nullptr;
1453 }
1454
1455 for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
1456 ShenandoahHeapRegion* r = _heap->get_region(i);
1457 if (r->is_old() && !r->is_cset()) {
1458 help_verify_region_rem_set(r, ctx, r->bottom(), r->top(), r->get_update_watermark(),
1459 "Remembered set violation at init-update-references");
1460 }
1461 }
1462 }
1463
1464 void ShenandoahVerifier::verify_before_rebuilding_free_set() {
1465 ShenandoahGenerationStatsClosure cl;
1466 _heap->heap_region_iterate(&cl);
1467
1468 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
1469 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
1470 ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
1471 }