1 /*
  2  * Copyright (c) 2016, 2020, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "precompiled.hpp"
 26 #include "code/nmethod.hpp"
 27 #include "gc/g1/g1Allocator.inline.hpp"
 28 #include "gc/g1/g1CollectedHeap.inline.hpp"
 29 #include "gc/g1/g1ConcurrentMarkThread.hpp"
 30 #include "gc/g1/g1HeapVerifier.hpp"
 31 #include "gc/g1/g1Policy.hpp"
 32 #include "gc/g1/g1RemSet.hpp"
 33 #include "gc/g1/g1RootProcessor.hpp"
 34 #include "gc/g1/heapRegion.inline.hpp"
 35 #include "gc/g1/heapRegionRemSet.hpp"
 36 #include "gc/g1/g1StringDedup.hpp"
 37 #include "logging/log.hpp"
 38 #include "logging/logStream.hpp"
 39 #include "memory/iterator.inline.hpp"
 40 #include "memory/resourceArea.hpp"
 41 #include "memory/universe.hpp"
 42 #include "oops/access.inline.hpp"
 43 #include "oops/compressedOops.inline.hpp"
 44 #include "oops/oop.inline.hpp"
 45 #include "runtime/handles.inline.hpp"
 46 
 47 int G1HeapVerifier::_enabled_verification_types = G1HeapVerifier::G1VerifyAll;
 48 
 49 class VerifyRootsClosure: public OopClosure {
 50 private:
 51   G1CollectedHeap* _g1h;
 52   VerifyOption     _vo;
 53   bool             _failures;
 54 public:
 55   // _vo == UsePrevMarking -> use "prev" marking information,
 56   // _vo == UseNextMarking -> use "next" marking information,
 57   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS
 58   VerifyRootsClosure(VerifyOption vo) :
 59     _g1h(G1CollectedHeap::heap()),
 60     _vo(vo),
 61     _failures(false) { }
 62 
 63   bool failures() { return _failures; }
 64 
 65   template <class T> void do_oop_work(T* p) {
 66     T heap_oop = RawAccess<>::oop_load(p);
 67     if (!CompressedOops::is_null(heap_oop)) {
 68       oop obj = CompressedOops::decode_not_null(heap_oop);
 69       if (_g1h->is_obj_dead_cond(obj, _vo)) {
 70         Log(gc, verify) log;
 71         log.error("Root location " PTR_FORMAT " points to dead obj " PTR_FORMAT, p2i(p), p2i(obj));
 72         ResourceMark rm;
 73         LogStream ls(log.error());
 74         obj->print_on(&ls);
 75         _failures = true;
 76       }
 77     }
 78   }
 79 
 80   void do_oop(oop* p)       { do_oop_work(p); }
 81   void do_oop(narrowOop* p) { do_oop_work(p); }
 82 };
 83 
 84 class G1VerifyCodeRootOopClosure: public OopClosure {
 85   G1CollectedHeap* _g1h;
 86   OopClosure* _root_cl;
 87   nmethod* _nm;
 88   VerifyOption _vo;
 89   bool _failures;
 90 
 91   template <class T> void do_oop_work(T* p) {
 92     // First verify that this root is live
 93     _root_cl->do_oop(p);
 94 
 95     if (!G1VerifyHeapRegionCodeRoots) {
 96       // We're not verifying the code roots attached to heap region.
 97       return;
 98     }
 99 
100     // Don't check the code roots during marking verification in a full GC
101     if (_vo == VerifyOption_G1UseFullMarking) {
102       return;
103     }
104 
105     // Now verify that the current nmethod (which contains p) is
106     // in the code root list of the heap region containing the
107     // object referenced by p.
108 
109     T heap_oop = RawAccess<>::oop_load(p);
110     if (!CompressedOops::is_null(heap_oop)) {
111       oop obj = CompressedOops::decode_not_null(heap_oop);
112 
113       // Now fetch the region containing the object
114       HeapRegion* hr = _g1h->heap_region_containing(obj);
115       HeapRegionRemSet* hrrs = hr->rem_set();
116       // Verify that the strong code root list for this region
117       // contains the nmethod
118       if (!hrrs->strong_code_roots_list_contains(_nm)) {
119         log_error(gc, verify)("Code root location " PTR_FORMAT " "
120                               "from nmethod " PTR_FORMAT " not in strong "
121                               "code roots for region [" PTR_FORMAT "," PTR_FORMAT ")",
122                               p2i(p), p2i(_nm), p2i(hr->bottom()), p2i(hr->end()));
123         _failures = true;
124       }
125     }
126   }
127 
128 public:
129   G1VerifyCodeRootOopClosure(G1CollectedHeap* g1h, OopClosure* root_cl, VerifyOption vo):
130     _g1h(g1h), _root_cl(root_cl), _nm(NULL), _vo(vo), _failures(false) {}
131 
132   void do_oop(oop* p) { do_oop_work(p); }
133   void do_oop(narrowOop* p) { do_oop_work(p); }
134 
135   void set_nmethod(nmethod* nm) { _nm = nm; }
136   bool failures() { return _failures; }
137 };
138 
139 class G1VerifyCodeRootBlobClosure: public CodeBlobClosure {
140   G1VerifyCodeRootOopClosure* _oop_cl;
141 
142 public:
143   G1VerifyCodeRootBlobClosure(G1VerifyCodeRootOopClosure* oop_cl):
144     _oop_cl(oop_cl) {}
145 
146   void do_code_blob(CodeBlob* cb) {
147     nmethod* nm = cb->as_nmethod_or_null();
148     if (nm != NULL) {
149       _oop_cl->set_nmethod(nm);
150       nm->oops_do(_oop_cl);
151     }
152   }
153 };
154 
155 class YoungRefCounterClosure : public OopClosure {
156   G1CollectedHeap* _g1h;
157   int              _count;
158  public:
159   YoungRefCounterClosure(G1CollectedHeap* g1h) : _g1h(g1h), _count(0) {}
160   void do_oop(oop* p)       { if (_g1h->is_in_young(*p)) { _count++; } }
161   void do_oop(narrowOop* p) { ShouldNotReachHere(); }
162 
163   int count() { return _count; }
164   void reset_count() { _count = 0; };
165 };
166 
167 class VerifyCLDClosure: public CLDClosure {
168   YoungRefCounterClosure _young_ref_counter_closure;
169   OopClosure *_oop_closure;
170  public:
171   VerifyCLDClosure(G1CollectedHeap* g1h, OopClosure* cl) : _young_ref_counter_closure(g1h), _oop_closure(cl) {}
172   void do_cld(ClassLoaderData* cld) {
173     cld->oops_do(_oop_closure, ClassLoaderData::_claim_none);
174 
175     _young_ref_counter_closure.reset_count();
176     cld->oops_do(&_young_ref_counter_closure, ClassLoaderData::_claim_none);
177     if (_young_ref_counter_closure.count() > 0) {
178       guarantee(cld->has_modified_oops(), "CLD " PTR_FORMAT ", has young %d refs but is not dirty.", p2i(cld), _young_ref_counter_closure.count());
179     }
180   }
181 };
182 
183 class VerifyLivenessOopClosure: public BasicOopIterateClosure {
184   G1CollectedHeap* _g1h;
185   VerifyOption _vo;
186 public:
187   VerifyLivenessOopClosure(G1CollectedHeap* g1h, VerifyOption vo):
188     _g1h(g1h), _vo(vo)
189   { }
190   void do_oop(narrowOop *p) { do_oop_work(p); }
191   void do_oop(      oop *p) { do_oop_work(p); }
192 
193   template <class T> void do_oop_work(T *p) {
194     oop obj = RawAccess<>::oop_load(p);
195     guarantee(obj == NULL || !_g1h->is_obj_dead_cond(obj, _vo),
196               "Dead object referenced by a not dead object");
197   }
198 };
199 
200 class VerifyObjsInRegionClosure: public ObjectClosure {
201 private:
202   G1CollectedHeap* _g1h;
203   size_t _live_bytes;
204   HeapRegion *_hr;
205   VerifyOption _vo;
206 public:
207   // _vo == UsePrevMarking -> use "prev" marking information,
208   // _vo == UseNextMarking -> use "next" marking information,
209   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS.
210   VerifyObjsInRegionClosure(HeapRegion *hr, VerifyOption vo)
211     : _live_bytes(0), _hr(hr), _vo(vo) {
212     _g1h = G1CollectedHeap::heap();
213   }
214   void do_object(oop o) {
215     VerifyLivenessOopClosure isLive(_g1h, _vo);
216     assert(o != NULL, "Huh?");
217     if (!_g1h->is_obj_dead_cond(o, _vo)) {
218       // If the object is alive according to the full gc mark,
219       // then verify that the marking information agrees.
220       // Note we can't verify the contra-positive of the
221       // above: if the object is dead (according to the mark
222       // word), it may not be marked, or may have been marked
223       // but has since became dead, or may have been allocated
224       // since the last marking.
225       if (_vo == VerifyOption_G1UseFullMarking) {
226         guarantee(!_g1h->is_obj_dead(o), "Full GC marking and concurrent mark mismatch");
227       }
228 
229       o->oop_iterate(&isLive);
230       if (!_hr->obj_allocated_since_prev_marking(o)) {
231         size_t obj_size = o->size();    // Make sure we don't overflow
232         _live_bytes += (obj_size * HeapWordSize);
233       }
234     }
235   }
236   size_t live_bytes() { return _live_bytes; }
237 };
238 
239 class VerifyArchiveOopClosure: public BasicOopIterateClosure {
240   HeapRegion* _hr;
241 public:
242   VerifyArchiveOopClosure(HeapRegion *hr)
243     : _hr(hr) { }
244   void do_oop(narrowOop *p) { do_oop_work(p); }
245   void do_oop(      oop *p) { do_oop_work(p); }
246 
247   template <class T> void do_oop_work(T *p) {
248     oop obj = RawAccess<>::oop_load(p);
249 
250     if (_hr->is_open_archive()) {
251       guarantee(obj == NULL || G1ArchiveAllocator::is_archived_object(obj),
252                 "Archive object at " PTR_FORMAT " references a non-archive object at " PTR_FORMAT,
253                 p2i(p), p2i(obj));
254     } else {
255       assert(_hr->is_closed_archive(), "should be closed archive region");
256       guarantee(obj == NULL || G1ArchiveAllocator::is_closed_archive_object(obj),
257                 "Archive object at " PTR_FORMAT " references a non-archive object at " PTR_FORMAT,
258                 p2i(p), p2i(obj));
259     }
260   }
261 };
262 
263 class VerifyObjectInArchiveRegionClosure: public ObjectClosure {
264   HeapRegion* _hr;
265 public:
266   VerifyObjectInArchiveRegionClosure(HeapRegion *hr, bool verbose)
267     : _hr(hr) { }
268   // Verify that all object pointers are to archive regions.
269   void do_object(oop o) {
270     VerifyArchiveOopClosure checkOop(_hr);
271     assert(o != NULL, "Should not be here for NULL oops");
272     o->oop_iterate(&checkOop);
273   }
274 };
275 
276 // Should be only used at CDS dump time
277 class VerifyReadyForArchivingRegionClosure : public HeapRegionClosure {
278   bool _seen_free;
279   bool _has_holes;
280   bool _has_unexpected_holes;
281   bool _has_humongous;
282 public:
283   bool has_holes() {return _has_holes;}
284   bool has_unexpected_holes() {return _has_unexpected_holes;}
285   bool has_humongous() {return _has_humongous;}
286 
287   VerifyReadyForArchivingRegionClosure() : HeapRegionClosure() {
288     _seen_free = false;
289     _has_holes = false;
290     _has_unexpected_holes = false;
291     _has_humongous = false;
292   }
293   virtual bool do_heap_region(HeapRegion* hr) {
294     const char* hole = "";
295 
296     if (hr->is_free()) {
297       _seen_free = true;
298     } else {
299       if (_seen_free) {
300         _has_holes = true;
301         if (hr->is_humongous()) {
302           hole = " hole";
303         } else {
304           _has_unexpected_holes = true;
305           hole = " hole **** unexpected ****";
306         }
307       }
308     }
309     if (hr->is_humongous()) {
310       _has_humongous = true;
311     }
312     log_info(gc, region, cds)("HeapRegion " INTPTR_FORMAT " %s%s", p2i(hr->bottom()), hr->get_type_str(), hole);
313     return false;
314   }
315 };
316 
317 // We want all used regions to be moved to the bottom-end of the heap, so we have
318 // a contiguous range of free regions at the top end of the heap. This way, we can
319 // avoid fragmentation while allocating the archive regions.
320 //
321 // Before calling this, a full GC should have been executed with a single worker thread,
322 // so that no old regions would be moved to the middle of the heap.
323 void G1HeapVerifier::verify_ready_for_archiving() {
324   VerifyReadyForArchivingRegionClosure cl;
325   G1CollectedHeap::heap()->heap_region_iterate(&cl);
326   if (cl.has_holes()) {
327     log_warning(gc, verify)("All free regions should be at the top end of the heap, but"
328                             " we found holes. This is probably caused by (unmovable) humongous"
329                             " allocations or active GCLocker, and may lead to fragmentation while"
330                             " writing archive heap memory regions.");
331   }
332   if (cl.has_humongous()) {
333     log_warning(gc, verify)("(Unmovable) humongous regions have been found and"
334                             " may lead to fragmentation while"
335                             " writing archive heap memory regions.");
336   }
337 }
338 
339 class VerifyArchivePointerRegionClosure: public HeapRegionClosure {
340   virtual bool do_heap_region(HeapRegion* r) {
341    if (r->is_archive()) {
342       VerifyObjectInArchiveRegionClosure verify_oop_pointers(r, false);
343       r->object_iterate(&verify_oop_pointers);
344     }
345     return false;
346   }
347 };
348 
349 void G1HeapVerifier::verify_archive_regions() {
350   G1CollectedHeap*  g1h = G1CollectedHeap::heap();
351   VerifyArchivePointerRegionClosure cl;
352   g1h->heap_region_iterate(&cl);
353 }
354 
355 class VerifyRegionClosure: public HeapRegionClosure {
356 private:
357   bool             _par;
358   VerifyOption     _vo;
359   bool             _failures;
360 public:
361   // _vo == UsePrevMarking -> use "prev" marking information,
362   // _vo == UseNextMarking -> use "next" marking information,
363   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS
364   VerifyRegionClosure(bool par, VerifyOption vo)
365     : _par(par),
366       _vo(vo),
367       _failures(false) {}
368 
369   bool failures() {
370     return _failures;
371   }
372 
373   bool do_heap_region(HeapRegion* r) {
374     guarantee(!r->has_index_in_opt_cset(), "Region %u still has opt collection set index %u", r->hrm_index(), r->index_in_opt_cset());
375     guarantee(!r->is_young() || r->rem_set()->is_complete(), "Remembered set for Young region %u must be complete, is %s", r->hrm_index(), r->rem_set()->get_state_str());
376     // Humongous and old regions regions might be of any state, so can't check here.
377     guarantee(!r->is_free() || !r->rem_set()->is_tracked(), "Remembered set for free region %u must be untracked, is %s", r->hrm_index(), r->rem_set()->get_state_str());
378     // Verify that the continues humongous regions' remembered set state matches the
379     // one from the starts humongous region.
380     if (r->is_continues_humongous()) {
381       if (r->rem_set()->get_state_str() != r->humongous_start_region()->rem_set()->get_state_str()) {
382          log_error(gc, verify)("Remset states differ: Region %u (%s) remset %s with starts region %u (%s) remset %s",
383                                r->hrm_index(),
384                                r->get_short_type_str(),
385                                r->rem_set()->get_state_str(),
386                                r->humongous_start_region()->hrm_index(),
387                                r->humongous_start_region()->get_short_type_str(),
388                                r->humongous_start_region()->rem_set()->get_state_str());
389          _failures = true;
390       }
391     }
392     // For archive regions, verify there are no heap pointers to
393     // non-pinned regions. For all others, verify liveness info.
394     if (r->is_closed_archive()) {
395       VerifyObjectInArchiveRegionClosure verify_oop_pointers(r, false);
396       r->object_iterate(&verify_oop_pointers);
397       return true;
398     } else if (r->is_open_archive()) {
399       VerifyObjsInRegionClosure verify_open_archive_oop(r, _vo);
400       r->object_iterate(&verify_open_archive_oop);
401       return true;
402     } else if (!r->is_continues_humongous()) {
403       bool failures = false;
404       r->verify(_vo, &failures);
405       if (failures) {
406         _failures = true;
407       } else if (!r->is_starts_humongous()) {
408         VerifyObjsInRegionClosure not_dead_yet_cl(r, _vo);
409         r->object_iterate(&not_dead_yet_cl);
410         if (_vo != VerifyOption_G1UseNextMarking) {
411           if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {
412             log_error(gc, verify)("[" PTR_FORMAT "," PTR_FORMAT "] max_live_bytes " SIZE_FORMAT " < calculated " SIZE_FORMAT,
413                                   p2i(r->bottom()), p2i(r->end()), r->max_live_bytes(), not_dead_yet_cl.live_bytes());
414             _failures = true;
415           }
416         } else {
417           // When vo == UseNextMarking we cannot currently do a sanity
418           // check on the live bytes as the calculation has not been
419           // finalized yet.
420         }
421       }
422     }
423     return false; // stop the region iteration if we hit a failure
424   }
425 };
426 
427 // This is the task used for parallel verification of the heap regions
428 
429 class G1ParVerifyTask: public AbstractGangTask {
430 private:
431   G1CollectedHeap*  _g1h;
432   VerifyOption      _vo;
433   bool              _failures;
434   HeapRegionClaimer _hrclaimer;
435 
436 public:
437   // _vo == UsePrevMarking -> use "prev" marking information,
438   // _vo == UseNextMarking -> use "next" marking information,
439   // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS
440   G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) :
441       AbstractGangTask("Parallel verify task"),
442       _g1h(g1h),
443       _vo(vo),
444       _failures(false),
445       _hrclaimer(g1h->workers()->active_workers()) {}
446 
447   bool failures() {
448     return _failures;
449   }
450 
451   void work(uint worker_id) {
452     VerifyRegionClosure blk(true, _vo);
453     _g1h->heap_region_par_iterate_from_worker_offset(&blk, &_hrclaimer, worker_id);
454     if (blk.failures()) {
455       _failures = true;
456     }
457   }
458 };
459 
460 void G1HeapVerifier::enable_verification_type(G1VerifyType type) {
461   // First enable will clear _enabled_verification_types.
462   if (_enabled_verification_types == G1VerifyAll) {
463     _enabled_verification_types = type;
464   } else {
465     _enabled_verification_types |= type;
466   }
467 }
468 
469 bool G1HeapVerifier::should_verify(G1VerifyType type) {
470   return (_enabled_verification_types & type) == type;
471 }
472 
473 void G1HeapVerifier::verify(VerifyOption vo) {
474   if (!SafepointSynchronize::is_at_safepoint()) {
475     log_info(gc, verify)("Skipping verification. Not at safepoint.");
476   }
477 
478   assert(Thread::current()->is_VM_thread(),
479          "Expected to be executed serially by the VM thread at this point");
480 
481   log_debug(gc, verify)("Roots");
482   VerifyRootsClosure rootsCl(vo);
483   VerifyCLDClosure cldCl(_g1h, &rootsCl);
484 
485   // We apply the relevant closures to all the oops in the
486   // system dictionary, class loader data graph, the string table
487   // and the nmethods in the code cache.
488   G1VerifyCodeRootOopClosure codeRootsCl(_g1h, &rootsCl, vo);
489   G1VerifyCodeRootBlobClosure blobsCl(&codeRootsCl);
490 
491   {
492     G1RootProcessor root_processor(_g1h, 1);
493     root_processor.process_all_roots(&rootsCl, &cldCl, &blobsCl);
494   }
495 
496   bool failures = rootsCl.failures() || codeRootsCl.failures();
497 
498   if (!_g1h->policy()->collector_state()->in_full_gc()) {
499     // If we're verifying during a full GC then the region sets
500     // will have been torn down at the start of the GC. Therefore
501     // verifying the region sets will fail. So we only verify
502     // the region sets when not in a full GC.
503     log_debug(gc, verify)("HeapRegionSets");
504     verify_region_sets();
505   }
506 
507   log_debug(gc, verify)("HeapRegions");
508   if (GCParallelVerificationEnabled && ParallelGCThreads > 1) {
509 
510     G1ParVerifyTask task(_g1h, vo);
511     _g1h->workers()->run_task(&task);
512     if (task.failures()) {
513       failures = true;
514     }
515 
516   } else {
517     VerifyRegionClosure blk(false, vo);
518     _g1h->heap_region_iterate(&blk);
519     if (blk.failures()) {
520       failures = true;
521     }
522   }
523 
524   if (G1StringDedup::is_enabled()) {
525     log_debug(gc, verify)("StrDedup");
526     G1StringDedup::verify();
527   }
528 
529   if (failures) {
530     log_error(gc, verify)("Heap after failed verification (kind %d):", vo);
531     // It helps to have the per-region information in the output to
532     // help us track down what went wrong. This is why we call
533     // print_extended_on() instead of print_on().
534     Log(gc, verify) log;
535     ResourceMark rm;
536     LogStream ls(log.error());
537     _g1h->print_extended_on(&ls);
538   }
539   guarantee(!failures, "there should not have been any failures");
540 }
541 
542 // Heap region set verification
543 
544 class VerifyRegionListsClosure : public HeapRegionClosure {
545 private:
546   HeapRegionSet*   _old_set;
547   HeapRegionSet*   _archive_set;
548   HeapRegionSet*   _humongous_set;
549   HeapRegionManager* _hrm;
550 
551 public:
552   uint _old_count;
553   uint _archive_count;
554   uint _humongous_count;
555   uint _free_count;
556 
557   VerifyRegionListsClosure(HeapRegionSet* old_set,
558                            HeapRegionSet* archive_set,
559                            HeapRegionSet* humongous_set,
560                            HeapRegionManager* hrm) :
561     _old_set(old_set), _archive_set(archive_set), _humongous_set(humongous_set), _hrm(hrm),
562     _old_count(), _archive_count(), _humongous_count(), _free_count(){ }
563 
564   bool do_heap_region(HeapRegion* hr) {
565     if (hr->is_young()) {
566       // TODO
567     } else if (hr->is_humongous()) {
568       assert(hr->containing_set() == _humongous_set, "Heap region %u is humongous but not in humongous set.", hr->hrm_index());
569       _humongous_count++;
570     } else if (hr->is_empty()) {
571       assert(_hrm->is_free(hr), "Heap region %u is empty but not on the free list.", hr->hrm_index());
572       _free_count++;
573     } else if (hr->is_archive()) {
574       assert(hr->containing_set() == _archive_set, "Heap region %u is archive but not in the archive set.", hr->hrm_index());
575       _archive_count++;
576     } else if (hr->is_old()) {
577       assert(hr->containing_set() == _old_set, "Heap region %u is old but not in the old set.", hr->hrm_index());
578       _old_count++;
579     } else {
580       // There are no other valid region types. Check for one invalid
581       // one we can identify: pinned without old or humongous set.
582       assert(!hr->is_pinned(), "Heap region %u is pinned but not old (archive) or humongous.", hr->hrm_index());
583       ShouldNotReachHere();
584     }
585     return false;
586   }
587 
588   void verify_counts(HeapRegionSet* old_set, HeapRegionSet* archive_set, HeapRegionSet* humongous_set, HeapRegionManager* free_list) {
589     guarantee(old_set->length() == _old_count, "Old set count mismatch. Expected %u, actual %u.", old_set->length(), _old_count);
590     guarantee(archive_set->length() == _archive_count, "Archive set count mismatch. Expected %u, actual %u.", archive_set->length(), _archive_count);
591     guarantee(humongous_set->length() == _humongous_count, "Hum set count mismatch. Expected %u, actual %u.", humongous_set->length(), _humongous_count);
592     guarantee(free_list->num_free_regions() == _free_count, "Free list count mismatch. Expected %u, actual %u.", free_list->num_free_regions(), _free_count);
593   }
594 };
595 
596 void G1HeapVerifier::verify_region_sets() {
597   assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
598 
599   // First, check the explicit lists.
600   _g1h->_hrm->verify();
601 
602   // Finally, make sure that the region accounting in the lists is
603   // consistent with what we see in the heap.
604 
605   VerifyRegionListsClosure cl(&_g1h->_old_set, &_g1h->_archive_set, &_g1h->_humongous_set, _g1h->_hrm);
606   _g1h->heap_region_iterate(&cl);
607   cl.verify_counts(&_g1h->_old_set, &_g1h->_archive_set, &_g1h->_humongous_set, _g1h->_hrm);
608 }
609 
610 void G1HeapVerifier::prepare_for_verify() {
611   if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
612     _g1h->ensure_parsability(false);
613   }
614 }
615 
616 double G1HeapVerifier::verify(G1VerifyType type, VerifyOption vo, const char* msg) {
617   double verify_time_ms = 0.0;
618 
619   if (should_verify(type) && _g1h->total_collections() >= VerifyGCStartAt) {
620     double verify_start = os::elapsedTime();
621     prepare_for_verify();
622     Universe::verify(vo, msg);
623     verify_time_ms = (os::elapsedTime() - verify_start) * 1000;
624   }
625 
626   return verify_time_ms;
627 }
628 
629 void G1HeapVerifier::verify_before_gc(G1VerifyType type) {
630   if (VerifyBeforeGC) {
631     double verify_time_ms = verify(type, VerifyOption_G1UsePrevMarking, "Before GC");
632     _g1h->phase_times()->record_verify_before_time_ms(verify_time_ms);
633   }
634 }
635 
636 void G1HeapVerifier::verify_after_gc(G1VerifyType type) {
637   if (VerifyAfterGC) {
638     double verify_time_ms = verify(type, VerifyOption_G1UsePrevMarking, "After GC");
639     _g1h->phase_times()->record_verify_after_time_ms(verify_time_ms);
640   }
641 }
642 
643 
644 #ifndef PRODUCT
645 class G1VerifyCardTableCleanup: public HeapRegionClosure {
646   G1HeapVerifier* _verifier;
647 public:
648   G1VerifyCardTableCleanup(G1HeapVerifier* verifier)
649     : _verifier(verifier) { }
650   virtual bool do_heap_region(HeapRegion* r) {
651     if (r->is_survivor()) {
652       _verifier->verify_dirty_region(r);
653     } else {
654       _verifier->verify_not_dirty_region(r);
655     }
656     return false;
657   }
658 };
659 
660 void G1HeapVerifier::verify_card_table_cleanup() {
661   if (G1VerifyCTCleanup || VerifyAfterGC) {
662     G1VerifyCardTableCleanup cleanup_verifier(this);
663     _g1h->heap_region_iterate(&cleanup_verifier);
664   }
665 }
666 
667 void G1HeapVerifier::verify_not_dirty_region(HeapRegion* hr) {
668   // All of the region should be clean.
669   G1CardTable* ct = _g1h->card_table();
670   MemRegion mr(hr->bottom(), hr->end());
671   ct->verify_not_dirty_region(mr);
672 }
673 
674 void G1HeapVerifier::verify_dirty_region(HeapRegion* hr) {
675   // We cannot guarantee that [bottom(),end()] is dirty.  Threads
676   // dirty allocated blocks as they allocate them. The thread that
677   // retires each region and replaces it with a new one will do a
678   // maximal allocation to fill in [pre_dummy_top(),end()] but will
679   // not dirty that area (one less thing to have to do while holding
680   // a lock). So we can only verify that [bottom(),pre_dummy_top()]
681   // is dirty.
682   G1CardTable* ct = _g1h->card_table();
683   MemRegion mr(hr->bottom(), hr->pre_dummy_top());
684   if (hr->is_young()) {
685     ct->verify_g1_young_region(mr);
686   } else {
687     ct->verify_dirty_region(mr);
688   }
689 }
690 
691 class G1VerifyDirtyYoungListClosure : public HeapRegionClosure {
692 private:
693   G1HeapVerifier* _verifier;
694 public:
695   G1VerifyDirtyYoungListClosure(G1HeapVerifier* verifier) : HeapRegionClosure(), _verifier(verifier) { }
696   virtual bool do_heap_region(HeapRegion* r) {
697     _verifier->verify_dirty_region(r);
698     return false;
699   }
700 };
701 
702 void G1HeapVerifier::verify_dirty_young_regions() {
703   G1VerifyDirtyYoungListClosure cl(this);
704   _g1h->collection_set()->iterate(&cl);
705 }
706 
707 bool G1HeapVerifier::verify_no_bits_over_tams(const char* bitmap_name, const G1CMBitMap* const bitmap,
708                                                HeapWord* tams, HeapWord* end) {
709   guarantee(tams <= end,
710             "tams: " PTR_FORMAT " end: " PTR_FORMAT, p2i(tams), p2i(end));
711   HeapWord* result = bitmap->get_next_marked_addr(tams, end);
712   if (result < end) {
713     log_error(gc, verify)("## wrong marked address on %s bitmap: " PTR_FORMAT, bitmap_name, p2i(result));
714     log_error(gc, verify)("## %s tams: " PTR_FORMAT " end: " PTR_FORMAT, bitmap_name, p2i(tams), p2i(end));
715     return false;
716   }
717   return true;
718 }
719 
720 bool G1HeapVerifier::verify_bitmaps(const char* caller, HeapRegion* hr) {
721   const G1CMBitMap* const prev_bitmap = _g1h->concurrent_mark()->prev_mark_bitmap();
722   const G1CMBitMap* const next_bitmap = _g1h->concurrent_mark()->next_mark_bitmap();
723 
724   HeapWord* ptams  = hr->prev_top_at_mark_start();
725   HeapWord* ntams  = hr->next_top_at_mark_start();
726   HeapWord* end    = hr->end();
727 
728   bool res_p = verify_no_bits_over_tams("prev", prev_bitmap, ptams, end);
729 
730   bool res_n = true;
731   // We cannot verify the next bitmap while we are about to clear it.
732   if (!_g1h->collector_state()->clearing_next_bitmap()) {
733     res_n = verify_no_bits_over_tams("next", next_bitmap, ntams, end);
734   }
735   if (!res_p || !res_n) {
736     log_error(gc, verify)("#### Bitmap verification failed for " HR_FORMAT, HR_FORMAT_PARAMS(hr));
737     log_error(gc, verify)("#### Caller: %s", caller);
738     return false;
739   }
740   return true;
741 }
742 
743 void G1HeapVerifier::check_bitmaps(const char* caller, HeapRegion* hr) {
744   if (!G1VerifyBitmaps) {
745     return;
746   }
747 
748   guarantee(verify_bitmaps(caller, hr), "bitmap verification");
749 }
750 
751 class G1VerifyBitmapClosure : public HeapRegionClosure {
752 private:
753   const char* _caller;
754   G1HeapVerifier* _verifier;
755   bool _failures;
756 
757 public:
758   G1VerifyBitmapClosure(const char* caller, G1HeapVerifier* verifier) :
759     _caller(caller), _verifier(verifier), _failures(false) { }
760 
761   bool failures() { return _failures; }
762 
763   virtual bool do_heap_region(HeapRegion* hr) {
764     bool result = _verifier->verify_bitmaps(_caller, hr);
765     if (!result) {
766       _failures = true;
767     }
768     return false;
769   }
770 };
771 
772 void G1HeapVerifier::check_bitmaps(const char* caller) {
773   if (!G1VerifyBitmaps) {
774     return;
775   }
776 
777   G1VerifyBitmapClosure cl(caller, this);
778   _g1h->heap_region_iterate(&cl);
779   guarantee(!cl.failures(), "bitmap verification");
780 }
781 
782 class G1CheckRegionAttrTableClosure : public HeapRegionClosure {
783 private:
784   bool _failures;
785 
786 public:
787   G1CheckRegionAttrTableClosure() : HeapRegionClosure(), _failures(false) { }
788 
789   virtual bool do_heap_region(HeapRegion* hr) {
790     uint i = hr->hrm_index();
791     G1HeapRegionAttr region_attr = (G1HeapRegionAttr) G1CollectedHeap::heap()->_region_attr.get_by_index(i);
792     if (hr->is_humongous()) {
793       if (hr->in_collection_set()) {
794         log_error(gc, verify)("## humongous region %u in CSet", i);
795         _failures = true;
796         return true;
797       }
798       if (region_attr.is_in_cset()) {
799         log_error(gc, verify)("## inconsistent region attr type %s for humongous region %u", region_attr.get_type_str(), i);
800         _failures = true;
801         return true;
802       }
803       if (hr->is_continues_humongous() && region_attr.is_humongous()) {
804         log_error(gc, verify)("## inconsistent region attr type %s for continues humongous region %u", region_attr.get_type_str(), i);
805         _failures = true;
806         return true;
807       }
808     } else {
809       if (region_attr.is_humongous()) {
810         log_error(gc, verify)("## inconsistent region attr type %s for non-humongous region %u", region_attr.get_type_str(), i);
811         _failures = true;
812         return true;
813       }
814       if (hr->in_collection_set() != region_attr.is_in_cset()) {
815         log_error(gc, verify)("## in CSet %d / region attr type %s inconsistency for region %u",
816                              hr->in_collection_set(), region_attr.get_type_str(), i);
817         _failures = true;
818         return true;
819       }
820       if (region_attr.is_in_cset()) {
821         if (hr->is_archive()) {
822           log_error(gc, verify)("## is_archive in collection set for region %u", i);
823           _failures = true;
824           return true;
825         }
826         if (hr->is_young() != (region_attr.is_young())) {
827           log_error(gc, verify)("## is_young %d / region attr type %s inconsistency for region %u",
828                                hr->is_young(), region_attr.get_type_str(), i);
829           _failures = true;
830           return true;
831         }
832         if (hr->is_old() != (region_attr.is_old())) {
833           log_error(gc, verify)("## is_old %d / region attr type %s inconsistency for region %u",
834                                hr->is_old(), region_attr.get_type_str(), i);
835           _failures = true;
836           return true;
837         }
838       }
839     }
840     return false;
841   }
842 
843   bool failures() const { return _failures; }
844 };
845 
846 bool G1HeapVerifier::check_region_attr_table() {
847   G1CheckRegionAttrTableClosure cl;
848   _g1h->_hrm->iterate(&cl);
849   return !cl.failures();
850 }
851 #endif // PRODUCT