/*

 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "code/nmethod.hpp"

#include "gc/g1/g1Allocator.inline.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/g1ConcurrentMarkThread.hpp"

#include "gc/g1/g1HeapVerifier.hpp"

#include "gc/g1/g1Policy.hpp"

#include "gc/g1/g1RemSet.hpp"

#include "gc/g1/g1RootProcessor.hpp"

#include "gc/g1/heapRegion.inline.hpp"

#include "gc/g1/heapRegionRemSet.hpp"

#include "gc/g1/g1StringDedup.hpp"

#include "logging/log.hpp"

#include "logging/logStream.hpp"

#include "memory/iterator.inline.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "oops/access.inline.hpp"

#include "oops/compressedOops.inline.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/handles.inline.hpp"

int G1HeapVerifier::_enabled_verification_types = G1HeapVerifier::G1VerifyAll;

class VerifyRootsClosure: public OopClosure {

private:

  G1CollectedHeap* _g1h;

  VerifyOption     _vo;

  bool             _failures;

public:

  // _vo == UsePrevMarking -> use "prev" marking information,

  // _vo == UseNextMarking -> use "next" marking information,

  // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS

  VerifyRootsClosure(VerifyOption vo) :

    _g1h(G1CollectedHeap::heap()),

    _vo(vo),

    _failures(false) { }

  bool failures() { return _failures; }

  template <class T> void do_oop_work(T* p) {

    T heap_oop = RawAccess<>::oop_load(p);

    if (!CompressedOops::is_null(heap_oop)) {

      oop obj = CompressedOops::decode_not_null(heap_oop);

      if (_g1h->is_obj_dead_cond(obj, _vo)) {

        Log(gc, verify) log;

        log.error("Root location " PTR_FORMAT " points to dead obj " PTR_FORMAT, p2i(p), p2i(obj));

        ResourceMark rm;

        LogStream ls(log.error());

        obj->print_on(&ls);

        _failures = true;

      }

    }

  }

  void do_oop(oop* p)       { do_oop_work(p); }

  void do_oop(narrowOop* p) { do_oop_work(p); }

};

class G1VerifyCodeRootOopClosure: public OopClosure {

  G1CollectedHeap* _g1h;

  OopClosure* _root_cl;

  nmethod* _nm;

  VerifyOption _vo;

  bool _failures;

  template <class T> void do_oop_work(T* p) {

    // First verify that this root is live

    _root_cl->do_oop(p);

    if (!G1VerifyHeapRegionCodeRoots) {

      // We're not verifying the code roots attached to heap region.

      return;

    }

    // Don't check the code roots during marking verification in a full GC

    if (_vo == VerifyOption_G1UseFullMarking) {

      return;

    }

    // Now verify that the current nmethod (which contains p) is

    // in the code root list of the heap region containing the

    // object referenced by p.

    T heap_oop = RawAccess<>::oop_load(p);

    if (!CompressedOops::is_null(heap_oop)) {

      oop obj = CompressedOops::decode_not_null(heap_oop);

      // Now fetch the region containing the object

      HeapRegion* hr = _g1h->heap_region_containing(obj);

      HeapRegionRemSet* hrrs = hr->rem_set();

      // Verify that the strong code root list for this region

      // contains the nmethod

      if (!hrrs->strong_code_roots_list_contains(_nm)) {

        log_error(gc, verify)("Code root location " PTR_FORMAT " "

                              "from nmethod " PTR_FORMAT " not in strong "

                              "code roots for region [" PTR_FORMAT "," PTR_FORMAT ")",

                              p2i(p), p2i(_nm), p2i(hr->bottom()), p2i(hr->end()));

        _failures = true;

      }

    }

  }

public:

  G1VerifyCodeRootOopClosure(G1CollectedHeap* g1h, OopClosure* root_cl, VerifyOption vo):

    _g1h(g1h), _root_cl(root_cl), _nm(NULL), _vo(vo), _failures(false) {}

  void do_oop(oop* p) { do_oop_work(p); }

  void do_oop(narrowOop* p) { do_oop_work(p); }

  void set_nmethod(nmethod* nm) { _nm = nm; }

  bool failures() { return _failures; }

};

class G1VerifyCodeRootBlobClosure: public CodeBlobClosure {

  G1VerifyCodeRootOopClosure* _oop_cl;

public:

  G1VerifyCodeRootBlobClosure(G1VerifyCodeRootOopClosure* oop_cl):

    _oop_cl(oop_cl) {}

  void do_code_blob(CodeBlob* cb) {

    nmethod* nm = cb->as_nmethod_or_null();

    if (nm != NULL) {

      _oop_cl->set_nmethod(nm);

      nm->oops_do(_oop_cl);

    }

  }

};

class YoungRefCounterClosure : public OopClosure {

  G1CollectedHeap* _g1h;

  int              _count;

 public:

  YoungRefCounterClosure(G1CollectedHeap* g1h) : _g1h(g1h), _count(0) {}

  void do_oop(oop* p)       { if (_g1h->is_in_young(*p)) { _count++; } }

  void do_oop(narrowOop* p) { ShouldNotReachHere(); }

  int count() { return _count; }

  void reset_count() { _count = 0; };

};

class VerifyCLDClosure: public CLDClosure {

  YoungRefCounterClosure _young_ref_counter_closure;

  OopClosure *_oop_closure;

 public:

  VerifyCLDClosure(G1CollectedHeap* g1h, OopClosure* cl) : _young_ref_counter_closure(g1h), _oop_closure(cl) {}

  void do_cld(ClassLoaderData* cld) {

    cld->oops_do(_oop_closure, ClassLoaderData::_claim_none);

    _young_ref_counter_closure.reset_count();

    cld->oops_do(&_young_ref_counter_closure, ClassLoaderData::_claim_none);

    if (_young_ref_counter_closure.count() > 0) {

      guarantee(cld->has_modified_oops(), "CLD " PTR_FORMAT ", has young %d refs but is not dirty.", p2i(cld), _young_ref_counter_closure.count());

    }

  }

};

class VerifyLivenessOopClosure: public BasicOopIterateClosure {

  G1CollectedHeap* _g1h;

  VerifyOption _vo;

public:

  VerifyLivenessOopClosure(G1CollectedHeap* g1h, VerifyOption vo):

    _g1h(g1h), _vo(vo)

  { }

  void do_oop(narrowOop *p) { do_oop_work(p); }

  void do_oop(      oop *p) { do_oop_work(p); }

  template <class T> void do_oop_work(T *p) {

    oop obj = RawAccess<>::oop_load(p);

    guarantee(obj == NULL || !_g1h->is_obj_dead_cond(obj, _vo),

              "Dead object referenced by a not dead object");

  }

};

class VerifyObjsInRegionClosure: public ObjectClosure {

private:

  G1CollectedHeap* _g1h;

  size_t _live_bytes;

  HeapRegion *_hr;

  VerifyOption _vo;

public:

  // _vo == UsePrevMarking -> use "prev" marking information,

  // _vo == UseNextMarking -> use "next" marking information,

  // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS.

  VerifyObjsInRegionClosure(HeapRegion *hr, VerifyOption vo)

    : _live_bytes(0), _hr(hr), _vo(vo) {

    _g1h = G1CollectedHeap::heap();

  }

  void do_object(oop o) {

    VerifyLivenessOopClosure isLive(_g1h, _vo);

    assert(o != NULL, "Huh?");

    if (!_g1h->is_obj_dead_cond(o, _vo)) {

      // If the object is alive according to the full gc mark,

      // then verify that the marking information agrees.

      // Note we can't verify the contra-positive of the

      // above: if the object is dead (according to the mark

      // word), it may not be marked, or may have been marked

      // but has since became dead, or may have been allocated

      // since the last marking.

      if (_vo == VerifyOption_G1UseFullMarking) {

        guarantee(!_g1h->is_obj_dead(o), "Full GC marking and concurrent mark mismatch");

      }

      o->oop_iterate(&isLive);

      if (!_hr->obj_allocated_since_prev_marking(o)) {

        size_t obj_size = o->size();    // Make sure we don't overflow

        _live_bytes += (obj_size * HeapWordSize);

      }

    }

  }

  size_t live_bytes() { return _live_bytes; }

};

class VerifyArchiveOopClosure: public BasicOopIterateClosure {

  HeapRegion* _hr;

public:

  VerifyArchiveOopClosure(HeapRegion *hr)

    : _hr(hr) { }

  void do_oop(narrowOop *p) { do_oop_work(p); }

  void do_oop(      oop *p) { do_oop_work(p); }

  template <class T> void do_oop_work(T *p) {

    oop obj = RawAccess<>::oop_load(p);

    if (_hr->is_open_archive()) {

      guarantee(obj == NULL || G1ArchiveAllocator::is_archived_object(obj),

                "Archive object at " PTR_FORMAT " references a non-archive object at " PTR_FORMAT,

                p2i(p), p2i(obj));

    } else {

      assert(_hr->is_closed_archive(), "should be closed archive region");

      guarantee(obj == NULL || G1ArchiveAllocator::is_closed_archive_object(obj),

                "Archive object at " PTR_FORMAT " references a non-archive object at " PTR_FORMAT,

                p2i(p), p2i(obj));

    }

  }

};

class VerifyObjectInArchiveRegionClosure: public ObjectClosure {

  HeapRegion* _hr;

public:

  VerifyObjectInArchiveRegionClosure(HeapRegion *hr, bool verbose)

    : _hr(hr) { }

  // Verify that all object pointers are to archive regions.

  void do_object(oop o) {

    VerifyArchiveOopClosure checkOop(_hr);

    assert(o != NULL, "Should not be here for NULL oops");

    o->oop_iterate(&checkOop);

  }

};

// Should be only used at CDS dump time

class VerifyReadyForArchivingRegionClosure : public HeapRegionClosure {

  bool _seen_free;

  bool _has_holes;

  bool _has_unexpected_holes;

  bool _has_humongous;

public:

  bool has_holes() {return _has_holes;}

  bool has_unexpected_holes() {return _has_unexpected_holes;}

  bool has_humongous() {return _has_humongous;}

  VerifyReadyForArchivingRegionClosure() : HeapRegionClosure() {

    _seen_free = false;

    _has_holes = false;

    _has_unexpected_holes = false;

    _has_humongous = false;

  }

  virtual bool do_heap_region(HeapRegion* hr) {

    const char* hole = "";

    if (hr->is_free()) {

      _seen_free = true;

    } else {

      if (_seen_free) {

        _has_holes = true;

        if (hr->is_humongous()) {

          hole = " hole";

        } else {

          _has_unexpected_holes = true;

          hole = " hole **** unexpected ****";

        }

      }

    }

    if (hr->is_humongous()) {

      _has_humongous = true;

    }

    log_info(gc, region, cds)("HeapRegion " INTPTR_FORMAT " %s%s", p2i(hr->bottom()), hr->get_type_str(), hole);

    return false;

  }

};

// We want all used regions to be moved to the bottom-end of the heap, so we have

// a contiguous range of free regions at the top end of the heap. This way, we can

// avoid fragmentation while allocating the archive regions.

//

// Before calling this, a full GC should have been executed with a single worker thread,

// so that no old regions would be moved to the middle of the heap.

void G1HeapVerifier::verify_ready_for_archiving() {

  VerifyReadyForArchivingRegionClosure cl;

  G1CollectedHeap::heap()->heap_region_iterate(&cl);

  if (cl.has_holes()) {

    log_warning(gc, verify)("All free regions should be at the top end of the heap, but"

                            " we found holes. This is probably caused by (unmovable) humongous"

                            " allocations, and may lead to fragmentation while"

                            " writing archive heap memory regions.");

  }

  if (cl.has_humongous()) {

    log_warning(gc, verify)("(Unmovable) humongous regions have been found and"

                            " may lead to fragmentation while"

                            " writing archive heap memory regions.");

  }

  assert(!cl.has_unexpected_holes(), "all holes should have been caused by humongous regions");

}

class VerifyArchivePointerRegionClosure: public HeapRegionClosure {

  virtual bool do_heap_region(HeapRegion* r) {

   if (r->is_archive()) {

      VerifyObjectInArchiveRegionClosure verify_oop_pointers(r, false);

      r->object_iterate(&verify_oop_pointers);

    }

    return false;

  }

};

void G1HeapVerifier::verify_archive_regions() {

  G1CollectedHeap*  g1h = G1CollectedHeap::heap();

  VerifyArchivePointerRegionClosure cl;

  g1h->heap_region_iterate(&cl);

}

class VerifyRegionClosure: public HeapRegionClosure {

private:

  bool             _par;

  VerifyOption     _vo;

  bool             _failures;

public:

  // _vo == UsePrevMarking -> use "prev" marking information,

  // _vo == UseNextMarking -> use "next" marking information,

  // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS

  VerifyRegionClosure(bool par, VerifyOption vo)

    : _par(par),

      _vo(vo),

      _failures(false) {}

  bool failures() {

    return _failures;

  }

  bool do_heap_region(HeapRegion* r) {

    guarantee(!r->has_index_in_opt_cset(), "Region %u still has opt collection set index %u", r->hrm_index(), r->index_in_opt_cset());

    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());

    // Humongous and old regions regions might be of any state, so can't check here.

    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());

    // Verify that the continues humongous regions' remembered set state matches the

    // one from the starts humongous region.

    if (r->is_continues_humongous()) {

      if (r->rem_set()->get_state_str() != r->humongous_start_region()->rem_set()->get_state_str()) {

         log_error(gc, verify)("Remset states differ: Region %u (%s) remset %s with starts region %u (%s) remset %s",

                               r->hrm_index(),

                               r->get_short_type_str(),

                               r->rem_set()->get_state_str(),

                               r->humongous_start_region()->hrm_index(),

                               r->humongous_start_region()->get_short_type_str(),

                               r->humongous_start_region()->rem_set()->get_state_str());

         _failures = true;

      }

    }

    // For archive regions, verify there are no heap pointers to

    // non-pinned regions. For all others, verify liveness info.

    if (r->is_closed_archive()) {

      VerifyObjectInArchiveRegionClosure verify_oop_pointers(r, false);

      r->object_iterate(&verify_oop_pointers);

      return true;

    } else if (r->is_open_archive()) {

      VerifyObjsInRegionClosure verify_open_archive_oop(r, _vo);

      r->object_iterate(&verify_open_archive_oop);

      return true;

    } else if (!r->is_continues_humongous()) {

      bool failures = false;

      r->verify(_vo, &failures);

      if (failures) {

        _failures = true;

      } else if (!r->is_starts_humongous()) {

        VerifyObjsInRegionClosure not_dead_yet_cl(r, _vo);

        r->object_iterate(&not_dead_yet_cl);

        if (_vo != VerifyOption_G1UseNextMarking) {

          if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {

            log_error(gc, verify)("[" PTR_FORMAT "," PTR_FORMAT "] max_live_bytes " SIZE_FORMAT " < calculated " SIZE_FORMAT,

                                  p2i(r->bottom()), p2i(r->end()), r->max_live_bytes(), not_dead_yet_cl.live_bytes());

            _failures = true;

          }

        } else {

          // When vo == UseNextMarking we cannot currently do a sanity

          // check on the live bytes as the calculation has not been

          // finalized yet.

        }

      }

    }

    return false; // stop the region iteration if we hit a failure

  }

};

// This is the task used for parallel verification of the heap regions

class G1ParVerifyTask: public AbstractGangTask {

private:

  G1CollectedHeap*  _g1h;

  VerifyOption      _vo;

  bool              _failures;

  HeapRegionClaimer _hrclaimer;

public:

  // _vo == UsePrevMarking -> use "prev" marking information,

  // _vo == UseNextMarking -> use "next" marking information,

  // _vo == UseFullMarking -> use "next" marking bitmap but no TAMS

  G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) :

      AbstractGangTask("Parallel verify task"),

      _g1h(g1h),

      _vo(vo),

      _failures(false),

      _hrclaimer(g1h->workers()->active_workers()) {}

  bool failures() {

    return _failures;

  }

  void work(uint worker_id) {

    HandleMark hm;

    VerifyRegionClosure blk(true, _vo);

    _g1h->heap_region_par_iterate_from_worker_offset(&blk, &_hrclaimer, worker_id);

    if (blk.failures()) {

      _failures = true;

    }

  }

};

void G1HeapVerifier::enable_verification_type(G1VerifyType type) {

  // First enable will clear _enabled_verification_types.

  if (_enabled_verification_types == G1VerifyAll) {

    _enabled_verification_types = type;

  } else {

    _enabled_verification_types |= type;

  }

}

bool G1HeapVerifier::should_verify(G1VerifyType type) {

  return (_enabled_verification_types & type) == type;

}

void G1HeapVerifier::verify(VerifyOption vo) {

  if (!SafepointSynchronize::is_at_safepoint()) {

    log_info(gc, verify)("Skipping verification. Not at safepoint.");

  }

  assert(Thread::current()->is_VM_thread(),

         "Expected to be executed serially by the VM thread at this point");

  log_debug(gc, verify)("Roots");

  VerifyRootsClosure rootsCl(vo);

  VerifyCLDClosure cldCl(_g1h, &rootsCl);

  // We apply the relevant closures to all the oops in the

  // system dictionary, class loader data graph, the string table

  // and the nmethods in the code cache.

  G1VerifyCodeRootOopClosure codeRootsCl(_g1h, &rootsCl, vo);

  G1VerifyCodeRootBlobClosure blobsCl(&codeRootsCl);

  {

    G1RootProcessor root_processor(_g1h, 1);

    root_processor.process_all_roots(&rootsCl, &cldCl, &blobsCl);

  }

  bool failures = rootsCl.failures() || codeRootsCl.failures();

  if (!_g1h->policy()->collector_state()->in_full_gc()) {

    // If we're verifying during a full GC then the region sets

    // will have been torn down at the start of the GC. Therefore

    // verifying the region sets will fail. So we only verify

    // the region sets when not in a full GC.

    log_debug(gc, verify)("HeapRegionSets");

    verify_region_sets();

  }