/*

 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.

 *

 * 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 "gc/shenandoah/shenandoahAsserts.hpp"

#include "gc/shenandoah/shenandoahForwarding.inline.hpp"

#include "gc/shenandoah/shenandoahPhaseTimings.hpp"

#include "gc/shenandoah/shenandoahHeap.inline.hpp"

#include "gc/shenandoah/shenandoahRootProcessor.hpp"

#include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"

#include "gc/shenandoah/shenandoahUtils.hpp"

#include "gc/shenandoah/shenandoahVerifier.hpp"

#include "memory/allocation.hpp"

#include "memory/iterator.inline.hpp"

#include "memory/resourceArea.hpp"

#include "oops/compressedOops.inline.hpp"

// Avoid name collision on verify_oop (defined in macroAssembler_arm.hpp)

#ifdef verify_oop

#undef verify_oop

#endif

class ShenandoahVerifyOopClosure : public BasicOopIterateClosure {

private:

  const char* _phase;

  ShenandoahVerifier::VerifyOptions _options;

  ShenandoahVerifierStack* _stack;

  ShenandoahHeap* _heap;

  MarkBitMap* _map;

  ShenandoahLivenessData* _ld;

  void* _interior_loc;

  oop _loc;

public:

  ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,

                             const char* phase, ShenandoahVerifier::VerifyOptions options) :

    _phase(phase),

    _options(options),

    _stack(stack),

    _heap(ShenandoahHeap::heap()),

    _map(map),

    _ld(ld),

    _interior_loc(NULL),

    _loc(NULL) { }

private:

  void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {

    if (!test) {

      ShenandoahAsserts::print_failure(level, obj, _interior_loc, _loc, _phase, label, __FILE__, __LINE__);

    }

  }

  template <class T>

  void do_oop_work(T* p) {

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

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

      oop obj = CompressedOops::decode_not_null(o);

      // Single threaded verification can use faster non-atomic stack and bitmap

      // methods.

      //

      // For performance reasons, only fully verify non-marked field values.

      // We are here when the host object for *p is already marked.

      HeapWord* addr = (HeapWord*) obj;

      if (_map->par_mark(addr)) {

        verify_oop_at(p, obj);

        _stack->push(ShenandoahVerifierTask(obj));

      }

    }

  }

  void verify_oop(oop obj) {

    // Perform consistency checks with gradually decreasing safety level. This guarantees

    // that failure report would not try to touch something that was not yet verified to be

    // safe to process.

    check(ShenandoahAsserts::_safe_unknown, obj, _heap->is_in(obj),

              "oop must be in heap");

    check(ShenandoahAsserts::_safe_unknown, obj, check_obj_alignment(obj),

              "oop must be aligned");

    ShenandoahHeapRegion *obj_reg = _heap->heap_region_containing(obj);

    Klass* obj_klass = obj->klass_or_null();

    // Verify that obj is not in dead space:

    {

      // Do this before touching obj->size()

      check(ShenandoahAsserts::_safe_unknown, obj, obj_klass != NULL,

             "Object klass pointer should not be NULL");

      check(ShenandoahAsserts::_safe_unknown, obj, Metaspace::contains(obj_klass),

             "Object klass pointer must go to metaspace");

      HeapWord *obj_addr = (HeapWord *) obj;

      check(ShenandoahAsserts::_safe_unknown, obj, obj_addr < obj_reg->top(),

             "Object start should be within the region");

      if (!obj_reg->is_humongous()) {

        check(ShenandoahAsserts::_safe_unknown, obj, (obj_addr + obj->size()) <= obj_reg->top(),

               "Object end should be within the region");

      } else {

        size_t humongous_start = obj_reg->region_number();

        size_t humongous_end = humongous_start + (obj->size() >> ShenandoahHeapRegion::region_size_words_shift());

        for (size_t idx = humongous_start + 1; idx < humongous_end; idx++) {

          check(ShenandoahAsserts::_safe_unknown, obj, _heap->get_region(idx)->is_humongous_continuation(),

                 "Humongous object is in continuation that fits it");

        }

      }

      // ------------ obj is safe at this point --------------

      check(ShenandoahAsserts::_safe_oop, obj, obj_reg->is_active(),

            "Object should be in active region");

      switch (_options._verify_liveness) {

        case ShenandoahVerifier::_verify_liveness_disable:

          // skip

          break;

        case ShenandoahVerifier::_verify_liveness_complete:

          Atomic::add(obj->size() + ShenandoahForwarding::word_size(), &_ld[obj_reg->region_number()]);

          // fallthrough for fast failure for un-live regions:

        case ShenandoahVerifier::_verify_liveness_conservative:

          check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),

                   "Object must belong to region with live data");

          break;

        default:

          assert(false, "Unhandled liveness verification");

      }

    }

    oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);

    ShenandoahHeapRegion* fwd_reg = NULL;

    if (!oopDesc::equals_raw(obj, fwd)) {

      check(ShenandoahAsserts::_safe_oop, obj, _heap->is_in(fwd),

             "Forwardee must be in heap");

      check(ShenandoahAsserts::_safe_oop, obj, !CompressedOops::is_null(fwd),

             "Forwardee is set");

      check(ShenandoahAsserts::_safe_oop, obj, check_obj_alignment(fwd),

             "Forwardee must be aligned");

      // Do this before touching fwd->size()

      Klass* fwd_klass = fwd->klass_or_null();

      check(ShenandoahAsserts::_safe_oop, obj, fwd_klass != NULL,

             "Forwardee klass pointer should not be NULL");

      check(ShenandoahAsserts::_safe_oop, obj, Metaspace::contains(fwd_klass),

             "Forwardee klass pointer must go to metaspace");

      check(ShenandoahAsserts::_safe_oop, obj, obj_klass == fwd_klass,

             "Forwardee klass pointer must go to metaspace");

      fwd_reg = _heap->heap_region_containing(fwd);

      // Verify that forwardee is not in the dead space:

      check(ShenandoahAsserts::_safe_oop, obj, !fwd_reg->is_humongous(),

             "Should have no humongous forwardees");

      HeapWord *fwd_addr = (HeapWord *) fwd;

      check(ShenandoahAsserts::_safe_oop, obj, fwd_addr < fwd_reg->top(),

             "Forwardee start should be within the region");

      check(ShenandoahAsserts::_safe_oop, obj, (fwd_addr + fwd->size()) <= fwd_reg->top(),

             "Forwardee end should be within the region");

      oop fwd2 = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(fwd);

      check(ShenandoahAsserts::_safe_oop, obj, oopDesc::equals_raw(fwd, fwd2),

             "Double forwarding");

    } else {

      fwd_reg = obj_reg;

    }

    // ------------ obj and fwd are safe at this point --------------

    switch (_options._verify_marked) {

      case ShenandoahVerifier::_verify_marked_disable:

        // skip

        break;

      case ShenandoahVerifier::_verify_marked_incomplete:

        check(ShenandoahAsserts::_safe_all, obj, _heap->marking_context()->is_marked(obj),

               "Must be marked in incomplete bitmap");

        break;

      case ShenandoahVerifier::_verify_marked_complete:

        check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),

               "Must be marked in complete bitmap");

        break;

      default:

        assert(false, "Unhandled mark verification");

    }

    switch (_options._verify_forwarded) {

      case ShenandoahVerifier::_verify_forwarded_disable:

        // skip

        break;

      case ShenandoahVerifier::_verify_forwarded_none: {

        check(ShenandoahAsserts::_safe_all, obj, oopDesc::equals_raw(obj, fwd),

               "Should not be forwarded");

        break;

      }

      case ShenandoahVerifier::_verify_forwarded_allow: {

        if (!oopDesc::equals_raw(obj, fwd)) {

          check(ShenandoahAsserts::_safe_all, obj, obj_reg != fwd_reg,

                 "Forwardee should be in another region");

        }

        break;

      }

      default:

        assert(false, "Unhandled forwarding verification");

    }

    switch (_options._verify_cset) {

      case ShenandoahVerifier::_verify_cset_disable:

        // skip

        break;

      case ShenandoahVerifier::_verify_cset_none:

        check(ShenandoahAsserts::_safe_all, obj, !_heap->in_collection_set(obj),

               "Should not have references to collection set");

        break;

      case ShenandoahVerifier::_verify_cset_forwarded:

        if (_heap->in_collection_set(obj)) {

          check(ShenandoahAsserts::_safe_all, obj, !oopDesc::equals_raw(obj, fwd),

                 "Object in collection set, should have forwardee");

        }

        break;

      default:

        assert(false, "Unhandled cset verification");

    }

  }

public:

  /**

   * Verify object with known interior reference.

   * @param p interior reference where the object is referenced from; can be off-heap

   * @param obj verified object

   */

  template <class T>

  void verify_oop_at(T* p, oop obj) {

    _interior_loc = p;

    verify_oop(obj);

    _interior_loc = NULL;

  }

  /**

   * Verify object without known interior reference.

   * Useful when picking up the object at known offset in heap,

   * but without knowing what objects reference it.

   * @param obj verified object

   */

  void verify_oop_standalone(oop obj) {

    _interior_loc = NULL;

    verify_oop(obj);

    _interior_loc = NULL;

  }

  /**

   * Verify oop fields from this object.

   * @param obj host object for verified fields

   */

  void verify_oops_from(oop obj) {

    _loc = obj;

    obj->oop_iterate(this);

    _loc = NULL;

  }

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

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

};

class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {

private:

  size_t _used, _committed, _garbage;

public:

  ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};

  void heap_region_do(ShenandoahHeapRegion* r) {

    _used += r->used();

    _garbage += r->garbage();

    _committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;

  }

  size_t used() { return _used; }

  size_t committed() { return _committed; }

  size_t garbage() { return _garbage; }

};

class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {

private:

  ShenandoahHeap* _heap;

  const char* _phase;

  ShenandoahVerifier::VerifyRegions _regions;

public:

  ShenandoahVerifyHeapRegionClosure(const char* phase, ShenandoahVerifier::VerifyRegions regions) :

    _heap(ShenandoahHeap::heap()),

    _phase(phase),

    _regions(regions) {};

  void print_failure(ShenandoahHeapRegion* r, const char* label) {

    ResourceMark rm;

    ShenandoahMessageBuffer msg("Shenandoah verification failed; %s: %s\n\n", _phase, label);

    stringStream ss;

    r->print_on(&ss);

    msg.append("%s", ss.as_string());

    report_vm_error(__FILE__, __LINE__, msg.buffer());

  }

  void verify(ShenandoahHeapRegion* r, bool test, const char* msg) {

    if (!test) {

      print_failure(r, msg);

    }

  }

  void heap_region_do(ShenandoahHeapRegion* r) {

    switch (_regions) {

      case ShenandoahVerifier::_verify_regions_disable:

        break;

      case ShenandoahVerifier::_verify_regions_notrash:

        verify(r, !r->is_trash(),

               "Should not have trash regions");

        break;

      case ShenandoahVerifier::_verify_regions_nocset:

        verify(r, !r->is_cset(),

               "Should not have cset regions");

        break;

      case ShenandoahVerifier::_verify_regions_notrash_nocset:

        verify(r, !r->is_trash(),

               "Should not have trash regions");

        verify(r, !r->is_cset(),

               "Should not have cset regions");

        break;

      default:

        ShouldNotReachHere();

    }

    verify(r, r->capacity() == ShenandoahHeapRegion::region_size_bytes(),

           "Capacity should match region size");

    verify(r, r->bottom() <= r->top(),

           "Region top should not be less than bottom");

    verify(r, r->bottom() <= _heap->marking_context()->top_at_mark_start(r),

           "Region TAMS should not be less than bottom");

    verify(r, _heap->marking_context()->top_at_mark_start(r) <= r->top(),

           "Complete TAMS should not be larger than top");

    verify(r, r->get_live_data_bytes() <= r->capacity(),

           "Live data cannot be larger than capacity");

    verify(r, r->garbage() <= r->capacity(),

           "Garbage cannot be larger than capacity");

    verify(r, r->used() <= r->capacity(),

           "Used cannot be larger than capacity");

    verify(r, r->get_shared_allocs() <= r->capacity(),

           "Shared alloc count should not be larger than capacity");

    verify(r, r->get_tlab_allocs() <= r->capacity(),

           "TLAB alloc count should not be larger than capacity");

    verify(r, r->get_gclab_allocs() <= r->capacity(),

           "GCLAB alloc count should not be larger than capacity");

    verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),

           "Accurate accounting: shared + TLAB + GCLAB = used");

    verify(r, !r->is_empty() || !r->has_live(),

           "Empty regions should not have live data");

    verify(r, r->is_cset() == _heap->collection_set()->is_in(r),

           "Transitional: region flags and collection set agree");

    verify(r, r->is_empty() || r->seqnum_first_alloc() != 0,

           "Non-empty regions should have first seqnum set");

    verify(r, r->is_empty() || (r->seqnum_first_alloc_mutator() != 0 || r->seqnum_first_alloc_gc() != 0),

           "Non-empty regions should have first seqnum set to either GC or mutator");

    verify(r, r->is_empty() || r->seqnum_last_alloc() != 0,

           "Non-empty regions should have last seqnum set");

    verify(r, r->is_empty() || (r->seqnum_last_alloc_mutator() != 0 || r->seqnum_last_alloc_gc() != 0),

           "Non-empty regions should have last seqnum set to either GC or mutator");

    verify(r, r->seqnum_first_alloc() <= r->seqnum_last_alloc(),

           "First seqnum should not be greater than last timestamp");

    verify(r, r->seqnum_first_alloc_mutator() <= r->seqnum_last_alloc_mutator(),

           "First mutator seqnum should not be greater than last seqnum");

    verify(r, r->seqnum_first_alloc_gc() <= r->seqnum_last_alloc_gc(),

           "First GC seqnum should not be greater than last seqnum");

  }

};

class ShenandoahVerifierReachableTask : public AbstractGangTask {

private:

  const char* _label;

  ShenandoahVerifier::VerifyOptions _options;

  ShenandoahHeap* _heap;

  ShenandoahLivenessData* _ld;

  MarkBitMap* _bitmap;

  volatile size_t _processed;

public:

  ShenandoahVerifierReachableTask(MarkBitMap* bitmap,

                                  ShenandoahLivenessData* ld,

                                  const char* label,

                                  ShenandoahVerifier::VerifyOptions options) :

    AbstractGangTask("Shenandoah Parallel Verifier Reachable Task"),

    _label(label),

    _options(options),

    _heap(ShenandoahHeap::heap()),

    _ld(ld),

    _bitmap(bitmap),

    _processed(0) {};

  size_t processed() {

    return _processed;

  }

  virtual void work(uint worker_id) {

    ResourceMark rm;

    ShenandoahVerifierStack stack;

    // On level 2, we need to only check the roots once.

    // On level 3, we want to check the roots, and seed the local stack.

    // It is a lesser evil to accept multiple root scans at level 3, because

    // extended parallelism would buy us out.

    if (((ShenandoahVerifyLevel == 2) && (worker_id == 0))

        || (ShenandoahVerifyLevel >= 3)) {

        ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,

                                      ShenandoahMessageBuffer("%s, Roots", _label),

                                      _options);

    }

    size_t processed = 0;

    if (ShenandoahVerifyLevel >= 3) {

      ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,

                                    ShenandoahMessageBuffer("%s, Reachable", _label),

                                    _options);

      while (!stack.is_empty()) {

        processed++;

        ShenandoahVerifierTask task = stack.pop();

        cl.verify_oops_from(task.obj());

      }

    }

    Atomic::add(processed, &_processed);

  }

};

class ShenandoahVerifierMarkedRegionTask : public AbstractGangTask {

private:

  const char* _label;

  ShenandoahVerifier::VerifyOptions _options;

  ShenandoahHeap *_heap;

  MarkBitMap* _bitmap;

  ShenandoahLivenessData* _ld;

  volatile size_t _claimed;

  volatile size_t _processed;

public:

  ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,

                                     ShenandoahLivenessData* ld,

                                     const char* label,

                                     ShenandoahVerifier::VerifyOptions options) :

          AbstractGangTask("Shenandoah Parallel Verifier Marked Region"),

          _label(label),

          _options(options),

          _heap(ShenandoahHeap::heap()),

          _bitmap(bitmap),

          _ld(ld),

          _claimed(0),

          _processed(0) {};

  size_t processed() {

    return _processed;

  }

  virtual void work(uint worker_id) {

    ShenandoahVerifierStack stack;

    ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,

                                  ShenandoahMessageBuffer("%s, Marked", _label),

                                  _options);

    while (true) {

      size_t v = Atomic::add(1u, &_claimed) - 1;

      if (v < _heap->num_regions()) {

        ShenandoahHeapRegion* r = _heap->get_region(v);

        if (!r->is_humongous() && !r->is_trash()) {

          work_regular(r, stack, cl);

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

          work_humongous(r, stack, cl);

        }

      } else {

        break;

      }