/*
 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates.
 *
 * 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.
 *
 */

#ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHVERIFIER_HPP
#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHVERIFIER_HPP

#include "memory/allocation.hpp"
#include "utilities/stack.hpp"
#include "gc/shared/markBitMap.hpp"

class Thread;
class ShenandoahHeapRegionSet;
class ShenandoahHeap;
class ShenandoahVerifyOopClosure;

#ifdef _WINDOWS
#pragma warning( disable : 4522 )
#endif

class ShenandoahVerifierTask {
public:
  ShenandoahVerifierTask(oop o = NULL, int idx = 0): _obj(o) { }
  ShenandoahVerifierTask(oop o, size_t idx): _obj(o) { }
  ShenandoahVerifierTask(const ShenandoahVerifierTask& t): _obj(t._obj) { }

  ShenandoahVerifierTask& operator =(const ShenandoahVerifierTask& t) {
    _obj = t._obj;
    return *this;
  }
  volatile ShenandoahVerifierTask&
  operator =(const volatile ShenandoahVerifierTask& t) volatile {
    (void)const_cast<oop&>(_obj = t._obj);
    return *this;
  }

  inline oop obj()  const { return _obj; }

  DEBUG_ONLY(bool is_valid() const); // Tasks to be pushed/popped must be valid.

private:
  oop _obj;
};

typedef FormatBuffer<8192> ShenandoahMessageBuffer;
typedef Stack<ShenandoahVerifierTask, mtGC> ShenandoahVerifierStack;
typedef volatile juint ShenandoahLivenessData;

class ShenandoahVerifier : public CHeapObj<mtGC> {
private:
  ShenandoahHeap* _heap;
  MarkBitMap* _verification_bit_map;
public:
  typedef enum {
    // Disable matrix verification completely
    _verify_matrix_disable,

    // Conservative matrix verification: all connected objects should have matrix
    // connections. The verification is conservative, because it allows matrix
    // connection that do not have actual heap connections.
    _verify_matrix_conservative,

    // Precise matrix verification: all connected objects should have matrix connections,
    // *and* every matrix connection should have at least a pair a connected objects.
    // TODO: implement this, if needed
    _verify_matrix_precise,
  } VerifyMatrix;

  typedef enum {
    // Disable marked objects verification.
    _verify_marked_disable,

    // Objects should be marked
    _verify_marked,

  } VerifyMarked;

  typedef enum {
    // Disable forwarded objects verification.
    _verify_forwarded_disable,

    // Objects should not have forwardees.
    _verify_forwarded_none,

    // Objects may have forwardees.
    _verify_forwarded_allow,
  } VerifyForwarded;

  typedef enum {
    // Disable collection set verification.
    _verify_cset_disable,

    // Should have no references to cset.
    _verify_cset_none,

    // May have references to cset, all should be forwarded.
    // Note: Allowing non-forwarded references to cset is equivalent
    // to _verify_cset_disable.
    _verify_cset_forwarded,
  } VerifyCollectionSet;

  typedef enum {
    // Disable liveness verification
    _verify_liveness_disable,

    // All objects should belong to live regions
    _verify_liveness_conservative,

    // All objects should belong to live regions,
    // and liveness data should be accurate
    _verify_liveness_complete,
  } VerifyLiveness;

  typedef enum {
    // Disable region verification
    _verify_regions_disable,

    // No trash regions allowed
    _verify_regions_notrash,

    // No collection set regions allowed
    _verify_regions_nocset,

    // No trash and no cset regions allowed
    _verify_regions_notrash_nocset,
  } VerifyRegions;

  struct VerifyOptions {
    VerifyForwarded     _verify_forwarded;
    VerifyMarked        _verify_marked;
    VerifyMatrix        _verify_matrix;
    VerifyCollectionSet _verify_cset;
    VerifyLiveness      _verify_liveness;
    VerifyRegions       _verify_regions;

    VerifyOptions(VerifyForwarded verify_forwarded,
                  VerifyMarked verify_marked,
                  VerifyMatrix verify_matrix,
                  VerifyCollectionSet verify_collection_set,
                  VerifyLiveness verify_liveness,
                  VerifyRegions verify_regions) :
            _verify_forwarded(verify_forwarded), _verify_marked(verify_marked),
            _verify_matrix(verify_matrix), _verify_cset(verify_collection_set),
            _verify_liveness(verify_liveness), _verify_regions(verify_regions) {}
  };

private:
  void verify_at_safepoint(const char *label,
                           VerifyForwarded forwarded,
                           VerifyMarked marked,
                           VerifyMatrix matrix,
                           VerifyCollectionSet cset,
                           VerifyLiveness liveness,
                           VerifyRegions regions);

public:
  ShenandoahVerifier(ShenandoahHeap* heap, MarkBitMap* verification_bitmap) :
          _heap(heap), _verification_bit_map(verification_bitmap) {};

  void verify_before_concmark();
  void verify_after_concmark();
  void verify_before_evacuation();
  void verify_after_evacuation();
  void verify_before_updaterefs();
  void verify_after_updaterefs();
  void verify_before_fullgc();
  void verify_after_fullgc();
  void verify_before_partial();
  void verify_after_partial();
  void verify_generic(VerifyOption option);

  static void verify_oop(oop obj);
  static void verify_oop_fwdptr(oop obj, oop new_fwd);
};

#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHVERIFIER_HPP