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 * Copyright (c) 2017, 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.

 *

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#ifndef SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP

#define SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP

#include "gc/g1/g1RegionToSpaceMapper.hpp"

#include "memory/allocation.hpp"

#include "memory/memRegion.hpp"

#include "utilities/bitMap.hpp"

#include "utilities/globalDefinitions.hpp"

#include "utilities/macros.hpp"

class G1CMBitMap;

class G1CMTask;

class G1ConcurrentMark;

// Closure for iteration over bitmaps

class G1CMBitMapClosure VALUE_OBJ_CLASS_SPEC {

private:

  G1ConcurrentMark* const _cm;

  G1CMTask* const _task;

public:

  G1CMBitMapClosure(G1CMTask *task, G1ConcurrentMark* cm) : _task(task), _cm(cm) { }

  bool do_addr(HeapWord* const addr);

};

class G1CMBitMapMappingChangedListener : public G1MappingChangedListener {

 private:

  G1CMBitMap* _bm;

 public:

  G1CMBitMapMappingChangedListener() : _bm(NULL) {}

  void set_bitmap(G1CMBitMap* bm) { _bm = bm; }

  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);

};

// A generic mark bitmap for concurrent marking.  This is essentially a wrapper

// around the BitMap class that is based on HeapWords, with one bit per (1 << _shifter) HeapWords.

class G1CMBitMap VALUE_OBJ_CLASS_SPEC {

private:

  MemRegion _covered;    // The heap area covered by this bitmap.

  const int _shifter;    // Shift amount from heap index to bit index in the bitmap.

  BitMapView _bm;        // The actual bitmap.

  G1CMBitMapMappingChangedListener _listener;

  inline void check_mark(HeapWord* addr) NOT_DEBUG_RETURN;

  // Convert from bit offset to address.

  HeapWord* offset_to_addr(size_t offset) const {

    return _covered.start() + (offset << _shifter);

  }

  // Convert from address to bit offset.

  size_t addr_to_offset(const HeapWord* addr) const {

    return pointer_delta(addr, _covered.start()) >> _shifter;

  }

public:

  static size_t compute_size(size_t heap_size);

  // Returns the amount of bytes on the heap between two marks in the bitmap.

  static size_t mark_distance();

  // Returns how many bytes (or bits) of the heap a single byte (or bit) of the

  // mark bitmap corresponds to. This is the same as the mark distance above.

  static size_t heap_map_factor() {

    return mark_distance();

  }

  G1CMBitMap() : _covered(), _bm(), _shifter(LogMinObjAlignment), _listener() { _listener.set_bitmap(this); }

  // Initializes the underlying BitMap to cover the given area.

  void initialize(MemRegion heap, G1RegionToSpaceMapper* storage);

  // Read marks

  bool is_marked(HeapWord* addr) const {

    assert(_covered.contains(addr),

           "Address " PTR_FORMAT " is outside underlying space from " PTR_FORMAT " to " PTR_FORMAT,

           p2i(addr), p2i(_covered.start()), p2i(_covered.end()));

    return _bm.at(addr_to_offset(addr));

  }

  // Apply the closure to the addresses that correspond to marked bits in the bitmap.

  inline bool iterate(G1CMBitMapClosure* cl, MemRegion mr);

  // Return the address corresponding to the next marked bit at or after

  // "addr", and before "limit", if "limit" is non-NULL.  If there is no

  // such bit, returns "limit" if that is non-NULL, or else "endWord()".

  inline HeapWord* get_next_marked_addr(const HeapWord* addr,

                                        const HeapWord* limit) const;

  // The argument addr should be the start address of a valid object

  inline HeapWord* addr_after_obj(HeapWord* addr);

  void print_on_error(outputStream* st, const char* prefix) const;

  // Write marks.

  inline void mark(HeapWord* addr);

  inline void clear(HeapWord* addr);

  inline bool par_mark(HeapWord* addr);

  void clear_range(MemRegion mr);

};

#endif // SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP