/*

 * Copyright (c) 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 "memory/archiveUtils.hpp"

#include "memory/metaspace.hpp"

#include "utilities/bitMap.inline.hpp"

#if INCLUDE_CDS

CHeapBitMap* ArchivePtrMarker::_ptrmap = NULL;

address* ArchivePtrMarker::_ptr_base;

address* ArchivePtrMarker::_ptr_end;

bool ArchivePtrMarker::_compacted;

void ArchivePtrMarker::initialize(CHeapBitMap* ptrmap, address* ptr_base, address* ptr_end) {

  assert(_ptrmap == NULL, "initialize only once");

  _ptr_base = ptr_base;

  _ptr_end = ptr_end;

  _compacted = false;

  _ptrmap = ptrmap;

  // Use this as initial guesstimate. We should need less space in the

  // archive, but if we're wrong the bitmap will be expanded automatically.

  size_t estimated_archive_size = MetaspaceGC::capacity_until_GC();

  // But set it smaller in debug builds so we always test the expansion code.

  // (Default archive is about 12MB).

  DEBUG_ONLY(estimated_archive_size = 6 * M);

  // We need one bit per pointer in the archive.

  _ptrmap->initialize(estimated_archive_size / sizeof(intptr_t));

}

void ArchivePtrMarker::mark_pointer(address* ptr_loc) {

  assert(_ptrmap != NULL, "not initialized");

  assert(!_compacted, "cannot mark anymore");

  if (_ptr_base <= ptr_loc && ptr_loc < _ptr_end) {

    address value = *ptr_loc;

    if (value != NULL) {

      assert(uintx(ptr_loc) % sizeof(intptr_t) == 0, "pointers must be stored in aligned addresses");

      size_t idx = ptr_loc - _ptr_base;

      if (_ptrmap->size() <= idx) {

        _ptrmap->resize((idx + 1) * 2);

      }

      assert(idx < _ptrmap->size(), "must be");

      _ptrmap->set_bit(idx);

      //tty->print_cr("Marking pointer [%p] -> %p @ " SIZE_FORMAT_W(9), ptr_loc, *ptr_loc, idx);

    }

  }

}

class ArchivePtrBitmapCleaner: public BitMapClosure {

  CHeapBitMap* _ptrmap;

  address* _ptr_base;

  address  _relocatable_base;

  address  _relocatable_end;

  size_t   _max_non_null_offset;

public:

  ArchivePtrBitmapCleaner(CHeapBitMap* ptrmap, address* ptr_base, address relocatable_base, address relocatable_end) :

    _ptrmap(ptrmap), _ptr_base(ptr_base),

    _relocatable_base(relocatable_base), _relocatable_end(relocatable_end), _max_non_null_offset(0) {}

  bool do_bit(size_t offset) {

    address* ptr_loc = _ptr_base + offset;

    address  ptr_value = *ptr_loc;

    if (ptr_value != NULL) {

      assert(_relocatable_base <= ptr_value && ptr_value < _relocatable_end, "do not point to arbitrary locations!");

      if (_max_non_null_offset < offset) {

        _max_non_null_offset = offset;

      }

    } else {

      _ptrmap->clear_bit(offset);

      DEBUG_ONLY(log_trace(cds, reloc)("Clearing pointer [" PTR_FORMAT  "] -> NULL @ " SIZE_FORMAT_W(9), p2i(ptr_loc), offset));

    }

    return true;

  }

  size_t max_non_null_offset() const { return _max_non_null_offset; }

};

void ArchivePtrMarker::compact(address relocatable_base, address relocatable_end) {

  assert(!_compacted, "cannot compact again");

  ArchivePtrBitmapCleaner cleaner(_ptrmap, _ptr_base, relocatable_base, relocatable_end);

  _ptrmap->iterate(&cleaner);

  compact(cleaner.max_non_null_offset());

}

void ArchivePtrMarker::compact(size_t max_non_null_offset) {

  assert(!_compacted, "cannot compact again");

  _ptrmap->resize(max_non_null_offset + 1);

  _compacted = true;

}

#endif // INCLUDE_CDS