/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2018 SAP SE. 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 "utilities/debug.hpp"

#include "utilities/globalDefinitions.hpp"

#include "memory/metaspace/metachunk.hpp"

#include "memory/metaspace/occupancyMap.hpp"

#include "runtime/os.hpp"

namespace metaspace {

OccupancyMap::OccupancyMap(const MetaWord* reference_address, size_t word_size, size_t smallest_chunk_word_size) :

            _reference_address(reference_address), _word_size(word_size),

            _smallest_chunk_word_size(smallest_chunk_word_size)

{

  assert(reference_address != NULL, "invalid reference address");

  assert(is_aligned(reference_address, smallest_chunk_word_size),

      "Reference address not aligned to smallest chunk size.");

  assert(is_aligned(word_size, smallest_chunk_word_size),

      "Word_size shall be a multiple of the smallest chunk size.");

  // Calculate bitmap size: one bit per smallest_chunk_word_size'd area.

  size_t num_bits = word_size / smallest_chunk_word_size;

  _map_size = (num_bits + 7) / 8;

  assert(_map_size * 8 >= num_bits, "sanity");

  _map[0] = (uint8_t*) os::malloc(_map_size, mtInternal);

  _map[1] = (uint8_t*) os::malloc(_map_size, mtInternal);

  assert(_map[0] != NULL && _map[1] != NULL, "Occupancy Map: allocation failed.");

  memset(_map[1], 0, _map_size);

  memset(_map[0], 0, _map_size);

  // Sanity test: the first respectively last possible chunk start address in

  // the covered range shall map to the first and last bit in the bitmap.

  assert(get_bitpos_for_address(reference_address) == 0,

      "First chunk address in range must map to fist bit in bitmap.");

  assert(get_bitpos_for_address(reference_address + word_size - smallest_chunk_word_size) == num_bits - 1,

      "Last chunk address in range must map to last bit in bitmap.");

}

OccupancyMap::~OccupancyMap() {

  os::free(_map[0]);

  os::free(_map[1]);

}

#ifdef ASSERT

// Verify occupancy map for the address range [from, to).

// We need to tell it the address range, because the memory the

// occupancy map is covering may not be fully comitted yet.

void OccupancyMap::verify(MetaWord* from, MetaWord* to) {

  Metachunk* chunk = NULL;

  int nth_bit_for_chunk = 0;

  MetaWord* chunk_end = NULL;

  for (MetaWord* p = from; p < to; p += _smallest_chunk_word_size) {

    const unsigned pos = get_bitpos_for_address(p);

    // Check the chunk-starts-info:

    if (get_bit_at_position(pos, layer_chunk_start_map)) {

      // Chunk start marked in bitmap.

      chunk = (Metachunk*) p;

      if (chunk_end != NULL) {

        assert(chunk_end == p, "Unexpected chunk start found at %p (expected "

            "the next chunk to start at %p).", p, chunk_end);

      }

      assert(chunk->is_valid_sentinel(), "Invalid chunk at address %p.", p);

      if (chunk->get_chunk_type() != HumongousIndex) {

        guarantee(is_aligned(p, chunk->word_size()), "Chunk %p not aligned.", p);

      }

      chunk_end = p + chunk->word_size();

      nth_bit_for_chunk = 0;

      assert(chunk_end <= to, "Chunk end overlaps test address range.");

    } else {

      // No chunk start marked in bitmap.

      assert(chunk != NULL, "Chunk should start at start of address range.");

      assert(p < chunk_end, "Did not find expected chunk start at %p.", p);

      nth_bit_for_chunk ++;

    }

    // Check the in-use-info:

    const bool in_use_bit = get_bit_at_position(pos, layer_in_use_map);

    if (in_use_bit) {

      assert(!chunk->is_tagged_free(), "Chunk %p: marked in-use in map but is free (bit %u).",

          chunk, nth_bit_for_chunk);

    } else {

      assert(chunk->is_tagged_free(), "Chunk %p: marked free in map but is in use (bit %u).",

          chunk, nth_bit_for_chunk);

    }

  }

}

// Verify that a given chunk is correctly accounted for in the bitmap.

void OccupancyMap::verify_for_chunk(Metachunk* chunk) {

  assert(chunk_starts_at_address((MetaWord*) chunk),

      "No chunk start marked in map for chunk %p.", chunk);

  // For chunks larger than the minimal chunk size, no other chunk

  // must start in its area.

  if (chunk->word_size() > _smallest_chunk_word_size) {

    assert(!is_any_bit_set_in_region(((MetaWord*) chunk) + _smallest_chunk_word_size,

        chunk->word_size() - _smallest_chunk_word_size, layer_chunk_start_map),

        "No chunk must start within another chunk.");

  }

  if (!chunk->is_tagged_free()) {

    assert(is_region_in_use((MetaWord*)chunk, chunk->word_size()),

        "Chunk %p is in use but marked as free in map (%d %d).",

        chunk, chunk->get_chunk_type(), chunk->get_origin());

  } else {

    assert(!is_region_in_use((MetaWord*)chunk, chunk->word_size()),

        "Chunk %p is free but marked as in-use in map (%d %d).",

        chunk, chunk->get_chunk_type(), chunk->get_origin());

  }

}

#endif // ASSERT

} // namespace metaspace