/*

 * Copyright (c) 2001, 2018, 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 "gc/g1/g1CardTable.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/shared/memset_with_concurrent_readers.hpp"

#include "logging/log.hpp"

#include "runtime/atomic.hpp"

bool G1CardTable::mark_card_deferred(size_t card_index) {

  jbyte val = _byte_map[card_index];

  // It's already processed

  if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {

    return false;

  }

  // Cached bit can be installed either on a clean card or on a claimed card.

  jbyte new_val = val;

  if (val == clean_card_val()) {

    new_val = (jbyte)deferred_card_val();

  } else {

    if (val & claimed_card_val()) {

      new_val = val | (jbyte)deferred_card_val();

    }

  }

  if (new_val != val) {

    Atomic::cmpxchg(new_val, &_byte_map[card_index], val);

  }

  return true;

}

void G1CardTable::g1_mark_as_young(const MemRegion& mr) {

  jbyte *const first = byte_for(mr.start());

  jbyte *const last = byte_after(mr.last());

  memset_with_concurrent_readers(first, g1_young_gen, last - first);

}

#ifndef PRODUCT

void G1CardTable::verify_g1_young_region(MemRegion mr) {

  verify_region(mr, g1_young_gen,  true);

}

#endif

void G1CardTableChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {

  // Default value for a clean card on the card table is -1. So we cannot take advantage of the zero_filled parameter.

  MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);

  _card_table->clear(mr);

}

void G1CardTable::initialize(G1RegionToSpaceMapper* mapper) {

  mapper->set_mapping_changed_listener(&_listener);

  _byte_map_size = mapper->reserved().byte_size();

  _guard_index = cards_required(_whole_heap.word_size()) - 1;

  _last_valid_index = _guard_index - 1;

  HeapWord* low_bound  = _whole_heap.start();

  HeapWord* high_bound = _whole_heap.end();

  _cur_covered_regions = 1;

  _covered[0] = _whole_heap;

  _byte_map = (jbyte*) mapper->reserved().start();

  _byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift);

  assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map");

  assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map");

  log_trace(gc, barrier)("G1CardTable::G1CardTable: ");

  log_trace(gc, barrier)("    &_byte_map[0]: " INTPTR_FORMAT "  &_byte_map[_last_valid_index]: " INTPTR_FORMAT,

                         p2i(&_byte_map[0]), p2i(&_byte_map[_last_valid_index]));

  log_trace(gc, barrier)("    _byte_map_base: " INTPTR_FORMAT,  p2i(_byte_map_base));

}

bool G1CardTable::is_in_young(oop obj) const {

  volatile jbyte* p = byte_for(obj);

  return *p == G1CardTable::g1_young_card_val();

}