/*

 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.

 *

 * 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/shared/markBitMap.inline.hpp"

#include "gc/shenandoah/shenandoahHeap.hpp"

#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"

#include "gc/shenandoah/shenandoahMarkingContext.hpp"

ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions) :

  _top_bitmaps(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),

  _top_at_mark_starts_base(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),

  _top_at_mark_starts(_top_at_mark_starts_base -

                      ((uintx) heap_region.start() >> ShenandoahHeapRegion::region_size_bytes_shift())) {

  _mark_bit_map.initialize(heap_region, bitmap_region);

}

bool ShenandoahMarkingContext::is_bitmap_clear() const {

  ShenandoahHeap* heap = ShenandoahHeap::heap();

  size_t num_regions = heap->num_regions();

  for (size_t idx = 0; idx < num_regions; idx++) {

    ShenandoahHeapRegion* r = heap->get_region(idx);

    if (heap->is_bitmap_slice_committed(r) && !is_bitmap_clear_range(r->bottom(), r->end())) {

      return false;

    }

  }

  return true;

}

bool ShenandoahMarkingContext::is_bitmap_clear_range(HeapWord* start, HeapWord* end) const {

  return _mark_bit_map.get_next_marked_addr(start, end) == end;

}

void ShenandoahMarkingContext::initialize_top_at_mark_start(ShenandoahHeapRegion* r) {

  size_t idx = r->region_number();

  HeapWord *bottom = r->bottom();

  _top_at_mark_starts_base[idx] = bottom;

  _top_bitmaps[idx] = bottom;

}

void ShenandoahMarkingContext::capture_top_at_mark_start(ShenandoahHeapRegion *r) {

  size_t region_number = r->region_number();

  HeapWord* old_tams = _top_at_mark_starts_base[region_number];

  HeapWord* new_tams = r->top();

  assert(new_tams >= old_tams,

         "Region " SIZE_FORMAT", TAMS updates should be monotonic: " PTR_FORMAT " -> " PTR_FORMAT,

         region_number, p2i(old_tams), p2i(new_tams));

  assert(is_bitmap_clear_range(old_tams, new_tams),

         "Region " SIZE_FORMAT ", bitmap should be clear while adjusting TAMS: " PTR_FORMAT " -> " PTR_FORMAT,

         region_number, p2i(old_tams), p2i(new_tams));

  _top_at_mark_starts_base[region_number] = new_tams;

  _top_bitmaps[region_number] = new_tams;

}

void ShenandoahMarkingContext::reset_top_at_mark_start(ShenandoahHeapRegion* r) {

  _top_at_mark_starts_base[r->region_number()] = r->bottom();

}

HeapWord* ShenandoahMarkingContext::top_at_mark_start(ShenandoahHeapRegion* r) const {

  return _top_at_mark_starts_base[r->region_number()];

}

void ShenandoahMarkingContext::reset_top_bitmap(ShenandoahHeapRegion* r) {

  assert(is_bitmap_clear_range(r->bottom(), r->end()),

         "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number());

  _top_bitmaps[r->region_number()] = r->bottom();

}

void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) {

  HeapWord* bottom = r->bottom();

  HeapWord* top_bitmap = _top_bitmaps[r->region_number()];

  if (top_bitmap > bottom) {

    _mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap));

    _top_bitmaps[r->region_number()] = bottom;

  }

  assert(is_bitmap_clear_range(bottom, r->end()),

         "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number());

}

bool ShenandoahMarkingContext::is_complete() {

  return _is_complete.is_set();

}

void ShenandoahMarkingContext::mark_complete() {

  _is_complete.set();

}

void ShenandoahMarkingContext::mark_incomplete() {

  _is_complete.unset();

}