src/hotspot/share/gc/z/zBitMap.inline.hpp

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#ifndef SHARE_GC_Z_ZBITMAP_INLINE_HPP
#define SHARE_GC_Z_ZBITMAP_INLINE_HPP

#include "gc/z/zBitMap.hpp"

#include "runtime/atomic.hpp"
#include "utilities/bitMap.inline.hpp"
#include "utilities/debug.hpp"

inline ZMovableBitMap::ZMovableBitMap()
  : CHeapBitMap(mtGC) {}

inline ZMovableBitMap::ZMovableBitMap(ZMovableBitMap&& bitmap)
  : CHeapBitMap(mtGC) {
  update(bitmap.map(), bitmap.size());
  bitmap.update(nullptr, 0);
}

inline ZBitMap::ZBitMap(idx_t size_in_bits)
  : CHeapBitMap(size_in_bits, mtGC, false /* clear */) {}

inline ZBitMap::ZBitMap(const ZBitMap& other)
  : CHeapBitMap(other.size(), mtGC, false /* clear */) {
  memcpy(map(), other.map(), size_in_bytes());
}

inline BitMap::bm_word_t ZBitMap::bit_mask_pair(idx_t bit) {
  assert(bit_in_word(bit) < BitsPerWord - 1, "Invalid bit index");
  return (bm_word_t)3 << bit_in_word(bit);
}

inline bool ZBitMap::par_set_bit_pair_finalizable(idx_t bit, bool& inc_live) {
  inc_live = par_set_bit(bit);
  return inc_live;
}

inline bool ZBitMap::par_set_bit_pair_strong(idx_t bit, bool& inc_live) {
  verify_index(bit);
  volatile bm_word_t* const addr = word_addr(bit);
  const bm_word_t pair_mask = bit_mask_pair(bit);
  bm_word_t old_val = *addr;

  do {
    const bm_word_t new_val = old_val | pair_mask;
    if (new_val == old_val) {
      // Someone else beat us to it
      inc_live = false;
      return false;
    }
    const bm_word_t cur_val = Atomic::cmpxchg(addr, old_val, new_val);
    if (cur_val == old_val) {
      // Success
      const bm_word_t marked_mask = bit_mask(bit);
      inc_live = !(old_val & marked_mask);
      return true;
    }

    // The value changed, retry
    old_val = cur_val;
  } while (true);
}

inline bool ZBitMap::par_set_bit_pair(idx_t bit, bool finalizable, bool& inc_live) {
  if (finalizable) {
    return par_set_bit_pair_finalizable(bit, inc_live);
  } else {
    return par_set_bit_pair_strong(bit, inc_live);
  }
}

inline ZBitMap::ReverseIterator::ReverseIterator(BitMap* bitmap)
  : ZBitMap::ReverseIterator(bitmap, 0, bitmap->size()) {}

inline ZBitMap::ReverseIterator::ReverseIterator(BitMap* bitmap, BitMap::idx_t beg, BitMap::idx_t end)
  : _bitmap(bitmap),
    _beg(beg),
    _end(end) {}

inline void ZBitMap::ReverseIterator::reset(BitMap::idx_t beg, BitMap::idx_t end) {
  assert(beg < _bitmap->size(), "beg index out of bounds");
  assert(end >= beg && end <= _bitmap->size(), "end index out of bounds");
  _beg = beg;
  _end = end;
}

inline void ZBitMap::ReverseIterator::reset(BitMap::idx_t end) {
  assert(end >= _beg && end <= _bitmap->size(), "end index out of bounds");
  _end = end;
}

inline bool ZBitMap::ReverseIterator::next(BitMap::idx_t *index) {
  BitMap::ReverseIterator iter(*_bitmap, _beg, _end);
  if (iter.is_empty()) {
    return false;
  }

  *index = _end = iter.index();
  return true;
}

#endif // SHARE_GC_Z_ZBITMAP_INLINE_HPP