src/hotspot/share/gc/g1/g1BlockOffsetTable.inline.hpp

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#ifndef SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
#define SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP

#include "gc/g1/g1BlockOffsetTable.hpp"

#include "gc/g1/heapRegion.hpp"
#include "gc/shared/memset_with_concurrent_readers.hpp"
#include "runtime/atomic.hpp"
#include "oops/oop.inline.hpp"

inline HeapWord* G1BlockOffsetTablePart::block_start_reaching_into_card(const void* addr) const {
  assert(addr >= _hr->bottom() && addr < _hr->top(), "invalid address");

#ifdef ASSERT
  if (!_hr->is_continues_humongous()) {
    // For non-ContinuesHumongous regions, the first obj always starts from bottom.
    u_char offset = _bot->offset_array(_bot->index_for(_hr->bottom()));
    assert(offset == 0, "Found offset %u instead of 0 for region %u %s",
           offset, _hr->hrm_index(), _hr->get_short_type_str());
  }
#endif

  size_t index = _bot->index_for(addr);

  uint offset = _bot->offset_array(index);
  while (offset >= BOTConstants::card_size_in_words()) {
    // The excess of the offset from N_words indicates a power of Base
    // to go back by.
    size_t n_cards_back = BOTConstants::entry_to_cards_back(offset);
    index -= n_cards_back;
    offset = _bot->offset_array(index);
  }
  assert(offset < BOTConstants::card_size_in_words(), "offset too large");

  HeapWord* q = _bot->address_for_index(index);
  return q - offset;
}

u_char G1BlockOffsetTable::offset_array(size_t index) const {
  check_index(index, "index out of range");
  return Atomic::load(&_offset_array[index]);
}

void G1BlockOffsetTable::set_offset_array_raw(size_t index, u_char offset) {
  Atomic::store(&_offset_array[index], offset);
}

void G1BlockOffsetTable::set_offset_array(size_t index, u_char offset) {
  check_index(index, "index out of range");
  set_offset_array_raw(index, offset);
}

void G1BlockOffsetTable::set_offset_array(size_t index, HeapWord* high, HeapWord* low) {
  check_index(index, "index out of range");
  assert(high >= low, "addresses out of order");
  size_t offset = pointer_delta(high, low);
  check_offset(offset, "offset too large");
  set_offset_array(index, (u_char)offset);
}

void G1BlockOffsetTable::set_offset_array(size_t left, size_t right, u_char offset) {
  check_index(right, "right index out of range");
  assert(left <= right, "indexes out of order");
  size_t num_cards = right - left + 1;
  memset_with_concurrent_readers
    (const_cast<u_char*> (&_offset_array[left]), offset, num_cards);
}

// Variant of index_for that does not check the index for validity.
inline size_t G1BlockOffsetTable::index_for_raw(const void* p) const {
  return pointer_delta((char*)p, _reserved.start(), sizeof(char)) >> BOTConstants::log_card_size();
}

inline size_t G1BlockOffsetTable::index_for(const void* p) const {
  char* pc = (char*)p;
  assert(pc >= (char*)_reserved.start() &&
         pc <  (char*)_reserved.end(),
         "p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
         p2i(p), p2i(_reserved.start()), p2i(_reserved.end()));
  size_t result = index_for_raw(p);
  check_index(result, "bad index from address");
  return result;
}

inline HeapWord* G1BlockOffsetTable::address_for_index(size_t index) const {
  check_index(index, "index out of range");
  HeapWord* result = address_for_index_raw(index);
  assert(result >= _reserved.start() && result < _reserved.end(),
         "bad address from index result " PTR_FORMAT
         " _reserved.start() " PTR_FORMAT " _reserved.end() " PTR_FORMAT,
         p2i(result), p2i(_reserved.start()), p2i(_reserved.end()));
  return result;
}

#endif // SHARE_GC_G1_G1BLOCKOFFSETTABLE_INLINE_HPP