543                    p2i(q), p2i(_sp->end())));
 544     index -= n_cards_back;
 545     offset = _array->offset_array(index);
 546   }
 547   assert(offset < N_words, "offset too large");
 548   index--;
 549   q -= offset;
 550   assert(q >= _sp->bottom(),
 551          err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT,
 552                  p2i(q), p2i(_sp->bottom())));
 553   assert(q < _sp->end(),
 554          err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT,
 555                  p2i(q), p2i(_sp->end())));
 556   HeapWord* n = q;
 557 
 558   while (n <= addr) {
 559     debug_only(HeapWord* last = q);   // for debugging
 560     q = n;
 561     n += _sp->block_size(n);
 562     assert(n > q,
 563            err_msg("Looping at n = " PTR_FORMAT " with last = " PTR_FORMAT","
 564                    " while querying blk_start(" PTR_FORMAT ")"
 565                    " on _sp = [" PTR_FORMAT "," PTR_FORMAT ")",
 566                    p2i(n), p2i(last), p2i(addr), p2i(_sp->bottom()), p2i(_sp->end())));
 567   }
 568   assert(q <= addr,
 569          err_msg("wrong order for current (" INTPTR_FORMAT ")" " <= arg (" INTPTR_FORMAT ")",
 570                  p2i(q), p2i(addr)));
 571   assert(addr <= n,
 572          err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")",
 573                  p2i(addr), p2i(n)));
 574   return q;
 575 }
 576 
 577 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful(
 578   const void* addr) const {
 579   assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
 580 
 581   assert(_bottom <= addr && addr < _end,
 582          "addr must be covered by this Array");
 583   // Must read this exactly once because it can be modified by parallel

 543                    p2i(q), p2i(_sp->end())));
 544     index -= n_cards_back;
 545     offset = _array->offset_array(index);
 546   }
 547   assert(offset < N_words, "offset too large");
 548   index--;
 549   q -= offset;
 550   assert(q >= _sp->bottom(),
 551          err_msg("q = " PTR_FORMAT " crossed below bottom = " PTR_FORMAT,
 552                  p2i(q), p2i(_sp->bottom())));
 553   assert(q < _sp->end(),
 554          err_msg("q = " PTR_FORMAT " crossed above end = " PTR_FORMAT,
 555                  p2i(q), p2i(_sp->end())));
 556   HeapWord* n = q;
 557 
 558   while (n <= addr) {
 559     debug_only(HeapWord* last = q);   // for debugging
 560     q = n;
 561     n += _sp->block_size(n);
 562     assert(n > q,
 563            err_msg("Looping at n = " PTR_FORMAT " with last = " PTR_FORMAT ","
 564                    " while querying blk_start(" PTR_FORMAT ")"
 565                    " on _sp = [" PTR_FORMAT "," PTR_FORMAT ")",
 566                    p2i(n), p2i(last), p2i(addr), p2i(_sp->bottom()), p2i(_sp->end())));
 567   }
 568   assert(q <= addr,
 569          err_msg("wrong order for current (" INTPTR_FORMAT ")" " <= arg (" INTPTR_FORMAT ")",
 570                  p2i(q), p2i(addr)));
 571   assert(addr <= n,
 572          err_msg("wrong order for arg (" INTPTR_FORMAT ") <= next (" INTPTR_FORMAT ")",
 573                  p2i(addr), p2i(n)));
 574   return q;
 575 }
 576 
 577 HeapWord* BlockOffsetArrayNonContigSpace::block_start_careful(
 578   const void* addr) const {
 579   assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
 580 
 581   assert(_bottom <= addr && addr < _end,
 582          "addr must be covered by this Array");
 583   // Must read this exactly once because it can be modified by parallel