template <class T>
inline void G1RemSet::par_write_ref(HeapRegion* from, T* p, int tid) {

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      oop obj = oopDesc::load_decode_heap_oop(p);

  {- -------------------------------------------
  (1) (ASSERT)
      ---------------------------------------- -}

    #ifdef ASSERT
      // can't do because of races
      // assert(obj == NULL || obj->is_oop(), "expected an oop");

      // Do the safe subset of is_oop
      if (obj != NULL) {
    #ifdef CHECK_UNHANDLED_OOPS
        oopDesc* o = obj.obj();
    #else
        oopDesc* o = obj;
    #endif // CHECK_UNHANDLED_OOPS
        assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
        assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
      }
    #endif // ASSERT

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(from == NULL || from->is_in_reserved(p), "p is not in from");

  {- -------------------------------------------
  (1) HeapRegionRemSet::add_reference(OopOrNarrowOopStar from, int tid) を呼んで, 
      Remembered Set に情報を追加する.
      (ただし, 処理対象のオブジェクトに対応する HeapRegion が見つからなければ何もしない.
       また, 参照元が同一 HeapRegion 内にある場合も何もしない.)
      ---------------------------------------- -}

      HeapRegion* to = _g1->heap_region_containing(obj);
      if (to != NULL && from != to) {
    #if G1_REM_SET_LOGGING
        gclog_or_tty->print_cr("Adding " PTR_FORMAT " (" PTR_FORMAT ") to RS"
                               " for region [" PTR_FORMAT ", " PTR_FORMAT ")",
                               p, obj,
                               to->bottom(), to->end());
    #endif
        assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
        to->rem_set()->add_reference(p, tid);
      }
    }