Function atomic

third-party/lua-5.2.4/src/lgc.c:999–1037

static l_mem atomic (lua_State *L) {
  global_State *g = G(L);
  l_mem work = -cast(l_mem, g->GCmemtrav);  /* start counting work */
  GCObject *origweak, *origall;
  lua_assert(!iswhite(obj2gco(g->mainthread)));
  markobject(g, L);  /* mark running thread */
  /* registry and global metatables may be changed by API */
  markvalue(g, &g->l_registry);
  markmt(g);  /* mark basic metatables */
  /* remark occasional upvalues of (maybe) dead threads */
  remarkupvals(g);
  propagateall(g);  /* propagate changes */
  work += g->GCmemtrav;  /* stop counting (do not (re)count grays) */
  /* traverse objects caught by write barrier and by 'remarkupvals' */
  retraversegrays(g);
  work -= g->GCmemtrav;  /* restart counting */
  convergeephemerons(g);
  /* at this point, all strongly accessible objects are marked. */
  /* clear values from weak tables, before checking finalizers */
  clearvalues(g, g->weak, NULL);
  clearvalues(g, g->allweak, NULL);
  origweak = g->weak; origall = g->allweak;
  work += g->GCmemtrav;  /* stop counting (objects being finalized) */
  separatetobefnz(L, 0);  /* separate objects to be finalized */
  markbeingfnz(g);  /* mark objects that will be finalized */
  propagateall(g);  /* remark, to propagate `preserveness' */
  work -= g->GCmemtrav;  /* restart counting */
  convergeephemerons(g);
  /* at this point, all resurrected objects are marked. */
  /* remove dead objects from weak tables */
  clearkeys(g, g->ephemeron, NULL);  /* clear keys from all ephemeron tables */
  clearkeys(g, g->allweak, NULL);  /* clear keys from all allweak tables */
  /* clear values from resurrected weak tables */
  clearvalues(g, g->weak, origweak);
  clearvalues(g, g->allweak, origall);
  g->currentwhite = cast_byte(otherwhite(g));  /* flip current white */
  work += g->GCmemtrav;  /* complete counting */
  return work;  /* estimate of memory marked by 'atomic' */
}


static lu_mem singlestep (lua_State *L) {