Function atomic

3rd/lua-5.4.3/src/lgc.c:1516–1556

static lu_mem atomic (lua_State *L) {
  global_State *g = G(L);
  lu_mem work = 0;
  GCObject *origweak, *origall;
  GCObject *grayagain = g->grayagain;  /* save original list */
  g->grayagain = NULL;
  lua_assert(g->ephemeron == NULL && g->weak == NULL);
  lua_assert(!iswhite(g->mainthread));
  g->gcstate = GCSatomic;
  markobject(g, L);  /* mark running thread */
  /* registry and global metatables may be changed by API */
  markvalue(g, &g->l_registry);
  markmt(g);  /* mark global metatables */
  work += propagateall(g);  /* empties 'gray' list */
  /* remark occasional upvalues of (maybe) dead threads */
  work += remarkupvals(g);
  work += propagateall(g);  /* propagate changes */
  g->gray = grayagain;
  work += propagateall(g);  /* traverse 'grayagain' list */
  convergeephemerons(g);
  /* at this point, all strongly accessible objects are marked. */
  /* Clear values from weak tables, before checking finalizers */
  clearbyvalues(g, g->weak, NULL);
  clearbyvalues(g, g->allweak, NULL);
  origweak = g->weak; origall = g->allweak;
  separatetobefnz(g, 0);  /* separate objects to be finalized */
  work += markbeingfnz(g);  /* mark objects that will be finalized */
  work += propagateall(g);  /* remark, to propagate 'resurrection' */
  convergeephemerons(g);
  /* at this point, all resurrected objects are marked. */
  /* remove dead objects from weak tables */
  clearbykeys(g, g->ephemeron);  /* clear keys from all ephemeron tables */
  clearbykeys(g, g->allweak);  /* clear keys from all 'allweak' tables */
  /* clear values from resurrected weak tables */
  clearbyvalues(g, g->weak, origweak);
  clearbyvalues(g, g->allweak, origall);
  luaS_clearcache(g);
  g->currentwhite = cast_byte(otherwhite(g));  /* flip current white */
  lua_assert(g->gray == NULL);
  return work;  /* estimate of slots marked by 'atomic' */
}


static int sweepstep (lua_State *L, global_State *g,