Function luaG_traceexec

third-party/lua-5.3.5/src/ldebug.c:666–698

void luaG_traceexec (lua_State *L) {
  CallInfo *ci = L->ci;
  lu_byte mask = L->hookmask;
  int counthook = (--L->hookcount == 0 && (mask & LUA_MASKCOUNT));
  if (counthook)
    resethookcount(L);  /* reset count */
  else if (!(mask & LUA_MASKLINE))
    return;  /* no line hook and count != 0; nothing to be done */
  if (ci->callstatus & CIST_HOOKYIELD) {  /* called hook last time? */
    ci->callstatus &= ~CIST_HOOKYIELD;  /* erase mark */
    return;  /* do not call hook again (VM yielded, so it did not move) */
  }
  if (counthook)
    luaD_hook(L, LUA_HOOKCOUNT, -1);  /* call count hook */
  if (mask & LUA_MASKLINE) {
    Proto *p = ci_func(ci)->p;
    int npc = pcRel(ci->u.l.savedpc, p);
    int newline = getfuncline(p, npc);
    if (npc == 0 ||  /* call linehook when enter a new function, */
        ci->u.l.savedpc <= L->oldpc ||  /* when jump back (loop), or when */
        newline != getfuncline(p, pcRel(L->oldpc, p)))  /* enter a new line */
      luaD_hook(L, LUA_HOOKLINE, newline);  /* call line hook */
  }
  L->oldpc = ci->u.l.savedpc;
  if (L->status == LUA_YIELD) {  /* did hook yield? */
    if (counthook)
      L->hookcount = 1;  /* undo decrement to zero */
    ci->u.l.savedpc--;  /* undo increment (resume will increment it again) */
    ci->callstatus |= CIST_HOOKYIELD;  /* mark that it yielded */
    ci->func = L->top - 1;  /* protect stack below results */
    luaD_throw(L, LUA_YIELD);
  }
}