luaO_chunkid
luaO_chunkid(ar->short_src, ar->source, LUA_IDSIZE);
luaO_chunkid(buff, getstr(src), LUA_IDSIZE);
luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
LUAI_FUNC void luaO_chunkid (char *out, const char *source, size_t len);