About the “unknown argumnet” Error in developping with clang

Dear All,
I’m trying to add a command line option to Clang/Clang++.
What I have done is that I have modified the driver of Clang… But the compilation instance(perhaps named clang cc1) of Clang cannot identify the new option. And the console prints the ERROR:" unknown argumnet".
what’s more, when I have add the new command line argumnet to the “CC1Options.td”, the console prints the “ast infomation”(in my opinion) of the source File. I have no idea about the reason.
What operation should I do on the Clang now?
Thanks in advance.