adding a new member to basic block class

Hi all,
i am writing a llvm pass and want to add an extra member to basic block class.
can i do it by changing class definition in basicblock.h??
do i need to recompile complete llvm after changing this class??

thanks alot,
Abhishek

Yes to both questions. But you should ask yourself 'why' and whether
there's another way that could be done.

-bw