Modify Xtensa instruction relaxation

[daniel@xxxxxxxxxxx]

Hi everybody,

I would like to modify the relaxation behavior of Xtensa assembly. 
Furthermore, I only want to modify the last relaxation of a call8 
instruction.

So my question is: how do I know which is the last relaxation in a 
function?

I already know that one of the last relaxations is done in 
convert_frag_immed() in tc-xtensa.c. Can I somehow tell from the segment 
pointer or fragment pointer if I'm at the end of a function?

Thanks,
Daniel