Stepping through signal trampolines

[Andrew Cagney]

> So there still seem to be some quirks with stepping through signal
> trampolines.  But before we decide what's the bug, I think we should
> ask ourselves what the desired behaviour is.  In my view:
> 
> * "finish" from within a signal handler should make us return to the
>   signal trampoline.
> 
> * "finish" from within a signal trampoline should make us return to
>   the point where the signal interruption occured.
> 
> * "stepi" from within a signal handler should step through the signal
>   handler and back into the signal trampoline.
> 
> * "stepi" from within a signal trampoline should step through the
>   signal trampoline until the sigreturn system call.

* nexti in a sigtramp is like stepi

What about disassemble?  Disassemble the entire signal trampoline or the 
current instruction?

(you now know where my testcases are going :-)

Andrew