Re: [PATCH V4 1/3] gdb: support for eBPF

["Jose E. Marchesi" <jose.marchesi@oracle.com>]

Hi Simon.
    
    I have noted a few mostly stylistic comments.  I don't know much
    about eBPF, so I can't really comment on the behavior.

Thanks for the review.
    
    > +/* Frame unwinder.
    > +
    > +   XXX it is not clear how to unwind in eBPF, since the stack is not
    > +   guaranteed to be contiguous, and therefore no relative stack
    > +   addressing can be done in the callee in order to access the
    > +   caller's stack frame.  To explore with xBPF, which will relax this
    > +   restriction.  */
    > +
    > +/* Given THIS_FRAME, return its ID.  */
    > +
    > +static void
    > +bpf_frame_this_id (struct frame_info *this_frame,
    > +		   void **this_prologue_cache,
    > +		   struct frame_id *this_id)
    > +{
    > +}
    
    So if I understand correctly, at the moment there's no unwinding at all,
    there's always just one frame?  What ID does that frame have?  Would it
    still be good to assign something (constant) to *THIS_ID to make sure it's
    not random junk?

Would setting null_frame_id make sense there?