Re: [PATCH,resubmit] Add static probes to runtime linker

[Roland McGrath <roland at hack dot frob dot com>]

> Since we are now defining a brand-new interface, it would be nice to
> make it possible for the debugger to be more efficient.

That sounds sensible to me.  Would you like to propose an alternate
set of probes to Gary's proposal?

> Lastly, could this interface be evolved? I don't know if system tap
> probes already have a mechanism for versioned interface. If they do,
> great. If not, the interface should probably include version number
> somewhere.

There is no particular versioning mechanism and I'm not aware of any
plan for the issue having been proposed.  So far the only use of sdt.h
probes in an "ABI-like" fashion is GDB's use of the setjmp/longjmp
probes.  For that, (IIRC) Tom Tromey and I just decided that it was
sufficiently unlikely that these probes would change in the future that
we could bake the expectation of their details into GDB and not really
have a versioning issue later on, so we could just put the general
question off.  Perhaps the new rtld probes will be sufficiently hairy
and less likely to be perfectly right the first time that we now need to
consider the general issue for real.  IMHO that should be done with the
participation of the systemtap and gdb mailing lists, rather than just
coming up with something ad hoc here.


Thanks,
Roland