exec-file-mismatch and native-gdbserver testing

[Philippe Waroquiers]

On Sat, 2020-05-16 at 21:10 +0100, Pedro Alves via Gdb wrote:
> 
> So I cooked up something.  Below's the resulting preliminary patch.
> 
> Seems to work nicely -- it fixes gdb.base/argv0-symlink.exp at least.
> I haven't run the testsuite yet.
I have looked at the patch and played a little bit in a native setup.
It worked as expected, the patch looks ok to me.

Note that buildid comparison means that the exec-file used by
GDB might not be the (same physical) exec-file of the process
being debugged.

For some specific scenarios, it might have an impact,
such as the user wanting to debug a copy of the file to avoid
'Text file busy', maybe some interaction with setuid/setgid, ... ?

Maybe good enough to mention this in the user manual and/or in the
'help set exec-file-
mismatch' ?
Or maybe GDB should give a message to the user for different files
but same buildid ?


> 
> There's (at least) one issue that I'll need to fix.  It's to
> get rid of the "transfers from remote targets can be slow" warning
> when we open the remote file to read the build id:

Note that before GDB 10 goes out with this new exec-file-mismatch feature,
we should sort out: https://sourceware.org/bugzilla/show_bug.cgi?id=25475
as possibly fixing this bug might imply to change the options of
   'set exec-file-mismatch'
(see last comment in the bug).

Thanks

Philippe