Re: [PATCH v2 00/24] Multi-target support

Pedro Alves
2019-10-29T19:56:54Z

On 10/20/19 12:41 PM, Philippe Waroquiers wrote:
> I played a little bit with the patch and valgrind
> (I had to apply the patch with git am --3way, otherwise it failed to apply).

Guess you missed that this was in the users/palves/multi-target-v2 branch. :-/

> No problem encountered when playing with the result.
> I also re-read the documentation (as I forgot about how this was all
> working), and it was all pretty clear.

That's great to hear.

>
> 3 notes:
> * It might be interesting to one day add
> something like 'inferior apply all/list of inferiors SOMMECOMMAND'

Agreed.

> * when having 2 inferiors connected to 2 different valgrind gdbservers,
> I could continue both inferiors by using 'continue&',
> but I had to (artificially) issue 'interrupt' in the second inferior
> to have GDB accepting 'continue&'. So, this might be the indication
> of a status 'running' which should be maintained per inferior,
> while it might now be maintained globally.

I've tried to debug this a little, but I'd like to punt for now. The error
I'm seeing first comes from a breakpoint re-set, where gdb tries to
read memory from the valgrind that is running. Breakpoint re-sets currently
are too dumb and re-set all locations, instead of only adding/removing
the locations necessary. And then that is running into the fact that
the remote protocol in the old all-stop mode (which is what valgrind supports)
is synchronous, gdb can't talk to the remote target until the target
reports a stop.

These sorts of issues is why I required that the remote backends
support non-stop mode for this initial pass. I'd rather not have to fix
all these issues before landing the initial multi-target support, even
if we know there are issues we need to fix to make it cope better with
all-stop-only targets.

> * I was (again?) confused by add-inferior silently ignoring abbreviations
> (or more generally anything starting with - unless matching exactly
> an option).
> Waiting for option framework to be extended, the add-inferior command
> could use the below that accepts abbreviations and does not ignore
> wrong options.

Yes, that is fine with me.

Thanks,
Pedro Alves