[PATCHv3 7/7] gdb: some process_stratum_target should not be shared

[Tom Tromey]

>>>>> "Andrew" == Andrew Burgess via Gdb-patches <gdb-patches@sourceware.org> writes:

Andrew> For things like the Linux and FreeBSD native targets, as well as the
Andrew> remote target, this is absolutely true (or was made true).  But some
Andrew> targets were never updated to be shareable, for example, the
Andrew> core_target, which is used when reading core-files, stores some of its
Andrew> state in the program_space, but also, the core-file and the executable
Andrew> being debugged are closely related.

Andrew> As each add-inferior call creates an inferior with a new
Andrew> program_space, and doesn't automatically copy the executable, or the
Andrew> current core-file, I don't think it really makes sense to "share"
Andrew> core_target objects between inferiors.

Yeah, probably the core target just doesn't even make sense to share.

I guess if we did want to share it, we could move the state into the
core target.  Maybe this is worthwhile to do anyway?  I see a bunch of
uses of core_bfd (which is a #define reaching into the program space),
but some, e.g. in linux_read_core_file_mappings, seem like they could be
replaced with a parameter.

Andrew> I think this behaviour might be confusing, so I'd like to have GDB not
Andrew> initially share the core connection.  Instead, when the user tries to
Andrew> add the new inferior a warning is given, and the new inferior is
Andrew> created without a connection, like this:

This makes sense to me.

Andrew> +  /* The core_target only works for the inferior in which it was initially
Andrew> +     opened, and can't be copied to some other inferior's target_stack.  */
Andrew> +  bool is_shareable () override
Andrew> +  { return false; }

However, why only mark the core target this way?

I think there are a lot of other targets that can't be
shared... remote-sim, all the trace targets, even I think windows-nat,
since it isn't multi-inferior-capable yet.

So maybe the default implementation should be 'return false' and then
specific known-good targets should override it?

Tom