gdb remote protocol breakpoints (Z0 command)

[Tom Tromey]

David> There are many things you might want to do at a breakpoint that lack
David> bytecode operators.  Just for starters,
[...]
David>     . there is no bytecode operator for calling arbitrary functions

I think this one is a pain to push into the remote, probably why it
wasn't done.

David>     . there is no 'continue' option (as in: ``after performing the
David>     requested commands, continue the current thread'')

This seems like a different kind of thing altogether.  Though I'm not
sure I understand the use case.  As a breakpoint condition it could be
done by always returning zero.

David> Has anyone else thought about these issuses and possibly sketched out
David> extensions to allow such capabilities?

We're looking at extending the "compile" command to add "compile cond",
where the compiled condition is injected into the inferior.  This is
still a little ways down the road for us.

This isn't entirely straightforward, though, and has other tradeoffs.
Also extending agent expressions would be reasonable.  I suppose some
feature negotiation here would be needed.

Tom