Re: [3/7] Adjust the bsd-uthread target

Pedro Alves
2008-08-11T13:33:30Z

On Saturday 09 August 2008 02:31:30, Daniel Jacobowitz wrote:
> On Fri, Aug 08, 2008 at 11:41:23PM +0100, Pedro Alves wrote:
> > The "exited" state is what you get *after* you delete_thread the current
> > thread (inferior_ptid). We don't delete the thread from the thread list
> > in that case, but instead tag it as "exited". It means the thread list
> > is still holding reference to a thread that has already exited.
> > If you're seeing an event with a ptid equal to an "exited" thread,
> > this is the OS reusing the ptid, but, it's a new thread, which
> > should get a new gdb thread id, so things like thread
> > specific breakpoints don't think this was the same thread, both the
> > CLI user or MI see a "new thread event", etc. add_thread handles
> > that case internally. This means it is now safe to delete_thread
> > (inferior_ptid), regarding context-switching, and infrun state. It
> > wasn't a couple of weeks ago.

> How many of the call sites for in_thread_list want to see exited
> threads? Maybe there should be another predicate (I'd suggest
> thread_alive except target_thread_alive would confuse things...)

I actually started out using a new predicate, but then got rid
of it, as it looked more confusing to me.

There are a few calls than want to see all threads. context_switch (while
it still exists :-) ) and handle_inferior_event want to. The
breakpoints.c and infcmd.c calls don't care currently.

Can I ask you to not do that now, please? I can come back to it
as an follow-up cleanup. I've got several patches that touch
contexts where this form was used, and it would be a lot of work
to rebase and retest them all for not much gain. A single patch
to cleanup and introduce a new predicate can be made in one sweep.

--
Pedro Alves