Re: [PATCH 0/2] Fix x86 debug registers on FreeBSD with threads

[Pedro Alves <palves at redhat dot com>]

On 06/28/2016 11:55 PM, John Baldwin wrote:
> The pan-BSD x86 debug register support code was only setting the
> debug registers on the current LWP identified by inferior_ptid.
> This fixes the code to set the debug registers on all of the LWPs
> belonging to the current inferior on each change.

Looks good to me.

Spotted a missing space in:

  ALL_NON_EXITED_THREADS(thread)

> 
> One question I have is that the amd64 x86 debug register code was 
> invoking x86_cleanup_dregs in the mourn_inferior target op, but
> the x86 linux native code calls this in the post_startup_inferior
> target op instead.  Any ideas as to why they are different?

Not sure.  Probably history, or maybe to be sure to paper over
potential problems from the "inferior exit/dies/detached" end missing
clearing the reg state.  OTOH, I think target_post_startup_inferior
isn't called for attach.  
Note that mourn_inferior isn't called in some cases.  Some targets call
it from within their to_detach and to_kill target methods, but that's
not guaranteed.  I think that linux-nat.c doesn't call it from its
to_detach, but OTOH, when you get there, watchpoints had better have
been removed from the target already.  But maybe there's a problem
as follow-fork time, not sure.  Note that the linux native code
also calls x86_forget_process directly through linux_nat_forget_process.

> 
> John Baldwin (2):
>   Consolidate x86 debug register code for BSD native targets.
>   Set debug registers on all threads belonging to the current inferior.

Thanks,
Pedro Alves