Re: per thread breakpoints

[Quality Quorum <qqi at world dot std dot com>]

On Wed, 1 Nov 2000, Andrew Cagney wrote:

> Quality Quorum wrote:
> > 
> > Hi,
> > 
> > It seems to me that gdb core does NOT seriously support per thread breaks:
> > 
> > 1. target_insert_breakpoint() is unaware about thread associated with
> >    a breakpoint.
> 
> Yes.  The original thread model was developed on systems that didn't
> have kernel level threads (it wasn't SMP either :-).  Various
> assumptions were made such as it wasn't actually possible to set a
> breakpoint on a specific thread.  Instead all breakpoints were set
> globally.
> 
> > 2. insert_breakpoints() does not do any dances with inferior pids before
> >    and after calls to target_insert_breakpoint().
> > 
> > I would suppose it should be fixed ASAP (e.g. by adding pid argument to
> > to the target_insert_breakpoint): it is a huge resource hog in
> > case of remote debugging and it seems like linux threads would also
> > greatly benefit from this improvement.
> 
> I don't think it is that easy.  I recently looked through the thread
> code to see what would need changing.  At present GDB makes all sorts of
> assumptions about breakpoints and their sideeffects.  From memory,
> things like the way GDB iterates over breakpoints and resolves
> duplicates would also need to be changed.
> 
> Rather than a simplistic tweek, I think there needs to be a clear robust
> thread model that GDB can map onto all real thread implementations.

Again, it seems to me as an urgent issue.

> 
> 	Andrew
> 

Thanks,

Aleksey