Re: Thread-safe profiling

[Eric Christopher <echristo at apple dot com>]

On Mar 14, 2007, at 2:30 PM, Jan Hubicka wrote:

> > Hi,
> >
> > On the course of implementing this I hit some bugs in the  
> > expansion code
> > of these builtins and the i386 backend, which are also fixed by this
> > patch.
>
> This would be probably worth backporting separately to release
> branch(es).

I agree. I'd like to see it at least to 4.2, probably 4.1 for the  
various linux distros. :)

> The patch seems OK overall, but I don't see any handling of targets  
> that
> don't support synchronization primitives.  I think at least
> -fthread-safe-profiling option should give a sorry here and we  
> should be
> able to build libgcov so probably we need to ifdef the thread safe
> variants out somehow if building on such targets leads to
> sorry/ICE/whatever evil it should lead to.

Probably.

> Also I think the call profiling won't work, since it uses a global
> variable to figure out from where the function was called.  I think we
> probably need a thread local storage here, that should not be that bad
> (it is one variable per compilation unit).

With the emutls stuff it should be able to work even on targets without
TLS at least.

-eric