Re: [Valgrind-users] helgrind and threadsafe-statics

[David F. <fa...@kd...>]

On Monday 09 June 2014 08:39:45 Patrick J. LoPresti wrote:
> Interesting! So on x86 and similar, they implement thread-safe Meyers
> singletons via the double-checked locking anti-pattern... Which is
> actually safe thanks to Intel's not-exactly-relaxed memory model.

Interesting indeed.
 
> > If g++ would be modified such that the "if (!guard.first_byte)" test can
> > be skipped at run-time then it would become possible for Helgrind and
> > DRD to recognize static initialization
> 
> If I understand you correctly (?), you plan to ask the g++ maintainers
> to tamper with their fast path to make life easier for Helgrind (?)

Yeah, I can't really see that happening, either.
Unless some of you have a really good relationship with the gcc maintainers 
:-)
 
> If so, I would suggest having a Plan B...
> 
> Would it make sense to re-think the happens-before/happens-after
> annotation macros for C++11?

Not sure what you mean exactly, so at the risk of asking the same question:

would it be possible for me to annotate a global static with some special 
macros that make helgrind understand what's happening?

I know, annotating all global statics one by one sounds horrible, but actually 
in my case they're already encapsulated in a macro, and I just need a way to 
remove all these false positives in order for helgrind to be usable.

-- 
David Faure, fa...@kd..., http://www.davidfaure.fr
Working on KDE Frameworks 5