Re: [PATCH] LLVMLinux: Remove warning about returning an uninitialized variable

[Behan Webster]

On 03/31/14 15:11, H. Peter Anvin wrote:
> On 03/31/2014 03:10 PM, Behan Webster wrote:
> > > > diff --git a/include/asm-generic/cmpxchg-local.h
> > > > b/include/asm-generic/cmpxchg-local.h
> > > > index d8d4c89..4c41bb8 100644
> > > > --- a/include/asm-generic/cmpxchg-local.h
> > > > +++ b/include/asm-generic/cmpxchg-local.h
> > > > @@ -41,6 +41,7 @@ static inline unsigned long
> > > > __cmpxchg_local_generic(volatile void *ptr,
> > > >            break;
> > > >        default:
> > > >            wrong_size_cmpxchg(ptr);
> > > > +        prev = 0;
> > > >        }
> > > >        raw_local_irq_restore(flags);
> > > >        return prev;
> > > Shouldn't this be a build time assert (__compiletime_error())?
> > I changed it to a __noreturn on wrong_size_cmpxchg thanks to James
> > Bottomley.
> >
> > Which would be better?
> __compiletime_error traps at compile time rather than link time, which
> is what you want.
The idea is to remove the compile time warning that the return code 
"prev" isn't initialized in the default case. Indicating that 
wrong_size_cmpxchg doesn't return fixes that false positive.

Behan

--
Behan Webster
behanw@xxxxxxxxxxxxxxxxxx

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