On 5/22/07, Satyam Sharma <[email protected]> wrote:
On 5/22/07, Robert P. J. Day <[email protected]> wrote:
> On Tue, 22 May 2007, John Anthony Kazos Jr. wrote:
>
> > > given that:
> > >
> > > $ grep -r "define.*NORET_TYPE" *
> > > include/linux/ext4_fs.h:# define NORET_TYPE /**/
> > > include/linux/linkage.h:#define NORET_TYPE /**/
> > > include/linux/ext3_fs.h:# define NORET_TYPE /**/
> > > $
> > >
> > > is there any obvious value to the 30 or so uses of that macro
> > > sprinkled throughout the tree?
> >
> > Since it evaluates to absolutely empty code during pre-processing,
> > there is no obvious value. The question is whether there is some odd
> > hackish non-obvious value, I'd expect. (I'd also expect that to be
> > another "no".)
> >
> > If something that evaluates to nothingness ("There was nothing
> > left...not even a hole!") actually does anything, then somebody in
> > the standards-compilers-users pipeline needs to be violently beaten
> > for stupidity.
>
>
> actually, one of the folks on the KJ list found this:
>
> http://www.ussg.iu.edu/hypermail/linux/kernel/9605/1957.html
>
> which speaks thusly:
>
> ...
> -#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
> -# define NORET_TYPE __volatile__
> -# define ATTRIB_NORET /**/
> -# define NORET_AND /**/
> -#else
> # define NORET_TYPE /**/
> # define ATTRIB_NORET __attribute__((noreturn))
> # define NORET_AND noreturn,
> -#endif
> ...
>
> so it looks like a thoroughly obsolete macro which can be tossed.
> i'll make the patch and test it.
AFAICT, NORET_TYPE must've been introduced to silence gcc _warnings_,
and not do actually do anything useful that affects functionality in any way.
So the way to "test" your patch would be to see if there is any increase /
decrease in the number of *warnings* blurted out by gcc during kernel build
(best would be to build with various gcc versions on various platforms :-)
But of course, John is *bang right* that if /**/ makes gcc do (or not do)
_anything at all_ (be it crying out a warning), then someone surely
deserves to get his head bashed in ... :-)
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