Re: Conflict between sparse and commit cafa0010cd51f ("Raise the minimum required gcc version to 4.6")

[Christophe LEROY]

Le 07/09/2018 Ã 20:19, Nick Desaulniers a ÃcritÂ:
> On Fri, Sep 7, 2018 at 11:13 AM Luc Van Oostenryck
> <luc.vanoostenryck@xxxxxxxxx> wrote:
> > On Fri, Sep 07, 2018 at 10:22:56AM -0700, Nick Desaulniers wrote:
> > > On Fri, Sep 7, 2018 at 7:34 AM Christophe LEROY <christophe.leroy@xxxxxx> wrote:
> > > > Cc linux-sparse@xxxxxxxxxxxxxxx
> > > >
> > > > Le 07/09/2018 Ã 14:22, Christophe Leroy a Ãcrit :
> > > > > Since commit cafa0010cd51f ("Raise the minimum required gcc version to
> > > > > 4.6"), sparse check fails as follows:
> > > > >
> > > > > [root@pc16082vm linux-powerpc]# make C=2 arch/powerpc/kernel/process.o
> > > > >     CALL    scripts/checksyscalls.sh
> > > > >     CHECK   scripts/mod/empty.c
> > > > > ./include/linux/compiler-gcc.h:14:3: error: Sorry, your compiler is too
> > > > > old - please upgrade it.
> > > > >     CHECK   arch/powerpc/kernel/process.c
> > > > > ./include/linux/compiler-gcc.h:14:3: error: Sorry, your compiler is too
> > > > > old - please upgrade it.
> > > > >
> > > > >
> > > > > I have sparse version 0.5.2
> > > > >
> > > > > What can be done to fix that ?
> > > > >
> > > > > Christophe
> > >
> > > Oof, sorry Christophe.  Looks like that's the latest version of sparse:
> > > https://sparse.wiki.kernel.org/index.php/Main_Page#News
> > >
> > > I'm curious what sparse expands __GNUC__, __GNUC_MINOR__, and
> > > __GNUC_PATCHLEVEL__ to?  Pre commit cafa0010cd51f, it MUST be
> > > expanding them to something, otherwise you'd have seen the error then,
> > > too.  The previous check was GCC < 3.3, now it's GCC < 4.6.
> >
> > Sparse expand these macros to the same version than the compiler used
> > to compile GCC. I find a bit strange though to have sparse v0.5.2 but
> > using an old compiler.
>
> So Christophe must have a version of gcc < 4.6 installed somewhere?
> Does sparse use `cc`? If so, Christophe, does your `ls -l $(which cc)`
> point to an old version of gcc maybe?

Indeed it looks like sparse expand these macros to the version of the 
compiler it was compiled with.

I'm building kernels for a powerpc platforms, with CROSS_COMPILE set to 
ppc-linux- and ppc-linux-gcc being version 5.4

However my build machine is a CentOS6 and the native gcc has version 
4.4.7, so sparse expands that version.

Is there a way to get sparse in line with my cross compiler version and 
not with the local native version ?

Christophe

> > Also, it's worth to look at what is said in this email:
> >    https://lore.kernel.org/lkml/CA+55aFzYEnZR2GZLR-DwpONjMNYGYoDy+6AWLCVNayWiaZuqoA@xxxxxxxxxxxxxx/
> >
> >
> > -- Luc