Re: [PATCH v3 03/10] compiler-gcc{3,4}.h: Use GCC_VERSION macro

Josh Triplett
2012-10-24T21:49:12Z

On Wed, Oct 24, 2012 at 09:05:46PM +0200, Borislav Petkov wrote:
> On Wed, Oct 24, 2012 at 11:33:54AM -0500, danielfsantos@att.net wrote:
> > Using GCC_VERSION reduces complexity, is easier to read and is GCC's
> > recommended mechanism for doing version checks. (Just don't ask me why
> > they didn't define it in the first place.) This also makes it easy to
> > merge compiler-gcc{,3,4}.h should somebody want to.
> >
> > Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
> > Acked-by: David Rientjes <rientjes@google.com>
> > ---
> > include/linux/compiler-gcc3.h | 8 ++++----
> > include/linux/compiler-gcc4.h | 14 +++++++-------
> > 2 files changed, 11 insertions(+), 11 deletions(-)
> >
> > diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
> > index 37d4124..7d89feb 100644
> > --- a/include/linux/compiler-gcc3.h
> > +++ b/include/linux/compiler-gcc3.h
> > @@ -2,22 +2,22 @@
> > #error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
> > #endif
> >
> > -#if __GNUC_MINOR__ < 2
> > +#if GCC_VERSION < 30200
> > # error Sorry, your compiler is too old - please upgrade it.
> > #endif
> >
> > -#if __GNUC_MINOR__ >= 3
> > +#if GCC_VERSION >= 30300
> > # define __used __attribute__((__used__))
> > #else
> > # define __used __attribute__((__unused__))
> > #endif
> >
> > -#if __GNUC_MINOR__ >= 4
> > +#if GCC_VERSION >= 30400
> > #define __must_check __attribute__((warn_unused_result))
> > #endif
> >
> > #ifdef CONFIG_GCOV_KERNEL
> > -# if __GNUC_MINOR__ < 4
> > +# if GCC_VERSION < 30400
> > # error "GCOV profiling support for gcc versions below 3.4 not included"
> > # endif /* __GNUC_MINOR__ */
> > #endif /* CONFIG_GCOV_KERNEL */
> > diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
> > index 8914293..9755029 100644
> > --- a/include/linux/compiler-gcc4.h
> > +++ b/include/linux/compiler-gcc4.h
> > @@ -4,7 +4,7 @@
> >
> > /* GCC 4.1.[01] miscompiles __weak */
> > #ifdef __KERNEL__
> > -# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
> > +# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
> > # error Your version of gcc miscompiles the __weak directive
> > # endif
> > #endif
> > @@ -13,11 +13,11 @@
> > #define __must_check __attribute__((warn_unused_result))
> > #define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
> >
> > -#if __GNUC_MINOR__ > 0
> > +#if GCC_VERSION >= 40100
>
> I can't seem to recall so did we explain already why ">= 40100" instead
> of "> 40000"?
>
> I mean, it is the same, but still...

__GNUC_MINOR__ > 0 means __GNUC_MINOR__ >= 1, so that would allow 4.1 or
newer. However, GCC_VERSION > 40000 would also allow 4.0.n for n > 0.

- Josh Triplett