[Mesa-dev] [PATCH 1/5] mesa: bump required GCC version to 4.8.0

[Jonathan Gray]

LLVM was imported yes, but the integration of it has only
started around the same time and it is not enabled by default yet.
And it was only imported around two days or so ago.

And LLVM does not support all the architectures OpenBSD builds Mesa
on.

Can you point to something specific that needs a newer GCC version?
Do you want to target c++11 or the like?

We have patched the GCC included in the base tree multiple times
to support Mesa and could possibly do so again if you mention
specifics.

On Wed, Sep 07, 2016 at 02:28:16PM +1000, Timothy Arceri wrote:
> The last time this was bumped we settled on 4.2.0 because OpenBSD
> wasn't shipping anything greater than 4.2.1 (as that was the last
> GPLv2 licensed version) however they have now imported llvm to
> there base repo.
> 
> As far as I can tell the oldest distro still using a current version
> of Mesa is Red Hat Enterprise Linux 6 which ships with 4.4.7. However
> Dave reported that they build Mesa with GCC 4.8.
> 
> Cc: Jonathan Gray <jsg at jsg.id.au>
> ---
>  configure.ac         | 18 +++---------------
>  include/c99_compat.h | 17 +++++++----------
>  2 files changed, 10 insertions(+), 25 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index a413a3a..5128fc4 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -171,7 +171,6 @@ AC_MSG_RESULT([$acv_mesa_CLANG])
>  dnl If we're using GCC, make sure that it is at least version 4.2.0.  Older
>  dnl versions are explictly not supported.
>  GEN_ASM_OFFSETS=no
> -USE_GNU99=no
>  if test "x$GCC" = xyes -a "x$acv_mesa_CLANG" = xno; then
>      AC_MSG_CHECKING([whether gcc version is sufficient])
>      major=0
> @@ -183,16 +182,13 @@ if test "x$GCC" = xyes -a "x$acv_mesa_CLANG" = xno; then
>          GCC_VERSION_MINOR=`echo $GCC_VERSION | cut -d. -f2`
>      fi
>  
> -    if test $GCC_VERSION_MAJOR -lt 4 -o $GCC_VERSION_MAJOR -eq 4 -a $GCC_VERSION_MINOR -lt 2 ; then
> +    if test $GCC_VERSION_MAJOR -lt 4 -o $GCC_VERSION_MAJOR -eq 4 -a $GCC_VERSION_MINOR -lt 8 ; then
>          AC_MSG_RESULT([no])
> -        AC_MSG_ERROR([If using GCC, version 4.2.0 or later is required.])
> +        AC_MSG_ERROR([If using GCC, version 4.8.0 or later is required.])
>      else
>          AC_MSG_RESULT([yes])
>      fi
>  
> -    if test $GCC_VERSION_MAJOR -lt 4 -o $GCC_VERSION_MAJOR -eq 4 -a $GCC_VERSION_MINOR -lt 6 ; then
> -        USE_GNU99=yes
> -    fi
>      if test "x$cross_compiling" = xyes; then
>          GEN_ASM_OFFSETS=yes
>      fi
> @@ -269,12 +265,7 @@ AM_CONDITIONAL(HAVE_ANDROID, test "x$android" = xyes)
>  dnl Add flags for gcc and g++
>  if test "x$GCC" = xyes; then
>      CFLAGS="$CFLAGS -Wall"
> -
> -    if test "x$USE_GNU99" = xyes; then
> -	CFLAGS="$CFLAGS -std=gnu99"
> -    else
> -	CFLAGS="$CFLAGS -std=c99"
> -    fi
> +    CFLAGS="$CFLAGS -std=c99"
>  
>      # Enable -Werror=implicit-function-declaration and
>      # -Werror=missing-prototypes, if available, or otherwise, just
> @@ -401,9 +392,6 @@ AC_MSG_CHECKING(whether gcc supports -mpower8-vector)
>  save_CFLAGS=$CFLAGS
>  CFLAGS="$PWR8_CFLAGS $CFLAGS"
>  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
> -#if defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8))
> -#error "Need GCC >= 4.8 for sane POWER8 support"
> -#endif
>  #include <altivec.h>
>  int main () {
>      vector unsigned char r;
> diff --git a/include/c99_compat.h b/include/c99_compat.h
> index 24e96e0..d76171c 100644
> --- a/include/c99_compat.h
> +++ b/include/c99_compat.h
> @@ -145,8 +145,8 @@ test_c99_compat_h(const void * restrict a,
>  #  endif
>  
>  #  ifdef __GNUC__
> -#    if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 2)
> -#      error "GCC version 4.2 or higher required"
> +#    if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 8)
> +#      error "GCC version 4.8 or higher required"
>  #    endif
>  
>       /* https://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Other-Builtins.html */
> @@ -164,15 +164,12 @@ test_c99_compat_h(const void * restrict a,
>  #    define HAVE_FUNC_ATTRIBUTE_FORMAT 1
>  #    define HAVE_FUNC_ATTRIBUTE_PACKED 1
>  
> -#    if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
> -       /* https://gcc.gnu.org/onlinedocs/gcc-4.3.6/gcc/Other-Builtins.html */
> -#      define HAVE___BUILTIN_BSWAP32 1
> -#      define HAVE___BUILTIN_BSWAP64 1
> -#    endif
> +     /* https://gcc.gnu.org/onlinedocs/gcc-4.3.6/gcc/Other-Builtins.html */
> +#    define HAVE___BUILTIN_BSWAP32 1
> +#    define HAVE___BUILTIN_BSWAP64 1
>  
> -#    if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
> -#      define HAVE___BUILTIN_UNREACHABLE 1
> -#    endif
> +     /* GCC 4.5 */
> +#    define HAVE___BUILTIN_UNREACHABLE 1
>  
>  #  endif /* __GNUC__ */
>  
> -- 
> 2.7.4
>