Re: [PATCH 2/2] configure: Check -falign-jumps=1 -falign-functions=1 beside -falign-loops=1

[Paul Menzel]

Dear Fāng-ruì,


Am 24.08.21 um 08:18 schrieb Fangrui Song via Grub-devel:
> Clang does not support -falign-jumps and only recently gained support
> for -falign-loops. Test all the alignment options to avoid passing
> unrecognized options to Clang:
>
>      clang-14: error: optimization flag '-falign-jumps=1' is not supported 
> [-Werror,-Wignored-optimization-argument]
>
> When compiled with older Clang, the alignment options are not added, so
> just avoid the complexity for each option.
>
> Signed-off-by: Fangrui Song <maskray@google.com>
> ---
>   configure.ac | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 9a12151bd..8625e6776 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -798,8 +798,9 @@ fi
>   
>   # Force no alignment to save space on i386.
>   if test "x$target_cpu" = xi386; then
> -  AC_CACHE_CHECK([whether -falign-loops works], [grub_cv_cc_falign_loop], [
> -    CFLAGS="$TARGET_CFLAGS -falign-loops=1 -Werror"
> +  AC_CACHE_CHECK([whether -falign-jumps=1 -falign-loops=1 -falign-functions=1 
> works],
> +    [grub_cv_cc_falign_loop], [
> +    CFLAGS="$TARGET_CFLAGS -falign-jumps=1 -falign-loops=1 -falign-functions=1 
> -Werror"
>       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
>           [grub_cv_cc_falign_loop=yes],
>         [grub_cv_cc_falign_loop=no])

Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>


Kind regards,

Paul