Re: [PATCH] bpf_helpers.h: define bpf_tail_call_static when building with GCC

[Yonghong Song <yonghong.song@linux.dev>]

On 1/23/24 10:59 AM, Jose E. Marchesi wrote:
> The definition of bpf_tail_call_static in tools/lib/bpf/bpf_helpers.h
> is guarded by a preprocessor check to assure that clang is recent
> enough to support it.  This patch updates the guard so the function is
> compiled when using GCC as well.
>
> Tested in bpf-next master.
> No regressions.
>
> Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
> Cc: Yonghong Song <yhs@meta.com>
> Cc: Eduard Zingerman <eddyz87@gmail.com>
> Cc: david.faust@oracle.com
> Cc: cupertino.miranda@oracle.com
> ---
>   tools/lib/bpf/bpf_helpers.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index 2324cc42b017..3306f50c5081 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -136,7 +136,7 @@
>   /*
>    * Helper function to perform a tail call with a constant/immediate map slot.
>    */
> -#if __clang_major__ >= 8 && defined(__bpf__)
> +#if (!defined(__clang__) || __clang_major__ >= 8) && defined(__bpf__)

Do you want to guard with a gcc version as well here or you assume any gcc which supports bpf
should be okay here?

>   static __always_inline void
>   bpf_tail_call_static(void *ctx, const void *map, const __u32 slot)
>   {