Re: [PATCH v4] Add pragma to ignore gcc-compat warnings in clang when used with diagnose_if.

[Ray Kinsella <mdr@ashroe.eu>]

Michael Barker <mikeb01@gmail.com> writes:

> When compiling with clang using -Wall (or -Wgcc-compat) the use of
> diagnose_if kicks up a warning:
>
> .../include/rte_interrupts.h:623:1: error: 'diagnose_if' is a clang
> extension [-Werror,-Wgcc-compat]
> __rte_internal
> ^
> .../include/rte_compat.h:36:16: note: expanded from macro '__rte_internal'
> __attribute__((diagnose_if(1, "Symbol is not public ABI", "error"), \
>
> This change ignores the '-Wgcc-compat' warning in the specific location
> where the warning occurs.  It is safe to do in this circumstance as the
> specific macro is only defined when using the clang compiler.
>
> Signed-off-by: Michael Barker <mikeb01@gmail.com>
> ---
>  lib/eal/include/rte_compat.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/lib/eal/include/rte_compat.h b/lib/eal/include/rte_compat.h
> index 2718612cce..9556bbf4d0 100644
> --- a/lib/eal/include/rte_compat.h
> +++ b/lib/eal/include/rte_compat.h
> @@ -33,8 +33,11 @@ section(".text.internal")))
>  #elif !defined ALLOW_INTERNAL_API && __has_attribute(diagnose_if) /*
> For clang */

Why doesn't the __has_attribute take care of this?
I would have thought that gcc would check the for the attribute, find it
doesn't support it and ignore the whole thing?

>  
>  #define __rte_internal \
> +_Pragma("GCC diagnostic push") \
> +_Pragma("GCC diagnostic ignored \"-Wgcc-compat\"") \
>  __attribute__((diagnose_if(1, "Symbol is not public ABI", "error"), \
> -section(".text.internal")))
> +section(".text.internal"))) \
> +_Pragma("GCC diagnostic pop")
>  
>  #else


-- 
Regards, Ray K