Re: [ndctl PATCH] util/size.h: Fix build error for GCC < 10

[Joao Martins <joao.m.martins@oracle.com>]

On 2/26/22 11:39, Vaibhav Jain wrote:
> Building with GCC 8.4.1 results in following build error for 'util/size.c':
> 
> ../util/size.h:57:16: error: missing binary operator before token "("
>    __has_builtin(__builtin_mul_overflow) && \
> 
> This is caused due to missing '__has_builtin' preprocessor operator in GCC
> versions < 10.0.0. The patch updates the check for CLANG's availability of
> __builtin_{mul,add}_overflow to prevent preprocessor from evaluating the
> expression "___has_builtin(__builtin_mul_overflow) &&
> __has_builtin(__builtin_add_overflow)".
> 
> Fixes:10653a171bc0("util/size.h: fix build for older compilers")
> Reported-by: Tarun Sahu <tsahu@linux.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>

> ---
>  util/size.h | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/util/size.h b/util/size.h
> index 1cb06690261b..02baa77fe649 100644
> --- a/util/size.h
> +++ b/util/size.h
> @@ -53,11 +53,12 @@ static inline bool is_power_of_2(unsigned long long v)
>  #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
>  #endif
>  
> -#if __clang__ && \
> -    __has_builtin(__builtin_mul_overflow) && \
> +#if __clang__
> +#if __has_builtin(__builtin_mul_overflow) && \
>      __has_builtin(__builtin_add_overflow)
>  #define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
>  #endif
> +#endif
>  
>  #if COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
>