[PATCH v5 02/39] eal: redefine macro to be integer literal for MSVC

[Konstantin Ananyev]

> MSVC __declspec(align(#)) is limited and accepts only integer literals
> as opposed to constant expressions. define XMM_SIZE to be 16 instead of
> sizeof(xmm_t) and static_assert that sizeof(xmm_t) == 16 for
> compatibility.
> 
> Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
> Acked-by: Morten Brørup <mb at smartsharesystems.com>
> ---
>  lib/eal/x86/include/rte_vect.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/eal/x86/include/rte_vect.h b/lib/eal/x86/include/rte_vect.h
> index a1a537e..441f1a0 100644
> --- a/lib/eal/x86/include/rte_vect.h
> +++ b/lib/eal/x86/include/rte_vect.h
> @@ -11,6 +11,7 @@
>   * RTE SSE/AVX related header.
>   */
> 
> +#include <assert.h>
>  #include <stdint.h>
>  #include <rte_config.h>
>  #include <rte_common.h>
> @@ -33,9 +34,11 @@
> 
>  typedef __m128i xmm_t;
> 
> -#define	XMM_SIZE	(sizeof(xmm_t))
> +#define	XMM_SIZE	16
>  #define	XMM_MASK	(XMM_SIZE - 1)
> 
> +static_assert(sizeof(xmm_t) == 16, "");

I think it is better be:
static_assert(sizeof(xmm_t) == XMM_SIZE, "");


BTW, is there any chance that in future versions MSVC would accept align(<constant_expression>)?

> +
>  typedef union rte_xmm {
>  	xmm_t    x;
>  	uint8_t  u8[XMM_SIZE / sizeof(uint8_t)];
> --
> 1.8.3.1