ping
i'd like to see this change go in asap since it is pre-requisite to
turning on -Wvla which explicitly caught use of non-constant expressions
in the RTE_BUILD_BUG_ON() hiding bugs.
thanks!
On Mon, Nov 13, 2023 at 09:06:05AM -0800, Stephen Hemminger wrote:
> Both Gcc, clang and MSVC have better way to do compile time
> assertions rather than using out of bounds array access.
> The old method would fail if -Wvla is enabled because compiler
> can't determine size in that code. Also, the use of new
> _Static_assert will catch broken code that is passing non-constant
> expression to RTE_BUILD_BUG_ON().
>
> Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
> Acked-by: Morten Brørup <m...@smartsharesystems.com>
> Acked-by: Tyler Retzlaff <roret...@linux.microsoft.com>
> ---
> lib/eal/include/rte_common.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
> index c1ba32d00e47..bea7c0e57d5e 100644
> --- a/lib/eal/include/rte_common.h
> +++ b/lib/eal/include/rte_common.h
> @@ -16,6 +16,7 @@
> extern "C" {
> #endif
>
> +#include <assert.h>
> #include <stdint.h>
> #include <limits.h>
>
> @@ -495,7 +496,7 @@ rte_is_aligned(const void * const __rte_restrict ptr,
> const unsigned int align)
> /**
> * Triggers an error at compilation time if the condition is true.
> */
> -#define RTE_BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
> +#define RTE_BUILD_BUG_ON(condition) static_assert(!(condition), #condition)
>
> /*********** Cache line related macros ********/
>
> --
> 2.39.2
