[PATCH v2] eal/arm: replace RTE_BUILD_BUG on non-constant

[Stephen Hemminger]

On Fri,  3 May 2024 19:27:30 +0100
Daniel Gregory <daniel.gregory at bytedance.com> wrote:

> The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
> memorder, which is not constant. This causes compile errors when it is
> enabled with RTE_ARM_USE_WFE. eg.
> 
> ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
>   530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
>       |                                                        ^~~~~~~~~~~~
> ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
>   156 |         RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
>       |         ^~~~~~~~~~~~~~~~
> 
> Fix the compile errors by replacing the check with an assert, like in
> the generic implementation (lib/eal/include/generic/rte_pause.h).
> 
> Fixes: 875f350924b8 ("eal: add a new helper for wait until scheme")
> 
> Signed-off-by: Daniel Gregory <daniel.gregory at bytedance.com>
> ---
> Cc: feifei.wang2 at arm.com
> ---
>  lib/eal/arm/include/rte_pause_64.h | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/eal/arm/include/rte_pause_64.h b/lib/eal/arm/include/rte_pause_64.h
> index 5cb8b59056..852660091a 100644
> --- a/lib/eal/arm/include/rte_pause_64.h
> +++ b/lib/eal/arm/include/rte_pause_64.h
> @@ -10,6 +10,8 @@
>  extern "C" {
>  #endif
>  
> +#include <assert.h>
> +
>  #include <rte_common.h>
>  
>  #ifdef RTE_ARM_USE_WFE
> @@ -153,7 +155,7 @@ rte_wait_until_equal_16(volatile uint16_t *addr, uint16_t expected,
>  {
>  	uint16_t value;
>  
> -	RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> +	assert(memorder != rte_memory_order_acquire &&
>  		memorder != rte_memory_order_relaxed);
>  

Why not change RET_BUILD_BUG_ON() to RTE_ASSERT()?
The one issue is that by default RTE_ENABLE_ASSERT is not enabled.