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

[Thomas Monjalon <thomas@monjalon.net>]

04/05/2024 02:59, Stephen Hemminger:
> On Fri,  3 May 2024 19:27:30 +0100
> Daniel Gregory <daniel.gregory@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).
> 
> No, don't hide the problem.
> 
> What code is calling these. Looks like a real bug. Could be behind layers of wrappers.

I support Stephen's opinion.
Please look for the real issue.