Re: [PATCH v14 04/11] app/test: skip interrupt tests on Windows

[Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>]

2021-12-09 16:39 (UTC+0000), Bruce Richardson:
> On Thu, Dec 09, 2021 at 04:17:08PM +0000, Bruce Richardson wrote:
> [...]
> > I'm wondering if a reasonable compromise solution might be to have the
> > build system expose a usable RTE_EXEC_ENV symbol that can be used in C-code
> > if statements rather than just in ifdefs. That would allow us to easily add
> > e.g.
> > 
> > if (RTE_EXEC_ENV == rte_env_linux)
> >     return TEST_SKIPPED;
> > 
> > into each test function needing it. Two lines of C-code is a lot easier to
> > add and manage than #ifdefs covering the whole file, or alternative lists
> > in meson.
> >   
> Quick patch to allow C-code comparisons:
> 
> diff --git a/lib/eal/meson.build b/lib/eal/meson.build
> index 1722924f67..b5b9fa14b4 100644
> --- a/lib/eal/meson.build
> +++ b/lib/eal/meson.build
> @@ -10,6 +10,12 @@ if not is_windows
>      subdir('unix')
>  endif
>  
> +exec_envs = {'freebsd': 0, 'linux': 1, 'windows': 2}
> +foreach env, id:exec_envs
> +    dpdk_conf.set('RTE_ENV_' + env.to_upper(), id)
> +endforeach
> +dpdk_conf.set('RTE_EXEC_ENV', exec_envs[exec_env])
> +
>  dpdk_conf.set('RTE_EXEC_ENV_' + exec_env.to_upper(), 1)
>  subdir(exec_env)
> 
> A slightly simpler patch would just expose the environment as a string as
> e.g. "linux", but I think numeric ids just make the code better rather than
> having string comparisons. Alternatively, this could also be done via
> C-code with ifdefs in EAL, but as it stands this meson change allows:
> 
>   if (RTE_EXEC_ENV == RTE_ENV_WINDOWS)
>      ...
> 
> or:
> 
>   switch (RTE_EXEC_ENV) {
>     case RTE_ENV_LINUX: ... ; break;
>     case RTE_ENV_FREEBSD: ... ; break;
>     case RTE_ENV_WINDOWS: ... ; break;
>   }
> 
> Thoughts?

I like this.
Even outside of tests more code can be made to compile on all platforms
(e.g. ixgbe_wait_for_link_up).
Alternative naming: RTE_EXEC_ENV_IS_* (similar to RTE_CC_IS_*),
which does not allow switch statements, but shortens most practical cases.
Will Coverity understand that if a condition is always false,
variables beneath still may be used on another platform?