On Fri, Dec 10, 2021 at 12:23:59PM +0300, Dmitry Kozlyuk wrote:
> 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.
Sure. I wonder if it is worthwhile implementing both, since it's not a
large amount of code.
> Will Coverity understand that if a condition is always false,
> variables beneath still may be used on another platform?
That I don't know, unfortunately. Perhaps some coverity experts can weigh
in.
/Bruce
