Re: [XEN PATCH 5/5] xen: fix MISRA regressions on rule 20.9 and 20.12

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2024-06-01 14:47, Andrew Cooper wrote:
> On 01/06/2024 11:16 am, Nicola Vetrini wrote:
> > ea59e7d780d9 ("xen/bitops: Cleanup and new infrastructure ahead of 
> > rearrangements")
> > introduced new violations on previously clean rules 20.9 and 20.12.
> >
> > The first is introduced because CONFIG_CC_IS_CLANG in xen/self-tests.h 
> > is not
> > defined in the configuration under analysis. Using "defined()" instead 
> > avoids
> > relying on the preprocessor's behaviour upon encountering an 
> > undedfined identifier
> > and addresses the violation.
> >
> > The violation of Rule 20.12 is due to "val" being used both as an 
> > ordinary argument
> > in macro RUNTIME_CHECK, and as a stringification operator.
> >
> > No functional change.
> >
> > Fixes: ea59e7d780d9 ("xen/bitops: Cleanup and new infrastructure ahead 
> > of rearrangements")
> > Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> Thankyou for this patch.  I'd seen that I'd broken something.  
> (Entirely
> my fault - I've done a lot of testing in Gitlab for the series, but
> never manually ran the Eclair jobs.  I'll try to remember better next 
> time.)
> One question though. 
> https://gitlab.com/xen-project/xen/-/jobs/6994213979 says:
>
> Failure: 1 regressions found for clean guidelines
>   service MC3R1.R20.9: (required) All identifiers used in the
> controlling expression of `#if' or `#elif' preprocessing directives
> shall be #define'd before evaluation:
>    violation: 1
>
> While there is a report for 20.12, it's not clean yet (so the first
> sentence wants adjusting), and RUNTIME_CHECK doesn't show up newly in 
> it.
> So, while I agree that RUNTIME_CHECK() should be included in the 20.12
> exclusions, why is current Gitlab Run not reporting it?
>
> ~Andrew
While Rule 20.12 wasn't clean on x86, but it was on arm, so in the arm64 
run it is reported as such
https://gitlab.com/xen-project/xen/-/jobs/6994213980

with the other patches in the series the rule should be clean on both 
architectures, so this imbalance should disappear rather shortly.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)