Re: [XEN PATCH v2 1/6][RESEND] automation/eclair: address violations of MISRA C Rule 20.7

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2024-06-21 02:18, Stefano Stabellini wrote:
> On Mon, 16 Jun 2024, Nicola Vetrini wrote:
> > MISRA C Rule 20.7 states: "Expressions resulting from the expansion
> > of macro parameters shall be enclosed in parentheses".
> >
> > The helper macro bitmap_switch has parameters that cannot be 
> > parenthesized
> > in order to comply with the rule, as that would break its 
> > functionality.
> > Moreover, the risk of misuse due developer confusion is deemed not
> > substantial enough to warrant a more involved refactor, thus the macro
> > is deviated for this rule.
> >
> > No functional change.
> >
> > Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> If possible, I would prefer we used a SAF in-code comment deviation. If
> that doesn't work for any reason this patch is fine and I'd ack it.
Would that be an improvement for safety in your opinion?

> > ---
> >  automation/eclair_analysis/ECLAIR/deviations.ecl | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl 
> > b/automation/eclair_analysis/ECLAIR/deviations.ecl
> > index 447c1e6661d1..c2698e7074aa 100644
> > --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
> > +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
> > @@ -463,6 +463,14 @@ of this macro do not lead to developer confusion, 
> > and can thus be deviated."
> >  -config=MC3R1.R20.7,reports+={safe, 
> > "any_area(any_loc(any_exp(macro(^count_args_$))))"}
> >  -doc_end
> >
> > +-doc_begin="The arguments of macro bitmap_switch macro can't be 
> > parenthesized as
> > +the rule would require, without breaking the functionality of the 
> > macro. This is
> > +a specialized local helper macro only used within the bitmap.h 
> > header, so it is
> > +less likely to lead to developer confusion and it is deemed better to 
> > deviate it."
> > +-file_tag+={xen_bitmap_h, "^xen/include/xen/bitmap\\.h$"}
> > +-config=MC3R1.R20.7,reports+={safe, 
> > "any_area(any_loc(any_exp(macro(loc(file(xen_bitmap_h))&&^bitmap_switch$))))"}
> > +-doc_end
> > +
> >  -doc_begin="Uses of variadic macros that have one of their arguments 
> > defined as
> >  a macro and used within the body for both ordinary parameter 
> > expansion and as an
> >  operand to the # or ## operators have a behavior that is 
> > well-understood and
> > --
> > 2.34.1
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)