Re: [XEN PATCH 4/5] automation/eclair_analysis: address remaining violations of MISRA C Rule 20.12

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2024-06-03 23:24, Jan Beulich wrote:
> On 03.06.2024 21:12, Nicola Vetrini wrote:
> > On 2024-06-03 20:52, Jan Beulich wrote:
> > > On 03.06.2024 09:13, Nicola Vetrini wrote:
> > > > On 2024-06-03 07:58, Jan Beulich wrote:
> > > > > On 01.06.2024 12:16, Nicola Vetrini wrote:
> > > > > > --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
> > > > > > +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
> > > > > > @@ -483,6 +483,12 @@ leads to a violation of the Rule are 
> > > > > > deviated."
> > > > > >  -config=MC3R1.R20.12,macros+={deliberate,
> > > > > > "name(GENERATE_CASE)&&loc(file(deliberate_generate_case))"}
> > > > > >  -doc_end
> > > > > >
> > > > > > +-doc_begin="The macro DEFINE is defined and used in excluded 
> > > > > > files
> > > > > > asm-offsets.c.
> > > > > > +This may still cause violations if entities outside these files 
> > > > > > are
> > > > > > referred to
> > > > > > +in the expansion."
> > > > > > +-config=MC3R1.R20.12,macros+={deliberate,
> > > > > > "name(DEFINE)&&loc(file(asm_offsets))"}
> > > > > > +-doc_end
> > > > > Can you give an example of such a reference? Nothing _in_
> > > > > asm-offsets.c
> > > > > should be referenced, I'd think. Only stuff in asm-offsets.h as
> > > > > _generated
> > > > > from_ asm-offsets.c will, of course, be.
> > > > Perhaps I could have expressed that more clearly. What I meant is 
> > > > that
> > > > there are some arguments to DEFINE that are not part of 
> > > > asm-offsets.c,
> > > > therefore they end up in the violation report, but are not actually
> > > > relevant, because the macro DEFINE is actually what we want to
> > > > exclude.
> > > >
> > > > See for instance at the link below VCPU_TRAP_{NMI,MCE}, which are
> > > > defined in asm/domain.h and used as arguments to DEFINE inside
> > > > asm-offsets.c.
> > > >
> > > > https://saas.eclairit.com:3787/fs/var/local/eclair/XEN.ecdf/ECLAIR_normal/staging/X86_64-BUGSENG/676/PROJECT.ecd;/by_service/MC3R1.R20.12.html
> > > I'm afraid I still don't understand: The file being supposed to be
> > > excluded from scanning, why does it even show up in that report?
> > The report is made up of several source code locations. Three of them
> > are within asm-offsets.c, which is excluded from compliance but still
> > analyzed, but one references a macro definition in another file (e.g.,
> > VCPU_TRAP_NMI from asm/domain.h). So in this case the exclusion of
> > asm-offsets.c is not enough for the report not to be shown.
> But the (would-be-)violation is in asm-offsets.c. The other locations
> pointed at are providing context. To report a violation, it should be
> enough to exclude the file where the violation itself is?
In general that may not be the safest choice, or it can limit the 
granularity of the configuration (not in the specific case, but the 
mechanism is general).
It's a design aspect of the tool to show a report unless all its 
locations are not meant to be shown.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)