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

[Nicola Vetrini <nicola.vetrini@bugseng.com>]

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@bugseng.com>
> 
> 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)