Re: [PATCH 2/4] Eclair: relax long <-> function-pointer conversion deviation

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

On 2026-09-03 13:43, Jan Beulich wrote:
> What is true for unsigned long is also true for plain/signed long, thus
> also taking care of two instances of __x86_return_thunk() being cast to
> long.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Nicola Vetrini <nicola.vetrini@bugseng.com>

Some nits below:

> 
> --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
> +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
> @@ -368,17 +368,17 @@ constant expressions are required.\""
>  # Series 11
>  #
> 
> --doc_begin="The conversion from a function pointer to unsigned long or 
> (void *) does not lose any information, provided that the target type 
> has enough bits to store it."
> +-doc_begin="The conversion from a function pointer to [unsigned] long 
> or (void *) does not lose any information, provided that the target 
> type has enough bits to store it."
>  -config=MC3A2.R11.1,casts+={safe,
>    "from(type(canonical(__function_pointer_types)))
> -   &&to(type(canonical(builtin(unsigned 
> long)||pointer(builtin(void)))))
> +   &&to(type(canonical(builtin(long)||builtin(unsigned 
> long)||pointer(builtin(void)))))
>     &&relation(definitely_preserves_value)"
>  }

could be canonical(builtin(long||unsigned long))||pointer(builtin(void))

>  -doc_end
> 
> --doc_begin="Conversion from unsigned long or (void *) to a function 
> pointer can restore full information, provided that the source type has 
> enough bits to restore it."
> +-doc_begin="Conversion from [unsigned] long or (void *) to a function 
> pointer can restore full information, provided that the source type has 
> enough bits to restore it."
>  -config=MC3A2.R11.1,casts+={safe,
> -  "from(type(canonical(builtin(unsigned 
> long)||pointer(builtin(void)))))
> +  "from(type(canonical(builtin(long)||builtin(unsigned 
> long)||pointer(builtin(void)))))
>     &&to(type(canonical(__function_pointer_types)))
>     &&relation(definitely_preserves_value)"
>  }

Same as above

> --- a/docs/misra/rules.rst
> +++ b/docs/misra/rules.rst
> @@ -432,8 +432,8 @@ maintainers if you want to suggest a cha
>       - All conversions to integer types are permitted if the 
> destination
>         type has enough bits to hold the entire value. Conversions to 
> bool
>         and void* are permitted. Conversions from 'void noreturn 
> (*)(...)'
> -       to 'void (*)(...)' are permitted. Conversions from unsigned 
> long or
> -       '(void *)' to a function pointer are permitted.
> +       to 'void (*)(...)' are permitted. Conversions from [unsigned] 
> long
> +       or '(void *)' to a function pointer are permitted.
>         Example::
> 
>             unsigned long func_addr = (unsigned long)&some_function;

-- 
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253