Re: [PATCH] automation/eclair: deviate intentionally unreachable code

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 30/07/2025 3:06 pm, Dmytro Prokopchuk1 wrote:
> diff --git a/docs/misra/deviations.rst b/docs/misra/deviations.rst
> index e78179fcb8..fba75be2ee 100644
> --- a/docs/misra/deviations.rst
> +++ b/docs/misra/deviations.rst
> @@ -86,6 +86,14 @@ Deviations related to MISRA C:2012 Rules:
>         generate definitions for asm modules.
>       - Tagged as `deliberate` for ECLAIR.
>  
> +   * - R2.1
> +     - Calls to the `__builtin_unreachable` function inside the expansion of
> +       the `ASSERT_UNREACHABLE()` macro may cause a function to be marked as
> +       non-returning. Since this only happens in debug configurations,
> +       the `noreturn` property for `__builtin_unreachable` is overridden in
> +       these contexts, resulting in the absence of reports that do not have
> +       an impact on safety, despite being true positives.
> +

I'm not sure how best to phrase this, but it's probably worth saying
that Xen expects developers to write code which would fail safe in a
release build when the assertion was removed.

I.e. it's more than just "there may be code there".  It's expected that
there is.

~Andrew