Re: [XEN PATCH v4] automation/eclair: extend existing deviations of MISRA C Rule 16.3

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 25 Jun 2024, Jan Beulich wrote:
> On 25.06.2024 08:46, Federico Serafini wrote:
> > Update ECLAIR configuration to deviate more cases where an
> > unintentional fallthrough cannot happen.
> > 
> > Tag Rule 16.3 as clean for arm.
> > 
> > Signed-off-by: Federico Serafini <federico.serafini@xxxxxxxxxxx>
> > Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> 
> To add to my reply on the other series: As per above you even acked ...
> 
> > --- a/docs/misra/deviations.rst
> > +++ b/docs/misra/deviations.rst
> > @@ -330,12 +330,34 @@ Deviations related to MISRA C:2012 Rules:
> >       - Tagged as `deliberate` for ECLAIR.
> >  
> >     * - R16.3
> > -     - Switch clauses ending with continue, goto, return statements are 
> > safe.
> > +     - Statements that change the control flow (i.e., break, continue, 
> > goto,
> > +       return) and calls to functions that do not return the control back 
> > are
> > +       \"allowed terminal statements\".
> >       - Tagged as `safe` for ECLAIR.
> >  
> >     * - R16.3
> > -     - Switch clauses ending with a call to a function that does not give
> > -       the control back (i.e., a function with attribute noreturn) are 
> > safe.
> > +     - An if-else statement having both branches ending with one of the 
> > allowed
> > +       terminal statemets is itself an allowed terminal statements.
> > +     - Tagged as `safe` for ECLAIR.
> > +
> > +   * - R16.3
> > +     - An if-else statement having an always true condition and the true
> > +       branch ending with an allowed terminal statement is itself an 
> > allowed
> > +       terminal statement.
> > +     - Tagged as `safe` for ECLAIR.
> > +
> > +   * - R16.3
> > +     - A switch clause ending with a statement expression which, in turn, 
> > ends
> > +       with an allowed terminal statement (e.g., the expansion of
> > +       generate_exception()) is safe.
> > +     - Tagged as `safe` for ECLAIR.
> > +
> > +   * - R16.3
> > +     - A switch clause ending with a do-while-false the body of which, in 
> > turn,
> > +       ends with an allowed terminal statement (e.g., PARSE_ERR_RET()) is 
> > safe.
> > +       An exception to that is the macro ASSERT_UNREACHABLE() which is
> > +       effective in debug build only: a switch clause ending with
> > +       ASSERT_UNREACHABLE() is not considered safe.
> >       - Tagged as `safe` for ECLAIR.
> 
> ... this explicit statement regarding ASSERT_UNREACHABLE().

You are right... I read the statement about ASSERT_UNREACHABLE() only in
the context of do-while-false. Let's continue the discussion in the
other email thread.