Re: [XEN PATCH 7/7] vsprintf: address violations of MISRA C:2012 Rule 16.3

[Federico Serafini <federico.serafini@xxxxxxxxxxx>]

On 03/04/24 09:06, Jan Beulich wrote:
> On 02.04.2024 09:22, Federico Serafini wrote:
> > MISRA C:2012 Rule 16.3 states: "An unconditional `break' statement
> > shall terminate every switch-clause".
> >
> > Add break statement to address violations of the rule or add
> > pseudo-keyword fallthrough to meet the requirements to deviate it.
> While the latter half of the sentence properly describes the latter
> two of the hunks, the former half doesn't match the former two hunks
> at all:
>
> > --- a/xen/common/vsprintf.c
> > +++ b/xen/common/vsprintf.c
> > @@ -377,7 +377,7 @@ static char *pointer(char *str, const char *end, const char 
> > **fmt_ptr,
> >               str = number(str, end, hex_buffer[i], 16, 2, -1, ZEROPAD);
> >   
> >               if ( ++i == field_width )
> > -                return str;
> > +                break;
> This "break" is inside for(), not switch().
>
> > @@ -386,6 +386,8 @@ static char *pointer(char *str, const char *end, const char 
> > **fmt_ptr,
> >                   ++str;
> >               }
> >           }
> > +
> > +        return str;
> >       }
> And this "return" is what now "delimits" case 'h' of the switch(). The
> original situation therefore was that the for() could not be exited by
> other than the "return" inside. The supposedly missing "break" in that
> arrangement would have been "unreachable code", i.e. violate another
> rule. Hence the (undescribed) further re-arrangement.
I'll improve the description.

--
Federico Serafini, M.Sc.

Software Engineer, BUGSENG (http://bugseng.com)