Re: [PATCH 3/3] xen/MISRA: Remove nonstandard inline keywords

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

On 2023-11-22 17:46, Andrew Cooper wrote:
> On 22/11/2023 4:39 pm, Nicola Vetrini wrote:
> > On 2023-11-22 15:27, Andrew Cooper wrote:
> > > The differences between inline, __inline and __inline__ keywords are 
> > > a
> > > vestigial remnant of older C standards, and in Xen we use inline 
> > > almost
> > > exclusively.
> > >
> > > Replace __inline and __inline__ with regular inline, and remove their
> > > exceptions from the MISRA configuration.
> > >
> > > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> > > ---
> > > CC: Jan Beulich <JBeulich@xxxxxxxx>
> > > CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> > > CC: Wei Liu <wl@xxxxxxx>
> > > CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> > > CC: Roberto Bagnara <roberto.bagnara@xxxxxxxxxxx>
> > > CC: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> > > CC: Simone Ballarin <simone.ballarin@xxxxxxxxxxx>
> > >
> > > I'm entirely guessing at the Eclair configuration.
> > > ---
> > The configuration changes are ok. One observation below.
> Thanks.  Can I take that as an Ack/Reviewed-by ?
I see that Simone already gave one; that should suffice.

> > > diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h
> > > index 04b8bc18df0e..16d554f2a593 100644
> > > --- a/xen/include/xen/compiler.h
> > > +++ b/xen/include/xen/compiler.h
> > > @@ -83,7 +82,7 @@
> > >   * inline functions not expanded inline get placed in .init.text.
> > >   */
> > >  #include <xen/init.h>
> > > -#define __inline__ __inline__ __init
> > > +#define inline inline __init
> > The violation of Rule 20.4 (A macro shall not be defined with the same
> > name as a keyword) is still present due to this macro.
> I was expecting this to come up.
>
> There's a comment half out of context above, but to expand on it, we
> have a feature in the build system where if you say obj-y += foo.init.o
> then it gets compiled as normal and then all symbols checked for being
> in the relevant .init sections.  It's a safeguard around init-only code
> ending up in the runtime image (which is good for other goals of 
> safety).
> This particular define is necessary to cause out-of-lined static 
> inlines
> to end up in the right section, without having to invent a new
> __inline_or_init macro and rewriting half the header files in the 
> project.
> I think it's going to need a local deviation.  It's deliberate, and all
> we're doing is using the inline keyword to hook in an extra __section()
> attribute.
>
> ~Andrew
That's fair. I also agree that an exception for this use of inline can 
be made.
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)