Re: [Qemu-block] [Qemu-devel] [PATCH v9 15/37] qom: Swap 'name' next to visitor in ObjectPropertyAccessor

[Kevin Wolf]

Am 21.01.2016 um 10:18 hat Markus Armbruster geschrieben:
> Eric Blake <address@hidden> writes:
> > On 01/20/2016 11:49 AM, Markus Armbruster wrote:
> >> Eric Blake <address@hidden> writes:
> >> 
> >> However, the actual match is looser!  For instance, it also matches
> >> 
> >>     void foo(int *pi, unsigned *pu, void *vp, const char *cp, double **dpp)
> >>     {
> >>     }
> >
> > Uggh. My intent was to match exactly 'Object *' and 'Visitor *' as the
> > first two types, where 'int *' and 'unsigned *' are NOT matches.  But I
> > don't know Coccinelle well enough to make that blatantly obvious (is my
> > declaration of 'type Object' not correct?).
> 
> 'type Object' makes 'Object' a metavariable matching any C type.

I can't say anything on this one, because I've never used 'type'. You
may or may not be right. However...

> >> This could mess up unrelated function.  I could double-check it doesn't,
> >> but I'd rather have a narrower match instead.  Can't give one offhand,
> >> though.  Ideas?
> >
> > Is 'typedef' better than 'type' for constraining the type of the first
> > two arguments?
> 
> Matches any C typedef name.  Less wrong, but still wrong :)

...I'm pretty sure that this is wrong and 'typedef' only declares that a
specific type exists as a typedef.

> >                 Or does Coccinelle do literal matches on anything you
> > don't pre-declare, as in:
> 
> Yes, but...
> 
> >      @ rule1 @
> >      identifier fn;
> >      identifier obj, v, opaque, name, errp;
> >      @@
> >       void fn
> >      - (Object *obj, Visitor *v, void *opaque, const char *name,
> >      + (Object *obj, Visitor *v, const char *name, void *opaque,
> >         Error **errp) { ... }
> 
> ... when I try that, spatch throws a parse error.

Because you need to declare the typedef. :-)

I had a similar problem and asked Julia about it at KVM Forum, so I'm
pretty sure that it's right.

Kevin