Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 24 Jan 2023 14:07:54 +0100 | Subject | Re: [PATCH v4 1/1] arch/sh: avoid spurious sizeof-pointer-div warning |
| |
On Mon, Jan 23, 2023 at 8:40 PM Randy Dunlap <rdunlap@infradead.org> wrote: > I'm curious how you generated this patch. > 'patch' complains: > > patch: **** malformed patch at line 53: prio_regs, sense_regs, ack_regs) \ > > (more below) > > On 1/23/23 10:48, Michael Karcher wrote: > > Gcc warns about the pattern sizeof(void*)/sizeof(void), as it looks like > > the abuse of a pattern to calculate the array size. This pattern appears > > in the unevaluated part of the ternary operator in _INTC_ARRAY if the > > parameter is NULL. > > > > The replacement uses an alternate approach to return 0 in case of NULL > > which does not generate the pattern sizeof(void*)/sizeof(void), but still > > emits the warning if _INTC_ARRAY is called with a nonarray parameter. > > > > This patch is required for successful compilation with -Werror enabled. > > > > The idea to use _Generic for type distinction is taken from Comment #7 > > in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108483 by Jakub Jelinek > > > > Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de> > > --- > > This edition of the mail has the correct "v4" designation in the subject. > > > > History: > > v4: > > - Put the case distinction into the numerator instead of the denominator > > - Refactor the case disctinction into a second macro > > v3: > > - I had a stern discussion with Thunderbird about not mangling the > > space characters in my email, and I hope spaces get sent as standard > > spaces now > > v2: > > - improve title and remove mostly redundant first sentence of the > > description > > - adjust formatting of the _Generic construction > > > > diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h > > index c255273b0281..98d1da0d8e36 100644 > > --- a/include/linux/sh_intc.h > > +++ b/include/linux/sh_intc.h > > @@ -97,7 +97,9 @@ struct intc_hw_desc { > > That ,9 should be ,10.
Indeed.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Note that I didn't receive v5 (neither did lore), only Adrian's reply.
> > -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) > > +#define _INTC_SIZEOF_OR_ZERO(a) (_Generic(a, \ > > + typeof(NULL): 0, \ > > + default: sizeof(a)))
_INTC_SIZEOF_OR_ZERO() might be useful in general.
> > +#define _INTC_ARRAY(a) a, _INTC_SIZEOF_OR_ZERO(a)/sizeof(*a) > > > > #define INTC_HW_DESC(vectors, groups, mask_regs, \ > > prio_regs, sense_regs, ack_regs) \
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
| |