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 <[email protected]>
---
History:
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 {
unsigned int nr_subgroups;
};
-#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
+#define _INTC_ARRAY(a) a, sizeof(a) / (_Generic(a, \
+ typeof(NULL): (size_t)-1, \
+ default: sizeof(*a)))
#define INTC_HW_DESC(vectors, groups, mask_regs, \
prio_regs, sense_regs, ack_regs) \
Hi,
On 1/22/23 08:27, 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 <[email protected]>
There are lots of non-ASCII characters in the new patch. This is one example
from over 20,000 lines of warnings:
../include/linux/sh_intc.h:102:27: error: stray '\302' in program
102 | <U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0> default:<U+00A0><U+00A0><U+00A0><U+00A0><U+00A0><U+00A0> sizeof(*a)))
| ^~~~~~~~
With all of those changed to tabs or spaces:
Tested-by: Randy Dunlap <[email protected]> # build-tested
Thanks.
> ---
> History:
> 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 {
> unsigned int nr_subgroups;
> };
>
> -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a)
> +#define _INTC_ARRAY(a) a, sizeof(a) / (_Generic(a, \
> + typeof(NULL): (size_t)-1, \
> + default: sizeof(*a)))
>
> #define INTC_HW_DESC(vectors, groups, mask_regs, \
> prio_regs, sense_regs, ack_regs) \
>
--
~Randy