Messages in this thread | | | Date | Thu, 25 Aug 2022 17:04:26 +0900 | Subject | Re: [Intel-gfx] [PATCH v9 2/8] util_macros: Add exact_type macro to catch type mis-match while compiling | From | Gwan-gyeong Mun <> |
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Hi Bartosz Golaszewski,
would you mind taking a look at this patch?
Thanks, G.G.
On 8/24/22 5:45 PM, Gwan-gyeong Mun wrote: > It adds exact_type and exactly_pgoff_t macro to catch type mis-match while > compiling. The existing typecheck() macro outputs build warnings, but the > newly added exact_type() macro uses the BUILD_BUG_ON() macro to generate > a build break when the types are different and can be used to detect > explicit build errors. > > v6: Move macro addition location so that it can be used by other than drm > subsystem (Jani, Mauro, Andi) > > Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com> > Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> > Cc: Matthew Auld <matthew.auld@intel.com> > Cc: Nirmoy Das <nirmoy.das@intel.com> > Cc: Jani Nikula <jani.nikula@intel.com> > Cc: Andi Shyti <andi.shyti@linux.intel.com> > Cc: Mauro Carvalho Chehab <mchehab@kernel.org> > --- > include/linux/util_macros.h | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/include/linux/util_macros.h b/include/linux/util_macros.h > index 72299f261b25..b6624b275257 100644 > --- a/include/linux/util_macros.h > +++ b/include/linux/util_macros.h > @@ -2,6 +2,9 @@ > #ifndef _LINUX_HELPER_MACROS_H_ > #define _LINUX_HELPER_MACROS_H_ > > +#include <linux/types.h> > +#include <linux/bug.h> > + > #define __find_closest(x, a, as, op) \ > ({ \ > typeof(as) __fc_i, __fc_as = (as) - 1; \ > @@ -38,4 +41,26 @@ > */ > #define find_closest_descending(x, a, as) __find_closest(x, a, as, >=) > > +/** > + * exact_type - break compile if source type and destination value's type are > + * not the same > + * @T: Source type > + * @n: Destination value > + * > + * It is a helper macro for a poor man's -Wconversion: only allow variables of > + * an exact type. It determines whether the source type and destination value's > + * type are the same while compiling, and it breaks compile if two types are > + * not the same > + */ > +#define exact_type(T, n) \ > + BUILD_BUG_ON(!__builtin_constant_p(n) && !__builtin_types_compatible_p(T, typeof(n))) > + > +/** > + * exactly_pgoff_t - helper to check if the type of a value is pgoff_t > + * @n: value to compare pgoff_t type > + * > + * It breaks compile if the argument value's type is not pgoff_t type. > + */ > +#define exactly_pgoff_t(n) exact_type(pgoff_t, n) > + > #endif
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