Commit e6428c34 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

tools headers compiler: Pick the const_true() define from the kernel sources 



The sync of include/linux/bits.h with the kernel sources will make use
of this define, so add it to the tools/include/linux/compiler. variant
used to build tools/ living code.

Acked-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Acked-by: default avatarYury Norov [NVIDIA] <yury.norov@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20250519214126.1652491-7-acme@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent fa7a1e8d

tools/include/linux/compiler.h

+22 −0
Original line number Diff line number Diff line
@@ -81,6 +81,28 @@ 
#define __is_constexpr(x) \

	(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))



/*

 * Similar to statically_true() but produces a constant expression

 *

 * To be used in conjunction with macros, such as BUILD_BUG_ON_ZERO(),

 * which require their input to be a constant expression and for which

 * statically_true() would otherwise fail.

 *

 * This is a trade-off: const_true() requires all its operands to be

 * compile time constants. Else, it would always returns false even on

 * the most trivial cases like:

 *

 *   true || non_const_var

 *

 * On the opposite, statically_true() is able to fold more complex

 * tautologies and will return true on expressions such as:

 *

 *   !(non_const_var * 8 % 4)

 *

 * For the general case, statically_true() is better.

 */

#define const_true(x) __builtin_choose_expr(__is_constexpr(x), x, false)



#ifdef __ANDROID__

/*

 * FIXME: Big hammer to get rid of tons of: