Added two new compiler/optimizer hints: * The __rte_unreachable hint for use in points in code known never to be reached. * The __rte_assume hint for providing information about preconditions the compiler/optimizer might be unable to figure out by itself.
Signed-off-by: Morten Brørup <m...@smartsharesystems.com> --- lib/eal/include/rte_common.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h index c79f9ed319..2f143c87e4 100644 --- a/lib/eal/include/rte_common.h +++ b/lib/eal/include/rte_common.h @@ -366,6 +366,16 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) #define __rte_noreturn __attribute__((noreturn)) #endif +/** + * Hint point in program never reached + */ +#if defined(RTE_TOOLCHAIN_GCC) || defined(RTE_TOOLCHAIN_CLANG) +#define __rte_unreachable() __extension__(__builtin_unreachable()) +#else +/* MSVC or ICC */ +#define __rte_unreachable() __assume(0) +#endif + /** * Issue a warning in case the function's return value is ignored. * @@ -423,6 +433,23 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void) #define __rte_cold __attribute__((cold)) #endif +/** + * Hint precondition + * + * @warning Depending on the compiler, any code in ``condition`` might be executed. + * This currently only occurs with GCC prior to version 13. + */ +#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION >= 130000) +#define __rte_assume(condition) __attribute__((assume(condition))) +#elif defined(RTE_TOOLCHAIN_GCC) +#define __rte_assume(condition) do { if (!(condition)) __rte_unreachable(); } while (0) +#elif defined(RTE_TOOLCHAIN_CLANG) +#define __rte_assume(condition) __extension__(__builtin_assume(condition)) +#else +/* MSVC or ICC */ +#define __rte_assume(condition) __assume(condition) +#endif + /** * Disable AddressSanitizer on some code */ -- 2.43.0