From 3d43e5390d83a95b08d09e8b811523f2d99a092c Mon Sep 17 00:00:00 2001 From: David Kalnischkies Date: Fri, 22 Jan 2010 08:27:20 +0100 Subject: add a few gcc helpers, including [un]likely() and __deprecated --- apt-pkg/contrib/system.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'apt-pkg/contrib/system.h') diff --git a/apt-pkg/contrib/system.h b/apt-pkg/contrib/system.h index 7ec3d7feb..b57093b93 100644 --- a/apt-pkg/contrib/system.h +++ b/apt-pkg/contrib/system.h @@ -55,4 +55,26 @@ #define CLRFLAG(v,f) ((v) &=~FLAG(f)) #define CHKFLAG(v,f) ((v) & FLAG(f) ? true : false) +// some nice optional GNUC features +#if __GNUC__ >= 3 + #define __must_check __attribute__ ((warn_unused_result)) + #define __deprecated __attribute__ ((deprecated)) + /* likely() and unlikely() can be used to mark boolean expressions + as (not) likely true which will help the compiler to optimise */ + #define likely(x) __builtin_expect (!!(x), 1) + #define unlikely(x) __builtin_expect (!!(x), 0) +#else + #define __must_check /* no warn_unused_result */ + #define __deprecated /* no deprecated */ + #define likely(x) (x) + #define unlikely(x) (x) +#endif + +// cold functions are unlikely() to be called +#if (__GNUC__ == 4 && __GNUC_MINOR__ >= 3) || __GNUC__ > 4 + #define __cold __attribute__ ((__cold__)) +#else + #define __cold /* no cold marker */ +#endif + #endif -- cgit v1.2.3