2 * Compiler specific macros.
4 * Copyright (C) 2013-2014 Simon Ruderich
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #ifdef HAVE___ATTRIBUTE__
24 /* Prevent/force inlining. Used to improve performance. */
25 # define noinline __attribute__((noinline))
26 # define always_inline __attribute__((always_inline))
27 /* Unused parameter. */
28 # define unused __attribute__((unused))
29 /* Mark the function protected, which means it can't be overwritten by other
30 * modules (libraries), e.g. with LD_PRELOAD); otherwise same as the default
31 * visibility. This causes the compiler not use the PLT (and no relocations)
32 * for local calls from inside this module; but the symbols are still
33 * exported. This is faster and in this case prevents useless lookups as we
34 * hook those functions and nobody else should modify them. Not strictly
35 * necessary, but nice to have. */
36 # define visibility_protected __attribute__((visibility("protected")))
39 # define always_inline
41 # define visibility_protected
44 /* Branch prediction information for the compiler. */
45 #ifdef HAVE___BUILTIN_EXPECT
46 # define likely(x) __builtin_expect(!!(x), 1)
47 # define unlikely(x) __builtin_expect(!!(x), 0)
50 # define unlikely(x) x