blob: 94dea3ffbfa19576e2cd8bb59b56658465101b49 [file] [log] [blame]
Graeme Russ95ffaba2010-04-24 00:05:49 +10001#ifndef __LINUX_COMPILER_H
2#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
3#endif
4
5/* GCC 4.1.[01] miscompiles __weak */
6#ifdef __KERNEL__
7# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
8# error Your version of gcc miscompiles the __weak directive
9# endif
10#endif
11
12#define __used __attribute__((__used__))
13#define __must_check __attribute__((warn_unused_result))
14#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
15#define __always_inline inline __attribute__((always_inline))
16
17/*
18 * A trick to suppress uninitialized variable warning without generating any
19 * code
20 */
21#define uninitialized_var(x) x = x
22
23#if __GNUC_MINOR__ >= 3
24/* Mark functions as cold. gcc will assume any path leading to a call
25 to them will be unlikely. This means a lot of manual unlikely()s
26 are unnecessary now for any paths leading to the usual suspects
27 like BUG(), printk(), panic() etc. [but let's keep them for now for
28 older compilers]
29
30 Early snapshots of gcc 4.3 don't support this and we can't detect this
31 in the preprocessor, but we can live with this because they're unreleased.
32 Maketime probing would be overkill here.
33
34 gcc also has a __attribute__((__hot__)) to move hot functions into
35 a special section, but I don't see any sense in this right now in
36 the kernel context */
37#define __cold __attribute__((__cold__))
38
39
40#if __GNUC_MINOR__ >= 5
41/*
42 * Mark a position in code as unreachable. This can be used to
43 * suppress control flow warnings after asm blocks that transfer
44 * control elsewhere.
45 *
46 * Early snapshots of gcc 4.5 don't support this and we can't detect
47 * this in the preprocessor, but we can live with this because they're
48 * unreleased. Really, we need to have autoconf for the kernel.
49 */
50#define unreachable() __builtin_unreachable()
51#endif
52
53#endif
54
55#if __GNUC_MINOR__ > 0
56#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
57#endif
58#if __GNUC_MINOR__ >= 4
59#define __compiletime_warning(message) __attribute__((warning(message)))
60#define __compiletime_error(message) __attribute__((error(message)))
61#endif