blob: e057bd2a844d685b7b30b7f3de2f49a5a8495ccf [file] [log] [blame]
Graeme Russ95ffaba2010-04-24 00:05:49 +10001#ifndef __LINUX_COMPILER_H
2#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
3#endif
4
5/*
6 * Common definitions for all gcc versions go here.
7 */
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +09008#define GCC_VERSION (__GNUC__ * 10000 \
9 + __GNUC_MINOR__ * 100 \
10 + __GNUC_PATCHLEVEL__)
Graeme Russ95ffaba2010-04-24 00:05:49 +100011
12
13/* Optimization barrier */
14/* The "volatile" is due to gcc bugs */
15#define barrier() __asm__ __volatile__("": : :"memory")
16
17/*
18 * This macro obfuscates arithmetic on a variable address so that gcc
19 * shouldn't recognize the original var, and make assumptions about it.
20 *
21 * This is needed because the C standard makes it undefined to do
22 * pointer arithmetic on "objects" outside their boundaries and the
23 * gcc optimizers assume this is the case. In particular they
24 * assume such arithmetic does not wrap.
25 *
26 * A miscompilation has been observed because of this on PPC.
27 * To work around it we hide the relationship of the pointer and the object
28 * using this macro.
29 *
30 * Versions of the ppc64 compiler before 4.1 had a bug where use of
31 * RELOC_HIDE could trash r30. The bug can be worked around by changing
32 * the inline assembly constraint from =g to =r, in this particular
33 * case either is valid.
34 */
35#define RELOC_HIDE(ptr, off) \
36 ({ unsigned long __ptr; \
37 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
38 (typeof(ptr)) (__ptr + (off)); })
39
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090040/* Make the optimizer believe the variable can be manipulated arbitrarily. */
41#define OPTIMIZER_HIDE_VAR(var) __asm__ ("" : "=r" (var) : "0" (var))
42
43#ifdef __CHECKER__
44#define __must_be_array(arr) 0
45#else
Graeme Russ95ffaba2010-04-24 00:05:49 +100046/* &a[0] degrades to a pointer: a different type from an array */
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090047#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
48#endif
Graeme Russ95ffaba2010-04-24 00:05:49 +100049
50/*
51 * Force always-inline if the user requests it so via the .config,
52 * or if gcc is too old:
53 */
54#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
55 !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090056# define inline inline __attribute__((always_inline)) notrace
57# define __inline__ __inline__ __attribute__((always_inline)) notrace
58# define __inline __inline __attribute__((always_inline)) notrace
59#else
60/* A lot of inline functions can cause havoc with function tracing */
61# define inline inline notrace
62# define __inline__ __inline__ notrace
63# define __inline __inline notrace
Graeme Russ95ffaba2010-04-24 00:05:49 +100064#endif
65
66#define __deprecated __attribute__((deprecated))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +020067#ifndef __packed
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090068#define __packed __attribute__((packed))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +020069#endif
70#ifndef __weak
Graeme Russ95ffaba2010-04-24 00:05:49 +100071#define __weak __attribute__((weak))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +020072#endif
Graeme Russ95ffaba2010-04-24 00:05:49 +100073
74/*
75 * it doesn't make sense on ARM (currently the only user of __naked) to trace
76 * naked functions because then mcount is called without stack and frame pointer
77 * being set up and there is no chance to restore the lr register to the value
78 * before mcount was called.
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090079 *
80 * The asm() bodies of naked functions often depend on standard calling conventions,
81 * therefore they must be noinline and noclone. GCC 4.[56] currently fail to enforce
82 * this, so we must do so ourselves. See GCC PR44290.
Graeme Russ95ffaba2010-04-24 00:05:49 +100083 */
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090084#define __naked __attribute__((naked)) noinline __noclone notrace
Graeme Russ95ffaba2010-04-24 00:05:49 +100085
86#define __noreturn __attribute__((noreturn))
87
88/*
89 * From the GCC manual:
90 *
91 * Many functions have no effects except the return value and their
92 * return value depends only on the parameters and/or global
93 * variables. Such a function can be subject to common subexpression
94 * elimination and loop optimization just as an arithmetic operator
95 * would be.
96 * [...]
97 */
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +020098#ifndef __pure
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +090099#define __pure __attribute__((pure))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +0200100#endif
101#ifndef __aligned
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900102#define __aligned(x) __attribute__((aligned(x)))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +0200103#endif
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900104#define __printf(a, b) __attribute__((format(printf, a, b)))
105#define __scanf(a, b) __attribute__((format(scanf, a, b)))
Graeme Russ95ffaba2010-04-24 00:05:49 +1000106#define noinline __attribute__((noinline))
107#define __attribute_const__ __attribute__((__const__))
108#define __maybe_unused __attribute__((unused))
109#define __always_unused __attribute__((unused))
110
111#define __gcc_header(x) #x
112#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
113#define gcc_header(x) _gcc_header(x)
114#include gcc_header(__GNUC__)
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900115
116#if !defined(__noclone)
117#define __noclone /* not needed */
118#endif
119
120/*
121 * A trick to suppress uninitialized variable warning without generating any
122 * code
123 */
124#define uninitialized_var(x) x = x
125
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +0200126#ifndef __always_inline
Masahiro Yamadafb8ffd72014-09-04 02:40:58 +0900127#define __always_inline inline __attribute__((always_inline))
Jeroen Hofstee0a5051c2014-09-18 20:10:27 +0200128#endif