blob: cdf13ca7cac32b61e07dcdbc9f9a79c68dd9ee3e [file] [log] [blame]
Robert P. J. Day94f582f2007-10-16 23:26:11 -07001#ifndef __LINUX_COMPILER_H
2#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
3#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07004
5/*
6 * Common definitions for all gcc versions go here.
7 */
Daniel Santos3f3f8d22013-02-21 16:41:39 -08008#define GCC_VERSION (__GNUC__ * 10000 \
9 + __GNUC_MINOR__ * 100 \
10 + __GNUC_PATCHLEVEL__)
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
12
13/* Optimization barrier */
14/* The "volatile" is due to gcc bugs */
15#define barrier() __asm__ __volatile__("": : :"memory")
16
Anton Blanchardc8d52462006-01-10 18:21:20 +110017/*
Andi Kleen85c210e2009-01-09 16:40:53 -080018 * 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 *
Anton Blanchardc8d52462006-01-10 18:21:20 +110030 * 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#define RELOC_HIDE(ptr, off) \
36 ({ unsigned long __ptr; \
Anton Blanchardc8d52462006-01-10 18:21:20 +110037 __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 (typeof(ptr)) (__ptr + (off)); })
Andrew Mortona1365642006-01-08 01:04:09 -080039
Cesar Eduardo Barrosfe8c8a12013-11-25 22:00:41 -020040/* Make the optimizer believe the variable can be manipulated arbitrarily. */
41#define OPTIMIZER_HIDE_VAR(var) __asm__ ("" : "=r" (var) : "0" (var))
42
KOSAKI Motohiro5bd7e6a2011-05-24 17:13:17 -070043#ifdef __CHECKER__
44#define __must_be_array(arr) 0
45#else
Rusty Russellc5e631cf2007-05-06 14:51:05 -070046/* &a[0] degrades to a pointer: a different type from an array */
Rusty Russellea6b1012010-08-09 17:20:18 -070047#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
KOSAKI Motohiro5bd7e6a2011-05-24 17:13:17 -070048#endif
Andrew Mortona1365642006-01-08 01:04:09 -080049
Ingo Molnar60a3cdd2008-03-03 12:38:52 +010050/*
Ingo Molnarae3a0062008-04-30 00:15:31 +020051 * Force always-inline if the user requests it so via the .config,
52 * or if gcc is too old:
Ingo Molnar60a3cdd2008-03-03 12:38:52 +010053 */
Ingo Molnar765c68b2008-04-09 11:03:37 +020054#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
Ingo Molnarae3a0062008-04-30 00:15:31 +020055 !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
Steven Rostedt93b3cca2012-06-14 10:54:28 -040056# define inline inline __attribute__((always_inline)) notrace
57# define __inline__ __inline__ __attribute__((always_inline)) notrace
58# define __inline __inline __attribute__((always_inline)) notrace
Steven Rostedt45959ee2011-12-12 15:22:41 -050059#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
Ingo Molnar60a3cdd2008-03-03 12:38:52 +010064#endif
65
Andrew Mortona1365642006-01-08 01:04:09 -080066#define __deprecated __attribute__((deprecated))
Robert P. J. Day82ddcb02007-02-10 01:46:20 -080067#define __packed __attribute__((packed))
68#define __weak __attribute__((weak))
Andrey Ryabinincb4188a2015-02-13 14:39:14 -080069#define __alias(symbol) __attribute__((alias(#symbol)))
Uwe Kleine-König446c92b2009-03-12 18:03:16 +010070
71/*
72 * it doesn't make sense on ARM (currently the only user of __naked) to trace
73 * naked functions because then mcount is called without stack and frame pointer
74 * being set up and there is no chance to restore the lr register to the value
75 * before mcount was called.
Mikael Pettersson9c695202010-06-29 15:05:25 -070076 *
77 * The asm() bodies of naked functions often depend on standard calling conventions,
78 * therefore they must be noinline and noclone. GCC 4.[56] currently fail to enforce
79 * this, so we must do so ourselves. See GCC PR44290.
Uwe Kleine-König446c92b2009-03-12 18:03:16 +010080 */
Mikael Pettersson9c695202010-06-29 15:05:25 -070081#define __naked __attribute__((naked)) noinline __noclone notrace
Uwe Kleine-König446c92b2009-03-12 18:03:16 +010082
Robert P. J. Day82ddcb02007-02-10 01:46:20 -080083#define __noreturn __attribute__((noreturn))
Ralf Baechlee8c44312007-10-18 03:07:07 -070084
85/*
86 * From the GCC manual:
87 *
88 * Many functions have no effects except the return value and their
89 * return value depends only on the parameters and/or global
90 * variables. Such a function can be subject to common subexpression
91 * elimination and loop optimization just as an arithmetic operator
92 * would be.
93 * [...]
94 */
Robert P. J. Day82ddcb02007-02-10 01:46:20 -080095#define __pure __attribute__((pure))
96#define __aligned(x) __attribute__((aligned(x)))
Joe Perches6061d942012-03-23 15:02:16 -070097#define __printf(a, b) __attribute__((format(printf, a, b)))
98#define __scanf(a, b) __attribute__((format(scanf, a, b)))
Andrew Mortona1365642006-01-08 01:04:09 -080099#define noinline __attribute__((noinline))
Andrew Mortona1365642006-01-08 01:04:09 -0800100#define __attribute_const__ __attribute__((__const__))
David Rientjes0d7ebbb2007-05-09 02:35:27 -0700101#define __maybe_unused __attribute__((unused))
Li Zefan7b2a3512009-11-02 08:50:52 +0800102#define __always_unused __attribute__((unused))
Linus Torvaldsf153b822009-01-02 09:23:03 -0800103
104#define __gcc_header(x) #x
105#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
106#define gcc_header(x) _gcc_header(x)
107#include gcc_header(__GNUC__)
Mikael Pettersson9c695202010-06-29 15:05:25 -0700108
109#if !defined(__noclone)
110#define __noclone /* not needed */
111#endif
Borislav Petkovc837fb32011-03-22 16:33:55 -0700112
113/*
114 * A trick to suppress uninitialized variable warning without generating any
115 * code
116 */
117#define uninitialized_var(x) x = x
118
119#define __always_inline inline __attribute__((always_inline))