Fix: uatomic arm32: add missing release barrier before uatomic_xchg
[urcu.git] / include / urcu / compiler.h
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1#ifndef _URCU_COMPILER_H
2#define _URCU_COMPILER_H
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3
4/*
5 * compiler.h
6 *
7 * Compiler definitions.
8 *
6982d6d7 9 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
af02d47e 10 *
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11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this software and associated documentation files (the "Software"), to deal
13 * in the Software without restriction, including without limitation the rights
14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
15 * copies of the Software, and to permit persons to whom the Software is
16 * furnished to do so, subject to the following conditions:
af02d47e 17 *
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18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
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20 */
21
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22#include <stddef.h> /* for offsetof */
23
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24#define caa_likely(x) __builtin_expect(!!(x), 1)
25#define caa_unlikely(x) __builtin_expect(!!(x), 0)
2dc5fa0f 26
e51500ed 27#define cmm_barrier() __asm__ __volatile__ ("" : : : "memory")
2dc5fa0f 28
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29/*
30 * Instruct the compiler to perform only a single access to a variable
31 * (prohibits merging and refetching). The compiler is also forbidden to reorder
6cf3827c 32 * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of
af02d47e 33 * particular ordering. Compiler ordering can be ensured, for example, by
6cf3827c 34 * putting two CMM_ACCESS_ONCE() in separate C statements.
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35 *
36 * This macro does absolutely -nothing- to prevent the CPU from reordering,
37 * merging, or refetching absolutely anything at any time. Its main intended
38 * use is to mediate communication between process-level code and irq/NMI
39 * handlers, all running on the same CPU.
40 */
e51500ed 41#define CMM_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x))
af02d47e 42
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43#ifndef caa_max
44#define caa_max(a,b) ((a)>(b)?(a):(b))
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45#endif
46
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47#ifndef caa_min
48#define caa_min(a,b) ((a)<(b)?(a):(b))
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49#endif
50
1b27a772 51#if defined(__SIZEOF_LONG__)
06f22bdb 52#define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8)
1b27a772 53#elif defined(_LP64)
06f22bdb 54#define CAA_BITS_PER_LONG 64
1b27a772 55#else
06f22bdb 56#define CAA_BITS_PER_LONG 32
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57#endif
58
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59/*
60 * caa_container_of - Get the address of an object containing a field.
61 *
62 * @ptr: pointer to the field.
63 * @type: type of the object.
64 * @member: name of the field within the object.
65 */
66#define caa_container_of(ptr, type, member) \
1b85da85 67 __extension__ \
453629a9 68 ({ \
bdffa73a 69 const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
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70 (type *)((char *)__ptr - offsetof(type, member)); \
71 })
72
78bec10c 73#define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
9f59b220 74#define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
78bec10c 75
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76/*
77 * __rcu is an annotation that documents RCU pointer accesses that need
78 * to be protected by a read-side critical section. Eventually, a static
79 * checker will be able to use this annotation to detect incorrect RCU
80 * usage.
81 */
82#define __rcu
83
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84#ifdef __cplusplus
85#define URCU_FORCE_CAST(type, arg) (reinterpret_cast<type>(arg))
86#else
87#define URCU_FORCE_CAST(type, arg) ((type) (arg))
88#endif
89
4b5f005b 90#define caa_is_signed_type(type) ((type) -1 < (type) 0)
e56d99bf 91
4b5f005b 92/*
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93 * Cast to unsigned long, sign-extending if @v is signed.
94 * Note: casting to a larger type or to same type size keeps the sign of
95 * the expression being cast (see C99 6.3.1.3).
4b5f005b 96 */
e4749953 97#define caa_cast_long_keep_sign(v) ((unsigned long) (v))
e56d99bf 98
706d1165 99#if defined (__GNUC__) \
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100 && ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5) \
101 || __GNUC__ >= 5)
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102#define CDS_DEPRECATED(msg) \
103 __attribute__((deprecated(msg)))
104#else
105#define CDS_DEPRECATED(msg) \
106 __attribute__((deprecated))
107#endif
108
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109#define CAA_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
110
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111/*
112 * Don't allow compiling with buggy compiler.
113 */
114
115#ifdef __GNUC__
116# define URCU_GCC_VERSION (__GNUC__ * 10000 \
117 + __GNUC_MINOR__ * 100 \
118 + __GNUC_PATCHLEVEL__)
119
120/*
121 * http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58854
122 */
123# ifdef __ARMEL__
124# if URCU_GCC_VERSION >= 40800 && URCU_GCC_VERSION <= 40802
125# error Your gcc version produces clobbered frame accesses
126# endif
127# endif
128#endif
129
ec4e58a3 130#endif /* _URCU_COMPILER_H */
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