[mirror_frr.git] / lib / compiler.h

/*
 * Copyright (c) 2015-2017  David Lamparter, for NetDEF, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef _FRR_COMPILER_H
#define _FRR_COMPILER_H

#ifdef __cplusplus
extern "C" {
#endif

/* function attributes, use like
 *   void prototype(void) __attribute__((_CONSTRUCTOR(100)));
 */
#if defined(__clang__)
#if __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 5)
#  define _RET_NONNULL    , returns_nonnull
#endif
#if __has_attribute(fallthrough)
#  define _FALLTHROUGH __attribute__((fallthrough));
#endif
# define _CONSTRUCTOR(x)  constructor(x)
# define _DEPRECATED(x) deprecated(x)
# if __has_builtin(assume)
#  define assume(x) __builtin_assume(x)
# endif
#elif defined(__GNUC__)
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)
#  define _RET_NONNULL    , returns_nonnull
#endif
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
#  define _CONSTRUCTOR(x) constructor(x)
#  define _DESTRUCTOR(x)  destructor(x)
#  define _ALLOC_SIZE(x)  alloc_size(x)
#endif
#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
#  define _DEPRECATED(x) deprecated(x)
#  define assume(x) do { if (!(x)) __builtin_unreachable(); } while (0)
#endif
#if __GNUC__ < 5
#  define __has_attribute(x) 0
#endif
#if __GNUC__ >= 7
#  define _FALLTHROUGH __attribute__((fallthrough));
#endif
#endif

#if __has_attribute(hot)
#  define _OPTIMIZE_HOT __attribute__((hot))
#else
#  define _OPTIMIZE_HOT
#endif
#if __has_attribute(optimize)
#  define _OPTIMIZE_O3 __attribute__((optimize("3")))
#else
#  define _OPTIMIZE_O3
#endif
#define OPTIMIZE _OPTIMIZE_O3 _OPTIMIZE_HOT

#if !defined(__GNUC__)
#error module code needs GCC visibility extensions
#elif __GNUC__ < 4
#error module code needs GCC visibility extensions
#else
# define DSO_PUBLIC __attribute__ ((visibility ("default")))
# define DSO_SELF   __attribute__ ((visibility ("protected")))
# define DSO_LOCAL  __attribute__ ((visibility ("hidden")))
#endif

#ifdef __sun
/* Solaris doesn't do constructor priorities due to linker restrictions */
#undef _CONSTRUCTOR
#undef _DESTRUCTOR
#endif

/* fallback versions */
#ifndef _RET_NONNULL
# define _RET_NONNULL
#endif
#ifndef _CONSTRUCTOR
# define _CONSTRUCTOR(x) constructor
#endif
#ifndef _DESTRUCTOR
# define _DESTRUCTOR(x) destructor
#endif
#ifndef _ALLOC_SIZE
# define _ALLOC_SIZE(x)
#endif
#ifndef _FALLTHROUGH
#define _FALLTHROUGH
#endif
#ifndef _DEPRECATED
#define _DEPRECATED(x) deprecated
#endif
#ifndef assume
#define assume(x)
#endif

/* pure = function does not modify memory & return value is the same if
 * memory hasn't changed (=> allows compiler to optimize)
 *
 * Mostly autodetected by the compiler if function body is available (i.e.
 * static inline functions in headers).  Since that implies it should only be
 * used in headers for non-inline functions, the "extern" is included here.
 */
#define ext_pure	extern __attribute__((pure))

/* for helper functions defined inside macros */
#define macro_inline	static inline __attribute__((unused))
#define macro_pure	static inline __attribute__((unused, pure))

/*
 * for warnings on macros, put in the macro content like this:
 *   #define MACRO BLA CPP_WARN("MACRO has been deprecated")
 */
#define CPP_STR(X) #X

#if defined(__ICC)
#define CPP_NOTICE(text) _Pragma(CPP_STR(message __FILE__ ": " text))
#define CPP_WARN(text) CPP_NOTICE(text)

#elif (defined(__GNUC__)                                                       \
       && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)))           \
	|| (defined(__clang__)                                                 \
	    && (__clang_major__ >= 4                                           \
		|| (__clang_major__ == 3 && __clang_minor__ >= 5)))
#define CPP_WARN(text) _Pragma(CPP_STR(GCC warning text))
#define CPP_NOTICE(text) _Pragma(CPP_STR(message text))

#else
#define CPP_WARN(text)
#define CPP_NOTICE(text)
#endif

/* MAX / MIN are not commonly defined, but useful */
/* note: glibc sys/param.h has #define MIN(a,b) (((a)<(b))?(a):(b)) */
#ifdef MAX
#undef MAX
#endif
#define MAX(a, b)                                                              \
	({                                                                     \
		typeof(a) _max_a = (a);                                        \
		typeof(b) _max_b = (b);                                        \
		_max_a > _max_b ? _max_a : _max_b;                             \
	})
#ifdef MIN
#undef MIN
#endif
#define MIN(a, b)                                                              \
	({                                                                     \
		typeof(a) _min_a = (a);                                        \
		typeof(b) _min_b = (b);                                        \
		_min_a < _min_b ? _min_a : _min_b;                             \
	})

#ifndef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
#endif

/* this variant of container_of() retains 'const' on pointers without needing
 * to be told to do so.  The following will all work without warning:
 *
 * struct member *p;
 * const struct member *cp;
 *
 * const struct cont *x = container_of(cp, struct cont, member);
 * const struct cont *x = container_of(cp, const struct cont, member);
 * const struct cont *x = container_of(p,  struct cont, member);
 * const struct cont *x = container_of(p,  const struct cont, member);
 * struct cont *x       = container_of(p,  struct cont, member);
 *
 * but the following will generate warnings about stripping const:
 *
 * struct cont *x       = container_of(cp, struct cont, member);
 * struct cont *x       = container_of(cp, const struct cont, member);
 * struct cont *x       = container_of(p,  const struct cont, member);
 */
#ifdef container_of
#undef container_of
#endif
#define container_of(ptr, type, member)                                        \
	(__builtin_choose_expr(                                                \
		__builtin_types_compatible_p(typeof(&((type *)0)->member),     \
			typeof(ptr))                                           \
		    ||  __builtin_types_compatible_p(void *, typeof(ptr)),     \
		({                                                             \
			typeof(((type *)0)->member) *__mptr = (void *)(ptr);   \
			(type *)((char *)__mptr - offsetof(type, member));     \
		}),                                                            \
		({                                                             \
			typeof(((const type *)0)->member) *__mptr = (ptr);     \
			(const type *)((const char *)__mptr -                  \
					offsetof(type, member));               \
		})                                                             \
	))

#define container_of_null(ptr, type, member)                                   \
	({                                                                     \
		typeof(ptr) _tmp = (ptr);                                      \
		_tmp ? container_of(_tmp, type, member) : NULL;                \
	})

#define array_size(ar) (sizeof(ar) / sizeof(ar[0]))

#ifdef __cplusplus
}
#endif

#endif /* _FRR_COMPILER_H */
Commit	Line	Data
de1a880c DL	1	/*
	2	* Copyright (c) 2015-2017 David Lamparter, for NetDEF, Inc.
	3	*
	4	* Permission to use, copy, modify, and distribute this software for any
	5	* purpose with or without fee is hereby granted, provided that the above
	6	* copyright notice and this permission notice appear in all copies.
	7	*
	8	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	9	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	10	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	11	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	12	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	13	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	14	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	15	*/
	16
	17	#ifndef _FRR_COMPILER_H
	18	#define _FRR_COMPILER_H
	19
5e244469 RW	20	#ifdef __cplusplus
	21	extern "C" {
	22	#endif
	23
de1a880c DL	24	/* function attributes, use like
	25	* void prototype(void) __attribute__((_CONSTRUCTOR(100)));
	26	*/
	27	#if defined(__clang__)
996c9314	28	#if __clang_major__ > 3 \|\| (__clang_major__ == 3 && __clang_minor__ >= 5)
de1a880c	29	# define _RET_NONNULL , returns_nonnull
996c9314	30	#endif
bd27ea43 DL	31	#if __has_attribute(fallthrough)
	32	# define _FALLTHROUGH __attribute__((fallthrough));
	33	#endif
de1a880c	34	# define _CONSTRUCTOR(x) constructor(x)
bcea0c0f	35	# define _DEPRECATED(x) deprecated(x)
111a04f7 DL	36	# if __has_builtin(assume)
	37	# define assume(x) __builtin_assume(x)
	38	# endif
de1a880c	39	#elif defined(__GNUC__)
996c9314	40	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)
de1a880c	41	# define _RET_NONNULL , returns_nonnull
996c9314 LB	42	#endif
996c9314 LB	43	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
de1a880c DL	44	# define _CONSTRUCTOR(x) constructor(x)
	45	# define _DESTRUCTOR(x) destructor(x)
	46	# define _ALLOC_SIZE(x) alloc_size(x)
996c9314	47	#endif
bcea0c0f DL	48	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
bcea0c0f DL	49	# define _DEPRECATED(x) deprecated(x)
111a04f7 DL	50	# define assume(x) do { if (!(x)) __builtin_unreachable(); } while (0)
	51	#endif
	52	#if __GNUC__ < 5
	53	# define __has_attribute(x) 0
bcea0c0f	54	#endif
bd27ea43 DL	55	#if __GNUC__ >= 7
	56	# define _FALLTHROUGH __attribute__((fallthrough));
	57	#endif
de1a880c DL	58	#endif
de1a880c DL	59
111a04f7 DL	60	#if __has_attribute(hot)
	61	# define _OPTIMIZE_HOT __attribute__((hot))
	62	#else
	63	# define _OPTIMIZE_HOT
	64	#endif
	65	#if __has_attribute(optimize)
	66	# define _OPTIMIZE_O3 __attribute__((optimize("3")))
	67	#else
	68	# define _OPTIMIZE_O3
	69	#endif
	70	#define OPTIMIZE _OPTIMIZE_O3 _OPTIMIZE_HOT
	71
8be3678a DL	72	#if !defined(__GNUC__)
	73	#error module code needs GCC visibility extensions
	74	#elif __GNUC__ < 4
	75	#error module code needs GCC visibility extensions
	76	#else
	77	# define DSO_PUBLIC __attribute__ ((visibility ("default")))
	78	# define DSO_SELF __attribute__ ((visibility ("protected")))
	79	# define DSO_LOCAL __attribute__ ((visibility ("hidden")))
	80	#endif
	81
de1a880c DL	82	#ifdef __sun
de1a880c DL	83	/* Solaris doesn't do constructor priorities due to linker restrictions */
996c9314 LB	84	#undef _CONSTRUCTOR
996c9314 LB	85	#undef _DESTRUCTOR
de1a880c DL	86	#endif
	87
	88	/* fallback versions */
	89	#ifndef _RET_NONNULL
	90	# define _RET_NONNULL
	91	#endif
	92	#ifndef _CONSTRUCTOR
	93	# define _CONSTRUCTOR(x) constructor
	94	#endif
	95	#ifndef _DESTRUCTOR
	96	# define _DESTRUCTOR(x) destructor
	97	#endif
	98	#ifndef _ALLOC_SIZE
	99	# define _ALLOC_SIZE(x)
	100	#endif
bd27ea43 DL	101	#ifndef _FALLTHROUGH
	102	#define _FALLTHROUGH
	103	#endif
bcea0c0f DL	104	#ifndef _DEPRECATED
	105	#define _DEPRECATED(x) deprecated
	106	#endif
111a04f7 DL	107	#ifndef assume
	108	#define assume(x)
	109	#endif
de1a880c	110
3b18b6c0 DL	111	/* pure = function does not modify memory & return value is the same if
	112	* memory hasn't changed (=> allows compiler to optimize)
	113	*
	114	* Mostly autodetected by the compiler if function body is available (i.e.
	115	* static inline functions in headers). Since that implies it should only be
	116	* used in headers for non-inline functions, the "extern" is included here.
	117	*/
	118	#define ext_pure extern __attribute__((pure))
	119
0d019561 DL	120	/* for helper functions defined inside macros */
	121	#define macro_inline static inline __attribute__((unused))
	122	#define macro_pure static inline __attribute__((unused, pure))
	123
de1a880c DL	124	/*
	125	* for warnings on macros, put in the macro content like this:
	126	* #define MACRO BLA CPP_WARN("MACRO has been deprecated")
	127	*/
	128	#define CPP_STR(X) #X
	129
	130	#if defined(__ICC)
	131	#define CPP_NOTICE(text) _Pragma(CPP_STR(message __FILE__ ": " text))
	132	#define CPP_WARN(text) CPP_NOTICE(text)
	133
	134	#elif (defined(__GNUC__) \
	135	&& (__GNUC__ >= 5 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) \
	136	\|\| (defined(__clang__) \
	137	&& (__clang_major__ >= 4 \
	138	\|\| (__clang_major__ == 3 && __clang_minor__ >= 5)))
	139	#define CPP_WARN(text) _Pragma(CPP_STR(GCC warning text))
	140	#define CPP_NOTICE(text) _Pragma(CPP_STR(message text))
	141
	142	#else
	143	#define CPP_WARN(text)
ec40eaf9	144	#define CPP_NOTICE(text)
de1a880c DL	145	#endif
de1a880c DL	146
0d019561 DL	147	/* MAX / MIN are not commonly defined, but useful */
	148	/* note: glibc sys/param.h has #define MIN(a,b) (((a)<(b))?(a):(b)) */
	149	#ifdef MAX
	150	#undef MAX
	151	#endif
	152	#define MAX(a, b) \
	153	({ \
	154	typeof(a) _max_a = (a); \
	155	typeof(b) _max_b = (b); \
	156	_max_a > _max_b ? _max_a : _max_b; \
	157	})
	158	#ifdef MIN
	159	#undef MIN
	160	#endif
	161	#define MIN(a, b) \
	162	({ \
	163	typeof(a) _min_a = (a); \
	164	typeof(b) _min_b = (b); \
	165	_min_a < _min_b ? _min_a : _min_b; \
	166	})
	167
	168	#ifndef offsetof
	169	#ifdef __compiler_offsetof
	170	#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)
	171	#else
	172	#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
	173	#endif
	174	#endif
	175
	176	/* this variant of container_of() retains 'const' on pointers without needing
	177	* to be told to do so. The following will all work without warning:
	178	*
	179	* struct member *p;
	180	* const struct member *cp;
	181	*
	182	* const struct cont *x = container_of(cp, struct cont, member);
	183	* const struct cont *x = container_of(cp, const struct cont, member);
	184	* const struct cont *x = container_of(p, struct cont, member);
	185	* const struct cont *x = container_of(p, const struct cont, member);
	186	* struct cont *x = container_of(p, struct cont, member);
	187	*
	188	* but the following will generate warnings about stripping const:
	189	*
	190	* struct cont *x = container_of(cp, struct cont, member);
	191	* struct cont *x = container_of(cp, const struct cont, member);
	192	* struct cont *x = container_of(p, const struct cont, member);
	193	*/
	194	#ifdef container_of
	195	#undef container_of
	196	#endif
	197	#define container_of(ptr, type, member) \
	198	(__builtin_choose_expr( \
	199	__builtin_types_compatible_p(typeof(&((type *)0)->member), \
	200	typeof(ptr)) \
	201	\|\| __builtin_types_compatible_p(void *, typeof(ptr)), \
	202	({ \
	203	typeof(((type )0)->member) __mptr = (void *)(ptr); \
	204	(type )((char )__mptr - offsetof(type, member)); \
	205	}), \
	206	({ \
	207	typeof(((const type )0)->member) __mptr = (ptr); \
	208	(const type )((const char )__mptr - \
	209	offsetof(type, member)); \
	210	}) \
211	))
212
213	#define container_of_null(ptr, type, member) \
214	({ \
215	typeof(ptr) _tmp = (ptr); \
216	_tmp ? container_of(_tmp, type, member) : NULL; \
217	})
218
219	#define array_size(ar) (sizeof(ar) / sizeof(ar[0]))
220
5e244469 RW	221	#ifdef __cplusplus
	222	}
	223	#endif
	224
de1a880c	225	#endif /* _FRR_COMPILER_H */