[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)
#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)
#endif
#if __GNUC__ >= 7
#  define _FALLTHROUGH __attribute__((fallthrough));
#endif
#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

/* 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)
de1a880c	36	#elif defined(__GNUC__)
996c9314	37	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)
de1a880c	38	# define _RET_NONNULL , returns_nonnull
996c9314 LB	39	#endif
996c9314 LB	40	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
de1a880c DL	41	# define _CONSTRUCTOR(x) constructor(x)
	42	# define _DESTRUCTOR(x) destructor(x)
	43	# define _ALLOC_SIZE(x) alloc_size(x)
996c9314	44	#endif
bcea0c0f DL	45	#if __GNUC__ > 4 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
	46	# define _DEPRECATED(x) deprecated(x)
	47	#endif
bd27ea43 DL	48	#if __GNUC__ >= 7
	49	# define _FALLTHROUGH __attribute__((fallthrough));
	50	#endif
de1a880c DL	51	#endif
	52
	53	#ifdef __sun
	54	/* Solaris doesn't do constructor priorities due to linker restrictions */
996c9314 LB	55	#undef _CONSTRUCTOR
996c9314 LB	56	#undef _DESTRUCTOR
de1a880c DL	57	#endif
	58
	59	/* fallback versions */
	60	#ifndef _RET_NONNULL
	61	# define _RET_NONNULL
	62	#endif
	63	#ifndef _CONSTRUCTOR
	64	# define _CONSTRUCTOR(x) constructor
	65	#endif
	66	#ifndef _DESTRUCTOR
	67	# define _DESTRUCTOR(x) destructor
	68	#endif
	69	#ifndef _ALLOC_SIZE
	70	# define _ALLOC_SIZE(x)
	71	#endif
bd27ea43 DL	72	#ifndef _FALLTHROUGH
	73	#define _FALLTHROUGH
	74	#endif
bcea0c0f DL	75	#ifndef _DEPRECATED
	76	#define _DEPRECATED(x) deprecated
	77	#endif
de1a880c	78
3b18b6c0 DL	79	/* pure = function does not modify memory & return value is the same if
	80	* memory hasn't changed (=> allows compiler to optimize)
	81	*
	82	* Mostly autodetected by the compiler if function body is available (i.e.
	83	* static inline functions in headers). Since that implies it should only be
	84	* used in headers for non-inline functions, the "extern" is included here.
	85	*/
	86	#define ext_pure extern __attribute__((pure))
	87
0d019561 DL	88	/* for helper functions defined inside macros */
	89	#define macro_inline static inline __attribute__((unused))
	90	#define macro_pure static inline __attribute__((unused, pure))
	91
de1a880c DL	92	/*
	93	* for warnings on macros, put in the macro content like this:
	94	* #define MACRO BLA CPP_WARN("MACRO has been deprecated")
	95	*/
	96	#define CPP_STR(X) #X
	97
	98	#if defined(__ICC)
	99	#define CPP_NOTICE(text) _Pragma(CPP_STR(message __FILE__ ": " text))
	100	#define CPP_WARN(text) CPP_NOTICE(text)
	101
	102	#elif (defined(__GNUC__) \
	103	&& (__GNUC__ >= 5 \|\| (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) \
	104	\|\| (defined(__clang__) \
	105	&& (__clang_major__ >= 4 \
	106	\|\| (__clang_major__ == 3 && __clang_minor__ >= 5)))
	107	#define CPP_WARN(text) _Pragma(CPP_STR(GCC warning text))
	108	#define CPP_NOTICE(text) _Pragma(CPP_STR(message text))
	109
	110	#else
	111	#define CPP_WARN(text)
ec40eaf9	112	#define CPP_NOTICE(text)
de1a880c DL	113	#endif
de1a880c DL	114
0d019561 DL	115	/* MAX / MIN are not commonly defined, but useful */
	116	/* note: glibc sys/param.h has #define MIN(a,b) (((a)<(b))?(a):(b)) */
	117	#ifdef MAX
	118	#undef MAX
	119	#endif
	120	#define MAX(a, b) \
	121	({ \
	122	typeof(a) _max_a = (a); \
	123	typeof(b) _max_b = (b); \
	124	_max_a > _max_b ? _max_a : _max_b; \
	125	})
	126	#ifdef MIN
	127	#undef MIN
	128	#endif
	129	#define MIN(a, b) \
	130	({ \
	131	typeof(a) _min_a = (a); \
	132	typeof(b) _min_b = (b); \
	133	_min_a < _min_b ? _min_a : _min_b; \
	134	})
	135
	136	#ifndef offsetof
	137	#ifdef __compiler_offsetof
	138	#define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE,MEMBER)
	139	#else
	140	#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
	141	#endif
	142	#endif
	143
	144	/* this variant of container_of() retains 'const' on pointers without needing
	145	* to be told to do so. The following will all work without warning:
	146	*
	147	* struct member *p;
	148	* const struct member *cp;
	149	*
	150	* const struct cont *x = container_of(cp, struct cont, member);
	151	* const struct cont *x = container_of(cp, const struct cont, member);
	152	* const struct cont *x = container_of(p, struct cont, member);
	153	* const struct cont *x = container_of(p, const struct cont, member);
	154	* struct cont *x = container_of(p, struct cont, member);
	155	*
	156	* but the following will generate warnings about stripping const:
	157	*
	158	* struct cont *x = container_of(cp, struct cont, member);
	159	* struct cont *x = container_of(cp, const struct cont, member);
	160	* struct cont *x = container_of(p, const struct cont, member);
	161	*/
	162	#ifdef container_of
	163	#undef container_of
	164	#endif
	165	#define container_of(ptr, type, member) \
	166	(__builtin_choose_expr( \
	167	__builtin_types_compatible_p(typeof(&((type *)0)->member), \
	168	typeof(ptr)) \
	169	\|\| __builtin_types_compatible_p(void *, typeof(ptr)), \
	170	({ \
	171	typeof(((type )0)->member) __mptr = (void *)(ptr); \
	172	(type )((char )__mptr - offsetof(type, member)); \
	173	}), \
	174	({ \
	175	typeof(((const type )0)->member) __mptr = (ptr); \
	176	(const type )((const char )__mptr - \
	177	offsetof(type, member)); \
	178	}) \
179	))
180
181	#define container_of_null(ptr, type, member) \
182	({ \
183	typeof(ptr) _tmp = (ptr); \
184	_tmp ? container_of(_tmp, type, member) : NULL; \
185	})
186
187	#define array_size(ar) (sizeof(ar) / sizeof(ar[0]))
188
5e244469 RW	189	#ifdef __cplusplus
	190	}
	191	#endif
	192
de1a880c	193	#endif /* _FRR_COMPILER_H */