[userspace-rcu.git] / include / urcu / compiler.h

#ifndef _URCU_COMPILER_H
#define _URCU_COMPILER_H

/*
 * compiler.h
 *
 * Compiler definitions.
 *
 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 */

#include <stddef.h>	/* for offsetof */

#if defined __cplusplus
# include <type_traits>	/* for std::remove_cv */
#endif

#define caa_likely(x)	__builtin_expect(!!(x), 1)
#define caa_unlikely(x)	__builtin_expect(!!(x), 0)

#define	cmm_barrier()	__asm__ __volatile__ ("" : : : "memory")

/*
 * Instruct the compiler to perform only a single access to a variable
 * (prohibits merging and refetching). The compiler is also forbidden to reorder
 * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of
 * particular ordering. Compiler ordering can be ensured, for example, by
 * putting two CMM_ACCESS_ONCE() in separate C statements.
 *
 * This macro does absolutely -nothing- to prevent the CPU from reordering,
 * merging, or refetching absolutely anything at any time.  Its main intended
 * use is to mediate communication between process-level code and irq/NMI
 * handlers, all running on the same CPU.
 */
#define CMM_ACCESS_ONCE(x)	(*(__volatile__  __typeof__(x) *)&(x))

#ifndef caa_max
#define caa_max(a,b) ((a)>(b)?(a):(b))
#endif

#ifndef caa_min
#define caa_min(a,b) ((a)<(b)?(a):(b))
#endif

#if defined(__SIZEOF_LONG__)
#define CAA_BITS_PER_LONG	(__SIZEOF_LONG__ * 8)
#elif defined(_LP64)
#define CAA_BITS_PER_LONG	64
#else
#define CAA_BITS_PER_LONG	32
#endif

/*
 * caa_container_of - Get the address of an object containing a field.
 *
 * @ptr: pointer to the field.
 * @type: type of the object.
 * @member: name of the field within the object.
 */
#define caa_container_of(ptr, type, member)				\
	__extension__							\
	({								\
		const __typeof__(((type *) NULL)->member) * __ptr = (ptr); \
		(type *)((char *)__ptr - offsetof(type, member));	\
	})

#define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
#define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))

/*
 * __rcu is an annotation that documents RCU pointer accesses that need
 * to be protected by a read-side critical section. Eventually, a static
 * checker will be able to use this annotation to detect incorrect RCU
 * usage.
 */
#define __rcu

#ifdef __cplusplus
#define URCU_FORCE_CAST(_type, arg)	(reinterpret_cast<std::remove_cv<_type>::type>(arg))
#else
#define URCU_FORCE_CAST(type, arg)	((type) (arg))
#endif

#define caa_is_signed_type(type)	((type) -1 < (type) 0)

/*
 * Cast to unsigned long, sign-extending if @v is signed.
 * Note: casting to a larger type or to same type size keeps the sign of
 * the expression being cast (see C99 6.3.1.3).
 */
#define caa_cast_long_keep_sign(v)	((unsigned long) (v))

#if defined (__GNUC__) \
	&& ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)	\
		|| __GNUC__ >= 5)
#define CDS_DEPRECATED(msg)	\
	__attribute__((deprecated(msg)))
#else
#define CDS_DEPRECATED(msg)	\
	__attribute__((deprecated))
#endif

#define CAA_ARRAY_SIZE(x)	(sizeof(x) / sizeof((x)[0]))

/*
 * URCU_GCC_VERSION is used to blacklist specific GCC versions with known
 * bugs, clang also defines these macros to an equivalent GCC version it
 * claims to support, so exclude it.
 */
#if defined(__GNUC__) && !defined(__clang__)
# define URCU_GCC_VERSION	(__GNUC__ * 10000 \
				+ __GNUC_MINOR__ * 100 \
				+ __GNUC_PATCHLEVEL__)
#endif

#endif /* _URCU_COMPILER_H */
Commit	Line	Data
	1	#ifndef _URCU_COMPILER_H
	2	#define _URCU_COMPILER_H
	3
	4	/*
	5	* compiler.h
	6	*
	7	* Compiler definitions.
	8	*
	9	* Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	10	*
	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:
	17	*
	18	* The above copyright notice and this permission notice shall be included in
	19	* all copies or substantial portions of the Software.
	20	*/
	21
	22	#include <stddef.h> /* for offsetof */
	23
	24	#if defined __cplusplus
	25	# include <type_traits> /* for std::remove_cv */
	26	#endif
	27
	28	#define caa_likely(x) __builtin_expect(!!(x), 1)
	29	#define caa_unlikely(x) __builtin_expect(!!(x), 0)
	30
	31	#define cmm_barrier() __asm__ __volatile__ ("" : : : "memory")
	32
	33	/*
	34	* Instruct the compiler to perform only a single access to a variable
	35	* (prohibits merging and refetching). The compiler is also forbidden to reorder
	36	* successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of
	37	* particular ordering. Compiler ordering can be ensured, for example, by
	38	* putting two CMM_ACCESS_ONCE() in separate C statements.
	39	*
	40	* This macro does absolutely -nothing- to prevent the CPU from reordering,
	41	* merging, or refetching absolutely anything at any time. Its main intended
	42	* use is to mediate communication between process-level code and irq/NMI
	43	* handlers, all running on the same CPU.
	44	*/
	45	#define CMM_ACCESS_ONCE(x) ((__volatile__ __typeof__(x) )&(x))
	46
	47	#ifndef caa_max
	48	#define caa_max(a,b) ((a)>(b)?(a):(b))
	49	#endif
	50
	51	#ifndef caa_min
	52	#define caa_min(a,b) ((a)<(b)?(a):(b))
	53	#endif
	54
	55	#if defined(__SIZEOF_LONG__)
	56	#define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8)
	57	#elif defined(_LP64)
	58	#define CAA_BITS_PER_LONG 64
	59	#else
	60	#define CAA_BITS_PER_LONG 32
	61	#endif
	62
	63	/*
	64	* caa_container_of - Get the address of an object containing a field.
	65	*
	66	* @ptr: pointer to the field.
	67	* @type: type of the object.
	68	* @member: name of the field within the object.
	69	*/
	70	#define caa_container_of(ptr, type, member) \
	71	__extension__ \
	72	({ \
	73	const __typeof__(((type ) NULL)->member) __ptr = (ptr); \
	74	(type )((char )__ptr - offsetof(type, member)); \
	75	})
	76
	77	#define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
	78	#define CAA_BUILD_BUG_ON(cond) ((void)CAA_BUILD_BUG_ON_ZERO(cond))
	79
	80	/*
	81	* __rcu is an annotation that documents RCU pointer accesses that need
	82	* to be protected by a read-side critical section. Eventually, a static
	83	* checker will be able to use this annotation to detect incorrect RCU
	84	* usage.
	85	*/
	86	#define __rcu
	87
	88	#ifdef __cplusplus
	89	#define URCU_FORCE_CAST(_type, arg) (reinterpret_cast<std::remove_cv<_type>::type>(arg))
	90	#else
	91	#define URCU_FORCE_CAST(type, arg) ((type) (arg))
	92	#endif
	93
	94	#define caa_is_signed_type(type) ((type) -1 < (type) 0)
	95
	96	/*
	97	* Cast to unsigned long, sign-extending if @v is signed.
	98	* Note: casting to a larger type or to same type size keeps the sign of
	99	* the expression being cast (see C99 6.3.1.3).
	100	*/
	101	#define caa_cast_long_keep_sign(v) ((unsigned long) (v))
	102
	103	#if defined (__GNUC__) \
	104	&& ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5) \
	105	\|\| __GNUC__ >= 5)
	106	#define CDS_DEPRECATED(msg) \
	107	__attribute__((deprecated(msg)))
	108	#else
	109	#define CDS_DEPRECATED(msg) \
	110	__attribute__((deprecated))
	111	#endif
	112
	113	#define CAA_ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
	114
	115	/*
	116	* URCU_GCC_VERSION is used to blacklist specific GCC versions with known
	117	* bugs, clang also defines these macros to an equivalent GCC version it
	118	* claims to support, so exclude it.
	119	*/
	120	#if defined(__GNUC__) && !defined(__clang__)
	121	# define URCU_GCC_VERSION (__GNUC__ * 10000 \
	122	+ __GNUC_MINOR__ * 100 \
	123	+ __GNUC_PATCHLEVEL__)
	124	#endif
	125
	126	#endif /* _URCU_COMPILER_H */