[lttng-ust.git] / include / lttng / ust-compiler.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 * Copyright (C) 2011-2012 Paul Woegerer <paul_woegerer@mentor.com>
 */

#ifndef _LTTNG_UST_COMPILER_H
#define _LTTNG_UST_COMPILER_H

#include <assert.h>

#define lttng_ust_notrace __attribute__((no_instrument_function))

/*
 * Clang supports the no_sanitize variable attribute on global variables.
 * GCC only supports the no_sanitize_address function attribute, which is
 * not what we need.
 */
#if defined(__clang__)
# if __has_feature(address_sanitizer)
#  define __lttng_ust_variable_attribute_no_sanitize_address \
	__attribute__((no_sanitize("address")))
# else
#  define __lttng_ust_variable_attribute_no_sanitize_address
# endif
#else
#  define __lttng_ust_variable_attribute_no_sanitize_address
#endif

/*
 * g++ 4.8 and prior do not support C99 compound literals. Therefore,
 * force allocating those on the heap with these C++ compilers.
 */
#if defined (__cplusplus) && !defined (__clang__) && defined (__GNUC__) && \
	((__GNUC__ < 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 8)))
# ifndef LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
#  define LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
# endif
#endif

/*
 * Compound literals with static storage are needed by LTTng.
 * Compound literals are part of the C99 and C11 standards, but not
 * part of the C++ standards. However, those are supported by both g++ and
 * clang. In order to be strictly C++11 compliant, defining
 * LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header
 * allocates those on the heap in C++.
 *
 * Example use:
 * static struct mystruct *var = LTTNG_UST_COMPOUND_LITERAL(struct mystruct, { 1, 2, 3 });
 */
#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
#define LTTNG_UST_COMPOUND_LITERAL(type, ...)	new (type) __VA_ARGS__
#else
#define LTTNG_UST_COMPOUND_LITERAL(type, ...)	(type[]) { __VA_ARGS__ }
#endif

/*
 * Compile time assertion.
 * - predicate: boolean expression to evaluate,
 * - msg: string to print to the user on failure when `static_assert()` is
 *   supported,
 * - c_identifier_msg: message to be included in the typedef to emulate a
 *   static assertion. This parameter must be a valid C identifier as it will
 *   be used as a typedef name.
 */
#ifdef __cplusplus
#define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
	static_assert(predicate, msg)
#elif __STDC_VERSION__ >= 201112L
#define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
	_Static_assert(predicate, msg)
#else
/*
 * Evaluates the predicate and emit a compilation error on failure.
 *
 * If the predicate evaluates to true, this macro emits a typedef of an array
 * of size 0.
 *
 * If the predicate evaluates to false, this macro emits a typedef of an array
 * of negative size which is invalid in C and forces a compiler error. The msg
 * parameter is used in the tentative typedef so it is printed to the user.
 */
#define lttng_ust_static_assert(predicate, msg, c_identifier_msg)  \
    typedef char lttng_ust_static_assert_##c_identifier_msg[2*!!(predicate)-1]
#endif

/*
 * Wrap constructor and destructor functions to invoke them as functions with
 * the constructor/destructor GNU C attributes when building as C, or as the
 * constructor/destructor of a variable defined within an anonymous namespace
 * when building as C++.
 */
#ifdef __cplusplus
#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,        \
						 destructor_func, ...)          \
namespace lttng {                                                               \
namespace ust {                                                                 \
namespace details {                                                             \
class LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_,           \
				   name) {                                      \
public:                                                                         \
	LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_,         \
				     name)() __VA_ARGS__        \
	{                                                                       \
		constructor_func();                                             \
	}                                                                       \
	~LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_,        \
                                      name)() __VA_ARGS__       \
	{                                                                       \
		destructor_func();                                              \
	}                                                                       \
};                                                                              \
}                                                                               \
}                                                                               \
}                                                                               \
                                                                                \
namespace {                                                                     \
const lttng::ust::details::LTTNG_UST__TP_COMBINE_TOKENS(                        \
	lttng_ust_constructor_destructor_, name)                                \
		LTTNG_UST__TP_COMBINE_TOKENS(name, registration_instance);      \
}
#else /* __cplusplus */
#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,             \
						 destructor_func, ...)               \
	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
		__attribute__((constructor)) __VA_ARGS__;            \
	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	{                                                                            \
		constructor_func();                                                  \
	}                                                                            \
	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_destructor_, name)(void)  \
		__attribute__((destructor)) __VA_ARGS__;             \
	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_destructor_, name)(void)  \
	{                                                                            \
		destructor_func();                                                   \
	}
#endif

#endif /* _LTTNG_UST_COMPILER_H */
Commit	Line	Data
a8909ba5	1	/*
c0c0989a	2	* SPDX-License-Identifier: MIT
a8909ba5	3	*
c0c0989a MJ	4	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
c0c0989a MJ	5	* Copyright (C) 2011-2012 Paul Woegerer <paul_woegerer@mentor.com>
a8909ba5 PW	6	*/
a8909ba5 PW	7
c0c0989a MJ	8	#ifndef _LTTNG_UST_COMPILER_H
	9	#define _LTTNG_UST_COMPILER_H
	10
7f264068 FD	11	#include <assert.h>
7f264068 FD	12
a8909ba5 PW	13	#define lttng_ust_notrace __attribute__((no_instrument_function))
a8909ba5 PW	14
4f74bc5e MD	15	/*
	16	* Clang supports the no_sanitize variable attribute on global variables.
	17	* GCC only supports the no_sanitize_address function attribute, which is
	18	* not what we need.
	19	*/
	20	#if defined(__clang__)
	21	# if __has_feature(address_sanitizer)
	22	# define __lttng_ust_variable_attribute_no_sanitize_address \
	23	__attribute__((no_sanitize("address")))
	24	# else
	25	# define __lttng_ust_variable_attribute_no_sanitize_address
	26	# endif
	27	#else
	28	# define __lttng_ust_variable_attribute_no_sanitize_address
	29	#endif
	30
e1904921 MD	31	/*
	32	* g++ 4.8 and prior do not support C99 compound literals. Therefore,
	33	* force allocating those on the heap with these C++ compilers.
	34	*/
7850c5cc MJ	35	#if defined (__cplusplus) && !defined (__clang__) && defined (__GNUC__) && \
7850c5cc MJ	36	((__GNUC__ < 4) \|\| ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 8)))
439f90cf MD	37	# ifndef LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
439f90cf MD	38	# define LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
e1904921 MD	39	# endif
	40	#endif
	41
7edfc172 MD	42	/*
	43	* Compound literals with static storage are needed by LTTng.
	44	* Compound literals are part of the C99 and C11 standards, but not
	45	* part of the C++ standards. However, those are supported by both g++ and
	46	* clang. In order to be strictly C++11 compliant, defining
439f90cf	47	* LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header
7edfc172 MD	48	* allocates those on the heap in C++.
	49	*
	50	* Example use:
5defa774	51	* static struct mystruct *var = LTTNG_UST_COMPOUND_LITERAL(struct mystruct, { 1, 2, 3 });
7edfc172	52	*/
439f90cf	53	#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
5defa774	54	#define LTTNG_UST_COMPOUND_LITERAL(type, ...) new (type) __VA_ARGS__
7edfc172	55	#else
5defa774	56	#define LTTNG_UST_COMPOUND_LITERAL(type, ...) (type[]) { __VA_ARGS__ }
7edfc172 MD	57	#endif
7edfc172 MD	58
7f264068 FD	59	/*
	60	* Compile time assertion.
	61	* - predicate: boolean expression to evaluate,
	62	* - msg: string to print to the user on failure when `static_assert()` is
	63	* supported,
	64	* - c_identifier_msg: message to be included in the typedef to emulate a
	65	* static assertion. This parameter must be a valid C identifier as it will
	66	* be used as a typedef name.
	67	*/
89350fda	68	#ifdef __cplusplus
3a98c813	69	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
7f264068	70	static_assert(predicate, msg)
89350fda MD	71	#elif __STDC_VERSION__ >= 201112L
	72	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
	73	_Static_assert(predicate, msg)
7f264068 FD	74	#else
	75	/*
	76	* Evaluates the predicate and emit a compilation error on failure.
	77	*
	78	* If the predicate evaluates to true, this macro emits a typedef of an array
	79	* of size 0.
	80	*
	81	* If the predicate evaluates to false, this macro emits a typedef of an array
	82	* of negative size which is invalid in C and forces a compiler error. The msg
	83	* parameter is used in the tentative typedef so it is printed to the user.
	84	*/
3a98c813	85	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
b4c54822	86	typedef char lttng_ust_static_assert_##c_identifier_msg[2*!!(predicate)-1]
7f264068 FD	87	#endif
7f264068 FD	88
05bfa3dc JG	89	/*
	90	* Wrap constructor and destructor functions to invoke them as functions with
	91	* the constructor/destructor GNU C attributes when building as C, or as the
	92	* constructor/destructor of a variable defined within an anonymous namespace
	93	* when building as C++.
	94	*/
	95	#ifdef __cplusplus
	96	#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func, \
	97	destructor_func, ...) \
	98	namespace lttng { \
	99	namespace ust { \
	100	namespace details { \
	101	class LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_, \
	102	name) { \
	103	public: \
	104	LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_, \
	105	name)() __VA_ARGS__ \
	106	{ \
	107	constructor_func(); \
	108	} \
	109	~LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_destructor_, \
	110	name)() __VA_ARGS__ \
	111	{ \
	112	destructor_func(); \
	113	} \
	114	}; \
	115	} \
	116	} \
	117	} \
	118	\
	119	namespace { \
	120	const lttng::ust::details::LTTNG_UST__TP_COMBINE_TOKENS( \
	121	lttng_ust_constructor_destructor_, name) \
	122	LTTNG_UST__TP_COMBINE_TOKENS(name, registration_instance); \
	123	}
	124	#else /* __cplusplus */
	125	#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func, \
	126	destructor_func, ...) \
	127	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	128	__attribute__((constructor)) __VA_ARGS__; \
	129	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	130	{ \
	131	constructor_func(); \
	132	} \
	133	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
	134	__attribute__((destructor)) __VA_ARGS__; \
	135	static void LTTNG_UST__TP_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
	136	{ \
	137	destructor_func(); \
	138	}
	139	#endif
	140
a8909ba5	141	#endif /* _LTTNG_UST_COMPILER_H */