[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>

/*
 * By default, LTTng-UST uses the priority 150 for the tracepoint and probe
 * provider constructors to trace tracepoints located within
 * constructors/destructors with a higher priority value within the same
 * module. This priority can be overridden by the application.
 */
#ifndef LTTNG_UST_CONSTRUCTOR_PRIO
#define LTTNG_UST_CONSTRUCTOR_PRIO	150
#endif

#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 defined(__STDC_VERSION__) && (__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

/* Combine two tokens. */
#define LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)			\
		_tokena##_tokenb
#define LTTNG_UST_COMPILER_COMBINE_TOKENS(_tokena, _tokenb)			\
		LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)
/*
 * Wrap constructor and destructor functions to invoke them as functions with
 * the constructor/destructor GNU C attributes, which ensures that those
 * constructors/destructors are ordered before/after C++
 * constructors/destructors.
 *
 * Wrap constructor and destructor functions as the constructor/destructor of a
 * variable defined within an anonymous namespace when building as C++ with
 * LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP defined. With this option,
 * there are no guarantees that the events in C++ constructors/destructors will
 * be traced.
 */
#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,	\
						 destructor_func, ...)		\
namespace lttng {								\
namespace ust {									\
namespace details {								\
class LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_,      \
				   name) {					\
public:										\
	LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
	~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
};										\
LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
{										\
	constructor_func();							\
}										\
LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
{										\
	destructor_func();							\
}										\
}										\
}										\
}										\
										\
namespace {									\
const lttng::ust::details::LTTNG_UST_COMPILER_COMBINE_TOKENS(			\
	lttng_ust_constructor_destructor_, name)				\
		LTTNG_UST_COMPILER_COMBINE_TOKENS(name, registration_instance); \
}
#else
#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func,	\
						 destructor_func, ...)		\
	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
		__attribute__((constructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	{									\
		constructor_func();						\
	}									\
	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
		__attribute__((destructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
	{									\
		destructor_func();						\
	}
#endif

#endif /* _LTTNG_UST_COMPILER_H */
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: MIT
	3	*
	4	* Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	* Copyright (C) 2011-2012 Paul Woegerer <paul_woegerer@mentor.com>
	6	*/
	7
	8	#ifndef _LTTNG_UST_COMPILER_H
	9	#define _LTTNG_UST_COMPILER_H
	10
	11	#include <assert.h>
	12
	13	/*
	14	* By default, LTTng-UST uses the priority 150 for the tracepoint and probe
	15	* provider constructors to trace tracepoints located within
	16	* constructors/destructors with a higher priority value within the same
	17	* module. This priority can be overridden by the application.
	18	*/
	19	#ifndef LTTNG_UST_CONSTRUCTOR_PRIO
	20	#define LTTNG_UST_CONSTRUCTOR_PRIO 150
	21	#endif
	22
	23	#define lttng_ust_notrace __attribute__((no_instrument_function))
	24
	25	/*
	26	* Clang supports the no_sanitize variable attribute on global variables.
	27	* GCC only supports the no_sanitize_address function attribute, which is
	28	* not what we need.
	29	*/
	30	#if defined(__clang__)
	31	# if __has_feature(address_sanitizer)
	32	# define __lttng_ust_variable_attribute_no_sanitize_address \
	33	__attribute__((no_sanitize("address")))
	34	# else
	35	# define __lttng_ust_variable_attribute_no_sanitize_address
	36	# endif
	37	#else
	38	# define __lttng_ust_variable_attribute_no_sanitize_address
	39	#endif
	40
	41	/*
	42	* g++ 4.8 and prior do not support C99 compound literals. Therefore,
	43	* force allocating those on the heap with these C++ compilers.
	44	*/
	45	#if defined (__cplusplus) && !defined (__clang__) && defined (__GNUC__) && \
	46	((__GNUC__ < 4) \|\| ((__GNUC__ == 4) && (__GNUC_MINOR__ <= 8)))
	47	# ifndef LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
	48	# define LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP
	49	# endif
	50	#endif
	51
	52	/*
	53	* Compound literals with static storage are needed by LTTng.
	54	* Compound literals are part of the C99 and C11 standards, but not
	55	* part of the C++ standards. However, those are supported by both g++ and
	56	* clang. In order to be strictly C++11 compliant, defining
	57	* LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP before including this header
	58	* allocates those on the heap in C++.
	59	*
	60	* Example use:
	61	* static struct mystruct *var = LTTNG_UST_COMPOUND_LITERAL(struct mystruct, { 1, 2, 3 });
	62	*/
	63	#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
	64	#define LTTNG_UST_COMPOUND_LITERAL(type, ...) new (type) __VA_ARGS__
	65	#else
	66	#define LTTNG_UST_COMPOUND_LITERAL(type, ...) (type[]) { __VA_ARGS__ }
	67	#endif
	68
	69	/*
	70	* Compile time assertion.
	71	* - predicate: boolean expression to evaluate,
	72	* - msg: string to print to the user on failure when `static_assert()` is
	73	* supported,
	74	* - c_identifier_msg: message to be included in the typedef to emulate a
	75	* static assertion. This parameter must be a valid C identifier as it will
	76	* be used as a typedef name.
	77	*/
	78	#ifdef __cplusplus
	79	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
	80	static_assert(predicate, msg)
	81	#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
	82	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
	83	_Static_assert(predicate, msg)
	84	#else
	85	/*
	86	* Evaluates the predicate and emit a compilation error on failure.
	87	*
	88	* If the predicate evaluates to true, this macro emits a typedef of an array
	89	* of size 0.
	90	*
	91	* If the predicate evaluates to false, this macro emits a typedef of an array
	92	* of negative size which is invalid in C and forces a compiler error. The msg
	93	* parameter is used in the tentative typedef so it is printed to the user.
	94	*/
	95	#define lttng_ust_static_assert(predicate, msg, c_identifier_msg) \
	96	typedef char lttng_ust_static_assert_##c_identifier_msg[2*!!(predicate)-1]
	97	#endif
	98
	99	/* Combine two tokens. */
	100	#define LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb) \
	101	_tokena##_tokenb
	102	#define LTTNG_UST_COMPILER_COMBINE_TOKENS(_tokena, _tokenb) \
	103	LTTNG_UST_COMPILER__COMBINE_TOKENS(_tokena, _tokenb)
	104	/*
	105	* Wrap constructor and destructor functions to invoke them as functions with
	106	* the constructor/destructor GNU C attributes, which ensures that those
	107	* constructors/destructors are ordered before/after C++
	108	* constructors/destructors.
	109	*
	110	* Wrap constructor and destructor functions as the constructor/destructor of a
	111	* variable defined within an anonymous namespace when building as C++ with
	112	* LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP defined. With this option,
	113	* there are no guarantees that the events in C++ constructors/destructors will
	114	* be traced.
	115	*/
	116	#if defined (__cplusplus) && defined (LTTNG_UST_ALLOCATE_COMPOUND_LITERAL_ON_HEAP)
	117	#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func, \
	118	destructor_func, ...) \
	119	namespace lttng { \
	120	namespace ust { \
	121	namespace details { \
	122	class LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, \
	123	name) { \
	124	public: \
	125	LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
	126	~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() __VA_ARGS__; \
	127	}; \
	128	LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
	129	{ \
	130	constructor_func(); \
	131	} \
	132	LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)::~LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_destructor_, name)() \
	133	{ \
	134	destructor_func(); \
	135	} \
	136	} \
	137	} \
	138	} \
	139	\
	140	namespace { \
	141	const lttng::ust::details::LTTNG_UST_COMPILER_COMBINE_TOKENS( \
	142	lttng_ust_constructor_destructor_, name) \
	143	LTTNG_UST_COMPILER_COMBINE_TOKENS(name, registration_instance); \
	144	}
	145	#else
	146	#define LTTNG_UST_DECLARE_CONSTRUCTOR_DESTRUCTOR(name, constructor_func, \
	147	destructor_func, ...) \
	148	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	149	__attribute__((constructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
	150	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_constructor_, name)(void) \
	151	{ \
	152	constructor_func(); \
	153	} \
	154	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
	155	__attribute__((destructor(LTTNG_UST_CONSTRUCTOR_PRIO))) __VA_ARGS__; \
	156	static void LTTNG_UST_COMPILER_COMBINE_TOKENS(lttng_ust_destructor_, name)(void) \
	157	{ \
	158	destructor_func(); \
	159	}
	160	#endif
	161
	162	#endif /* _LTTNG_UST_COMPILER_H */