2 * SPDX-License-Identifier: MIT
4 * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 #ifndef _LTTNG_UST_UTILS_H
8 #define _LTTNG_UST_UTILS_H
12 #include <urcu/compiler.h>
14 /* For lttng_ust_is_integer_type */
15 #if defined (__cplusplus)
16 #include <type_traits>
21 * lttng_ust_stringify - convert a literal value to a C string
23 #define __lttng_ust_stringify1(x) #x
24 #define lttng_ust_stringify(x) __lttng_ust_stringify1(x)
27 * lttng_ust_is_signed_type - check if type is signed
29 * Returns true if the type of @type is signed.
31 #if defined(__cplusplus)
32 #define lttng_ust_is_signed_type(type) (std::is_signed<type>::value)
34 #define lttng_ust_is_signed_type(type) ((type) -1 < (type) 1)
39 * lttng_ust_is_integer_type - check if type is an integer
41 * Returns true if the type of @type is an integer.
43 #if defined(__cplusplus)
44 #define lttng_ust_is_integer_type(type) (std::is_integral<type>::value)
46 #define lttng_ust_is_integer_type(type) \
47 (__builtin_types_compatible_p(type, _Bool) || \
48 __builtin_types_compatible_p(type, char) || \
49 __builtin_types_compatible_p(type, signed char) || \
50 __builtin_types_compatible_p(type, unsigned char) || \
51 __builtin_types_compatible_p(type, short) || \
52 __builtin_types_compatible_p(type, unsigned short) || \
53 __builtin_types_compatible_p(type, int) || \
54 __builtin_types_compatible_p(type, unsigned int) || \
55 __builtin_types_compatible_p(type, long) || \
56 __builtin_types_compatible_p(type, unsigned long) || \
57 __builtin_types_compatible_p(type, long long) || \
58 __builtin_types_compatible_p(type, unsigned long long))
62 * lttng_ust_is_pointer_type - check if type is a pointer
64 * Returns true if the type of @type is a pointer.
66 * Note: The C implementation of lttng_ust_is_pointer_type uses pointer
67 * arithmetic, which does not work on opaque pointer types.
69 #if defined(__cplusplus)
70 #define lttng_ust_is_pointer_type(type) (std::is_pointer<type>::value)
72 /* The difference between two pointers is an integer. */
73 #define lttng_ust_is_pointer_type(type) \
74 (lttng_ust_is_integer_type(typeof(((type)1 - (type)1))) && !lttng_ust_is_integer_type(type))
79 * lttng_ust_field_array_element_type_is_supported -
81 * Adds a compilation assertion that array and sequence fields declared by the
82 * user are of an integral or pointer type.
84 #define lttng_ust_field_array_element_type_is_supported(type, item) \
85 lttng_ust_static_assert(lttng_ust_is_integer_type(type) || lttng_ust_is_pointer_type(type), \
86 "Non-integer, non-pointer type `" #item "` not supported as element of LTTNG_UST_FIELD_ARRAY or LTTNG_UST_FIELD_SEQUENCE", \
87 Non_integer_type__##item##__not_supported_as_element_of_LTTNG_UST_FIELD_ARRAY_or_LTTNG_UST_FIELD_SEQUENCE)
91 * lttng_ust_runtime_bug_on - check condition at runtime
92 * @condition: the condition which should be false.
94 * If the condition is true, a BUG will be triggered at runtime.
96 #define lttng_ust_runtime_bug_on(condition) \
98 if (caa_unlikely(condition)) { \
100 "LTTng BUG in file %s, line %d.\n", \
101 __FILE__, __LINE__); \
102 exit(EXIT_FAILURE); \
108 * lttng_ust_build_bug_on - check condition at build
109 * @condition: the condition which should be false.
111 * If the condition is true, the compiler will generate a build error.
113 #define lttng_ust_build_bug_on(condition) \
114 ((void) sizeof(char[-!!(condition)]))
118 * lttng_ust_build_runtime_bug_on - check condition at build (if constant) or runtime
119 * @condition: the condition which should be false.
121 * If the condition is a constant and true, the compiler will generate a build
122 * error. If the condition is not constant, a BUG will be triggered at runtime
123 * if the condition is ever true. If the condition is constant and false, no
126 #define lttng_ust_build_runtime_bug_on(condition) \
128 if (__builtin_constant_p(condition)) \
129 lttng_ust_build_bug_on(condition); \
131 lttng_ust_runtime_bug_on(condition); \
136 * lttng_ust_offset_align - Calculate the offset needed to align an object on
137 * its natural alignment towards higher addresses.
138 * @align_drift: object offset from an "alignment"-aligned address.
139 * @alignment: natural object alignment. Must be non-zero, power of 2.
141 * Returns the offset that must be added to align towards higher
144 #define lttng_ust_offset_align(align_drift, alignment) \
146 lttng_ust_build_runtime_bug_on((alignment) == 0 \
147 || ((alignment) & ((alignment) - 1))); \
148 (((alignment) - (align_drift)) & ((alignment) - 1)); \
153 * lttng_ust_offset_align_floor - Calculate the offset needed to align an
154 * object on its natural alignment towards lower addresses.
155 * @align_drift: object offset from an "alignment"-aligned address.
156 * @alignment: natural object alignment. Must be non-zero, power of 2.
158 * Returns the offset that must be subtracted to align towards lower addresses.
160 #define lttng_ust_offset_align_floor(align_drift, alignment) \
162 lttng_ust_build_runtime_bug_on((alignment) == 0 \
163 || ((alignment) & ((alignment) - 1))); \
164 (((align_drift) - (alignment)) & ((alignment) - 1)); \
167 #endif /* _LTTNG_UST_UTILS_H */
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