| 1 | // SPDX-FileCopyrightText: 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 2 | // |
| 3 | // SPDX-License-Identifier: MIT |
| 4 | |
| 5 | #ifndef _LTTNG_UST_UTILS_H |
| 6 | #define _LTTNG_UST_UTILS_H |
| 7 | |
| 8 | #include <stdio.h> |
| 9 | #include <stdlib.h> |
| 10 | #include <urcu/compiler.h> |
| 11 | |
| 12 | /* For lttng_ust_is_integer_type */ |
| 13 | #if defined (__cplusplus) |
| 14 | #include <type_traits> |
| 15 | #endif |
| 16 | |
| 17 | |
| 18 | /** |
| 19 | * lttng_ust_stringify - convert a literal value to a C string |
| 20 | */ |
| 21 | #define __lttng_ust_stringify1(x) #x |
| 22 | #define lttng_ust_stringify(x) __lttng_ust_stringify1(x) |
| 23 | |
| 24 | /** |
| 25 | * lttng_ust_is_signed_type - check if type is signed |
| 26 | * |
| 27 | * Returns true if the type of @type is signed. |
| 28 | */ |
| 29 | #if defined(__cplusplus) |
| 30 | #define lttng_ust_is_signed_type(type) (std::is_signed<type>::value) |
| 31 | #else |
| 32 | #define lttng_ust_is_signed_type(type) ((type) -1 < (type) 1) |
| 33 | #endif |
| 34 | |
| 35 | |
| 36 | /** |
| 37 | * lttng_ust_is_integer_type - check if type is an integer |
| 38 | * |
| 39 | * Returns true if the type of @type is an integer. |
| 40 | */ |
| 41 | #if defined(__cplusplus) |
| 42 | #define lttng_ust_is_integer_type(type) (std::is_integral<type>::value) |
| 43 | #else |
| 44 | #define lttng_ust_is_integer_type(type) \ |
| 45 | (__builtin_types_compatible_p(type, _Bool) || \ |
| 46 | __builtin_types_compatible_p(type, char) || \ |
| 47 | __builtin_types_compatible_p(type, signed char) || \ |
| 48 | __builtin_types_compatible_p(type, unsigned char) || \ |
| 49 | __builtin_types_compatible_p(type, short) || \ |
| 50 | __builtin_types_compatible_p(type, unsigned short) || \ |
| 51 | __builtin_types_compatible_p(type, int) || \ |
| 52 | __builtin_types_compatible_p(type, unsigned int) || \ |
| 53 | __builtin_types_compatible_p(type, long) || \ |
| 54 | __builtin_types_compatible_p(type, unsigned long) || \ |
| 55 | __builtin_types_compatible_p(type, long long) || \ |
| 56 | __builtin_types_compatible_p(type, unsigned long long)) |
| 57 | #endif |
| 58 | |
| 59 | /** |
| 60 | * lttng_ust_is_pointer_type - check if type is a pointer |
| 61 | * |
| 62 | * Returns true if the type of @type is a pointer. |
| 63 | * |
| 64 | * Note: The C implementation of lttng_ust_is_pointer_type uses pointer |
| 65 | * arithmetic, which does not work on opaque pointer types. |
| 66 | */ |
| 67 | #if defined(__cplusplus) |
| 68 | #define lttng_ust_is_pointer_type(type) (std::is_pointer<type>::value) |
| 69 | #else |
| 70 | /* The difference between two pointers is an integer. */ |
| 71 | #define lttng_ust_is_pointer_type(type) \ |
| 72 | (lttng_ust_is_integer_type(typeof(((type)1 - (type)1))) && !lttng_ust_is_integer_type(type)) |
| 73 | #endif |
| 74 | |
| 75 | |
| 76 | /** |
| 77 | * lttng_ust_field_array_element_type_is_supported - |
| 78 | * |
| 79 | * Adds a compilation assertion that array and sequence fields declared by the |
| 80 | * user are of an integral or pointer type. |
| 81 | */ |
| 82 | #define lttng_ust_field_array_element_type_is_supported(type, item) \ |
| 83 | lttng_ust_static_assert(lttng_ust_is_integer_type(type) || lttng_ust_is_pointer_type(type), \ |
| 84 | "Non-integer, non-pointer type `" #item "` not supported as element of LTTNG_UST_FIELD_ARRAY or LTTNG_UST_FIELD_SEQUENCE", \ |
| 85 | Non_integer_type__##item##__not_supported_as_element_of_LTTNG_UST_FIELD_ARRAY_or_LTTNG_UST_FIELD_SEQUENCE) |
| 86 | |
| 87 | |
| 88 | /** |
| 89 | * lttng_ust_runtime_bug_on - check condition at runtime |
| 90 | * @condition: the condition which should be false. |
| 91 | * |
| 92 | * If the condition is true, a BUG will be triggered at runtime. |
| 93 | */ |
| 94 | #define lttng_ust_runtime_bug_on(condition) \ |
| 95 | do { \ |
| 96 | if (caa_unlikely(condition)) { \ |
| 97 | fprintf(stderr, \ |
| 98 | "LTTng BUG in file %s, line %d.\n", \ |
| 99 | __FILE__, __LINE__); \ |
| 100 | exit(EXIT_FAILURE); \ |
| 101 | } \ |
| 102 | } while (0) |
| 103 | |
| 104 | |
| 105 | /** |
| 106 | * lttng_ust_build_bug_on - check condition at build |
| 107 | * @condition: the condition which should be false. |
| 108 | * |
| 109 | * If the condition is true, the compiler will generate a build error. |
| 110 | */ |
| 111 | #define lttng_ust_build_bug_on(condition) \ |
| 112 | ((void) sizeof(char[-!!(condition)])) |
| 113 | |
| 114 | |
| 115 | /** |
| 116 | * lttng_ust_build_runtime_bug_on - check condition at build (if constant) or runtime |
| 117 | * @condition: the condition which should be false. |
| 118 | * |
| 119 | * If the condition is a constant and true, the compiler will generate a build |
| 120 | * error. If the condition is not constant, a BUG will be triggered at runtime |
| 121 | * if the condition is ever true. If the condition is constant and false, no |
| 122 | * code is emitted. |
| 123 | */ |
| 124 | #define lttng_ust_build_runtime_bug_on(condition) \ |
| 125 | do { \ |
| 126 | if (__builtin_constant_p(condition)) \ |
| 127 | lttng_ust_build_bug_on(condition); \ |
| 128 | else \ |
| 129 | lttng_ust_runtime_bug_on(condition); \ |
| 130 | } while (0) |
| 131 | |
| 132 | |
| 133 | /** |
| 134 | * lttng_ust_offset_align - Calculate the offset needed to align an object on |
| 135 | * its natural alignment towards higher addresses. |
| 136 | * @align_drift: object offset from an "alignment"-aligned address. |
| 137 | * @alignment: natural object alignment. Must be non-zero, power of 2. |
| 138 | * |
| 139 | * Returns the offset that must be added to align towards higher |
| 140 | * addresses. |
| 141 | */ |
| 142 | #define lttng_ust_offset_align(align_drift, alignment) \ |
| 143 | ({ \ |
| 144 | lttng_ust_build_runtime_bug_on((alignment) == 0 \ |
| 145 | || ((alignment) & ((alignment) - 1))); \ |
| 146 | (((alignment) - (align_drift)) & ((alignment) - 1)); \ |
| 147 | }) |
| 148 | |
| 149 | |
| 150 | /** |
| 151 | * lttng_ust_offset_align_floor - Calculate the offset needed to align an |
| 152 | * object on its natural alignment towards lower addresses. |
| 153 | * @align_drift: object offset from an "alignment"-aligned address. |
| 154 | * @alignment: natural object alignment. Must be non-zero, power of 2. |
| 155 | * |
| 156 | * Returns the offset that must be subtracted to align towards lower addresses. |
| 157 | */ |
| 158 | #define lttng_ust_offset_align_floor(align_drift, alignment) \ |
| 159 | ({ \ |
| 160 | lttng_ust_build_runtime_bug_on((alignment) == 0 \ |
| 161 | || ((alignment) & ((alignment) - 1))); \ |
| 162 | (((align_drift) - (alignment)) & ((alignment) - 1)); \ |
| 163 | }) |
| 164 | |
| 165 | #endif /* _LTTNG_UST_UTILS_H */ |