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