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Diffstat (limited to 'gl/attribute.h')
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| 1 | /* ATTRIBUTE_* macros for using attributes in GCC and similar compilers | ||
| 2 | |||
| 3 | Copyright 2020-2023 Free Software Foundation, Inc. | ||
| 4 | |||
| 5 | This file is free software: you can redistribute it and/or modify | ||
| 6 | it under the terms of the GNU Lesser General Public License as | ||
| 7 | published by the Free Software Foundation; either version 2.1 of the | ||
| 8 | License, or (at your option) any later version. | ||
| 9 | |||
| 10 | This file is distributed in the hope that it will be useful, | ||
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| 13 | GNU Lesser General Public License for more details. | ||
| 14 | |||
| 15 | You should have received a copy of the GNU Lesser General Public License | ||
| 16 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ | ||
| 17 | |||
| 18 | /* Written by Paul Eggert. */ | ||
| 19 | |||
| 20 | /* Provide public ATTRIBUTE_* names for the private _GL_ATTRIBUTE_* | ||
| 21 | macros used within Gnulib. */ | ||
| 22 | |||
| 23 | /* These attributes can be placed in two ways: | ||
| 24 | - At the start of a declaration (i.e. even before storage-class | ||
| 25 | specifiers!); then they apply to all entities that are declared | ||
| 26 | by the declaration. | ||
| 27 | - Immediately after the name of an entity being declared by the | ||
| 28 | declaration; then they apply to that entity only. */ | ||
| 29 | |||
| 30 | #ifndef _GL_ATTRIBUTE_H | ||
| 31 | #define _GL_ATTRIBUTE_H | ||
| 32 | |||
| 33 | |||
| 34 | /* This file defines two types of attributes: | ||
| 35 | * C23 standard attributes. These have macro names that do not begin with | ||
| 36 | 'ATTRIBUTE_'. | ||
| 37 | * Selected GCC attributes; see: | ||
| 38 | https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html | ||
| 39 | https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html | ||
| 40 | https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html | ||
| 41 | These names begin with 'ATTRIBUTE_' to avoid name clashes. */ | ||
| 42 | |||
| 43 | |||
| 44 | /* =============== Attributes for specific kinds of functions =============== */ | ||
| 45 | |||
| 46 | /* Attributes for functions that should not be used. */ | ||
| 47 | |||
| 48 | /* Warn if the entity is used. */ | ||
| 49 | /* Applies to: | ||
| 50 | - function, variable, | ||
| 51 | - struct, union, struct/union member, | ||
| 52 | - enumeration, enumeration item, | ||
| 53 | - typedef, | ||
| 54 | in C++ also: namespace, class, template specialization. */ | ||
| 55 | #define DEPRECATED _GL_ATTRIBUTE_DEPRECATED | ||
| 56 | |||
| 57 | /* If a function call is not optimized way, warn with MSG. */ | ||
| 58 | /* Applies to: functions. */ | ||
| 59 | #define ATTRIBUTE_WARNING(msg) _GL_ATTRIBUTE_WARNING (msg) | ||
| 60 | |||
| 61 | /* If a function call is not optimized way, report an error with MSG. */ | ||
| 62 | /* Applies to: functions. */ | ||
| 63 | #define ATTRIBUTE_ERROR(msg) _GL_ATTRIBUTE_ERROR (msg) | ||
| 64 | |||
| 65 | |||
| 66 | /* Attributes for memory-allocating functions. */ | ||
| 67 | |||
| 68 | /* The function returns a pointer to freshly allocated memory. */ | ||
| 69 | /* Applies to: functions. */ | ||
| 70 | #define ATTRIBUTE_MALLOC _GL_ATTRIBUTE_MALLOC | ||
| 71 | |||
| 72 | /* ATTRIBUTE_ALLOC_SIZE ((N)) - The Nth argument of the function | ||
| 73 | is the size of the returned memory block. | ||
| 74 | ATTRIBUTE_ALLOC_SIZE ((M, N)) - Multiply the Mth and Nth arguments | ||
| 75 | to determine the size of the returned memory block. */ | ||
| 76 | /* Applies to: function, pointer to function, function types. */ | ||
| 77 | #define ATTRIBUTE_ALLOC_SIZE(args) _GL_ATTRIBUTE_ALLOC_SIZE (args) | ||
| 78 | |||
| 79 | /* ATTRIBUTE_DEALLOC (F, I) declares that the function returns pointers | ||
| 80 | that can be freed by passing them as the Ith argument to the | ||
| 81 | function F. | ||
| 82 | ATTRIBUTE_DEALLOC_FREE declares that the function returns pointers that | ||
| 83 | can be freed via 'free'; it can be used only after declaring 'free'. */ | ||
| 84 | /* Applies to: functions. Cannot be used on inline functions. */ | ||
| 85 | #define ATTRIBUTE_DEALLOC(f, i) _GL_ATTRIBUTE_DEALLOC(f, i) | ||
| 86 | #define ATTRIBUTE_DEALLOC_FREE _GL_ATTRIBUTE_DEALLOC_FREE | ||
| 87 | |||
| 88 | /* Attributes for variadic functions. */ | ||
| 89 | |||
| 90 | /* The variadic function expects a trailing NULL argument. | ||
| 91 | ATTRIBUTE_SENTINEL () - The last argument is NULL (requires C99). | ||
| 92 | ATTRIBUTE_SENTINEL ((N)) - The (N+1)st argument from the end is NULL. */ | ||
| 93 | /* Applies to: functions. */ | ||
| 94 | #define ATTRIBUTE_SENTINEL(pos) _GL_ATTRIBUTE_SENTINEL (pos) | ||
| 95 | |||
| 96 | |||
| 97 | /* ================== Attributes for compiler diagnostics ================== */ | ||
| 98 | |||
| 99 | /* Attributes that help the compiler diagnose programmer mistakes. | ||
| 100 | Some of them may also help for some compiler optimizations. */ | ||
| 101 | |||
| 102 | /* ATTRIBUTE_FORMAT ((ARCHETYPE, STRING-INDEX, FIRST-TO-CHECK)) - | ||
| 103 | The STRING-INDEXth function argument is a format string of style | ||
| 104 | ARCHETYPE, which is one of: | ||
| 105 | printf, gnu_printf | ||
| 106 | scanf, gnu_scanf, | ||
| 107 | strftime, gnu_strftime, | ||
| 108 | strfmon, | ||
| 109 | or the same thing prefixed and suffixed with '__'. | ||
| 110 | If FIRST-TO-CHECK is not 0, arguments starting at FIRST-TO_CHECK | ||
| 111 | are suitable for the format string. */ | ||
| 112 | /* Applies to: functions. */ | ||
| 113 | #define ATTRIBUTE_FORMAT(spec) _GL_ATTRIBUTE_FORMAT (spec) | ||
| 114 | |||
| 115 | /* ATTRIBUTE_NONNULL ((N1, N2,...)) - Arguments N1, N2,... must not be NULL. | ||
| 116 | ATTRIBUTE_NONNULL () - All pointer arguments must not be null. */ | ||
| 117 | /* Applies to: functions. */ | ||
| 118 | #define ATTRIBUTE_NONNULL(args) _GL_ATTRIBUTE_NONNULL (args) | ||
| 119 | |||
| 120 | /* The function's return value is a non-NULL pointer. */ | ||
| 121 | /* Applies to: functions. */ | ||
| 122 | #define ATTRIBUTE_RETURNS_NONNULL _GL_ATTRIBUTE_RETURNS_NONNULL | ||
| 123 | |||
| 124 | /* Warn if the caller does not use the return value, | ||
| 125 | unless the caller uses something like ignore_value. */ | ||
| 126 | /* Applies to: function, enumeration, class. */ | ||
| 127 | #define NODISCARD _GL_ATTRIBUTE_NODISCARD | ||
| 128 | |||
| 129 | |||
| 130 | /* Attributes that disable false alarms when the compiler diagnoses | ||
| 131 | programmer "mistakes". */ | ||
| 132 | |||
| 133 | /* Do not warn if the entity is not used. */ | ||
| 134 | /* Applies to: | ||
| 135 | - function, variable, | ||
| 136 | - struct, union, struct/union member, | ||
| 137 | - enumeration, enumeration item, | ||
| 138 | - typedef, | ||
| 139 | in C++ also: class. */ | ||
| 140 | #define MAYBE_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED | ||
| 141 | |||
| 142 | /* The contents of a character array is not meant to be NUL-terminated. */ | ||
| 143 | /* Applies to: struct/union members and variables that are arrays of element | ||
| 144 | type '[[un]signed] char'. */ | ||
| 145 | #define ATTRIBUTE_NONSTRING _GL_ATTRIBUTE_NONSTRING | ||
| 146 | |||
| 147 | /* Do not warn if control flow falls through to the immediately | ||
| 148 | following 'case' or 'default' label. */ | ||
| 149 | /* Applies to: Empty statement (;), inside a 'switch' statement. */ | ||
| 150 | #define FALLTHROUGH _GL_ATTRIBUTE_FALLTHROUGH | ||
| 151 | |||
| 152 | |||
| 153 | /* ================== Attributes for debugging information ================== */ | ||
| 154 | |||
| 155 | /* Attributes regarding debugging information emitted by the compiler. */ | ||
| 156 | |||
| 157 | /* Omit the function from stack traces when debugging. */ | ||
| 158 | /* Applies to: function. */ | ||
| 159 | #define ATTRIBUTE_ARTIFICIAL _GL_ATTRIBUTE_ARTIFICIAL | ||
| 160 | |||
| 161 | /* Make the entity visible to debuggers etc., even with '-fwhole-program'. */ | ||
| 162 | /* Applies to: functions, variables. */ | ||
| 163 | #define ATTRIBUTE_EXTERNALLY_VISIBLE _GL_ATTRIBUTE_EXTERNALLY_VISIBLE | ||
| 164 | |||
| 165 | |||
| 166 | /* ========== Attributes that mainly direct compiler optimizations ========== */ | ||
| 167 | |||
| 168 | /* The function does not throw exceptions. */ | ||
| 169 | /* Applies to: functions. */ | ||
| 170 | #define ATTRIBUTE_NOTHROW _GL_ATTRIBUTE_NOTHROW | ||
| 171 | |||
| 172 | /* Do not inline the function. */ | ||
| 173 | /* Applies to: functions. */ | ||
| 174 | #define ATTRIBUTE_NOINLINE _GL_ATTRIBUTE_NOINLINE | ||
| 175 | |||
| 176 | /* Always inline the function, and report an error if the compiler | ||
| 177 | cannot inline. */ | ||
| 178 | /* Applies to: function. */ | ||
| 179 | #define ATTRIBUTE_ALWAYS_INLINE _GL_ATTRIBUTE_ALWAYS_INLINE | ||
| 180 | |||
| 181 | /* It is OK for a compiler to omit duplicate calls with the same arguments. | ||
| 182 | This attribute is safe for a function that neither depends on | ||
| 183 | nor affects observable state, and always returns exactly once - | ||
| 184 | e.g., does not loop forever, and does not call longjmp. | ||
| 185 | (This attribute is stricter than ATTRIBUTE_PURE.) */ | ||
| 186 | /* Applies to: functions. */ | ||
| 187 | #define ATTRIBUTE_CONST _GL_ATTRIBUTE_CONST | ||
| 188 | |||
| 189 | /* It is OK for a compiler to omit duplicate calls with the same | ||
| 190 | arguments if observable state is not changed between calls. | ||
| 191 | This attribute is safe for a function that does not affect | ||
| 192 | observable state, and always returns exactly once. | ||
| 193 | (This attribute is looser than ATTRIBUTE_CONST.) */ | ||
| 194 | /* Applies to: functions. */ | ||
| 195 | #define ATTRIBUTE_PURE _GL_ATTRIBUTE_PURE | ||
| 196 | |||
| 197 | /* The function is rarely executed. */ | ||
| 198 | /* Applies to: functions. */ | ||
| 199 | #define ATTRIBUTE_COLD _GL_ATTRIBUTE_COLD | ||
| 200 | |||
| 201 | /* If called from some other compilation unit, the function executes | ||
| 202 | code from that unit only by return or by exception handling, | ||
| 203 | letting the compiler optimize that unit more aggressively. */ | ||
| 204 | /* Applies to: functions. */ | ||
| 205 | #define ATTRIBUTE_LEAF _GL_ATTRIBUTE_LEAF | ||
| 206 | |||
| 207 | /* For struct members: The member has the smallest possible alignment. | ||
| 208 | For struct, union, class: All members have the smallest possible alignment, | ||
| 209 | minimizing the memory required. */ | ||
| 210 | /* Applies to: struct members, struct, union, | ||
| 211 | in C++ also: class. */ | ||
| 212 | #define ATTRIBUTE_PACKED _GL_ATTRIBUTE_PACKED | ||
| 213 | |||
| 214 | |||
| 215 | /* ================ Attributes that make invalid code valid ================ */ | ||
| 216 | |||
| 217 | /* Attributes that prevent fatal compiler optimizations for code that is not | ||
| 218 | fully ISO C compliant. */ | ||
| 219 | |||
| 220 | /* Pointers to the type may point to the same storage as pointers to | ||
| 221 | other types, thus disabling strict aliasing optimization. */ | ||
| 222 | /* Applies to: types. */ | ||
| 223 | #define ATTRIBUTE_MAY_ALIAS _GL_ATTRIBUTE_MAY_ALIAS | ||
| 224 | |||
| 225 | |||
| 226 | #endif /* _GL_ATTRIBUTE_H */ | ||
