Commit | Line | Data |
---|---|---|
a3f8a30f MO |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __LINUX_COMPILER_ATTRIBUTES_H | |
3 | #define __LINUX_COMPILER_ATTRIBUTES_H | |
4 | ||
5 | /* | |
6 | * The attributes in this file are unconditionally defined and they directly | |
24efee41 MO |
7 | * map to compiler attribute(s), unless one of the compilers does not support |
8 | * the attribute. In that case, __has_attribute is used to check for support | |
9 | * and the reason is stated in its comment ("Optional: ..."). | |
a3f8a30f MO |
10 | * |
11 | * Any other "attributes" (i.e. those that depend on a configuration option, | |
12 | * on a compiler, on an architecture, on plugins, on other attributes...) | |
13 | * should be defined elsewhere (e.g. compiler_types.h or compiler-*.h). | |
24efee41 MO |
14 | * The intention is to keep this file as simple as possible, as well as |
15 | * compiler- and version-agnostic (e.g. avoiding GCC_VERSION checks). | |
a3f8a30f MO |
16 | * |
17 | * This file is meant to be sorted (by actual attribute name, | |
18 | * not by #define identifier). Use the __attribute__((__name__)) syntax | |
19 | * (i.e. with underscores) to avoid future collisions with other macros. | |
24efee41 | 20 | * Provide links to the documentation of each supported compiler, if it exists. |
a3f8a30f MO |
21 | */ |
22 | ||
23 | /* | |
24efee41 | 24 | * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17. |
5861af92 | 25 | * In the meantime, to support gcc < 5, we implement __has_attribute |
24efee41 | 26 | * by hand. |
a3f8a30f MO |
27 | */ |
28 | #ifndef __has_attribute | |
29 | # define __has_attribute(x) __GCC4_has_attribute_##x | |
30 | # define __GCC4_has_attribute___assume_aligned__ (__GNUC_MINOR__ >= 9) | |
c0d9782f | 31 | # define __GCC4_has_attribute___copy__ 0 |
a3f8a30f MO |
32 | # define __GCC4_has_attribute___designated_init__ 0 |
33 | # define __GCC4_has_attribute___externally_visible__ 1 | |
feee1b8c | 34 | # define __GCC4_has_attribute___no_caller_saved_registers__ 0 |
a3f8a30f | 35 | # define __GCC4_has_attribute___noclone__ 1 |
92676236 | 36 | # define __GCC4_has_attribute___nonstring__ 0 |
a3f8a30f | 37 | # define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8) |
33aea07f | 38 | # define __GCC4_has_attribute___no_sanitize_undefined__ (__GNUC_MINOR__ >= 9) |
294f69e6 | 39 | # define __GCC4_has_attribute___fallthrough__ 0 |
a3f8a30f MO |
40 | #endif |
41 | ||
42 | /* | |
43 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute | |
44 | */ | |
45 | #define __alias(symbol) __attribute__((__alias__(#symbol))) | |
46 | ||
47 | /* | |
48 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute | |
49 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute | |
50 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-aligned-variable-attribute | |
51 | */ | |
52 | #define __aligned(x) __attribute__((__aligned__(x))) | |
53 | #define __aligned_largest __attribute__((__aligned__)) | |
54 | ||
55 | /* | |
56 | * Note: users of __always_inline currently do not write "inline" themselves, | |
57 | * which seems to be required by gcc to apply the attribute according | |
58 | * to its docs (and also "warning: always_inline function might not be | |
59 | * inlinable [-Wattributes]" is emitted). | |
60 | * | |
61 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-always_005finline-function-attribute | |
62 | * clang: mentioned | |
63 | */ | |
64 | #define __always_inline inline __attribute__((__always_inline__)) | |
65 | ||
66 | /* | |
67 | * The second argument is optional (default 0), so we use a variadic macro | |
68 | * to make the shorthand. | |
69 | * | |
70 | * Beware: Do not apply this to functions which may return | |
71 | * ERR_PTRs. Also, it is probably unwise to apply it to functions | |
72 | * returning extra information in the low bits (but in that case the | |
73 | * compiler should see some alignment anyway, when the return value is | |
74 | * massaged by 'flags = ptr & 3; ptr &= ~3;'). | |
75 | * | |
76 | * Optional: only supported since gcc >= 4.9 | |
77 | * Optional: not supported by icc | |
78 | * | |
79 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute | |
80 | * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned | |
81 | */ | |
82 | #if __has_attribute(__assume_aligned__) | |
83 | # define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) | |
84 | #else | |
85 | # define __assume_aligned(a, ...) | |
86 | #endif | |
87 | ||
88 | /* | |
89 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute | |
90 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute | |
91 | */ | |
92 | #define __cold __attribute__((__cold__)) | |
93 | ||
94 | /* | |
95 | * Note the long name. | |
96 | * | |
97 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute | |
98 | */ | |
99 | #define __attribute_const__ __attribute__((__const__)) | |
100 | ||
c0d9782f MO |
101 | /* |
102 | * Optional: only supported since gcc >= 9 | |
103 | * Optional: not supported by clang | |
104 | * Optional: not supported by icc | |
105 | * | |
106 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute | |
107 | */ | |
108 | #if __has_attribute(__copy__) | |
109 | # define __copy(symbol) __attribute__((__copy__(symbol))) | |
110 | #else | |
111 | # define __copy(symbol) | |
112 | #endif | |
113 | ||
a3f8a30f MO |
114 | /* |
115 | * Don't. Just don't. See commit 771c035372a0 ("deprecate the '__deprecated' | |
116 | * attribute warnings entirely and for good") for more information. | |
117 | * | |
118 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-deprecated-function-attribute | |
119 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-deprecated-type-attribute | |
120 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-deprecated-variable-attribute | |
121 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Enumerator-Attributes.html#index-deprecated-enumerator-attribute | |
122 | * clang: https://clang.llvm.org/docs/AttributeReference.html#deprecated | |
123 | */ | |
124 | #define __deprecated | |
125 | ||
126 | /* | |
127 | * Optional: only supported since gcc >= 5.1 | |
128 | * Optional: not supported by clang | |
129 | * Optional: not supported by icc | |
130 | * | |
131 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute | |
132 | */ | |
133 | #if __has_attribute(__designated_init__) | |
134 | # define __designated_init __attribute__((__designated_init__)) | |
135 | #else | |
136 | # define __designated_init | |
137 | #endif | |
138 | ||
139 | /* | |
140 | * Optional: not supported by clang | |
141 | * | |
142 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-externally_005fvisible-function-attribute | |
143 | */ | |
144 | #if __has_attribute(__externally_visible__) | |
145 | # define __visible __attribute__((__externally_visible__)) | |
146 | #else | |
147 | # define __visible | |
148 | #endif | |
149 | ||
150 | /* | |
151 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-format-function-attribute | |
152 | * clang: https://clang.llvm.org/docs/AttributeReference.html#format | |
153 | */ | |
154 | #define __printf(a, b) __attribute__((__format__(printf, a, b))) | |
155 | #define __scanf(a, b) __attribute__((__format__(scanf, a, b))) | |
156 | ||
157 | /* | |
158 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-gnu_005finline-function-attribute | |
159 | * clang: https://clang.llvm.org/docs/AttributeReference.html#gnu-inline | |
160 | */ | |
161 | #define __gnu_inline __attribute__((__gnu_inline__)) | |
162 | ||
163 | /* | |
164 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute | |
165 | */ | |
166 | #define __malloc __attribute__((__malloc__)) | |
167 | ||
168 | /* | |
169 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-mode-type-attribute | |
170 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-mode-variable-attribute | |
171 | */ | |
172 | #define __mode(x) __attribute__((__mode__(x))) | |
173 | ||
feee1b8c AP |
174 | /* |
175 | * Optional: only supported since gcc >= 7 | |
176 | * | |
177 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-no_005fcaller_005fsaved_005fregisters-function-attribute_002c-x86 | |
178 | * clang: https://clang.llvm.org/docs/AttributeReference.html#no-caller-saved-registers | |
179 | */ | |
180 | #if __has_attribute(__no_caller_saved_registers__) | |
181 | # define __no_caller_saved_registers __attribute__((__no_caller_saved_registers__)) | |
182 | #else | |
183 | # define __no_caller_saved_registers | |
184 | #endif | |
185 | ||
a3f8a30f MO |
186 | /* |
187 | * Optional: not supported by clang | |
a3f8a30f MO |
188 | * |
189 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noclone-function-attribute | |
a3f8a30f MO |
190 | */ |
191 | #if __has_attribute(__noclone__) | |
2bcbd406 | 192 | # define __noclone __attribute__((__noclone__)) |
a3f8a30f MO |
193 | #else |
194 | # define __noclone | |
294f69e6 JP |
195 | #endif |
196 | ||
197 | /* | |
198 | * Add the pseudo keyword 'fallthrough' so case statement blocks | |
199 | * must end with any of these keywords: | |
200 | * break; | |
201 | * fallthrough; | |
202 | * goto <label>; | |
203 | * return [expression]; | |
204 | * | |
205 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes | |
206 | */ | |
207 | #if __has_attribute(__fallthrough__) | |
208 | # define fallthrough __attribute__((__fallthrough__)) | |
209 | #else | |
210 | # define fallthrough do {} while (0) /* fallthrough */ | |
a3f8a30f MO |
211 | #endif |
212 | ||
258e0815 DZ |
213 | /* |
214 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes | |
215 | * clang: https://clang.llvm.org/docs/AttributeReference.html#flatten | |
216 | */ | |
217 | # define __flatten __attribute__((flatten)) | |
218 | ||
a3f8a30f MO |
219 | /* |
220 | * Note the missing underscores. | |
221 | * | |
222 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute | |
223 | * clang: mentioned | |
224 | */ | |
225 | #define noinline __attribute__((__noinline__)) | |
226 | ||
92676236 MO |
227 | /* |
228 | * Optional: only supported since gcc >= 8 | |
229 | * Optional: not supported by clang | |
230 | * Optional: not supported by icc | |
231 | * | |
232 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute | |
233 | */ | |
234 | #if __has_attribute(__nonstring__) | |
235 | # define __nonstring __attribute__((__nonstring__)) | |
236 | #else | |
237 | # define __nonstring | |
238 | #endif | |
239 | ||
a3f8a30f MO |
240 | /* |
241 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute | |
242 | * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn | |
243 | * clang: https://clang.llvm.org/docs/AttributeReference.html#id1 | |
244 | */ | |
245 | #define __noreturn __attribute__((__noreturn__)) | |
246 | ||
a3f8a30f MO |
247 | /* |
248 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute | |
249 | * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute | |
250 | */ | |
251 | #define __packed __attribute__((__packed__)) | |
252 | ||
253 | /* | |
254 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute | |
255 | */ | |
256 | #define __pure __attribute__((__pure__)) | |
257 | ||
258 | /* | |
259 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute | |
260 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute | |
261 | * clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate | |
262 | */ | |
33def849 | 263 | #define __section(section) __attribute__((__section__(section))) |
a3f8a30f MO |
264 | |
265 | /* | |
266 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-unused-function-attribute | |
267 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-unused-type-attribute | |
268 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-unused-variable-attribute | |
269 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-unused-label-attribute | |
270 | * clang: https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused | |
271 | */ | |
272 | #define __always_unused __attribute__((__unused__)) | |
273 | #define __maybe_unused __attribute__((__unused__)) | |
274 | ||
275 | /* | |
276 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-used-function-attribute | |
277 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-used-variable-attribute | |
278 | */ | |
279 | #define __used __attribute__((__used__)) | |
280 | ||
19679394 MY |
281 | /* |
282 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warn_005funused_005fresult-function-attribute | |
283 | * clang: https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result | |
284 | */ | |
285 | #define __must_check __attribute__((__warn_unused_result__)) | |
286 | ||
a3f8a30f MO |
287 | /* |
288 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute | |
289 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute | |
290 | */ | |
291 | #define __weak __attribute__((__weak__)) | |
292 | ||
293 | #endif /* __LINUX_COMPILER_ATTRIBUTES_H */ |