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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 | ||
a3f8a30f MO |
23 | /* |
24 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute | |
25 | */ | |
26 | #define __alias(symbol) __attribute__((__alias__(#symbol))) | |
27 | ||
28 | /* | |
29 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute | |
30 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute | |
31 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-aligned-variable-attribute | |
32 | */ | |
33 | #define __aligned(x) __attribute__((__aligned__(x))) | |
34 | #define __aligned_largest __attribute__((__aligned__)) | |
35 | ||
86cffecd KC |
36 | /* |
37 | * Note: do not use this directly. Instead, use __alloc_size() since it is conditionally | |
38 | * available and includes other attributes. | |
39 | * | |
40 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alloc_005fsize-function-attribute | |
41 | * clang: https://clang.llvm.org/docs/AttributeReference.html#alloc-size | |
42 | */ | |
43 | #define __alloc_size__(x, ...) __attribute__((__alloc_size__(x, ## __VA_ARGS__))) | |
44 | ||
a3f8a30f MO |
45 | /* |
46 | * Note: users of __always_inline currently do not write "inline" themselves, | |
47 | * which seems to be required by gcc to apply the attribute according | |
48 | * to its docs (and also "warning: always_inline function might not be | |
49 | * inlinable [-Wattributes]" is emitted). | |
50 | * | |
51 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-always_005finline-function-attribute | |
52 | * clang: mentioned | |
53 | */ | |
54 | #define __always_inline inline __attribute__((__always_inline__)) | |
55 | ||
56 | /* | |
57 | * The second argument is optional (default 0), so we use a variadic macro | |
58 | * to make the shorthand. | |
59 | * | |
60 | * Beware: Do not apply this to functions which may return | |
61 | * ERR_PTRs. Also, it is probably unwise to apply it to functions | |
62 | * returning extra information in the low bits (but in that case the | |
63 | * compiler should see some alignment anyway, when the return value is | |
64 | * massaged by 'flags = ptr & 3; ptr &= ~3;'). | |
65 | * | |
a3f8a30f MO |
66 | * Optional: not supported by icc |
67 | * | |
68 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute | |
69 | * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned | |
70 | */ | |
71 | #if __has_attribute(__assume_aligned__) | |
72 | # define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) | |
73 | #else | |
74 | # define __assume_aligned(a, ...) | |
75 | #endif | |
76 | ||
77 | /* | |
78 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute | |
79 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute | |
80 | */ | |
81 | #define __cold __attribute__((__cold__)) | |
82 | ||
83 | /* | |
84 | * Note the long name. | |
85 | * | |
86 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute | |
87 | */ | |
88 | #define __attribute_const__ __attribute__((__const__)) | |
89 | ||
c0d9782f MO |
90 | /* |
91 | * Optional: only supported since gcc >= 9 | |
92 | * Optional: not supported by clang | |
93 | * Optional: not supported by icc | |
94 | * | |
95 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute | |
96 | */ | |
97 | #if __has_attribute(__copy__) | |
98 | # define __copy(symbol) __attribute__((__copy__(symbol))) | |
99 | #else | |
100 | # define __copy(symbol) | |
101 | #endif | |
102 | ||
a3f8a30f MO |
103 | /* |
104 | * Don't. Just don't. See commit 771c035372a0 ("deprecate the '__deprecated' | |
105 | * attribute warnings entirely and for good") for more information. | |
106 | * | |
107 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-deprecated-function-attribute | |
108 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-deprecated-type-attribute | |
109 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-deprecated-variable-attribute | |
110 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Enumerator-Attributes.html#index-deprecated-enumerator-attribute | |
111 | * clang: https://clang.llvm.org/docs/AttributeReference.html#deprecated | |
112 | */ | |
113 | #define __deprecated | |
114 | ||
115 | /* | |
a3f8a30f MO |
116 | * Optional: not supported by clang |
117 | * Optional: not supported by icc | |
118 | * | |
119 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute | |
120 | */ | |
121 | #if __has_attribute(__designated_init__) | |
122 | # define __designated_init __attribute__((__designated_init__)) | |
123 | #else | |
124 | # define __designated_init | |
125 | #endif | |
126 | ||
b83a9084 ND |
127 | /* |
128 | * Optional: only supported since clang >= 14.0 | |
129 | * | |
130 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute | |
131 | */ | |
132 | #if __has_attribute(__error__) | |
133 | # define __compiletime_error(msg) __attribute__((__error__(msg))) | |
134 | #else | |
135 | # define __compiletime_error(msg) | |
136 | #endif | |
137 | ||
a3f8a30f MO |
138 | /* |
139 | * Optional: not supported by clang | |
140 | * | |
141 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-externally_005fvisible-function-attribute | |
142 | */ | |
143 | #if __has_attribute(__externally_visible__) | |
144 | # define __visible __attribute__((__externally_visible__)) | |
145 | #else | |
146 | # define __visible | |
147 | #endif | |
148 | ||
149 | /* | |
150 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-format-function-attribute | |
151 | * clang: https://clang.llvm.org/docs/AttributeReference.html#format | |
152 | */ | |
153 | #define __printf(a, b) __attribute__((__format__(printf, a, b))) | |
154 | #define __scanf(a, b) __attribute__((__format__(scanf, a, b))) | |
155 | ||
156 | /* | |
157 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-gnu_005finline-function-attribute | |
158 | * clang: https://clang.llvm.org/docs/AttributeReference.html#gnu-inline | |
159 | */ | |
160 | #define __gnu_inline __attribute__((__gnu_inline__)) | |
161 | ||
162 | /* | |
163 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute | |
86cffecd | 164 | * clang: https://clang.llvm.org/docs/AttributeReference.html#malloc |
a3f8a30f MO |
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; | |
ca0760e7 | 202 | * continue; |
294f69e6 JP |
203 | * goto <label>; |
204 | * return [expression]; | |
205 | * | |
206 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes | |
207 | */ | |
208 | #if __has_attribute(__fallthrough__) | |
209 | # define fallthrough __attribute__((__fallthrough__)) | |
210 | #else | |
211 | # define fallthrough do {} while (0) /* fallthrough */ | |
a3f8a30f MO |
212 | #endif |
213 | ||
258e0815 DZ |
214 | /* |
215 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes | |
216 | * clang: https://clang.llvm.org/docs/AttributeReference.html#flatten | |
217 | */ | |
218 | # define __flatten __attribute__((flatten)) | |
219 | ||
a3f8a30f MO |
220 | /* |
221 | * Note the missing underscores. | |
222 | * | |
223 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute | |
224 | * clang: mentioned | |
225 | */ | |
226 | #define noinline __attribute__((__noinline__)) | |
227 | ||
92676236 MO |
228 | /* |
229 | * Optional: only supported since gcc >= 8 | |
230 | * Optional: not supported by clang | |
231 | * Optional: not supported by icc | |
232 | * | |
233 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute | |
234 | */ | |
235 | #if __has_attribute(__nonstring__) | |
236 | # define __nonstring __attribute__((__nonstring__)) | |
237 | #else | |
238 | # define __nonstring | |
239 | #endif | |
240 | ||
380d53c4 ND |
241 | /* |
242 | * Optional: only supported since GCC >= 7.1, clang >= 13.0. | |
243 | * | |
244 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fprofile_005finstrument_005ffunction-function-attribute | |
245 | * clang: https://clang.llvm.org/docs/AttributeReference.html#no-profile-instrument-function | |
246 | */ | |
247 | #if __has_attribute(__no_profile_instrument_function__) | |
248 | # define __no_profile __attribute__((__no_profile_instrument_function__)) | |
249 | #else | |
250 | # define __no_profile | |
251 | #endif | |
252 | ||
a3f8a30f MO |
253 | /* |
254 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute | |
255 | * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn | |
256 | * clang: https://clang.llvm.org/docs/AttributeReference.html#id1 | |
257 | */ | |
258 | #define __noreturn __attribute__((__noreturn__)) | |
259 | ||
a3f8a30f MO |
260 | /* |
261 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute | |
262 | * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute | |
263 | */ | |
264 | #define __packed __attribute__((__packed__)) | |
265 | ||
266 | /* | |
267 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute | |
268 | */ | |
269 | #define __pure __attribute__((__pure__)) | |
270 | ||
271 | /* | |
272 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute | |
273 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute | |
274 | * clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate | |
275 | */ | |
33def849 | 276 | #define __section(section) __attribute__((__section__(section))) |
a3f8a30f MO |
277 | |
278 | /* | |
279 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-unused-function-attribute | |
280 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-unused-type-attribute | |
281 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-unused-variable-attribute | |
282 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-unused-label-attribute | |
283 | * clang: https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused | |
284 | */ | |
285 | #define __always_unused __attribute__((__unused__)) | |
286 | #define __maybe_unused __attribute__((__unused__)) | |
287 | ||
288 | /* | |
289 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-used-function-attribute | |
290 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-used-variable-attribute | |
291 | */ | |
292 | #define __used __attribute__((__used__)) | |
293 | ||
19679394 MY |
294 | /* |
295 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warn_005funused_005fresult-function-attribute | |
296 | * clang: https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result | |
297 | */ | |
298 | #define __must_check __attribute__((__warn_unused_result__)) | |
299 | ||
b83a9084 ND |
300 | /* |
301 | * Optional: only supported since clang >= 14.0 | |
302 | * | |
303 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warning-function-attribute | |
304 | */ | |
305 | #if __has_attribute(__warning__) | |
306 | # define __compiletime_warning(msg) __attribute__((__warning__(msg))) | |
307 | #else | |
308 | # define __compiletime_warning(msg) | |
309 | #endif | |
310 | ||
a015b708 AP |
311 | /* |
312 | * Optional: only supported since clang >= 14.0 | |
313 | * | |
314 | * clang: https://clang.llvm.org/docs/AttributeReference.html#disable-sanitizer-instrumentation | |
315 | * | |
316 | * disable_sanitizer_instrumentation is not always similar to | |
317 | * no_sanitize((<sanitizer-name>)): the latter may still let specific sanitizers | |
318 | * insert code into functions to prevent false positives. Unlike that, | |
319 | * disable_sanitizer_instrumentation prevents all kinds of instrumentation to | |
320 | * functions with the attribute. | |
321 | */ | |
322 | #if __has_attribute(disable_sanitizer_instrumentation) | |
323 | # define __disable_sanitizer_instrumentation \ | |
324 | __attribute__((disable_sanitizer_instrumentation)) | |
325 | #else | |
326 | # define __disable_sanitizer_instrumentation | |
327 | #endif | |
328 | ||
a3f8a30f MO |
329 | /* |
330 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute | |
331 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute | |
332 | */ | |
333 | #define __weak __attribute__((__weak__)) | |
334 | ||
335 | #endif /* __LINUX_COMPILER_ATTRIBUTES_H */ |