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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 | ||
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 | |
ae4d682d | 30 | # define __GCC4_has_attribute___assume_aligned__ 1 |
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 |
380d53c4 | 36 | # define __GCC4_has_attribute___no_profile_instrument_function__ 0 |
92676236 | 37 | # define __GCC4_has_attribute___nonstring__ 0 |
ae4d682d ND |
38 | # define __GCC4_has_attribute___no_sanitize_address__ 1 |
39 | # define __GCC4_has_attribute___no_sanitize_undefined__ 1 | |
294f69e6 | 40 | # define __GCC4_has_attribute___fallthrough__ 0 |
a3f8a30f MO |
41 | #endif |
42 | ||
43 | /* | |
44 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute | |
45 | */ | |
46 | #define __alias(symbol) __attribute__((__alias__(#symbol))) | |
47 | ||
48 | /* | |
49 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute | |
50 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute | |
51 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-aligned-variable-attribute | |
52 | */ | |
53 | #define __aligned(x) __attribute__((__aligned__(x))) | |
54 | #define __aligned_largest __attribute__((__aligned__)) | |
55 | ||
56 | /* | |
57 | * Note: users of __always_inline currently do not write "inline" themselves, | |
58 | * which seems to be required by gcc to apply the attribute according | |
59 | * to its docs (and also "warning: always_inline function might not be | |
60 | * inlinable [-Wattributes]" is emitted). | |
61 | * | |
62 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-always_005finline-function-attribute | |
63 | * clang: mentioned | |
64 | */ | |
65 | #define __always_inline inline __attribute__((__always_inline__)) | |
66 | ||
67 | /* | |
68 | * The second argument is optional (default 0), so we use a variadic macro | |
69 | * to make the shorthand. | |
70 | * | |
71 | * Beware: Do not apply this to functions which may return | |
72 | * ERR_PTRs. Also, it is probably unwise to apply it to functions | |
73 | * returning extra information in the low bits (but in that case the | |
74 | * compiler should see some alignment anyway, when the return value is | |
75 | * massaged by 'flags = ptr & 3; ptr &= ~3;'). | |
76 | * | |
77 | * Optional: only supported since gcc >= 4.9 | |
78 | * Optional: not supported by icc | |
79 | * | |
80 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute | |
81 | * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned | |
82 | */ | |
83 | #if __has_attribute(__assume_aligned__) | |
84 | # define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) | |
85 | #else | |
86 | # define __assume_aligned(a, ...) | |
87 | #endif | |
88 | ||
89 | /* | |
90 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute | |
91 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute | |
92 | */ | |
93 | #define __cold __attribute__((__cold__)) | |
94 | ||
95 | /* | |
96 | * Note the long name. | |
97 | * | |
98 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute | |
99 | */ | |
100 | #define __attribute_const__ __attribute__((__const__)) | |
101 | ||
c0d9782f MO |
102 | /* |
103 | * Optional: only supported since gcc >= 9 | |
104 | * Optional: not supported by clang | |
105 | * Optional: not supported by icc | |
106 | * | |
107 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute | |
108 | */ | |
109 | #if __has_attribute(__copy__) | |
110 | # define __copy(symbol) __attribute__((__copy__(symbol))) | |
111 | #else | |
112 | # define __copy(symbol) | |
113 | #endif | |
114 | ||
a3f8a30f MO |
115 | /* |
116 | * Don't. Just don't. See commit 771c035372a0 ("deprecate the '__deprecated' | |
117 | * attribute warnings entirely and for good") for more information. | |
118 | * | |
119 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-deprecated-function-attribute | |
120 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-deprecated-type-attribute | |
121 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-deprecated-variable-attribute | |
122 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Enumerator-Attributes.html#index-deprecated-enumerator-attribute | |
123 | * clang: https://clang.llvm.org/docs/AttributeReference.html#deprecated | |
124 | */ | |
125 | #define __deprecated | |
126 | ||
127 | /* | |
128 | * Optional: only supported since gcc >= 5.1 | |
129 | * Optional: not supported by clang | |
130 | * Optional: not supported by icc | |
131 | * | |
132 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute | |
133 | */ | |
134 | #if __has_attribute(__designated_init__) | |
135 | # define __designated_init __attribute__((__designated_init__)) | |
136 | #else | |
137 | # define __designated_init | |
138 | #endif | |
139 | ||
140 | /* | |
141 | * Optional: not supported by clang | |
142 | * | |
143 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-externally_005fvisible-function-attribute | |
144 | */ | |
145 | #if __has_attribute(__externally_visible__) | |
146 | # define __visible __attribute__((__externally_visible__)) | |
147 | #else | |
148 | # define __visible | |
149 | #endif | |
150 | ||
151 | /* | |
152 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-format-function-attribute | |
153 | * clang: https://clang.llvm.org/docs/AttributeReference.html#format | |
154 | */ | |
155 | #define __printf(a, b) __attribute__((__format__(printf, a, b))) | |
156 | #define __scanf(a, b) __attribute__((__format__(scanf, a, b))) | |
157 | ||
158 | /* | |
159 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-gnu_005finline-function-attribute | |
160 | * clang: https://clang.llvm.org/docs/AttributeReference.html#gnu-inline | |
161 | */ | |
162 | #define __gnu_inline __attribute__((__gnu_inline__)) | |
163 | ||
164 | /* | |
165 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute | |
166 | */ | |
167 | #define __malloc __attribute__((__malloc__)) | |
168 | ||
169 | /* | |
170 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-mode-type-attribute | |
171 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-mode-variable-attribute | |
172 | */ | |
173 | #define __mode(x) __attribute__((__mode__(x))) | |
174 | ||
feee1b8c AP |
175 | /* |
176 | * Optional: only supported since gcc >= 7 | |
177 | * | |
178 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-no_005fcaller_005fsaved_005fregisters-function-attribute_002c-x86 | |
179 | * clang: https://clang.llvm.org/docs/AttributeReference.html#no-caller-saved-registers | |
180 | */ | |
181 | #if __has_attribute(__no_caller_saved_registers__) | |
182 | # define __no_caller_saved_registers __attribute__((__no_caller_saved_registers__)) | |
183 | #else | |
184 | # define __no_caller_saved_registers | |
185 | #endif | |
186 | ||
a3f8a30f MO |
187 | /* |
188 | * Optional: not supported by clang | |
a3f8a30f MO |
189 | * |
190 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noclone-function-attribute | |
a3f8a30f MO |
191 | */ |
192 | #if __has_attribute(__noclone__) | |
2bcbd406 | 193 | # define __noclone __attribute__((__noclone__)) |
a3f8a30f MO |
194 | #else |
195 | # define __noclone | |
294f69e6 JP |
196 | #endif |
197 | ||
198 | /* | |
199 | * Add the pseudo keyword 'fallthrough' so case statement blocks | |
200 | * must end with any of these keywords: | |
201 | * break; | |
202 | * fallthrough; | |
ca0760e7 | 203 | * continue; |
294f69e6 JP |
204 | * goto <label>; |
205 | * return [expression]; | |
206 | * | |
207 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes | |
208 | */ | |
209 | #if __has_attribute(__fallthrough__) | |
210 | # define fallthrough __attribute__((__fallthrough__)) | |
211 | #else | |
212 | # define fallthrough do {} while (0) /* fallthrough */ | |
a3f8a30f MO |
213 | #endif |
214 | ||
258e0815 DZ |
215 | /* |
216 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes | |
217 | * clang: https://clang.llvm.org/docs/AttributeReference.html#flatten | |
218 | */ | |
219 | # define __flatten __attribute__((flatten)) | |
220 | ||
a3f8a30f MO |
221 | /* |
222 | * Note the missing underscores. | |
223 | * | |
224 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute | |
225 | * clang: mentioned | |
226 | */ | |
227 | #define noinline __attribute__((__noinline__)) | |
228 | ||
92676236 MO |
229 | /* |
230 | * Optional: only supported since gcc >= 8 | |
231 | * Optional: not supported by clang | |
232 | * Optional: not supported by icc | |
233 | * | |
234 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute | |
235 | */ | |
236 | #if __has_attribute(__nonstring__) | |
237 | # define __nonstring __attribute__((__nonstring__)) | |
238 | #else | |
239 | # define __nonstring | |
240 | #endif | |
241 | ||
380d53c4 ND |
242 | /* |
243 | * Optional: only supported since GCC >= 7.1, clang >= 13.0. | |
244 | * | |
245 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-no_005fprofile_005finstrument_005ffunction-function-attribute | |
246 | * clang: https://clang.llvm.org/docs/AttributeReference.html#no-profile-instrument-function | |
247 | */ | |
248 | #if __has_attribute(__no_profile_instrument_function__) | |
249 | # define __no_profile __attribute__((__no_profile_instrument_function__)) | |
250 | #else | |
251 | # define __no_profile | |
252 | #endif | |
253 | ||
a3f8a30f MO |
254 | /* |
255 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute | |
256 | * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn | |
257 | * clang: https://clang.llvm.org/docs/AttributeReference.html#id1 | |
258 | */ | |
259 | #define __noreturn __attribute__((__noreturn__)) | |
260 | ||
a3f8a30f MO |
261 | /* |
262 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute | |
263 | * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute | |
264 | */ | |
265 | #define __packed __attribute__((__packed__)) | |
266 | ||
267 | /* | |
268 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute | |
269 | */ | |
270 | #define __pure __attribute__((__pure__)) | |
271 | ||
272 | /* | |
273 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute | |
274 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute | |
275 | * clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate | |
276 | */ | |
33def849 | 277 | #define __section(section) __attribute__((__section__(section))) |
a3f8a30f MO |
278 | |
279 | /* | |
280 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-unused-function-attribute | |
281 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-unused-type-attribute | |
282 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-unused-variable-attribute | |
283 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-unused-label-attribute | |
284 | * clang: https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused | |
285 | */ | |
286 | #define __always_unused __attribute__((__unused__)) | |
287 | #define __maybe_unused __attribute__((__unused__)) | |
288 | ||
289 | /* | |
290 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-used-function-attribute | |
291 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-used-variable-attribute | |
292 | */ | |
293 | #define __used __attribute__((__used__)) | |
294 | ||
19679394 MY |
295 | /* |
296 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-warn_005funused_005fresult-function-attribute | |
297 | * clang: https://clang.llvm.org/docs/AttributeReference.html#nodiscard-warn-unused-result | |
298 | */ | |
299 | #define __must_check __attribute__((__warn_unused_result__)) | |
300 | ||
a3f8a30f MO |
301 | /* |
302 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute | |
303 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute | |
304 | */ | |
305 | #define __weak __attribute__((__weak__)) | |
306 | ||
307 | #endif /* __LINUX_COMPILER_ATTRIBUTES_H */ |