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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 MO |
24 | * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17. |
25 | * In the meantime, to support 4.6 <= gcc < 5, we implement __has_attribute | |
26 | * by hand. | |
a3f8a30f MO |
27 | * |
28 | * sparse does not support __has_attribute (yet) and defines __GNUC_MINOR__ | |
29 | * depending on the compiler used to build it; however, these attributes have | |
30 | * no semantic effects for sparse, so it does not matter. Also note that, | |
31 | * in order to avoid sparse's warnings, even the unsupported ones must be | |
32 | * defined to 0. | |
33 | */ | |
34 | #ifndef __has_attribute | |
35 | # define __has_attribute(x) __GCC4_has_attribute_##x | |
36 | # define __GCC4_has_attribute___assume_aligned__ (__GNUC_MINOR__ >= 9) | |
c0d9782f | 37 | # define __GCC4_has_attribute___copy__ 0 |
a3f8a30f MO |
38 | # define __GCC4_has_attribute___designated_init__ 0 |
39 | # define __GCC4_has_attribute___externally_visible__ 1 | |
40 | # define __GCC4_has_attribute___noclone__ 1 | |
92676236 | 41 | # define __GCC4_has_attribute___nonstring__ 0 |
a3f8a30f | 42 | # define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8) |
294f69e6 | 43 | # define __GCC4_has_attribute___fallthrough__ 0 |
a3f8a30f MO |
44 | #endif |
45 | ||
46 | /* | |
47 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute | |
48 | */ | |
49 | #define __alias(symbol) __attribute__((__alias__(#symbol))) | |
50 | ||
51 | /* | |
52 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute | |
53 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute | |
54 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-aligned-variable-attribute | |
55 | */ | |
56 | #define __aligned(x) __attribute__((__aligned__(x))) | |
57 | #define __aligned_largest __attribute__((__aligned__)) | |
58 | ||
59 | /* | |
60 | * Note: users of __always_inline currently do not write "inline" themselves, | |
61 | * which seems to be required by gcc to apply the attribute according | |
62 | * to its docs (and also "warning: always_inline function might not be | |
63 | * inlinable [-Wattributes]" is emitted). | |
64 | * | |
65 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-always_005finline-function-attribute | |
66 | * clang: mentioned | |
67 | */ | |
68 | #define __always_inline inline __attribute__((__always_inline__)) | |
69 | ||
70 | /* | |
71 | * The second argument is optional (default 0), so we use a variadic macro | |
72 | * to make the shorthand. | |
73 | * | |
74 | * Beware: Do not apply this to functions which may return | |
75 | * ERR_PTRs. Also, it is probably unwise to apply it to functions | |
76 | * returning extra information in the low bits (but in that case the | |
77 | * compiler should see some alignment anyway, when the return value is | |
78 | * massaged by 'flags = ptr & 3; ptr &= ~3;'). | |
79 | * | |
80 | * Optional: only supported since gcc >= 4.9 | |
81 | * Optional: not supported by icc | |
82 | * | |
83 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute | |
84 | * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned | |
85 | */ | |
86 | #if __has_attribute(__assume_aligned__) | |
87 | # define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) | |
88 | #else | |
89 | # define __assume_aligned(a, ...) | |
90 | #endif | |
91 | ||
92 | /* | |
93 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute | |
94 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute | |
95 | */ | |
96 | #define __cold __attribute__((__cold__)) | |
97 | ||
98 | /* | |
99 | * Note the long name. | |
100 | * | |
101 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute | |
102 | */ | |
103 | #define __attribute_const__ __attribute__((__const__)) | |
104 | ||
c0d9782f MO |
105 | /* |
106 | * Optional: only supported since gcc >= 9 | |
107 | * Optional: not supported by clang | |
108 | * Optional: not supported by icc | |
109 | * | |
110 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute | |
111 | */ | |
112 | #if __has_attribute(__copy__) | |
113 | # define __copy(symbol) __attribute__((__copy__(symbol))) | |
114 | #else | |
115 | # define __copy(symbol) | |
116 | #endif | |
117 | ||
a3f8a30f MO |
118 | /* |
119 | * Don't. Just don't. See commit 771c035372a0 ("deprecate the '__deprecated' | |
120 | * attribute warnings entirely and for good") for more information. | |
121 | * | |
122 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-deprecated-function-attribute | |
123 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-deprecated-type-attribute | |
124 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-deprecated-variable-attribute | |
125 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Enumerator-Attributes.html#index-deprecated-enumerator-attribute | |
126 | * clang: https://clang.llvm.org/docs/AttributeReference.html#deprecated | |
127 | */ | |
128 | #define __deprecated | |
129 | ||
130 | /* | |
131 | * Optional: only supported since gcc >= 5.1 | |
132 | * Optional: not supported by clang | |
133 | * Optional: not supported by icc | |
134 | * | |
135 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute | |
136 | */ | |
137 | #if __has_attribute(__designated_init__) | |
138 | # define __designated_init __attribute__((__designated_init__)) | |
139 | #else | |
140 | # define __designated_init | |
141 | #endif | |
142 | ||
143 | /* | |
144 | * Optional: not supported by clang | |
145 | * | |
146 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-externally_005fvisible-function-attribute | |
147 | */ | |
148 | #if __has_attribute(__externally_visible__) | |
149 | # define __visible __attribute__((__externally_visible__)) | |
150 | #else | |
151 | # define __visible | |
152 | #endif | |
153 | ||
154 | /* | |
155 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-format-function-attribute | |
156 | * clang: https://clang.llvm.org/docs/AttributeReference.html#format | |
157 | */ | |
158 | #define __printf(a, b) __attribute__((__format__(printf, a, b))) | |
159 | #define __scanf(a, b) __attribute__((__format__(scanf, a, b))) | |
160 | ||
161 | /* | |
162 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-gnu_005finline-function-attribute | |
163 | * clang: https://clang.llvm.org/docs/AttributeReference.html#gnu-inline | |
164 | */ | |
165 | #define __gnu_inline __attribute__((__gnu_inline__)) | |
166 | ||
167 | /* | |
168 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute | |
169 | */ | |
170 | #define __malloc __attribute__((__malloc__)) | |
171 | ||
172 | /* | |
173 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-mode-type-attribute | |
174 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-mode-variable-attribute | |
175 | */ | |
176 | #define __mode(x) __attribute__((__mode__(x))) | |
177 | ||
178 | /* | |
179 | * Optional: not supported by clang | |
a3f8a30f MO |
180 | * |
181 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noclone-function-attribute | |
a3f8a30f MO |
182 | */ |
183 | #if __has_attribute(__noclone__) | |
2bcbd406 | 184 | # define __noclone __attribute__((__noclone__)) |
a3f8a30f MO |
185 | #else |
186 | # define __noclone | |
294f69e6 JP |
187 | #endif |
188 | ||
189 | /* | |
190 | * Add the pseudo keyword 'fallthrough' so case statement blocks | |
191 | * must end with any of these keywords: | |
192 | * break; | |
193 | * fallthrough; | |
194 | * goto <label>; | |
195 | * return [expression]; | |
196 | * | |
197 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes | |
198 | */ | |
199 | #if __has_attribute(__fallthrough__) | |
200 | # define fallthrough __attribute__((__fallthrough__)) | |
201 | #else | |
202 | # define fallthrough do {} while (0) /* fallthrough */ | |
a3f8a30f MO |
203 | #endif |
204 | ||
205 | /* | |
206 | * Note the missing underscores. | |
207 | * | |
208 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute | |
209 | * clang: mentioned | |
210 | */ | |
211 | #define noinline __attribute__((__noinline__)) | |
212 | ||
92676236 MO |
213 | /* |
214 | * Optional: only supported since gcc >= 8 | |
215 | * Optional: not supported by clang | |
216 | * Optional: not supported by icc | |
217 | * | |
218 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute | |
219 | */ | |
220 | #if __has_attribute(__nonstring__) | |
221 | # define __nonstring __attribute__((__nonstring__)) | |
222 | #else | |
223 | # define __nonstring | |
224 | #endif | |
225 | ||
a3f8a30f MO |
226 | /* |
227 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute | |
228 | * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn | |
229 | * clang: https://clang.llvm.org/docs/AttributeReference.html#id1 | |
230 | */ | |
231 | #define __noreturn __attribute__((__noreturn__)) | |
232 | ||
a3f8a30f MO |
233 | /* |
234 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute | |
235 | * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute | |
236 | */ | |
237 | #define __packed __attribute__((__packed__)) | |
238 | ||
239 | /* | |
240 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute | |
241 | */ | |
242 | #define __pure __attribute__((__pure__)) | |
243 | ||
244 | /* | |
245 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute | |
246 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute | |
247 | * clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate | |
248 | */ | |
249 | #define __section(S) __attribute__((__section__(#S))) | |
250 | ||
251 | /* | |
252 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-unused-function-attribute | |
253 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-unused-type-attribute | |
254 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-unused-variable-attribute | |
255 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-unused-label-attribute | |
256 | * clang: https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused | |
257 | */ | |
258 | #define __always_unused __attribute__((__unused__)) | |
259 | #define __maybe_unused __attribute__((__unused__)) | |
260 | ||
261 | /* | |
262 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-used-function-attribute | |
263 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-used-variable-attribute | |
264 | */ | |
265 | #define __used __attribute__((__used__)) | |
266 | ||
267 | /* | |
268 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute | |
269 | * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute | |
270 | */ | |
271 | #define __weak __attribute__((__weak__)) | |
272 | ||
273 | #endif /* __LINUX_COMPILER_ATTRIBUTES_H */ |