diff options
Diffstat (limited to 'include/linux/compiler_attributes.h')
| -rw-r--r-- | include/linux/compiler_attributes.h | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h new file mode 100644 index 0000000000..6b318efd8a --- /dev/null +++ b/include/linux/compiler_attributes.h @@ -0,0 +1,256 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __LINUX_COMPILER_ATTRIBUTES_H +#define __LINUX_COMPILER_ATTRIBUTES_H + +/* + * The attributes in this file are unconditionally defined and they directly + * map to compiler attribute(s), unless one of the compilers does not support + * the attribute. In that case, __has_attribute is used to check for support + * and the reason is stated in its comment ("Optional: ..."). + * + * Any other "attributes" (i.e. those that depend on a configuration option, + * on a compiler, on an architecture, on plugins, on other attributes...) + * should be defined elsewhere (e.g. compiler_types.h or compiler-*.h). + * The intention is to keep this file as simple as possible, as well as + * compiler- and version-agnostic (e.g. avoiding GCC_VERSION checks). + * + * This file is meant to be sorted (by actual attribute name, + * not by #define identifier). Use the __attribute__((__name__)) syntax + * (i.e. with underscores) to avoid future collisions with other macros. + * Provide links to the documentation of each supported compiler, if it exists. + */ + +/* + * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17. + * In the meantime, to support 4.6 <= gcc < 5, we implement __has_attribute + * by hand. + * + * sparse does not support __has_attribute (yet) and defines __GNUC_MINOR__ + * depending on the compiler used to build it; however, these attributes have + * no semantic effects for sparse, so it does not matter. Also note that, + * in order to avoid sparse's warnings, even the unsupported ones must be + * defined to 0. + */ +#ifndef __has_attribute +# define __has_attribute(x) __GCC4_has_attribute_##x +# define __GCC4_has_attribute___assume_aligned__ (__GNUC_MINOR__ >= 9) +# define __GCC4_has_attribute___copy__ 0 +# define __GCC4_has_attribute___designated_init__ 0 +# define __GCC4_has_attribute___externally_visible__ 1 +# define __GCC4_has_attribute___noclone__ 1 +# define __GCC4_has_attribute___nonstring__ 0 +# define __GCC4_has_attribute___no_sanitize_address__ (__GNUC_MINOR__ >= 8) +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute + */ +#define __alias(symbol) __attribute__((__alias__(#symbol))) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-aligned-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-aligned-variable-attribute + */ +#define __aligned(x) __attribute__((__aligned__(x))) +#define __aligned_largest __attribute__((__aligned__)) + +/* + * Note: users of __always_inline currently do not write "inline" themselves, + * which seems to be required by gcc to apply the attribute according + * to its docs (and also "warning: always_inline function might not be + * inlinable [-Wattributes]" is emitted). + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-always_005finline-function-attribute + * clang: mentioned + */ +#define __always_inline inline __attribute__((__always_inline__)) + +/* + * The second argument is optional (default 0), so we use a variadic macro + * to make the shorthand. + * + * Beware: Do not apply this to functions which may return + * ERR_PTRs. Also, it is probably unwise to apply it to functions + * returning extra information in the low bits (but in that case the + * compiler should see some alignment anyway, when the return value is + * massaged by 'flags = ptr & 3; ptr &= ~3;'). + * + * Optional: only supported since gcc >= 4.9 + * Optional: not supported by icc + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#assume-aligned + */ +#if __has_attribute(__assume_aligned__) +# define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__))) +#else +# define __assume_aligned(a, ...) +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-cold-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-cold-label-attribute + */ +#define __cold __attribute__((__cold__)) + +/* + * Note the long name. + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-const-function-attribute + */ +#define __attribute_const__ __attribute__((__const__)) + +/* + * Optional: only supported since gcc >= 9 + * Optional: not supported by clang + * Optional: not supported by icc + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-copy-function-attribute + */ +#if __has_attribute(__copy__) +# define __copy(symbol) __attribute__((__copy__(symbol))) +#else +# define __copy(symbol) +#endif + +/* + * Don't. Just don't. See commit 771c035372a0 ("deprecate the '__deprecated' + * attribute warnings entirely and for good") for more information. + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-deprecated-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-deprecated-type-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-deprecated-variable-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Enumerator-Attributes.html#index-deprecated-enumerator-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#deprecated + */ +#define __deprecated + +/* + * Optional: only supported since gcc >= 5.1 + * Optional: not supported by clang + * Optional: not supported by icc + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-designated_005finit-type-attribute + */ +#if __has_attribute(__designated_init__) +# define __designated_init __attribute__((__designated_init__)) +#else +# define __designated_init +#endif + +/* + * Optional: not supported by clang + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-externally_005fvisible-function-attribute + */ +#if __has_attribute(__externally_visible__) +# define __visible __attribute__((__externally_visible__)) +#else +# define __visible +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-format-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#format + */ +#define __printf(a, b) __attribute__((__format__(printf, a, b))) +#define __scanf(a, b) __attribute__((__format__(scanf, a, b))) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-gnu_005finline-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#gnu-inline + */ +#define __gnu_inline __attribute__((__gnu_inline__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-malloc-function-attribute + */ +#define __malloc __attribute__((__malloc__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-mode-type-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-mode-variable-attribute + */ +#define __mode(x) __attribute__((__mode__(x))) + +/* + * Optional: not supported by clang + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noclone-function-attribute + */ +#if __has_attribute(__noclone__) +# define __noclone __attribute__((__noclone__)) +#else +# define __noclone +#endif + +/* + * Note the missing underscores. + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute + * clang: mentioned + */ +#define noinline __attribute__((__noinline__)) + +/* + * Optional: only supported since gcc >= 8 + * Optional: not supported by clang + * Optional: not supported by icc + * + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute + */ +#if __has_attribute(__nonstring__) +# define __nonstring __attribute__((__nonstring__)) +#else +# define __nonstring +#endif + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noreturn-function-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#noreturn + * clang: https://clang.llvm.org/docs/AttributeReference.html#id1 + */ +#define __noreturn __attribute__((__noreturn__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute + * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute + */ +#define __packed __attribute__((__packed__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute + */ +#define __pure __attribute__((__pure__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-section-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-section-variable-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#section-declspec-allocate + */ +#define __section(S) __attribute__((__section__(#S))) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-unused-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-unused-type-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-unused-variable-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Label-Attributes.html#index-unused-label-attribute + * clang: https://clang.llvm.org/docs/AttributeReference.html#maybe-unused-unused + */ +#define __always_unused __attribute__((__unused__)) +#define __maybe_unused __attribute__((__unused__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-used-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-used-variable-attribute + */ +#define __used __attribute__((__used__)) + +/* + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-weak-function-attribute + * gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-weak-variable-attribute + */ +#define __weak __attribute__((__weak__)) + +#endif /* __LINUX_COMPILER_ATTRIBUTES_H */ |