/* 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) # define __GCC4_has_attribute___fallthrough__ 0 #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 /* * Add the pseudo keyword 'fallthrough' so case statement blocks * must end with any of these keywords: * break; * fallthrough; * goto <label>; * return [expression]; * * gcc: https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html#Statement-Attributes */ #if __has_attribute(__fallthrough__) # define fallthrough __attribute__((__fallthrough__)) #else # define fallthrough do {} while (0) /* fallthrough */ #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 */