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- /* 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 */
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