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