/* 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.
*/
/*
* 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: do not use this directly. Instead, use __alloc_size() since it is conditionally
* available and includes other attributes.
*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alloc_005fsize-function-attribute
* clang: https://clang.llvm.org/docs/AttributeReference.html#alloc-size
*/
#define __alloc_size__(x, ...) __attribute__((__alloc_size__(x, ## __VA_ARGS__)))
/*
* 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: 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__))
/*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-cleanup-variable-attribute
* clang: https://clang.llvm.org/docs/AttributeReference.html#cleanup
*/
#define __cleanup(func) __attribute__((__cleanup__(func)))
/*
* 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: only supported since clang >= 14.0
*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-error-function-attribute
*/
#if __has_attribute(__error__)
# define __compiletime_error(msg) __attribute__((__error__(msg)))
#else
# define __compiletime_error(msg)
#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
* clang: https://clang.llvm.org/docs/AttributeReference.html#malloc
*/
#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: only supported since gcc >= 7
*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/x86-Function-Attributes.html#index-no_005fcaller_005fsaved_005fregisters-function-attribute_002c-x86
* clang: https://clang.llvm.org/docs/AttributeReference.html#no-caller-saved-registers
*/
#if __has_attribute(__no_caller_saved_registers__)
# define __no_caller_saved_registers __attribute__((__no_caller_saved_registers__))
#else
# define __no_caller_saved_registers
#endif
/*
* 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;
* continue;
* goto