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alistair23-linux/include/linux/compiler_types.h
Miguel Ojeda a3f8a30f3f Compiler Attributes: use feature checks instead of version checks 
Instead of using version checks per-compiler to define (or not)
each attribute, use __has_attribute to test for them, following
the cleanup started with commit 815f0ddb34
("include/linux/compiler*.h: make compiler-*.h mutually exclusive"),
which 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.

All the attributes that can be unconditionally defined and directly
map to compiler attribute(s) (even if optional) have been moved
to a new file include/linux/compiler_attributes.h

In an effort to make the file as regular as possible, comments
stating the purpose of attributes have been removed. Instead,
links to the compiler docs have been added (i.e. to gcc and,
if available, to clang as well). In addition, they have been sorted.

Finally, if an attribute is optional (i.e. if it is guarded
by __has_attribute), the reason has been stated for future reference.

Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # on top of v4.19-rc5, clang 7
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2018-09-30 20:14:03 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_COMPILER_TYPES_H
#define __LINUX_COMPILER_TYPES_H
#ifndef __ASSEMBLY__
#ifdef __CHECKER__
# define __user __attribute__((noderef, address_space(1)))
# define __kernel __attribute__((address_space(0)))
# define __safe __attribute__((safe))
# define __force __attribute__((force))
# define __nocast __attribute__((nocast))
# define __iomem __attribute__((noderef, address_space(2)))
# define __must_hold(x) __attribute__((context(x,1,1)))
# define __acquires(x) __attribute__((context(x,0,1)))
# define __releases(x) __attribute__((context(x,1,0)))
# define __acquire(x) __context__(x,1)
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
# define __percpu __attribute__((noderef, address_space(3)))
# define __rcu __attribute__((noderef, address_space(4)))
# define __private __attribute__((noderef))
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
#else /* __CHECKER__ */
# ifdef STRUCTLEAK_PLUGIN
# define __user __attribute__((user))
# else
# define __user
# endif
# define __kernel
# define __safe
# define __force
# define __nocast
# define __iomem
# define __chk_user_ptr(x) (void)0
# define __chk_io_ptr(x) (void)0
# define __builtin_warning(x, y...) (1)
# define __must_hold(x)
# define __acquires(x)
# define __releases(x)
# define __acquire(x) (void)0
# define __release(x) (void)0
# define __cond_lock(x,c) (c)
# define __percpu
# define __rcu
# define __private
# define ACCESS_PRIVATE(p, member) ((p)->member)
#endif /* __CHECKER__ */
/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
#define ___PASTE(a,b) a##b
#define __PASTE(a,b) ___PASTE(a,b)
#ifdef __KERNEL__
/* Attributes */
#include <linux/compiler_attributes.h>
/* Compiler specific macros. */
#ifdef __clang__
#include <linux/compiler-clang.h>
#elif defined(__INTEL_COMPILER)
#include <linux/compiler-intel.h>
#elif defined(__GNUC__)
/* The above compilers also define __GNUC__, so order is important here. */
#include <linux/compiler-gcc.h>
#else
#error "Unknown compiler"
#endif
/*
* Some architectures need to provide custom definitions of macros provided
* by linux/compiler-*.h, and can do so using asm/compiler.h. We include that
* conditionally rather than using an asm-generic wrapper in order to avoid
* build failures if any C compilation, which will include this file via an
* -include argument in c_flags, occurs prior to the asm-generic wrappers being
* generated.
*/
#ifdef CONFIG_HAVE_ARCH_COMPILER_H
#include <asm/compiler.h>
#endif
struct ftrace_branch_data {
const char *func;
const char *file;
unsigned line;
union {
struct {
unsigned long correct;
unsigned long incorrect;
};
struct {
unsigned long miss;
unsigned long hit;
};
unsigned long miss_hit[2];
};
};
struct ftrace_likely_data {
struct ftrace_branch_data data;
unsigned long constant;
};
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
/*
* The below symbols may be defined for one or more, but not ALL, of the above
* compilers. We don't consider that to be an error, so set them to nothing.
* For example, some of them are for compiler specific plugins.
*/
#ifndef __latent_entropy
# define __latent_entropy
#endif
#ifndef __randomize_layout
# define __randomize_layout __designated_init
#endif
#ifndef __no_randomize_layout
# define __no_randomize_layout
#endif
#ifndef randomized_struct_fields_start
# define randomized_struct_fields_start
# define randomized_struct_fields_end
#endif
/* Are two types/vars the same type (ignoring qualifiers)? */
#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
/* Is this type a native word size -- useful for atomic operations */
#define __native_word(t) \
(sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || \
sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
/* Helpers for emitting diagnostics in pragmas. */
#ifndef __diag
#define __diag(string)
#endif
#ifndef __diag_GCC
#define __diag_GCC(version, severity, string)
#endif
#define __diag_push() __diag(push)
#define __diag_pop() __diag(pop)
#define __diag_ignore(compiler, version, option, comment) \
__diag_ ## compiler(version, ignore, option)
#define __diag_warn(compiler, version, option, comment) \
__diag_ ## compiler(version, warn, option)
#define __diag_error(compiler, version, option, comment) \
__diag_ ## compiler(version, error, option)
#ifdef CONFIG_ENABLE_MUST_CHECK
#define __must_check __attribute__((__warn_unused_result__))
#else
#define __must_check
#endif
#if defined(CC_USING_HOTPATCH)
#define notrace __attribute__((hotpatch(0, 0)))
#else
#define notrace __attribute__((__no_instrument_function__))
#endif
/*
* it doesn't make sense on ARM (currently the only user of __naked)
* to trace naked functions because then mcount is called without
* stack and frame pointer being set up and there is no chance to
* restore the lr register to the value before mcount was called.
*/
#define __naked __attribute__((__naked__)) notrace
#define __compiler_offsetof(a, b) __builtin_offsetof(a, b)
/*
* Force always-inline if the user requests it so via the .config.
* GCC does not warn about unused static inline functions for
* -Wunused-function. This turns out to avoid the need for complex #ifdef
* directives. Suppress the warning in clang as well by using "unused"
* function attribute, which is redundant but not harmful for gcc.
* Prefer gnu_inline, so that extern inline functions do not emit an
* externally visible function. This makes extern inline behave as per gnu89
* semantics rather than c99. This prevents multiple symbol definition errors
* of extern inline functions at link time.
* A lot of inline functions can cause havoc with function tracing.
* Do not use __always_inline here, since currently it expands to inline again
* (which would break users of __always_inline).
*/
#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
!defined(CONFIG_OPTIMIZE_INLINING)
#define inline inline __attribute__((__always_inline__)) __gnu_inline \
__maybe_unused notrace
#else
#define inline inline __gnu_inline \
__maybe_unused notrace
#endif
#define __inline__ inline
#define __inline inline
/*
* Rather then using noinline to prevent stack consumption, use
* noinline_for_stack instead. For documentation reasons.
*/
#define noinline_for_stack noinline
#endif /* __LINUX_COMPILER_TYPES_H */
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