linux/include/linux/compiler.h
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   1#ifndef __LINUX_COMPILER_H
   2#define __LINUX_COMPILER_H
   3
   4#ifndef __ASSEMBLY__
   5
   6#ifdef __CHECKER__
   7# define __user         __attribute__((noderef, address_space(1)))
   8# define __kernel       /* default address space */
   9# define __safe         __attribute__((safe))
  10# define __force        __attribute__((force))
  11# define __iomem        __attribute__((noderef, address_space(2)))
  12# define __acquires(x)  __attribute__((context(0,1)))
  13# define __releases(x)  __attribute__((context(1,0)))
  14# define __acquire(x)   __context__(1)
  15# define __release(x)   __context__(-1)
  16# define __cond_lock(x) ((x) ? ({ __context__(1); 1; }) : 0)
  17extern void __chk_user_ptr(void __user *);
  18extern void __chk_io_ptr(void __iomem *);
  19#else
  20# define __user
  21# define __kernel
  22# define __safe
  23# define __force
  24# define __iomem
  25# define __chk_user_ptr(x) (void)0
  26# define __chk_io_ptr(x) (void)0
  27# define __builtin_warning(x, y...) (1)
  28# define __acquires(x)
  29# define __releases(x)
  30# define __acquire(x) (void)0
  31# define __release(x) (void)0
  32# define __cond_lock(x) (x)
  33#endif
  34
  35#ifdef __KERNEL__
  36
  37#if __GNUC__ > 3
  38# include <linux/compiler-gcc+.h>       /* catch-all for GCC 4, 5, etc. */
  39#elif __GNUC__ == 3
  40# include <linux/compiler-gcc3.h>
  41#elif __GNUC__ == 2
  42# include <linux/compiler-gcc2.h>
  43#else
  44# error Sorry, your compiler is too old/not recognized.
  45#endif
  46
  47/* Intel compiler defines __GNUC__. So we will overwrite implementations
  48 * coming from above header files here
  49 */
  50#ifdef __INTEL_COMPILER
  51# include <linux/compiler-intel.h>
  52#endif
  53
  54/*
  55 * Generic compiler-dependent macros required for kernel
  56 * build go below this comment. Actual compiler/compiler version
  57 * specific implementations come from the above header files
  58 */
  59
  60#define likely(x)       __builtin_expect(!!(x), 1)
  61#define unlikely(x)     __builtin_expect(!!(x), 0)
  62
  63/* Optimization barrier */
  64#ifndef barrier
  65# define barrier() __memory_barrier()
  66#endif
  67
  68#ifndef RELOC_HIDE
  69# define RELOC_HIDE(ptr, off)                                   \
  70  ({ unsigned long __ptr;                                       \
  71     __ptr = (unsigned long) (ptr);                             \
  72    (typeof(ptr)) (__ptr + (off)); })
  73#endif
  74
  75#endif /* __ASSEMBLY__ */
  76
  77#endif /* __KERNEL__ */
  78
  79/*
  80 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
  81 * warning for each use, in hopes of speeding the functions removal.
  82 * Usage is:
  83 *              int __deprecated foo(void)
  84 */
  85#ifndef __deprecated
  86# define __deprecated           /* unimplemented */
  87#endif
  88
  89#ifndef __must_check
  90#define __must_check
  91#endif
  92
  93/*
  94 * Allow us to avoid 'defined but not used' warnings on functions and data,
  95 * as well as force them to be emitted to the assembly file.
  96 *
  97 * As of gcc 3.3, static functions that are not marked with attribute((used))
  98 * may be elided from the assembly file.  As of gcc 3.3, static data not so
  99 * marked will not be elided, but this may change in a future gcc version.
 100 *
 101 * In prior versions of gcc, such functions and data would be emitted, but
 102 * would be warned about except with attribute((unused)).
 103 */
 104#ifndef __attribute_used__
 105# define __attribute_used__     /* unimplemented */
 106#endif
 107
 108/*
 109 * From the GCC manual:
 110 *
 111 * Many functions have no effects except the return value and their
 112 * return value depends only on the parameters and/or global
 113 * variables.  Such a function can be subject to common subexpression
 114 * elimination and loop optimization just as an arithmetic operator
 115 * would be.
 116 * [...]
 117 */
 118#ifndef __attribute_pure__
 119# define __attribute_pure__     /* unimplemented */
 120#endif
 121
 122/*
 123 * From the GCC manual:
 124 *
 125 * Many functions do not examine any values except their arguments,
 126 * and have no effects except the return value.  Basically this is
 127 * just slightly more strict class than the `pure' attribute above,
 128 * since function is not allowed to read global memory.
 129 *
 130 * Note that a function that has pointer arguments and examines the
 131 * data pointed to must _not_ be declared `const'.  Likewise, a
 132 * function that calls a non-`const' function usually must not be
 133 * `const'.  It does not make sense for a `const' function to return
 134 * `void'.
 135 */
 136#ifndef __attribute_const__
 137# define __attribute_const__    /* unimplemented */
 138#endif
 139
 140#ifndef noinline
 141#define noinline
 142#endif
 143
 144#ifndef __always_inline
 145#define __always_inline inline
 146#endif
 147
 148#endif /* __LINUX_COMPILER_H */
 149
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