LXR linux/include/linux/compiler.h

   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 __nocast       __attribute__((nocast))
  12# define __iomem        __attribute__((noderef, address_space(2)))
  13# define __acquires(x)  __attribute__((context(x,0,1)))
  14# define __releases(x)  __attribute__((context(x,1,0)))
  15# define __acquire(x)   __context__(x,1)
  16# define __release(x)   __context__(x,-1)
  17# define __cond_lock(x,c)       ((c) ? ({ __acquire(x); 1; }) : 0)
  18extern void __chk_user_ptr(const void __user *);
  19extern void __chk_io_ptr(const void __iomem *);
  20#else
  21# define __user
  22# define __kernel
  23# define __safe
  24# define __force
  25# define __nocast
  26# define __iomem
  27# define __chk_user_ptr(x) (void)0
  28# define __chk_io_ptr(x) (void)0
  29# define __builtin_warning(x, y...) (1)
  30# define __acquires(x)
  31# define __releases(x)
  32# define __acquire(x) (void)0
  33# define __release(x) (void)0
  34# define __cond_lock(x,c) (c)
  35#endif
  36
  37#ifdef __KERNEL__
  38
  39#if __GNUC__ >= 4
  40# include <linux/compiler-gcc4.h>
  41#elif __GNUC__ == 3 && __GNUC_MINOR__ >= 2
  42# include <linux/compiler-gcc3.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 /* __KERNEL__ */
  76
  77#endif /* __ASSEMBLY__ */
  78
  79#ifdef __KERNEL__
  80/*
  81 * Allow us to mark functions as 'deprecated' and have gcc emit a nice
  82 * warning for each use, in hopes of speeding the functions removal.
  83 * Usage is:
  84 *              int __deprecated foo(void)
  85 */
  86#ifndef __deprecated
  87# define __deprecated           /* unimplemented */
  88#endif
  89
  90#ifdef MODULE
  91#define __deprecated_for_modules __deprecated
  92#else
  93#define __deprecated_for_modules
  94#endif
  95
  96#ifndef __must_check
  97#define __must_check
  98#endif
  99
 100#ifndef CONFIG_ENABLE_MUST_CHECK
 101#undef __must_check
 102#define __must_check
 103#endif
 104
 105/*
 106 * Allow us to avoid 'defined but not used' warnings on functions and data,
 107 * as well as force them to be emitted to the assembly file.
 108 *
 109 * As of gcc 3.4, static functions that are not marked with attribute((used))
 110 * may be elided from the assembly file.  As of gcc 3.4, static data not so
 111 * marked will not be elided, but this may change in a future gcc version.
 112 *
 113 * NOTE: Because distributions shipped with a backported unit-at-a-time
 114 * compiler in gcc 3.3, we must define __used to be __attribute__((used))
 115 * for gcc >=3.3 instead of 3.4.
 116 *
 117 * In prior versions of gcc, such functions and data would be emitted, but
 118 * would be warned about except with attribute((unused)).
 119 *
 120 * Mark functions that are referenced only in inline assembly as __used so
 121 * the code is emitted even though it appears to be unreferenced.
 122 */
 123#ifndef __attribute_used__
 124# define __attribute_used__     /* deprecated */
 125#endif
 126
 127#ifndef __used
 128# define __used                 /* unimplemented */
 129#endif
 130
 131#ifndef __maybe_unused
 132# define __maybe_unused         /* unimplemented */
 133#endif
 134
 135/*
 136 * From the GCC manual:
 137 *
 138 * Many functions have no effects except the return value and their
 139 * return value depends only on the parameters and/or global
 140 * variables.  Such a function can be subject to common subexpression
 141 * elimination and loop optimization just as an arithmetic operator
 142 * would be.
 143 * [...]
 144 */
 145#ifndef __attribute_pure__
 146# define __attribute_pure__     /* unimplemented */
 147#endif
 148
 149#ifndef noinline
 150#define noinline
 151#endif
 152
 153#ifndef __always_inline
 154#define __always_inline inline
 155#endif
 156
 157#endif /* __KERNEL__ */
 158
 159/*
 160 * From the GCC manual:
 161 *
 162 * Many functions do not examine any values except their arguments,
 163 * and have no effects except the return value.  Basically this is
 164 * just slightly more strict class than the `pure' attribute above,
 165 * since function is not allowed to read global memory.
 166 *
 167 * Note that a function that has pointer arguments and examines the
 168 * data pointed to must _not_ be declared `const'.  Likewise, a
 169 * function that calls a non-`const' function usually must not be
 170 * `const'.  It does not make sense for a `const' function to return
 171 * `void'.
 172 */
 173#ifndef __attribute_const__
 174# define __attribute_const__    /* unimplemented */
 175#endif
 176
 177#endif /* __LINUX_COMPILER_H */
 178