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(0,1)))
  14 # define __releases(x)  __attribute__((context(1,0)))
  15 # define __acquire(x)   __context__(1)
  16 # define __release(x)   __context__(-1)
  17 # define __cond_lock(x) ((x) ? ({ __context__(1); 1; }) : 0)
  18 extern void __chk_user_ptr(void __user *);
  19 extern void __chk_io_ptr(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) (x)
  35 #endif
  36
  37 #ifdef __KERNEL__
  38
  39 #if __GNUC__ > 4
  40 #error no compiler-gcc.h file for this gcc version
  41 #elif __GNUC__ == 4
  42 #if __GNUC_MINOR__ >= 3
  43 #error kernel 2.6.16 does not support building with gcc >= 4.3
  44 #else
  45 # include <linux/compiler-gcc4.h>
  46 #endif
  47 #elif __GNUC__ == 3
  48 # include <linux/compiler-gcc3.h>
  49 #else
  50 # error Sorry, your compiler is too old/not recognized.
  51 #endif
  52
  53 /* Intel compiler defines __GNUC__. So we will overwrite implementations
  54  * coming from above header files here
  55  */
  56 #ifdef __INTEL_COMPILER
  57 # include <linux/compiler-intel.h>
  58 #endif
  59
  60 /*
  61  * Generic compiler-dependent macros required for kernel
  62  * build go below this comment. Actual compiler/compiler version
  63  * specific implementations come from the above header files
  64  */
  65
  66 #define likely(x)       __builtin_expect(!!(x), 1)
  67 #define unlikely(x)     __builtin_expect(!!(x), 0)
  68
  69 /* Optimization barrier */
  70 #ifndef barrier
  71 # define barrier() __memory_barrier()
  72 #endif
  73
  74 #ifndef RELOC_HIDE
  75 # define RELOC_HIDE(ptr, off)                                   \
  76   ({ unsigned long __ptr;                                       \
  77      __ptr = (unsigned long) (ptr);                             \
  78     (typeof(ptr)) (__ptr + (off)); })
  79 #endif
  80
  81 #endif /* __KERNEL__ */
  82
  83 #endif /* __ASSEMBLY__ */
  84
  85 /*
  86  * Allow us to mark functions as 'deprecated' and have gcc emit a nice
  87  * warning for each use, in hopes of speeding the functions removal.
  88  * Usage is:
  89  *              int __deprecated foo(void)
  90  */
  91 #ifndef __deprecated
  92 # define __deprecated           /* unimplemented */
  93 #endif
  94
  95 #ifdef MODULE
  96 #define __deprecated_for_modules __deprecated
  97 #else
  98 #define __deprecated_for_modules
  99 #endif
 100
 101 #ifndef __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 3.3, static functions that are not marked with attribute((used))
 110  * may be elided from the assembly file.  As of gcc 3.3, static data not so
 111  * marked will not be elided, but this may change in a future gcc version.
 112  *
 113  * In prior versions of gcc, such functions and data would be emitted, but
 114  * would be warned about except with attribute((unused)).
 115  */
 116 #ifndef __attribute_used__
 117 # define __attribute_used__     /* unimplemented */
 118 #endif
 119
 120 /*
 121  * From the GCC manual:
 122  *
 123  * Many functions have no effects except the return value and their
 124  * return value depends only on the parameters and/or global
 125  * variables.  Such a function can be subject to common subexpression
 126  * elimination and loop optimization just as an arithmetic operator
 127  * would be.
 128  * [...]
 129  */
 130 #ifndef __attribute_pure__
 131 # define __attribute_pure__     /* unimplemented */
 132 #endif
 133
 134 /*
 135  * From the GCC manual:
 136  *
 137  * Many functions do not examine any values except their arguments,
 138  * and have no effects except the return value.  Basically this is
 139  * just slightly more strict class than the `pure' attribute above,
 140  * since function is not allowed to read global memory.
 141  *
 142  * Note that a function that has pointer arguments and examines the
 143  * data pointed to must _not_ be declared `const'.  Likewise, a
 144  * function that calls a non-`const' function usually must not be
 145  * `const'.  It does not make sense for a `const' function to return
 146  * `void'.
 147  */
 148 #ifndef __attribute_const__
 149 # define __attribute_const__    /* unimplemented */
 150 #endif
 151
 152 #ifndef noinline
 153 #define noinline
 154 #endif
 155
 156 #ifndef __always_inline
 157 #define __always_inline inline
 158 #endif
 159
 160 #endif /* __LINUX_COMPILER_H */