include/linux/compiler.h

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