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 # include <linux/compiler-gcc4.h>
  43 #elif __GNUC__ == 3
  44 # include <linux/compiler-gcc3.h>
  45 #elif __GNUC__ == 2
  46 # include <linux/compiler-gcc2.h>
  47 #else
  48 # error Sorry, your compiler is too old/not recognized.
  49 #endif
  50
  51 /* Intel compiler defines __GNUC__. So we will overwrite implementations
  52  * coming from above header files here
  53  */
  54 #ifdef __INTEL_COMPILER
  55 # include <linux/compiler-intel.h>
  56 #endif
  57
  58 /*
  59  * Generic compiler-dependent macros required for kernel
  60  * build go below this comment. Actual compiler/compiler version
  61  * specific implementations come from the above header files
  62  */
  63
  64 #define likely(x)       __builtin_expect(!!(x), 1)
  65 #define unlikely(x)     __builtin_expect(!!(x), 0)
  66
  67 /* Optimization barrier */
  68 #ifndef barrier
  69 # define barrier() __memory_barrier()
  70 #endif
  71
  72 #ifndef RELOC_HIDE
  73 # define RELOC_HIDE(ptr, off)                                   \
  74   ({ unsigned long __ptr;                                       \
  75      __ptr = (unsigned long) (ptr);                             \
  76     (typeof(ptr)) (__ptr + (off)); })
  77 #endif
  78
  79 #endif /* __KERNEL__ */
  80
  81 #endif /* __ASSEMBLY__ */
  82
  83 /*
  84  * Allow us to mark functions as 'deprecated' and have gcc emit a nice
  85  * warning for each use, in hopes of speeding the functions removal.
  86  * Usage is:
  87  *              int __deprecated foo(void)
  88  */
  89 #ifndef __deprecated
  90 # define __deprecated           /* unimplemented */
  91 #endif
  92
  93 #ifdef MODULE
  94 #define __deprecated_for_modules __deprecated
  95 #else
  96 #define __deprecated_for_modules
  97 #endif
  98
  99 #ifndef __must_check
 100 #define __must_check
 101 #endif
 102
 103 /*
 104  * Allow us to avoid 'defined but not used' warnings on functions and data,
 105  * as well as force them to be emitted to the assembly file.
 106  *
 107  * As of gcc 3.3, static functions that are not marked with attribute((used))
 108  * may be elided from the assembly file.  As of gcc 3.3, static data not so
 109  * marked will not be elided, but this may change in a future gcc version.
 110  *
 111  * In prior versions of gcc, such functions and data would be emitted, but
 112  * would be warned about except with attribute((unused)).
 113  */
 114 #ifndef __attribute_used__
 115 # define __attribute_used__     /* unimplemented */
 116 #endif
 117
 118 /*
 119  * From the GCC manual:
 120  *
 121  * Many functions have no effects except the return value and their
 122  * return value depends only on the parameters and/or global
 123  * variables.  Such a function can be subject to common subexpression
 124  * elimination and loop optimization just as an arithmetic operator
 125  * would be.
 126  * [...]
 127  */
 128 #ifndef __attribute_pure__
 129 # define __attribute_pure__     /* unimplemented */
 130 #endif
 131
 132 /*
 133  * From the GCC manual:
 134  *
 135  * Many functions do not examine any values except their arguments,
 136  * and have no effects except the return value.  Basically this is
 137  * just slightly more strict class than the `pure' attribute above,
 138  * since function is not allowed to read global memory.
 139  *
 140  * Note that a function that has pointer arguments and examines the
 141  * data pointed to must _not_ be declared `const'.  Likewise, a
 142  * function that calls a non-`const' function usually must not be
 143  * `const'.  It does not make sense for a `const' function to return
 144  * `void'.
 145  */
 146 #ifndef __attribute_const__
 147 # define __attribute_const__    /* unimplemented */
 148 #endif
 149
 150 #ifndef noinline
 151 #define noinline
 152 #endif
 153
 154 #ifndef __always_inline
 155 #define __always_inline inline
 156 #endif
 157
 158 #endif /* __LINUX_COMPILER_H */