com32/include/klibc/compiler.h

   1 /*
   2  * klibc/compiler.h
   3  *
   4  * Various compiler features
   5  */
   6
   7 #ifndef _KLIBC_COMPILER_H
   8 #define _KLIBC_COMPILER_H
   9
  10 #define __user
  11
  12 /* Specific calling conventions */
  13 /* __cdecl is used when we want varadic and non-varadic functions to have
  14    the same binary calling convention. */
  15 #ifdef __i386__
  16 # ifdef __GNUC__
  17 #  define __cdecl __attribute__((cdecl,regparm(0)))
  18 # else
  19   /* Most other C compilers have __cdecl as a keyword */
  20 # endif
  21 #else
  22 # define __cdecl                /* Meaningless on non-i386 */
  23 #endif
  24
  25 /* How to declare a function that *must* be inlined */
  26 #ifdef __GNUC__
  27 # if __GNUC_MAJOR__ >= 3
  28 #  define __must_inline static __inline__ __attribute__((always_inline))
  29 # else
  30 #  define __must_inline extern __inline__
  31 # endif
  32 #else
  33 # define __must_inline inline   /* Just hope this works... */
  34 #endif
  35
  36 /* How to declare a function that does not return */
  37 #ifdef __GNUC__
  38 # define __noreturn void __attribute__((noreturn))
  39 #else
  40 # define __noreturn void
  41 #endif
  42
  43 /* "const" function:
  44
  45      Many functions do not examine any values except their arguments,
  46      and have no effects except the return value.  Basically this is
  47      just slightly more strict class than the `pure' attribute above,
  48      since function is not allowed to read global memory.
  49
  50      Note that a function that has pointer arguments and examines the
  51      data pointed to must _not_ be declared `const'.  Likewise, a
  52      function that calls a non-`const' function usually must not be
  53      `const'.  It does not make sense for a `const' function to return
  54      `void'.
  55 */
  56 #ifdef __GNUC__
  57 # define __constfunc __attribute__((const))
  58 #else
  59 # define __constfunc
  60 #endif
  61 #undef __attribute_const__
  62 #define __attribute_const__ __constfunc
  63
  64 /* "pure" function:
  65
  66      Many functions have no effects except the return value and their
  67      return value depends only on the parameters and/or global
  68      variables.  Such a function can be subject to common subexpression
  69      elimination and loop optimization just as an arithmetic operator
  70      would be.  These functions should be declared with the attribute
  71      `pure'.
  72 */
  73 #ifdef __GNUC__
  74 # define __purefunc __attribute__((pure))
  75 #else
  76 # define __purefunc
  77 #endif
  78 #undef __attribute_pure__
  79 #define __attribute_pure__ __purefunc
  80
  81 /* Format attribute */
  82 #ifdef __GNUC__
  83 # define __formatfunc(t,f,a) __attribute__((format(t,f,a)))
  84 #else
  85 # define __formatfunc(t,f,a)
  86 #endif
  87
  88 /* malloc() function (returns unaliased pointer) */
  89 #if defined(__GNUC__) && (__GNUC_MAJOR__ >= 3)
  90 # define __mallocfunc __attribute__((malloc))
  91 #else
  92 # define __mallocfunc
  93 #endif
  94
  95 /* likely/unlikely */
  96 #if defined(__GNUC__) && (__GNUC_MAJOR__ > 2 || (__GNUC_MAJOR__ == 2 && __GNUC_MINOR__ >= 95))
  97 # define __likely(x)   __builtin_expect(!!(x), 1)
  98 # define __unlikely(x) __builtin_expect(!!(x), 0)
  99 #else
 100 # define __likely(x)   (!!(x))
 101 # define __unlikely(x) (!!(x))
 102 #endif
 103
 104 /* Possibly unused function */
 105 #ifdef __GNUC__
 106 # define __unusedfunc   __attribute__((unused))
 107 #else
 108 # define __unusedfunc
 109 #endif
 110
 111 /* Declare a variable or data structure as unused. */
 112 #ifdef __GNUC__
 113 # define __unused       __attribute__((unused))
 114 #else
 115 # define __unused
 116 #endif
 117
 118 /* Used symbol */
 119 #define __used                          __attribute__((used))
 120
 121 /* Constructors and destructors */
 122 #define __constructor   __attribute__((constructor))
 123 #define __destructor    __attribute__((destructor))
 124
 125 /* Packed structures */
 126 #define __packed        __attribute__((packed))
 127
 128 /* Weak symbols */
 129 #define __weak          __attribute__((weak))
 130
 131 /* Alignment */
 132 #define __aligned(x)    __attribute__((aligned(x)))
 133 #define __alignas(x)    __attribute__((aligned(__alignof__(x))))
 134
 135 /* Handling of common (affect constructors/destructors) */
 136 #define __common        __attribute__((common))
 137 #define __nocommon      __attribute__((nocommon))
 138
 139 /* Weak symbols */
 140 #define __weak                  __attribute__((weak))
 141
 142 #define __export                __attribute__((visibility("default")))
 143
 144 #endif