include/compiler.h

   1 // SPDX-License-Identifier: BSD-2-Clause-Patent
   2
   3 #ifndef COMPILER_H_
   4 #define COMPILER_H_
   5
   6 /*
   7  * These are special ones that get our unit tests in trouble with the
   8  * compiler optimizer dropping out tests...
   9  */
  10 #ifdef NONNULL
  11 # undef NONNULL
  12 #endif
  13 #ifdef RETURNS_NONNULL
  14 # undef RETURNS_NONNULL
  15 #endif
  16 #ifdef SHIM_UNIT_TEST
  17 # define NONNULL(first, args...)
  18 # define RETURNS_NONNULL
  19 #else
  20 # define NONNULL(first, args...) __attribute__((__nonnull__(first, ## args)))
  21 #if (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)))
  22 # define RETURNS_NONNULL __attribute__((__returns_nonnull__))
  23 #else
  24 # define RETURNS_NONNULL
  25 #endif
  26 #endif
  27
  28 #ifndef UNUSED
  29 #define UNUSED __attribute__((__unused__))
  30 #endif
  31 #ifndef HIDDEN
  32 #define HIDDEN __attribute__((__visibility__ ("hidden")))
  33 #endif
  34 #ifndef PUBLIC
  35 #define PUBLIC __attribute__((__visibility__ ("default")))
  36 #endif
  37 #ifndef DEPRECATED
  38 #define DEPRECATED __attribute__((__deprecated__))
  39 #endif
  40 #ifndef DESTRUCTOR
  41 #define DESTRUCTOR __attribute__((destructor))
  42 #endif
  43 #ifndef CONSTRUCTOR
  44 #define CONSTRUCTOR __attribute__((constructor))
  45 #endif
  46 #ifndef ALIAS
  47 #define ALIAS(x) __attribute__((weak, alias (#x)))
  48 #endif
  49 #ifndef ALLOCFUNC
  50 #if defined(__COVERITY__)
  51 #define ALLOCFUNC(a, b)
  52 #else
  53 #define ALLOCFUNC(dealloc, dealloc_arg) __attribute__((__malloc__(dealloc, dealloc_arg)))
  54 #endif
  55 #endif
  56 #ifndef PRINTF
  57 #define PRINTF(first, args...) __attribute__((__format__(printf, first, ## args)))
  58 #endif
  59 #ifndef PURE
  60 #define PURE __attribute__((__pure__))
  61 #endif
  62 #ifndef FLATTEN
  63 #define FLATTEN __attribute__((__flatten__))
  64 #endif
  65 #ifndef PACKED
  66 #define PACKED __attribute__((__packed__))
  67 #endif
  68 #ifndef VERSION
  69 #define VERSION(sym, ver) __asm__(".symver " # sym "," # ver)
  70 #endif
  71 #ifndef NORETURN
  72 #define NORETURN __attribute__((__noreturn__))
  73 #endif
  74 #ifndef ALIGNED
  75 #define ALIGNED(n) __attribute__((__aligned__(n)))
  76 #endif
  77 #ifndef CLEANUP_FUNC
  78 #define CLEANUP_FUNC(x) __attribute__((__cleanup__(x)))
  79 #endif
  80 #ifndef USED
  81 #define USED __attribute__((__used__))
  82 #endif
  83 #ifndef SECTION
  84 #define SECTION(x) __attribute__((__section__(x)))
  85 #endif
  86 #ifndef OPTIMIZE
  87 #define OPTIMIZE(x) __attribute__((__optimize__(x)))
  88 #endif
  89
  90 #ifndef __CONCAT
  91 #define __CONCAT(a, b) a ## b
  92 #endif
  93 #ifndef __CONCAT3
  94 #define __CONCAT3(a, b, c) a ## b ## c
  95 #endif
  96 #ifndef CAT
  97 #define CAT(a, b) __CONCAT(a, b)
  98 #endif
  99 #ifndef CAT3
 100 #define CAT3(a, b, c) __CONCAT3(a, b, c)
 101 #endif
 102 #ifndef STRING
 103 #define STRING(x) __STRING(x)
 104 #endif
 105
 106 #ifndef WRITE_ONCE
 107 #define WRITE_ONCE(var, val) \
 108         (*((volatile typeof(val) *)(&(var))) = (val))
 109 #endif
 110
 111 #ifndef READ_ONCE
 112 #define READ_ONCE(var) (*((volatile typeof(var) *)(&(var))))
 113 #endif
 114
 115 #ifndef likely
 116 #define likely(x)       __builtin_expect(!!(x), 1)
 117 #endif
 118
 119 #ifndef unlikely
 120 #define unlikely(x)     __builtin_expect(!!(x), 0)
 121 #endif
 122
 123 /* Are two types/vars the same type (ignoring qualifiers)? */
 124 #ifndef __same_type
 125 #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 126 #endif
 127
 128 /* Compile time object size, -1 for unknown */
 129 #ifndef __compiletime_object_size
 130 # define __compiletime_object_size(obj) -1
 131 #endif
 132 #ifndef __compiletime_warning
 133 # define __compiletime_warning(message)
 134 #endif
 135 #ifndef __compiletime_error
 136 # define __compiletime_error(message)
 137 #endif
 138
 139 #ifndef __compiletime_assert
 140 #define __compiletime_assert(condition, msg, prefix, suffix)            \
 141         do {                                                            \
 142                 extern void prefix ## suffix(void) __compiletime_error(msg); \
 143                 if (!(condition))                                       \
 144                         prefix ## suffix();                             \
 145         } while (0)
 146 #endif
 147
 148 #ifndef _compiletime_assert
 149 #define _compiletime_assert(condition, msg, prefix, suffix) \
 150         __compiletime_assert(condition, msg, prefix, suffix)
 151 #endif
 152
 153 /**
 154  * compiletime_assert - break build and emit msg if condition is false
 155  * @condition: a compile-time constant condition to check
 156  * @msg:       a message to emit if condition is false
 157  *
 158  * In tradition of POSIX assert, this macro will break the build if the
 159  * supplied condition is *false*, emitting the supplied error message if the
 160  * compiler has support to do so.
 161  */
 162 #ifndef compiletime_assert
 163 #define compiletime_assert(condition, msg) \
 164         _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__ - 1)
 165 #endif
 166
 167 /**
 168  * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
 169  *                    error message.
 170  * @condition: the condition which the compiler should know is false.
 171  *
 172  * See BUILD_BUG_ON for description.
 173  */
 174 #ifndef BUILD_BUG_ON_MSG
 175 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
 176 #endif
 177
 178 #ifndef ALIGN
 179 #define __ALIGN_MASK(x, mask)   (((x) + (mask)) & ~(mask))
 180 #define __ALIGN(x, a)           __ALIGN_MASK(x, (typeof(x))(a) - 1)
 181 #define ALIGN(x, a)             __ALIGN((x), (a))
 182 #endif
 183 #ifndef ALIGN_DOWN
 184 #define ALIGN_DOWN(x, a)        __ALIGN((x) - ((a) - 1), (a))
 185 #endif
 186
 187 #define MIN(a, b) ({(a) < (b) ? (a) : (b);})
 188 #define MAX(a, b) ({(a) <= (b) ? (b) : (a);})
 189
 190 /**
 191  * Builtins that don't go in string.h
 192  */
 193 #define unreachable() __builtin_unreachable()
 194
 195 #endif /* !COMPILER_H_ */
 196 // vim:fenc=utf-8:tw=75:et