os/base.h

   1 /* Copyright (c) 2012 Apple Inc. All rights reserved.
   2  *
   3  * @APPLE_LICENSE_HEADER_START@
   4  *
   5  * This file contains Original Code and/or Modifications of Original Code
   6  * as defined in and that are subject to the Apple Public Source License
   7  * Version 2.0 (the 'License'). You may not use this file except in
   8  * compliance with the License. Please obtain a copy of the License at
   9  * http://www.opensource.apple.com/apsl/ and read it before using this
  10  * file.
  11  *
  12  * The Original Code and all software distributed under the License are
  13  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  17  * Please see the License for the specific language governing rights and
  18  * limitations under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 #ifndef __OS_BASE_H__
  24 #define __OS_BASE_H__
  25
  26 #if __GNUC__
  27 #define os_fastpath(x) ((__typeof__(x))(uintptr_t)__builtin_expect((uintptr_t)(x), ~0l))
  28 #define os_slowpath(x) ((__typeof__(x))(uintptr_t)__builtin_expect((uintptr_t)(x), 0l))
  29 #define os_constant(x) __builtin_constant_p((x))
  30 #define os_hardware_trap() __asm__ __volatile__ (""); __builtin_trap()
  31
  32 #define __OS_COMPILETIME_ASSERT__(e) __extension__({ \
  33         char __compile_time_assert__[(e) ? 1 : -1];     \
  34         (void)__compile_time_assert__; \
  35 })
  36
  37 #define __OS_CONST __attribute__((__const__))
  38 #define __OS_PRINTFLIKE(x,y) __attribute__((__format__(printf,x,y)))
  39 #else /* __GNUC__ */
  40 #define os_fastpath(x) (x)
  41 #define os_slowpath(x) (x)
  42 #define os_constant(x) ((long)0)
  43 #define os_hardware_trap() abort()
  44
  45 #define __OS_COMPILETIME_ASSERT__(e) (e)
  46
  47 #define __OS_CONST
  48 #define __OS_PRINTFLIKE(x,y)
  49 #endif /* __GNUC__ */
  50
  51 #endif /* __OS_BASE_H__ */