src/Compiler.h

   1 /*
   2  * Copyright (C) 2003-2013 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef COMPILER_H
  21 #define COMPILER_H
  22
  23 #define GCC_MAKE_VERSION(major, minor, patchlevel) ((major) * 10000 + (minor) * 100 + patchlevel)
  24
  25 #ifdef __GNUC__
  26 #  define GCC_VERSION GCC_MAKE_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
  27 #else
  28 #  define GCC_VERSION 0
  29 #endif
  30
  31 #ifdef __clang__
  32 #  define CLANG_VERSION GCC_MAKE_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__)
  33 #else
  34 #  define CLANG_VERSION 0
  35 #endif
  36
  37 /**
  38  * Are we building with the specified version of gcc (not clang or any
  39  * other compiler) or newer?
  40  */
  41 #define GCC_CHECK_VERSION(major, minor) \
  42   (!CLANG_VERSION && \
  43    GCC_VERSION >= GCC_MAKE_VERSION(major, minor, 0))
  44
  45 /**
  46  * Are we building with clang (any version) or at least the specified
  47  * gcc version?
  48  */
  49 #define CLANG_OR_GCC_VERSION(major, minor) \
  50   (CLANG_VERSION || GCC_CHECK_VERSION(major, minor))
  51
  52 /**
  53  * Are we building with gcc (not clang or any other compiler) and a
  54  * version older than the specified one?
  55  */
  56 #define GCC_OLDER_THAN(major, minor) \
  57   (GCC_VERSION && !CLANG_VERSION && \
  58    GCC_VERSION < GCC_MAKE_VERSION(major, minor, 0))
  59
  60 #if CLANG_OR_GCC_VERSION(4,0)
  61
  62 /* GCC 4.x */
  63
  64 #define gcc_const __attribute__((const))
  65 #define gcc_deprecated __attribute__((deprecated))
  66 #define gcc_may_alias __attribute__((may_alias))
  67 #define gcc_malloc __attribute__((malloc))
  68 #define gcc_noreturn __attribute__((noreturn))
  69 #define gcc_packed __attribute__((packed))
  70 #define gcc_printf(a,b) __attribute__((format(printf, a, b)))
  71 #define gcc_pure __attribute__((pure))
  72 #define gcc_sentinel __attribute__((sentinel))
  73 #define gcc_unused __attribute__((unused))
  74 #define gcc_warn_unused_result __attribute__((warn_unused_result))
  75
  76 #define gcc_nonnull(...) __attribute__((nonnull(__VA_ARGS__)))
  77 #define gcc_nonnull_all __attribute__((nonnull))
  78
  79 #define gcc_likely(x) __builtin_expect (!!(x), 1)
  80 #define gcc_unlikely(x) __builtin_expect (!!(x), 0)
  81
  82 #define gcc_aligned(n) __attribute__((aligned(n)))
  83
  84 #define gcc_visibility_hidden __attribute__((visibility("hidden")))
  85 #define gcc_visibility_default __attribute__((visibility("default")))
  86
  87 #define gcc_always_inline __attribute__((always_inline))
  88
  89 #else
  90
  91 /* generic C compiler */
  92
  93 #define gcc_const
  94 #define gcc_deprecated
  95 #define gcc_may_alias
  96 #define gcc_malloc
  97 #define gcc_noreturn
  98 #define gcc_packed
  99 #define gcc_printf(a,b)
 100 #define gcc_pure
 101 #define gcc_sentinel
 102 #define gcc_unused
 103 #define gcc_warn_unused_result
 104
 105 #define gcc_nonnull(...)
 106 #define gcc_nonnull_all
 107
 108 #define gcc_likely(x) (x)
 109 #define gcc_unlikely(x) (x)
 110
 111 #define gcc_aligned(n)
 112
 113 #define gcc_visibility_hidden
 114 #define gcc_visibility_default
 115
 116 #define gcc_always_inline inline
 117
 118 #endif
 119
 120 #if CLANG_OR_GCC_VERSION(4,3)
 121
 122 #define gcc_hot __attribute__((hot))
 123 #define gcc_cold __attribute__((cold))
 124
 125 #else /* ! GCC_UNUSED >= 40300 */
 126
 127 #define gcc_hot
 128 #define gcc_cold
 129
 130 #endif /* ! GCC_UNUSED >= 40300 */
 131
 132 #if GCC_CHECK_VERSION(4,6)
 133 #define gcc_flatten __attribute__((flatten))
 134 #else
 135 #define gcc_flatten
 136 #endif
 137
 138 #ifndef __cplusplus
 139 /* plain C99 has "restrict" */
 140 #define gcc_restrict restrict
 141 #elif CLANG_OR_GCC_VERSION(4,0)
 142 /* "__restrict__" is a GCC extension for C++ */
 143 #define gcc_restrict __restrict__
 144 #else
 145 /* disable it on other compilers */
 146 #define gcc_restrict
 147 #endif
 148
 149 /* C++11 features */
 150
 151 #if defined(__cplusplus)
 152
 153 /* support for C++11 "override" was added in gcc 4.7 */
 154 #if GCC_OLDER_THAN(4,7)
 155 #define override
 156 #define final
 157 #endif
 158
 159 #if CLANG_OR_GCC_VERSION(4,8)
 160 #define gcc_alignas(T, fallback) alignas(T)
 161 #else
 162 #define gcc_alignas(T, fallback) gcc_aligned(fallback)
 163 #endif
 164
 165 #endif
 166
 167 #ifndef __has_feature
 168   // define dummy macro for non-clang compilers
 169   #define __has_feature(x) 0
 170 #endif
 171
 172 #if __has_feature(attribute_unused_on_fields)
 173 #define gcc_unused_field gcc_unused
 174 #else
 175 #define gcc_unused_field
 176 #endif
 177
 178 #if defined(__GNUC__) || defined(__clang__)
 179 #define gcc_unreachable() __builtin_unreachable()
 180 #else
 181 #define gcc_unreachable()
 182 #endif
 183
 184 #endif