1 # =========================================================================== 2 # http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html 3 # =========================================================================== 4 # 5 # SYNOPSIS 6 # 7 # AX_GCC_FUNC_ATTRIBUTE(ATTRIBUTE) 8 # 9 # DESCRIPTION 10 # 11 # This macro checks if the compiler supports one of GCC's function 12 # attributes; many other compilers also provide function attributes with 13 # the same syntax. Compiler warnings are used to detect supported 14 # attributes as unsupported ones are ignored by default so quieting 15 # warnings when using this macro will yield false positives. 16 # 17 # The ATTRIBUTE parameter holds the name of the attribute to be checked. 18 # 19 # If ATTRIBUTE is supported define HAVE_FUNC_ATTRIBUTE_<ATTRIBUTE>. 20 # 21 # The macro caches its result in the ax_cv_have_func_attribute_<attribute> 22 # variable. 23 # 24 # The macro currently supports the following function attributes: 25 # 26 # alias 27 # aligned 28 # alloc_size 29 # always_inline 30 # artificial 31 # cold 32 # const 33 # constructor 34 # deprecated 35 # destructor 36 # dllexport 37 # dllimport 38 # error 39 # externally_visible 40 # flatten 41 # format 42 # format_arg 43 # gnu_inline 44 # hot 45 # ifunc 46 # leaf 47 # malloc 48 # noclone 49 # noinline 50 # nonnull 51 # noreturn 52 # nothrow 53 # optimize 54 # packed 55 # pure 56 # returns_nonnull 57 # unused 58 # used 59 # visibility 60 # warning 61 # warn_unused_result 62 # weak 63 # weakref 64 # 65 # Unsuppored function attributes will be tested with a prototype returning 66 # an int and not accepting any arguments and the result of the check might 67 # be wrong or meaningless so use with care. 68 # 69 # LICENSE 70 # 71 # Copyright (c) 2013 Gabriele Svelto <gabriele.svelto (a] gmail.com> 72 # 73 # Copying and distribution of this file, with or without modification, are 74 # permitted in any medium without royalty provided the copyright notice 75 # and this notice are preserved. This file is offered as-is, without any 76 # warranty. 77 78 #serial 2 79 80 # mattst88: 81 # Added support for returns_nonnull attribute 82 83 AC_DEFUN([AX_GCC_FUNC_ATTRIBUTE], [ 84 AS_VAR_PUSHDEF([ac_var], [ax_cv_have_func_attribute_$1]) 85 86 AC_CACHE_CHECK([for __attribute__(($1))], [ac_var], [ 87 AC_LINK_IFELSE([AC_LANG_PROGRAM([ 88 m4_case([$1], 89 [alias], [ 90 int foo( void ) { return 0; } 91 int bar( void ) __attribute__(($1("foo"))); 92 ], 93 [aligned], [ 94 int foo( void ) __attribute__(($1(32))); 95 ], 96 [alloc_size], [ 97 void *foo(int a) __attribute__(($1(1))); 98 ], 99 [always_inline], [ 100 inline __attribute__(($1)) int foo( void ) { return 0; } 101 ], 102 [artificial], [ 103 inline __attribute__(($1)) int foo( void ) { return 0; } 104 ], 105 [cold], [ 106 int foo( void ) __attribute__(($1)); 107 ], 108 [const], [ 109 int foo( void ) __attribute__(($1)); 110 ], 111 [constructor], [ 112 int foo( void ) __attribute__(($1)); 113 ], 114 [deprecated], [ 115 int foo( void ) __attribute__(($1(""))); 116 ], 117 [destructor], [ 118 int foo( void ) __attribute__(($1)); 119 ], 120 [dllexport], [ 121 __attribute__(($1)) int foo( void ) { return 0; } 122 ], 123 [dllimport], [ 124 int foo( void ) __attribute__(($1)); 125 ], 126 [error], [ 127 int foo( void ) __attribute__(($1(""))); 128 ], 129 [externally_visible], [ 130 int foo( void ) __attribute__(($1)); 131 ], 132 [flatten], [ 133 int foo( void ) __attribute__(($1)); 134 ], 135 [format], [ 136 int foo(const char *p, ...) __attribute__(($1(printf, 1, 2))); 137 ], 138 [format_arg], [ 139 char *foo(const char *p) __attribute__(($1(1))); 140 ], 141 [gnu_inline], [ 142 inline __attribute__(($1)) int foo( void ) { return 0; } 143 ], 144 [hot], [ 145 int foo( void ) __attribute__(($1)); 146 ], 147 [ifunc], [ 148 int my_foo( void ) { return 0; } 149 static int (*resolve_foo(void))(void) { return my_foo; } 150 int foo( void ) __attribute__(($1("resolve_foo"))); 151 ], 152 [leaf], [ 153 __attribute__(($1)) int foo( void ) { return 0; } 154 ], 155 [malloc], [ 156 void *foo( void ) __attribute__(($1)); 157 ], 158 [noclone], [ 159 int foo( void ) __attribute__(($1)); 160 ], 161 [noinline], [ 162 __attribute__(($1)) int foo( void ) { return 0; } 163 ], 164 [nonnull], [ 165 int foo(char *p) __attribute__(($1(1))); 166 ], 167 [noreturn], [ 168 void foo( void ) __attribute__(($1)); 169 ], 170 [nothrow], [ 171 int foo( void ) __attribute__(($1)); 172 ], 173 [optimize], [ 174 __attribute__(($1(3))) int foo( void ) { return 0; } 175 ], 176 [packed], [ 177 struct __attribute__(($1)) foo { int bar; }; 178 ], 179 [pure], [ 180 int foo( void ) __attribute__(($1)); 181 ], 182 [returns_nonnull], [ 183 int *foo( void ) __attribute__(($1)); 184 ], 185 [unused], [ 186 int foo( void ) __attribute__(($1)); 187 ], 188 [used], [ 189 int foo( void ) __attribute__(($1)); 190 ], 191 [visibility], [ 192 int foo_def( void ) __attribute__(($1("default"))); 193 int foo_hid( void ) __attribute__(($1("hidden"))); 194 int foo_int( void ) __attribute__(($1("internal"))); 195 int foo_pro( void ) __attribute__(($1("protected"))); 196 ], 197 [warning], [ 198 int foo( void ) __attribute__(($1(""))); 199 ], 200 [warn_unused_result], [ 201 int foo( void ) __attribute__(($1)); 202 ], 203 [weak], [ 204 int foo( void ) __attribute__(($1)); 205 ], 206 [weakref], [ 207 static int foo( void ) { return 0; } 208 static int bar( void ) __attribute__(($1("foo"))); 209 ], 210 [ 211 m4_warn([syntax], [Unsupported attribute $1, the test may fail]) 212 int foo( void ) __attribute__(($1)); 213 ] 214 )], []) 215 ], 216 dnl GCC doesn't exit with an error if an unknown attribute is 217 dnl provided but only outputs a warning, so accept the attribute 218 dnl only if no warning were issued. 219 [AS_IF([test -s conftest.err], 220 [AS_VAR_SET([ac_var], [no])], 221 [AS_VAR_SET([ac_var], [yes])])], 222 [AS_VAR_SET([ac_var], [no])]) 223 ]) 224 225 AS_IF([test yes = AS_VAR_GET([ac_var])], 226 [AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_FUNC_ATTRIBUTE_$1), 1, 227 [Define to 1 if the system has the `$1' function attribute])], []) 228 229 AS_VAR_POPDEF([ac_var]) 230 ]) 231
