1dnl Macros to check the presence of generic (non-typed) symbols. 2dnl Copyright (c) 2006-2008 Diego Pettenò <flameeyes@gmail.com> 3dnl Copyright (c) 2006-2008 xine project 4dnl Copyright (c) 2012 Lucas De Marchi <lucas.de.marchi@gmail.com> 5dnl 6dnl This program is free software; you can redistribute it and/or modify 7dnl it under the terms of the GNU General Public License as published by 8dnl the Free Software Foundation; either version 2, or (at your option) 9dnl any later version. 10dnl 11dnl This program is distributed in the hope that it will be useful, 12dnl but WITHOUT ANY WARRANTY; without even the implied warranty of 13dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14dnl GNU General Public License for more details. 15dnl 16dnl You should have received a copy of the GNU General Public License 17dnl along with this program; if not, write to the Free Software 18dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19dnl 02110-1301, USA. 20dnl 21dnl As a special exception, the copyright owners of the 22dnl macro gives unlimited permission to copy, distribute and modify the 23dnl configure scripts that are the output of Autoconf when processing the 24dnl Macro. You need not follow the terms of the GNU General Public 25dnl License when using or distributing such scripts, even though portions 26dnl of the text of the Macro appear in them. The GNU General Public 27dnl License (GPL) does govern all other use of the material that 28dnl constitutes the Autoconf Macro. 29dnl 30dnl This special exception to the GPL applies to versions of the 31dnl Autoconf Macro released by this project. When you make and 32dnl distribute a modified version of the Autoconf Macro, you may extend 33dnl this special exception to the GPL to apply to your modified version as 34dnl well. 35 36dnl Check if FLAG in ENV-VAR is supported by compiler and append it 37dnl to WHERE-TO-APPEND variable 38dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG]) 39 40AC_DEFUN([CC_CHECK_FLAG_APPEND], [ 41 AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2], 42 AS_TR_SH([cc_cv_$2_$3]), 43 [eval "AS_TR_SH([cc_save_$2])='${$2}'" 44 eval "AS_TR_SH([$2])='-Werror $3'" 45 AC_LINK_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])], 46 [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"], 47 [eval "AS_TR_SH([cc_cv_$2_$3])='no'"]) 48 eval "AS_TR_SH([$2])='$cc_save_$2'"]) 49 50 AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes], 51 [eval "$1='${$1} $3'"]) 52]) 53 54dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2]) 55AC_DEFUN([CC_CHECK_FLAGS_APPEND], [ 56 for flag in $3; do 57 CC_CHECK_FLAG_APPEND($1, $2, $flag) 58 done 59]) 60 61dnl Check if the flag is supported by linker (cacheable) 62dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND]) 63 64AC_DEFUN([CC_CHECK_LDFLAGS], [ 65 AC_CACHE_CHECK([if $CC supports $1 flag], 66 AS_TR_SH([cc_cv_ldflags_$1]), 67 [ac_save_LDFLAGS="$LDFLAGS" 68 LDFLAGS="$LDFLAGS $1" 69 AC_LINK_IFELSE([int main() { return 1; }], 70 [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"], 71 [eval "AS_TR_SH([cc_cv_ldflags_$1])="]) 72 LDFLAGS="$ac_save_LDFLAGS" 73 ]) 74 75 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes], 76 [$2], [$3]) 77]) 78 79dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for 80dnl the current linker to avoid undefined references in a shared object. 81AC_DEFUN([CC_NOUNDEFINED], [ 82 dnl We check $host for which systems to enable this for. 83 AC_REQUIRE([AC_CANONICAL_HOST]) 84 85 case $host in 86 dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads 87 dnl are requested, as different implementations are present; to avoid problems 88 dnl use -Wl,-z,defs only for those platform not behaving this way. 89 *-freebsd* | *-openbsd*) ;; 90 *) 91 dnl First of all check for the --no-undefined variant of GNU ld. This allows 92 dnl for a much more readable commandline, so that people can understand what 93 dnl it does without going to look for what the heck -z defs does. 94 for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do 95 CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"]) 96 break 97 done 98 ;; 99 esac 100 101 AC_SUBST([LDFLAGS_NOUNDEFINED]) 102]) 103 104dnl Check for a -Werror flag or equivalent. -Werror is the GCC 105dnl and ICC flag that tells the compiler to treat all the warnings 106dnl as fatal. We usually need this option to make sure that some 107dnl constructs (like attributes) are not simply ignored. 108dnl 109dnl Other compilers don't support -Werror per se, but they support 110dnl an equivalent flag: 111dnl - Sun Studio compiler supports -errwarn=%all 112dnl we don't test for that, it gives us false positives when gcc doesn't 113dnl actually complain about it. If someone wants to compile this on sun, let 114dnl them fix it. 115AC_DEFUN([CC_CHECK_WERROR], [ 116 AC_CACHE_CHECK( 117 [for $CC way to treat warnings as errors], 118 [cc_cv_werror], 119 [CC_CHECK_FLAG_APPEND([cc_cv_werror], [CFLAGS], [-Werror])]) 120]) 121 122AC_DEFUN([CC_CHECK_ATTRIBUTE], [ 123 AC_REQUIRE([CC_CHECK_WERROR]) 124 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))], 125 AS_TR_SH([cc_cv_attribute_$1]), 126 [ac_save_CFLAGS="$CFLAGS" 127 CFLAGS="$CFLAGS $cc_cv_werror" 128 AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])], 129 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"], 130 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"]) 131 CFLAGS="$ac_save_CFLAGS" 132 ]) 133 134 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes], 135 [AC_DEFINE( 136 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1, 137 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))] 138 ) 139 $4], 140 [$5]) 141]) 142 143AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [ 144 CC_CHECK_ATTRIBUTE( 145 [constructor],, 146 [void __attribute__((constructor)) ctor() { int a; }], 147 [$1], [$2]) 148]) 149 150AC_DEFUN([CC_ATTRIBUTE_FORMAT], [ 151 CC_CHECK_ATTRIBUTE( 152 [format], [format(printf, n, n)], 153 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }], 154 [$1], [$2]) 155]) 156 157AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [ 158 CC_CHECK_ATTRIBUTE( 159 [format_arg], [format_arg(printf)], 160 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }], 161 [$1], [$2]) 162]) 163 164AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [ 165 CC_CHECK_ATTRIBUTE( 166 [visibility_$1], [visibility("$1")], 167 [void __attribute__((visibility("$1"))) $1_function() { }], 168 [$2], [$3]) 169]) 170 171AC_DEFUN([CC_ATTRIBUTE_NONNULL], [ 172 CC_CHECK_ATTRIBUTE( 173 [nonnull], [nonnull()], 174 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }], 175 [$1], [$2]) 176]) 177 178AC_DEFUN([CC_ATTRIBUTE_UNUSED], [ 179 CC_CHECK_ATTRIBUTE( 180 [unused], , 181 [void some_function(void *foo, __attribute__((unused)) void *bar);], 182 [$1], [$2]) 183]) 184 185AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [ 186 CC_CHECK_ATTRIBUTE( 187 [sentinel], , 188 [void some_function(void *foo, ...) __attribute__((sentinel));], 189 [$1], [$2]) 190]) 191 192AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [ 193 CC_CHECK_ATTRIBUTE( 194 [deprecated], , 195 [void some_function(void *foo, ...) __attribute__((deprecated));], 196 [$1], [$2]) 197]) 198 199AC_DEFUN([CC_ATTRIBUTE_ALIAS], [ 200 CC_CHECK_ATTRIBUTE( 201 [alias], [weak, alias], 202 [void other_function(void *foo) { } 203 void some_function(void *foo) __attribute__((weak, alias("other_function")));], 204 [$1], [$2]) 205]) 206 207AC_DEFUN([CC_ATTRIBUTE_MALLOC], [ 208 CC_CHECK_ATTRIBUTE( 209 [malloc], , 210 [void * __attribute__((malloc)) my_alloc(int n);], 211 [$1], [$2]) 212]) 213 214AC_DEFUN([CC_ATTRIBUTE_PACKED], [ 215 CC_CHECK_ATTRIBUTE( 216 [packed], , 217 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));], 218 [$1], [$2]) 219]) 220 221AC_DEFUN([CC_ATTRIBUTE_CONST], [ 222 CC_CHECK_ATTRIBUTE( 223 [const], , 224 [int __attribute__((const)) twopow(int n) { return 1 << n; } ], 225 [$1], [$2]) 226]) 227 228AC_DEFUN([CC_FLAG_VISIBILITY], [ 229 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden], 230 [cc_cv_flag_visibility], 231 [CC_CHECK_FLAG_APPEND([cc_cv_flag_visibility], [CFLAGS], [-fvisibility=hidden])]) 232 233 AS_IF([test "x$cc_cv_flag_visibility" != "x"], 234 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1, 235 [Define this if the compiler supports the -fvisibility flag]) 236 $1], 237 [$2]) 238]) 239 240AC_DEFUN([CC_FUNC_EXPECT], [ 241 AC_REQUIRE([CC_CHECK_WERROR]) 242 AC_CACHE_CHECK([if compiler has __builtin_expect function], 243 [cc_cv_func_expect], 244 [ac_save_CFLAGS="$CFLAGS" 245 CFLAGS="$CFLAGS $cc_cv_werror" 246 AC_COMPILE_IFELSE([AC_LANG_SOURCE( 247 [int some_function() { 248 int a = 3; 249 return (int)__builtin_expect(a, 3); 250 }])], 251 [cc_cv_func_expect=yes], 252 [cc_cv_func_expect=no]) 253 CFLAGS="$ac_save_CFLAGS" 254 ]) 255 256 AS_IF([test "x$cc_cv_func_expect" = "xyes"], 257 [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1, 258 [Define this if the compiler supports __builtin_expect() function]) 259 $1], 260 [$2]) 261]) 262 263AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [ 264 AC_REQUIRE([CC_CHECK_WERROR]) 265 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported], 266 [cc_cv_attribute_aligned], 267 [ac_save_CFLAGS="$CFLAGS" 268 CFLAGS="$CFLAGS $cc_cv_werror" 269 for cc_attribute_align_try in 64 32 16 8 4 2; do 270 AC_COMPILE_IFELSE([AC_LANG_SOURCE([ 271 int main() { 272 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0; 273 return c; 274 }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break]) 275 done 276 CFLAGS="$ac_save_CFLAGS" 277 ]) 278 279 if test "x$cc_cv_attribute_aligned" != "x"; then 280 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned], 281 [Define the highest alignment supported]) 282 fi 283]) 284