1 dnl Macros to check the presence of generic (non-typed) symbols.
2 dnl Copyright (c) 2006-2008 Diego Pettenò <flameeyes@gmail.com>
3 dnl Copyright (c) 2006-2008 xine project
4 dnl Copyright (c) 2012 Lucas De Marchi <lucas.de.marchi@gmail.com>
6 dnl This program is free software; you can redistribute it and/or modify
7 dnl it under the terms of the GNU General Public License as published by
8 dnl the Free Software Foundation; either version 2, or (at your option)
11 dnl This program is distributed in the hope that it will be useful,
12 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
13 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 dnl GNU General Public License for more details.
16 dnl You should have received a copy of the GNU General Public License
17 dnl along with this program; if not, write to the Free Software
18 dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 dnl As a special exception, the copyright owners of the
22 dnl macro gives unlimited permission to copy, distribute and modify the
23 dnl configure scripts that are the output of Autoconf when processing the
24 dnl Macro. You need not follow the terms of the GNU General Public
25 dnl License when using or distributing such scripts, even though portions
26 dnl of the text of the Macro appear in them. The GNU General Public
27 dnl License (GPL) does govern all other use of the material that
28 dnl constitutes the Autoconf Macro.
30 dnl This special exception to the GPL applies to versions of the
31 dnl Autoconf Macro released by this project. When you make and
32 dnl distribute a modified version of the Autoconf Macro, you may extend
33 dnl this special exception to the GPL to apply to your modified version as
36 dnl Check if FLAG in ENV-VAR is supported by compiler and append it
37 dnl to WHERE-TO-APPEND variable. Note that we invert -Wno-* checks to
38 dnl -W* as gcc cannot test for negated warnings.
39 dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
41 AC_DEFUN([CC_CHECK_FLAG_APPEND], [
42 AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
43 AS_TR_SH([cc_cv_$2_$3]),
44 [eval "AS_TR_SH([cc_save_$2])='${$2}'"
45 eval "AS_TR_SH([$2])='-Werror `echo "$3" | sed 's/^-Wno-/-W/'`'"
46 AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])],
47 [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
48 [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
49 eval "AS_TR_SH([$2])='$cc_save_$2'"])
51 AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
52 [eval "$1='${$1} $3'"])
55 dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
56 AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
58 CC_CHECK_FLAG_APPEND($1, $2, $flag)
62 dnl Check if the flag is supported by linker (cacheable)
63 dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
66 dnl Check if the flag is supported by linker
67 dnl CC_CHECK_LDFLAGS_SILENT([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
68 AC_DEFUN([CC_CHECK_LDFLAGS_SILENT], [
69 AC_CACHE_VAL(AS_TR_SH([cc_cv_ldflags_$1]),
70 [ac_save_LDFLAGS="$LDFLAGS"
72 AC_LINK_IFELSE([AC_LANG_SOURCE([int main() { return 1; }])],
73 [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
74 [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
75 LDFLAGS="$ac_save_LDFLAGS"
78 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
82 dnl Check if the flag is supported by linker (cacheable)
83 dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
85 AC_DEFUN([CC_CHECK_LDFLAGS], [
86 AC_CACHE_CHECK([if $CC supports $1 flag],
87 AS_TR_SH([cc_cv_ldflags_$1]),
88 CC_CHECK_LDFLAGS_SILENT([$1]) dnl Don't execute actions here!
91 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
95 dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
96 dnl the current linker to avoid undefined references in a shared object.
97 AC_DEFUN([CC_NOUNDEFINED], [
98 dnl We check $host for which systems to enable this for.
99 AC_REQUIRE([AC_CANONICAL_HOST])
102 dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads
103 dnl are requested, as different implementations are present; to avoid problems
104 dnl use -Wl,-z,defs only for those platform not behaving this way.
105 *-freebsd* | *-openbsd*) ;;
107 dnl First of all check for the --no-undefined variant of GNU ld. This allows
108 dnl for a much more readable command line, so that people can understand what
109 dnl it does without going to look for what the heck -z defs does.
110 for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
111 CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
117 AC_SUBST([LDFLAGS_NOUNDEFINED])
120 dnl Check for a -Werror flag or equivalent. -Werror is the GCC
121 dnl and ICC flag that tells the compiler to treat all the warnings
122 dnl as fatal. We usually need this option to make sure that some
123 dnl constructs (like attributes) are not simply ignored.
125 dnl Other compilers don't support -Werror per se, but they support
126 dnl an equivalent flag:
127 dnl - Sun Studio compiler supports -errwarn=%all
128 AC_DEFUN([CC_CHECK_WERROR], [
130 [for $CC way to treat warnings as errors],
132 [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
133 [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
137 AC_DEFUN([CC_CHECK_ATTRIBUTE], [
138 AC_REQUIRE([CC_CHECK_WERROR])
139 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
140 AS_TR_SH([cc_cv_attribute_$1]),
141 [ac_save_CFLAGS="$CFLAGS"
142 CFLAGS="$CFLAGS $cc_cv_werror"
143 AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
144 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
145 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
146 CFLAGS="$ac_save_CFLAGS"
149 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
151 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
152 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
158 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
161 [void __attribute__((constructor)) ctor() { int a; }],
165 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
167 [format], [format(printf, n, n)],
168 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
172 AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
174 [format_arg], [format_arg(printf)],
175 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
179 AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
181 [visibility_$1], [visibility("$1")],
182 [void __attribute__((visibility("$1"))) $1_function() { }],
186 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
188 [nonnull], [nonnull()],
189 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
193 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
196 [void some_function(void *foo, __attribute__((unused)) void *bar);],
200 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
203 [void some_function(void *foo, ...) __attribute__((sentinel));],
207 AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
210 [void some_function(void *foo, ...) __attribute__((deprecated));],
214 AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
216 [alias], [weak, alias],
217 [void other_function(void *foo) { }
218 void some_function(void *foo) __attribute__((weak, alias("other_function")));],
222 AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
225 [void * __attribute__((malloc)) my_alloc(int n);],
229 AC_DEFUN([CC_ATTRIBUTE_PACKED], [
232 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
236 AC_DEFUN([CC_ATTRIBUTE_CONST], [
239 [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
243 AC_DEFUN([CC_FLAG_VISIBILITY], [
244 AC_REQUIRE([CC_CHECK_WERROR])
245 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
246 [cc_cv_flag_visibility],
247 [cc_flag_visibility_save_CFLAGS="$CFLAGS"
248 CFLAGS="$CFLAGS $cc_cv_werror"
249 CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
250 cc_cv_flag_visibility='yes',
251 cc_cv_flag_visibility='no')
252 CFLAGS="$cc_flag_visibility_save_CFLAGS"])
254 AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
255 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
256 [Define this if the compiler supports the -fvisibility flag])
261 AC_DEFUN([CC_CHECK_FUNC_BUILTIN], [
262 m4_pushdef([UPNAME], m4_translit([$1], [-a-z], [_A-Z]))
263 AC_CACHE_CHECK([if compiler has $1 builtin function],
265 [AC_LINK_IFELSE([AC_LANG_PROGRAM([], [
267 [__builtin_clz], [$1(0)],
268 [__builtin_types_compatible_p], [$1(int, int)],
269 [__builtin_uaddl_overflow], [$1(0UL, 0UL, (void*)0)],
270 [__builtin_uaddll_overflow], [$1(0ULL, 0ULL, (void*)0)],
271 [__builtin_expect], [$1(0, 0)]
274 [cc_cv_have_$1=no])])
276 AS_IF([test "x$cc_cv_have_$1" = "xyes"],
277 [AC_DEFINE([HAVE_]m4_defn([UPNAME]), 1, [Define to 1 if compiler has $1() builtin function])
279 [AS_IF([test "x$3" = "x"], [AC_MSG_ERROR([*** builtin function not found: $1()])],
280 [AC_DEFINE([HAVE_]m4_defn([UPNAME]), 0)
286 AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
287 AC_REQUIRE([CC_CHECK_WERROR])
288 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
289 [cc_cv_attribute_aligned],
290 [ac_save_CFLAGS="$CFLAGS"
291 CFLAGS="$CFLAGS $cc_cv_werror"
292 for cc_attribute_align_try in 64 32 16 8 4 2; do
293 AC_COMPILE_IFELSE([AC_LANG_SOURCE([
295 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
297 }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
299 CFLAGS="$ac_save_CFLAGS"
302 if test "x$cc_cv_attribute_aligned" != "x"; then
303 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
304 [Define the highest alignment supported])