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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_COMPILE_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
112AC_DEFUN([CC_CHECK_WERROR], [
113 AC_CACHE_CHECK(
114 [for $CC way to treat warnings as errors],
115 [cc_cv_werror],
116 [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
117 [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
118 ])
119])
120
121AC_DEFUN([CC_CHECK_ATTRIBUTE], [
122 AC_REQUIRE([CC_CHECK_WERROR])
123 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
124 AS_TR_SH([cc_cv_attribute_$1]),
125 [ac_save_CFLAGS="$CFLAGS"
126 CFLAGS="$CFLAGS $cc_cv_werror"
127 AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
128 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
129 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
130 CFLAGS="$ac_save_CFLAGS"
131 ])
132
133 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
134 [AC_DEFINE(
135 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
136 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
137 )
138 $4],
139 [$5])
140])
141
142AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
143 CC_CHECK_ATTRIBUTE(
144 [constructor],,
145 [void __attribute__((constructor)) ctor() { int a; }],
146 [$1], [$2])
147])
148
149AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
150 CC_CHECK_ATTRIBUTE(
151 [format], [format(printf, n, n)],
152 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
153 [$1], [$2])
154])
155
156AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
157 CC_CHECK_ATTRIBUTE(
158 [format_arg], [format_arg(printf)],
159 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
160 [$1], [$2])
161])
162
163AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
164 CC_CHECK_ATTRIBUTE(
165 [visibility_$1], [visibility("$1")],
166 [void __attribute__((visibility("$1"))) $1_function() { }],
167 [$2], [$3])
168])
169
170AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
171 CC_CHECK_ATTRIBUTE(
172 [nonnull], [nonnull()],
173 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
174 [$1], [$2])
175])
176
177AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
178 CC_CHECK_ATTRIBUTE(
179 [unused], ,
180 [void some_function(void *foo, __attribute__((unused)) void *bar);],
181 [$1], [$2])
182])
183
184AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
185 CC_CHECK_ATTRIBUTE(
186 [sentinel], ,
187 [void some_function(void *foo, ...) __attribute__((sentinel));],
188 [$1], [$2])
189])
190
191AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
192 CC_CHECK_ATTRIBUTE(
193 [deprecated], ,
194 [void some_function(void *foo, ...) __attribute__((deprecated));],
195 [$1], [$2])
196])
197
198AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
199 CC_CHECK_ATTRIBUTE(
200 [alias], [weak, alias],
201 [void other_function(void *foo) { }
202 void some_function(void *foo) __attribute__((weak, alias("other_function")));],
203 [$1], [$2])
204])
205
206AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
207 CC_CHECK_ATTRIBUTE(
208 [malloc], ,
209 [void * __attribute__((malloc)) my_alloc(int n);],
210 [$1], [$2])
211])
212
213AC_DEFUN([CC_ATTRIBUTE_PACKED], [
214 CC_CHECK_ATTRIBUTE(
215 [packed], ,
216 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
217 [$1], [$2])
218])
219
220AC_DEFUN([CC_ATTRIBUTE_CONST], [
221 CC_CHECK_ATTRIBUTE(
222 [const], ,
223 [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
224 [$1], [$2])
225])
226
227AC_DEFUN([CC_FLAG_VISIBILITY], [
228 AC_REQUIRE([CC_CHECK_WERROR])
229 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
230 [cc_cv_flag_visibility],
231 [cc_flag_visibility_save_CFLAGS="$CFLAGS"
232 CFLAGS="$CFLAGS $cc_cv_werror"
233 CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
234 cc_cv_flag_visibility='yes',
235 cc_cv_flag_visibility='no')
236 CFLAGS="$cc_flag_visibility_save_CFLAGS"])
237
238 AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
239 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
240 [Define this if the compiler supports the -fvisibility flag])
241 $1],
242 [$2])
243])
244
245AC_DEFUN([CC_FUNC_EXPECT], [
246 AC_REQUIRE([CC_CHECK_WERROR])
247 AC_CACHE_CHECK([if compiler has __builtin_expect function],
248 [cc_cv_func_expect],
249 [ac_save_CFLAGS="$CFLAGS"
250 CFLAGS="$CFLAGS $cc_cv_werror"
251 AC_COMPILE_IFELSE([AC_LANG_SOURCE(
252 [int some_function() {
253 int a = 3;
254 return (int)__builtin_expect(a, 3);
255 }])],
256 [cc_cv_func_expect=yes],
257 [cc_cv_func_expect=no])
258 CFLAGS="$ac_save_CFLAGS"
259 ])
260
261 AS_IF([test "x$cc_cv_func_expect" = "xyes"],
262 [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
263 [Define this if the compiler supports __builtin_expect() function])
264 $1],
265 [$2])
266])
267
268AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
269 AC_REQUIRE([CC_CHECK_WERROR])
270 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
271 [cc_cv_attribute_aligned],
272 [ac_save_CFLAGS="$CFLAGS"
273 CFLAGS="$CFLAGS $cc_cv_werror"
274 for cc_attribute_align_try in 64 32 16 8 4 2; do
275 AC_COMPILE_IFELSE([AC_LANG_SOURCE([
276 int main() {
277 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
278 return c;
279 }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
280 done
281 CFLAGS="$ac_save_CFLAGS"
282 ])
283
284 if test "x$cc_cv_attribute_aligned" != "x"; then
285 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
286 [Define the highest alignment supported])
287 fi
288])