summaryrefslogtreecommitdiff
path: root/m4/attributes.m4
blob: aa53ef238027826b3f8d2d24fea27cc18c6aee71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
dnl Macros to check the presence of generic (non-typed) symbols.
dnl Copyright (c) 2006-2008 Diego Pettenò <flameeyes@gmail.com>
dnl Copyright (c) 2006-2008 xine project
dnl Copyright (c) 2012 Lucas De Marchi <lucas.de.marchi@gmail.com>
dnl
dnl This program is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU General Public License as published by
dnl the Free Software Foundation; either version 2, or (at your option)
dnl any later version.
dnl
dnl This program is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
dnl GNU General Public License for more details.
dnl
dnl You should have received a copy of the GNU General Public License
dnl along with this program; if not, write to the Free Software
dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
dnl 02110-1301, USA.
dnl
dnl As a special exception, the copyright owners of the
dnl macro gives unlimited permission to copy, distribute and modify the
dnl configure scripts that are the output of Autoconf when processing the
dnl Macro. You need not follow the terms of the GNU General Public
dnl License when using or distributing such scripts, even though portions
dnl of the text of the Macro appear in them. The GNU General Public
dnl License (GPL) does govern all other use of the material that
dnl constitutes the Autoconf Macro.
dnl
dnl This special exception to the GPL applies to versions of the
dnl Autoconf Macro released by this project. When you make and
dnl distribute a modified version of the Autoconf Macro, you may extend
dnl this special exception to the GPL to apply to your modified version as
dnl well.

dnl Check if FLAG in ENV-VAR is supported by compiler and append it
dnl to WHERE-TO-APPEND variable
dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])

AC_DEFUN([CC_CHECK_FLAG_APPEND], [
  AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
                 AS_TR_SH([cc_cv_$2_$3]),
          [eval "AS_TR_SH([cc_save_$2])='${$2}'"
           eval "AS_TR_SH([$2])='-Werror $3'"
           AC_LINK_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
                          [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
                          [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
           eval "AS_TR_SH([$2])='$cc_save_$2'"])

  AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
        [eval "$1='${$1} $3'"])
])

dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
  for flag in $3; do
    CC_CHECK_FLAG_APPEND($1, $2, $flag)
  done
])

dnl Check if the flag is supported by linker (cacheable)
dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])

AC_DEFUN([CC_CHECK_LDFLAGS], [
  AC_CACHE_CHECK([if $CC supports $1 flag],
    AS_TR_SH([cc_cv_ldflags_$1]),
    [ac_save_LDFLAGS="$LDFLAGS"
     LDFLAGS="$LDFLAGS $1"
     AC_LINK_IFELSE([int main() { return 1; }],
       [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
       [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
     LDFLAGS="$ac_save_LDFLAGS"
    ])

  AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
    [$2], [$3])
])

dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
dnl the current linker to avoid undefined references in a shared object.
AC_DEFUN([CC_NOUNDEFINED], [
  dnl We check $host for which systems to enable this for.
  AC_REQUIRE([AC_CANONICAL_HOST])

  case $host in
     dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads
     dnl are requested, as different implementations are present; to avoid problems
     dnl use -Wl,-z,defs only for those platform not behaving this way.
     *-freebsd* | *-openbsd*) ;;
     *)
        dnl First of all check for the --no-undefined variant of GNU ld. This allows
        dnl for a much more readable commandline, so that people can understand what
        dnl it does without going to look for what the heck -z defs does.
        for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
           CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
           break
        done
     ;;
  esac

  AC_SUBST([LDFLAGS_NOUNDEFINED])
])

dnl Check for a -Werror flag or equivalent. -Werror is the GCC
dnl and ICC flag that tells the compiler to treat all the warnings
dnl as fatal. We usually need this option to make sure that some
dnl constructs (like attributes) are not simply ignored.
dnl
dnl Other compilers don't support -Werror per se, but they support
dnl an equivalent flag:
dnl  - Sun Studio compiler supports -errwarn=%all
AC_DEFUN([CC_CHECK_WERROR], [
  AC_CACHE_CHECK(
    [for $CC way to treat warnings as errors],
    [cc_cv_werror],
    [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
      [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
    ])
])

AC_DEFUN([CC_CHECK_ATTRIBUTE], [
  AC_REQUIRE([CC_CHECK_WERROR])
  AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
    AS_TR_SH([cc_cv_attribute_$1]),
    [ac_save_CFLAGS="$CFLAGS"
     CFLAGS="$CFLAGS $cc_cv_werror"
     AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
       [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
       [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
     CFLAGS="$ac_save_CFLAGS"
    ])

  AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
    [AC_DEFINE(
       AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
         [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
         )
     $4],
    [$5])
])

AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
  CC_CHECK_ATTRIBUTE(
    [constructor],,
    [void __attribute__((constructor)) ctor() { int a; }],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
  CC_CHECK_ATTRIBUTE(
    [format], [format(printf, n, n)],
    [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
  CC_CHECK_ATTRIBUTE(
    [format_arg], [format_arg(printf)],
    [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
  CC_CHECK_ATTRIBUTE(
    [visibility_$1], [visibility("$1")],
    [void __attribute__((visibility("$1"))) $1_function() { }],
    [$2], [$3])
])

AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
  CC_CHECK_ATTRIBUTE(
    [nonnull], [nonnull()],
    [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
  CC_CHECK_ATTRIBUTE(
    [unused], ,
    [void some_function(void *foo, __attribute__((unused)) void *bar);],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
  CC_CHECK_ATTRIBUTE(
    [sentinel], ,
    [void some_function(void *foo, ...) __attribute__((sentinel));],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
  CC_CHECK_ATTRIBUTE(
    [deprecated], ,
    [void some_function(void *foo, ...) __attribute__((deprecated));],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
  CC_CHECK_ATTRIBUTE(
    [alias], [weak, alias],
    [void other_function(void *foo) { }
     void some_function(void *foo) __attribute__((weak, alias("other_function")));],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
  CC_CHECK_ATTRIBUTE(
    [malloc], ,
    [void * __attribute__((malloc)) my_alloc(int n);],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_PACKED], [
  CC_CHECK_ATTRIBUTE(
    [packed], ,
    [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
    [$1], [$2])
])

AC_DEFUN([CC_ATTRIBUTE_CONST], [
  CC_CHECK_ATTRIBUTE(
    [const], ,
    [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
    [$1], [$2])
])

AC_DEFUN([CC_FLAG_VISIBILITY], [
  AC_REQUIRE([CC_CHECK_WERROR])
  AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
    [cc_cv_flag_visibility],
    [cc_flag_visibility_save_CFLAGS="$CFLAGS"
     CFLAGS="$CFLAGS $cc_cv_werror"
     CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
     cc_cv_flag_visibility='yes',
     cc_cv_flag_visibility='no')
     CFLAGS="$cc_flag_visibility_save_CFLAGS"])

  AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
    [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
       [Define this if the compiler supports the -fvisibility flag])
     $1],
    [$2])
])

AC_DEFUN([CC_FUNC_EXPECT], [
  AC_REQUIRE([CC_CHECK_WERROR])
  AC_CACHE_CHECK([if compiler has __builtin_expect function],
    [cc_cv_func_expect],
    [ac_save_CFLAGS="$CFLAGS"
     CFLAGS="$CFLAGS $cc_cv_werror"
     AC_COMPILE_IFELSE([AC_LANG_SOURCE(
       [int some_function() {
        int a = 3;
        return (int)__builtin_expect(a, 3);
     }])],
       [cc_cv_func_expect=yes],
       [cc_cv_func_expect=no])
     CFLAGS="$ac_save_CFLAGS"
    ])

  AS_IF([test "x$cc_cv_func_expect" = "xyes"],
    [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
     [Define this if the compiler supports __builtin_expect() function])
     $1],
    [$2])
])

AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
  AC_REQUIRE([CC_CHECK_WERROR])
  AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
    [cc_cv_attribute_aligned],
    [ac_save_CFLAGS="$CFLAGS"
     CFLAGS="$CFLAGS $cc_cv_werror"
     for cc_attribute_align_try in 64 32 16 8 4 2; do
        AC_COMPILE_IFELSE([AC_LANG_SOURCE([
          int main() {
            static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
            return c;
          }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
     done
     CFLAGS="$ac_save_CFLAGS"
  ])

  if test "x$cc_cv_attribute_aligned" != "x"; then
     AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
       [Define the highest alignment supported])
  fi
])