src/installer/m4/attributes.m4

   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>
   5 dnl
   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)
   9 dnl any later version.
  10 dnl
  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.
  15 dnl
  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
  19 dnl 02110-1301, USA.
  20 dnl
  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.
  29 dnl
  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
  34 dnl well.
  35
  36 dnl Check if FLAG in ENV-VAR is supported by compiler and append it
  37 dnl to WHERE-TO-APPEND variable
  38 dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
  39
  40 AC_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
  54 dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
  55 AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
  56   for flag in $3; do
  57     CC_CHECK_FLAG_APPEND($1, $2, $flag)
  58   done
  59 ])
  60
  61 dnl Check if the flag is supported by linker (cacheable)
  62 dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
  63
  64 AC_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
  79 dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
  80 dnl the current linker to avoid undefined references in a shared object.
  81 AC_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
 104 dnl Check for a -Werror flag or equivalent. -Werror is the GCC
 105 dnl and ICC flag that tells the compiler to treat all the warnings
 106 dnl as fatal. We usually need this option to make sure that some
 107 dnl constructs (like attributes) are not simply ignored.
 108 dnl
 109 dnl Other compilers don't support -Werror per se, but they support
 110 dnl an equivalent flag:
 111 dnl  - Sun Studio compiler supports -errwarn=%all
 112 AC_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
 121 AC_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
 142 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
 143   CC_CHECK_ATTRIBUTE(
 144     [constructor],,
 145     [void __attribute__((constructor)) ctor() { int a; }],
 146     [$1], [$2])
 147 ])
 148
 149 AC_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
 156 AC_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
 163 AC_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
 170 AC_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
 177 AC_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
 184 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
 185   CC_CHECK_ATTRIBUTE(
 186     [sentinel], ,
 187     [void some_function(void *foo, ...) __attribute__((sentinel));],
 188     [$1], [$2])
 189 ])
 190
 191 AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
 192   CC_CHECK_ATTRIBUTE(
 193     [deprecated], ,
 194     [void some_function(void *foo, ...) __attribute__((deprecated));],
 195     [$1], [$2])
 196 ])
 197
 198 AC_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
 206 AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
 207   CC_CHECK_ATTRIBUTE(
 208     [malloc], ,
 209     [void * __attribute__((malloc)) my_alloc(int n);],
 210     [$1], [$2])
 211 ])
 212
 213 AC_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
 220 AC_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
 227 AC_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     [$2])
 243 ])
 244
 245 AC_DEFUN([CC_FUNC_EXPECT], [
 246   AC_REQUIRE([CC_CHECK_WERROR])
 247   AC_CACHE_CHECK([if compiler has __builtin_expect function],
 248     [cc_cv_func_expect],
 249     [ac_save_CFLAGS="$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     [$2])
 266 ])
 267
 268 AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
 269   AC_REQUIRE([CC_CHECK_WERROR])
 270   AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
 271     [cc_cv_attribute_aligned],
 272     [ac_save_CFLAGS="$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 ])