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

dnl we don't test for that, it gives us false positives when gcc doesn't

dnl actually complain about it. If someone wants to compile this on sun, let

dnl them fix it.

AC_DEFUN([CC_CHECK_WERROR], [

  AC_CACHE_CHECK(

    [for $CC way to treat warnings as errors],

    [cc_cv_werror],

    [CC_CHECK_FLAG_APPEND([cc_cv_werror], [CFLAGS], [-Werror])])

])

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_CACHE_CHECK([if $CC supports -fvisibility=hidden],

    [cc_cv_flag_visibility],

    [CC_CHECK_FLAG_APPEND([cc_cv_flag_visibility], [CFLAGS], [-fvisibility=hidden])])

  AS_IF([test "x$cc_cv_flag_visibility" != "x"],

    [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

])