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# gcc-plugin.m4 -*- Autoconf -*-
# Check whether GCC is able to be built with plugin support.
dnl Copyright (C) 2014 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License. As a special exception to the GNU General
dnl Public License, this file may be distributed as part of a program
dnl that contains a configuration script generated by Autoconf, under
dnl the same distribution terms as the rest of that program.
# Check for plugin support.
# Respects --enable-plugin.
# Sets the shell variables enable_plugin and pluginlibs.
AC_DEFUN([GCC_ENABLE_PLUGINS],
[# Check for plugin support
AC_ARG_ENABLE(plugin,
[AS_HELP_STRING([--enable-plugin], [enable plugin support])],
enable_plugin=$enableval,
enable_plugin=yes; default_plugin=yes)
pluginlibs=
plugin_check=yes
case "${host}" in
*-*-mingw*)
# Since plugin support under MinGW is not as straightforward as on
# other platforms (e.g., we have to link import library, etc), we
# only enable it if explicitly requested.
if test x"$default_plugin" = x"yes"; then
enable_plugin=no
elif test x"$enable_plugin" = x"yes"; then
# Use make's target variable to derive import library name.
pluginlibs='-Wl,--export-all-symbols -Wl,--out-implib=[$]@.a'
plugin_check=no
fi
;;
*-*-darwin*)
if test x$build = x$host; then
export_sym_check="nm${exeext} -g"
elif test x$host = x$target; then
export_sym_check="$gcc_cv_nm -g"
else
export_sym_check=
fi
;;
*)
if test x$build = x$host; then
export_sym_check="objdump${exeext} -T"
elif test x$host = x$target; then
export_sym_check="$gcc_cv_objdump -T"
else
export_sym_check=
fi
;;
esac
if test x"$enable_plugin" = x"yes" -a x"$plugin_check" = x"yes"; then
AC_MSG_CHECKING([for exported symbols])
if test "x$export_sym_check" != x; then
echo "int main() {return 0;} int foobar() {return 0;}" > conftest.c
${CC} ${CFLAGS} ${LDFLAGS} conftest.c -o conftest$ac_exeext > /dev/null 2>&1
if $export_sym_check conftest$ac_exeext | grep -q foobar > /dev/null; then
: # No need to use a flag
AC_MSG_RESULT([yes])
else
AC_MSG_RESULT([yes])
AC_MSG_CHECKING([for -rdynamic])
${CC} ${CFLAGS} ${LDFLAGS} -rdynamic conftest.c -o conftest$ac_exeext > /dev/null 2>&1
if $export_sym_check conftest$ac_exeext | grep -q foobar > /dev/null; then
plugin_rdynamic=yes
pluginlibs="-rdynamic"
else
plugin_rdynamic=no
enable_plugin=no
fi
AC_MSG_RESULT([$plugin_rdynamic])
fi
else
AC_MSG_RESULT([unable to check])
fi
# Check -ldl
saved_LIBS="$LIBS"
AC_SEARCH_LIBS([dlopen], [dl])
if test x"$ac_cv_search_dlopen" = x"-ldl"; then
pluginlibs="$pluginlibs -ldl"
fi
LIBS="$saved_LIBS"
# Check that we can build shared objects with -fPIC -shared
saved_LDFLAGS="$LDFLAGS"
saved_CFLAGS="$CFLAGS"
case "${host}" in
*-*-darwin*)
CFLAGS=`echo $CFLAGS | sed s/-mdynamic-no-pic//g`
CFLAGS="$CFLAGS -fPIC"
LDFLAGS="$LDFLAGS -shared -undefined dynamic_lookup"
;;
*)
CFLAGS="$CFLAGS -fPIC"
LDFLAGS="$LDFLAGS -fPIC -shared"
;;
esac
AC_MSG_CHECKING([for -fPIC -shared])
AC_TRY_LINK(
[extern int X;],[return X == 0;],
[AC_MSG_RESULT([yes]); have_pic_shared=yes],
[AC_MSG_RESULT([no]); have_pic_shared=no])
if test x"$have_pic_shared" != x"yes" -o x"$ac_cv_search_dlopen" = x"no"; then
pluginlibs=
enable_plugin=no
fi
LDFLAGS="$saved_LDFLAGS"
CFLAGS="$saved_CFLAGS"
# If plugin support had been requested but not available, fail.
if test x"$enable_plugin" = x"no" ; then
if test x"$default_plugin" != x"yes"; then
AC_MSG_ERROR([
Building GCC with plugin support requires a host that supports
-fPIC, -shared, -ldl and -rdynamic.])
fi
fi
fi
])
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