binutils-gdb/config/gcc-plugin.m4

# 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="$ac_cv_prog_OBJDUMP -T"
       elif test x$host = x$target; then
	 export_sym_check="$gcc_cv_objdump -T"
       else
	 export_sym_check="$ac_cv_prog_OBJDUMP -T"
       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 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 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"
     saved_CXXFLAGS="$CXXFLAGS"
     case "${host}" in
       *-*-darwin*)
	 CFLAGS=`echo $CFLAGS | sed s/-mdynamic-no-pic//g`
	 CFLAGS="$CFLAGS -fPIC"
	 CXXFLAGS=`echo $CXXFLAGS | sed s/-mdynamic-no-pic//g`
	 CXXFLAGS="$CXXFLAGS -fPIC"
	 LDFLAGS="$LDFLAGS -shared -undefined dynamic_lookup"
       ;;
       *)
	 CFLAGS="$CFLAGS -fPIC"
	 CXXFLAGS="$CXXFLAGS -fPIC"
	 LDFLAGS="$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"
     CXXFLAGS="$saved_CXXFLAGS"

     # 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
])

dnl
dnl
dnl GCC_PLUGIN_OPTION
dnl    (SHELL-CODE_HANDLER)
dnl
AC_DEFUN([GCC_PLUGIN_OPTION],[dnl
AC_CHECK_TOOL(AR, ar)
if test -z "${AR}"; then
  AC_MSG_ERROR([Required archive tool 'ar' not found on PATH.])
fi
AC_MSG_CHECKING([for -plugin option])
plugin_names="liblto_plugin.so liblto_plugin-0.dll cyglto_plugin-0.dll"
plugin_option=
for plugin in $plugin_names; do
  plugin_so=`${CC} ${CFLAGS} --print-prog-name $plugin`
  if test x$plugin_so = x$plugin; then
    plugin_so=`${CC} ${CFLAGS} --print-file-name $plugin`
  fi
  if test x$plugin_so != x$plugin; then
    plugin_option="--plugin $plugin_so"
    break
  fi
done
if test -z "$plugin_option"; then
  AC_MSG_RESULT([no])
else
  AC_MSG_RESULT($plugin_option)
  dnl Check if ${AR} $plugin_option rc works.
  touch conftest.c
  ${AR} $plugin_option rc conftest.a conftest.c
  if test "$?" != 0; then
    AC_MSG_WARN([Failed: $AR $plugin_option rc])
    plugin_option=
  fi
  rm -f conftest.*
fi
$1="$plugin_option"
])

dnl
dnl
dnl GCC_PLUGIN_OPTION_FOR_TARGET
dnl    (SHELL-CODE_HANDLER)
dnl
AC_DEFUN([GCC_PLUGIN_OPTION_FOR_TARGET],[dnl
COMPILER_FOR_TARGET="${CC_FOR_TARGET}"
dnl Check if the host compiler is used.
if test x"${COMPILER_FOR_TARGET}" = x"\$(CC)"; then
  COMPILER_FOR_TARGET="$CC"
fi
saved_CC="$CC"
CC="$COMPILER_FOR_TARGET"
AC_CACHE_CHECK([for gcc for target], gcc_target_cv_working, [
  AC_TRY_COMPILE(
  [],
  [],
  gcc_target_cv_working=yes,
  gcc_target_cv_working=no)])
CC="$saved_CC"
AC_MSG_CHECKING([for target -plugin option])
plugin_option=
if test $gcc_target_cv_working = yes; then
  plugin_names="liblto_plugin.so liblto_plugin-0.dll cyglto_plugin-0.dll"
  for plugin in $plugin_names; do
    plugin_so=`${COMPILER_FOR_TARGET} ${CFLAGS_FOR_TARGET} --print-prog-name $plugin`
    if test x$plugin_so = x$plugin; then
      plugin_so=`${COMPILER_FOR_TARGET} ${CFLAGS_FOR_TARGET} --print-file-name $plugin`
    fi
    if test x$plugin_so != x$plugin; then
      plugin_option="--plugin $plugin_so"
      break
    fi
  done
fi
if test -z "$plugin_option"; then
  AC_MSG_RESULT([no])
else
  AC_MSG_RESULT($plugin_option)
fi
$1="$plugin_option"
])