1# gcc-plugin.m4 -*- Autoconf -*-
2# Check whether GCC is able to be built with plugin support.
3
4dnl Copyright (C) 2014 Free Software Foundation, Inc.
5dnl This file is free software, distributed under the terms of the GNU
6dnl General Public License.  As a special exception to the GNU General
7dnl Public License, this file may be distributed as part of a program
8dnl that contains a configuration script generated by Autoconf, under
9dnl the same distribution terms as the rest of that program.
10
11# Check for plugin support.
12# Respects --enable-plugin.
13# Sets the shell variables enable_plugin and pluginlibs.
14AC_DEFUN([GCC_ENABLE_PLUGINS],
15  [# Check for plugin support
16   AC_ARG_ENABLE(plugin,
17   [AS_HELP_STRING([--enable-plugin], [enable plugin support])],
18   enable_plugin=$enableval,
19   enable_plugin=yes; default_plugin=yes)
20
21   pluginlibs=
22   plugin_check=yes
23
24   case "${host}" in
25     *-*-mingw*)
26       # Since plugin support under MinGW is not as straightforward as on
27       # other platforms (e.g., we have to link import library, etc), we
28       # only enable it if explicitly requested.
29       if test x"$default_plugin" = x"yes"; then
30         enable_plugin=no
31       elif test x"$enable_plugin" = x"yes"; then
32         # Use make's target variable to derive import library name.
33         pluginlibs='-Wl,--export-all-symbols -Wl,--out-implib=[$]@.a'
34	 plugin_check=no
35       fi
36     ;;
37     *-*-darwin*)
38       if test x$build = x$host; then
39	 export_sym_check="nm${exeext} -g"
40       elif test x$host = x$target; then
41	 export_sym_check="$gcc_cv_nm -g"
42       else
43	 export_sym_check=
44       fi
45     ;;
46     *)
47       if test x$build = x$host; then
48	 export_sym_check="objdump${exeext} -T"
49       elif test x$host = x$target; then
50	 export_sym_check="$gcc_cv_objdump -T"
51       else
52	 export_sym_check=
53       fi
54     ;;
55   esac
56
57   if test x"$enable_plugin" = x"yes" -a x"$plugin_check" = x"yes"; then
58
59     AC_MSG_CHECKING([for exported symbols])
60     if test "x$export_sym_check" != x; then
61       echo "int main() {return 0;} int foobar() {return 0;}" > conftest.c
62       ${CC} ${CFLAGS} ${LDFLAGS} conftest.c -o conftest$ac_exeext > /dev/null 2>&1
63       if $export_sym_check conftest$ac_exeext | grep foobar > /dev/null; then
64	 : # No need to use a flag
65	 AC_MSG_RESULT([yes])
66       else
67	 AC_MSG_RESULT([yes])
68	 AC_MSG_CHECKING([for -rdynamic])
69	 ${CC} ${CFLAGS} ${LDFLAGS} -rdynamic conftest.c -o conftest$ac_exeext > /dev/null 2>&1
70	 if $export_sym_check conftest$ac_exeext | grep foobar > /dev/null; then
71	   plugin_rdynamic=yes
72	   pluginlibs="-rdynamic"
73	 else
74	   plugin_rdynamic=no
75	   enable_plugin=no
76	 fi
77	 AC_MSG_RESULT([$plugin_rdynamic])
78       fi
79     else
80       AC_MSG_RESULT([unable to check])
81     fi
82
83     # Check -ldl
84     saved_LIBS="$LIBS"
85     AC_SEARCH_LIBS([dlopen], [dl])
86     if test x"$ac_cv_search_dlopen" = x"-ldl"; then
87       pluginlibs="$pluginlibs -ldl"
88     fi
89     LIBS="$saved_LIBS"
90
91     # Check that we can build shared objects with -fPIC -shared
92     saved_LDFLAGS="$LDFLAGS"
93     saved_CFLAGS="$CFLAGS"
94     case "${host}" in
95       *-*-darwin*)
96	 CFLAGS=`echo $CFLAGS | sed s/-mdynamic-no-pic//g`
97	 CFLAGS="$CFLAGS -fPIC"
98	 LDFLAGS="$LDFLAGS -shared -undefined dynamic_lookup"
99       ;;
100       *)
101	 CFLAGS="$CFLAGS -fPIC"
102	 LDFLAGS="$LDFLAGS -fPIC -shared"
103       ;;
104     esac
105     AC_MSG_CHECKING([for -fPIC -shared])
106     AC_TRY_LINK(
107       [extern int X;],[return X == 0;],
108       [AC_MSG_RESULT([yes]); have_pic_shared=yes],
109       [AC_MSG_RESULT([no]); have_pic_shared=no])
110     if test x"$have_pic_shared" != x"yes" -o x"$ac_cv_search_dlopen" = x"no"; then
111       pluginlibs=
112       enable_plugin=no
113     fi
114     LDFLAGS="$saved_LDFLAGS"
115     CFLAGS="$saved_CFLAGS"
116
117     # If plugin support had been requested but not available, fail.
118     if test x"$enable_plugin" = x"no" ; then
119       if test x"$default_plugin" != x"yes"; then
120	 AC_MSG_ERROR([
121   Building GCC with plugin support requires a host that supports
122   -fPIC, -shared, -ldl and -rdynamic.])
123       fi
124     fi
125   fi
126])
127