Index: gdb.ada/lang_switch.exp
===================================================================
--- gdb.ada/lang_switch.exp	(revision 0)
+++ gdb.ada/lang_switch.exp	(revision 121)
@@ -0,0 +1,48 @@
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+load_lib "ada.exp"
+
+set testdir "lang_switch"
+set testfile "${testdir}/lang_switch"
+set cfile "${testdir}/foo"
+set adasrcfile ${srcdir}/${subdir}/${testfile}.adb
+set csrcfile ${srcdir}/${subdir}/${cfile}.c
+set cobject  ${objdir}/${subdir}/${cfile}.o
+set binfile ${objdir}/${subdir}/${testfile}
+
+file mkdir ${objdir}/${subdir}/${testdir}
+gdb_compile "${csrcfile}" "${cobject}" object [list debug]
+if {[gdb_compile_ada "${adasrcfile}" "${binfile}" executable [list debug]] != "" } {
+  return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set bp_location [gdb_get_line_number "STOP" ${testdir}/foo.c]
+runto "foo.c:$bp_location"
+
+# Make sure that the language is switched to Ada for the second frame
+# by checking the string parameter.
+gdb_test "bt" \
+         ".*#1.*lang_switch\.ada_procedure\\s*\\(msg=$hex\\).*" \
+         "backtrace"
Index: gdb.ada/lang_switch/foo.c
===================================================================
--- gdb.ada/lang_switch/foo.c	(revision 0)
+++ gdb.ada/lang_switch/foo.c	(revision 121)
@@ -0,0 +1,22 @@
+/* Copyright 2008 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+c_procedure (char* msg)
+{
+  return 0; /* STOP */
+}
Index: gdb.ada/lang_switch/lang_switch.adb
===================================================================
--- gdb.ada/lang_switch/lang_switch.adb	(revision 0)
+++ gdb.ada/lang_switch/lang_switch.adb	(revision 121)
@@ -0,0 +1,34 @@
+--  Copyright 2008 Free Software Foundation, Inc.
+--
+--  This program is free software; you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation; either version 3 of the License, or
+--  (at your option) any later version.
+--
+--  This program is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+with System;
+
+procedure Lang_Switch is
+   pragma Linker_Options ("foo.o");
+
+   function C_Procedure (Msg : String) return Integer;
+   pragma Import(C, C_Procedure, "c_procedure");
+
+   procedure Ada_Procedure (Msg : String) is
+      C_Msg : String (1 .. 1024);
+      Tmp_Int : Integer;
+   begin
+      C_Msg  (1 .. Msg'length   + 1) := Msg & Ascii.Nul;
+      Tmp_Int := C_Procedure (Msg => C_Msg);
+   end Ada_Procedure;
+
+begin
+   Ada_Procedure ("msg");
+end Lang_Switch;