[pushed] Add C++ "save gdb-index" test

[Tom Tromey <tom@tromey.com>]

I found a bug in the new DWARF reader series, related to the handling
of enumerator names.  This bug caused a crash, so this patch adds a
regression test for this particular case.  I'm checking this in.
---
 gdb/testsuite/gdb.dwarf2/gdb-index-cxx.exp | 35 ++++++++++++++++++++++
 gdb/testsuite/gdb.dwarf2/index.cc          | 29 ++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 gdb/testsuite/gdb.dwarf2/gdb-index-cxx.exp
 create mode 100644 gdb/testsuite/gdb.dwarf2/index.cc

diff --git a/gdb/testsuite/gdb.dwarf2/gdb-index-cxx.exp b/gdb/testsuite/gdb.dwarf2/gdb-index-cxx.exp
new file mode 100644
index 00000000000..26ecdec962a
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/gdb-index-cxx.exp
@@ -0,0 +1,35 @@
+# Copyright 2022 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/>.
+
+load_lib dwarf.exp
+
+standard_testfile index.cc
+
+if {[prepare_for_testing "failed to prepare" "${testfile}" \
+	 [list ${srcfile}]]} {
+    return -1
+}
+
+# The bug was that gdb would crash when saving.
+set output_dir [standard_output_file ""]
+set cmd "save gdb-index"
+gdb_test_multiple "$cmd $output_dir" $cmd {
+    -re -wrap "Cannot use an index to create the index.*" {
+	unsupported $gdb_test_name
+    }
+    -re "^$cmd \[^\r\n\]*\r\n$gdb_prompt $" {
+	pass $gdb_test_name
+    }
+}
diff --git a/gdb/testsuite/gdb.dwarf2/index.cc b/gdb/testsuite/gdb.dwarf2/index.cc
new file mode 100644
index 00000000000..763e2f231b9
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/index.cc
@@ -0,0 +1,29 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2022 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/>.  */
+
+/* Test C++ index saving.  */
+
+enum E { ONE, TWO };
+E e_value = ONE;
+
+enum class EC { THREE, FOUR };
+EC ec_value = EC::THREE;
+
+int main ()
+{
+  return 0;
+}
-- 
2.34.1