Fix parameter-less template regression in new DWARF reader

PR c++/29896 points out a regression in the new DWARF reader.  It does
not properly handle a case like "break fn", where "fn" is a template
function.

This happens because the new index uses strncasecmp to compare.
However, to make this work correctly, we need a custom function that
ignores template parameters.

This patch adds a custom comparison function and fixes the bug.  A new
test case is included.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29896

2 files changed, 87 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.cp/paramless.cc b/gdb/testsuite/gdb.cp/paramless.cc
new file mode 100644
index 0000000..8292439
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/paramless.cc
@@ -0,0 +1,46 @@
+/* Test case for template breakpoint test.
+
+   Copyright 2022-2023 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/>.  */
+
+template<typename T>
+struct outer
+{
+  template<typename Q = int>
+  int fn (int x)
+  {
+    return x + 23;
+  }
+};
+
+template<typename T = int>
+int toplev (int y)
+{
+  return y;
+}
+
+outer<int> outer1;
+outer<char> outer2;
+
+int main ()
+{
+  int x1 = outer1.fn (0);
+  int x2 = outer2.fn<short> (-46);
+  int x3 = toplev<char> (0);
+  int x4 = toplev (0);
+  return x1 + x2;
+}
diff --git a/gdb/testsuite/gdb.cp/paramless.exp b/gdb/testsuite/gdb.cp/paramless.exp
new file mode 100644
index 0000000..79529de
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/paramless.exp
@@ -0,0 +1,41 @@
+# Copyright 2022-2023 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/>.
+
+# This file is part of the gdb testsuite.
+
+# Test template breakpoints without parameters.
+
+if { [skip_cplus_tests] } { continue }
+
+standard_testfile .cc
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+gdb_breakpoint "outer<int>::fn" message
+delete_breakpoints
+
+gdb_breakpoint "outer<char>::fn<short>" message
+delete_breakpoints
+
+gdb_test "break outer::fn" "Breakpoint $decimal at .*2 locations."
+delete_breakpoints
+
+gdb_test "break toplev" "Breakpoint $decimal at .*2 locations."
+delete_breakpoints
+
+gdb_breakpoint "toplev<char>" message
+delete_breakpoints