gdb/python: Fix segfault when iterating over empty linetable

symtab-> linetable () is set to null in
buildsym_compunit::end_compunit_symtab_with_blockvector () if the symtab
has no linetable. Attempting to iterate over this linetable using the
Python API caused GDB to segfault.

Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.python/py-linetable-empty.c b/gdb/testsuite/gdb.python/py-linetable-empty.c
new file mode 100644
index 0000000..85e5588
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-linetable-empty.c
@@ -0,0 +1,23 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2024 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/>.  */
+
+int
+main()
+{
+  asm ("main_label: .globl main_label");
+  return 0;
+}