[PATCH] [gdb/tui] Don't show incorrect source file in source window

[Tom de Vries <tdevries@suse.de>]

Consider the test-case sources main.c and foo.c:
...
$ cat main.c
extern int foo (void);

int
main (void)
{
  return foo ();
}
$ cat foo.c
extern int foo (void);

int
foo (void)
{
  return 0;
}
...
and main.c compiled with debug info, and foo.c without:
...
$ gcc -g main.c -c
$ gcc foo.c -c
$ gcc -g main.o foo.o
...

In TUI mode, if we run to foo:
...
$ gdb -q a.out -tui -ex "b foo" -ex run
...
it gets us "[ No Source Available ]":
...
┌─main.c─────────────────────────────────────────┐
│                                                │
│                                                │
│                                                │
│            [ No Source Available ]             │
│                                                │
│                                                │
└────────────────────────────────────────────────┘
(src) In: foo                  L??   PC: 0x400566
db.so.1".

Breakpoint 1, 0x0000000000400566 in foo ()
(gdb)
...

But after resizing (pressing ctrl-<minus> in the gnome-terminal), we get
instead the source for main.c:
...
┌─main.c───────────────────────────────────────────────────┐
│        3 int                                             │
│        4 main (void)                                     │
│        5 {                                               │
│        6   return foo ();                                │
│        7 }                                               │
│                                                          │
│                                                          │
└──────────────────────────────────────────────────────────┘
(src) In: foo                            L??   PC: 0x400566
db.so.1".

Breakpoint 1, 0x0000000000400566 in foo ()
(gdb)
...
which is inappropriate because we're stopped in function foo, which is not in
main.c.

Fix this in tui_source_window_base::rerender.

Tested on x86_64-linux.

Reported-By: Andrew Burgess <aburgess@redhat.com>

PR tui/32614
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32614
---
 gdb/testsuite/gdb.tui/resize-3-foo.c  | 24 ++++++++++
 gdb/testsuite/gdb.tui/resize-3-main.c | 24 ++++++++++
 gdb/testsuite/gdb.tui/resize-3.exp    | 63 +++++++++++++++++++++++++++
 gdb/tui/tui-winsource.c               |  6 +++
 4 files changed, 117 insertions(+)
 create mode 100644 gdb/testsuite/gdb.tui/resize-3-foo.c
 create mode 100644 gdb/testsuite/gdb.tui/resize-3-main.c
 create mode 100644 gdb/testsuite/gdb.tui/resize-3.exp

diff --git a/gdb/testsuite/gdb.tui/resize-3-foo.c b/gdb/testsuite/gdb.tui/resize-3-foo.c
new file mode 100644
index 00000000000..653b24ba92b
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/resize-3-foo.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2025 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/>.  */
+
+extern int foo (void);
+
+int
+foo (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.tui/resize-3-main.c b/gdb/testsuite/gdb.tui/resize-3-main.c
new file mode 100644
index 00000000000..95fdd3b6ba0
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/resize-3-main.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2025 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/>.  */
+
+extern int foo (void);
+
+int
+main (void)
+{
+  return foo ();
+}
diff --git a/gdb/testsuite/gdb.tui/resize-3.exp b/gdb/testsuite/gdb.tui/resize-3.exp
new file mode 100644
index 00000000000..ec022b4a177
--- /dev/null
+++ b/gdb/testsuite/gdb.tui/resize-3.exp
@@ -0,0 +1,63 @@
+# Copyright 2025 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 TUI resizing while showing "No Source Available".
+
+require allow_tui_tests
+
+standard_testfile -main.c -foo.c
+
+if { [build_executable_from_specs "failed to prepare" \
+	  $testfile {debug} \
+	  $srcfile {debug} \
+	  $srcfile2 {nodebug}] == -1 } {
+    return -1
+}
+
+tuiterm_env
+
+Term::clean_restart 24 80 $testfile
+
+# It would be simpler to run directly to foo and then enter TUI, but that
+# fails to trigger PR32614.  So instead, we first run to main, enter TUI and
+# then run to foo.
+if {![runto_main]} {
+    perror "test suppressed"
+    return
+}
+
+# Set a breakpoint on foo, easier to do before entering TUI.
+gdb_breakpoint foo
+
+if {![Term::enter_tui]} {
+    unsupported "TUI not supported"
+    return
+}
+
+# Continue to foo.
+Term::command continue
+
+with_test_prefix "before resize" {
+    Term::check_contents "Source window empty" \
+	"No Source Available"
+}
+
+Term::resize 40 90
+
+with_test_prefix "after resize" {
+    # Regression test for PR32614.
+    Term::check_contents "Source window empty" \
+	"No Source Available"
+}
diff --git a/gdb/tui/tui-winsource.c b/gdb/tui/tui-winsource.c
index a5d0c594545..bf4052755df 100644
--- a/gdb/tui/tui-winsource.c
+++ b/gdb/tui/tui-winsource.c
@@ -460,6 +460,12 @@ tui_source_window_base::rerender ()
       struct gdbarch *gdbarch = get_frame_arch (frame);
 
       struct symtab *s = find_pc_line_symtab (get_frame_pc (frame));
+      if (s == nullptr)
+	{
+	  erase_source_content ();
+	  return;
+	}
+
       if (this != tui_src_win ())
 	find_line_pc (s, cursal.line, &cursal.pc);
 

base-commit: d1b55b91df48f26a8541646bb88231ad5b9a0832
-- 
2.43.0