[PATCH 3/6] gdb: fix display of thread condition for multi-location breakpoints

[Andrew Burgess <aburgess@redhat.com>]

If a breakpoint with multiple locations has a thread condition, then
the 'info breakpoints' output is a little messed up, here's an example
of the current output:

  (gdb) break foo thread 1
  Breakpoint 2 at 0x401114: foo. (3 locations)
  (gdb) break bar thread 1
  Breakpoint 3 at 0x40110a: file /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c, line 32.
  (gdb) info breakpoints
  Num     Type           Disp Enb Address            What
  2       breakpoint     keep y   <MULTIPLE>          thread 1
          stop only in thread 1
  2.1                         y   0x0000000000401114 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25
  2.2                         y   0x0000000000401146 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25
  2.3                         y   0x0000000000401168 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25
  3       breakpoint     keep y   0x000000000040110a in bar at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:32 thread 1
          stop only in thread 1

Notice that, at the end of the location for breakpoint 3, the 'thread
1' condition is printed.

In contrast, for breakpoint 2, the 'thread 1' appears randomly, in the
"What" column, though slightly offset.

I believe this is a bug in GDB, in the function
print_one_breakpoint_location, due to checking the local variable
part_of_multiple, instead of header_of_multiple.

If I fix this oversight, then the output is now:

  (gdb) break foo thread 1
  Breakpoint 2 at 0x401114: foo. (3 locations)
  (gdb) break bar thread 1
  Breakpoint 3 at 0x40110a: file /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c, line 32.
  (gdb) info breakpoints
  Num     Type           Disp Enb Address            What
  2       breakpoint     keep y   <MULTIPLE>
          stop only in thread 1
  2.1                         y   0x0000000000401114 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25 thread 1
  2.2                         y   0x0000000000401146 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25 thread 1
  2.3                         y   0x0000000000401168 in foo at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:25 thread 1
  3       breakpoint     keep y   0x000000000040110a in bar at /tmp/src/gdb/testsuite/gdb.base/thread-bp-multi-loc.c:32 thread 1
          stop only in thread 1

The 'thread 1' condition is now displayed at the end of each location,
which makes the output the same for single location breakpoints and
multi-location breakpoints.
---
 gdb/breakpoint.c                              |  2 +-
 gdb/testsuite/gdb.base/thread-bp-multi-loc.c  | 44 ++++++++++
 .../gdb.base/thread-bp-multi-loc.exp          | 88 +++++++++++++++++++
 3 files changed, 133 insertions(+), 1 deletion(-)
 create mode 100644 gdb/testsuite/gdb.base/thread-bp-multi-loc.c
 create mode 100644 gdb/testsuite/gdb.base/thread-bp-multi-loc.exp

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index f0276a963c0..2ec8ca364b6 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -6467,7 +6467,7 @@ print_one_breakpoint_location (struct breakpoint *b,
       output_thread_groups (uiout, "thread-groups", inf_nums, mi_only);
     }
 
-  if (!part_of_multiple)
+  if (!header_of_multiple)
     {
       if (b->thread != -1)
 	{
diff --git a/gdb/testsuite/gdb.base/thread-bp-multi-loc.c b/gdb/testsuite/gdb.base/thread-bp-multi-loc.c
new file mode 100644
index 00000000000..cab009c39ec
--- /dev/null
+++ b/gdb/testsuite/gdb.base/thread-bp-multi-loc.c
@@ -0,0 +1,44 @@
+/* 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/>.  */
+
+volatile int global_var = 0;
+
+__attribute__((__always_inline__)) static inline void
+foo (void)
+{
+  int i;
+
+  for (i = 0; i < 10; ++i)
+    global_var = i;
+}
+
+static void
+bar (void)
+{
+  global_var = 0;
+  foo ();
+}
+
+int
+main (void)
+{
+  global_var = 0;
+  foo ();
+  bar ();
+  foo ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.base/thread-bp-multi-loc.exp b/gdb/testsuite/gdb.base/thread-bp-multi-loc.exp
new file mode 100644
index 00000000000..9abff5866d9
--- /dev/null
+++ b/gdb/testsuite/gdb.base/thread-bp-multi-loc.exp
@@ -0,0 +1,88 @@
+# 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/>.
+
+# Create a multi-location breakpoint with a thread condition, then check the
+# output of 'info breakpoints' to ensure that the thread condition is
+# displayed correctly.
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
+    return
+}
+
+if ![runto_main] then {
+    return
+}
+
+gdb_test_no_output "with confirm off -- delete breakpoints"
+
+set bp_number ""
+gdb_test_multiple "break foo thread 1" "" {
+    -re "^break foo thread 1\r\n" {
+	exp_continue
+    }
+    -re "^Breakpoint ($decimal) at $hex: foo\[^\r\n\]+3 locations\[^\r\n\]+\r\n" {
+	set bp_number $expect_out(1,string)
+	exp_continue
+    }
+    -re "^$gdb_prompt $" {
+	gdb_assert { ![string eq $bp_number ""] }
+    }
+}
+
+if { $bp_number == "" } {
+    unresolved "breakpoint not placed correctly"
+    return
+}
+
+set saw_header false
+set saw_cond false
+set loc_count 0
+gdb_test_multiple "info breakpoints" "" {
+    -re "^info breakpoints\r\n" {
+	exp_continue
+    }
+
+    -re "^Num\\s+\[^\r\n\]+\r\n" {
+	exp_continue
+    }
+
+    -re "^$bp_number\\s+breakpoint\\s+keep\\s+y\\s+<MULTIPLE>\\s*\r\n" {
+	set saw_header true
+	exp_continue
+    }
+
+    -re "^\\s+stop only in thread 1\r\n" {
+	set saw_cond true
+	exp_continue
+    }
+
+    -re "^$bp_number\\.\[123\]\\s+\[^\r\n\]+ thread 1\r\n" {
+	incr loc_count
+	exp_continue
+    }
+
+    -re "^$gdb_prompt $" {
+	with_test_prefix $gdb_test_name {
+	    gdb_assert { $saw_header } \
+		"saw header line"
+	    gdb_assert { $saw_cond } \
+		"saw b/p condition line"
+	    gdb_assert { $loc_count == 3 } \
+		"saw all three locations"
+	}
+    }
+}
-- 
2.25.4