gdb: don't print global thread-id to CLI in describe_other_breakpoints

I noticed that describe_other_breakpoints was printing the global
thread-id to the CLI.  For CLI output we should be printing the
inferior local thread-id (e.g. "2.1").  This can be seen in the
following GDB session:

  (gdb) info threads
    Id   Target Id                                Frame
    1.1  Thread 4065742.4065742 "bp-thread-speci" main () at /tmp/bp-thread-specific.c:27
  * 2.1  Thread 4065743.4065743 "bp-thread-speci" main () at /tmp/bp-thread-specific.c:27
  (gdb) break foo thread 2.1
  Breakpoint 3 at 0x40110a: foo. (2 locations)
  (gdb) break foo thread 1.1
  Note: breakpoint 3 (thread 2) also set at pc 0x40110a.
  Note: breakpoint 3 (thread 2) also set at pc 0x40110a.
  Breakpoint 4 at 0x40110a: foo. (2 locations)

Notice that GDB says:

  Note: breakpoint 3 (thread 2) also set at pc 0x40110a.

The 'thread 2' in here is using the global thread-id, we should
instead say 'thread 2.1' which corresponds to how the user specified
the breakpoint.

This commit fixes this issue and adds a test.

Approved-By: Pedro Alves <pedro@palves.net>

2 files changed, 89 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.multi/bp-thread-specific.c b/gdb/testsuite/gdb.multi/bp-thread-specific.c
new file mode 100644
index 0000000..51b6492
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/bp-thread-specific.c
@@ -0,0 +1,28 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 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/>.  */
+
+int
+foo ()
+{
+  return 0;
+}
+
+int
+main ()
+{
+  return foo ();
+}
diff --git a/gdb/testsuite/gdb.multi/bp-thread-specific.exp b/gdb/testsuite/gdb.multi/bp-thread-specific.exp
new file mode 100644
index 0000000..777fcf8
--- /dev/null
+++ b/gdb/testsuite/gdb.multi/bp-thread-specific.exp
@@ -0,0 +1,61 @@
+# Copyright 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/>.
+
+# Check that GDB uses the correct thread-id when describing multiple
+# thread specific breakpoints at the same location.
+
+# The plain remote target can't do multiple inferiors.
+require !use_gdb_stub
+
+standard_testfile
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile]} {
+    return -1
+}
+
+if {![runto_main]} {
+    return -1
+}
+
+gdb_test "add-inferior -exec ${binfile}" "Added inferior 2.*" "add inferior 2"
+gdb_test "inferior 2"
+
+if {![runto_main]} {
+    return -1
+}
+
+gdb_test "info threads" \
+    [multi_line \
+	 "  Id\\s+Target Id\\s+Frame\\s*" \
+	 "  1\\.1\\s+\[^\r\n\]+" \
+	 "\\* 2\\.1\\s+\[^\r\n\]+"] \
+    "check we have the expected threads"
+
+# Set the first breakpoint.  Currently this is going to insert at two
+# locations ('foo' in both inferiors) even though only one of those
+# locations will ever trigger ('foo' in inferior 2).
+gdb_test "break foo thread 2.1" \
+    "Breakpoint $decimal at $hex: foo\\. \\(2 locations\\)"
+
+set bpnum [get_integer_valueof "\$bpnum" "INVALID"]
+
+# Now set another breakpoint that will be at the same location as the
+# earlier breakpoint.  Check that the thread-id used when describing
+# the earlier breakpoints is correct.
+gdb_test "break foo thread 1.1" \
+    [multi_line \
+	 "Note: breakpoint $bpnum \\(thread 2.1\\) also set at pc $hex\\." \
+	 "Note: breakpoint $bpnum \\(thread 2.1\\) also set at pc $hex\\." \
+	 "Breakpoint $decimal at $hex: foo\\. \\(2 locations\\)"]