[PATCH 3/3] gdb: don't use the global thread-id in the saved breakpoints file

[Andrew Burgess <aburgess@redhat.com>]

I noticed that breakpoint::print_recreate_thread was printing the
global thread-id.  This function is used to implement the 'save
breakpoints' command, and should be writing out suitable CLI commands
for recreating the current breakpoints.  The CLI does not use global
thread-ids, but instead uses the inferior specific thread-ids,
e.g. "2.1".

This commit updates breakpoint::print_recreate_thread to use the
print_thread_id function, and adds a test for this change.
---
 gdb/breakpoint.c                              |  5 +-
 .../gdb.multi/bp-thread-specific.exp          | 46 +++++++++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 6b576859592..6e3c76305e7 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -14120,7 +14120,10 @@ void
 breakpoint::print_recreate_thread (struct ui_file *fp) const
 {
   if (thread != -1)
-    gdb_printf (fp, " thread %d", thread);
+    {
+      struct thread_info *thr = find_thread_global_id (thread);
+      gdb_printf (fp, " thread %s", print_thread_id (thr));
+    }
 
   if (task != 0)
     gdb_printf (fp, " task %d", task);
diff --git a/gdb/testsuite/gdb.multi/bp-thread-specific.exp b/gdb/testsuite/gdb.multi/bp-thread-specific.exp
index 777fcf85ab0..6a7cd044af4 100644
--- a/gdb/testsuite/gdb.multi/bp-thread-specific.exp
+++ b/gdb/testsuite/gdb.multi/bp-thread-specific.exp
@@ -15,6 +15,9 @@
 
 # Check that GDB uses the correct thread-id when describing multiple
 # thread specific breakpoints at the same location.
+#
+# Also check that the correct thread-ids are used in the saved
+# breakpoints file.
 
 # The plain remote target can't do multiple inferiors.
 require !use_gdb_stub
@@ -59,3 +62,46 @@ gdb_test "break foo thread 1.1" \
 	 "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 $hex: foo\\. \\(2 locations\\)"]
+
+# Save the breakpoints into a file.
+if {[is_remote host]} {
+    set bps bps
+} else {
+    set bps [standard_output_file bps]
+}
+
+remote_file host delete "$bps"
+gdb_test "save breakpoint $bps" "" "save breakpoint to bps"
+
+if {[is_remote host]} {
+    set bps [remote_upload host bps [standard_output_file bps]]
+}
+
+# Now dig through the saved breakpoints file and check that the
+# thread-ids were written out correctly.  First open the saved
+# breakpoints and read them into a list.
+set fh [open $bps]
+set lines [split [read $fh] "\n"]
+close $fh
+
+# Except the list created from the saved breakpoints file will have a
+# blank line entry at the end, so remove it now.
+gdb_assert {[string equal [lindex $lines end] ""]} \
+    "check last item was an empty line"
+set lines [lrange $lines 0 end-1]
+
+# These are the lines we expect in the saved breakpoints file, in the
+# order that we expect them.  These are strings, not regexps.
+set expected_results \
+    [list \
+	 "break -qualified main" \
+	 "break foo thread 2.1" \
+	 "break foo thread 1.1"]
+
+# Now check that the files contents (in LINES) matches the
+# EXPECTED_RESULTS.
+gdb_assert {[llength $lines] == [llength $expected_results]} \
+    "correct number of lines in saved breakpoints file"
+foreach a $lines b $expected_results {
+    gdb_assert {[string equal $a $b]} "line '$b'"
+}
-- 
2.25.4