gdb: use infrun_debug_printf in print_target_wait_results

The code in print_target_wait_results uses a single call to debug_printf
in order to make sure a single timestamp is emitted, despite printing
multiple lines.  The result is:

    941502.043284 [infrun] target_wait (-1.0.0, status) =
    [infrun]   649832.649832.0 [process 649832],
    [infrun]   status->kind = stopped, signal = GDB_SIGNAL_TRAP

I find this decision a bit counter productive, because it messes up the
alignment of the three lines.  We don't care that three (slightly
different) timestamps are printed.

I suggest to change this function to use infrun_debug_printf, with this
result:

    941601.425771 [infrun] print_target_wait_results: target_wait (-1.0.0 [process -1], status) =
    941601.425824 [infrun] print_target_wait_results:   651481.651481.0 [process 651481],
    941601.425867 [infrun] print_target_wait_results:   status->kind = stopped, signal = GDB_SIGNAL_TRAP

Note that the current code only prints the waiton_ptid as a string
between square brackets if pid != -1.  I don't think this complexity is
needed in a debug print.  I made it so it's always printed, which I
think results in a much simpler function.

gdb/ChangeLog:

	* infrun.c (print_target_wait_results): Use infrun_debug_printf.

Change-Id: I817bd10286b8e641a6c751ac3a1bd1ddf9b18ce0

2 files changed, 15 insertions, 25 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e0da11f..674c396 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,9 @@
 2021-01-04  Simon Marchi  <simon.marchi@efficios.com>
 
+	* infrun.c (print_target_wait_results): Use infrun_debug_printf.
+
+2021-01-04  Simon Marchi  <simon.marchi@efficios.com>
+
 	* utils.c (vfprintf_unfiltered): Print timestamp only when
 	previous debug output ended with a newline.
 
diff --git a/gdb/infrun.c b/gdb/infrun.c
index bb73871..01d7ead 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3275,31 +3275,17 @@ void
 print_target_wait_results (ptid_t waiton_ptid, ptid_t result_ptid,
 			   const struct target_waitstatus *ws)
 {
-  std::string status_string = target_waitstatus_to_string (ws);
-  string_file stb;
-
-  /* The text is split over several lines because it was getting too long.
-     Call fprintf_unfiltered (gdb_stdlog) once so that the text is still
-     output as a unit; we want only one timestamp printed if debug_timestamp
-     is set.  */
-
-  stb.printf ("[infrun] target_wait (%d.%ld.%ld",
-	      waiton_ptid.pid (),
-	      waiton_ptid.lwp (),
-	      waiton_ptid.tid ());
-  if (waiton_ptid.pid () != -1)
-    stb.printf (" [%s]", target_pid_to_str (waiton_ptid).c_str ());
-  stb.printf (", status) =\n");
-  stb.printf ("[infrun]   %d.%ld.%ld [%s],\n",
-	      result_ptid.pid (),
-	      result_ptid.lwp (),
-	      result_ptid.tid (),
-	      target_pid_to_str (result_ptid).c_str ());
-  stb.printf ("[infrun]   %s\n", status_string.c_str ());
-
-  /* This uses %s in part to handle %'s in the text, but also to avoid
-     a gcc error: the format attribute requires a string literal.  */
-  fprintf_unfiltered (gdb_stdlog, "%s", stb.c_str ());
+  infrun_debug_printf ("target_wait (%d.%ld.%ld [%s], status) =",
+		       waiton_ptid.pid (),
+		       waiton_ptid.lwp (),
+		       waiton_ptid.tid (),
+		       target_pid_to_str (waiton_ptid).c_str ());
+  infrun_debug_printf ("  %d.%ld.%ld [%s],",
+		       result_ptid.pid (),
+		       result_ptid.lwp (),
+		       result_ptid.tid (),
+		       target_pid_to_str (result_ptid).c_str ());
+  infrun_debug_printf ("  %s", target_waitstatus_to_string (ws).c_str ());
 }
 
 /* Select a thread at random, out of those which are resumed and have