gdb/infrun: add reason parameter to stop_all_threads

Add a "reason" parameter, only used to show in debug messages what is
the reason for stopping all threads.  This helped me understand the
debug logs while adding some new uses of stop_all_threads, so I am
proposing to merge it.

Change-Id: I66c8c335ebf41836a7bc3d5fe1db92c195f65e55

4 files changed, 14 insertions, 11 deletions

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index fbae4e1..b76345d 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2521,7 +2521,7 @@ attach_post_wait (int from_tty, enum attach_post_wait_mode mode)
 	{
 	  struct thread_info *lowest = inferior_thread ();
 
-	  stop_all_threads ();
+	  stop_all_threads ("attaching");
 
 	  /* It's not defined which thread will report the attach
 	     stop.  For consistency, always select the thread with
diff --git a/gdb/infrun.c b/gdb/infrun.c
index dbd8277..12661b5 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2388,7 +2388,7 @@ resume_1 (enum gdb_signal sig)
 	  /* Fallback to stepping over the breakpoint in-line.  */
 
 	  if (target_is_non_stop_p ())
-	    stop_all_threads ();
+	    stop_all_threads ("displaced stepping falling back on inline stepping");
 
 	  set_step_over_info (regcache->aspace (),
 			      regcache_read_pc (regcache), 0, tp->global_num);
@@ -4904,7 +4904,7 @@ handle_one (const wait_one_event &event)
 /* See infrun.h.  */
 
 void
-stop_all_threads (void)
+stop_all_threads (const char *reason)
 {
   /* We may need multiple passes to discover all threads.  */
   int pass;
@@ -4912,7 +4912,7 @@ stop_all_threads (void)
 
   gdb_assert (exists_non_stop_target ());
 
-  infrun_debug_printf ("starting");
+  INFRUN_SCOPED_DEBUG_START_END ("reason=%s", reason);
 
   scoped_restore_current_thread restore_thread;
 
@@ -7957,7 +7957,7 @@ stop_waiting (struct execution_control_state *ecs)
   /* If all-stop, but there exists a non-stop target, stop all
      threads now that we're presenting the stop to the user.  */
   if (!non_stop && exists_non_stop_target ())
-    stop_all_threads ();
+    stop_all_threads ("presenting stop to user in all-stop");
 }
 
 /* Like keep_going, but passes the signal to the inferior, even if the
@@ -8057,7 +8057,7 @@ keep_going_pass_signal (struct execution_control_state *ecs)
 	 we're about to step over, otherwise other threads could miss
 	 it.  */
       if (step_over_info_valid_p () && target_is_non_stop_p ())
-	stop_all_threads ();
+	stop_all_threads ("starting in-line step-over");
 
       /* Stop stepping if inserting breakpoints fails.  */
       try
diff --git a/gdb/infrun.h b/gdb/infrun.h
index 1209b41..ecfb767 100644
--- a/gdb/infrun.h
+++ b/gdb/infrun.h
@@ -40,8 +40,8 @@ extern bool debug_infrun;
 
 /* Print "infrun" start/end debug statements.  */
 
-#define INFRUN_SCOPED_DEBUG_START_END(msg) \
-  scoped_debug_start_end (debug_infrun, "infrun", msg)
+#define INFRUN_SCOPED_DEBUG_START_END(fmt, ...) \
+  scoped_debug_start_end (debug_infrun, "infrun", fmt, ##__VA_ARGS__)
 
 /* Print "infrun" enter/exit debug statements.  */
 
@@ -138,8 +138,11 @@ extern void set_last_target_status (process_stratum_target *target, ptid_t ptid,
    target_wait().  */
 extern void nullify_last_target_wait_ptid ();
 
-/* Stop all threads.  Only returns after everything is halted.  */
-extern void stop_all_threads (void);
+/* Stop all threads.  Only returns after everything is halted.
+
+   REASON is a string indicating the reason why we stop all threads, used in
+   debug messages.  */
+extern void stop_all_threads (const char *reason);
 
 extern void prepare_for_detach (void);
 
diff --git a/gdb/remote.c b/gdb/remote.c
index bc308bd..3f06ba5 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -4642,7 +4642,7 @@ remote_target::process_initial_stop_replies (int from_tty)
 	gdb_assert (!this->is_async_p ());
 	SCOPE_EXIT { target_async (0); };
 	target_async (1);
-	stop_all_threads ();
+	stop_all_threads ("remote connect in all-stop");
       }
 
       /* If all threads of an inferior were already stopped, we