gdb: add some extra debug information to attach_command

While working on another patch I wanted to add some extra debug
information to the attach_command function.  This required me to add a
new function to convert the thread_info::state variable to a string.

The new debug might be useful to others, and the state to string
function might be useful in other locations, so I thought I'd merge
it.

3 files changed, 36 insertions, 0 deletions

diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index 5350a42f1b..9921dae7a7 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -1003,4 +1003,8 @@ extern void thread_try_catch_cmd (thread_info *thr,
 				  const char *cmd, int from_tty,
 				  const qcs_flags &flags);
 
+/* Return a string representation of STATE.  */
+
+extern const char *thread_state_string (enum thread_state state);
+
 #endif /* GDBTHREAD_H */
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 8bf58018bd..9f4ed8bff1 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2541,6 +2541,18 @@ attach_command (const char *args, int from_tty)
      shouldn't refer to attach_target again.  */
   attach_target = NULL;
 
+  if (debug_infrun)
+    {
+      infrun_debug_printf ("immediately after attach:");
+      for (thread_info *thread : inferior->non_exited_threads ())
+	infrun_debug_printf ("  thread %s, executing = %d, resumed = %d, "
+			     "state = %s",
+			     thread->ptid.to_string ().c_str (),
+			     thread->executing (),
+			     thread->resumed (),
+			     thread_state_string (thread->state));
+    }
+
   /* Set up the "saved terminal modes" of the inferior
      based on what modes we are starting it with.  */
   target_terminal::init ();
diff --git a/gdb/thread.c b/gdb/thread.c
index 8a7d142bab..c43f661314 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -2050,6 +2050,26 @@ thread_name (thread_info *thread)
   return target_thread_name (thread);
 }
 
+/* See gdbthread.h.  */
+
+const char *
+thread_state_string (enum thread_state state)
+{
+  switch (state)
+    {
+    case THREAD_STOPPED:
+      return "STOPPED";
+
+    case THREAD_RUNNING:
+      return "RUNNING";
+
+    case THREAD_EXITED:
+      return "EXITED";
+    }
+
+  gdb_assert_not_reached ("unknown thread state");
+}
+
 /* Return a new value for the selected thread's id.  Return a value of
    0 if no thread is selected.  If GLOBAL is true, return the thread's
    global number.  Otherwise return the per-inferior number.  */