Replace finish_thread_state_cleanup with a RAII class

gdb/ChangeLog:
2018-04-10  Pedro Alves  <palves@redhat.com>

	* gdbthread.h (finish_thread_state_cleanup): Delete declaration.
	(scoped_finish_thread_state): New class.
	* infcmd.c (run_command_1): Use it instead of finish_thread_state
	cleanup.
	* infrun.c (proceed, prepare_for_detach, wait_for_inferior)
	(fetch_inferior_event, normal_stop): Likewise.
	* thread.c (finish_thread_state_cleanup): Delete.

5 files changed, 63 insertions, 50 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 09d8db4..d46ecdd 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2018-04-10  Pedro Alves  <palves@redhat.com>
+
+	* gdbthread.h (finish_thread_state_cleanup): Delete declaration.
+	(scoped_finish_thread_state): New class.
+	* infcmd.c (run_command_1): Use it instead of finish_thread_state
+	cleanup.
+	* infrun.c (proceed, prepare_for_detach, wait_for_inferior)
+	(fetch_inferior_event, normal_stop): Likewise.
+	* thread.c (finish_thread_state_cleanup): Delete.
+
 2018-04-09  Simon Marchi  <simon.marchi@polymtl.ca>
 	    Pedro Alves  <palves@redhat.com>
 
diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index 9b468db..09ea5ba 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -567,10 +567,33 @@ extern int threads_are_executing (void);
    Notifications are only emitted if the thread state did change.  */
 extern void finish_thread_state (ptid_t ptid);
 
-/* Same as FINISH_THREAD_STATE, but with an interface suitable to be
-   registered as a cleanup.  PTID_P points to the ptid_t that is
-   passed to FINISH_THREAD_STATE.  */
-extern void finish_thread_state_cleanup (void *ptid_p);
+/* Calls finish_thread_state on scope exit, unless release() is called
+   to disengage.  */
+class scoped_finish_thread_state
+{
+public:
+  explicit scoped_finish_thread_state (ptid_t ptid)
+    : m_ptid (ptid)
+  {}
+
+  ~scoped_finish_thread_state ()
+  {
+    if (!m_released)
+      finish_thread_state (m_ptid);
+  }
+
+  /* Disengage.  */
+  void release ()
+  {
+    m_released = true;
+  }
+
+  DISABLE_COPY_AND_ASSIGN (scoped_finish_thread_state);
+
+private:
+  bool m_released = false;
+  ptid_t m_ptid;
+};
 
 /* Commands with a prefix of `thread'.  */
 extern struct cmd_list_element *thread_cmd_list;
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 9c236b8..d43e7f2 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -565,8 +565,6 @@ static void
 run_command_1 (const char *args, int from_tty, enum run_how run_how)
 {
   const char *exec_file;
-  struct cleanup *old_chain;
-  ptid_t ptid;
   struct ui_out *uiout = current_uiout;
   struct target_ops *run_target;
   int async_exec;
@@ -655,11 +653,10 @@ run_command_1 (const char *args, int from_tty, enum run_how run_how)
      events --- the frontend shouldn't see them as stopped.  In
      all-stop, always finish the state of all threads, as we may be
      resuming more than just the new process.  */
-  if (non_stop)
-    ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
-  else
-    ptid = minus_one_ptid;
-  old_chain = make_cleanup (finish_thread_state_cleanup, &ptid);
+  ptid_t finish_ptid = (non_stop
+			? ptid_t (current_inferior ()->pid)
+			: minus_one_ptid);
+  scoped_finish_thread_state finish_state (finish_ptid);
 
   /* Pass zero for FROM_TTY, because at this point the "run" command
      has done its thing; now we are setting up the running program.  */
@@ -680,7 +677,7 @@ run_command_1 (const char *args, int from_tty, enum run_how run_how)
 
   /* Since there was no error, there's no need to finish the thread
      states here.  */
-  discard_cleanups (old_chain);
+  finish_state.release ();
 }
 
 static void
diff --git a/gdb/infrun.c b/gdb/infrun.c
index d89f813..c1db689 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2979,7 +2979,6 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
   ptid_t resume_ptid;
   struct execution_control_state ecss;
   struct execution_control_state *ecs = &ecss;
-  struct cleanup *old_chain;
   int started;
 
   /* If we're stopped at a fork/vfork, follow the branch set by the
@@ -3043,7 +3042,7 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
   /* If an exception is thrown from this point on, make sure to
      propagate GDB's knowledge of the executing state to the
      frontend/user running state.  */
-  old_chain = make_cleanup (finish_thread_state_cleanup, &resume_ptid);
+  scoped_finish_thread_state finish_state (resume_ptid);
 
   /* Even if RESUME_PTID is a wildcard, and we end up resuming fewer
      threads (e.g., we might need to set threads stepping over
@@ -3198,7 +3197,7 @@ proceed (CORE_ADDR addr, enum gdb_signal siggnal)
 
   target_commit_resume ();
 
-  discard_cleanups (old_chain);
+  finish_state.release ();
 
   /* Tell the event loop to wait for it to stop.  If the target
      supports asynchronous execution, it'll do this from within
@@ -3641,7 +3640,6 @@ prepare_for_detach (void)
 
   while (!ptid_equal (displaced->step_ptid, null_ptid))
     {
-      struct cleanup *old_chain_2;
       struct execution_control_state ecss;
       struct execution_control_state *ecs;
 
@@ -3663,14 +3661,13 @@ prepare_for_detach (void)
       /* If an error happens while handling the event, propagate GDB's
 	 knowledge of the executing state to the frontend/user running
 	 state.  */
-      old_chain_2 = make_cleanup (finish_thread_state_cleanup,
-				  &minus_one_ptid);
+      scoped_finish_thread_state finish_state (minus_one_ptid);
 
       /* Now figure out what to do with the result of the result.  */
       handle_inferior_event (ecs);
 
       /* No error, don't finish the state yet.  */
-      discard_cleanups (old_chain_2);
+      finish_state.release ();
 
       /* Breakpoints and watchpoints are not installed on the target
 	 at this point, and signals are passed directly to the
@@ -3696,7 +3693,6 @@ void
 wait_for_inferior (void)
 {
   struct cleanup *old_cleanups;
-  struct cleanup *thread_state_chain;
 
   if (debug_infrun)
     fprintf_unfiltered
@@ -3709,7 +3705,7 @@ wait_for_inferior (void)
   /* If an error happens while handling the event, propagate GDB's
      knowledge of the executing state to the frontend/user running
      state.  */
-  thread_state_chain = make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
+  scoped_finish_thread_state finish_state (minus_one_ptid);
 
   while (1)
     {
@@ -3740,7 +3736,7 @@ wait_for_inferior (void)
     }
 
   /* No error, don't finish the state yet.  */
-  discard_cleanups (thread_state_chain);
+  finish_state.release ();
 
   do_cleanups (old_cleanups);
 }
@@ -3859,7 +3855,6 @@ fetch_inferior_event (void *client_data)
   struct execution_control_state ecss;
   struct execution_control_state *ecs = &ecss;
   struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
-  struct cleanup *ts_old_chain;
   int cmd_done = 0;
   ptid_t waiton_ptid = minus_one_ptid;
 
@@ -3912,14 +3907,12 @@ fetch_inferior_event (void *client_data)
   /* If an error happens while handling the event, propagate GDB's
      knowledge of the executing state to the frontend/user running
      state.  */
-  if (!target_is_non_stop_p ())
-    ts_old_chain = make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
-  else
-    ts_old_chain = make_cleanup (finish_thread_state_cleanup, &ecs->ptid);
+  ptid_t finish_ptid = !target_is_non_stop_p () ? minus_one_ptid : ecs->ptid;
+  scoped_finish_thread_state finish_state (finish_ptid);
 
   /* Get executed before make_cleanup_restore_current_thread above to apply
      still for the thread which has thrown the exception.  */
-  make_bpstat_clear_actions_cleanup ();
+  struct cleanup *ts_old_chain = make_bpstat_clear_actions_cleanup ();
 
   make_cleanup (delete_just_stopped_threads_infrun_breakpoints_cleanup, NULL);
 
@@ -3974,9 +3967,11 @@ fetch_inferior_event (void *client_data)
 	}
     }
 
-  /* No error, don't finish the thread states yet.  */
   discard_cleanups (ts_old_chain);
 
+  /* No error, don't finish the thread states yet.  */
+  finish_state.release ();
+
   /* Revert thread and frame.  */
   do_cleanups (old_chain);
 
@@ -8165,8 +8160,6 @@ normal_stop (void)
 {
   struct target_waitstatus last;
   ptid_t last_ptid;
-  struct cleanup *old_chain = make_cleanup (null_cleanup, NULL);
-  ptid_t pid_ptid;
 
   get_last_target_status (&last_ptid, &last);
 
@@ -8176,8 +8169,11 @@ normal_stop (void)
      propagate GDB's knowledge of the executing state to the
      frontend/user running state.  A QUIT is an easy exception to see
      here, so do this before any filtered output.  */
+
+  gdb::optional<scoped_finish_thread_state> maybe_finish_thread_state;
+
   if (!non_stop)
-    make_cleanup (finish_thread_state_cleanup, &minus_one_ptid);
+    maybe_finish_thread_state.emplace (minus_one_ptid);
   else if (last.kind == TARGET_WAITKIND_SIGNALLED
 	   || last.kind == TARGET_WAITKIND_EXITED)
     {
@@ -8186,14 +8182,11 @@ normal_stop (void)
 	 "checkpoint", when the current checkpoint/fork exits,
 	 linux-fork.c automatically switches to another fork from
 	 within target_mourn_inferior.  */
-      if (!ptid_equal (inferior_ptid, null_ptid))
-	{
-	  pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
-	  make_cleanup (finish_thread_state_cleanup, &pid_ptid);
-	}
+      if (inferior_ptid != null_ptid)
+	maybe_finish_thread_state.emplace (ptid_t (inferior_ptid.pid ()));
     }
   else if (last.kind != TARGET_WAITKIND_NO_RESUMED)
-    make_cleanup (finish_thread_state_cleanup, &inferior_ptid);
+    maybe_finish_thread_state.emplace (inferior_ptid);
 
   /* As we're presenting a stop, and potentially removing breakpoints,
      update the thread list so we can tell whether there are threads
@@ -8225,7 +8218,7 @@ normal_stop (void)
      after this event is handled, so we're not really switching, only
      informing of a stop.  */
   if (!non_stop
-      && !ptid_equal (previous_inferior_ptid, inferior_ptid)
+      && previous_inferior_ptid != inferior_ptid
       && target_has_execution
       && last.kind != TARGET_WAITKIND_SIGNALLED
       && last.kind != TARGET_WAITKIND_EXITED
@@ -8266,7 +8259,7 @@ normal_stop (void)
     }
 
   /* Let the user/frontend see the threads as stopped.  */
-  do_cleanups (old_chain);
+  maybe_finish_thread_state.reset ();
 
   /* Select innermost stack frame - i.e., current frame is frame 0,
      and current location is based on that.  Handle the case where the
diff --git a/gdb/thread.c b/gdb/thread.c
index 99f3f5b..c1a8174 100644
--- a/gdb/thread.c
+++ b/gdb/thread.c
@@ -1040,16 +1040,6 @@ finish_thread_state (ptid_t ptid)
     gdb::observers::target_resumed.notify (ptid);
 }
 
-void
-finish_thread_state_cleanup (void *arg)
-{
-  ptid_t *ptid_p = (ptid_t *) arg;
-
-  gdb_assert (arg);
-
-  finish_thread_state (*ptid_p);
-}
-
 /* See gdbthread.h.  */
 
 void