[PATCH 08/14] Remove the TUI register window rerender overload

[Tom Tromey <tom@tromey.com>]

After these restructurings, it should be clear that the rerender
overload can be removed from the TUI register window.  This is done by
moving a bit more logic from show_registers into update_register_data.
After this, update_register_data simply updates the internal state,
and rerender will write to the screen.  All the actual rendering work
is done, ultimately, by display_registers_from.  This split between
updating the mode and rendering makes it clear that the recursive case
can't happen any longer.
---
 gdb/tui/tui-regs.c | 55 ++++++++++++++++++++++++------------------------------
 gdb/tui/tui-regs.h | 14 ++++++--------
 2 files changed, 30 insertions(+), 39 deletions(-)

diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index 7b6b669fe51..5726dc3fea8 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -165,31 +165,33 @@ tui_data_window::first_reg_element_no_inline (int line_no) const
    and refresh the window.  */
 void
 tui_data_window::show_registers (const reggroup *group)
+{
+  update_register_data (group);
+  rerender ();
+}
+
+/* Set the data window to display the registers of the register group
+   using the given frame.  Values are refreshed only when
+   refresh_values_only is true.  */
+
+void
+tui_data_window::update_register_data (const reggroup *group)
 {
   if (group == nullptr)
     group = general_reggroup;
 
-  if (target_has_registers () && target_has_stack () && target_has_memory ())
-    update_register_data (group, get_selected_frame (nullptr));
-  else
+  if (!target_has_registers ()
+      || !target_has_stack ()
+      || !target_has_memory ())
     {
-      set_title (_("Registers"));
+      set_title ("");
       m_current_group = nullptr;
       m_regs_content.clear ();
+      return;
     }
 
-  rerender (false);
-}
-
-
-/* Set the data window to display the registers of the register group
-   using the given frame.  Values are refreshed only when
-   refresh_values_only is true.  */
+  frame_info_ptr frame = get_selected_frame (nullptr);
 
-void
-tui_data_window::update_register_data (const reggroup *group,
-				       frame_info_ptr frame)
-{
   m_current_group = group;
 
   /* Make a new title showing which group we display.  */
@@ -222,6 +224,9 @@ tui_data_window::update_register_data (const reggroup *group,
 void
 tui_data_window::display_registers_from (int start_element_no)
 {
+  werase (handle.get ());
+  check_and_display_highlight_if_needed ();
+
   /* In case the regs window is not boxed, we'll write the last char in the
      last line here, causing a scroll, so prevent that.  */
   scrollok (handle.get (), FALSE);
@@ -358,29 +363,18 @@ tui_data_window::erase_data_content (const char *prompt)
 	x_pos = half_width - strlen (prompt);
       display_string (height / 2, x_pos, prompt);
     }
-  tui_wrefresh (handle.get ());
 }
 
 /* See tui-regs.h.  */
 
 void
-tui_data_window::rerender (bool toplevel)
+tui_data_window::rerender ()
 {
   if (m_regs_content.empty ())
-    {
-      if (toplevel && has_stack_frames ())
-	{
-	  frame_info_ptr fi = get_selected_frame (NULL);
-	  check_register_values (fi);
-	}
-      else
-	erase_data_content (_("[ Register Values Unavailable ]"));
-    }
+    erase_data_content (_("[ Register Values Unavailable ]"));
   else
-    {
-      erase_data_content (NULL);
-      display_registers_from (0);
-    }
+    display_registers_from (0);
+  tui_wrefresh (handle.get ());
 }
 
 
@@ -402,7 +396,6 @@ tui_data_window::do_scroll_vertical (int num_to_scroll)
   if (first_line >= 0)
     {
       first_line += num_to_scroll;
-      erase_data_content (NULL);
       display_registers_from_line (first_line);
     }
 }
diff --git a/gdb/tui/tui-regs.h b/gdb/tui/tui-regs.h
index 701b8707947..b31a5a3e5b8 100644
--- a/gdb/tui/tui-regs.h
+++ b/gdb/tui/tui-regs.h
@@ -56,7 +56,10 @@ struct tui_register_info
 /* The TUI registers window.  */
 struct tui_data_window : public tui_win_info
 {
-  tui_data_window () = default;
+  tui_data_window ()
+  {
+    update_register_data (nullptr);
+  }
 
   DISABLE_COPY_AND_ASSIGN (tui_data_window);
 
@@ -81,11 +84,7 @@ struct tui_data_window : public tui_win_info
   {
   }
 
-  void rerender (bool toplevel);
-  void rerender () override
-  {
-    rerender (true);
-  }
+  void rerender () override;
 
 private:
 
@@ -110,8 +109,7 @@ struct tui_data_window : public tui_win_info
      display off the end of the register display.  */
   void display_reg_element_at_line (int start_element_no, int start_line_no);
 
-  void update_register_data (const reggroup *group,
-			     frame_info_ptr frame);
+  void update_register_data (const reggroup *group);
 
   /* Answer the number of the last line in the regs display.  If there
      are no registers (-1) is returned.  */

-- 
2.43.0