Remove unnecessary casts of NULL

I noticed some unnecessary casts of NULL.  This removes all the
unnecessary ones, leaving only ones where we must ensure that NULL has
pointer type for passing through varargs.

I removed a couple of useless casts of 0 that I noticed while writing
this.

Tested by rebuilding.

gdb/ChangeLog
2019-06-16  Tom Tromey  <tom@tromey.com>

	* valops.c (value_cast, value_slice): Remove unnecessary cast.
	* breakpoint.c (stopin_command, stopat_command)
	(until_break_command, decode_location_default): Remove unnecessary
	cast.
	* utils.c (subset_compare): Remove unnecessary cast.
	* ada-lang.c (ada_update_initial_language): Remove unnecessary
	cast.
	* linespec.c (decode_line_with_last_displayed): Remove unnecessary
	cast.
	* infcmd.c (path_command): Remove unnecessary cast.
	* coffread.c (decode_type): Remove unnecessary cast.
	* xcoffread.c (read_xcoff_symtab): Remove unnecessary cast.
	* mipsread.c (mipscoff_symfile_read): Remove unnecessary cast.
	* tui/tui-stack.c (tui_show_locator_content)
	(tui_show_frame_info): Remove unnecessary cast.
	* tui/tui-win.c (tui_scroll_forward_command)
	(tui_scroll_backward_command, tui_set_focus, tui_set_win_height)
	(parse_scrolling_args): Remove unnecessary cast.
	* tui/tui-data.c (init_win_info, tui_del_window)
	(tui_free_window, tui_del_data_windows, tui_free_data_content)
	(free_content_elements): Remove unnecessary cast.
	* tui/tui-windata.c (tui_first_data_item_displayed): Remove
	unnecessary cast.
	* tui/tui-source.c (tui_set_source_content)
	(tui_vertical_source_scroll): Remove unnecessary cast.
	* tui/tui-layout.c (tui_default_win_height): Remove unnecessary
	cast.
	* tui/tui-io.c (tui_initialize_io): Remove unnecessary cast.
	* tui/tui-regs.c (tui_display_registers_from)
	(tui_display_register): Remove unnecessary cast.
	* tui/tui-wingeneral.c (tui_refresh_win, tui_delete_win)
	(tui_unhighlight_win, tui_highlight_win, tui_make_window)
	(make_visible): Remove unnecessary cast.
	* tui/tui-winsource.c (tui_erase_source_content)
	(tui_update_breakpoint_info, tui_set_exec_info_content): Remove
	unnecessary cast.
	* ax-gdb.c (agent_command_1): Remove unnecessary cast.
	* cli/cli-setshow.c (cmd_show_list): Remove unnecessary cast.
	* stabsread.c (read_type, read_array_type, read_range_type):
	Remove unnecessary cast.
	* mdebugread.c (mdebug_build_psymtabs): Remove unnecessary cast.
	(parse_symbol, parse_type, upgrade_type, parse_external)
	(parse_partial_symbols, psymtab_to_symtab_1, cross_ref): Remove
	unnecessary cast.
	* gdb_bfd.c (gdb_bfd_map_section): Remove unnecessary cast.

10 files changed, 34 insertions, 39 deletions

diff --git a/gdb/tui/tui-data.c b/gdb/tui/tui-data.c
index 7c14305..35eae4f 100644
--- a/gdb/tui/tui-data.c
+++ b/gdb/tui/tui-data.c
@@ -507,8 +507,7 @@ init_win_info (struct tui_win_info *win_info)
     {
     case SRC_WIN:
     case DISASSEM_WIN:
-      win_info->detail.source_info.execution_info
-	= (struct tui_gen_win_info *) NULL;
+      win_info->detail.source_info.execution_info = NULL;
       win_info->detail.source_info.has_locator = FALSE;
       win_info->detail.source_info.horizontal_offset = 0;
       win_info->detail.source_info.gdbarch = NULL;
@@ -620,7 +619,7 @@ tui_del_window (struct tui_win_info *win_info)
     case SRC_WIN:
     case DISASSEM_WIN:
       generic_win = tui_locator_win_info_ptr ();
-      if (generic_win != (struct tui_gen_win_info *) NULL)
+      if (generic_win != NULL)
 	{
 	  tui_delete_win (generic_win->handle);
 	  generic_win->handle = NULL;
@@ -632,7 +631,7 @@ tui_del_window (struct tui_win_info *win_info)
           win_info->detail.source_info.fullname = NULL;
         }
       generic_win = win_info->detail.source_info.execution_info;
-      if (generic_win != (struct tui_gen_win_info *) NULL)
+      if (generic_win != NULL)
 	{
 	  tui_delete_win (generic_win->handle);
 	  generic_win->handle = NULL;
@@ -651,7 +650,7 @@ tui_del_window (struct tui_win_info *win_info)
     default:
       break;
     }
-  if (win_info->generic.handle != (WINDOW *) NULL)
+  if (win_info->generic.handle != NULL)
     {
       tui_delete_win (win_info->generic.handle);
       win_info->generic.handle = NULL;
@@ -675,7 +674,7 @@ tui_free_window (struct tui_win_info *win_info)
           win_info->detail.source_info.fullname = NULL;
         }
       generic_win = win_info->detail.source_info.execution_info;
-      if (generic_win != (struct tui_gen_win_info *) NULL)
+      if (generic_win != NULL)
 	{
 	  tui_delete_win (generic_win->handle);
 	  generic_win->handle = NULL;
@@ -704,7 +703,7 @@ tui_free_window (struct tui_win_info *win_info)
     default:
       break;
     }
-  if (win_info->generic.handle != (WINDOW *) NULL)
+  if (win_info->generic.handle != NULL)
     {
       tui_delete_win (win_info->generic.handle);
       win_info->generic.handle = NULL;
@@ -762,7 +761,7 @@ tui_del_data_windows (tui_win_content content,
       struct tui_gen_win_info *generic_win
 	= &content[i]->which_element.data_window;
 
-      if (generic_win != (struct tui_gen_win_info *) NULL)
+      if (generic_win != NULL)
 	{
 	  tui_delete_win (generic_win->handle);
 	  generic_win->handle = NULL;
@@ -786,7 +785,7 @@ tui_free_data_content (tui_win_content content,
       struct tui_gen_win_info *generic_win
 	= &content[i]->which_element.data_window;
 
-      if (generic_win != (struct tui_gen_win_info *) NULL)
+      if (generic_win != NULL)
 	{
 	  tui_delete_win (generic_win->handle);
 	  generic_win->handle = NULL;
@@ -840,7 +839,7 @@ free_content_elements (tui_win_content content,
 	      struct tui_win_element *element;
 
 	      element = content[i];
-	      if (element != (struct tui_win_element *) NULL)
+	      if (element != NULL)
 		{
 		  switch (type)
 		    {
diff --git a/gdb/tui/tui-io.c b/gdb/tui/tui-io.c
index ad47c82..31c1c76 100644
--- a/gdb/tui/tui-io.c
+++ b/gdb/tui/tui-io.c
@@ -878,7 +878,7 @@ tui_initialize_io (void)
   if (tui_rl_outstream == 0)
     error (_("Cannot redirect readline output"));
 
-  setvbuf (tui_rl_outstream, (char*) NULL, _IOLBF, 0);
+  setvbuf (tui_rl_outstream, NULL, _IOLBF, 0);
 
 #ifdef O_NONBLOCK
   (void) fcntl (tui_readline_pipe[0], F_SETFL, O_NONBLOCK);
diff --git a/gdb/tui/tui-layout.c b/gdb/tui/tui-layout.c
index da50ced..bcae819 100644
--- a/gdb/tui/tui-layout.c
+++ b/gdb/tui/tui-layout.c
@@ -300,7 +300,7 @@ tui_default_win_height (enum tui_win_type type,
 {
   int h;
 
-  if (tui_win_list[type] != (struct tui_win_info *) NULL)
+  if (tui_win_list[type] != NULL)
     h = tui_win_list[type]->generic.height;
   else
     {
diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
index e6aeedd..dcfc433 100644
--- a/gdb/tui/tui-regs.c
+++ b/gdb/tui/tui-regs.c
@@ -358,7 +358,7 @@ tui_display_registers_from (int start_element_no)
 	      data_item_win = &display_info->regs_content[i]
                 ->which_element.data_window;
 	      data_element_ptr = &data_item_win->content[0]->which_element.data;
-              if (data_item_win->handle != (WINDOW*) NULL
+              if (data_item_win->handle != NULL
                   && (data_item_win->height != 1
                       || data_item_win->width != item_win_width
                       || data_item_win->origin.x != (item_win_width * j) + 1
@@ -368,7 +368,7 @@ tui_display_registers_from (int start_element_no)
                   data_item_win->handle = 0;
                 }
                   
-	      if (data_item_win->handle == (WINDOW *) NULL)
+	      if (data_item_win->handle == NULL)
 		{
 		  data_item_win->height = 1;
 		  data_item_win->width = item_win_width;
@@ -520,7 +520,7 @@ static void
 tui_display_register (struct tui_data_element *data,
                       struct tui_gen_win_info *win_info)
 {
-  if (win_info->handle != (WINDOW *) NULL)
+  if (win_info->handle != NULL)
     {
       int i;
 
diff --git a/gdb/tui/tui-source.c b/gdb/tui/tui-source.c
index 1fa0e98..5066c7d 100644
--- a/gdb/tui/tui-source.c
+++ b/gdb/tui/tui-source.c
@@ -129,7 +129,7 @@ tui_set_source_content (struct symtab *s,
 {
   enum tui_status ret = TUI_FAILURE;
 
-  if (s != (struct symtab *) NULL)
+  if (s != NULL)
     {
       int line_width, nlines;
 
@@ -319,7 +319,7 @@ tui_vertical_source_scroll (enum tui_scroll_direction scroll_direction,
       tui_win_content content = TUI_SRC_WIN->generic.content;
       struct symtab_and_line cursal = get_current_source_symtab_and_line ();
 
-      if (cursal.symtab == (struct symtab *) NULL)
+      if (cursal.symtab == NULL)
 	s = find_pc_line_symtab (get_frame_pc (get_selected_frame (NULL)));
       else
 	s = cursal.symtab;
diff --git a/gdb/tui/tui-stack.c b/gdb/tui/tui-stack.c
index 79f1f6f..b7e7ae8 100644
--- a/gdb/tui/tui-stack.c
+++ b/gdb/tui/tui-stack.c
@@ -250,7 +250,7 @@ tui_show_locator_content (void)
 
   locator = tui_locator_win_info_ptr ();
 
-  if (locator != NULL && locator->handle != (WINDOW *) NULL)
+  if (locator != NULL && locator->handle != NULL)
     {
       struct tui_win_element *element;
 
@@ -414,8 +414,7 @@ tui_show_frame_info (struct frame_info *fi)
 	  else
 	    {
 	      if (find_pc_partial_function (get_frame_pc (fi),
-					    (const char **) NULL,
-					    &low, NULL) == 0)
+					    NULL, &low, NULL) == 0)
 		{
 		  /* There is no symbol available for current PC.  There is no
 		     safe way how to "disassemble backwards".  */
diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c
index 575620f..a1329e5 100644
--- a/gdb/tui/tui-win.c
+++ b/gdb/tui/tui-win.c
@@ -877,7 +877,7 @@ tui_scroll_forward_command (const char *arg, int from_tty)
   /* Make sure the curses mode is enabled.  */
   tui_enable ();
   if (arg == NULL)
-    parse_scrolling_args (arg, &win_to_scroll, (int *) NULL);
+    parse_scrolling_args (arg, &win_to_scroll, NULL);
   else
     parse_scrolling_args (arg, &win_to_scroll, &num_to_scroll);
   tui_scroll (FORWARD_SCROLL, win_to_scroll, num_to_scroll);
@@ -893,7 +893,7 @@ tui_scroll_backward_command (const char *arg, int from_tty)
   /* Make sure the curses mode is enabled.  */
   tui_enable ();
   if (arg == NULL)
-    parse_scrolling_args (arg, &win_to_scroll, (int *) NULL);
+    parse_scrolling_args (arg, &win_to_scroll, NULL);
   else
     parse_scrolling_args (arg, &win_to_scroll, &num_to_scroll);
   tui_scroll (BACKWARD_SCROLL, win_to_scroll, num_to_scroll);
@@ -946,8 +946,7 @@ tui_set_focus (const char *arg, int from_tty)
       else
 	win_info = tui_partial_win_by_name (buf_ptr);
 
-      if (win_info == (struct tui_win_info *) NULL
-	  || !win_info->generic.is_visible)
+      if (win_info == NULL || !win_info->generic.is_visible)
 	warning (_("Invalid window specified. \n\
 The window name specified must be valid and visible.\n"));
       else
@@ -1116,8 +1115,7 @@ tui_set_win_height (const char *arg, int from_tty)
 	    wname[i] = tolower (wname[i]);
 	  win_info = tui_partial_win_by_name (wname);
 
-	  if (win_info == (struct tui_win_info *) NULL
-	      || !win_info->generic.is_visible)
+	  if (win_info == NULL || !win_info->generic.is_visible)
 	    warning (_("Invalid window specified. \n\
 The window name specified must be valid and visible.\n"));
 	  else
@@ -1634,7 +1632,7 @@ parse_scrolling_args (const char *arg,
 	  
 	  *win_to_scroll = tui_partial_win_by_name (wname);
 
-	  if (*win_to_scroll == (struct tui_win_info *) NULL
+	  if (*win_to_scroll == NULL
 	      || !(*win_to_scroll)->generic.is_visible)
 	    error (_("Invalid window specified. \n\
 The window name specified must be valid and visible.\n"));
diff --git a/gdb/tui/tui-windata.c b/gdb/tui/tui-windata.c
index 1bab39f..6f150c9 100644
--- a/gdb/tui/tui-windata.c
+++ b/gdb/tui/tui-windata.c
@@ -55,7 +55,7 @@ tui_first_data_item_displayed (void)
 
       data_item_win
 	= &TUI_DATA_WIN->generic.content[i]->which_element.data_window;
-      if (data_item_win->handle != (WINDOW *) NULL 
+      if (data_item_win->handle != NULL 
 	  && data_item_win->is_visible)
 	element_no = i;
     }
diff --git a/gdb/tui/tui-wingeneral.c b/gdb/tui/tui-wingeneral.c
index b1ed0f4..b474aa0 100644
--- a/gdb/tui/tui-wingeneral.c
+++ b/gdb/tui/tui-wingeneral.c
@@ -45,7 +45,7 @@ tui_refresh_win (struct tui_gen_win_info *win_info)
 
 	  data_item_win_ptr = &win_info->content[i]->which_element.data_window;
 	  if (data_item_win_ptr != NULL
-	      && data_item_win_ptr->handle != (WINDOW *) NULL)
+	      && data_item_win_ptr->handle != NULL)
 	    wrefresh (data_item_win_ptr->handle);
 	}
     }
@@ -55,7 +55,7 @@ tui_refresh_win (struct tui_gen_win_info *win_info)
     }
   else
     {
-      if (win_info->handle != (WINDOW *) NULL)
+      if (win_info->handle != NULL)
 	wrefresh (win_info->handle);
     }
 
@@ -67,7 +67,7 @@ tui_refresh_win (struct tui_gen_win_info *win_info)
 void
 tui_delete_win (WINDOW *window)
 {
-  if (window != (WINDOW *) NULL)
+  if (window != NULL)
     delwin (window);
 
   return;
@@ -110,7 +110,7 @@ void
 tui_unhighlight_win (struct tui_win_info *win_info)
 {
   if (win_info != NULL 
-      && win_info->generic.handle != (WINDOW *) NULL)
+      && win_info->generic.handle != NULL)
     {
       box_win ((struct tui_gen_win_info *) win_info, NO_HILITE);
       wrefresh (win_info->generic.handle);
@@ -124,7 +124,7 @@ tui_highlight_win (struct tui_win_info *win_info)
 {
   if (win_info != NULL
       && win_info->can_highlight
-      && win_info->generic.handle != (WINDOW *) NULL)
+      && win_info->generic.handle != NULL)
     {
       box_win ((struct tui_gen_win_info *) win_info, HILITE);
       wrefresh (win_info->generic.handle);
@@ -157,7 +157,7 @@ tui_make_window (struct tui_gen_win_info *win_info, int box_it)
 		   win_info->origin.y,
 		   win_info->origin.x);
   win_info->handle = handle;
-  if (handle != (WINDOW *) NULL)
+  if (handle != NULL)
     {
       if (box_it == BOX_WINDOW)
 	box_win (win_info, NO_HILITE);
@@ -189,7 +189,7 @@ make_visible (struct tui_gen_win_info *win_info, int visible)
     }
   else if (!visible
 	   && win_info->is_visible
-	   && win_info->handle != (WINDOW *) NULL)
+	   && win_info->handle != NULL)
     {
       win_info->is_visible = FALSE;
       tui_delete_win (win_info->handle);
diff --git a/gdb/tui/tui-winsource.c b/gdb/tui/tui-winsource.c
index e31a016..eab422d 100644
--- a/gdb/tui/tui-winsource.c
+++ b/gdb/tui/tui-winsource.c
@@ -235,7 +235,7 @@ tui_erase_source_content (struct tui_win_info *win_info,
   int x_pos;
   int half_width = (win_info->generic.width - 2) / 2;
 
-  if (win_info->generic.handle != (WINDOW *) NULL)
+  if (win_info->generic.handle != NULL)
     {
       werase (win_info->generic.handle);
       tui_check_and_display_highlight_if_needed (win_info);
@@ -453,7 +453,7 @@ tui_update_breakpoint_info (struct tui_win_info *win,
          those that we already hit.  */
       mode = 0;
       for (bp = breakpoint_chain;
-           bp != (struct breakpoint *) NULL;
+           bp != NULL;
            bp = bp->next)
         {
 	  struct bp_location *loc;
@@ -504,8 +504,7 @@ tui_set_exec_info_content (struct tui_win_info *win_info)
 {
   enum tui_status ret = TUI_SUCCESS;
 
-  if (win_info->detail.source_info.execution_info
-      != (struct tui_gen_win_info *) NULL)
+  if (win_info->detail.source_info.execution_info != NULL)
     {
       struct tui_gen_win_info *exec_info_ptr
 	= win_info->detail.source_info.execution_info;