Fix help popups for Athena menus

* lwlib/lwlib-widget.h (struct _widget_value): Use a gc_handle for the
help field.
* lwlib/lwlib.c (free_widget_value_tree, copy_widget_value_tree)
(merge_widget_value): Adapt to gc_handles.
* src/gc-handles.h (gc_handle_for_gc_handle, gc_handle_assign): New
helpers.
* src/gc-handles.c (gc_handle_for_gc_handle, gc_handle_assign):
Implementation.
* src/menu.c (make_widget_value, free_menubar_widget_value_tree): Adapt
to gc_handles.
* src/xmenu.c (menu_highlight_callback): Adapt to gc_handles.
* src/gtkutil.c (make_menu_item, xg_create_one_menuitem)
(xg_update_menu_item): Adapted to changed widget_value.

lwlib/lwlib-widget.h

@@ -24,6 +24,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #define LWLIB_WIDGET_H
 
 #include "../src/lisp.h"
+#include "../src/gc-handles.h"
 
 typedef enum
 {
@@ -53,10 +54,8 @@ typedef struct _widget_value
   Lisp_Object lkey;
   char *key;
 
-  /* Help string or nil if none.
-     GC finds this string through the frame's menu_bar_vector
-     or through menu_items.  */
-  Lisp_Object help;
+  /* Help string or nil if none.  */
+  gc_handle help;
 
   /* True if enabled.  */
   bool enabled;

lwlib/lwlib.c

@@ -102,6 +102,7 @@ free_widget_value_tree (widget_value *wv)
   xfree (wv->name);
   xfree (wv->value);
   xfree (wv->key);
+  free_gc_handle (wv->help);
 
   wv->name = wv->value = wv->key = (char *) 0xDEADBEEF;
 
@@ -139,7 +140,7 @@ copy_widget_value_tree (widget_value *val, change_type change)
   copy->name = xstrdup (val->name);
   copy->value = val->value ? xstrdup (val->value) : NULL;
   copy->key = val->key ? xstrdup (val->key) : NULL;
-  copy->help = val->help;
+  copy->help = gc_handle_for_gc_handle (val->help);
   copy->enabled = val->enabled;
   copy->button_type = val->button_type;
   copy->selected = val->selected;
@@ -384,12 +385,13 @@ merge_widget_value (widget_value *val1,
       change = max (change, VISIBLE_CHANGE);
       dupstring (&val1->key, val2->key);
     }
-  if (! EQ (val1->help, val2->help))
+  if (!EQ (gc_handle_value (val1->help),
+	   gc_handle_value (val2->help)))
     {
       EXPLAIN (val1->name, change, VISIBLE_CHANGE, "help change",
 	       val1->help, val2->help);
       change = max (change, VISIBLE_CHANGE);
-      val1->help = val2->help;
+      gc_handle_assign (&val1->help, val2->help);
     }
   if (val1->enabled != val2->enabled)
     {

src/gc-handles.c

@@ -154,6 +154,19 @@ gc_handle_for_pvec (union vectorlike_header *h)
   return gc_handle_for (obj);
 }
 
+gc_handle
+gc_handle_for_gc_handle (gc_handle gch)
+{
+  return gc_handle_for (gc_handle_value (gch));
+}
+
+void
+gc_handle_assign (gc_handle *dst, gc_handle src)
+{
+  free_gc_handle (*dst);
+  *dst = gc_handle_for_gc_handle (src);
+}
+
 DEFUN ("gc-handles-info", Fgc_handles_info, Sgc_handles_info, 0, 0, 0,
        doc: /* Return information about registered GC handles.
 Return value is an list with the following entries:

src/gc-handles.h

@@ -27,9 +27,12 @@ typedef struct gc_handle_struct *gc_handle;
 
 gc_handle gc_handle_for (Lisp_Object);
 gc_handle gc_handle_for_pvec (union vectorlike_header *);
+gc_handle gc_handle_for_gc_handle (gc_handle src);
 void free_gc_handle (gc_handle);
 Lisp_Object gc_handle_value (gc_handle);
 
+void gc_handle_assign (gc_handle *dst, gc_handle src);
+
 void syms_of_gc_handles (void);
 
 #endif

src/gtkutil.c

@@ -3354,8 +3354,11 @@ make_menu_item (const char *utf8_label,
   if (! item->enabled) gtk_widget_set_sensitive (w, FALSE);
 
 #ifdef HAVE_PGTK
-  if (!NILP (item->help))
-    gtk_widget_set_tooltip_text (w, SSDATA (item->help));
+  {
+    Lisp_Object help = gc_handle_value (item->help);
+    if (!NILP (help))
+      gtk_widget_set_tooltip_text (w, SSDATA (help));
+  }
 #endif
 
   return w;
@@ -3401,7 +3404,7 @@ xg_create_one_menuitem (widget_value *item,
   xg_list_insert (&xg_menu_item_cb_list, &cb_data->ptrs);
 
   cb_data->select_id = 0;
-  cb_data->help = gc_handle_for (item->help);
+  cb_data->help = gc_handle_for_gc_handle (item->help);
   cb_data->cl_data = cl_data;
   cb_data->call_data = item->call_data;
 
@@ -3985,8 +3988,7 @@ xg_update_menu_item (widget_value *val,
   if (cb_data)
     {
       cb_data->call_data = val->call_data;
-      free_gc_handle (cb_data->help);
-      cb_data->help = gc_handle_for (val->help);
+      gc_handle_assign (&cb_data->help, val->help);
       cb_data->cl_data = cl_data;
 
       /* We assume the callback functions don't change.  */

src/menu.c

@@ -581,7 +581,7 @@ make_widget_value (const char *name, char *value,
   wv->name = (char *) name;
   wv->value = value;
   wv->enabled = enabled;
-  wv->help = help;
+  wv->help = gc_handle_for (help);
   return wv;
 }
 
@@ -596,6 +596,7 @@ free_menubar_widget_value_tree (widget_value *wv)
   if (! wv) return;
 
   wv->name = wv->value = wv->key = (char *) 0xDEADBEEF;
+  free_gc_handle (wv->help);
 
   if (wv->contents && (wv->contents != (widget_value *) 1))
     {

src/xmenu.c

@@ -772,7 +772,7 @@ static void
 menu_highlight_callback (Widget widget, LWLIB_ID id, void *call_data)
 {
   widget_value *wv = call_data;
-  Lisp_Object help = wv ? wv->help : Qnil;
+  Lisp_Object help = wv ? gc_handle_value (wv->help) : Qnil;
 
   /* Determine the frame for the help event.  */
   struct frame *f = menubar_id_to_frame (id);