Avoid NULL dereference.

* stack.c (return_command): Guard use of SYMBOL_TYPE (thisfun).
	New variable func_type.

gdb/ChangeLog

@@ -1,3 +1,10 @@
+2009-02-11  Jim Meyering  <meyering@redhat.com>
+	    Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	Avoid NULL dereference.
+	* stack.c (return_command): Guard use of SYMBOL_TYPE (thisfun).
+	New variable func_type.
+
 2009-02-11  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdbarch.c: Regenerate.

gdb/stack.c

@@ -1823,7 +1823,8 @@ return_command (char *retval_exp, int from_tty)
            is discarded, side effects such as "return i++" still
            occur.  */
 	return_value = NULL;
-      else if (using_struct_return (SYMBOL_TYPE (thisfun), return_type))
+      else if (thisfun != NULL
+	       && using_struct_return (SYMBOL_TYPE (thisfun), return_type))
 	{
 	  query_prefix = "\
 The location at which to store the function's return value is unknown.\n\
@@ -1856,10 +1857,12 @@ If you continue, the return value that you specified will be ignored.\n";
     {
       struct type *return_type = value_type (return_value);
       struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
-      gdb_assert (gdbarch_return_value (gdbarch, SYMBOL_TYPE (thisfun),
-      					return_type, NULL, NULL, NULL)
+      struct type *func_type = thisfun == NULL ? NULL : SYMBOL_TYPE (thisfun);
+
+      gdb_assert (gdbarch_return_value (gdbarch, func_type, return_type, NULL,
+					NULL, NULL)
 		  == RETURN_VALUE_REGISTER_CONVENTION);
-      gdbarch_return_value (gdbarch, SYMBOL_TYPE (thisfun), return_type,
+      gdbarch_return_value (gdbarch, func_type, return_type,
 			    get_current_regcache (), NULL /*read*/,
 			    value_contents (return_value) /*write*/);
     }