re PR fortran/40270 (Revision 147883 caused many Fortran regressions)

2009-05-27  Tobias Burnus  <burnus@net-b.de>

        PR fortran/40270
        * trans-decl.c (create_main_function): Mark MAIN__ and
        argc/argv as TREE_USED and push/pop function_decl context
        if needed.

From-SVN: r147926

gcc/fortran/ChangeLog

+2009-05-27  Tobias Burnus  <burnus@net-b.de>
+
+	PR fortran/40270
+	* trans-decl.c (create_main_function): Mark MAIN__ and
+	argc/argv as TREE_USED and push/pop function_decl context
+	if needed.
+
 2009-05-26  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/39178

gcc/fortran/trans-decl.c

@@ -3838,11 +3838,20 @@ add_argument_checking (stmtblock_t *block, gfc_symbol *sym)
 static void
 create_main_function (tree fndecl)
 {
-
+  tree old_context;
   tree ftn_main;
   tree tmp, decl, result_decl, argc, argv, typelist, arglist;
   stmtblock_t body;
 
+  old_context = current_function_decl;
+
+  if (old_context)
+    {
+      push_function_context ();
+      saved_parent_function_decls = saved_function_decls;
+      saved_function_decls = NULL_TREE;
+    }
+
   /* main() function must be declared with global scope.  */
   gcc_assert (current_function_decl == NULL_TREE);
 
@@ -3903,6 +3912,8 @@ create_main_function (tree fndecl)
   /* Call some libgfortran initialization routines, call then MAIN__(). */
 
   /* Call _gfortran_set_args (argc, argv).  */
+  TREE_USED (argc) = 1;
+  TREE_USED (argv) = 1;
   tmp = build_call_expr (gfor_fndecl_set_args, 2, argc, argv);
   gfc_add_expr_to_block (&body, tmp);
 
@@ -4000,6 +4011,9 @@ create_main_function (tree fndecl)
   tmp = build_call_expr (fndecl, 0);
   gfc_add_expr_to_block (&body, tmp);
 
+  /* Mark MAIN__ as used.  */
+  TREE_USED (fndecl) = 1;
+
   /* "return 0".  */
   tmp = fold_build2 (MODIFY_EXPR, integer_type_node, DECL_RESULT (ftn_main),
 		     build_int_cst (integer_type_node, 0));
@@ -4023,6 +4037,13 @@ create_main_function (tree fndecl)
 
   gfc_gimplify_function (ftn_main);
   cgraph_finalize_function (ftn_main, false);
+
+  if (old_context)
+    {
+      pop_function_context ();
+      saved_function_decls = saved_parent_function_decls;
+    }
+  current_function_decl = old_context;
 }