re PR testsuite/91065 (gcc.dg/plugin/start_unit_plugin.c uses ggc memory without…

re PR testsuite/91065 (gcc.dg/plugin/start_unit_plugin.c uses ggc memory without registering a root_tab)

        PR testsuite/91065
        * testsuite/gcc.dg/plugin/start_unit_plugin.c: Register a root tab
        to reference fake_var.

From-SVN: r272954

gcc/ChangeLog

+2019-07-02  Joern Rennecke  <joern.rennecke@riscy-ip.com>
+
+	PR testsuite/91065
+	* testsuite/gcc.dg/plugin/start_unit_plugin.c: Register a root tab
+	to reference fake_var.
+
 2019-07-02  qing zhao  <qing.zhao@oracle.com>
 
 	PR preprocessor/90581

gcc/testsuite/gcc.dg/plugin/start_unit_plugin.c

@@ -40,6 +40,19 @@ gate_start_unit (void)
 
 static void start_unit_callback (void *gcc_data, void *user_data)
 {
+  static const struct ggc_root_tab root[] = {
+    {
+      &fake_var,
+      1,
+      sizeof (fake_var),
+      &gt_ggc_mx_tree_node,
+      &gt_pch_nx_tree_node
+    },
+    LAST_GGC_ROOT_TAB
+  };
+
+  register_callback ("start_unit", PLUGIN_REGISTER_GGC_ROOTS, NULL,
+		     (void *)root);
   if (integer_type_node) {
     fake_var = build_decl (UNKNOWN_LOCATION, VAR_DECL, 
                            get_identifier ("_fake_var_"),