[Ada] Unnesting: ensure Current_Subprogram is always initialized

2018-12-11  Arnaud Charlet  <charlet@adacore.com>

gcc/ada/

	* exp_unst.adb (Unnest_Subprogram): Ensure Current_Subprogram is
	always initialized.

From-SVN: r267009

gcc/ada/ChangeLog

+2018-12-11  Arnaud Charlet  <charlet@adacore.com>
+
+	* exp_unst.adb (Unnest_Subprogram): Ensure Current_Subprogram is
+	always initialized.
+
 2018-12-11  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/decl.c (gnat_to_gnu_entity): Add

gcc/ada/exp_unst.adb

@@ -440,7 +440,7 @@ package body Exp_Unst is
       Urefs.Init;
 
       Build_Tables : declare
-         Current_Subprogram : Entity_Id;
+         Current_Subprogram : Entity_Id := Empty;
          --  When we scan a subprogram body, we set Current_Subprogram to the
          --  corresponding entity. This gets recursively saved and restored.