exp_strm.adb (Build_Record_Or_Elementary_Input_Function): If this is an Input…

exp_strm.adb (Build_Record_Or_Elementary_Input_Function): If this is an Input function for an access type...

2008-04-08  Ed Schonberg  <schonberg@adacore.com>

	* exp_strm.adb (Build_Record_Or_Elementary_Input_Function): If this is
	an Input function for an access type, do not perform default
	initialization on the local variable that receives the value, to
	prevent spurious warnings when the type is null-excluding.

From-SVN: r134032

gcc/ada/exp_strm.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
+--          Copyright (C) 1992-2008, Free Software Foundation, Inc.         --
 --                                                                          --
 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -373,7 +373,7 @@ package body Exp_Strm is
       --  array may be user-defined, and be frozen after the type for which
       --  we are generating the stream subprogram. In that case, freeze the
       --  stream attribute of the component type, whose declaration could not
-      --  generate any additional freezing actions in any case. See 5509-003.
+      --  generate any additional freezing actions in any case.
 
       if Nam = Name_Read then
          RW := TSS (Base_Type (Ctyp), TSS_Stream_Read);
@@ -1092,13 +1092,14 @@ package body Exp_Strm is
       Decl : out Node_Id;
       Fnam : out Entity_Id)
    is
-      Cn     : Name_Id;
-      J      : Pos;
-      Decls  : List_Id;
-      Constr : List_Id;
-      Stms   : List_Id;
-      Discr  : Entity_Id;
-      Odef   : Node_Id;
+      Cn       : Name_Id;
+      J        : Pos;
+      Decls    : List_Id;
+      Constr   : List_Id;
+      Obj_Decl : Node_Id;
+      Stms     : List_Id;
+      Discr    : Entity_Id;
+      Odef     : Node_Id;
 
    begin
       Decls  := New_List;
@@ -1152,14 +1153,23 @@ package body Exp_Strm is
 
       --  Perhaps we should just generate an extended return in all cases???
 
+      Obj_Decl :=
+        Make_Object_Declaration (Loc,
+          Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
+          Object_Definition => Odef);
+
+      --  If the type is an access type, do not perform default initialization.
+      --  The object is about to get its value from Read, and if the type is
+      --  null excluding we do not want spurious warnings on an initial null.
+
+      if Is_Access_Type (Typ) then
+         Set_No_Initialization (Obj_Decl);
+      end if;
+
       if Ada_Version >= Ada_05 then
          Stms := New_List (
            Make_Extended_Return_Statement (Loc,
-             Return_Object_Declarations =>
-               New_List (Make_Object_Declaration (Loc,
-                           Defining_Identifier =>
-                             Make_Defining_Identifier (Loc, Name_V),
-                           Object_Definition => Odef)),
+             Return_Object_Declarations => New_List (Obj_Decl),
              Handled_Statement_Sequence =>
                Make_Handled_Sequence_Of_Statements (Loc,
                  New_List (Make_Attribute_Reference (Loc,
@@ -1170,10 +1180,7 @@ package body Exp_Strm is
                                Make_Identifier (Loc, Name_V)))))));
 
       else
-         Append_To (Decls,
-           Make_Object_Declaration (Loc,
-             Defining_Identifier => Make_Defining_Identifier (Loc, Name_V),
-             Object_Definition => Odef));
+         Append_To (Decls, Obj_Decl);
 
          Stms := New_List (
             Make_Attribute_Reference (Loc,