exp_alfa.adb: Add local constant Disable_Processing_Of_Renamings;

2011-11-04  Hristian Kirtchev  <kirtchev@adacore.com>

	* exp_alfa.adb: Add local constant
	Disable_Processing_Of_Renamings;
	(Expand_Alfa_N_Object_Renaming_Declaration): Disable
	the name evaluation of object renamings for now.
	(Expand_Potential_Renaming): Do not perform the substitution
	for now.
	* exp_util.adb (Remove_Side_Effects): Remove processing for
        functions with side effects in Alfa mode.

From-SVN: r180953

gcc/ada/ChangeLog

+2011-11-04  Hristian Kirtchev  <kirtchev@adacore.com>
+
+	* exp_alfa.adb: Add local constant
+	Disable_Processing_Of_Renamings;
+	(Expand_Alfa_N_Object_Renaming_Declaration): Disable
+	the name evaluation of object renamings for now.
+	(Expand_Potential_Renaming): Do not perform the substitution
+	for now.
+	* exp_util.adb (Remove_Side_Effects): Remove processing for
+        functions with side effects in Alfa mode.
+
 2011-11-04  Gary Dismukes  <dismukes@adacore.com>
 
 	* bindgen.adb (Gen_Elab_Calls): In the case

gcc/ada/exp_alfa.adb

@@ -42,6 +42,8 @@ with Tbuild;   use Tbuild;
 
 package body Exp_Alfa is
 
+   Disable_Processing_Of_Renamings : constant Boolean := True;
+
    -----------------------
    -- Local Subprograms --
    -----------------------
@@ -209,6 +211,10 @@ package body Exp_Alfa is
 
    procedure Expand_Alfa_N_Object_Renaming_Declaration (N : Node_Id) is
    begin
+      if Disable_Processing_Of_Renamings then
+         return;
+      end if;
+
       --  Unconditionally remove all side effects from the name
 
       Evaluate_Name (Name (N));
@@ -297,6 +303,10 @@ package body Exp_Alfa is
       T : constant Entity_Id := Etype (N);
 
    begin
+      if Disable_Processing_Of_Renamings then
+         return;
+      end if;
+
       --  Substitute a reference to a renaming with the actual renamed object
 
       if Present (Renamed_Object (E)) then

gcc/ada/exp_util.adb

@@ -168,23 +168,30 @@ package body Exp_Util is
       Msg_Node : Node_Id;
 
    begin
-
       case Nkind (Parent (N)) is
-         when N_Attribute_Reference |
 
+         --  Check for cases of appearing in the prefix of a construct where
+         --  we don't need atomic synchronization for this kind of usage.
+
+         when
               --  Nothing to do if we are the prefix of an attribute, since we
               --  do not want an atomic sync operation for things like 'Size.
 
+              N_Attribute_Reference |
+
+              --  The N_Reference node is like an attribute
+
               N_Reference           |
 
-            --  Likewise for a mere reference
+              --  Nothing to do for a reference to a component (or components)
+              --  of a composite object. Only reads and updates of the object
+              --  as a whole require atomic synchronization (RM C.6 (15)).
 
               N_Indexed_Component   |
               N_Selected_Component  |
               N_Slice               =>
 
-            --  The C.6(15) clause says that only reads and updates of the
-            --  object as a whole require atomic synchronization.
+            --  For all the above cases, nothing to do if we are the prefix
 
             if Prefix (Parent (N)) = N then
                return;
@@ -6547,29 +6554,6 @@ package body Exp_Util is
             end;
          end if;
 
-         Def_Id := Make_Temporary (Loc, 'R', Exp);
-         Set_Etype (Def_Id, Exp_Type);
-
-         --  The regular expansion of functions with side effects involves the
-         --  generation of an access type to capture the return value found on
-         --  the secondary stack. Since Alfa (and why) cannot process access
-         --  types, use a different approach which ignores the secondary stack
-         --  and "copies" the returned object.
-
-         if Alfa_Mode then
-            Res := New_Reference_To (Def_Id, Loc);
-            Ref_Type := Exp_Type;
-
-         --  Regular expansion utilizing an access type and 'reference
-
-         else
-            Res :=
-              Make_Explicit_Dereference (Loc,
-                Prefix => New_Reference_To (Def_Id, Loc));
-
-            --  Generate:
-            --    type Ann is access all <Exp_Type>;
-
          Ref_Type := Make_Temporary (Loc, 'A');
 
          Ptr_Typ_Decl :=
@@ -6581,24 +6565,22 @@ package body Exp_Util is
                  Subtype_Indication =>
                    New_Reference_To (Exp_Type, Loc)));
 
+         E := Exp;
          Insert_Action (Exp, Ptr_Typ_Decl);
-         end if;
 
-         E := Exp;
+         Def_Id := Make_Temporary (Loc, 'R', Exp);
+         Set_Etype (Def_Id, Exp_Type);
+
+         Res :=
+           Make_Explicit_Dereference (Loc,
+             Prefix => New_Reference_To (Def_Id, Loc));
+
          if Nkind (E) = N_Explicit_Dereference then
             New_Exp := Relocate_Node (Prefix (E));
          else
             E := Relocate_Node (E);
-
-            --  Do not generate a 'reference in Alfa since the access type is
-            --  not generated.
-
-            if Alfa_Mode then
-               New_Exp := E;
-            else
             New_Exp := Make_Reference (Loc, E);
          end if;
-         end if;
 
          if Is_Delayed_Aggregate (E) then