The compiler generates wrong code on instantiations of package
Address_To_Access_Conversions when the generic formal is a class-wide
interface type; this causes wrong dispatching calls when the
access-to-class-wide-interface object returned by To_Pointer is used to
dispatch a call.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* exp_attr.adb (Expand_N_Attribute_Reference): The expansion of
'Address in a call to an instantiation of the implicit
subprogram To_Pointer with a class-wide interface type target
requires adding an implicit type conversion to force
displacement of the "this" pointer.diff --git a/gcc/ada/exp_attr.adb b/gcc/ada/exp_attr.adb
--- a/gcc/ada/exp_attr.adb
+++ b/gcc/ada/exp_attr.adb
@@ -2543,6 +2543,28 @@ package body Exp_Attr is
Analyze_And_Resolve (N, Addr);
end;
+ -- 'Address is an actual parameter of the call to the implicit
+ -- subprogram To_Pointer instantiated with a class-wide interface
+ -- type; its expansion requires adding an implicit type conversion
+ -- to force displacement of the "this" pointer.
+
+ elsif Tagged_Type_Expansion
+ and then Nkind (Parent (N)) = N_Function_Call
+ and then Nkind (Name (Parent (N))) in N_Has_Entity
+ and then Is_Intrinsic_Subprogram (Entity (Name (Parent (N))))
+ and then Chars (Entity (Name (Parent (N)))) = Name_To_Pointer
+ and then Is_Interface (Designated_Type (Etype (Parent (N))))
+ and then Is_Class_Wide_Type (Designated_Type (Etype (Parent (N))))
+ then
+ declare
+ Iface_Typ : constant Entity_Id :=
+ Designated_Type (Etype (Parent (N)));
+ begin
+ Rewrite (Pref, Convert_To (Iface_Typ, Relocate_Node (Pref)));
+ Analyze_And_Resolve (Pref, Iface_Typ);
+ return;
+ end;
+
-- Ada 2005 (AI-251): Class-wide interface objects are always
-- "displaced" to reference the tag associated with the interface
-- type. In order to obtain the real address of such objects we
@@ -2554,9 +2576,9 @@ package body Exp_Attr is
-- of nested subprograms), since the address needs to be assigned
-- as-is to such components.
- elsif Is_Class_Wide_Type (Ptyp)
+ elsif Tagged_Type_Expansion
+ and then Is_Class_Wide_Type (Ptyp)
and then Is_Interface (Underlying_Type (Ptyp))
- and then Tagged_Type_Expansion
and then not (Nkind (Pref) in N_Has_Entity
and then Is_Subprogram (Entity (Pref)))
and then not Is_Unnested_Component_Init (N)
@@ -2564,8 +2586,7 @@ package body Exp_Attr is
Rewrite (N,
Make_Function_Call (Loc,
Name => New_Occurrence_Of (RTE (RE_Base_Address), Loc),
- Parameter_Associations => New_List (
- Relocate_Node (N))));
+ Parameter_Associations => New_List (Relocate_Node (N))));
Analyze (N);
return;
end if;
