This patch extends the legality of the GNAT attribute Scalar_Storage_Order,
to apply to formal private types. Previously this extension applied only
in GNAT_Mode, to support instantiations of Ada.Sequential_IO, but it is more
generally useful.
The following must compile quietly:
----
with Memory_View_Generic;
procedure Main is
type T is array (1..10) of integer;
package OK is new Memory_View_Generic (T);
type T2 is new Long_Float;
package Wrong is new Memory_View_Generic (T2);
begin
null;
end;
----
with System;
generic
type Source_Type is private;
package Memory_View_Generic is
-- various declarations ...
SSO : System.Bit_Order := Source_Type'Scalar_Storage_Order;
end Memory_View_Generic;
Tested on x86_64-pc-linux-gnu, committed on trunk
2018-05-21 Ed Schonberg <schonb...@adacore.com>
gcc/ada/
* sem_attr.adb (Analyze_Attribute, case Scalar_Storage_Order): The
attribute reference is legal within a generic unit when the prefix is a
formal private type.--- gcc/ada/sem_attr.adb
+++ gcc/ada/sem_attr.adb
@@ -5709,11 +5709,15 @@ package body Sem_Attr is
if not (Is_Record_Type (P_Type) or else Is_Array_Type (P_Type)) then
- -- In GNAT mode, the attribute applies to generic types as well
- -- as composite types, and for non-composite types always returns
- -- the default bit order for the target.
-
- if not (GNAT_Mode and then Is_Generic_Type (P_Type))
+ -- The attribute applies to generic private types (in which case
+ -- the legality rule is applied in the instance) as well as to
+ -- composite types. For noncomposite types it always returns the
+ -- default bit order for the target.
+ -- Allowing formal private types was originally introduced in
+ -- GNAT_Mode only, to compile instances of Sequential_IO, but
+ -- users find it more generally useful in generic units.
+
+ if not (Is_Generic_Type (P_Type) and then Is_Private_Type (P_Type))
and then not In_Instance
then
Error_Attr_P
@@ -11074,7 +11078,7 @@ package body Sem_Attr is
-- The context may be a constrained access type (however ill-
-- advised such subtypes might be) so in order to generate a
- -- constraint check when needed set the type of the attribute
+ -- constraint check we need to set the type of the attribute
-- reference to the base type of the context.
Set_Etype (N, Btyp);
@@ -11837,6 +11841,8 @@ package body Sem_Attr is
if Attr_Id = Attribute_Elaborated then
null;
+ -- Should this be restricted to Expander_Active???
+
else
Freeze_Expression (P);
end if;
