From: Piotr Trojanek <troja...@adacore.com>
Implement missing behavior of RM 13.9 (25.1/3): Tag_Error is raised by a
call of Interface_Ancestor_Tags and Is_Descendant_At_Same_Level, if any
tag passed is No_Tag. This change also fixes Descendant_Tag, which
relies on Is_Descendant_At_Same_Level. The remaining operations already
worked properly.
gcc/ada/
* libgnat/a-tags.adb
(Interface_Ancestor_Tags): Raise Tag_Error on No_Tag.
(Is_Descendant_At_Same_Level): Likewise.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/libgnat/a-tags.adb | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/gcc/ada/libgnat/a-tags.adb b/gcc/ada/libgnat/a-tags.adb
index d663a41f5a8..a9af942fc64 100644
--- a/gcc/ada/libgnat/a-tags.adb
+++ b/gcc/ada/libgnat/a-tags.adb
@@ -554,13 +554,18 @@ package body Ada.Tags is
-----------------------------
function Interface_Ancestor_Tags (T : Tag) return Tag_Array is
- TSD_Ptr : constant Addr_Ptr :=
- To_Addr_Ptr (To_Address (T) - DT_Typeinfo_Ptr_Size);
- TSD : constant Type_Specific_Data_Ptr :=
- To_Type_Specific_Data_Ptr (TSD_Ptr.all);
- Iface_Table : constant Interface_Data_Ptr := TSD.Interfaces_Table;
-
+ TSD_Ptr : Addr_Ptr;
+ TSD : Type_Specific_Data_Ptr;
+ Iface_Table : Interface_Data_Ptr;
begin
+ if T = No_Tag then
+ raise Tag_Error;
+ end if;
+
+ TSD_Ptr := To_Addr_Ptr (To_Address (T) - DT_Typeinfo_Ptr_Size);
+ TSD := To_Type_Specific_Data_Ptr (TSD_Ptr.all);
+ Iface_Table := TSD.Interfaces_Table;
+
if Iface_Table = null then
declare
Table : Tag_Array (1 .. 0);
@@ -731,7 +736,10 @@ package body Ada.Tags is
Ancestor : Tag) return Boolean
is
begin
- if Descendant = Ancestor then
+ if Descendant = No_Tag or else Ancestor = No_Tag then
+ raise Tag_Error;
+
+ elsif Descendant = Ancestor then
return True;
else
--
2.34.1
