translate: for alias of signal slice: trsnslate name subtype.

Fix #649

3 files changed, 43 insertions, 0 deletions

diff --git a/src/vhdl/translate/trans-chap3.adb b/src/vhdl/translate/trans-chap3.adb
index fb7a53aeb..ced7e1a94 100644
--- a/src/vhdl/translate/trans-chap3.adb
+++ b/src/vhdl/translate/trans-chap3.adb
@@ -3203,6 +3203,18 @@ package body Trans.Chap3 is
                     Tinfo.B.Bounds_Ptr_Type));
    end Allocate_Unbounded_Composite_Bounds;
 
+   procedure Translate_Array_Subtype (Arr_Type : Iir) is
+   begin
+      Chap3.Translate_Subtype_Definition
+        (Arr_Type, Get_Base_Type (Arr_Type), False);
+      Chap3.Create_Composite_Subtype_Bounds_Var (Arr_Type, False);
+   end Translate_Array_Subtype;
+
+   procedure Elab_Array_Subtype (Arr_Type : Iir) is
+   begin
+      Chap3.Elab_Composite_Subtype_Bounds (Arr_Type);
+   end Elab_Array_Subtype;
+
    procedure Create_Array_Subtype (Sub_Type : Iir)
    is
       Mark : Id_Mark_Type;
diff --git a/src/vhdl/translate/trans-chap3.ads b/src/vhdl/translate/trans-chap3.ads
index daed65d93..9900f48a9 100644
--- a/src/vhdl/translate/trans-chap3.ads
+++ b/src/vhdl/translate/trans-chap3.ads
@@ -265,6 +265,11 @@ package Trans.Chap3 is
       Res        : Mnode;
       Obj_Type   : Iir);
 
+   --  Used for alias: create the vars for the subtype of the name (when the
+   --  name is a slice).  The identifier prefix must have been set.
+   procedure Translate_Array_Subtype (Arr_Type : Iir);
+   procedure Elab_Array_Subtype (Arr_Type : Iir);
+
    --  Create the bounds for SUB_TYPE.
    --  SUB_TYPE is expected to be a non-static, anonymous array type.
    procedure Create_Array_Subtype (Sub_Type : Iir);
diff --git a/src/vhdl/translate/trans-chap4.adb b/src/vhdl/translate/trans-chap4.adb
index b2011df12..47b9f5674 100644
--- a/src/vhdl/translate/trans-chap4.adb
+++ b/src/vhdl/translate/trans-chap4.adb
@@ -1537,6 +1537,7 @@ package body Trans.Chap4 is
      (Decl : Iir_Object_Alias_Declaration)
    is
       Decl_Type : constant Iir := Get_Type (Decl);
+      Name      : constant Iir := Get_Name (Decl);
       Info      : Alias_Info_Acc;
       Tinfo     : Type_Info_Acc;
       Atype     : O_Tnode;
@@ -1583,6 +1584,24 @@ package body Trans.Chap4 is
          end if;
          Info.Alias_Var (Mode) := Create_Var (Id, Atype);
       end loop;
+
+      if Get_Kind (Name) = Iir_Kind_Slice_Name
+        and then Info.Alias_Kind = Mode_Signal
+      then
+         --  The name subtype will be evaluated once at elaboration, as it is
+         --  needed when direct drivers are used (in that case, the name is
+         --  evaluated once again).
+         declare
+            Name_Type : constant Iir := Get_Type (Name);
+            Mark1, Mark2 : Id_Mark_Type;
+         begin
+            Push_Identifier_Prefix (Mark1, Get_Identifier (Decl));
+            Push_Identifier_Prefix (Mark2, "AT");
+            Chap3.Translate_Array_Subtype (Name_Type);
+            Pop_Identifier_Prefix (Mark2);
+            Pop_Identifier_Prefix (Mark1);
+         end;
+      end if;
    end Translate_Object_Alias_Declaration;
 
    procedure Elab_Object_Alias_Declaration
@@ -1601,6 +1620,13 @@ package body Trans.Chap4 is
 
       Open_Temp;
 
+      if Get_Kind (Name) = Iir_Kind_Slice_Name
+        and then Alias_Info.Alias_Kind = Mode_Signal
+      then
+         --  See Translate_Object_Alias_Declaration.
+         Chap3.Elab_Array_Subtype (Name_Type);
+      end if;
+
       case Alias_Info.Alias_Kind is
          when Mode_Value =>
             Name_Node (Mode_Value) := Chap6.Translate_Name (Name, Mode_Value);