configuration: add Check_Entity_Declaration_Top from translation.

evaluation: add Get_Path_Instance_Name_Suffix from translation.
grt-signals: rename ghdl_signal_direct_driver to ghdl_signal_add_direct_driver.
 add ghdl_signal_direct_assign; make active_chain private.

10 files changed, 444 insertions, 348 deletions

diff --git a/configuration.adb b/configuration.adb
index 7fdcfb0b0..43dbafd7b 100644
--- a/configuration.adb
+++ b/configuration.adb
@@ -21,6 +21,7 @@ with Std_Package;
 with Sem_Names;
 with Name_Table; use Name_Table;
 with Flags;
+with Iirs_Utils;
 
 package body Configuration is
    procedure Add_Design_Concurrent_Stmts (Parent : Iir);
@@ -572,4 +573,41 @@ package body Configuration is
       return Top;
    end Configure;
 
+   procedure Check_Entity_Declaration_Top (Entity : Iir_Entity_Declaration)
+   is
+      Has_Error : Boolean := False;
+
+      procedure Error (Msg : String; Loc : Iir) is
+      begin
+         if not Has_Error then
+            Error_Msg_Elab
+              (Disp_Node (Entity) & " cannot be at the top of a design");
+            Has_Error := True;
+         end if;
+         Error_Msg_Elab (Msg, Loc);
+      end Error;
+
+      El : Iir;
+   begin
+      --  Check generics.
+      El := Get_Generic_Chain (Entity);
+      while El /= Null_Iir loop
+         if Get_Default_Value (El) = Null_Iir then
+            Error ("(" & Disp_Node (El) & " has no default value)", El);
+         end if;
+         El := Get_Chain (El);
+      end loop;
+
+      --  Check port.
+      El := Get_Port_Chain (Entity);
+      while El /= Null_Iir loop
+         if not Iirs_Utils.Is_Fully_Constrained_Type (Get_Type (El))
+           and then Get_Default_Value (El) = Null_Iir
+         then
+            Error ("(" & Disp_Node (El)
+                     & " is unconstrained and has no default value)", El);
+         end if;
+         El := Get_Chain (El);
+      end loop;
+   end Check_Entity_Declaration_Top;
 end Configuration;
diff --git a/configuration.ads b/configuration.ads
index 9b5ea9b3e..0a19a23c2 100644
--- a/configuration.ads
+++ b/configuration.ads
@@ -46,4 +46,10 @@ package Configuration is
    Flag_Load_All_Design_Units : Boolean := True;
 
    Flag_Build_File_Dependence : Boolean := False;
+
+   --  Check if ENTITY can be at the top of a hierarchy, ie:
+   --  ENTITY has no generics or all generics have a default expression
+   --  ENTITY has no ports or all ports type are constrained.
+   --  If not, emit a elab error message.
+   procedure Check_Entity_Declaration_Top (Entity : Iir_Entity_Declaration);
 end Configuration;
diff --git a/evaluation.adb b/evaluation.adb
index 084050039..f193d1c66 100644
--- a/evaluation.adb
+++ b/evaluation.adb
@@ -15,6 +15,7 @@
 --  along with GHDL; see the file COPYING.  If not, write to the Free
 --  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 --  02111-1307, USA.
+with Ada.Unchecked_Deallocation;
 with Errorout; use Errorout;
 with Name_Table; use Name_Table;
 with Str_Table;
@@ -1470,51 +1471,56 @@ package body Evaluation is
          return C = ' ' or C = NBSP or C = HT;
       end White;
 
-      UnitName : String(Val'range);
+      UnitName : String (Val'range);
+      Mult : Iir_Int64;
       Sep : Natural;
       Found_Unit : Boolean := false;
       Found_Real : Boolean := false;
       Unit : Iir := Get_Primary_Unit (Phys_Type);
    begin
       -- Separate string into numeric value and make lowercase unit.
-      for i in reverse Val'range loop
-         UnitName(i) := Ada.Characters.Handling.To_Lower (Val(i));
-         if White(Val(i)) and Found_Unit then
-            Sep := i;
+      for I in reverse Val'range loop
+         UnitName (I) := Ada.Characters.Handling.To_Lower (Val (I));
+         if White (Val (I)) and Found_Unit then
+            Sep := I;
             exit;
          else
             Found_Unit := true;
          end if;
       end loop;
+
       -- Unit name  is UnitName(Sep+1..Unit'Last)
-      for i in Val'first .. Sep loop
-         if Val(i) = '.' then
+      for I in Val'First .. Sep loop
+         if Val (I) = '.' then
             Found_Real := true;
          end if;
       end loop;
+
       -- Chain down the units looking for matching one
       Unit := Get_Primary_Unit (Phys_Type);
       while Unit /= Null_Iir loop
-         exit when UnitName(Sep+1..UnitName'Last) = Image_Identifier(Unit);
+         exit when (UnitName (Sep + 1 .. UnitName'Last)
+                      = Image_Identifier (Unit));
          Unit := Get_Chain (Unit);
       end loop;
       if Unit = Null_Iir then
-         Error_Msg_Sem ("Unit """ & UnitName(Sep+1..UnitName'Last)
+         Error_Msg_Sem ("Unit """ & UnitName (Sep + 1 .. UnitName'Last)
                          & """ not in physical type", Expr);
          return Null_Iir;
       end if;
+
+      Mult := Get_Value (Get_Physical_Unit_Value (Unit));
       if Found_Real then
-         return Build_Physical(Iir_Int64(
-                                    Iir_Fp64'value(Val(Val'first .. Sep)) *
-                                    Iir_Fp64(Get_Value (Get_Physical_Unit_Value
-                                    (Unit)))), Expr);
+         return Build_Physical
+           (Iir_Int64 (Iir_Fp64'Value (Val (Val'First .. Sep))
+                         * Iir_Fp64 (Mult)),
+            Expr);
       else
-         return Build_Physical(Iir_Int64'value(Val(Val'first .. Sep)) *
-                             Get_Value (Get_Physical_Unit_Value(Unit)), Expr);
+         return Build_Physical
+           (Iir_Int64'Value (Val (Val'First .. Sep)) * Mult, Expr);
       end if;
    end Build_Physical_Value;
 
-
    function Eval_Incdec (Expr : Iir; N : Iir_Int64) return Iir
    is
       P : Iir_Int64;
@@ -1814,11 +1820,11 @@ package body Evaluation is
                   -- what type are we converting the string to?
                   Param_Type := Get_Base_Type (Get_Type (Expr));
                   declare
-                     Value : constant String := Image_String_Lit(Param);
+                     Value : constant String := Image_String_Lit (Param);
                   begin
                      case Get_Kind (Param_Type) is
                      when Iir_Kind_Integer_Type_Definition =>
-                        return Build_Discrete(Iir_Int64'value(Value), Expr);
+                        return Build_Discrete (Iir_Int64'Value (Value), Expr);
                      when Iir_Kind_Enumeration_Type_Definition =>
                         return Build_Enumeration_Value (Value, Param_Type,
                                                         Expr);
@@ -2566,4 +2572,221 @@ package body Evaluation is
       return Compare_Eq;
    end Compare_String_Literals;
 
+   function Get_Path_Instance_Name_Suffix (Attr : Iir)
+                                          return Path_Instance_Name_Type
+   is
+      --  Current path for name attributes.
+      Path_Str : String_Acc := null;
+      Path_Maxlen : Natural := 0;
+      Path_Len : Natural;
+      Path_Instance : Iir;
+
+      procedure Deallocate is new Ada.Unchecked_Deallocation
+        (Name => String_Acc, Object => String);
+
+      procedure Path_Reset is
+      begin
+         Path_Len := 0;
+         Path_Instance := Null_Iir;
+         if Path_Maxlen = 0 then
+            Path_Maxlen := 256;
+            Path_Str := new String (1 .. Path_Maxlen);
+         end if;
+      end Path_Reset;
+
+      procedure Path_Add (Str : String)
+      is
+         N_Len : Natural;
+         N_Path : String_Acc;
+      begin
+         N_Len := Path_Maxlen;
+         loop
+            exit when Path_Len + Str'Length <= N_Len;
+            N_Len := N_Len * 2;
+         end loop;
+         if N_Len /= Path_Maxlen then
+            N_Path := new String (1 .. N_Len);
+            N_Path (1 .. Path_Len) := Path_Str (1 .. Path_Len);
+            Deallocate (Path_Str);
+            Path_Str := N_Path;
+            Path_Maxlen := N_Len;
+         end if;
+         Path_Str (Path_Len + 1 .. Path_Len + Str'Length) := Str;
+         Path_Len := Path_Len + Str'Length;
+      end Path_Add;
+
+      procedure Path_Add_Type_Name (Atype : Iir)
+      is
+         Adecl : Iir;
+      begin
+         Adecl := Get_Type_Declarator (Atype);
+         Image (Get_Identifier (Adecl));
+         Path_Add (Name_Buffer (1 .. Name_Length));
+      end Path_Add_Type_Name;
+
+      procedure Path_Add_Signature (Subprg : Iir)
+      is
+         Chain : Iir;
+      begin
+         Path_Add ("[");
+         Chain := Get_Interface_Declaration_Chain (Subprg);
+         while Chain /= Null_Iir loop
+            Path_Add_Type_Name (Get_Type (Chain));
+            Chain := Get_Chain (Chain);
+            if Chain /= Null_Iir then
+               Path_Add (",");
+            end if;
+         end loop;
+
+         case Get_Kind (Subprg) is
+            when Iir_Kind_Function_Declaration
+              | Iir_Kind_Implicit_Function_Declaration =>
+               Path_Add (" return ");
+               Path_Add_Type_Name (Get_Return_Type (Subprg));
+            when others =>
+               null;
+         end case;
+         Path_Add ("]");
+      end Path_Add_Signature;
+
+      procedure Path_Add_Name (N : Iir) is
+      begin
+         Eval_Simple_Name (Get_Identifier (N));
+         if Name_Buffer (1) /= 'P' then
+            --  Skip anonymous processes.
+            Path_Add (Name_Buffer (1 .. Name_Length));
+         end if;
+      end Path_Add_Name;
+
+      procedure Path_Add_Element (El : Iir; Is_Instance : Boolean) is
+      begin
+         --  LRM 14.1
+         --  E'INSTANCE_NAME
+         --    There is one full path instance element for each component
+         --    instantiation, block statement, generate statemenent, process
+         --    statement, or subprogram body in the design hierarchy between
+         --    the top design entity and the named entity denoted by the
+         --    prefix.
+         --
+         --  E'PATH_NAME
+         --    There is one path instance element for each component
+         --    instantiation, block statement, generate statement, process
+         --    statement, or subprogram body in the design hierarchy between
+         --    the root design entity and the named entity denoted by the
+         --    prefix.
+         case Get_Kind (El) is
+            when Iir_Kind_Library_Declaration =>
+               Path_Add (":");
+               Path_Add_Name (El);
+               Path_Add (":");
+            when Iir_Kind_Package_Declaration
+              | Iir_Kind_Package_Body =>
+               Path_Add_Element
+                 (Get_Library (Get_Design_File (Get_Design_Unit (El))),
+                  Is_Instance);
+               Path_Add_Name (El);
+               Path_Add (":");
+            when Iir_Kind_Entity_Declaration =>
+               Path_Instance := El;
+            when Iir_Kind_Architecture_Declaration =>
+               Path_Instance := El;
+            when Iir_Kind_Design_Unit =>
+               Path_Add_Element (Get_Library_Unit (El), Is_Instance);
+            when Iir_Kind_Sensitized_Process_Statement
+              | Iir_Kind_Process_Statement
+              | Iir_Kind_Block_Statement =>
+               Path_Add_Element (Get_Parent (El), Is_Instance);
+               Path_Add_Name (El);
+               Path_Add (":");
+            when Iir_Kind_Function_Declaration
+              | Iir_Kind_Procedure_Declaration
+              | Iir_Kind_Implicit_Function_Declaration
+              | Iir_Kind_Implicit_Procedure_Declaration =>
+               Path_Add_Element (Get_Parent (El), Is_Instance);
+               Path_Add_Name (El);
+               if Flags.Vhdl_Std >= Vhdl_02 then
+                  --  Add signature.
+                  Path_Add_Signature (El);
+               end if;
+               Path_Add (":");
+            when Iir_Kind_Procedure_Body =>
+               Path_Add_Element (Get_Subprogram_Specification (El),
+                                 Is_Instance);
+            when Iir_Kind_Generate_Statement =>
+               declare
+                  Scheme : Iir;
+               begin
+                  Scheme := Get_Generation_Scheme (El);
+                  if Get_Kind (Scheme) = Iir_Kind_Iterator_Declaration then
+                     Path_Instance := El;
+                  else
+                     Path_Add_Element (Get_Parent (El), Is_Instance);
+                     Path_Add_Name (El);
+                     Path_Add (":");
+                  end if;
+               end;
+            when Iir_Kinds_Sequential_Statement =>
+               Path_Add_Element (Get_Parent (El), Is_Instance);
+            when others =>
+               Error_Kind ("path_add_element", El);
+         end case;
+      end Path_Add_Element;
+
+      Prefix : constant Iir := Get_Prefix (Attr);
+      Is_Instance : constant Boolean :=
+        Get_Kind (Attr) = Iir_Kind_Instance_Name_Attribute;
+   begin
+      Path_Reset;
+
+      --  LRM 14.1
+      --  E'PATH_NAME
+      --    The local item name in E'PATH_NAME equals E'SIMPLE_NAME, unless
+      --    E denotes a library, package, subprogram or label. In this
+      --    latter case, the package based path or instance based path,
+      --    as appropriate, will not contain a local item name.
+      --
+      --  E'INSTANCE_NAME
+      --    The local item name in E'INSTANCE_NAME equals E'SIMPLE_NAME,
+      --    unless E denotes a library, package, subprogram, or label.  In
+      --    this latter case, the package based path or full instance based
+      --    path, as appropriate, will not contain a local item name.
+      case Get_Kind (Prefix) is
+         when Iir_Kind_Constant_Declaration
+           | Iir_Kind_Constant_Interface_Declaration
+           | Iir_Kind_Iterator_Declaration
+           | Iir_Kind_Variable_Declaration
+           | Iir_Kind_Variable_Interface_Declaration
+           | Iir_Kind_Signal_Declaration
+           | Iir_Kind_Signal_Interface_Declaration
+           | Iir_Kind_File_Declaration
+           | Iir_Kind_File_Interface_Declaration
+           | Iir_Kind_Type_Declaration
+           | Iir_Kind_Subtype_Declaration =>
+            Path_Add_Element (Get_Parent (Prefix), Is_Instance);
+            Path_Add_Name (Prefix);
+         when Iir_Kind_Library_Declaration
+           | Iir_Kind_Design_Unit
+           | Iir_Kind_Package_Declaration
+           | Iir_Kind_Function_Declaration
+           | Iir_Kind_Procedure_Declaration
+           | Iir_Kind_Implicit_Function_Declaration
+           | Iir_Kind_Implicit_Procedure_Declaration
+           | Iir_Kinds_Concurrent_Statement
+           | Iir_Kinds_Sequential_Statement =>
+            Path_Add_Element (Prefix, Is_Instance);
+         when others =>
+            Error_Kind ("get_path_instance_name_suffix", Prefix);
+      end case;
+
+      declare
+         Result : constant Path_Instance_Name_Type :=
+           (Len => Path_Len,
+            Path_Instance => Path_Instance,
+            Suffix => Path_Str (1 .. Path_Len));
+      begin
+         Deallocate (Path_Str);
+         return Result;
+      end;
+   end Get_Path_Instance_Name_Suffix;
+
 end Evaluation;
diff --git a/evaluation.ads b/evaluation.ads
index 7a4df00bb..86dd977b4 100644
--- a/evaluation.ads
+++ b/evaluation.ads
@@ -104,4 +104,16 @@ package Evaluation is
    --  Compare two string literals (of same length).
    type Compare_Type is (Compare_Lt, Compare_Eq, Compare_Gt);
    function Compare_String_Literals (L, R : Iir) return Compare_Type;
+
+   --  Return the local part of 'Instance_Name or 'Path_Name.
+   type Path_Instance_Name_Type (Len : Natural) is record
+      --  The node before suffix (entity, architecture or generate iterator).
+      Path_Instance : Iir;
+
+      --  The suffix
+      Suffix : String (1 .. Len);
+   end record;
+
+   function Get_Path_Instance_Name_Suffix (Attr : Iir)
+                                          return Path_Instance_Name_Type;
 end Evaluation;
diff --git a/translate/ghdldrv/ghdlrun.adb b/translate/ghdldrv/ghdlrun.adb
index fb05df789..7dbce3ded 100644
--- a/translate/ghdldrv/ghdlrun.adb
+++ b/translate/ghdldrv/ghdlrun.adb
@@ -304,13 +304,10 @@ package body Ghdlrun is
       Def (Trans_Decls.Ghdl_Now,
            Grt.Types.Current_Time'Address);
 
-      Def (Trans_Decls.Ghdl_Signal_Active_Chain,
-           Grt.Signals.Ghdl_Signal_Active_Chain'Address);
-
       Def (Trans_Decls.Ghdl_Process_Add_Driver,
            Grt.Signals.Ghdl_Process_Add_Driver'Address);
-      Def (Trans_Decls.Ghdl_Signal_Direct_Driver,
-           Grt.Signals.Ghdl_Signal_Direct_Driver'Address);
+      Def (Trans_Decls.Ghdl_Signal_Add_Direct_Driver,
+           Grt.Signals.Ghdl_Signal_Add_Direct_Driver'Address);
 
       Def (Trans_Decls.Ghdl_Signal_Add_Source,
            Grt.Signals.Ghdl_Signal_Add_Source'Address);
@@ -366,6 +363,9 @@ package body Ghdlrun is
       Def (Trans_Decls.Ghdl_Signal_Start_Assign_Null,
            Grt.Signals.Ghdl_Signal_Start_Assign_Null'Address);
 
+      Def (Trans_Decls.Ghdl_Signal_Direct_Assign,
+           Grt.Signals.Ghdl_Signal_Direct_Assign'Address);
+
       Def (Trans_Decls.Ghdl_Create_Signal_B2,
            Grt.Signals.Ghdl_Create_Signal_B2'Address);
       Def (Trans_Decls.Ghdl_Signal_Init_B2,
diff --git a/translate/ghdldrv/ghdlsimul.adb b/translate/ghdldrv/ghdlsimul.adb
index d2a7772c9..a3f20ae69 100644
--- a/translate/ghdldrv/ghdlsimul.adb
+++ b/translate/ghdldrv/ghdlsimul.adb
@@ -48,6 +48,9 @@ with Grtlink;
 
 package body Ghdlsimul is
 
+   --  FIXME: reuse simulation.top_config
+   Top_Conf : Iir;
+
    procedure Compile_Init (Analyze_Only : Boolean) is
    begin
       if Analyze_Only then
@@ -72,6 +75,11 @@ package body Ghdlsimul is
    procedure Compile_Elab
      (Cmd_Name : String; Args : Argument_List; Opt_Arg : out Natural)
    is
+      use Name_Table;
+      use Types;
+
+      First_Id : Name_Id;
+      Sec_Id : Name_Id;
    begin
       Extract_Elab_Unit (Cmd_Name, Args, Opt_Arg);
 
@@ -82,6 +90,31 @@ package body Ghdlsimul is
          --  This may happen (bad entity for example).
          raise Compilation_Error;
       end if;
+
+      First_Id := Get_Identifier (Prim_Name.all);
+      if Sec_Name = null then
+         Sec_Id := Null_Identifier;
+      else
+         Sec_Id := Get_Identifier (Sec_Name.all);
+      end if;
+      Top_Conf := Configuration.Configure (First_Id, Sec_Id);
+      if Top_Conf = Null_Iir then
+         raise Compilation_Error;
+      end if;
+
+      --  Check (and possibly abandon) if entity can be at the top of the
+      --  hierarchy.
+      declare
+         Conf_Unit : constant Iir := Get_Library_Unit (Top_Conf);
+         Arch : constant Iir :=
+           Get_Block_Specification (Get_Block_Configuration (Conf_Unit));
+         Entity : constant Iir := Get_Entity (Arch);
+      begin
+         Configuration.Check_Entity_Declaration_Top (Entity);
+         if Nbr_Errors > 0 then
+            raise Compilation_Error;
+         end if;
+      end;
    end Compile_Elab;
 
    --  Set options.
@@ -114,6 +147,8 @@ package body Ghdlsimul is
             Simulation.Trace_Simulation := True;
          elsif Arg.all = "--trace-stmt" then
             Execution.Trace_Statements := True;
+         elsif Arg.all = "--stats" then
+            Simulation.Disp_Stats := True;
          elsif Arg.all = "-i" then
             Simulation.Flag_Interractive := True;
          else
@@ -133,26 +168,8 @@ package body Ghdlsimul is
       end loop;
    end Set_Run_Options;
 
-   procedure Run
-   is
-      use Name_Table;
-      use Types;
-
-      First_Id : Name_Id;
-      Sec_Id : Name_Id;
-      Top_Conf : Iir;
+   procedure Run is
    begin
-      First_Id := Get_Identifier (Prim_Name.all);
-      if Sec_Name = null then
-         Sec_Id := Null_Identifier;
-      else
-         Sec_Id := Get_Identifier (Sec_Name.all);
-      end if;
-      Top_Conf := Configuration.Configure (First_Id, Sec_Id);
-      if Top_Conf = Null_Iir then
-         raise Compilation_Error;
-      end if;
-
       Grtlink.Flag_String := Flags.Flag_String;
 
       Simulation.Simulation_Entity (Top_Conf);
diff --git a/translate/grt/grt-signals.adb b/translate/grt/grt-signals.adb
index dfcda9694..8b8953efa 100644
--- a/translate/grt/grt-signals.adb
+++ b/translate/grt/grt-signals.adb
@@ -173,6 +173,7 @@ package body Grt.Signals is
                               Has_Active => False,
                               Sig_Kind => Sig_Kind,
 
+                              Is_Direct_Active => False,
                               Mode => Mode,
                               Flags => (Propag => Propag_None,
                                         Is_Dumped => False,
@@ -336,8 +337,8 @@ package body Grt.Signals is
       end if;
    end Ghdl_Process_Add_Driver;
 
-   procedure Ghdl_Signal_Direct_Driver (Sign : Ghdl_Signal_Ptr;
-                                        Drv : Ghdl_Value_Ptr)
+   procedure Ghdl_Signal_Add_Direct_Driver (Sign : Ghdl_Signal_Ptr;
+                                            Drv : Ghdl_Value_Ptr)
    is
       Trans : Transaction_Acc;
       Trans1 : Transaction_Acc;
@@ -360,7 +361,7 @@ package body Grt.Signals is
                                  Val_Ptr => Drv);
       Sign.S.Drivers (Sign.S.Nbr_Drivers - 1).Last_Trans := Trans1;
       Trans.Next := Trans1;
-   end Ghdl_Signal_Direct_Driver;
+   end Ghdl_Signal_Add_Direct_Driver;
 
    procedure Append_Port (Targ : Ghdl_Signal_Ptr; Src : Ghdl_Signal_Ptr)
    is
@@ -505,6 +506,32 @@ package body Grt.Signals is
       return null;
    end Get_Driver;
 
+   --  Return TRUE iff SIG has a future transaction for the current time,
+   --  ie iff SIG will be active in the next delta cycle.  This is used to
+   --  recompute wether SIG must be in the active chain.  SIG must be a user
+   --  signal.
+   function Has_Transaction_In_Next_Delta (Sig : Ghdl_Signal_Ptr)
+                                          return Boolean  is
+   begin
+      if Sig.Is_Direct_Active then
+         return True;
+      end if;
+
+      for I in 1 .. Sig.S.Nbr_Drivers loop
+         declare
+            Trans : constant Transaction_Acc :=
+              Sig.S.Drivers (I - 1).First_Trans.Next;
+         begin
+            if Trans.Kind /= Trans_Direct
+              and then Trans.Time = Current_Time
+            then
+               return True;
+            end if;
+         end;
+      end loop;
+      return False;
+   end Has_Transaction_In_Next_Delta;
+
    --  Unused but well-known signal which always terminate
    --    ghdl_signal_active_chain.
    --  As a consequence, every element of the chain has a link field set to
@@ -707,7 +734,7 @@ package body Grt.Signals is
             --  the chain is simply linked), but that issue doesn't appear
             --  frequently.
             if Sign.Link /= null
-              and then Driver.First_Trans.Next.Time /= Current_Time
+              and then not Has_Transaction_In_Next_Delta (Sign)
             then
                if Ghdl_Signal_Active_Chain = Sign then
                   --  At the head of the chain.
@@ -767,6 +794,17 @@ package body Grt.Signals is
       Driver.Last_Trans := Trans;
    end Ghdl_Signal_Next_Assign;
 
+   procedure Ghdl_Signal_Direct_Assign (Sign : Ghdl_Signal_Ptr) is
+   begin
+      if Sign.Link = null then
+         Sign.Link := Grt.Threads.Atomic_Insert
+           (Ghdl_Signal_Active_Chain'access, Sign);
+      end if;
+
+      --  Must be always set (as Sign.Link may be set by a regular driver).
+      Sign.Is_Direct_Active := True;
+   end Ghdl_Signal_Direct_Assign;
+
    procedure Ghdl_Signal_Simple_Assign_Error (Sign : Ghdl_Signal_Ptr;
                                               File : Ghdl_C_String;
                                               Line : Ghdl_I32)
@@ -2624,6 +2662,7 @@ package body Grt.Signals is
 
    Clear_List : Ghdl_Signal_Ptr := null;
 
+   --  Mark SIG as active and put it on Clear_List (if not already).
    procedure Mark_Active (Sig : Ghdl_Signal_Ptr);
    pragma Inline (Mark_Active);
 
@@ -3055,6 +3094,7 @@ package body Grt.Signals is
       --  1) Reset active flag.
       Reset_Active_Flag;
 
+      --  For each active signals
       Sig := Ghdl_Signal_Active_Chain;
       Ghdl_Signal_Active_Chain := Signal_End;
       while Sig.S.Mode_Sig /= Mode_End loop
@@ -3083,6 +3123,7 @@ package body Grt.Signals is
 
             when Net_One_Direct =>
                Mark_Active (Sig);
+               Sig.Is_Direct_Active := False;
 
                Trans := Sig.S.Drivers (0).Last_Trans;
                Direct_Assign (Sig.Driving_Value, Trans.Val_Ptr, Sig.Mode);
@@ -3092,6 +3133,7 @@ package body Grt.Signals is
             when Net_One_Resolved =>
                --  This signal is active.
                Mark_Active (Sig);
+               Sig.Is_Direct_Active := False;
 
                for J in 1 .. Sig.S.Nbr_Drivers loop
                   Trans := Sig.S.Drivers (J - 1).First_Trans.Next;
@@ -3112,6 +3154,7 @@ package body Grt.Signals is
                Internal_Error ("update_signals: no_signal_net");
 
             when others =>
+               Sig.Is_Direct_Active := False;
                if not Propagation.Table (Sig.Net).Updated then
                   Propagation.Table (Sig.Net).Updated := True;
                   Run_Propagation (Sig.Net + 1);
@@ -3324,6 +3367,7 @@ package body Grt.Signals is
                                      Event => False,
                                      Active => False,
                                      Has_Active => False,
+                                     Is_Direct_Active => False,
                                      Sig_Kind => Kind_Signal_No,
                                      Mode => Mode_B2,
 
diff --git a/translate/grt/grt-signals.ads b/translate/grt/grt-signals.ads
index eac47a782..875d8769f 100644
--- a/translate/grt/grt-signals.ads
+++ b/translate/grt/grt-signals.ads
@@ -275,18 +275,13 @@ package Grt.Signals is
    pragma Pack (Ghdl_Signal_Flags);
 
    type Ghdl_Signal is record
-      --  Fields known by ghdl.
+      --  Fields known by the compilers.
       Value : Value_Union;
       Driving_Value : Value_Union;
       Last_Value : Value_Union;
       Last_Event : Std_Time;
       Last_Active : Std_Time;
 
-      --  Chain of signals.
-      --  Used to build nets.
-      --  This is also the simply linked list of future active signals.
-      Link : Ghdl_Signal_Ptr;
-
       Event : Boolean;
       Active : Boolean;
       --  If set, the activity of the signal is required by the user.
@@ -295,6 +290,9 @@ package Grt.Signals is
       --  Internal fields.
       --  NOTE: keep above fields (components) in sync with translation.
 
+      --  If set, the signal has an active direct driver.
+      Is_Direct_Active : Boolean;
+
       --  Kind of the signal (none, bus or register).
       Sig_Kind : Kind_Signal_Type;
 
@@ -307,7 +305,12 @@ package Grt.Signals is
       --  Net of the signal.
       Net : Signal_Net_Type;
 
-      --  Chain of signals whose active flag was set.  Used to clear it.
+      --  Chain of signals that will be active in the next delta-cycle.
+      --  (Also used to build nets).
+      Link : Ghdl_Signal_Ptr;
+
+      --  Chain of signals whose active flag was set.  Used to clear the active
+      --  flag at the end of the delta cycle.
       Alink : Ghdl_Signal_Ptr;
 
       --  Chain of signals that have a projected waveform in the real future.
@@ -530,6 +533,8 @@ package Grt.Signals is
                                             File : Ghdl_C_String;
                                             Line : Ghdl_I32);
 
+   procedure Ghdl_Signal_Direct_Assign (Sign : Ghdl_Signal_Ptr);
+
    procedure Ghdl_Signal_Set_Disconnect (Sign : Ghdl_Signal_Ptr;
                                          Time : Std_Time);
 
@@ -652,9 +657,15 @@ package Grt.Signals is
    --  Add a driver to SIGN for the current process.
    procedure Ghdl_Process_Add_Driver (Sign : Ghdl_Signal_Ptr);
 
-   --  Add a direct driver for the current process.
-   procedure Ghdl_Signal_Direct_Driver (Sign : Ghdl_Signal_Ptr;
-                                        Drv : Ghdl_Value_Ptr);
+   --  Add a direct driver for the current process.  This is an optimization
+   --  that could be used when a driver has no projected waveforms.
+   --
+   --  Assignment using direct driver:
+   --  * the driver value is set
+   --  * put the signal on the ghdl_signal_active_chain, if the signal will
+   --    be active and if not already on the chain.
+   procedure Ghdl_Signal_Add_Direct_Driver (Sign : Ghdl_Signal_Ptr;
+                                            Drv : Ghdl_Value_Ptr);
 
    --  Used for connexions:
    --  SRC is a source for TARG.
@@ -759,6 +770,9 @@ private
    pragma Export (C, Ghdl_Signal_Start_Assign_Null,
                   "__ghdl_signal_start_assign_null");
 
+   pragma Export (C, Ghdl_Signal_Direct_Assign,
+                  "__ghdl_signal_direct_assign");
+
    pragma Export (C, Ghdl_Signal_Set_Disconnect,
                   "__ghdl_signal_set_disconnect");
    pragma Export (C, Ghdl_Signal_Disconnect,
@@ -859,8 +873,8 @@ private
 
    pragma Export (C, Ghdl_Process_Add_Driver,
                   "__ghdl_process_add_driver");
-   pragma Export (C, Ghdl_Signal_Direct_Driver,
-                  "__ghdl_signal_direct_driver");
+   pragma Export (C, Ghdl_Signal_Add_Direct_Driver,
+                  "__ghdl_signal_add_direct_driver");
 
    pragma Export (C, Ghdl_Signal_Add_Source,
                   "__ghdl_signal_add_source");
diff --git a/translate/trans_decls.ads b/translate/trans_decls.ads
index eadba8bde..23bd6d9dc 100644
--- a/translate/trans_decls.ads
+++ b/translate/trans_decls.ads
@@ -49,8 +49,9 @@ package Trans_Decls is
 
    --  Register a driver for a process.
    Ghdl_Process_Add_Driver : O_Dnode;
+   Ghdl_Signal_Add_Direct_Driver : O_Dnode;
 
-   --  NOW variables.
+   --  NOW variable.
    Ghdl_Now : O_Dnode;
 
    --  Protected variables.
@@ -64,6 +65,7 @@ package Trans_Decls is
 
    Ghdl_Signal_Driving : O_Dnode;
 
+   Ghdl_Signal_Direct_Assign : O_Dnode;
 
    Ghdl_Signal_Simple_Assign_Error : O_Dnode;
    Ghdl_Signal_Start_Assign_Error : O_Dnode;
@@ -72,8 +74,6 @@ package Trans_Decls is
    Ghdl_Signal_Start_Assign_Null : O_Dnode;
    Ghdl_Signal_Next_Assign_Null : O_Dnode;
 
-   Ghdl_Signal_Direct_Driver : O_Dnode;
-
    Ghdl_Create_Signal_E8 : O_Dnode;
    Ghdl_Signal_Init_E8 : O_Dnode;
    Ghdl_Signal_Simple_Assign_E8 : O_Dnode;
@@ -138,9 +138,6 @@ package Trans_Decls is
    Ghdl_Signal_Read_Driver : O_Dnode;
    Ghdl_Signal_Read_Port : O_Dnode;
 
-   --  Chain of to be active signals.
-   Ghdl_Signal_Active_Chain : O_Dnode;
-
    --  Signal attribute.
    Ghdl_Create_Stable_Signal : O_Dnode;
    Ghdl_Create_Quiet_Signal : O_Dnode;
diff --git a/translate/translation.adb b/translate/translation.adb
index 4be924a69..4c3360dee 100644
--- a/translate/translation.adb
+++ b/translate/translation.adb
@@ -147,7 +147,6 @@ package body Translation is
    Ghdl_Signal_Last_Value_Field : O_Fnode;
    Ghdl_Signal_Last_Event_Field : O_Fnode;
    Ghdl_Signal_Last_Active_Field : O_Fnode;
-   Ghdl_Signal_Active_Chain_Field : O_Fnode;
    Ghdl_Signal_Event_Field : O_Fnode;
    Ghdl_Signal_Active_Field : O_Fnode;
    Ghdl_Signal_Has_Active_Field : O_Fnode;
@@ -21264,6 +21263,7 @@ package body Translation is
       is
          Targ_Sig : Mnode;
          If_Blk : O_If_Block;
+         Constr : O_Assoc_List;
          Cond : O_Dnode;
          Drv : Mnode;
       begin
@@ -21300,25 +21300,14 @@ package body Translation is
 
          --  Put signal into active list (if not already in the list).
          --  FIXME: this is not thread-safe!
-         Start_If_Stmt
-           (If_Blk,
-            New_Dyadic_Op
-            (ON_And,
-             New_Obj_Value (Cond),
-             New_Compare_Op
-             (ON_Eq,
-              New_Value (Chap14.Get_Signal_Field
-                         (Targ_Sig, Ghdl_Signal_Active_Chain_Field)),
-              New_Lit (New_Null_Access (Ghdl_Signal_Ptr)),
-              Ghdl_Bool_Type)));
-         New_Assign_Stmt
-           (Chap14.Get_Signal_Field (Targ_Sig, Ghdl_Signal_Active_Chain_Field),
-            New_Obj_Value (Ghdl_Signal_Active_Chain));
-         New_Assign_Stmt
-           (New_Obj (Ghdl_Signal_Active_Chain),
-            New_Convert_Ov (New_Value (M2Lv (Targ_Sig)),
-                            Ghdl_Signal_Ptr));
+         Start_If_Stmt (If_Blk, New_Obj_Value (Cond));
+         Start_Association (Constr, Ghdl_Signal_Direct_Assign);
+         New_Association (Constr,
+                          New_Convert_Ov (New_Value (M2Lv (Targ_Sig)),
+                                          Ghdl_Signal_Ptr));
+         New_Procedure_Call (Constr);
          Finish_If_Stmt (If_Blk);
+
          Close_Temp;
       end Gen_Signal_Direct_Assign_Non_Composite;
 
@@ -22590,7 +22579,7 @@ package body Translation is
          pragma Unreferenced (Targ_Type);
          Constr : O_Assoc_List;
       begin
-         Start_Association (Constr, Ghdl_Signal_Direct_Driver);
+         Start_Association (Constr, Ghdl_Signal_Add_Direct_Driver);
          New_Association
            (Constr, New_Convert_Ov (New_Value (M2Lv (Targ)), Ghdl_Signal_Ptr));
          New_Association
@@ -22662,7 +22651,7 @@ package body Translation is
 --           pragma Unreferenced (Sig_Type);
 --           Constr : O_Assoc_List;
 --        begin
---           Start_Association (Constr, Ghdl_Signal_Direct_Driver);
+--           Start_Association (Constr, Ghdl_Signal_Add_Direct_Driver);
 --           New_Association
 --          (Constr, New_Convert_Ov (New_Value (M2Lv (Sig)), Ghdl_Signal_Ptr));
 --           New_Association
@@ -25298,225 +25287,22 @@ package body Translation is
                                 Pinfo.Ortho_Type (Mode_Value));
       end Translate_Value_Attribute;
 
-      --  Current path for name attributes.
-      Path_Str : String_Acc := null;
-      Path_Maxlen : Natural := 0;
-      Path_Len : Natural;
-      Path_Instance : Iir;
-
-      procedure Deallocate is new Ada.Unchecked_Deallocation
-        (Name => String_Acc, Object => String);
-
-      procedure Path_Reset is
-      begin
-         Path_Len := 0;
-         Path_Instance := Null_Iir;
-         if Path_Maxlen = 0 then
-            Path_Maxlen := 256;
-            Path_Str := new String (1 .. Path_Maxlen);
-         end if;
-      end Path_Reset;
-
-      procedure Path_Add (Str : String)
-      is
-         N_Len : Natural;
-         N_Path : String_Acc;
-      begin
-         N_Len := Path_Maxlen;
-         loop
-            exit when Path_Len + Str'Length <= N_Len;
-            N_Len := N_Len * 2;
-         end loop;
-         if N_Len /= Path_Maxlen then
-            N_Path := new String (1 .. N_Len);
-            N_Path (1 .. Path_Len) := Path_Str (1 .. Path_Len);
-            Deallocate (Path_Str);
-            Path_Str := N_Path;
-            Path_Maxlen := N_Len;
-         end if;
-         Path_Str (Path_Len + 1 .. Path_Len + Str'Length) := Str;
-         Path_Len := Path_Len + Str'Length;
-      end Path_Add;
-
-      procedure Path_Add_Type_Name (Atype : Iir)
-      is
-         use Name_Table;
-         Adecl : Iir;
-      begin
-         Adecl := Get_Type_Declarator (Atype);
-         Image (Get_Identifier (Adecl));
-         Path_Add (Name_Buffer (1 .. Name_Length));
-      end Path_Add_Type_Name;
-
-      procedure Path_Add_Signature (Subprg : Iir)
-      is
-         Chain : Iir;
-      begin
-         Path_Add ("[");
-         Chain := Get_Interface_Declaration_Chain (Subprg);
-         while Chain /= Null_Iir loop
-            Path_Add_Type_Name (Get_Type (Chain));
-            Chain := Get_Chain (Chain);
-            if Chain /= Null_Iir then
-               Path_Add (",");
-            end if;
-         end loop;
-
-         case Get_Kind (Subprg) is
-            when Iir_Kind_Function_Declaration
-              | Iir_Kind_Implicit_Function_Declaration =>
-               Path_Add (" return ");
-               Path_Add_Type_Name (Get_Return_Type (Subprg));
-            when others =>
-               null;
-         end case;
-         Path_Add ("]");
-      end Path_Add_Signature;
-
-      procedure Path_Add_Name (N : Iir)
-      is
-         use Name_Table;
-      begin
-         Eval_Simple_Name (Get_Identifier (N));
-         if Name_Buffer (1) /= 'P' then
-            --  Skip anonymous processes.
-            Path_Add (Name_Buffer (1 .. Name_Length));
-         end if;
-      end Path_Add_Name;
-
-      procedure Path_Add_Element (El : Iir; Is_Instance : Boolean)
-      is
-      begin
-         --  LRM 14.1
-         --  E'INSTANCE_NAME
-         --    There is one full pah instance element for each component
-         --    instantiation, block statement, generate statemenent, process
-         --    statement, or subprogram body in the design hierarchy between
-         --    the top design entity and the named entity denoted by the
-         --    prefix.
-         --
-         --  E'PATH_NAME
-         --    There is one path instance element for each component
-         --    instantiation, block statement, generate statement, process
-         --    statement, or subprogram body in the design hierarchy between
-         --    the root design entity and the named entity denoted by the
-         --    prefix.
-         case Get_Kind (El) is
-            when Iir_Kind_Library_Declaration =>
-               Path_Add (":");
-               Path_Add_Name (El);
-               Path_Add (":");
-            when Iir_Kind_Package_Declaration =>
-               Path_Add_Element
-                 (Get_Library (Get_Design_File (Get_Design_Unit (El))),
-                  Is_Instance);
-               Path_Add_Name (El);
-               Path_Add (":");
-            when Iir_Kind_Entity_Declaration =>
-               Path_Instance := El;
-            when Iir_Kind_Architecture_Declaration =>
-               Path_Instance := El;
-            when Iir_Kind_Design_Unit =>
-               Path_Add_Element (Get_Library_Unit (El), Is_Instance);
-            when Iir_Kind_Sensitized_Process_Statement
-              | Iir_Kind_Process_Statement
-              | Iir_Kind_Block_Statement =>
-               Path_Add_Element (Get_Parent (El), Is_Instance);
-               Path_Add_Name (El);
-               Path_Add (":");
-            when Iir_Kind_Function_Declaration
-              | Iir_Kind_Procedure_Declaration
-              | Iir_Kind_Implicit_Function_Declaration
-              | Iir_Kind_Implicit_Procedure_Declaration =>
-               Path_Add_Element (Get_Parent (El), Is_Instance);
-               Path_Add_Name (El);
-               if Flags.Vhdl_Std >= Vhdl_02 then
-                  --  Add signature.
-                  Path_Add_Signature (El);
-               end if;
-               Path_Add (":");
-            when Iir_Kind_Procedure_Body =>
-               Path_Add_Element (Get_Subprogram_Specification (El),
-                                 Is_Instance);
-            when Iir_Kind_Generate_Statement =>
-               declare
-                  Scheme : Iir;
-               begin
-                  Scheme := Get_Generation_Scheme (El);
-                  if Get_Kind (Scheme) = Iir_Kind_Iterator_Declaration then
-                     Path_Instance := El;
-                  else
-                     Path_Add_Element (Get_Parent (El), Is_Instance);
-                     Path_Add_Name (El);
-                     Path_Add (":");
-                  end if;
-               end;
-            when Iir_Kinds_Sequential_Statement =>
-               Path_Add_Element (Get_Parent (El), Is_Instance);
-            when others =>
-               Error_Kind ("path_add_element", El);
-         end case;
-      end Path_Add_Element;
-
       function Translate_Path_Instance_Name_Attribute (Attr : Iir)
                                                       return O_Enode
       is
-         Prefix : Iir;
+         Name : constant Path_Instance_Name_Type :=
+           Get_Path_Instance_Name_Suffix (Attr);
          Res : O_Dnode;
          Name_Cst : O_Dnode;
          Str_Cst : O_Cnode;
          Constr : O_Assoc_List;
-         Is_Instance : Boolean;
+         Is_Instance : constant Boolean :=
+           Get_Kind (Attr) = Iir_Kind_Instance_Name_Attribute;
       begin
-         Prefix := Get_Prefix (Attr);
-         Is_Instance := Get_Kind (Attr) = Iir_Kind_Instance_Name_Attribute;
-
-         Path_Reset;
-
-         --  LRM 14.1
-         --  E'PATH_NAME
-         --    The local item name in E'PATH_NAME equals E'SIMPLE_NAME, unless
-         --    E denotes a library, package, subprogram or label. In this
-         --    latter case, the package based path or instance based path,
-         --    as appropriate, will not contain a local item name.
-         --
-         --  E'INSTANCE_NAME
-         --    The local item name in E'INSTANCE_NAME equals E'SIMPLE_NAME,
-         --    unless E denotes a library, package, subprogram, or label.  In
-         --    this latter case, the package based path or full instance based
-         --    path, as appropriate, will not contain a local item name.
-         case Get_Kind (Prefix) is
-            when Iir_Kind_Constant_Declaration
-              | Iir_Kind_Constant_Interface_Declaration
-              | Iir_Kind_Iterator_Declaration
-              | Iir_Kind_Variable_Declaration
-              | Iir_Kind_Variable_Interface_Declaration
-              | Iir_Kind_Signal_Declaration
-              | Iir_Kind_Signal_Interface_Declaration
-              | Iir_Kind_File_Declaration
-              | Iir_Kind_File_Interface_Declaration
-              | Iir_Kind_Type_Declaration
-              | Iir_Kind_Subtype_Declaration =>
-               Path_Add_Element (Get_Parent (Prefix), Is_Instance);
-               Path_Add_Name (Prefix);
-            when Iir_Kind_Library_Declaration
-              | Iir_Kind_Design_Unit
-              | Iir_Kind_Package_Declaration
-              | Iir_Kind_Function_Declaration
-              | Iir_Kind_Procedure_Declaration
-              | Iir_Kind_Implicit_Function_Declaration
-              | Iir_Kind_Implicit_Procedure_Declaration
-              | Iir_Kinds_Concurrent_Statement
-              | Iir_Kinds_Sequential_Statement =>
-               Path_Add_Element (Prefix, Is_Instance);
-            when others =>
-               Error_Kind ("translate_path_instance_name_attribute", Prefix);
-         end case;
          Create_Temp_Stack2_Mark;
 
          Res := Create_Temp (Std_String_Node);
-         Str_Cst := Create_String_Len (Path_Str (1 .. Path_Len),
-                                       Create_Uniq_Identifier);
+         Str_Cst := Create_String_Len (Name.Suffix, Create_Uniq_Identifier);
          New_Const_Decl (Name_Cst, Create_Uniq_Identifier, O_Storage_Private,
                          Ghdl_Str_Len_Type_Node);
          Start_Const_Value (Name_Cst);
@@ -25528,10 +25314,10 @@ package body Translation is
          end if;
          New_Association
            (Constr, New_Address (New_Obj (Res), Std_String_Ptr_Node));
-         if Path_Instance = Null_Iir then
+         if Name.Path_Instance = Null_Iir then
             Rtis.Associate_Null_Rti_Context (Constr);
          else
-            Rtis.Associate_Rti_Context (Constr, Path_Instance);
+            Rtis.Associate_Rti_Context (Constr, Name.Path_Instance);
          end if;
          New_Association (Constr,
                           New_Address (New_Obj (Name_Cst),
@@ -29106,9 +28892,6 @@ package body Translation is
       New_Record_Field (Rec, Ghdl_Signal_Last_Active_Field,
                         Get_Identifier ("last_active"),
                         Time_Otype);
-      New_Record_Field (Rec, Ghdl_Signal_Active_Chain_Field,
-                        Get_Identifier ("active_chain"),
-                        Ghdl_Signal_Ptr);
       New_Record_Field (Rec, Ghdl_Signal_Event_Field,
                         Get_Identifier ("event"),
                         Std_Boolean_Type_Node);
@@ -29124,11 +28907,6 @@ package body Translation is
       New_Type_Decl (Get_Identifier ("__ghdl_signal_ptr_ptr"),
                      Ghdl_Signal_Ptr_Ptr);
 
-      New_Var_Decl (Ghdl_Signal_Active_Chain,
-                    Get_Identifier ("__ghdl_signal_active_chain"),
-                    O_Storage_External,
-                    Ghdl_Signal_Ptr);
-
       --  procedure __ghdl_signal_merge_rti
       --       (sig : ghdl_signal_ptr; rti : ghdl_rti_access)
       Start_Procedure_Decl
@@ -29370,16 +29148,24 @@ package body Translation is
       New_Interface_Decl (Interfaces, Param, Wki_Sig, Ghdl_Signal_Ptr);
       Finish_Subprogram_Decl (Interfaces, Ghdl_Process_Add_Driver);
 
-      --  procedure __ghdl_signal_direct_driver (sig : __ghdl_signal_ptr;
-      --                                         Drv : Ghdl_Ptr_type);
+      --  procedure __ghdl_signal_add_direct_driver (sig : __ghdl_signal_ptr;
+      --                                             Drv : Ghdl_Ptr_type);
       Start_Procedure_Decl
-        (Interfaces, Get_Identifier ("__ghdl_signal_direct_driver"),
+        (Interfaces, Get_Identifier ("__ghdl_signal_add_direct_driver"),
          O_Storage_External);
       New_Interface_Decl
         (Interfaces, Param, Wki_Sig, Ghdl_Signal_Ptr);
       New_Interface_Decl
         (Interfaces, Param, Get_Identifier ("drv"), Ghdl_Ptr_Type);
-      Finish_Subprogram_Decl (Interfaces, Ghdl_Signal_Direct_Driver);
+      Finish_Subprogram_Decl (Interfaces, Ghdl_Signal_Add_Direct_Driver);
+
+      --  procedure __ghdl_signal_direct_assign (sig : __ghdl_signal_ptr);
+      Start_Procedure_Decl
+        (Interfaces, Get_Identifier ("__ghdl_signal_direct_assign"),
+         O_Storage_External);
+      New_Interface_Decl
+        (Interfaces, Param, Wki_Sig, Ghdl_Signal_Ptr);
+      Finish_Subprogram_Decl (Interfaces, Ghdl_Signal_Direct_Assign);
 
       declare
          procedure Create_Signal_Conversion (Name : String; Res : out O_Dnode)
@@ -29925,47 +29711,6 @@ package body Translation is
                                O_Storage_Public);
       end Gen_Setup_Info;
 
-      --  Return TRUE iff ENTITY can be at the top of a hierarchy, ie:
-      --  ENTITY has no generics or all generics have a default expression
-      --  ENTITY has no ports or all ports type are constrained.
-      procedure Check_Entity_Declaration_Top (Entity : Iir_Entity_Declaration)
-      is
-         Has_Error : Boolean := False;
-
-         procedure Error (Msg : String; Loc : Iir) is
-         begin
-            if not Has_Error then
-               Error_Msg_Elab
-                 (Disp_Node (Entity) & " cannot be at the top of a design");
-               Has_Error := True;
-            end if;
-            Error_Msg_Elab (Msg, Loc);
-         end Error;
-
-         El : Iir;
-      begin
-         --  Check generics.
-         El := Get_Generic_Chain (Entity);
-         while El /= Null_Iir loop
-            if Get_Default_Value (El) = Null_Iir then
-               Error ("(" & Disp_Node (El) & " has no default value)", El);
-            end if;
-            El := Get_Chain (El);
-         end loop;
-
-         --  Check port.
-         El := Get_Port_Chain (Entity);
-         while El /= Null_Iir loop
-            if not Is_Fully_Constrained_Type (Get_Type (El))
-              and then Get_Default_Value (El) = Null_Iir
-            then
-               Error ("(" & Disp_Node (El)
-                      & " is unconstrained and has no default value)", El);
-            end if;
-            El := Get_Chain (El);
-         end loop;
-      end Check_Entity_Declaration_Top;
-
       procedure Gen_Last_Arch (Entity : Iir_Entity_Declaration)
       is
          Entity_Info : Block_Info_Acc;