Handle Address representation clauses

Use more General Exp_Value rather than IntVal
to determine value of "Size" and "Component_Size"
IntVal expects an integer literal whereas Exp_Value
will accept a static expression and return its
folded value.

Author: tjj2017

gnat2goto/driver/tree_walk.adb

@@ -1,6 +1,7 @@
 with Namet;                 use Namet;
 with Nlists;                use Nlists;
 with Sem;
+with Sem_Eval;              use Sem_Eval;
 with Sem_Util;              use Sem_Util;
 with Sem_Aux;               use Sem_Aux;
 with Snames;                use Snames;
@@ -4644,51 +4645,70 @@ package body Tree_Walk is
       procedure Handle_Representation_Clause (N : Node_Id);
       procedure Handle_Representation_Clause (N : Node_Id) is
          Attr_Id : constant String := Get_Name_String (Chars (N));
-         Target_Name : constant Irep := Do_Identifier (Name (N));
-         Entity_Esize : constant Uint := Esize (Entity (N));
-         Target_Type_Irep : constant Irep :=
-           Follow_Symbol_Type (Get_Type (Target_Name), Global_Symbol_Table);
-         Expression_Value : constant Uint := Intval (Expression (N));
       begin
-         pragma Assert (Kind (Target_Type_Irep) in Class_Type);
-         if Attr_Id = "size" then
-
-            --  Just check that the front-end already applied this size
-            --  clause, i .e. that the size of type-irep we already had
-            --  equals the entity type this clause is applied to (and the
-            --  size specified in this clause).
-            pragma Assert (Entity_Esize =
-                             UI_From_Int (Int (Get_Width (Target_Type_Irep)))
-                           and Entity_Esize = Expression_Value);
+         --  First check if it is an address clause which gnat2goto does not
+         --  currently handle
+         if Attr_Id = "address" then
+            Report_Unhandled_Node_Empty
+              (N, "Process_Declaration",
+               "Address representation clauses are not currently supported");
             return;
-         elsif Attr_Id = "component_size" then
-            if not Is_Array_Type (Entity (N)) then
-               Report_Unhandled_Node_Empty (N, "Process_Declaration",
-                              "Component size only supported for array types");
-               return;
-            end if;
+         elsif Attr_Id = "size" or else Attr_Id = "component_size" then
             declare
-               Array_Data : constant Irep :=
-                 Get_Data_Component_From_Type (Target_Type_Irep);
-               Target_Subtype : constant Irep :=
-                 Follow_Symbol_Type (Get_Subtype (Get_Type (Array_Data)),
-                                     Global_Symbol_Table);
-               Target_Subtype_Width : constant Uint :=
-                 UI_From_Int (Int (Get_Width (Target_Subtype)));
+               Target_Name : constant Irep := Do_Identifier (Name (N));
+               Entity_Esize : constant Uint := Esize (Entity (N));
+               Target_Type_Irep : constant Irep :=
+                 Follow_Symbol_Type
+                   (Get_Type (Target_Name), Global_Symbol_Table);
+               Expression_Value : constant Uint := Expr_Value (Expression (N));
             begin
-               if Component_Size (Entity (N)) /= Expression_Value or
-                 Target_Subtype_Width /= Expression_Value
-               then
-                  Report_Unhandled_Node_Empty (N, "Process_Declaration",
-                      "Having component sizes be different from the size of " &
-                      "their underlying type is currently not supported");
+               pragma Assert (Kind (Target_Type_Irep) in Class_Type);
+               if Attr_Id = "size" then
+
+                  --  Just check that the front-end already applied this size
+                  --  clause, i .e. that the size of type-irep we already had
+                  --  equals the entity type this clause is applied to (and the
+                  --  size specified in this clause).
+                  pragma Assert
+                    (Entity_Esize =
+                       UI_From_Int (Int (Get_Width (Target_Type_Irep)))
+                     and Entity_Esize = Expression_Value);
+                  return;
+               elsif Attr_Id = "component_size" then
+                  if not Is_Array_Type (Entity (N)) then
+                     Report_Unhandled_Node_Empty
+                       (N, "Process_Declaration",
+                        "Component size only supported for array types");
+                     return;
+                  end if;
+                  declare
+                     Array_Data : constant Irep :=
+                       Get_Data_Component_From_Type (Target_Type_Irep);
+                     Target_Subtype : constant Irep :=
+                       Follow_Symbol_Type (Get_Subtype (Get_Type (Array_Data)),
+                                           Global_Symbol_Table);
+                     Target_Subtype_Width : constant Uint :=
+                       UI_From_Int (Int (Get_Width (Target_Subtype)));
+                  begin
+                     if Component_Size (Entity (N)) /= Expression_Value or
+                       Target_Subtype_Width /= Expression_Value
+                     then
+                        Report_Unhandled_Node_Empty
+                          (N, "Process_Declaration",
+                           "Having component sizes be different from the "
+                           & "size of their underlying type "
+                           & "is currently not supported");
+                     end if;
+                  end;
+                  return;
                end if;
             end;
-            return;
          end if;
 
-         Report_Unhandled_Node_Empty (N, "Process_Declaration",
-                              "Representation clause unsupported: " & Attr_Id);
+         Report_Unhandled_Node_Empty
+           (N, "Process_Declaration",
+            "Representation clause unsupported: " & Attr_Id);
+
       end Handle_Representation_Clause;
 
    begin