diff --git a/backends/firrtl/firrtl.cc b/backends/firrtl/firrtl.cc
index fd7f20cc6..40d05a036 100644
--- a/backends/firrtl/firrtl.cc
+++ b/backends/firrtl/firrtl.cc
@@ -306,17 +306,8 @@ struct FirrtlWorker
 		// If this is a parameterized module, its parent module is encoded in the cell type
 		if (cell->type.begins_with("$paramod"))
 		{
-			std::string::iterator it;
-			for (it = cell_type.begin(); it < cell_type.end(); it++)
-			{
-				switch (*it) {
-					case '\\': /* FALL_THROUGH */
-					case '=': /* FALL_THROUGH */
-					case '\'': /* FALL_THROUGH */
-					case '$': instanceOf.append("_"); break;
-					default: instanceOf.append(1, *it); break;
-				}
-			}
+			log_assert(cell->has_attribute(ID::hdlname));
+			instanceOf = cell->get_string_attribute(ID::hdlname);
 		}
 		else
 		{
diff --git a/frontends/ast/ast.cc b/frontends/ast/ast.cc
index 245a53611..de741a506 100644
--- a/frontends/ast/ast.cc
+++ b/frontends/ast/ast.cc
@@ -1565,6 +1565,9 @@ std::string AstModule::derive_common(RTLIL::Design *design, const dict<RTLIL::Id
 	rewritten.reserve(GetSize(parameters));
 
 	AstNode *new_ast = ast->clone();
+	if (!new_ast->attributes.count(ID::hdlname))
+		new_ast->attributes[ID::hdlname] = AstNode::mkconst_str(stripped_name);
+
 	para_counter = 0;
 	for (auto child : new_ast->children) {
 		if (child->type != AST_PARAMETER)
diff --git a/frontends/rpc/rpc_frontend.cc b/frontends/rpc/rpc_frontend.cc
index a23f7548e..46ee6a733 100644
--- a/frontends/rpc/rpc_frontend.cc
+++ b/frontends/rpc/rpc_frontend.cc
@@ -217,6 +217,8 @@ struct RpcModule : RTLIL::Module {
 				module.second->name = mangled_name;
 				module.second->design = design;
 				module.second->attributes.erase(ID::top);
+				if (!module.second->has_attribute(ID::hdlname))
+					module.second->set_string_attribute(ID::hdlname, module.first.str());
 				design->modules_[mangled_name] = module.second;
 				derived_design->modules_.erase(module.first);
 			}