--- old/make/gensrc/GensrcModuleLoaderMap.gmk	2020-03-23 19:56:32.871962729 +0100
+++ new/make/gensrc/GensrcModuleLoaderMap.gmk	2020-03-23 19:56:32.535962732 +0100
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2015, 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -41,6 +41,10 @@
 VARDEPS_VALUE := $(BOOT_MODULES_LIST) $(PLATFORM_MODULES_LIST)
 VARDEPS_FILE := $(call DependOnVariable, VARDEPS_VALUE)
 
+TOOL_GENCLASSLOADERMAP = $(JAVA_SMALL) \
+    -cp $(call PathList, $(BUILDTOOLS_OUTPUTDIR)/jdk_tools_classes) \
+    org.openjdk.buildtools.moduleloadermap.GenModuleLoaderMap
+
 ############################################################################
 
 $(SUPPORT_OUTPUTDIR)/gensrc/java.base/jdk/internal/module/ModuleLoaderMap.java: \