src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/graphbuilderconf/NodePlugin.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2018, 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
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -219,10 +219,13 @@
      * insertion point is not changed by this call. This means nodes must be added to the graph with
      * the appropriate method (e.g., {@link StructuredGraph#unique} for {@link ValueNumberable}
      * nodes) and fixed nodes must be manually {@linkplain FixedWithNextNode#setNext added} as
      * successors of {@code afterExceptionLoaded}.
      *
+     * The reason for this constraint is that when this plugin runs, it's inserting instructions
+     * into a different block than the one currently being parsed.
+     *
      * @param graph the graph being parsed
      * @param afterExceptionLoaded the last fixed node after loading the exception
      * @return the last fixed node after instrumentation
      */
     default FixedWithNextNode instrumentExceptionDispatch(StructuredGraph graph, FixedWithNextNode afterExceptionLoaded) {