diff -r ef8a98bc71f8 -r c4d9d1b08e2e src/hotspot/share/runtime/signature.hpp
--- a/src/hotspot/share/runtime/signature.hpp	Wed Jan 31 10:55:49 2018 -0800
+++ b/src/hotspot/share/runtime/signature.hpp	Fri Sep 08 10:46:46 2017 -0700
@@ -409,6 +409,11 @@
   const jbyte* raw_bytes()  { return _signature->bytes() + _begin; }
   int          raw_length() { return _end - _begin; }
 
+  jbyte raw_byte_at(int index) {
+    assert(index >= 0 && index < raw_length(), "index overflow");
+    return _signature->byte_at(_begin + index);
+  }
+
   // return same as_symbol except allocation of new symbols is avoided.
   Symbol* as_symbol_or_null();