--- old/src/hotspot/share/utilities/constantTag.cpp	2018-09-28 11:53:57.000000000 -0700
+++ new/src/hotspot/share/utilities/constantTag.cpp	2018-09-28 11:53:57.000000000 -0700
@@ -68,6 +68,31 @@
 }
 
 
+// value as specified in the classfile format
+jbyte constantTag::classfile_value() const {
+  switch (_tag) {
+  case JVM_CONSTANT_ClassIndex:
+  case JVM_CONSTANT_UnresolvedClass:
+  case JVM_CONSTANT_UnresolvedClassInError:
+    return JVM_CONSTANT_Class;
+  case JVM_CONSTANT_StringIndex:
+    return JVM_CONSTANT_String;
+  case JVM_CONSTANT_MethodHandleInError:
+    return JVM_CONSTANT_MethodHandle;
+  case JVM_CONSTANT_MethodTypeInError:
+    return JVM_CONSTANT_MethodType;
+  case JVM_CONSTANT_DynamicInError:
+    return JVM_CONSTANT_Dynamic;
+  default:
+    // Return a zero tag for a gap after Long or Double,
+    // even though that doesn't exactly appear in a classfile.
+    assert(_tag >= 0 && _tag <= JVM_CONSTANT_ExternalMax,
+           "cannot interpret tag %d as a standard classfile tag", _tag);
+    return _tag;
+  }
+}
+
+
 jbyte constantTag::non_error_value() const {
   switch (_tag) {
   case JVM_CONSTANT_UnresolvedClassInError: