The constant dynamic changes in JDK-8186209 updated MethodHandleNatives.linkCallSite to take an int parameter `indexInCP` that is passed up from the VM, but it is not actually used:

From: http://hg.openjdk.java.net/jdk/jdk/rev/c4d9d1b08e2e

@@ -228,6 +234,7 @@
      * The JVM is linking an invokedynamic instruction. Create a reified call site for it.
      */
     static MemberName linkCallSite(Object callerObj,
+ int indexInCP,
                                    Object bootstrapMethodObj,
                                    Object nameObj, Object typeObj,
                                    Object staticArguments,

@@ -268,9 +275,7 @@
                                           Object[] appendixResult) {
         Object bsmReference = bootstrapMethod.internalMemberName();
         if (bsmReference == null) bsmReference = bootstrapMethod;
- Object staticArglist = (staticArguments instanceof Object[] ?
- java.util.Arrays.asList((Object[]) staticArguments) :
- staticArguments);
+ String staticArglist = staticArglistForTrace(staticArguments);
         System.out.println("linkCallSite "+caller.getName()+" "+
                            bsmReference+" "+
                            name+type+"/"+staticArglist);

@@ -280,11 +285,89 @@
             System.out.println("linkCallSite => "+res+" + "+appendixResult[0]);
             return res;
         } catch (Throwable ex) {
+ ex.printStackTrace(); // print now in case exception is swallowed
             System.out.println("linkCallSite => throw "+ex);
             throw ex;
         }
     }
 
+ // this implements the upcall from the JVM, MethodHandleNatives.linkDynamicConstant:
+ static Object linkDynamicConstant(Object callerObj,
+ int indexInCP,
+ Object bootstrapMethodObj,
+ Object nameObj, Object typeObj,
+ Object staticArguments) {
+ MethodHandle bootstrapMethod = (MethodHandle)bootstrapMethodObj;
+ Class<?> caller = (Class<?>)callerObj;
+ String name = nameObj.toString().intern();
+ Class<?> type = (Class<?>)typeObj;
+ if (!TRACE_METHOD_LINKAGE)
+ return linkDynamicConstantImpl(caller, bootstrapMethod, name, type, staticArguments);
+ return linkDynamicConstantTracing(caller, bootstrapMethod, name, type, staticArguments);
+ }

The new indexInCP parameter is not used; nor is it used in the newly added linkDynamicConstant method.