// this implements the upcall from the JVM, MethodHandleNatives.makeDynamicCallSite:

    static CallSite makeSite(MethodHandle bootstrapMethod,

                             // Callee information:

                             String name, MethodType type,

                             // Call-site attributes, if any:

                             Object info,

                             // Caller information:

                             MemberName callerMethod, int callerBCI) {

        Class<?> caller = callerMethod.getDeclaringClass();

        if (bootstrapMethod == null) {

            // If there is no bootstrap method, throw IncompatibleClassChangeError.

            // This is a valid generic error type for resolution (JLS 12.3.3).

            throw new IncompatibleClassChangeError

                ("Class "+caller.getName()+" has not declared a bootstrap method for invokedynamic");

        }

            if (bootstrapMethod.type().parameterCount() == 3)

                site = bootstrapMethod.<CallSite>invokeExact(caller, name, type);

            else if (bootstrapMethod.type().parameterCount() == 4)

                site = bootstrapMethod.<CallSite>invokeExact(caller, name, type,

                                                             !(info instanceof java.lang.annotation.Annotation[]) ? null

                                                             : (java.lang.annotation.Annotation[]) info);

            else

                throw new InternalError("bad BSM: "+bootstrapMethod);

            if (!(site instanceof CallSite))

                throw new InvokeDynamicBootstrapError("class bootstrap method failed to create a call site: "+caller);

            PRIVATE_INITIALIZE_CALL_SITE.<void>invokeExact(site,

                                                           name, type,

                                                           callerMethod, callerBCI);

            assert(site.getTarget() != null);

            assert(site.getTarget().type().equals(type));

            InvokeDynamicBootstrapError bex;

            if (ex instanceof InvokeDynamicBootstrapError)

                bex = (InvokeDynamicBootstrapError) ex;

            else

                bex = new InvokeDynamicBootstrapError("call site initialization exception", ex);

            throw bex;

    // This method is private in CallSite because it touches private fields in CallSite.

    // These private fields (vmmethod, vmindex) are specific to the JVM.

    private static final MethodHandle PRIVATE_INITIALIZE_CALL_SITE =

            MethodHandleImpl.IMPL_LOOKUP.findVirtual(CallSite.class, "initializeFromJVM",

                MethodType.methodType(void.class,

                                      String.class, MethodType.class,

                                      MemberName.class, int.class));

    public static void setCallSiteTarget(Access token, CallSite site, MethodHandle target) {

        Access.check(token);

        MethodHandleNatives.setCallSiteTarget(site, target);

    }