A simple invokedynamic example, invoking a virtual method (Object.toString), with BiteScript. Code modified from BiteScript's example/invokedynamic.bs

myindytest.bs

import java.lang.invoke.MethodHandle
import java.lang.invoke.MethodType
import java.lang.invoke.CallSite
import java.lang.invoke.ConstantCallSite
import java.lang.invoke.MethodHandles::Lookup
JClass = java.lang.Class
JInteger = java.lang.Integer

# Our main method, which does one invokedynamic
main do
  # handle for our bootstrap, which binds invokedynamic to a CallSite
  bootstrap = mh_invokestatic this, :bootstrap, CallSite, Lookup, string, MethodType

  push_int 12345
  invokestatic JInteger, :valueOf, [JInteger, int]
  invokedynamic :_, [string, object], bootstrap
  invokestatic this, :print, [void, string]
  returnvoid
end

# The method we want to invoke, prints given string
public_static_method :print, [], void, string do
  aload 0
  aprintln
  returnvoid
end

# The bootstrap method, which binds our dynamic call
public_static_method :bootstrap, [], CallSite, Lookup, string, MethodType do
  # Constant since we bind just once directly
  new ConstantCallSite
  dup

  # Locate the method indicated by name + type on current class
  aload 0         # Lookup
  ldc object      # this class
  ldc 'toString'  # String
  ldc string      # MethodType
  invokestatic MethodType, :methodType, [MethodType, JClass]
  invokevirtual Lookup, :findVirtual, [MethodHandle, JClass, string, MethodType]
  
  # adapt the method handle to appropriate type
  aload 2
  invokevirtual MethodHandle, :asType, [MethodHandle, MethodType]

  # finish constructing call site and return
  invokespecial ConstantCallSite, '<init>', [void, MethodHandle]
  areturn
end