presto-main/src/main/java/io/prestosql/sql/gen/InvokeFunctionBytecodeExpression.java/InvokeFunctionBytecodeExpression/invokeFunction
class InvokeFunctionBytecodeExpression:    public static BytecodeExpression invokeFunction(Scope scope, CachedInstanceBinder cachedInstanceBinder, String name, ScalarFunctionImplementation function, List<BytecodeExpression> parameters)
    {
        requireNonNull(scope, "scope is null");
        requireNonNull(function, "function is null");

        Optional<BytecodeNode> instance = Optional.empty();
        if (function.getInstanceFactory().isPresent()) {
            FieldDefinition field = cachedInstanceBinder.getCachedInstance(function.getInstanceFactory().get());
            instance = Optional.of(scope.getThis().getField(field));
        }
        return new InvokeFunctionBytecodeExpression(scope, cachedInstanceBinder.getCallSiteBinder(), name, function, instance, parameters);
    }