presto-main/src/main/java/io/prestosql/sql/gen/OrderingCompiler.java/OrderingCompiler/internalCompilePageWithPositionComparator
class OrderingCompiler:    private PageWithPositionComparator internalCompilePageWithPositionComparator(List<Type> types, List<Integer> sortChannels, List<SortOrder> sortOrders)
    {
        PageWithPositionComparator comparator;
        try {
            Class<? extends PageWithPositionComparator> pageWithPositionsComparatorClass = generatePageWithPositionComparatorClass(types, sortChannels, sortOrders);
            comparator = pageWithPositionsComparatorClass.getConstructor().newInstance();
        }
        catch (Throwable t) {
            log.error(t, "Error compiling comparator for channels %s with order %s", sortChannels, sortChannels);
            comparator = new SimplePageWithPositionComparator(types, sortChannels, sortOrders);
        }
        return comparator;
    }