What is this MODULE_ALIAS() used for?

[Perr Zhang]

source code:

MODULE_ALIAS("platform:sm501");

static const struct of_device_id of_sm501_match_tbl[] = {
    { .compatible = "smi,sm501", },
    { /* end */ }
};
MODULE_DEVICE_TABLE(of, of_sm501_match_tbl);

location: http://lxr.free-electrons.com/source/drivers/mfd/sm501.c#L1711

Since there is the MODULE_DEVICE_TABLE(), why  the author additionally adds the MODULE_ALIAS()?
What exactly is this MODULE_ALIAS() used for?