If you haven't received your W-2 by February 14, you need to follow the steps here below.
Get your last 2016 paystub and call the IRS at 1-800-829-1040.
The IRS will ask you for some info before following up with your employer.
After notifying the IRS, you can either continue waiting for your W-2, or paper-file your return using Form 4852 and your last paystub. You can find instructions for how to file with Form 4852 here https://ttlc.intuit.com/questions/3351348