I140 withdrawn/Revoked

[Mtal2rock]

My approved I140 was withdrawn/Revoked by my previous employer, Please find the details : 
H1b start from : Apr 2015 
Currently valid till - Aug 2020 
i140 Approved Date : Dec 29, 2016 
i140 Withdraw/Revoke : November 14th, 2017 

I have completed 6 months, so as per AC21 rule I can retain PD but below are my concerns : 

Will I get indefinite H1b extensions over my withdrawn/Revoked i140 through my current employer for ex. If my current employer will file my extension which is due next year (2020) will I get extension based on withdrawn/Revoked i140( for 2-3 years) or will I get the extension based on my H1b leftover period around 9 months ?? 

Or 

Do my current employer needs to file GC process again(labour + i140) in order to get the future extensions.?