How Can I set UIBarButtonItem as anchor of a popover in IOS?

In iOS 8 & 9, the presentPopoverFromBarButtonItem:permittedArrowDirections:animated: method is deprecated. You'll want to set the barButtonItem property on the view controller's popoverPresentationController property.

let popover = UIViewController()
popover.modalPresentationStyle = .Popover
if let presentation = popover.popoverPresentationController {
    presentation.barButtonItem = navigationItem.rightBarButtonItem
}
presentViewController(popover, animated: true, completion: nil)

You need to use presentPopoverFromBarButtonItem:permittedArrowDirections:animated:.