I'm not sure what you mean by iWatch on iPhone. But the latest I hear is the iWatch may not be available until next year in 2015. It's just rumor based on more rumored production woes. But you can check these reports for information regarding rumored features. http://www.everythingicafe.com/iwatch-mass-production/
I would think if their is a watch released along the iPhone that there was some code detected in iOS 8? I think that the wearable Apple releases (if they do release one) with the iPhone will be a sensor loaded device. But a watch? remains to be seen. We know they got the Fitness App. Has anyone seen any parts leak? Any codes at all to suspect a watch? I want a watch and one which works better then the Android wear watches (those stink in so many ways). Anyway if they do release a iWatch it certainly was a well kept secret!