[abalone]

> However, there is one thing I've never seen mentioned - a combined Mac/iOS binary.

Because they're already doing something better. All iOS apps compile to Bitcode, an intermediary representation that can then compile an optimized binary for the target device architecture.[1]

So if there ever were a desire to run iOS apps on Mac, they'd just compile from Bitcode. Having said that, there's explicitly zero desire to do this.

[1] https://developer.apple.com/library/content/documentation/ID...

[syncsynchalt]

Bitcode allows you to optimize between chip versions with different opcodes, but not different architectures, word sizes, or endianness.

Source: the recent Accidental Tech Podcast that interviewed Chris Lattner.

[abalone]

Ok fine, but the broader App Thinning featureset of the App Store still means they wouldn't do a universal binary. They'd deliver just what the target device needs.

[gpderetta]

True, but AArch64 vs AMD64 are not so different (64 bits, little endian, probably quite similar ABIs), it is not unthinkable that the same bitcode could target both architectures.