iOS 64-bit app Doubles in Size

Question

I just submitted an app update to the iOS AppStore with 64-bit and 32-bit compatibility. I haven't changed anything except the 64-bit architecture, however the app size is now almost doubled from a pre-64-bit size of 2.7 MB to 4.5 MB.

Is this normal when compiling the app for both 64-bit and 32-bit iOS devices? Why does this happen (anyone care to explain in technical terms)? Or did something funky just happen in Xcode?

Selfsufficient

Answer 1

It's pretty normal because the code is compiled twice - once for 32 and once for 64-bit architectures.

See more information http://www.idownloadblog.com/2013/09/16/apple-to-devs-we-want-your-64-bit-apps-asap/

Tumor

Unless something has changed in the App Store, a device will download a fat binary, which contains both 32-bit and 64-bit architectures. This is necessary because you can sync that binary to iTunes, and then to another device. Only one architecture will be loaded when ran, however. – Aftertaste

@Aftertaste Googled a bit and removed the 2nd part of my answer. It seems te me Apple is not finished with the 32/64 updates yet. – Tumor

Fat binaries aren't new to 32/64. This is now the 4th architecture that iOS devices support (previously we had armv6, armv7, and armv7s). Due to the ability to sync back to iTunes and other devices after purchase, the App Store has to download all architectures (this occurs for Apple apps distributed on the store as well). Only the bundled OS apps are stripped of non-needed resources and architecture (as they don't need to sync, they are always updated via OS updates). – Aftertaste