Bitcode support for iOS frameworks

[anupcowkur]

Hi. Is there a way to generate an iOS framework that has bitcode enabled from the gradle plugin?
Currently ./gradlew build generates iOS frameworks for simulator and device but they don't seem to be bitcode enabled.

[olonho]

Not yet. Why do you need that functionality?

[anupcowkur]

We have a large iOS project that uses bitcode. Xcode requires that if you enable bitcode, all your framework dependencies must also be built with bitcode.

[siuying]

On watchOS/tvOS that’s required. It is also likely in future this would be expanded to iOS.

[anupcowkur]

Bitcode is required to be enabled only in WatchOS but if you have optionally enabled bitcode in your regular app, it is required that all frameworks that are included are also bitcode enabled.

[olonho]

Well, currently we cannot provide bitcode compatible with what Apple needs, so maybe just avoid using bitcode in the meantime.

[kylejbrock]

Is it a technical limitation that would live past 1.0?

[oleksandr-yefremov]

Bitcode is required to be enabled only in WatchOS

This part of statement is not correct. Both tvOS and watchOS require bitcode enabled now.

See https://developer.apple.com/tvos/submit/

When compiling your tvOS app and any third-party libraries, Bitcode must be enabled

So to summarize. Without bitcode you cannot develop any tvOS and watchOS frameworks/apps.
You can build an iOS application, but only as long as Apple does not make it required everywhere.
You can theoretically build an iOS framework with K/N, but you will have to make people disable bitcode in their apps, which is sometimes a blocker.

I completely understand that enabling bitcode is a complex feature, partially because Apple does whatever they want with LLVM. Same issue discussion in rust is open for 1,5 years already and with no ETA. However, IMO, K/N is in better position than Rust, because for Rust iOS support is a low-prio "good to have" feature, whereas K/N is devoted to client side from the beginning. My team is investigating now, whether we could ditch our 2 codebases on Java for Android/AndroidTV and Swift on iOS/tvOS to build one single K/N code and test base for all platforms. Everything looks too good to be true 😄 Except if there is no ETA for bitcode (even in 6 months from now), we won't be able to ship it to customers who use bitcode for a long time now and the whole idea falls apart. K/N FTW! 🏎

(edit): I updated the comment to remove incorrect claim and clarify framework case, sorry about that.

[mouse4d]

I totally agree with @oleksandr-yefremov! We start a new SKD project that is 90% business logic, so we're starting it in Kotlin, with the expectations that it will advance quickly and it will support Bitcode and Dynamic Library in the next time (6 months is good enough). Will be a real blow if it doesn't, but we're willing to take the risk.

[alastaircoote]

It appears that Rust has recently added support for outputting Bitcode: rust-lang/rust#48896, in case that work provides any useful pointers for Kotlin Native.

[AxelDelmas]

Is there any news on this topic? We're also considering K/N but support for iOS bitcode is also a blocking point for us. Thanks

[ankushg]

Created a ticket on YouTrack for this since it seems like things are more frequently responded to by Jetbrains over there: https://youtrack.jetbrains.com/issue/KT-27147

[simonbengtsson]

Does this mean bitcode is supported now? 😲

https://github.com/JetBrains/kotlin-native/blob/master/FAQ.md#q-how-do-i-enable-bitcode-for-my-kotlin-framework

6cb4d0c af769d9

[olonho]

Not exactly bitcode, what we support is adding markers showing Apple tools that produced code is aware about bitcode and could be used with it. So please try and let us know about your results.

[KaiJSchaefer]

Have someone any experience with this compiler option "-Xembed-bitcode"? Does apple reject apps with this marker ?