What are the details of DolphiniOS’s challenges with Apple’s new App Store policy changes regarding JIT?

Apple’s decision to permit game emulators on the App Store has sparked a range of responses. The Delta app saw a surge in popularity, but DolphiniOS was unable to gain traction due to Apple’s limitations on Just-in-Time (JIT) compilation.

The JIT Conundrum

DolphiniOS elaborated in a recent blog post that Apple’s reluctance to allow applications using JIT is the primary reason why the emulator has not made it to the App Store. This technical barrier is due to the different CPU architectures of the GameCube/Wii (PowerPC-based) and modern Apple devices (ARM-based).

What is JIT?

JIT or Just-in-Time compilation is the method used by Dolphin to translate PowerPC code from GameCube and Wii games into ARM code compatible with Apple devices. Thanks to this translation, games run smoothly on iPhone. Unfortunately, Apple’s iOS guidelines generally prohibit the use of JIT recompilers, with limited exceptions such as Safari and some European web browsers, reports 9to5mac.

Apple’s security concerns

Apple’s denial of DolphiniOS’s JIT request likely focuses on security concerns. While the exact reasons remain undisclosed, Apple’s cautious approach to JITs, as evidenced by the limitations of their JavaScript JITs in alternative European web browsers, hints at potential security risks.

Performance issues without JIT

While DolphiniOS can technically use an “interpreter” instead of a JIT, performance takes a significant hit. Tests on the iPhone 15 Pro Max revealed nearly unplayable playability, making this option impractical for App Store submissions due to likely user complaints and potential rejection from Apple’s App Review.

The future of DolphiniOS in the App Store

Despite the challenges, DolphiniOS developers express their willingness to cooperate with the Dolphin Emulator project to possibly release an official version on the App Store. However, this effort is dependent on checking Apple’s JIT limitations.

Although Apple’s policy change has opened the doors for some emulation apps, DolphiniOS still faces obstacles due to technical limitations. Unless Apple reconsiders its stance on JIT, it looks like DolphiniOS will be left out of the App Store ecosystem.