I wish! Haha. No, it's a custom set of trampoline generators that handle the transition. I have one for Objective-C (where I can use the internal reflection tools to get function signatures; fails for variadic functions, so I wrote my own implementations of those, which live on the ARM side), one for C (I generated a function signature database for every header file on the system; otherwise, it shares the trampoline generator with Obj-C), and one for Swift (this is my WIP right now, where I'm generating a similar function database. By far the hardest part so far, if only because I'm so much less familiar with Swift).
There's also a native ARM build of libc++ and libc++abi, so that it doesn't have to cross the ARM<->Native boundary for C++ stuff, and a bunch of custom hooks on both sides.
I was using Unicorn (based on QEMU), but the license isn't conducive to a closed-source project. So I built my own emulator, which is released under a more friendly license: https://github.com/daeken/libmoonage
I was wondering how the code was that small, and then I saw the LLVM include ;) How are you planning on competing with people running binaries directly on their iOS devices?
For folks with existing setups they're happy with, my tool doesn't provide much value (aside from more easily working with existing dev tools in Xcode). But the ability to test real-world apps on any iOS version (mostly) and any device is pretty damn nice. Definitely a better testing experience than dealing with jailbreaks, wiping devices all the time, etc.
