I have been working on this too, and while I am not at all interested in embedding LLVM, the lack of calling conventions and lack of ability t make a direct jump is unfortunate.

My biggest pet peeve though is the inability to push unlikely stuff completely to the back of the program. I mean just put it away where nobody can see it. I also want to align code blocks to 1 bytes. Not 16 bytes. Not a single compiler lets me realign the instruction handlers in a way that compresses them down.

I also want to know what BOLT does that improves my interpreter by around 30%.