Am 08.10.2018 um 01:34 schrieb Vanessa McHale:
The problem with an IR is that some languages would inevitably suffer - LLVM in particular was designed as a backend for a C compiler, and so it is not necessarily well-suited for lazy languages, immutable languages, etc. (not to mention self-modifying assembly and other such pathological beasts...) Actually LLVM is built for being adaptable to different kinds of languages. It does have a bias towards C-style languages, but you can adapt what doesn't fit your needs *and still keep the rest*.
The following was true a few years ago: When I asked, the LLVM IR was intentionally not specified to be reusable across languages, so that different compiler toolchain could adapt the IR to whatever needs their language or backend infrastructure needed. Garbage collection is one area where you have to do a lot of work. There are some primitive instructions that support it, but the semantics is vague and doesn't cover all kinds of write barriers. You'll have to roll your own IR extensions - or maybe I didn't understand the primitives well enough to see how much they cover. Anyway, LLVM does not come with a GC implementation. OTOH, it does not prevent you from doing a GC. In particular, you're free to avoid C-style pointers, so you have the full range of GC algorithms available. Laziness? No problem. If you do tagless/spineless, you'll code the evaluation machine anyway. Just add an IR instructions that calls the interpreter. Immutability? No problem - actually nowhere a problem. Immutability happens at the language level, at the IR level it is pretty irrelevant because compilers try to replace object copying by in-place modification wherever possible, anyway. Self-modifying assembly? No IR really supports that. Mostly it's backends that generate self-modifying code from IR instructions for specific backends. TL;DR: For its generality, LLVM IR is better suited to languages with specific needs in the backend than anything else that I have seen (which means C runtimes, various VM proofs of concept which don't really count, and JVM - in particular I don't know how .net compares). Regards, Jo