I have to disagree with that. There are lots of languages whose purpose is to produce JS. For example, it would be very silly for CoffeeScript to use LLVM IR. It would end up reïmplementing all of the things that it shares with JS (that is, most of JS) with no conceivable benefit. Maybe if/when PNaCl is everywhere, it would make sense for it to do that, but even then it's a hard sell as long as four giant companies are competing their asses off to optimize JS.
But I do agree with you if the language doesn't correspond well with JS. In that case, it's probably better to target LLVM and then compile to JS via emscripten.
I have to disagree with that. There are lots of languages whose purpose is to produce JS. For example, it would be very silly for CoffeeScript to use LLVM IR. It would end up reïmplementing all of the things that it shares with JS (that is, most of JS) with no conceivable benefit. Maybe if/when PNaCl is everywhere, it would make sense for it to do that, but even then it's a hard sell as long as four giant companies are competing their asses off to optimize JS.
But I do agree with you if the language doesn't correspond well with JS. In that case, it's probably better to target LLVM and then compile to JS via emscripten.