Yes, there are demos of such things. For example, these two: http://kripken.github.io/clangor/demo.html http://kripken.github.io/clangor/demo.html http://krip

Yes, there are demos of such things. For example, these two: http://kripken.github.io/clangor/demo.html http://kripken.github.io/clangor/demo.html http://kripken.github.io/llvm.js/demo.html http://kripken.github.io/llvm.js/demo.html A bit old by now, but the first compiles C++ into LLVM IR, the second LLVM IR into JS and runs it. All of that happens clientside.