[Houshalter]

NaCL also needs those things because it has to compile it's bytecode to machine code on multiple architectures. It's no different than webasm, just a different bytecode. A big advantage of webasm is that it's integrated into the existing javascript VM, that has already been sandboxed and battle hardened.

[eridius]

I believe that's PNaCl. NaCl just handles already-compiled machine code. But of course NaCl isn't portable, which is why PNaCl exists.