To my surprise, lua.vm.js gzipped is about the same size (within 2K) as my Win32 Lua DLL build gzipped. The latter has the Microsoft C runtime statically linked, making the comparison more fair IIUC, since code built with Emscripten has to include a libc implementation.

This finding demonstrates that asm.js isn't significantly less efficient than LLVM bitcode or native code, even though it's text.