There's an interesting new open-source LLVM-using project called Emscripten. Emscripten allows JavaScript to be automatically generated from LLVM bit-code. In other words, you can take C/C++ code-bases and easily translate them into JavaScript.
Emscripten takes LLVM bitcode and from that turns it into JavaScript that can be executed from the web-browser. The LLVM bit-code can be generated from the Clang C/C++ compiler or any other LLVM front-end that ends up being lowered down into LLVM bit-code.
This translator doesn't work only for trivial projects, but large code-bases like Python, Bullet, and Poppler have been converted from their C/C++ code into working JavaScript using Emscripten. This project was brought up by Alon Zakai of Mozilla to
the LLVM developers' list.
Other code-bases that have been changed into JavaScript for demo purposes include Lua, FreeType, eSpeak text synthesis, a ray-tracing engine, Python, and Ruby.
For those interested in learning more about this neat LLVM project, visit
the GitHub project page.