Am I missing something about the terminology? This claims to be an "LLVM backend for Scala" which sounds wrong. Perhaps you want a backend that compiles LLVM AST to JVM bytecode. Or perhaps you want a Scala frontend that compiles Scala to LLVM AST. Unless they really intend to compile LLVM AST into Scala ... and then what?
What's front or back depends obviously on what your point of view is: Scala or LLVM.