The MSElang compiler will also compile the Free Pascal dialect used in MSEide+MSEgui. I am currently implementing that.
Because the parser is steered by a grammar script, it is easy to add the real MSElang grammar later.
MSElang produces LLVM bitcode which will be optimised and compiled to machine code by external LLVM programs.
Because MSElang does not link to LLVM libraries it is possible to use newer LLVM versions without hassle.
I recently switched from LLVM 3.5 to 3.7 and LLVM 3.7 could read the bitcode produced by MSElang for LLVM 3.5 without problems.
I currently read plenty of LLVM C++ code. OUCH! As Jonas writes, the worst possible C++ stile. It also doesn't look fast.
Unfortunately the new Free Pascal language elements remind me to that experience.
The internal in-memory representation of the program in MSElang can run in a MSElang runtime for scripting purpose directly without use of LLVM.