llvm dev - Apr 2016 - RFC: Up front type information generation in clang

As an owner of several out-of-tree frontends, I'm mostly happy with this. 
It does mean I have to understand DWARF at a larger scope (fine with me, I know
people).  It also means I don't have to screw around in LLVM to add my
platform-specific tags for things like VMS descriptors and BLISS macros as those
get hoisted to my frontend(s).
> Migrate debug type information generation from the backends to the front
end.