Entity can now refer to declarations that are not visible outside the translation unit.
It is a wrapper of a pointer union, it's either a Decl* for declarations that don't
"cross" translation units, or an EntityImpl* which is associated with the specific "visible" Decl.
Included is a test case for handling fields across translation units.
llvm-svn: 76515
Its purpose is to provide the basic infrastructure for cross-translation-unit analysis like indexing, refactoring, etc.
Currently it is very "primitive" and with no type-names support. It can provide functionality like
"show me all references of this function from these translation units".
llvm-svn: 74802
Argyrios Kyrtzidis