Decl to Entity conversion

Hi all,
Can any one tell me how can i convert the clang::Decl to clang::idx::Entity?
Is clang::idx::Entity is useful to find the functions from different translation unit?


To do cross-TU referencing the optimal thing would probably be USRs

They seem coupled to libclang though, so I don't know how useful they
are when you want to use them from a clang plugin... Others may be
able to give context here.