[PATCH] MS ABI: Give thunks linkonce_odr linkage

[Reid Kleckner]

It occurs to me that the linkage is still wrong for classes with thunks in anonymous namespaces.  It'd also be nice to have the thunks be discardable (i.e. linkonce_odr) in the common cases.

I think this is the right linkage computation:
- class has GVA_Internal linkage -> thunk is internal
- the thunk has a return adjustment -> thunk is weak_odr, to handle the evil corner case
- all other normal methods -> thunk is linkonce_odr

http://reviews.llvm.org/D3992