Improve linkage of RTTI data structures. Introduce CodeGenModule::GetAddrOfRTTI which figures out the right linkage of the RTTI information for the given type and whether it should be defined or not. I will migrate clients over to GetAddrOfRTTI in subsequent commits (with tests).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@91098 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed