hierarchy with virtual methods and using llvm_unreachable to properly indicate
unreachable states which would otherwise leave variables uninitialized.

llvm-svn: 111803

cfe-dev, fixes an error compiling with MSVC.  Using a StringRef here doesn't
look safe in any case.

llvm-svn: 111513

llvm-svn: 111484

llvm-svn: 111480

For more information, see the accompanying clang patch.

llvm-svn: 111454

llvm-svn: 106834

The attribute class generation support is still somewhat limited.
See the accompanying clang commit for more details.

llvm-svn: 106174