Return a DIDescriptor from CGDebugInfo::getDeclarationOrDefinition...

... instead of a DIScope that might wrap something that's not actually
a DIScope (eg. a DIGlobalVariable);

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221481 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen, Itanium: Properly dllimport RTTI data

We would blindly assume that RTTI data should have the same linkage as
the vtable because we didn't think the RTTI data was external.  This
oversight stemmed because we didn't take dllimport into account.

This fixes PR21512.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221511 91177308-0d34-0410-b5e6-96231b3b80d8
Improve comments in vtordisp tests: fix a typo, add a bit more clarity

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221524 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r221404 which caused lldb to not display
vararg expressions.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@221533 91177308-0d34-0410-b5e6-96231b3b80d8