linkGlobalVariableProto never returns null. Simplify the caller. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223424 91177308-0d34-0410-b5e6-96231b3b80d8
Make GetSVN.cmake do its VCS queries with native CMake code.
This lets the queries work on Windows as well as Linux.

This does mean make and cmake aren't using the same scripts to do the
queries (again), but at least GetSVN.cmake understands git and git-svn
as well as svn now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223425 91177308-0d34-0410-b5e6-96231b3b80d8
Add a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223427 91177308-0d34-0410-b5e6-96231b3b80d8
Cleanup: Calls to getDwarfRegNum() may actually fail, if there is
no DWARF register number mapping, or if the register was a virtual
register that was never materialized. Previously, we would just emit a
bogus location, after this patch we don't emit a location at all by
doing an early exit.

After my bugfix in r223401 today, this doesn't actually happen on any
target that I tested this with, but it's still preferable to make the
possibility of a failure explicit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223428 91177308-0d34-0410-b5e6-96231b3b80d8