OptDiag: Allow constructing DiagnosticLocation from DISubprograms

This avoids creating a DILocation just to represent a line number,
since creating Metadata is expensive. Creating a DiagnosticLocation
directly is much cheaper.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295531 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed