Remove duplicate copy of InstrItineraryData from the TargetMachine,
it's already on the subtarget.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210619 91177308-0d34-0410-b5e6-96231b3b80d8
Use an enum class.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210620 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: refactor DwarfException

DwarfException served as a base class for exception handling directive emission.
However, this is also used by other exception models (e.g. Win64EH).  Rename
this class to EHStreamer and split it out of DwarfException.h.  NFC.

Use the opportunity to fix up some of the documentation comments to match
current LLVM style.  Also rename some functions to conform better with current
LLVM coding style.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210622 91177308-0d34-0410-b5e6-96231b3b80d8
Use an enum class.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210623 91177308-0d34-0410-b5e6-96231b3b80d8