Convert some assert(0) to llvm_unreachable or fold an 'if' condition into the assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211254 91177308-0d34-0410-b5e6-96231b3b80d8
80-column fixups.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211255 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unnecessary include.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211256 91177308-0d34-0410-b5e6-96231b3b80d8
Move -dwarf-version to an MC level command line option so it's
used by all of the MC level tools and codegen. Fix up all uses
in the compiler to use this and set it on the context accordingly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211257 91177308-0d34-0410-b5e6-96231b3b80d8