Refactor the construction of the DataLayout string on ARM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196843 91177308-0d34-0410-b5e6-96231b3b80d8
Rename CompileUnit->DwarfCompileUnit and TypeUnit->DwarfTypeUnit for
clarity. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196844 91177308-0d34-0410-b5e6-96231b3b80d8
Transforms: Don't create bad branch weights when folding a switch

This avoids creating branch weight metadata of length one when we fold
cases into the default of a switch instruction, which was triggering
an assert.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196845 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify further.

Thanks to Jim Grosbach for noticing it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196846 91177308-0d34-0410-b5e6-96231b3b80d8
80-col.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196848 91177308-0d34-0410-b5e6-96231b3b80d8
We never emit info into the macro info section, stop emitting an
empty one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196849 91177308-0d34-0410-b5e6-96231b3b80d8
Add comments documenting the ARM datalayout string.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196850 91177308-0d34-0410-b5e6-96231b3b80d8
Disable emitting DW_AT_GNU_ranges_base until we actually use it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196851 91177308-0d34-0410-b5e6-96231b3b80d8