syntactically as a string, very similiar to what Chris did with MachO.
The parsing support and validation is not introduced yet.

llvm-svn: 78890

llvm-svn: 78666

2. Move section switch printing to MCSection virtual method which takes a
   TAI.  This eliminates textual formatting stuff from TLOF.
3. Eliminate SwitchToSectionDirective, getSectionFlagsAsString, and 
   TLOFELF::AtIsCommentChar.

llvm-svn: 78510

give the impls an object-file-specific name.  In the future
they can take different arguments etc.

llvm-svn: 78495

llvm-svn: 78060

llvm-svn: 78059

TAI.

llvm-svn: 77842