[llvm] r203821 - MCDwarf: Refactor line table handling into a single data structure

[David Blaikie]

On Thu, Mar 13, 2014 at 11:09 AM, Rafael Espíndola
<rafael.espindola at gmail.com> wrote:
>> Also, might be a good basis to fold some of this handling down into
>> MCStreamers to avoid the special case of "One line table when doing asm
>> printing, line table per CU otherwise" by building it into the different
>> MCStreamer implementations.
>
> That is pr18716 btw.

Thanks for the pointer - Eric and I were chatting about this on the
way in this morning & I've some ideas about how this refactoring could
lay the foundation for resolving that issue - though I'm not sure I'll
get all the way to that in this particular refactoring effort. The
debug_line.dwo is my motivating use case for now.

(basically the idea is that once we've got line tables as a reusable
component it'd be nice to have each (compile or type) unit refer to
its line table directly (rather than going through DwarfDebug then to
MCStreamer and looking up by CUID each time..) - once that happens, we
could build a line table factory function into the MCStreamer - and
MCAsmStreamer would just keep returning the same line table while
MCObjectStreamer would return a new one each time (and we'd just keep
the type unit 'line' table in DwarfDebug directly))