Dwarf Accelerator Tables

Hi All,

Some of you may have noticed a commit that added something called "Dwarf Accelerator Tables". The commit had a few of the salient points, but I thought I'd elaborate here and talk about what's going on with that.

Basically we've got the pubnames and pubtypes sections in dwarf that aren't particularly useful for debuggers. The code I just committed adds some new tables that allow better indexing for debuggers. LLDB is already equipped to deal with these tables in current ToT.

Going forward I'll be committing a few patches to fix issues as they come up and fixing up the type section information. Also coming tomorrow will be a longer spec with more detail and test cases are definitely forthcoming. We do plan to submit this for standardization with the dwarf community and welcome any feedback.