[llvm] [llvm][dwarf][rfc][donotcommit] Enable print of ranges addresses from .debug_info.dwo (PR #65516)

[Alexander Yermolovich via llvm-commits]

ayermolo wrote:

> > > (be good to have a link to the original phab review to make it clear whatever context is being carried from there - I think I commented on the phab version of this)
> > > Yeah - currently if you dumped just the binary, it wouldn't dump associated dwo/dwp files - but we could make that happen & then it wouldn't need another input file argument (though might still need another flag to say whetwher to do this deep dumping, versus the current shallow behavior)
> > > That could also use the existing filter flags that only dump part of the input file to avoid dumping, say, the whole dwp file or all the dwo files.
> > > I don't feel /too/ strongly, but I do rather like the idea of relying on the existing paths/references in the format, rather than adding a new one.
> > 
> > 
> > Maybe I am missing something, but one downside going from main binary and using existing references (getNonSkeletonCU?), is that we will need to parse through all the CUs in the main binary to match DWO ID and figure out for which CU we need to get non-skeleton portion. In DWARF4 it's not part of the header either :( For pure split dwarf it's not that big of a deal, but for more complex build where there there are hundreds of megabytes of monolithic DWARF this can get annoying fast for the user.
> 
> Yeah, I was suggesting/thinking that the user could rely on `--lookup` or `--find`, but that might not always provide the features you want.
> 
> What's the use case you're interested in, I guess? If you didn't have Split DWARF, what would you be doing with the DWARF/trying to find out? (might be helpful to build features that aren't Split DWARF-specific, but work with Split DWARF too)
> 
> > Do you think I need to add anyone else to this review?
> 
> Don't think so?

This is 100% split dwarf specific. Main usage model is to be able to dump out .debug_info.dwo either full or specific dies (with usual optional parent/children flags), and see addresses and ranges. So to bring the functionality of monolithic dwarf to split-dwarf space.

https://github.com/llvm/llvm-project/pull/65516