[LLVMdev] Questions before moving the new debug info hierarchy into place

[Duncan P. N. Exon Smith]

> On 2015-Feb-20, at 11:34, Frédéric Riss <friss at apple.com> wrote:
> 
>> David also pointed out (in a previous thread about this) that
>> the frontend (or `DIBuilder`) might be the right location for
>> canonicalization.  Certainly, we couldn't canonicalize `..`
>> references without access to the filesystem (at least not on
>> POSIX platforms), but maybe we don't care about that anyway?
> 
> What I attempted to do in the past was exactly that, canonicalize ‘..’ in the paths 

On POSIX you need access to the filesystem to canonicalize
`..`  (if `./dir` is a symlink, then `./dir/../` does not
necessarily equal `./`), so any such canonicalization should
IMO be done outside of `MDFile`.  But yeah, we should revisit
this soon.

> (The lldb folks would have loved to be able to consider file identifiers as unique in the line table). 

This further requires resolving *all* symlinks in the path.
Certainly doable... but it's not just string manipulation.