[llvm] r191792 - Debug Info: remove duplication of DIEs when a DIE is part of the type system

[Eric Christopher]

>
>>
>> I would like to revisit this (maybe revert this) later on when type units
>> are working.
>
>
> I'd rather revert this before type units (& then revisit this afterwards) as
> it may complicate the type unit work. I think the extra benefit (using
> direct ref_addr, rather than signatures) of this approach over type units
> may be implementable via an incremental improvement to type units.
>

FWIW I've been following along with the thread and agree here. David
is actively working on type units and we should have something here
shortly. Let's let that work proceed and revert this for now.

(and no, computing the hash isn't enough to matter time wise on anything)

-eric