[llvm] [RemoveDIs][DebugInfo] Verifier and printing fixes for DPLabel (PR #83242)

[Paul T Robinson via llvm-commits]

pogo59 wrote:

> Is it possible to report this as an error instead of crashing?

I think so, but it would have to happen during the module loading stage of LTO. Currently the loader assumes that if it sees a second record with the same name, it's a duplicate and can be thrown away. ODR detection would instead need to do a deeper comparison to check whether it was a false duplicate.

IIRC @adrian-prantl pushed back on this the first time we ran into it, due to the increased expense of the checking for duplicates (which are likely to be common in LTO). I don't think we ever tried to measure the cost though. If it's high, we could possibly put it under an off-by-default option.

https://github.com/llvm/llvm-project/pull/83242