[llvm] [DebugInfo][NVPTX] Adding support for `inlined_at` debug directive in NVPTX backend (PR #170239)

[David Blaikie via llvm-commits]

https://github.com/dwblaikie commented:

I'm a bit confused by the implementation - at the start of the function, it scans for every inlined at location, then it checks if a given location has been found in that list and if it has, it emits it - but then removes these from the list?

It's possible for an inlinedAt location to appear more than once - it gets inlined, then some other code gets hoisted or sunk into the middle of the inlined location - what's meant to happen there?

I'd have expected the inlinedAt data to be on every .loc that is inlined - but maybe it's stateful? where you record the instruction that's at the start of an inlinedAt region, and the one that's at the end/just past the end? That seems a bit unfortunate/awkward, if it is the case... 

Maybe some small examples would be helpful?

https://github.com/llvm/llvm-project/pull/170239