[lld] [llvm] [Symbolizer] Support for Missing Line Numbers. (PR #82240)

[David Blaikie via llvm-commits]

dwblaikie wrote:

OK then - I guess if we're doing this, I think it should be previous only ("as if line zero hadn't been emitted at all") - and the implementation should be tidied up/simplified a bit.

We shouldn't keep probing by the previous single address - the row returned by `findRowInSeq` should be decremented - looking at the previous row, until we either find a non-zero row, or reach `Seq.FirstRowIndex` - in the latter case, we should produce zero anyway, because there's no other address to produce reasonably (walking past the beginning of a sequence would give an arbitrary location in another .text section)?

https://github.com/llvm/llvm-project/pull/82240