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

[via llvm-commits]

bd1976bris wrote:

The tests are much improved IMO. 

My high-level comment is that we don't need `llvm/test/tools/llvm-symbolizer/approximate-line-generated.s`. The comment near the top of that test states..

`## This test illustrates the usage of generated assembly by clang to produce the following line table:`

..but the point of the testing being added is to test `--skip-line-zero`. We need to produce test input with a valid line table to test `--skip-line-zero` and the tests should do so in the most readable manner, however, as long as the test input is correct it doesn't matter "how" it was produced. I see no benefit to Clang generating the line table assembly vs hand writing it.

I would move the test cases in `approximate-line-generated.s` into `approximate-line-handcrafted.s` (although some appear to be duplicates which can be dropped). I would also rename `approximate-line-handcrafted.s` to reflect that it is testing --skip-line-zero (e.g. `skip-line-zero.s)`.

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