llvm-project

bc216b05 - [Debugify] Improve reduction of debugify coverage build output (#150212)

[Debugify] Improve reduction of debugify coverage build output (#150212) In current DebugLoc coverage builds, the output for any reasonably large build can become very large if any missing DebugLocs are present; this happens because single errors in LLVM may result in many errors being reported in the output report. The main cause of this is that the empty locations attached to instructions may be propagated to other instructions in later passes, which will each be reported as new errors. This patch prevents this by adding an "unknown" annotation to instructions after reporting them once, ensuring that any other DebugLocs copied or derived from the original empty location will not be marked as new errors. As a separate but related change, this patch updates the report generation script to deduplicate results using the recorded stacktrace if they are available, instead of the pass+instruction combination. This reduces the size of the reduction, but makes the reduction highly reliable, as the stacktrace allows us to very precisely identify when two bugs have originated from the same place.