llvm-project

2f0902eb - [lld][MachO] Skip relinking -object_path_lto files that already match the cache (#237099)

[lld][MachO] Skip relinking -object_path_lto files that already match the cache (#237099) On an incremental ThinLTO link the object file from the previous link is usually already a hardlink to the same cache entry. Compare the two before touching anything, and take the modification time from the status that is already at hand instead of stat'ing the result again. The output path is also saved once up front and passed around as a StringRef instead of being copied for each use. On a 47k-module incremental ThinLTO link, saveOrHardlinkBuffer drops from 5% of link time to 0.3%. Also stop a link without -cache_path_lto from overwriting cache entries through hardlinks left in -object_path_lto.