llvm-project

9c7b3047 - [WPD] Reduce ThinLTO link time by avoiding unnecessary summary analysis (#164046)

[WPD] Reduce ThinLTO link time by avoiding unnecessary summary analysis (#164046) We are scanning through every single definition of a vtable across all translation units which is unnecessary in most cases. If this is a local, we want to make sure there isn't another local with the same GUID due to it having the same relative path. However, we were always scanning through every single summary in all cases. We can now check the new HasLocal flag added in PR164647 ahead of the loop, instead of checking on every iteration. This cut down a large thin link by around 6%, which was over half the time it spent in WPD. Note that we previously took the last conforming vtable summary, and now we use the first. This caused a test difference in one somewhat contrived test for vtables in comdats.