dsymutil's Lockstep Algorithm

I was recently answering questions about dsymutil &rsquo;s multi-threading model and lockstep algorithm. I decided to write it down here for future reference. This article focuses on types and the .debug_info section. Background As a reminder, dsymutil is an optimizing DWARF linker. It only retains debug info for elements that appear in the final executable. It uses the One Definition Rule (ODR)…