llvm-project

076226f3 - [ELF] Separate relative and non-relative dynamic relocations (#187959)

[ELF] Separate relative and non-relative dynamic relocations (#187959) Previously, the flow was: 1. Parallel scan adds relative relocs to per-thread `relocsVec` 2. `mergeRels()` copies all into `relocs` 3. `partitionRels()` uses `stable_partition` to separate Now, relative relocs are routed at `addReloc` time by checking `reloc.type == relativeRel`. In `mergeRels`, sharded entries are classified through the same `addReloc` path rather than blindly appended. `relocsVec` may contain non-relative entries like `R_AARCH64_AUTH_RELATIVE`. This eliminates the `stable_partition` on the full relocation vector (543K entries for clang) and avoids copying relative relocations into `relocs` only to move them out again. Linking an x86_64 release+assertions build of clang is 1.04x as fast. `numRelativeRelocs` caches `relativeRelocs.size()` at `finalizeContents` time for `DT_RELACOUNT`. Using a live `relativeRelocs.size()` would cause `DynamicSection::writeTo` to emit an extra entry when thunks add relocs after `.dynamic` is sized, overflowing into adjacent sections. Tested by ppc64-long-branch-rel14.s.