[llvm-branch-commits] [NFCI][ELF][AArch64][PAC] Teach addRelativeReloc to emit R_AARCH64_AUTH_RELATIVE (PR #171180)

[Peter Smith via llvm-branch-commits]

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@@ -704,8 +704,10 @@ static void addRelativeReloc(Ctx &ctx, InputSectionBase &isec,
                              uint64_t offsetInSec, Symbol &sym, int64_t addend,
                              RelExpr expr, RelType type) {
   Partition &part = isec.getPartition(ctx);
+  bool isAArch64Auth =
+      ctx.arg.emachine == EM_AARCH64 && type == R_AARCH64_AUTH_ABS64;
 
-  if (sym.isTagged()) {
+  if (sym.isTagged() && !isAArch64Auth) {
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smithp35 wrote:

When both MTE and PAC are enabled the amount of bits avaible to PAC is reduced so they don't overlap with the bits used for MTE. They can be used together, although fewer bits available to PAC makes it statistically weaker.

https://github.com/llvm/llvm-project/pull/171180