[lld] [PAC][lld] Do not emit AUTH relocs against undef weak non-preemptible symbols (PR #194636)

[Fangrui Song via llvm-commits]

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@@ -212,6 +214,19 @@ void AArch64::scanSectionImpl(InputSectionBase &sec, Relocs<RelTy> rels,
     // Relocation types that only need a RelExpr set `expr` and break out of
     // the switch to reach rs.process(). Types that need special handling
     // (fast-path helpers, TLS) call a handler and use `continue`.
+
+    auto handleTlsDescAuth = [&sym, &sec, type, offset,
+                              addend](RelExpr tlsdescExpr) {
+      if (sym.isUndefined() && !sym.isPreemptible) {
+        // Resolves statically to null. Handle in
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MaskRay wrote:

"// Resolves to addend."

https://github.com/llvm/llvm-project/pull/194636