[lld] [lld-macho] Category Merger: add support for addrsig references (PR #90903)

[Ellis Hoag via llvm-commits]

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@@ -478,6 +482,8 @@ class ObjcCategoryMerger {
   std::vector<ConcatInputSection *> &allInputSections;
   // Map of base class Symbol to list of InfoInputCategory's for it
   DenseMap<const Symbol *, std::vector<InfoInputCategory>> categoryMap;
+  // Set for tracking InputSection erased via eraseISec
+  std::unordered_set<InputSection *> erasedIsecs;
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ellishg wrote:

It is usually preferred to use a vector and then sort + uniq elements, instead of using a set.
https://llvm.org/docs/ProgrammersManual.html#a-sorted-vector

Also, can we use `SmallVector` or `SmallPtrSet` here?

https://github.com/llvm/llvm-project/pull/90903