[lld] [lld-macho] Include branch extension thunks in linker map (PR #120496)

[via llvm-commits]

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@@ -220,7 +242,12 @@ void macho::writeMapFile() {
   os << "# Address\tSize    \tFile  Name\n";
   for (const OutputSegment *seg : outputSegments) {
     for (const OutputSection *osec : seg->getSections()) {
-      if (auto *concatOsec = dyn_cast<ConcatOutputSection>(osec)) {
+      const TextOutputSection *textOsec = dyn_cast<TextOutputSection>(osec);
+      if (textOsec && textOsec->getThunks().size()) {
+        auto inputsAndThunks =
+            mergeOrderedInputs(textOsec->inputs, textOsec->getThunks());
+        printIsecArrSyms(inputsAndThunks);
+      } else if (auto *concatOsec = dyn_cast<ConcatOutputSection>(osec)) {
         printIsecArrSyms(concatOsec->inputs);
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alx32 wrote:

I think we would want to add `classof()` to `TextOutputSection` regardless - I don't think we want to have `dyn_cast<TextOutputSection>` silently fail in the background with no reason. 

But I am not sure how `classof()` is relating to printing thunks - we need to identify the type of the output section regardless. 

About printing directly handling interleaving, this would be an option - I left a comment about it on  mergeOrderedInputs - but I'm wondering if it would be the clean approach here - especially if we can simplify `mergeOrderedInputs` into a `std::merge`. Do you prefer interleaved printing ? 

https://github.com/llvm/llvm-project/pull/120496