[llvm] [BPF] Handle data-carrying enums (PR #155783)

[via llvm-commits]

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@@ -696,10 +710,14 @@ void BTFDebug::visitStructType(const DICompositeType *CTy, bool IsStruct,
   // Visit all struct members.
   int FieldNo = 0;
   for (const auto *Element : Elements) {
-    const auto Elem = cast<DIDerivedType>(Element);
-    visitTypeEntry(Elem);
-    processDeclAnnotations(Elem->getAnnotations(), TypeId, FieldNo);
-    FieldNo++;
+    if (const auto *Elem = dyn_cast<DIDerivedType>(Element)) {
+      visitTypeEntry(Elem);
+      processDeclAnnotations(Elem->getAnnotations(), TypeId, FieldNo);
+      FieldNo++;
+    } else if (const auto *Elem = dyn_cast<DICompositeType>(Element)) {
+      auto Tag = CTy->getTag();
+      visitStructType(Elem, Tag == dwarf::DW_TAG_structure_type, TypeId);
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eddyz87 wrote:

Also, maybe route the Elem via `visitTypeEntry`, extending it to support `DW_TAG_variant` / `DW_TAG_variant_part`?
So that processing remains more or less uniform.

https://github.com/llvm/llvm-project/pull/155783