[llvm] [DebugInfo][RemoveDIs] Find types hidden in DbgRecords (PR #106547)

[Orlando Cazalet-Hyams via llvm-commits]

================
@@ -88,6 +88,17 @@ void TypeFinder::run(const Module &M, bool onlyNamed) {
         for (const auto &MD : MDForInst)
           incorporateMDNode(MD.second);
         MDForInst.clear();
+
+        // Incorporate types hiding in variable-location information.
+        for (const auto &Dbg : I.getDbgRecordRange()) {
+          // Pick out records that have Values.
+          if (Dbg.getRecordKind() != DbgRecord::Kind::ValueKind)
+            continue;
+          const DbgVariableRecord &DVI = static_cast<const DbgVariableRecord &>(Dbg);
+          for (Value *V : DVI.location_ops()) {
+            incorporateValue(V);
+          }
----------------
OCHyams wrote:

```suggestion
          if (const DbgVariableRecord*DVI = dyn_cast<DbgVariableRecord>(&Dbg) {
            for (Value *V : DVI->location_ops())
              incorporateValue(V);
             if (Value *Addr = DVI->getAddress(); Addr && DVI->isDbgAssign())
               incorperateValue(Addr);
          }
```

Better to use the dyn/isa casting rather than checking the subclass discriminator directly (`if (Dbg.getRecordKind() != DbgRecord::Kind::ValueKind)`)?

I think we also need to add dbg_assign address component values too (there's no operand iterator that includes that sadly).

I've incorporated both those fixes in the suggestion.

https://github.com/llvm/llvm-project/pull/106547