[llvm] [CFI/MergeFunctions] Modify MergeFunctions to propagate type information (PR #68628)

[Oskar Wirga via llvm-commits]

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@@ -740,6 +740,10 @@ void MergeFunctions::writeThunk(Function *F, Function *G) {
   } else {
     NewG->copyAttributesFrom(G);
     NewG->takeName(G);
+    // Ensure CFI type metadata is propagated to the new function.
+    if (MDNode *TypeMD = G->getMetadata("type")) {
+      NewG->setMetadata("type", TypeMD);
+    }
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oskarwirga wrote:

I have created a helper function in case others identify additional metadata that should be copied over. 

https://github.com/llvm/llvm-project/pull/68628