[llvm] [CloneModule] Clone undefined ifuncs (PR #197353)

[Matt Arsenault via llvm-commits]

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@@ -117,6 +117,18 @@ std::unique_ptr<Module> llvm::CloneModule(
 
   for (const GlobalIFunc &I : M.ifuncs()) {
     // Defer setting the resolver function until after functions are cloned.
+    if (!ShouldCloneDefinition(&I)) {
+      // An ifunc also cannot act as an external reference, so we need to create
+      // a function depending on the value type.
+      GlobalValue *GV;
+      assert(I.getValueType()->isFunctionTy() &&
+             "IFunc resolver must be function type!");
+      GV = Function::Create(cast<FunctionType>(I.getValueType()),
+                            GlobalValue::ExternalLinkage, I.getAddressSpace(),
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arsenm wrote:

Should this preserve the linkage of the original value?

https://github.com/llvm/llvm-project/pull/197353