disallow !dbg and !prof metadata on ifuncs

Author: Wael Yehia

llvm/lib/IR/Verifier.cpp

@@ -999,6 +999,16 @@ void Verifier::visitGlobalAlias(const GlobalAlias &GA) {
 void Verifier::visitGlobalIFunc(const GlobalIFunc &GI) {
   visitGlobalValue(GI);
 
+  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
+  GI.getAllMetadata(MDs);
+  for (const auto &I : MDs) {
+    CheckDI(I.first != LLVMContext::MD_dbg,
+            "an ifunc may not have a !dbg attachment", &GI);
+    Check(I.first != LLVMContext::MD_prof,
+          "an ifunc may not have a !prof attachment", &GI);
+    visitMDNode(*I.second, AreDebugLocsAllowed::No);
+  }
+
   Check(GlobalIFunc::isValidLinkage(GI.getLinkage()),
         "IFunc should have private, internal, linkonce, weak, linkonce_odr, "
         "weak_odr, or external linkage!",