[clang] [CodeGen][CIR] Split out Backend Diags to utils, impl CIR error-attr (PR #225966)

[Andy Kaylor via cfe-commits]

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@@ -299,9 +272,7 @@ void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
   for (auto &F : getModule()->functions()) {
     if (const Decl *FD = Gen->GetDeclForMangledName(F.getName())) {
       auto Loc = FD->getASTContext().getFullLoc(FD->getLocation());
-      // TODO: use a fast content hash when available.
-      auto NameHash = llvm::hash_value(F.getName());
-      ManglingFullSourceLocs.push_back(std::make_pair(NameHash, Loc));
+      DiagConsumer.addFunctionSourceLocation(F.getName(), Loc);
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andykaylor wrote:

We don't call this on the CIR path. Should we?

https://github.com/llvm/llvm-project/pull/225966