[llvm] [CodeGen] Port mir-debugify to new pass manager (PR #193201)

[Matt Arsenault via llvm-commits]

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@@ -405,6 +405,19 @@ AnalysisKey NoOpLoopAnalysis::Key;
 
 namespace {
 
+bool applyMIRDebugify(DIBuilder &DIB, Function &F, ModuleAnalysisManager &AM) {
+  FunctionAnalysisManager &FAM =
+      AM.getResult<FunctionAnalysisManagerModuleProxy>(*F.getParent())
+          .getManager();
+
+  return applyDebugifyMetadataToMachineFunction(
+      DIB, F, [&](Function &Func) -> MachineFunction * {
+        MachineFunctionAnalysis::Result *MFA =
+            FAM.getCachedResult<MachineFunctionAnalysis>(Func);
+        return MFA ? &MFA->getMF() : nullptr;
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arsenm wrote:

Why is this getCachedResult? This shouldn't be able to fail? 

https://github.com/llvm/llvm-project/pull/193201