[llvm] [Instrumentation] Support MachineFunction in ChangeReporter (PR #80946)

[Arthur Eubanks via llvm-commits]

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@@ -448,6 +478,17 @@ template <typename T> void TextChangeReporter<T>::handleInitialIR(Any IR) {
   M->print(Out, nullptr);
 }
 
+template <typename T>
+void TextChangeReporter<T>::handleInitialMIR(const MachineFunction *IR) {
+  // Print all available machine functions.
+  const auto &MMI = IR->getMMI();
+  const auto &M = *MMI.getModule();
+  Out << "*** MIR Dump At Start ***\n";
+  for (const Function &F : M)
+    if (auto *MF = MMI.getMachineFunction(F))
+      MF->print(Out);
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aeubanks wrote:

that's a good point. I'm not sure if we should print something to tell the user that the machine function doesn't exist.

it is weird to print `MIR Dump At Start` and then not print anything if we don't have any MFs yet. perhaps we just don't print anything here if we don't have any MFs

https://github.com/llvm/llvm-project/pull/80946