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

[Arthur Eubanks via llvm-commits]

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@@ -448,6 +477,11 @@ template <typename T> void TextChangeReporter<T>::handleInitialIR(Any IR) {
   M->print(Out, nullptr);
 }
 
+template <typename T>
+void TextChangeReporter<T>::handleInitialMIR(const MachineFunction *IR) {
+  // For simplicity, don't print the initial MIR.
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aeubanks wrote:

add the reason that it's likely that the MIR doesn't initially exist

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