[llvm] [NewPM][CodeGen] add TargetPassConfig like API (PR #70906)

[Arthur Eubanks via llvm-commits]

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@@ -134,7 +167,19 @@ template <typename DerivedT> class CodeGenPassBuilder {
   }
 
   PassInstrumentationCallbacks *getPassInstrumentationCallbacks() const {
-    return PIC;
+    static PassInstrumentationCallbacks PseudoPIC;
+    return PIC ? PIC : &PseudoPIC;
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aeubanks wrote:

why is this necessary?

https://github.com/llvm/llvm-project/pull/70906