[llvm] [CodeGen] Support start/stop in CodeGenPassBuilder (PR #70912)

[via llvm-commits]

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@@ -469,20 +486,36 @@ template <typename DerivedT> class CodeGenPassBuilder {
   const DerivedT &derived() const {
     return static_cast<const DerivedT &>(*this);
   }
+
+  void setStartStopPasses(const TargetPassConfig::StartStopInfo &Info) const;
+
+  Error verifyStartStop(const TargetPassConfig::StartStopInfo &Info) const;
+
+  mutable SmallVector<llvm::unique_function<bool(StringRef)>, 4>
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paperchalice wrote:

Currently IR passes and machine function passes are handled by different classes, and `-start/stop` options should support both IR and machine function passes, but it's OK to merge them into one class, because only `buildPipeline` creates instance of `AddIRPass` and `AddMachinePass`.

https://github.com/llvm/llvm-project/pull/70912