[llvm-branch-commits] [llvm] [NewPM] Introduce MFAnalysisGetter for a common analysis getter (PR #116166)

[Christudasan Devadasan via llvm-branch-commits]

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@@ -236,6 +238,82 @@ using MachineFunctionPassManager = PassManager<MachineFunction>;
 /// preserve.
 PreservedAnalyses getMachineFunctionPassPreservedAnalyses();
 
+/// For migrating to new pass manager
+/// Provides a common interface to fetch analyses instead of doing it twice in
+/// the *LegacyPass::runOnMachineFunction and NPM Pass::run.
+///
+/// NPM analyses must have the LegacyWrapper type to indicate which legacy
+/// analysis to run. Legacy wrapper analyses must have `getResult()` method.
+/// This can be added on a needs-to basis.
+///
+/// Outer analyses passes(Module or Function) can also be requested through
+/// `getAnalysis` or `getCachedAnalysis`.
+class MFAnalysisGetter {
+private:
+  Pass *LegacyPass = nullptr;
+  MachineFunctionAnalysisManager *MFAM = nullptr;
+
+  template <typename T>
+  using type_of_run =
+      typename function_traits<decltype(&T::run)>::template arg_t<0>;
+
+  template <typename T>
+  static constexpr bool IsFunctionAnalysis =
+      std::is_same_v<Function &, type_of_run<T>>;
+
+  template <typename T>
+  static constexpr bool IsModuleAnalysis =
+      std::is_same_v<Module &, type_of_run<T>>;
+
+public:
+  MFAnalysisGetter(Pass *LegacyPass) : LegacyPass(LegacyPass) {}
+  MFAnalysisGetter(MachineFunctionAnalysisManager *MFAM) : MFAM(MFAM) {}
+
+  /// Outer analyses requested from NPM will be cached results and can be null
+  template <typename AnalysisT>
+  typename AnalysisT::Result *getAnalysis(MachineFunction &MF) {
+    if (MFAM) {
+      // need a proxy to get the result for outer analyses
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cdevadas wrote:

Capitalize the first character.

https://github.com/llvm/llvm-project/pull/116166