[llvm] [CSSPGO] Compute and report profile matching recovered callsites and samples (PR #79090)

[via llvm-commits]

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@@ -478,20 +505,31 @@ class SampleProfileMatcher {
                      std::map<LineLocation, StringRef> &IRAnchors);
   void findProfileAnchors(
       const FunctionSamples &FS,
-      std::map<LineLocation, std::unordered_set<FunctionId>>
-          &ProfileAnchors);
-  void countMismatchedSamples(const FunctionSamples &FS);
-  void countProfileMismatches(
-      const Function &F, const FunctionSamples &FS,
-      const std::map<LineLocation, StringRef> &IRAnchors,
-      const std::map<LineLocation, std::unordered_set<FunctionId>>
-          &ProfileAnchors);
-  void countProfileCallsiteMismatches(
-      const FunctionSamples &FS,
-      const std::map<LineLocation, StringRef> &IRAnchors,
+      std::map<LineLocation, std::unordered_set<FunctionId>> &ProfileAnchors);
+  // Record the callsite match states for profile staleness report, the result
+  // is saved in FuncCallsiteMatchStates.
+  void recordCallsiteMatchStates(
+      const Function &F, const std::map<LineLocation, StringRef> &IRAnchors,
       const std::map<LineLocation, std::unordered_set<FunctionId>>
           &ProfileAnchors,
-      uint64_t &FuncMismatchedCallsites, uint64_t &FuncProfiledCallsites);
+      const LocToLocMap *IRToProfileLocationMap);
+
+  bool isMismatchState(const enum MatchState &State) {
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WenleiHe wrote:

Just to make sure I understand this, so this is because we compute hash on CFG (ignoring callee names). If a callee is renamed, even if checksum matches for the caller, we can have call site mismatch due to callee renaming (without caller CFG change). Is that the issue? 

I was hoping that we don't need to pay the cost of recording and computing stats if there is no mismatch. But if that's not possible, current change is fine. 

It begs another questions though... should checksum actually capture callee renaming? like if callee renamed, should caller's checksum change? 

https://github.com/llvm/llvm-project/pull/79090