[llvm] [SampleFDO] Stale profile call-graph matching (PR #95135)

[via llvm-commits]

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@@ -72,34 +99,54 @@ class SampleProfileMatcher {
   uint64_t MismatchedCallsiteSamples = 0;
   uint64_t RecoveredCallsiteSamples = 0;
 
+  // Profile call-graph matching statstics:
+  uint64_t NumRecoveredUnusedSamples = 0;
+  uint64_t NumRecoveredUnusedFunc = 0;
+
   // A dummy name for unknown indirect callee, used to differentiate from a
   // non-call instruction that also has an empty callee name.
   static constexpr const char *UnknownIndirectCallee =
       "unknown.indirect.callee";
 
 public:
-  SampleProfileMatcher(Module &M, SampleProfileReader &Reader,
-                       const PseudoProbeManager *ProbeManager,
-                       ThinOrFullLTOPhase LTOPhase)
-      : M(M), Reader(Reader), ProbeManager(ProbeManager), LTOPhase(LTOPhase){};
-  void runOnModule();
+  SampleProfileMatcher(
+      Module &M, SampleProfileReader &Reader,
+      const PseudoProbeManager *ProbeManager, ThinOrFullLTOPhase LTOPhase,
+      HashKeyMap<std::unordered_map, FunctionId, Function *> &SymMap,
+      std::shared_ptr<ProfileSymbolList> PSL)
+      : M(M), Reader(Reader), ProbeManager(ProbeManager), LTOPhase(LTOPhase),
+        SymbolMap(&SymMap), PSL(PSL) {};
+  void runOnModule(std::vector<Function *> &OrderedFuncList);
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WenleiHe wrote:

It's probably better not to have `runOnModule` not depend on a passed in ordered list. Given a module, the top-down order is deterministic. Depending on passed in order can be error prone as it's not guaranteed to be top-down. 

We can have `SampleProfileMatcher` ctor take CG, and build top down order from within `runOnModule`.

https://github.com/llvm/llvm-project/pull/95135