[llvm] [SampleFDO] Stale profile call-graph matching (PR #92151)

[via llvm-commits]

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@@ -590,14 +618,308 @@ void SampleProfileMatcher::computeAndReportProfileStaleness() {
   }
 }
 
-void SampleProfileMatcher::runOnModule() {
-  ProfileConverter::flattenProfile(Reader.getProfiles(), FlattenedProfiles,
-                                   FunctionSamples::ProfileIsCS);
+void SampleProfileMatcher::findNewIRFunctions(
+    StringMap<Function *> &NewIRFunctions) {
+  // TODO: Support MD5 profile.
+  if (FunctionSamples::UseMD5)
+    return;
+  StringSet<> NamesInProfile;
+  if (auto NameTable = Reader.getNameTable()) {
+    for (auto Name : *NameTable)
+      NamesInProfile.insert(Name.stringRef());
+  }
+
   for (auto &F : M) {
-    if (skipProfileForFunction(F))
+    // Skip declarations, as even if the function can be matched, we have
+    // nothing to do with it.
+    if (F.isDeclaration())
       continue;
-    runOnFunction(F);
+
+    StringRef CanonFName = FunctionSamples::getCanonicalFnName(F.getName());
+    const auto *FS = getFlattenedSamplesFor(F);
+    if (FS)
+      continue;
+
+    // For extended binary, functions are fully inlined may not be loaded in the
+    // top-level profile, so check the NameTable which has the all symbol names
+    // in profile.
+    if (NamesInProfile.count(CanonFName))
+      continue;
+
+    // For extended binary, non-profiled function symbols are in the profile
+    // symbol list table.
+    if (PSL && PSL->contains(CanonFName))
+      continue;
+
+    LLVM_DEBUG(dbgs() << "Function " << CanonFName
+                      << " is not in profile or symbol list table.\n");
+    NewIRFunctions[CanonFName] = &F;
+  }
+}
+
+std::vector<Function *> *SampleProfileMatcher::findNewIRCallees(
+    Function &Func, const StringMap<Function *> &NewIRFunctions) {
+  auto R = FuncToNewCalleesMap.try_emplace(&Func, std::vector<Function *>());
+  std::vector<Function *> &IRCalleesToMatch = R.first->second;
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WenleiHe wrote:

This function by itself has nothing to do with matching, so the name `IRCalleesToMatch` can adds confusion. This is about finding new IR callees, so it should be named `NewIRCallees`. Whether the result is used to match something is outside of the scope of this function, and should not be used in the naming here.  

https://github.com/llvm/llvm-project/pull/92151