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

[via llvm-commits]

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@@ -2443,53 +2372,222 @@ void SampleProfileMatcher::runOnFunction(const Function &F) {
   std::map<LineLocation, std::unordered_set<FunctionId>> ProfileAnchors;
   findProfileAnchors(*FSFlattened, ProfileAnchors);
 
-  // Detect profile mismatch for profile staleness metrics report.
-  // Skip reporting the metrics for imported functions.
-  if (!GlobalValue::isAvailableExternallyLinkage(F.getLinkage()) &&
-      (ReportProfileStaleness || PersistProfileStaleness)) {
-    // Use top-level nested FS for counting profile mismatch metrics since
-    // currently once a callsite is mismatched, all its children profiles are
-    // dropped.
-    if (const auto *FS = Reader.getSamplesFor(F))
-      countProfileMismatches(F, *FS, IRAnchors, ProfileAnchors);
-  }
+  // Compute the callsite match states for profile staleness report.
+  if (ReportProfileStaleness || PersistProfileStaleness)
+    computeCallsiteMatchStates(F, IRAnchors, ProfileAnchors, LocToLocMap());
 
   // Run profile matching for checksum mismatched profile, currently only
   // support for pseudo-probe.
   if (SalvageStaleProfile && FunctionSamples::ProfileIsProbeBased &&
       !ProbeManager->profileIsValid(F, *FSFlattened)) {
     // The matching result will be saved to IRToProfileLocationMap, create a new
     // map for each function.
+    auto &IRToProfileLocationMap = getIRToProfileLocationMap(F);
     runStaleProfileMatching(F, IRAnchors, ProfileAnchors,
-                            getIRToProfileLocationMap(F));
+                            IRToProfileLocationMap);
+    // Find and update callsite match states after matching.
+    if ((ReportProfileStaleness || PersistProfileStaleness) &&
+        !IRToProfileLocationMap.empty())
+      computeCallsiteMatchStates(F, IRAnchors, ProfileAnchors,
+                                 IRToProfileLocationMap);
   }
 }
 
-void SampleProfileMatcher::runOnModule() {
-  ProfileConverter::flattenProfile(Reader.getProfiles(), FlattenedProfiles,
-                                   FunctionSamples::ProfileIsCS);
-  for (auto &F : M) {
-    if (F.isDeclaration() || !F.hasFnAttribute("use-sample-profile"))
+void SampleProfileMatcher::computeCallsiteMatchStates(
+    const Function &F, const std::map<LineLocation, StringRef> &IRAnchors,
+    const std::map<LineLocation, std::unordered_set<FunctionId>>
+        &ProfileAnchors,
+    const LocToLocMap &IRToProfileLocationMap) {
+  // Use the matching result to determine if it's in post-match phrase.
+  bool IsPostMatch = !IRToProfileLocationMap.empty();
+  auto &MismatchedCallsites =
+      FuncCallsiteMatchStates[FunctionSamples::getCanonicalFnName(F.getName())];
+
+  auto MapIRLocToProfileLoc = [&](const LineLocation &IRLoc) {
+    const auto &ProfileLoc = IRToProfileLocationMap.find(IRLoc);
+    if (ProfileLoc != IRToProfileLocationMap.end())
+      return ProfileLoc->second;
+    else
+      return IRLoc;
+  };
+
+  std::set<LineLocation> MatchedCallsites;
+  for (const auto &I : IRAnchors) {
+    // In post-match, use the matching result to remap the current IR callsite.
+    const auto &Loc = MapIRLocToProfileLoc(I.first);
+    const auto &IRCalleeName = I.second;
+    const auto &It = ProfileAnchors.find(Loc);
+    if (It == ProfileAnchors.end())
       continue;
-    runOnFunction(F);
+    const auto &Callees = It->second;
+
+    // Since indirect call does not have CalleeName, check conservatively if
+    // callsite in the profile is a callsite location. This is to reduce num of
+    // false positive since otherwise all the indirect call samples will be
+    // reported as mismatching.
+    if (IRCalleeName == SampleProfileMatcher::UnknownIndirectCallee)
+      MatchedCallsites.insert(Loc);
+    // TODO : Ideally, we should ensure it's a direct callsite location(Callees
+    // size is 1). However, there may be a bug for profile merge(like ODR
+    // violation) that causes the callees size to be more than 1. After we fix
+    // the bug, we can remove this check.
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WenleiHe wrote:

Have you found out why? This particular change/workaround seems unrelated to the main purpose of this patch.  How about let's either 1) root cause and fix this or 2) not change it, not adding the workaround here.

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