[BOLT] Fix merge-fdata for memory events (#128108)

aaupov · web-flow · commit b01c3d6682d2 · 2026-01-05T20:21:32.000-08:00
Don't attempt to parse mispredictions for memory entries in LBR profile.

Test Plan: added merge-fdata-mem-prof.test
diff --git a/bolt/test/merge-fdata-bat-no-lbr.test b/bolt/test/merge-fdata-bat-no-lbr.test
@@ -8,13 +8,13 @@
 
 # CHECK: boltedcollection
 # CHECK: no_lbr
-# CHECK: main 2
+# CHECK: 1 main 2
 
 #--- a.fdata
 boltedcollection
 no_lbr
-main 1
+1 main 1
 #--- b.fdata
 boltedcollection
 no_lbr
-main 1
+1 main 1
diff --git a/bolt/test/merge-fdata-mem-prof.test b/bolt/test/merge-fdata-mem-prof.test
@@ -0,0 +1,17 @@
+## Check that merge-fdata tool correctly handles memory profile, emitting it
+## after branch profile.
+
+# REQUIRES: system-linux
+
+# RUN: split-file %s %t
+# RUN: merge-fdata %t/a.fdata %t/b.fdata -o %t/merged.fdata
+# RUN: FileCheck %s --input-file %t/merged.fdata
+
+# CHECK:      1 main 5 1 main 10 0 1
+# CHECK-NEXT: 4 Curl_cf_def_query c 4 Curl_cft_h1_proxy 68 3
+
+#--- a.fdata
+4 Curl_cf_def_query c 4 Curl_cft_h1_proxy 68 1
+4 Curl_cf_def_query c 4 Curl_cft_h1_proxy 68 2
+#--- b.fdata
+1 main 5 1 main 10 0 1
diff --git a/bolt/test/merge-fdata-mixed-bat-no-lbr.test b/bolt/test/merge-fdata-mixed-bat-no-lbr.test
@@ -10,7 +10,7 @@
 #--- a.fdata
 boltedcollection
 no_lbr
-main 1
+1 main 1
 #--- b.fdata
 no_lbr
-main 1
+1 main 1
diff --git a/bolt/test/merge-fdata-mixed-mode.test b/bolt/test/merge-fdata-mixed-mode.test
@@ -10,6 +10,6 @@
 
 #--- a.fdata
 no_lbr
-main 1
+1 main 1
 #--- b.fdata
-main 1
+1 main 1
diff --git a/bolt/test/merge-fdata-no-lbr-mode.test b/bolt/test/merge-fdata-no-lbr-mode.test
@@ -8,11 +8,11 @@
 # RUN: FileCheck %s --input-file %t/merged.fdata
 
 # CHECK: no_lbr
-# CHECK: main 2
+# CHECK: 1 main 2
 
 #--- a.fdata
 no_lbr
-main 1
+1 main 1
 #--- b.fdata
 no_lbr
-main 1
+1 main 1
diff --git a/bolt/tools/merge-fdata/merge-fdata.cpp b/bolt/tools/merge-fdata/merge-fdata.cpp
@@ -278,7 +278,10 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
     }
     CounterTy operator+(const CounterTy &O) { return *this += O; }
   };
-  typedef StringMap<CounterTy> ProfileTy;
+  struct ProfileTy {
+    StringMap<CounterTy> Branch;
+    StringMap<CounterTy> Memory;
+  };
 
   auto ParseProfile = [&](const std::string &Filename, auto &Profiles) {
     const llvm::thread::id tid = llvm::this_thread::get_id();
@@ -316,19 +319,23 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
     do {
       StringRef Line(FdataLine);
       CounterTy Count;
+      unsigned Type = 0;
+      if (Line.split(' ').first.getAsInteger(10, Type))
+        report_error(Filename, "Malformed / corrupted entry type");
+      bool IsBranchEntry = Type < 3;
       auto [Signature, ExecCount] = Line.rsplit(' ');
       if (ExecCount.getAsInteger(10, Count.Exec))
         report_error(Filename, "Malformed / corrupted execution count");
       // Only LBR profile has misprediction field
-      if (!NoLBRCollection.value_or(false)) {
+      if (!NoLBRCollection.value_or(false) && IsBranchEntry) {
         auto [SignatureLBR, MispredCount] = Signature.rsplit(' ');
         Signature = SignatureLBR;
         if (MispredCount.getAsInteger(10, Count.Mispred))
           report_error(Filename, "Malformed / corrupted misprediction count");
       }
 
-      Count += Profile->lookup(Signature);
-      Profile->insert_or_assign(Signature, Count);
+      auto &ProfileMap = IsBranchEntry ? Profile->Branch : Profile->Memory;
+      ProfileMap[Signature] += Count;
     } while (std::getline(FdataFile, FdataLine));
   };
 
@@ -344,22 +351,25 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
   Pool.wait();
 
   ProfileTy MergedProfile;
-  for (const auto &[Thread, Profile] : ParsedProfiles)
-    for (const auto &[Key, Value] : Profile) {
-      CounterTy Count = MergedProfile.lookup(Key) + Value;
-      MergedProfile.insert_or_assign(Key, Count);
-    }
+  for (const auto &[Thread, Profile] : ParsedProfiles) {
+    for (const auto &[Key, Value] : Profile.Branch)
+      MergedProfile.Branch[Key] += Value;
+    for (const auto &[Key, Value] : Profile.Memory)
+      MergedProfile.Memory[Key] += Value;
+  }
 
   if (BoltedCollection.value_or(false))
     output() << "boltedcollection\n";
   if (NoLBRCollection.value_or(false))
     output() << "no_lbr\n";
-  for (const auto &[Key, Value] : MergedProfile) {
+  for (const auto &[Key, Value] : MergedProfile.Branch) {
     output() << Key << " ";
     if (!NoLBRCollection.value_or(false))
       output() << Value.Mispred << " ";
     output() << Value.Exec << "\n";
   }
+  for (const auto &[Key, Value] : MergedProfile.Memory)
+    output() << Key << ' ' << Value.Exec << '\n';
 
   errs() << "Profile from " << Filenames.size() << " files merged.\n";
 }
