[BOLT] Fix merge-fdata for memory events

[aaupov]

Don't attempt to parse mispredictions for memory entries in LBR profile.

Test Plan: added merge-fdata-mem-prof.test

[llvmbot]

@llvm/pr-subscribers-bolt

Author: Amir Ayupov (aaupov)

Changes

Don't attempt to parse mispredictions for memory entries in LBR profile.

Test Plan: added merge-fdata-mem-prof.test

---

Full diff: https://github.com/llvm/llvm-project/pull/128108.diff

2 Files Affected:

• (added) bolt/test/merge-fdata-mem-prof.test (+13)
• (modified) bolt/tools/merge-fdata/merge-fdata.cpp (+10-3)

diff --git a/bolt/test/merge-fdata-mem-prof.test b/bolt/test/merge-fdata-mem-prof.test
new file mode 100644
index 0000000000000..166d6028f7737
--- /dev/null
+++ b/bolt/test/merge-fdata-mem-prof.test
@@ -0,0 +1,13 @@
+## Check that merge-fdata tool correctly handles memory profile
+
+# REQUIRES: system-linux
+
+# RUN: split-file %s %t
+# RUN: merge-fdata %t/a.fdata -o %t/merged.fdata
+# RUN: FileCheck %s --input-file %t/merged.fdata
+
+# CHECK: 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
diff --git a/bolt/tools/merge-fdata/merge-fdata.cpp b/bolt/tools/merge-fdata/merge-fdata.cpp
index 74a5f8ca2d477..0cf5a03501728 100644
--- a/bolt/tools/merge-fdata/merge-fdata.cpp
+++ b/bolt/tools/merge-fdata/merge-fdata.cpp
@@ -316,11 +316,15 @@ 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)) {
+      // Only LBR profile has misprediction field, branch entries
+      if (!NoLBRCollection.value_or(false) && IsBranchEntry) {
         auto [SignatureLBR, MispredCount] = Signature.rsplit(' ');
         Signature = SignatureLBR;
         if (MispredCount.getAsInteger(10, Count.Mispred))
@@ -356,7 +360,10 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
     output() << "no_lbr\n";
   for (const auto &[Key, Value] : MergedProfile) {
     output() << Key << " ";
-    if (!NoLBRCollection.value_or(false))
+    unsigned Type = 0;
+    Key.split(' ').first.getAsInteger(10, Type);
+    bool IsBranchEntry = Type < 3;
+    if (!NoLBRCollection.value_or(false) && IsBranchEntry)
       output() << Value.Mispred << " ";
     output() << Value.Exec << "\n";
   }