[BOLT] Enable merge branch profile with memory profile

[Jianghibo]

Allows merging the memory profiles with basic sampling profiles or LBR sampling profils.

Using std::map instead of StringMap to keep records in order: For profiles that mix branch and memory information, since llvm-bolt processes branch and memory information sequentially, it is essential to ensure that the data of these two types remains relatively independent.

[llvmbot]

@llvm/pr-subscribers-bolt

Author: Haibo Jiang (Jianghibo)

Changes

Allows merging the memory profiles with basic sampling profiles or LBR sampling profils.

Using std::map instead of StringMap to keep records in order: For profiles that mix branch and memory information, since llvm-bolt processes branch and memory information sequentially, it is essential to ensure that the data of these two types remains relatively independent.

---

Full diff: https://github.com/llvm/llvm-project/pull/174405.diff

2 Files Affected:

• (added) bolt/test/merge-fdata-mixed-branch-memory.test (+15)
• (modified) bolt/tools/merge-fdata/merge-fdata.cpp (+22-4)

diff --git a/bolt/test/merge-fdata-mixed-branch-memory.test b/bolt/test/merge-fdata-mixed-branch-memory.test
new file mode 100644
index 0000000000000..8ad3e3f8ac9dc
--- /dev/null
+++ b/bolt/test/merge-fdata-mixed-branch-memory.test
@@ -0,0 +1,15 @@
+## Check that merge-fdata correctly handles merging two fdata files with no_lbr/lbr sampling and memory sampling.
+
+# 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/merge.fdata
+#
+# CHECK: 1 main 0 1 main 2 0 1
+# CHECK: 4 main 10 4 othreSym 123 1
+
+#--- a.fdata
+1 main 0 1 main 2 0 1
+#--- b.fdata
+4 main 10 4 otherSym 123 1
diff --git a/bolt/tools/merge-fdata/merge-fdata.cpp b/bolt/tools/merge-fdata/merge-fdata.cpp
index f5b0251ea0331..1b94c67a53fda 100644
--- a/bolt/tools/merge-fdata/merge-fdata.cpp
+++ b/bolt/tools/merge-fdata/merge-fdata.cpp
@@ -263,6 +263,14 @@ bool isYAML(const StringRef Filename) {
   return false;
 }
 
+bool isBasicOrLBRItem(APInt SymbolValue) {
+  return SymbolValue.sge(0) && SymbolValue.sle(2);
+}
+
+bool isMemoryItem(APInt SymbolValue) {
+  return SymbolValue.sge(3) && SymbolValue.sle(5);
+}
+
 void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
   errs() << "Using legacy profile format.\n";
   std::optional<bool> BoltedCollection;
@@ -319,8 +327,12 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
       auto [Signature, ExecCount] = Line.rsplit(' ');
       if (ExecCount.getAsInteger(10, Count.Exec))
         report_error(Filename, "Malformed / corrupted execution count");
+
+      auto [Symbol, Record] = Signature.split(' ');
+      APInt SymbolValue;
+      Symbol.getAsInteger(10, SymbolValue);
       // Only LBR profile has misprediction field
-      if (!NoLBRCollection.value_or(false)) {
+      if (!NoLBRCollection.value_or(false) && isBasicOrLBRItem(SymbolValue)) {
         auto [SignatureLBR, MispredCount] = Signature.rsplit(' ');
         Signature = SignatureLBR;
         if (MispredCount.getAsInteger(10, Count.Mispred))
@@ -343,10 +355,13 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
     Pool.async(ParseProfile, std::cref(Filename), std::ref(ParsedProfiles));
   Pool.wait();
 
-  ProfileTy MergedProfile;
+  std::map<StringRef, CounterTy> MergedProfile;
   for (const auto &[Thread, Profile] : ParsedProfiles)
     for (const auto &[Key, Value] : Profile) {
-      CounterTy Count = MergedProfile.lookup(Key) + Value;
+      auto It = MergedProfile.find(Key);
+      CounterTy Count = It != MergedProfile.end() ? It->second + Value
+                                                  : Value;
+
       MergedProfile.insert_or_assign(Key, Count);
     }
 
@@ -356,7 +371,10 @@ void mergeLegacyProfiles(const SmallVectorImpl<std::string> &Filenames) {
     output() << "no_lbr\n";
   for (const auto &[Key, Value] : MergedProfile) {
     output() << Key << " ";
-    if (!NoLBRCollection.value_or(false))
+    auto [Symbol, Record] = key.split(' ');
+    APInt SymbolValue;
+    Symbol.getAsInteger(10, SymbolValue);
+    if (!NoLBRCollection.value_or(false) && isBasicOrLBRItem(SymbolValue))
       output() << Value.Mispred << " ";
     output() << Value.Exec << "\n";
   }

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[github-actions]

🐧 Linux x64 Test Results

• 608 tests passed
• 50 tests skipped

✅ The build succeeded and all tests passed.

[aaupov]

The issue should be addressed by #128108, please take a look

[Jianghibo]

The issue should be addressed by #128108, please take a look

Thanks, I will close this PR.

[Jianghibo]

The implementation already exists. see #128108