[llvm-profdata] Add overlap command to compute similarity b/w two profile files

Add overlap functionality to llvm-profdata tool to compute the similarity
between two profile files.

Differential Revision: https://reviews.llvm.org/D60977

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359612 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ProfileData/InstrProfReader.cpp

@@ -900,3 +900,17 @@ Error IndexedInstrProfReader::readNextRecord(NamedInstrProfRecord &Record) {
   }
   return success();
 }
+
+void InstrProfReader::accumuateCounts(CountSumOrPercent &Sum, bool IsCS) {
+  uint64_t NumFuncs = 0;
+  for (const auto &Func : *this) {
+    if (isIRLevelProfile()) {
+      bool FuncIsCS = NamedInstrProfRecord::hasCSFlagInHash(Func.Hash);
+      if (FuncIsCS != IsCS)
+        continue;
+    }
+    Func.accumuateCounts(Sum);
+    ++NumFuncs;
+  }
+  Sum.NumEntries = NumFuncs;
+}