6 files changed, 5 insertions, 36 deletions
diff --git a/lib/fuzzer/FuzzerDriver.cpp b/lib/fuzzer/FuzzerDriver.cpp
index eb849fcd0..9375925b2 100644
--- a/lib/fuzzer/FuzzerDriver.cpp
+++ b/lib/fuzzer/FuzzerDriver.cpp
@@ -615,7 +615,6 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
   Options.PrintNewCovPcs = Flags.print_pcs;
   Options.PrintNewCovFuncs = Flags.print_funcs;
   Options.PrintFinalStats = Flags.print_final_stats;
-  Options.PrintMutationStats = Flags.print_mutation_stats;
   Options.PrintCorpusStats = Flags.print_corpus_stats;
   Options.PrintCoverage = Flags.print_coverage;
   Options.PrintUnstableStats = Flags.print_unstable_stats;
diff --git a/lib/fuzzer/FuzzerFlags.def b/lib/fuzzer/FuzzerFlags.def
index dc92758e4..e50b82ab7 100644
--- a/lib/fuzzer/FuzzerFlags.def
+++ b/lib/fuzzer/FuzzerFlags.def
@@ -155,4 +155,3 @@ FUZZER_DEPRECATED_FLAG(use_equivalence_server)
 FUZZER_FLAG_INT(analyze_dict, 0, "Experimental")
 FUZZER_DEPRECATED_FLAG(use_clang_coverage)
 FUZZER_FLAG_STRING(data_flow_trace, "Experimental: use the data flow trace")
-FUZZER_FLAG_INT(print_mutation_stats, 0, "Experimental")
diff --git a/lib/fuzzer/FuzzerLoop.cpp b/lib/fuzzer/FuzzerLoop.cpp
index 5497c1f61..ba61c15f0 100644
--- a/lib/fuzzer/FuzzerLoop.cpp
+++ b/lib/fuzzer/FuzzerLoop.cpp
@@ -358,8 +358,6 @@ void Fuzzer::PrintFinalStats() {
     TPC.DumpCoverage();
   if (Options.PrintCorpusStats)
     Corpus.PrintStats();
-  if (Options.PrintMutationStats)
-    MD.PrintMutationStats();
   if (!Options.PrintFinalStats)
     return;
   size_t ExecPerSec = execPerSec();
diff --git a/lib/fuzzer/FuzzerMutate.cpp b/lib/fuzzer/FuzzerMutate.cpp
index e260aa3fe..865e598fd 100644
--- a/lib/fuzzer/FuzzerMutate.cpp
+++ b/lib/fuzzer/FuzzerMutate.cpp
@@ -465,7 +465,6 @@ void MutationDispatcher::RecordSuccessfulMutationSequence() {
     if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
       PersistentAutoDictionary.push_back({DE->GetW(), 1});
   }
-  RecordUsefulMutations();
 }
 
 void MutationDispatcher::PrintRecommendedDictionary() {
@@ -487,7 +486,7 @@ void MutationDispatcher::PrintRecommendedDictionary() {
 void MutationDispatcher::PrintMutationSequence() {
   Printf("MS: %zd ", CurrentMutatorSequence.size());
   for (auto M : CurrentMutatorSequence)
-    Printf("%s-", M->Name);
+    Printf("%s-", M.Name);
   if (!CurrentDictionaryEntrySequence.empty()) {
     Printf(" DE: ");
     for (auto DE : CurrentDictionaryEntrySequence) {
@@ -515,13 +514,12 @@ size_t MutationDispatcher::MutateImpl(uint8_t *Data, size_t Size,
   // in which case they will return 0.
   // Try several times before returning un-mutated data.
   for (int Iter = 0; Iter < 100; Iter++) {
-    auto M = &Mutators[Rand(Mutators.size())];
-    size_t NewSize = (this->*(M->Fn))(Data, Size, MaxSize);
+    auto M = Mutators[Rand(Mutators.size())];
+    size_t NewSize = (this->*(M.Fn))(Data, Size, MaxSize);
     if (NewSize && NewSize <= MaxSize) {
       if (Options.OnlyASCII)
         ToASCII(Data, NewSize);
       CurrentMutatorSequence.push_back(M);
-      M->TotalCount++;
       return NewSize;
     }
   }
@@ -534,23 +532,4 @@ void MutationDispatcher::AddWordToManualDictionary(const Word &W) {
       {W, std::numeric_limits<size_t>::max()});
 }
 
-void MutationDispatcher::RecordUsefulMutations() {
-  for (auto M : CurrentMutatorSequence)
-    M->UsefulCount++;
-}
-
-void MutationDispatcher::PrintMutationStats() {
-  Printf("\nstat::mutation_usefulness:      ");
-  for (size_t i = 0; i < Mutators.size(); i++) {
-    double UsefulPercentage =
-        Mutators[i].TotalCount
-            ? (100.0 * Mutators[i].UsefulCount) / Mutators[i].TotalCount
-            : 0;
-    Printf("%.3f", UsefulPercentage);
-    if (i < Mutators.size() - 1)
-      Printf(",");
-  }
-  Printf("\n");
-}
-
 }  // namespace fuzzer
diff --git a/lib/fuzzer/FuzzerMutate.h b/lib/fuzzer/FuzzerMutate.h
index c0647ea78..996d756cd 100644
--- a/lib/fuzzer/FuzzerMutate.h
+++ b/lib/fuzzer/FuzzerMutate.h
@@ -86,16 +86,11 @@ public:
 
   Random &GetRand() { return Rand; }
 
-  void PrintMutationStats();
-
-  void RecordUsefulMutations();
-
 private:
+
   struct Mutator {
     size_t (MutationDispatcher::*Fn)(uint8_t *Data, size_t Size, size_t Max);
     const char *Name;
-    uint64_t UsefulCount;
-    uint64_t TotalCount;
   };
 
   size_t AddWordFromDictionary(Dictionary &D, uint8_t *Data, size_t Size,
@@ -133,8 +128,8 @@ private:
   // entries that led to successful discoveries in the past mutations.
   Dictionary PersistentAutoDictionary;
 
+  Vector<Mutator> CurrentMutatorSequence;
   Vector<DictionaryEntry *> CurrentDictionaryEntrySequence;
-  Vector<Mutator *> CurrentMutatorSequence;
 
   static const size_t kCmpDictionaryEntriesDequeSize = 16;
   DictionaryEntry CmpDictionaryEntriesDeque[kCmpDictionaryEntriesDequeSize];
diff --git a/lib/fuzzer/FuzzerOptions.h b/lib/fuzzer/FuzzerOptions.h
index daa9104f5..e32b7d59b 100644
--- a/lib/fuzzer/FuzzerOptions.h
+++ b/lib/fuzzer/FuzzerOptions.h
@@ -52,7 +52,6 @@ struct FuzzingOptions {
   bool PrintNewCovPcs = false;
   int PrintNewCovFuncs = 0;
   bool PrintFinalStats = false;
-  bool PrintMutationStats = false;
   bool PrintCorpusStats = false;
   bool PrintCoverage = false;
   bool PrintUnstableStats = false;