Revert "[libFuzzer] Mutation tracking and logging implemented"

This reverts r336597 due to bot breakage.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@336616 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerMutate.cpp b/FuzzerMutate.cpp
index ef059fc..865e598 100644
--- a/FuzzerMutate.cpp
+++ b/FuzzerMutate.cpp
@@ -58,10 +58,6 @@
   if (EF->LLVMFuzzerCustomCrossOver)
     Mutators.push_back(
         {&MutationDispatcher::Mutate_CustomCrossOver, "CustomCrossOver"});
-
-  // Initialize mutation statistic counters.
-  TotalMutations.resize(Mutators.size(), 0);
-  UsefulMutations.resize(Mutators.size(), 0);
 }
 
 static char RandCh(Random &Rand) {
@@ -265,9 +261,9 @@
     DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
   } break;
   case 3: if (Options.UseMemmem) {
-      auto X = TPC.MMT.Get(Rand.Rand());
-      DE = DictionaryEntry(X);
-    } break;
+    auto X = TPC.MMT.Get(Rand.Rand());
+    DE = DictionaryEntry(X);
+  } break;
   default:
     assert(0);
   }
@@ -435,18 +431,18 @@
   auto &U = MutateInPlaceHere;
   size_t NewSize = 0;
   switch(Rand(3)) {
-  case 0:
-    NewSize = CrossOver(Data, Size, O.data(), O.size(), U.data(), U.size());
-    break;
-  case 1:
-    NewSize = InsertPartOf(O.data(), O.size(), U.data(), U.size(), MaxSize);
-    if (!NewSize)
+    case 0:
+      NewSize = CrossOver(Data, Size, O.data(), O.size(), U.data(), U.size());
+      break;
+    case 1:
+      NewSize = InsertPartOf(O.data(), O.size(), U.data(), U.size(), MaxSize);
+      if (!NewSize)
+        NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
+      break;
+    case 2:
       NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
-    break;
-  case 2:
-    NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
-    break;
-  default: assert(0);
+      break;
+    default: assert(0);
   }
   assert(NewSize > 0 && "CrossOver returned empty unit");
   assert(NewSize <= MaxSize && "CrossOver returned overisized unit");
@@ -455,7 +451,7 @@
 }
 
 void MutationDispatcher::StartMutationSequence() {
-  CurrentMutatorIdxSequence.clear();
+  CurrentMutatorSequence.clear();
   CurrentDictionaryEntrySequence.clear();
 }
 
@@ -469,7 +465,6 @@
     if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
       PersistentAutoDictionary.push_back({DE->GetW(), 1});
   }
-  RecordUsefulMutations();
 }
 
 void MutationDispatcher::PrintRecommendedDictionary() {
@@ -489,9 +484,9 @@
 }
 
 void MutationDispatcher::PrintMutationSequence() {
-  Printf("MS: %zd ", CurrentMutatorIdxSequence.size());
-  for (auto M : CurrentMutatorIdxSequence)
-    Printf("%s-", Mutators[M].Name);
+  Printf("MS: %zd ", CurrentMutatorSequence.size());
+  for (auto M : CurrentMutatorSequence)
+    Printf("%s-", M.Name);
   if (!CurrentDictionaryEntrySequence.empty()) {
     Printf(" DE: ");
     for (auto DE : CurrentDictionaryEntrySequence) {
@@ -519,14 +514,12 @@
   // in which case they will return 0.
   // Try several times before returning un-mutated data.
   for (int Iter = 0; Iter < 100; Iter++) {
-    size_t MutatorIdx = Rand(Mutators.size());
-    auto M = Mutators[MutatorIdx];
+    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);
-      CurrentMutatorIdxSequence.push_back(MutatorIdx);
-      TotalMutations[MutatorIdx]++;
+      CurrentMutatorSequence.push_back(M);
       return NewSize;
     }
   }
@@ -539,23 +532,4 @@
       {W, std::numeric_limits<size_t>::max()});
 }
 
-void MutationDispatcher::RecordUsefulMutations() {
-  for (const size_t M : CurrentMutatorIdxSequence)
-    UsefulMutations[M]++;
-}
-
-void MutationDispatcher::PrintMutationStats() {
-  Printf("\nstat::mutation_usefulness:      ");
-  for (size_t i = 0; i < Mutators.size(); i++) {
-    double UsefulPercentage =
-        TotalMutations[i]
-            ? (100.0 * UsefulMutations[i]) / TotalMutations[i]
-            : 0;
-    Printf("%.3f", UsefulPercentage);
-    if (i < Mutators.size() - 1)
-      Printf(",");
-  }
-  Printf("\n");
-}
-
 }  // namespace fuzzer