From 452879a466facf705d4f5b12617c2396b5689f35 Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Wed, 11 Oct 2017 01:44:26 +0000
Subject: [libFuzzer] experimental flag to tweak the corpus distribution. Seems
 to improve the situation dramatically on the png benchmark and make things
 worse on a number of micro-puzzles. Needs more A/B testing

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@315407 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/fuzzer/FuzzerLoop.cpp | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'lib/fuzzer/FuzzerLoop.cpp')

diff --git a/lib/fuzzer/FuzzerLoop.cpp b/lib/fuzzer/FuzzerLoop.cpp
index 4ccfe3f2a..c095fed12 100644
--- a/lib/fuzzer/FuzzerLoop.cpp
+++ b/lib/fuzzer/FuzzerLoop.cpp
@@ -396,6 +396,7 @@ bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
   size_t FoundUniqFeaturesOfII = 0;
   size_t NumUpdatesBefore = Corpus.NumFeatureUpdates();
   TPC.CollectFeatures([&](size_t Feature) {
+    Corpus.UpdateFeatureFrequency(Feature);
     if (Corpus.AddFeature(Feature, Size, Options.Shrink))
       UniqFeatureSetTmp.push_back(Feature);
     if (Options.ReduceInputs && II)
@@ -565,6 +566,8 @@ void Fuzzer::MutateAndTestOne() {
   MD.StartMutationSequence();
 
   auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
+  if (Options.UseFeatureFrequency)
+    Corpus.UpdateFeatureFrequencyScore(&II);
   const auto &U = II.U;
   memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
   assert(CurrentUnitData);
-- 
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