[libFuzzer] add -shuffle flag

llvm-svn: 250603

1 files changed, 7 insertions, 5 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index a642bbbf5cb..ef71407d21c 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -137,11 +137,13 @@ void Fuzzer::ShuffleAndMinimize() {
     Printf("PreferSmall: %d\n", PreferSmall);
   PrintStats("READ  ", 0);
   std::vector<Unit> NewCorpus;
-  std::random_shuffle(Corpus.begin(), Corpus.end(), USF.GetRand());
-  if (PreferSmall)
-    std::stable_sort(
-        Corpus.begin(), Corpus.end(),
-        [](const Unit &A, const Unit &B) { return A.size() < B.size(); });
+  if (Options.ShuffleAtStartUp) {
+    std::random_shuffle(Corpus.begin(), Corpus.end(), USF.GetRand());
+    if (PreferSmall)
+      std::stable_sort(
+          Corpus.begin(), Corpus.end(),
+          [](const Unit &A, const Unit &B) { return A.size() < B.size(); });
+  }
   Unit &U = CurrentUnit;
   for (const auto &C : Corpus) {
     for (size_t First = 0; First < 1; First++) {