From a44ebf4d065478d3042da45b9d0f7c3060da3b65 Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Thu, 19 Jan 2017 21:14:47 +0000
Subject: [PATCH] [libFuzzer] ensure that entries in PersistentAutoDictionary
 are not empty

llvm-svn: 292520
---
 llvm/lib/Fuzzer/FuzzerMutate.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/Fuzzer/FuzzerMutate.cpp b/llvm/lib/Fuzzer/FuzzerMutate.cpp
index f059264db8aa..9b019e9812fe 100644
--- a/llvm/lib/Fuzzer/FuzzerMutate.cpp
+++ b/llvm/lib/Fuzzer/FuzzerMutate.cpp
@@ -272,6 +272,7 @@ size_t MutationDispatcher::Mutate_AddWordFromTORC(
   default:
     assert(0);
   }
+  if (!DE.GetW().size()) return 0;
   Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
   if (!Size) return 0;
   DictionaryEntry &DERef =
@@ -462,6 +463,7 @@ void MutationDispatcher::RecordSuccessfulMutationSequence() {
   for (auto DE : CurrentDictionaryEntrySequence) {
     // PersistentAutoDictionary.AddWithSuccessCountOne(DE);
     DE->IncSuccessCount();
+    assert(DE->GetW().size());
     // Linear search is fine here as this happens seldom.
     if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
       PersistentAutoDictionary.push_back({DE->GetW(), 1});
@@ -476,6 +478,7 @@ void MutationDispatcher::PrintRecommendedDictionary() {
   if (V.empty()) return;
   Printf("###### Recommended dictionary. ######\n");
   for (auto &DE: V) {
+    assert(DE.GetW().size());
     Printf("\"");
     PrintASCII(DE.GetW(), "\"");
     Printf(" # Uses: %zd\n", DE.GetUseCount());