From: Kostya Serebryany <kcc@google.com>
Date: Tue, 27 Dec 2016 22:15:04 +0000 (+0000)
Subject: [libFuzzer] don't create large random mutations when given an empty seed
X-Git-Tag: android-x86-7.1-r4~22698
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=8f45dd30a790c71e7f230de4412338763b0cd92f;p=android-x86%2Fexternal-llvm.git

[libFuzzer] don't create large random mutations when given an empty seed

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290634 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Fuzzer/FuzzerMutate.cpp b/lib/Fuzzer/FuzzerMutate.cpp
index 80b7a5f961f..96a87b879d6 100644
--- a/lib/Fuzzer/FuzzerMutate.cpp
+++ b/lib/Fuzzer/FuzzerMutate.cpp
@@ -486,7 +486,7 @@ size_t MutationDispatcher::MutateImpl(uint8_t *Data, size_t Size,
                                       const std::vector<Mutator> &Mutators) {
   assert(MaxSize > 0);
   if (Size == 0) {
-    for (size_t i = 0; i < MaxSize; i++)
+    for (size_t i = 0; i < Min(size_t(4), MaxSize); i++)
       Data[i] = RandCh(Rand);
     if (Options.OnlyASCII)
       ToASCII(Data, MaxSize);