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[libFuzzer] extend the dictionary mutator to optionally overwrite data with the dict entry 

llvm-svn: 256900
This commit is contained in:
Kostya Serebryany 2016-01-06 02:13:04 +00:00
parent 52d3b67c1d
commit 80eb76abf4
1 changed files with 12 additions and 5 deletions
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17
llvm/lib/Fuzzer/FuzzerMutate.cpp
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@ -117,11 +117,18 @@ size_t MutationDispatcher::Mutate_AddWordFromDictionary(uint8_t *Data,
assert(!D.empty());
if (D.empty()) return 0;
const Unit &Word = D[Rand(D.size())];
if (Size + Word.size() > MaxSize) return 0;
size_t Idx = Rand(Size + 1);
memmove(Data + Idx + Word.size(), Data + Idx, Size - Idx);
memcpy(Data + Idx, Word.data(), Word.size());
return Size + Word.size();
if (Rand.RandBool()) { // Insert Word.
if (Size + Word.size() > MaxSize) return 0;
size_t Idx = Rand(Size + 1);
memmove(Data + Idx + Word.size(), Data + Idx, Size - Idx);
memcpy(Data + Idx, Word.data(), Word.size());
return Size + Word.size();
} else { // Overwrite some bytes with Word.
if (Word.size() > Size) return 0;
size_t Idx = Rand(Size - Word.size());
memcpy(Data + Idx, Word.data(), Word.size());
return Size;
}
}
size_t MutationDispatcher::Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size,