diff options
| author | Dan Liew <dan@su-root.co.uk> | 2018-04-24 06:31:09 +0000 |
|---|---|---|
| committer | Dan Liew <dan@su-root.co.uk> | 2018-04-24 06:31:09 +0000 |
| commit | a97c9c4c7b68718987d90c9e483be0afa65bea1f (patch) | |
| tree | 1d2fe2d69a3fa897b760272f645aa822ee60e88b /lib/fuzzer/FuzzerMutate.cpp | |
| parent | 751fac1ff7dbff433b91becefe86c7b37b825607 (diff) | |
[LibFuzzer] Tweak `MutationDispatcher::Mutate_CopyPart` mutation.
It doesn't make sense to non-deterministically choose between
`CopyPart(..)` and `InsertPart(..)` when it is known that
`InsertPart(..)` will fail.
This upstream's a change from JFS solver's fork of LibFuzzer.
Differential Revision: https://reviews.llvm.org/D45693
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@330687 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/fuzzer/FuzzerMutate.cpp')
| -rw-r--r-- | lib/fuzzer/FuzzerMutate.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/fuzzer/FuzzerMutate.cpp b/lib/fuzzer/FuzzerMutate.cpp index e0e457852..865e598fd 100644 --- a/lib/fuzzer/FuzzerMutate.cpp +++ b/lib/fuzzer/FuzzerMutate.cpp @@ -339,7 +339,9 @@ size_t MutationDispatcher::InsertPartOf(const uint8_t *From, size_t FromSize, size_t MutationDispatcher::Mutate_CopyPart(uint8_t *Data, size_t Size, size_t MaxSize) { if (Size > MaxSize || Size == 0) return 0; - if (Rand.RandBool()) + // If Size == MaxSize, `InsertPartOf(...)` will + // fail so there's no point using it in this case. + if (Size == MaxSize || Rand.RandBool()) return CopyPartOf(Data, Size, Data, Size); else return InsertPartOf(Data, Size, Data, Size, MaxSize); |