[libFuzzer] Mutation tracking and logging implemented.

Summary:
Code now exists to track number of mutations that are used in fuzzing in total
and ones that produce new coverage. The stats are currently being dumped to the
command line.

Patch by Kodé Williams (@kodewilliams).

Reviewers: metzman, Dor1s, morehouse, kcc

Reviewed By: Dor1s, morehouse, kcc

Subscribers: delcypher, kubamracek, kcc, morehouse, llvm-commits, #sanitizers, mgorny

Differential Revision: https://reviews.llvm.org/D48054

llvm-svn: 337194

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler-rt/lib/fuzzer/FuzzerOptions.h b/compiler-rt/lib/fuzzer/FuzzerOptions.h
index e32b7d59b85..daa9104f5c5 100644
--- a/compiler-rt/lib/fuzzer/FuzzerOptions.h
+++ b/compiler-rt/lib/fuzzer/FuzzerOptions.h
@@ -52,6 +52,7 @@ struct FuzzingOptions {
   bool PrintNewCovPcs = false;
   int PrintNewCovFuncs = 0;
   bool PrintFinalStats = false;
+  bool PrintMutationStats = false;
   bool PrintCorpusStats = false;
   bool PrintCoverage = false;
   bool PrintUnstableStats = false;