1 files changed, 4 insertions, 0 deletions
diff --git a/compiler-rt/lib/fuzzer/FuzzerLoop.cpp b/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
index 4bc88365a0b..23fcb8a402d 100644
--- a/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
+++ b/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
@@ -38,6 +38,7 @@
 
 namespace fuzzer {
 static const size_t kMaxUnitSizeToPrint = 256;
+static const size_t kUpdateMutationWeightRuns = 10000;
 
 thread_local bool Fuzzer::IsMyThread;
 
@@ -554,6 +555,9 @@ static bool LooseMemeq(const uint8_t *A, const uint8_t *B, size_t Size) {
 
 void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
   TPC.RecordInitialStack();
+  if (Options.UseWeightedMutations &&
+      TotalNumberOfRuns % kUpdateMutationWeightRuns == 0)
+    MD.UpdateDistribution();
   TotalNumberOfRuns++;
   assert(InFuzzingThread());
   if (SMR.IsClient())