[libFuzzer] add two flags, -tbm_depth and -tbm_width to control how the trace-based-mutations are applied

llvm-svn: 244712

1 files changed, 17 insertions, 6 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index b9c27e3f4a3..87ba0c0bbcd 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -81,9 +81,11 @@ void Fuzzer::PrintStats(const char *Where, size_t Cov, const char *End) {
   if (!Options.Verbosity) return;
   size_t Seconds = secondsSinceProcessStartUp();
   size_t ExecPerSec = (Seconds ? TotalNumberOfRuns / Seconds : 0);
-  Printf("#%zd\t%s cov: %zd bits: %zd units: %zd exec/s: %zd %s",
-         TotalNumberOfRuns, Where, Cov, TotalBits(), Corpus.size(), ExecPerSec,
-         End);
+  Printf("#%zd\t%s cov: %zd bits: %zd units: %zd exec/s: %zd",
+         TotalNumberOfRuns, Where, Cov, TotalBits(), Corpus.size(), ExecPerSec);
+  if (TotalNumberOfExecutedTraceBasedMutations)
+    Printf(" tbm: %zd", TotalNumberOfExecutedTraceBasedMutations);
+  Printf("%s", End);
 }
 
 void Fuzzer::RereadOutputCorpus() {
@@ -311,9 +313,18 @@ void Fuzzer::MutateAndTestOne(Unit *U) {
     U->resize(NewSize);
     RunOneAndUpdateCorpus(*U);
     size_t NumTraceBasedMutations = StopTraceRecording();
-    for (size_t j = 0; j < NumTraceBasedMutations; j++) {
-      ApplyTraceBasedMutation(j, U);
-      RunOneAndUpdateCorpus(*U);
+    size_t TBMWidth =
+        std::min((size_t)Options.TBMWidth, NumTraceBasedMutations);
+    size_t TBMDepth =
+        std::min((size_t)Options.TBMDepth, NumTraceBasedMutations);
+    Unit BackUp = *U;
+    for (size_t w = 0; w < TBMWidth; w++) {
+      *U = BackUp;
+      for (size_t d = 0; d < TBMDepth; d++) {
+        TotalNumberOfExecutedTraceBasedMutations++;
+        ApplyTraceBasedMutation(USF.GetRand()(NumTraceBasedMutations), U);
+        RunOneAndUpdateCorpus(*U);
+      }
     }
   }
 }