commit ad05ee0512119034e8c8e597dfe4959f97892b21
author Kostya Serebryany <kcc@google.com> Fri Dec 01 19:18:38 2017
committer Kostya Serebryany <kcc@google.com> Fri Dec 01 19:18:38 2017
tree 3a67ebc00819f6cc7a8d083ccb655a7e432c7970
parent 5cd0f44abc8008075522469f67cfb1bd04157220

[libFuzzer] add an experimental search heuristic flag -reduce_depth

llvm-svn: 319571

compiler-rt/lib/fuzzer/FuzzerLoop.cpp

diff --git a/compiler-rt/lib/fuzzer/FuzzerLoop.cpp b/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
index 81e609e..51d37c3 100644
--- a/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
+++ b/compiler-rt/lib/fuzzer/FuzzerLoop.cpp
@@ -433,7 +433,7 @@
 }
 
 bool Fuzzer::RunOne(const uint8_t *Data, size_t Size, bool MayDeleteFile,
-                    InputInfo *II) {
+                    InputInfo *II, bool *FoundUniqFeatures) {
   if (!Size)
     return false;
 
@@ -451,6 +451,8 @@
                              II->UniqFeatureSet.end(), Feature))
         FoundUniqFeaturesOfII++;
   });
+  if (FoundUniqFeatures)
+    *FoundUniqFeatures = FoundUniqFeaturesOfII;
   PrintPulseAndReportSlowInput(Data, Size);
   size_t NumNewFeatures = Corpus.NumFeatureUpdates() - NumUpdatesBefore;
   if (NumNewFeatures) {
@@ -642,11 +644,18 @@
     Size = NewSize;
     II.NumExecutedMutations++;
 
-    bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II);
+    bool FoundUniqFeatures = false;
+    bool NewCov = RunOne(CurrentUnitData, Size, /*MayDeleteFile=*/true, &II,
+                         &FoundUniqFeatures);
+    // Printf("FUF[%d] %d\n", i, FoundUniqFeatures);
     TryDetectingAMemoryLeak(CurrentUnitData, Size,
                             /*DuringInitialCorpusExecution*/ false);
-    if (NewCov)
+    if (NewCov) {
       ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
+      break;  // We will mutate this input more in the next rounds.
+    }
+    if (Options.ReduceDepth && !FoundUniqFeatures)
+        break;
   }
 }