1 files changed, 28 insertions, 5 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index 1b5e0265e13..37db6ee09e5 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -111,23 +111,46 @@ bool Fuzzer::RecordMaxCoverage(Fuzzer::Coverage *C) {
 // Leak detection is expensive, so we first check if there were more mallocs
 // than frees (using the sanitizer malloc hooks) and only then try to call lsan.
 struct MallocFreeTracer {
-  void Start() {
+  void Start(int TraceLevel) {
+    this->TraceLevel = TraceLevel;
+    if (TraceLevel)
+      Printf("MallocFreeTracer: START\n");
     Mallocs = 0;
     Frees = 0;
   }
   // Returns true if there were more mallocs than frees.
-  bool Stop() { return Mallocs > Frees; }
+  bool Stop() { 
+    if (TraceLevel)
+      Printf("MallocFreeTracer: STOP %zd %zd (%s)\n", Mallocs.load(),
+             Frees.load(), Mallocs == Frees ? "same" : "DIFFERENT");
+    bool Result = Mallocs > Frees;
+    Mallocs = 0;
+    Frees = 0;
+    TraceLevel = 0;
+    return Result;
+  }
   std::atomic<size_t> Mallocs;
   std::atomic<size_t> Frees;
+  int TraceLevel = 0;
 };
 
 static MallocFreeTracer AllocTracer;
 
 void MallocHook(const volatile void *ptr, size_t size) {
-  AllocTracer.Mallocs++;
+  size_t N = AllocTracer.Mallocs++;
+  if (int TraceLevel = AllocTracer.TraceLevel) {
+    Printf("MALLOC[%zd] %p %zd\n", N, ptr, size);
+    if (TraceLevel >= 2 && EF)
+      EF->__sanitizer_print_stack_trace();
+  }
 }
 void FreeHook(const volatile void *ptr) {
-  AllocTracer.Frees++;
+  size_t N = AllocTracer.Frees++;
+  if (int TraceLevel = AllocTracer.TraceLevel) {
+    Printf("FREE[%zd]   %p %zd\n", N, ptr);
+    if (TraceLevel >= 2 && EF)
+      EF->__sanitizer_print_stack_trace();
+  }
 }
 
 Fuzzer::Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
@@ -486,7 +509,7 @@ void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
   if (CurrentUnitData && CurrentUnitData != Data)
     memcpy(CurrentUnitData, Data, Size);
   CurrentUnitSize = Size;
-  AllocTracer.Start();
+  AllocTracer.Start(Options.TraceMalloc);
   UnitStartTime = system_clock::now();
   ResetCounters();  // Reset coverage right before the callback.
   TPC.ResetMaps();