From 38c36e3216d68c8907fb52001a64b5930097a6e2 Mon Sep 17 00:00:00 2001
From: Kostya Serebryany <kcc@google.com>
Date: Sat, 9 Jan 2016 03:46:08 +0000
Subject: [PATCH] [libFuzzer] debug prints in tracing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257249 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Fuzzer/FuzzerTraceState.cpp | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/Fuzzer/FuzzerTraceState.cpp b/lib/Fuzzer/FuzzerTraceState.cpp
index 83130444a16..36fc6dcfd23 100644
--- a/lib/Fuzzer/FuzzerTraceState.cpp
+++ b/lib/Fuzzer/FuzzerTraceState.cpp
@@ -170,6 +170,25 @@ struct TraceBasedMutation {
   uint8_t  Data[kMaxSize];
 };
 
+static void PrintDataByte(uint8_t Byte) {
+  if (Byte == '\\')
+    Printf("\\\\");
+  else if (Byte == '"')
+    Printf("\\\"");
+  else if (Byte >= 32 && Byte < 127)
+    Printf("%c", Byte);
+  else
+    Printf("\\x02x", Byte);
+}
+
+static void PrintData(const uint8_t *Data, size_t Size) {
+  Printf("\"");
+  for (size_t i = 0; i < Size; i++) {
+    PrintDataByte(Data[i]);
+  }
+  Printf("\"");
+}
+
 const size_t TraceBasedMutation::kMaxSize;
 
 class TraceState {
@@ -394,8 +413,14 @@ void TraceState::TraceMemcmpCallback(size_t CmpSize, const uint8_t *Data1,
                                      const uint8_t *Data2) {
   if (!RecordingTraces || !IsMyThread) return;
   CmpSize = std::min(CmpSize, TraceBasedMutation::kMaxSize);
-  TryToAddDesiredData(Data1, Data2, CmpSize);
-  TryToAddDesiredData(Data2, Data1, CmpSize);
+  int Added2 = TryToAddDesiredData(Data1, Data2, CmpSize);
+  int Added1 = TryToAddDesiredData(Data2, Data1, CmpSize);
+  if ((Added1 || Added2) && Options.Verbosity >= 3) {
+    Printf("MemCmp Added %d%d: ", Added1, Added2);
+    if (Added1) PrintData(Data1, CmpSize);
+    if (Added2) PrintData(Data2, CmpSize);
+    Printf("\n");
+  }
 }
 
 void TraceState::TraceSwitchCallback(uintptr_t PC, size_t ValSizeInBits,
-- 
2.34.1