➕ added libFuzzer

.gitignore

@@ -20,3 +20,4 @@ cmake-build-debug
 
 
 test/test-*
+test/fuzz_test/Fuzzer/.svn

test/fuzz_test/Fuzzer/CMakeLists.txt

@@ -0,0 +1,45 @@
+set(LIBFUZZER_FLAGS_BASE "${CMAKE_CXX_FLAGS}")
+# Disable the coverage and sanitizer instrumentation for the fuzzer itself.
+set(CMAKE_CXX_FLAGS "${LIBFUZZER_FLAGS_BASE} -fno-sanitize-coverage=trace-pc-guard,edge,trace-cmp,indirect-calls,8bit-counters -Werror")
+if( LLVM_USE_SANITIZE_COVERAGE )
+  if(NOT "${LLVM_USE_SANITIZER}" STREQUAL "Address")
+    message(FATAL_ERROR
+      "LibFuzzer and its tests require LLVM_USE_SANITIZER=Address and "
+      "LLVM_USE_SANITIZE_COVERAGE=YES to be set."
+      )
+  endif()
+  add_library(LLVMFuzzerNoMainObjects OBJECT
+    FuzzerCrossOver.cpp
+    FuzzerDriver.cpp
+    FuzzerExtFunctionsDlsym.cpp
+    FuzzerExtFunctionsWeak.cpp
+    FuzzerExtFunctionsWeakAlias.cpp
+    FuzzerIO.cpp
+    FuzzerIOPosix.cpp
+    FuzzerIOWindows.cpp
+    FuzzerLoop.cpp
+    FuzzerMerge.cpp
+    FuzzerMutate.cpp
+    FuzzerSHA1.cpp
+    FuzzerTracePC.cpp
+    FuzzerTraceState.cpp
+    FuzzerUtil.cpp
+    FuzzerUtilDarwin.cpp
+    FuzzerUtilLinux.cpp
+    FuzzerUtilPosix.cpp
+    FuzzerUtilWindows.cpp
+    )
+  add_library(LLVMFuzzerNoMain STATIC
+    $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
+    )
+  target_link_libraries(LLVMFuzzerNoMain ${PTHREAD_LIB})
+  add_library(LLVMFuzzer STATIC
+    FuzzerMain.cpp
+    $<TARGET_OBJECTS:LLVMFuzzerNoMainObjects>
+    )
+  target_link_libraries(LLVMFuzzer ${PTHREAD_LIB})
+
+  if( LLVM_INCLUDE_TESTS )
+    add_subdirectory(test)
+  endif()
+endif()

test/fuzz_test/Fuzzer/FuzzerCorpus.h

@@ -0,0 +1,217 @@
+//===- FuzzerCorpus.h - Internal header for the Fuzzer ----------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::InputCorpus
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_CORPUS
+#define LLVM_FUZZER_CORPUS
+
+#include "FuzzerDefs.h"
+#include "FuzzerIO.h"
+#include "FuzzerRandom.h"
+#include "FuzzerSHA1.h"
+#include "FuzzerTracePC.h"
+#include <numeric>
+#include <random>
+#include <unordered_set>
+
+namespace fuzzer {
+
+struct InputInfo {
+  Unit U;  // The actual input data.
+  uint8_t Sha1[kSHA1NumBytes];  // Checksum.
+  // Number of features that this input has and no smaller input has.
+  size_t NumFeatures = 0;
+  size_t Tmp = 0; // Used by ValidateFeatureSet.
+  // Stats.
+  size_t NumExecutedMutations = 0;
+  size_t NumSuccessfullMutations = 0;
+  bool MayDeleteFile = false;
+};
+
+class InputCorpus {
+ public:
+  static const size_t kFeatureSetSize = 1 << 16;
+  InputCorpus(const std::string &OutputCorpus) : OutputCorpus(OutputCorpus) {
+    memset(InputSizesPerFeature, 0, sizeof(InputSizesPerFeature));
+    memset(SmallestElementPerFeature, 0, sizeof(SmallestElementPerFeature));
+  }
+  ~InputCorpus() {
+    for (auto II : Inputs)
+      delete II;
+  }
+  size_t size() const { return Inputs.size(); }
+  size_t SizeInBytes() const {
+    size_t Res = 0;
+    for (auto II : Inputs)
+      Res += II->U.size();
+    return Res;
+  }
+  size_t NumActiveUnits() const {
+    size_t Res = 0;
+    for (auto II : Inputs)
+      Res += !II->U.empty();
+    return Res;
+  }
+  bool empty() const { return Inputs.empty(); }
+  const Unit &operator[] (size_t Idx) const { return Inputs[Idx]->U; }
+  void AddToCorpus(const Unit &U, size_t NumFeatures, bool MayDeleteFile = false) {
+    assert(!U.empty());
+    uint8_t Hash[kSHA1NumBytes];
+    if (FeatureDebug)
+      Printf("ADD_TO_CORPUS %zd NF %zd\n", Inputs.size(), NumFeatures);
+    ComputeSHA1(U.data(), U.size(), Hash);
+    Hashes.insert(Sha1ToString(Hash));
+    Inputs.push_back(new InputInfo());
+    InputInfo &II = *Inputs.back();
+    II.U = U;
+    II.NumFeatures = NumFeatures;
+    II.MayDeleteFile = MayDeleteFile;
+    memcpy(II.Sha1, Hash, kSHA1NumBytes);
+    UpdateCorpusDistribution();
+    ValidateFeatureSet();
+  }
+
+  bool HasUnit(const Unit &U) { return Hashes.count(Hash(U)); }
+  bool HasUnit(const std::string &H) { return Hashes.count(H); }
+  InputInfo &ChooseUnitToMutate(Random &Rand) {
+    InputInfo &II = *Inputs[ChooseUnitIdxToMutate(Rand)];
+    assert(!II.U.empty());
+    return II;
+  };
+
+  // Returns an index of random unit from the corpus to mutate.
+  // Hypothesis: units added to the corpus last are more likely to be
+  // interesting. This function gives more weight to the more recent units.
+  size_t ChooseUnitIdxToMutate(Random &Rand) {
+    size_t Idx = static_cast<size_t>(CorpusDistribution(Rand.Get_mt19937()));
+    assert(Idx < Inputs.size());
+    return Idx;
+  }
+
+  void PrintStats() {
+    for (size_t i = 0; i < Inputs.size(); i++) {
+      const auto &II = *Inputs[i];
+      Printf("  [%zd %s]\tsz: %zd\truns: %zd\tsucc: %zd\n", i,
+             Sha1ToString(II.Sha1).c_str(), II.U.size(),
+             II.NumExecutedMutations, II.NumSuccessfullMutations);
+    }
+  }
+
+  void PrintFeatureSet() {
+    for (size_t i = 0; i < kFeatureSetSize; i++) {
+      if(size_t Sz = GetFeature(i))
+        Printf("[%zd: id %zd sz%zd] ", i, SmallestElementPerFeature[i], Sz);
+    }
+    Printf("\n\t");
+    for (size_t i = 0; i < Inputs.size(); i++)
+      if (size_t N = Inputs[i]->NumFeatures)
+        Printf(" %zd=>%zd ", i, N);
+    Printf("\n");
+  }
+
+  void DeleteInput(size_t Idx) {
+    InputInfo &II = *Inputs[Idx];
+    if (!OutputCorpus.empty() && II.MayDeleteFile)
+      RemoveFile(DirPlusFile(OutputCorpus, Sha1ToString(II.Sha1)));
+    Unit().swap(II.U);
+    if (FeatureDebug)
+      Printf("EVICTED %zd\n", Idx);
+  }
+
+  bool AddFeature(size_t Idx, uint32_t NewSize, bool Shrink) {
+    assert(NewSize);
+    Idx = Idx % kFeatureSetSize;
+    uint32_t OldSize = GetFeature(Idx);
+    if (OldSize == 0 || (Shrink && OldSize > NewSize)) {
+      if (OldSize > 0) {
+        size_t OldIdx = SmallestElementPerFeature[Idx];
+        InputInfo &II = *Inputs[OldIdx];
+        assert(II.NumFeatures > 0);
+        II.NumFeatures--;
+        if (II.NumFeatures == 0)
+          DeleteInput(OldIdx);
+      }
+      if (FeatureDebug)
+        Printf("ADD FEATURE %zd sz %d\n", Idx, NewSize);
+      SmallestElementPerFeature[Idx] = Inputs.size();
+      InputSizesPerFeature[Idx] = NewSize;
+      CountingFeatures = true;
+      return true;
+    }
+    return false;
+  }
+
+  size_t NumFeatures() const {
+    size_t Res = 0;
+    for (size_t i = 0; i < kFeatureSetSize; i++)
+      Res += GetFeature(i) != 0;
+    return Res;
+  }
+
+  void ResetFeatureSet() {
+    assert(Inputs.empty());
+    memset(InputSizesPerFeature, 0, sizeof(InputSizesPerFeature));
+    memset(SmallestElementPerFeature, 0, sizeof(SmallestElementPerFeature));
+  }
+
+private:
+
+  static const bool FeatureDebug = false;
+
+  size_t GetFeature(size_t Idx) const { return InputSizesPerFeature[Idx]; }
+
+  void ValidateFeatureSet() {
+    if (!CountingFeatures) return;
+    if (FeatureDebug)
+      PrintFeatureSet();
+    for (size_t Idx = 0; Idx < kFeatureSetSize; Idx++)
+      if (GetFeature(Idx))
+        Inputs[SmallestElementPerFeature[Idx]]->Tmp++;
+    for (auto II: Inputs) {
+      if (II->Tmp != II->NumFeatures)
+        Printf("ZZZ %zd %zd\n", II->Tmp, II->NumFeatures);
+      assert(II->Tmp == II->NumFeatures);
+      II->Tmp = 0;
+    }
+  }
+
+  // Updates the probability distribution for the units in the corpus.
+  // Must be called whenever the corpus or unit weights are changed.
+  void UpdateCorpusDistribution() {
+    size_t N = Inputs.size();
+    Intervals.resize(N + 1);
+    Weights.resize(N);
+    std::iota(Intervals.begin(), Intervals.end(), 0);
+    if (CountingFeatures)
+      for (size_t i = 0; i < N; i++)
+        Weights[i] = Inputs[i]->NumFeatures * (i + 1);
+    else
+      std::iota(Weights.begin(), Weights.end(), 1);
+    CorpusDistribution = std::piecewise_constant_distribution<double>(
+        Intervals.begin(), Intervals.end(), Weights.begin());
+  }
+  std::piecewise_constant_distribution<double> CorpusDistribution;
+
+  std::vector<double> Intervals;
+  std::vector<double> Weights;
+
+  std::unordered_set<std::string> Hashes;
+  std::vector<InputInfo*> Inputs;
+
+  bool CountingFeatures = false;
+  uint32_t InputSizesPerFeature[kFeatureSetSize];
+  uint32_t SmallestElementPerFeature[kFeatureSetSize];
+
+  std::string OutputCorpus;
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_CORPUS

test/fuzz_test/Fuzzer/FuzzerCrossOver.cpp

@@ -0,0 +1,52 @@
+//===- FuzzerCrossOver.cpp - Cross over two test inputs -------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Cross over test inputs.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerDefs.h"
+#include "FuzzerMutate.h"
+#include "FuzzerRandom.h"
+#include <cstring>
+
+namespace fuzzer {
+
+// Cross Data1 and Data2, store the result (up to MaxOutSize bytes) in Out.
+size_t MutationDispatcher::CrossOver(const uint8_t *Data1, size_t Size1,
+                                     const uint8_t *Data2, size_t Size2,
+                                     uint8_t *Out, size_t MaxOutSize) {
+  assert(Size1 || Size2);
+  MaxOutSize = Rand(MaxOutSize) + 1;
+  size_t OutPos = 0;
+  size_t Pos1 = 0;
+  size_t Pos2 = 0;
+  size_t *InPos = &Pos1;
+  size_t InSize = Size1;
+  const uint8_t *Data = Data1;
+  bool CurrentlyUsingFirstData = true;
+  while (OutPos < MaxOutSize && (Pos1 < Size1 || Pos2 < Size2)) {
+    // Merge a part of Data into Out.
+    size_t OutSizeLeft = MaxOutSize - OutPos;
+    if (*InPos < InSize) {
+      size_t InSizeLeft = InSize - *InPos;
+      size_t MaxExtraSize = std::min(OutSizeLeft, InSizeLeft);
+      size_t ExtraSize = Rand(MaxExtraSize) + 1;
+      memcpy(Out + OutPos, Data + *InPos, ExtraSize);
+      OutPos += ExtraSize;
+      (*InPos) += ExtraSize;
+    }
+    // Use the other input data on the next iteration.
+    InPos  = CurrentlyUsingFirstData ? &Pos2 : &Pos1;
+    InSize = CurrentlyUsingFirstData ? Size2 : Size1;
+    Data   = CurrentlyUsingFirstData ? Data2 : Data1;
+    CurrentlyUsingFirstData = !CurrentlyUsingFirstData;
+  }
+  return OutPos;
+}
+
+}  // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerDefs.h

@@ -0,0 +1,89 @@
+//===- FuzzerDefs.h - Internal header for the Fuzzer ------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Basic definitions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_DEFS_H
+#define LLVM_FUZZER_DEFS_H
+
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <string>
+#include <vector>
+
+// Platform detection.
+#ifdef __linux__
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_LINUX 1
+#define LIBFUZZER_WINDOWS 0
+#elif __APPLE__
+#define LIBFUZZER_APPLE 1
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_WINDOWS 0
+#elif _WIN32
+#define LIBFUZZER_APPLE 0
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_WINDOWS 1
+#else
+#error "Support for your platform has not been implemented"
+#endif
+
+#define LIBFUZZER_POSIX LIBFUZZER_APPLE || LIBFUZZER_LINUX
+
+#ifdef __x86_64
+#define ATTRIBUTE_TARGET_POPCNT __attribute__((target("popcnt")))
+#else
+#define ATTRIBUTE_TARGET_POPCNT
+#endif
+
+
+#ifdef __clang__  // avoid gcc warning.
+#  define ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize("memory")))
+#else
+#  define ATTRIBUTE_NO_SANITIZE_MEMORY
+#endif
+
+namespace fuzzer {
+
+template <class T> T Min(T a, T b) { return a < b ? a : b; }
+template <class T> T Max(T a, T b) { return a > b ? a : b; }
+
+class Random;
+class Dictionary;
+class DictionaryEntry;
+class MutationDispatcher;
+struct FuzzingOptions;
+class InputCorpus;
+struct InputInfo;
+struct ExternalFunctions;
+
+// Global interface to functions that may or may not be available.
+extern ExternalFunctions *EF;
+
+typedef std::vector<uint8_t> Unit;
+typedef std::vector<Unit> UnitVector;
+typedef int (*UserCallback)(const uint8_t *Data, size_t Size);
+
+int FuzzerDriver(int *argc, char ***argv, UserCallback Callback);
+
+struct ScopedDoingMyOwnMemmem {
+  ScopedDoingMyOwnMemmem();
+  ~ScopedDoingMyOwnMemmem();
+};
+
+inline uint8_t  Bswap(uint8_t x)  { return x; }
+inline uint16_t Bswap(uint16_t x) { return __builtin_bswap16(x); }
+inline uint32_t Bswap(uint32_t x) { return __builtin_bswap32(x); }
+inline uint64_t Bswap(uint64_t x) { return __builtin_bswap64(x); }
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_DEFS_H

test/fuzz_test/Fuzzer/FuzzerDictionary.h

@@ -0,0 +1,124 @@
+//===- FuzzerDictionary.h - Internal header for the Fuzzer ------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::Dictionary
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_DICTIONARY_H
+#define LLVM_FUZZER_DICTIONARY_H
+
+#include "FuzzerDefs.h"
+#include "FuzzerIO.h"
+#include "FuzzerUtil.h"
+#include <algorithm>
+#include <limits>
+
+namespace fuzzer {
+// A simple POD sized array of bytes.
+template <size_t kMaxSize> class FixedWord {
+public:
+  FixedWord() {}
+  FixedWord(const uint8_t *B, uint8_t S) { Set(B, S); }
+
+  void Set(const uint8_t *B, uint8_t S) {
+    assert(S <= kMaxSize);
+    memcpy(Data, B, S);
+    Size = S;
+  }
+
+  bool operator==(const FixedWord<kMaxSize> &w) const {
+    return Size == w.Size && 0 == memcmp(Data, w.Data, Size);
+  }
+
+  bool operator<(const FixedWord<kMaxSize> &w) const {
+    if (Size != w.Size)
+      return Size < w.Size;
+    return memcmp(Data, w.Data, Size) < 0;
+  }
+
+  static size_t GetMaxSize() { return kMaxSize; }
+  const uint8_t *data() const { return Data; }
+  uint8_t size() const { return Size; }
+
+private:
+  uint8_t Size = 0;
+  uint8_t Data[kMaxSize];
+};
+
+typedef FixedWord<27> Word; // 28 bytes.
+
+class DictionaryEntry {
+ public:
+  DictionaryEntry() {}
+  DictionaryEntry(Word W) : W(W) {}
+  DictionaryEntry(Word W, size_t PositionHint) : W(W), PositionHint(PositionHint) {}
+  const Word &GetW() const { return W; }
+
+  bool HasPositionHint() const { return PositionHint != std::numeric_limits<size_t>::max(); }
+  size_t GetPositionHint() const {
+    assert(HasPositionHint());
+    return PositionHint;
+  }
+  void IncUseCount() { UseCount++; }
+  void IncSuccessCount() { SuccessCount++; }
+  size_t GetUseCount() const { return UseCount; }
+  size_t GetSuccessCount() const {return SuccessCount; }
+
+  void Print(const char *PrintAfter = "\n") {
+    PrintASCII(W.data(), W.size());
+    if (HasPositionHint())
+      Printf("@%zd", GetPositionHint());
+    Printf("%s", PrintAfter);
+  }
+
+private:
+  Word W;
+  size_t PositionHint = std::numeric_limits<size_t>::max();
+  size_t UseCount = 0;
+  size_t SuccessCount = 0;
+};
+
+class Dictionary {
+ public:
+  static const size_t kMaxDictSize = 1 << 14;
+
+  bool ContainsWord(const Word &W) const {
+    return std::any_of(begin(), end(), [&](const DictionaryEntry &DE) {
+      return DE.GetW() == W;
+    });
+  }
+  const DictionaryEntry *begin() const { return &DE[0]; }
+  const DictionaryEntry *end() const { return begin() + Size; }
+  DictionaryEntry & operator[] (size_t Idx) {
+    assert(Idx < Size);
+    return DE[Idx];
+  }
+  void push_back(DictionaryEntry DE) {
+    if (Size < kMaxDictSize)
+      this->DE[Size++] = DE;
+  }
+  void clear() { Size = 0; }
+  bool empty() const { return Size == 0; }
+  size_t size() const { return Size; }
+
+private:
+  DictionaryEntry DE[kMaxDictSize];
+  size_t Size = 0;
+};
+
+// Parses one dictionary entry.
+// If successfull, write the enty to Unit and returns true,
+// otherwise returns false.
+bool ParseOneDictionaryEntry(const std::string &Str, Unit *U);
+// Parses the dictionary file, fills Units, returns true iff all lines
+// were parsed succesfully.
+bool ParseDictionaryFile(const std::string &Text, std::vector<Unit> *Units);
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_DICTIONARY_H

test/fuzz_test/Fuzzer/FuzzerDriver.cpp

@@ -0,0 +1,545 @@
+//===- FuzzerDriver.cpp - FuzzerDriver function and flags -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// FuzzerDriver and flag parsing.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCorpus.h"
+#include "FuzzerInterface.h"
+#include "FuzzerInternal.h"
+#include "FuzzerIO.h"
+#include "FuzzerMutate.h"
+#include "FuzzerRandom.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <cstring>
+#include <mutex>
+#include <string>
+#include <thread>
+
+// This function should be present in the libFuzzer so that the client
+// binary can test for its existence.
+extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
+
+namespace fuzzer {
+
+// Program arguments.
+struct FlagDescription {
+  const char *Name;
+  const char *Description;
+  int   Default;
+  int   *IntFlag;
+  const char **StrFlag;
+  unsigned int *UIntFlag;
+};
+
+struct {
+#define FUZZER_DEPRECATED_FLAG(Name)
+#define FUZZER_FLAG_INT(Name, Default, Description) int Name;
+#define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
+#define FUZZER_FLAG_STRING(Name, Description) const char *Name;
+#include "FuzzerFlags.def"
+#undef FUZZER_DEPRECATED_FLAG
+#undef FUZZER_FLAG_INT
+#undef FUZZER_FLAG_UNSIGNED
+#undef FUZZER_FLAG_STRING
+} Flags;
+
+static const FlagDescription FlagDescriptions [] {
+#define FUZZER_DEPRECATED_FLAG(Name)                                           \
+  {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
+#define FUZZER_FLAG_INT(Name, Default, Description)                            \
+  {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
+#define FUZZER_FLAG_UNSIGNED(Name, Default, Description)                       \
+  {#Name,   Description, static_cast<int>(Default),                            \
+   nullptr, nullptr, &Flags.Name},
+#define FUZZER_FLAG_STRING(Name, Description)                                  \
+  {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
+#include "FuzzerFlags.def"
+#undef FUZZER_DEPRECATED_FLAG
+#undef FUZZER_FLAG_INT
+#undef FUZZER_FLAG_UNSIGNED
+#undef FUZZER_FLAG_STRING
+};
+
+static const size_t kNumFlags =
+    sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
+
+static std::vector<std::string> *Inputs;
+static std::string *ProgName;
+
+static void PrintHelp() {
+  Printf("Usage:\n");
+  auto Prog = ProgName->c_str();
+  Printf("\nTo run fuzzing pass 0 or more directories.\n");
+  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
+
+  Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
+  Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
+
+  Printf("\nFlags: (strictly in form -flag=value)\n");
+  size_t MaxFlagLen = 0;
+  for (size_t F = 0; F < kNumFlags; F++)
+    MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
+
+  for (size_t F = 0; F < kNumFlags; F++) {
+    const auto &D = FlagDescriptions[F];
+    if (strstr(D.Description, "internal flag") == D.Description) continue;
+    Printf(" %s", D.Name);
+    for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
+      Printf(" ");
+    Printf("\t");
+    Printf("%d\t%s\n", D.Default, D.Description);
+  }
+  Printf("\nFlags starting with '--' will be ignored and "
+            "will be passed verbatim to subprocesses.\n");
+}
+
+static const char *FlagValue(const char *Param, const char *Name) {
+  size_t Len = strlen(Name);
+  if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
+      Param[Len + 1] == '=')
+      return &Param[Len + 2];
+  return nullptr;
+}
+
+// Avoid calling stol as it triggers a bug in clang/glibc build.
+static long MyStol(const char *Str) {
+  long Res = 0;
+  long Sign = 1;
+  if (*Str == '-') {
+    Str++;
+    Sign = -1;
+  }
+  for (size_t i = 0; Str[i]; i++) {
+    char Ch = Str[i];
+    if (Ch < '0' || Ch > '9')
+      return Res;
+    Res = Res * 10 + (Ch - '0');
+  }
+  return Res * Sign;
+}
+
+static bool ParseOneFlag(const char *Param) {
+  if (Param[0] != '-') return false;
+  if (Param[1] == '-') {
+    static bool PrintedWarning = false;
+    if (!PrintedWarning) {
+      PrintedWarning = true;
+      Printf("INFO: libFuzzer ignores flags that start with '--'\n");
+    }
+    for (size_t F = 0; F < kNumFlags; F++)
+      if (FlagValue(Param + 1, FlagDescriptions[F].Name))
+        Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
+    return true;
+  }
+  for (size_t F = 0; F < kNumFlags; F++) {
+    const char *Name = FlagDescriptions[F].Name;
+    const char *Str = FlagValue(Param, Name);
+    if (Str)  {
+      if (FlagDescriptions[F].IntFlag) {
+        int Val = MyStol(Str);
+        *FlagDescriptions[F].IntFlag = Val;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %d\n", Name, Val);;
+        return true;
+      } else if (FlagDescriptions[F].UIntFlag) {
+        unsigned int Val = std::stoul(Str);
+        *FlagDescriptions[F].UIntFlag = Val;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %u\n", Name, Val);
+        return true;
+      } else if (FlagDescriptions[F].StrFlag) {
+        *FlagDescriptions[F].StrFlag = Str;
+        if (Flags.verbosity >= 2)
+          Printf("Flag: %s %s\n", Name, Str);
+        return true;
+      } else {  // Deprecated flag.
+        Printf("Flag: %s: deprecated, don't use\n", Name);
+        return true;
+      }
+    }
+  }
+  Printf("\n\nWARNING: unrecognized flag '%s'; "
+         "use -help=1 to list all flags\n\n", Param);
+  return true;
+}
+
+// We don't use any library to minimize dependencies.
+static void ParseFlags(const std::vector<std::string> &Args) {
+  for (size_t F = 0; F < kNumFlags; F++) {
+    if (FlagDescriptions[F].IntFlag)
+      *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
+    if (FlagDescriptions[F].UIntFlag)
+      *FlagDescriptions[F].UIntFlag =
+          static_cast<unsigned int>(FlagDescriptions[F].Default);
+    if (FlagDescriptions[F].StrFlag)
+      *FlagDescriptions[F].StrFlag = nullptr;
+  }
+  Inputs = new std::vector<std::string>;
+  for (size_t A = 1; A < Args.size(); A++) {
+    if (ParseOneFlag(Args[A].c_str())) continue;
+    Inputs->push_back(Args[A]);
+  }
+}
+
+static std::mutex Mu;
+
+static void PulseThread() {
+  while (true) {
+    SleepSeconds(600);
+    std::lock_guard<std::mutex> Lock(Mu);
+    Printf("pulse...\n");
+  }
+}
+
+static void WorkerThread(const std::string &Cmd, std::atomic<unsigned> *Counter,
+                         unsigned NumJobs, std::atomic<bool> *HasErrors) {
+  while (true) {
+    unsigned C = (*Counter)++;
+    if (C >= NumJobs) break;
+    std::string Log = "fuzz-" + std::to_string(C) + ".log";
+    std::string ToRun = Cmd + " > " + Log + " 2>&1\n";
+    if (Flags.verbosity)
+      Printf("%s", ToRun.c_str());
+    int ExitCode = ExecuteCommand(ToRun);
+    if (ExitCode != 0)
+      *HasErrors = true;
+    std::lock_guard<std::mutex> Lock(Mu);
+    Printf("================== Job %u exited with exit code %d ============\n",
+           C, ExitCode);
+    fuzzer::CopyFileToErr(Log);
+  }
+}
+
+std::string CloneArgsWithoutX(const std::vector<std::string> &Args,
+                              const char *X1, const char *X2) {
+  std::string Cmd;
+  for (auto &S : Args) {
+    if (FlagValue(S.c_str(), X1) || FlagValue(S.c_str(), X2))
+      continue;
+    Cmd += S + " ";
+  }
+  return Cmd;
+}
+
+static int RunInMultipleProcesses(const std::vector<std::string> &Args,
+                                  unsigned NumWorkers, unsigned NumJobs) {
+  std::atomic<unsigned> Counter(0);
+  std::atomic<bool> HasErrors(false);
+  std::string Cmd = CloneArgsWithoutX(Args, "jobs", "workers");
+  std::vector<std::thread> V;
+  std::thread Pulse(PulseThread);
+  Pulse.detach();
+  for (unsigned i = 0; i < NumWorkers; i++)
+    V.push_back(std::thread(WorkerThread, Cmd, &Counter, NumJobs, &HasErrors));
+  for (auto &T : V)
+    T.join();
+  return HasErrors ? 1 : 0;
+}
+
+static void RssThread(Fuzzer *F, size_t RssLimitMb) {
+  while (true) {
+    SleepSeconds(1);
+    size_t Peak = GetPeakRSSMb();
+    if (Peak > RssLimitMb)
+      F->RssLimitCallback();
+  }
+}
+
+static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
+  if (!RssLimitMb) return;
+  std::thread T(RssThread, F, RssLimitMb);
+  T.detach();
+}
+
+int RunOneTest(Fuzzer *F, const char *InputFilePath, size_t MaxLen) {
+  Unit U = FileToVector(InputFilePath);
+  if (MaxLen && MaxLen < U.size())
+    U.resize(MaxLen);
+  F->RunOne(U.data(), U.size());
+  F->TryDetectingAMemoryLeak(U.data(), U.size(), true);
+  return 0;
+}
+
+static bool AllInputsAreFiles() {
+  if (Inputs->empty()) return false;
+  for (auto &Path : *Inputs)
+    if (!IsFile(Path))
+      return false;
+  return true;
+}
+
+int MinimizeCrashInput(const std::vector<std::string> &Args) {
+  if (Inputs->size() != 1) {
+    Printf("ERROR: -minimize_crash should be given one input file\n");
+    exit(1);
+  }
+  std::string InputFilePath = Inputs->at(0);
+  std::string BaseCmd =
+      CloneArgsWithoutX(Args, "minimize_crash", "exact_artifact_path");
+  auto InputPos = BaseCmd.find(" " + InputFilePath + " ");
+  assert(InputPos != std::string::npos);
+  BaseCmd.erase(InputPos, InputFilePath.size() + 1);
+  if (Flags.runs <= 0 && Flags.max_total_time == 0) {
+    Printf("INFO: you need to specify -runs=N or "
+           "-max_total_time=N with -minimize_crash=1\n"
+           "INFO: defaulting to -max_total_time=600\n");
+    BaseCmd += " -max_total_time=600";
+  }
+  // BaseCmd += " >  /dev/null 2>&1 ";
+
+  std::string CurrentFilePath = InputFilePath;
+  while (true) {
+    Unit U = FileToVector(CurrentFilePath);
+    if (U.size() < 2) {
+      Printf("CRASH_MIN: '%s' is small enough\n", CurrentFilePath.c_str());
+      return 0;
+    }
+    Printf("CRASH_MIN: minimizing crash input: '%s' (%zd bytes)\n",
+           CurrentFilePath.c_str(), U.size());
+
+    auto Cmd = BaseCmd + " " + CurrentFilePath;
+
+    Printf("CRASH_MIN: executing: %s\n", Cmd.c_str());
+    int ExitCode = ExecuteCommand(Cmd);
+    if (ExitCode == 0) {
+      Printf("ERROR: the input %s did not crash\n", CurrentFilePath.c_str());
+      exit(1);
+    }
+    Printf("CRASH_MIN: '%s' (%zd bytes) caused a crash. Will try to minimize "
+           "it further\n",
+           CurrentFilePath.c_str(), U.size());
+
+    std::string ArtifactPath = "minimized-from-" + Hash(U);
+    Cmd += " -minimize_crash_internal_step=1 -exact_artifact_path=" +
+        ArtifactPath;
+    Printf("CRASH_MIN: executing: %s\n", Cmd.c_str());
+    ExitCode = ExecuteCommand(Cmd);
+    if (ExitCode == 0) {
+      if (Flags.exact_artifact_path) {
+        CurrentFilePath = Flags.exact_artifact_path;
+        WriteToFile(U, CurrentFilePath);
+      }
+      Printf("CRASH_MIN: failed to minimize beyond %s (%d bytes), exiting\n",
+             CurrentFilePath.c_str(), U.size());
+      return 0;
+    }
+    CurrentFilePath = ArtifactPath;
+    Printf("\n\n\n\n\n\n*********************************\n");
+  }
+  return 0;
+}
+
+int MinimizeCrashInputInternalStep(Fuzzer *F, InputCorpus *Corpus) {
+  assert(Inputs->size() == 1);
+  std::string InputFilePath = Inputs->at(0);
+  Unit U = FileToVector(InputFilePath);
+  assert(U.size() > 2);
+  Printf("INFO: Starting MinimizeCrashInputInternalStep: %zd\n", U.size());
+  Corpus->AddToCorpus(U, 0);
+  F->SetMaxInputLen(U.size());
+  F->SetMaxMutationLen(U.size() - 1);
+  F->MinimizeCrashLoop(U);
+  Printf("INFO: Done MinimizeCrashInputInternalStep, no crashes found\n");
+  exit(0);
+  return 0;
+}
+
+int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
+  using namespace fuzzer;
+  assert(argc && argv && "Argument pointers cannot be nullptr");
+  EF = new ExternalFunctions();
+  if (EF->LLVMFuzzerInitialize)
+    EF->LLVMFuzzerInitialize(argc, argv);
+  const std::vector<std::string> Args(*argv, *argv + *argc);
+  assert(!Args.empty());
+  ProgName = new std::string(Args[0]);
+  ParseFlags(Args);
+  if (Flags.help) {
+    PrintHelp();
+    return 0;
+  }
+
+  if (Flags.minimize_crash)
+    return MinimizeCrashInput(Args);
+
+  if (Flags.close_fd_mask & 2)
+    DupAndCloseStderr();
+  if (Flags.close_fd_mask & 1)
+    CloseStdout();
+
+  if (Flags.jobs > 0 && Flags.workers == 0) {
+    Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
+    if (Flags.workers > 1)
+      Printf("Running %u workers\n", Flags.workers);
+  }
+
+  if (Flags.workers > 0 && Flags.jobs > 0)
+    return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
+
+  const size_t kMaxSaneLen = 1 << 20;
+  const size_t kMinDefaultLen = 64;
+  FuzzingOptions Options;
+  Options.Verbosity = Flags.verbosity;
+  Options.MaxLen = Flags.max_len;
+  Options.UnitTimeoutSec = Flags.timeout;
+  Options.ErrorExitCode = Flags.error_exitcode;
+  Options.TimeoutExitCode = Flags.timeout_exitcode;
+  Options.MaxTotalTimeSec = Flags.max_total_time;
+  Options.DoCrossOver = Flags.cross_over;
+  Options.MutateDepth = Flags.mutate_depth;
+  Options.UseCounters = Flags.use_counters;
+  Options.UseIndirCalls = Flags.use_indir_calls;
+  Options.UseMemcmp = Flags.use_memcmp;
+  Options.UseMemmem = Flags.use_memmem;
+  Options.UseCmp = Flags.use_cmp;
+  Options.UseValueProfile = Flags.use_value_profile;
+  Options.Shrink = Flags.shrink;
+  Options.ShuffleAtStartUp = Flags.shuffle;
+  Options.PreferSmall = Flags.prefer_small;
+  Options.ReloadIntervalSec = Flags.reload;
+  Options.OnlyASCII = Flags.only_ascii;
+  Options.OutputCSV = Flags.output_csv;
+  Options.DetectLeaks = Flags.detect_leaks;
+  Options.TraceMalloc = Flags.trace_malloc;
+  Options.RssLimitMb = Flags.rss_limit_mb;
+  if (Flags.runs >= 0)
+    Options.MaxNumberOfRuns = Flags.runs;
+  if (!Inputs->empty() && !Flags.minimize_crash_internal_step)
+    Options.OutputCorpus = (*Inputs)[0];
+  Options.ReportSlowUnits = Flags.report_slow_units;
+  if (Flags.artifact_prefix)
+    Options.ArtifactPrefix = Flags.artifact_prefix;
+  if (Flags.exact_artifact_path)
+    Options.ExactArtifactPath = Flags.exact_artifact_path;
+  std::vector<Unit> Dictionary;
+  if (Flags.dict)
+    if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
+      return 1;
+  if (Flags.verbosity > 0 && !Dictionary.empty())
+    Printf("Dictionary: %zd entries\n", Dictionary.size());
+  bool DoPlainRun = AllInputsAreFiles();
+  Options.SaveArtifacts =
+      !DoPlainRun || Flags.minimize_crash_internal_step;
+  Options.PrintNewCovPcs = Flags.print_pcs;
+  Options.PrintFinalStats = Flags.print_final_stats;
+  Options.PrintCorpusStats = Flags.print_corpus_stats;
+  Options.PrintCoverage = Flags.print_coverage;
+  Options.DumpCoverage = Flags.dump_coverage;
+  if (Flags.exit_on_src_pos)
+    Options.ExitOnSrcPos = Flags.exit_on_src_pos;
+  if (Flags.exit_on_item)
+    Options.ExitOnItem = Flags.exit_on_item;
+
+  unsigned Seed = Flags.seed;
+  // Initialize Seed.
+  if (Seed == 0)
+    Seed = (std::chrono::system_clock::now().time_since_epoch().count() << 10) +
+           GetPid();
+  if (Flags.verbosity)
+    Printf("INFO: Seed: %u\n", Seed);
+
+  Random Rand(Seed);
+  auto *MD = new MutationDispatcher(Rand, Options);
+  auto *Corpus = new InputCorpus(Options.OutputCorpus);
+  auto *F = new Fuzzer(Callback, *Corpus, *MD, Options);
+
+  for (auto &U: Dictionary)
+    if (U.size() <= Word::GetMaxSize())
+      MD->AddWordToManualDictionary(Word(U.data(), U.size()));
+
+  StartRssThread(F, Flags.rss_limit_mb);
+
+  Options.HandleAbrt = Flags.handle_abrt;
+  Options.HandleBus = Flags.handle_bus;
+  Options.HandleFpe = Flags.handle_fpe;
+  Options.HandleIll = Flags.handle_ill;
+  Options.HandleInt = Flags.handle_int;
+  Options.HandleSegv = Flags.handle_segv;
+  Options.HandleTerm = Flags.handle_term;
+  SetSignalHandler(Options);
+
+  if (Flags.minimize_crash_internal_step)
+    return MinimizeCrashInputInternalStep(F, Corpus);
+
+  if (DoPlainRun) {
+    Options.SaveArtifacts = false;
+    int Runs = std::max(1, Flags.runs);
+    Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
+           Inputs->size(), Runs);
+    for (auto &Path : *Inputs) {
+      auto StartTime = system_clock::now();
+      Printf("Running: %s\n", Path.c_str());
+      for (int Iter = 0; Iter < Runs; Iter++)
+        RunOneTest(F, Path.c_str(), Options.MaxLen);
+      auto StopTime = system_clock::now();
+      auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
+      Printf("Executed %s in %zd ms\n", Path.c_str(), (long)MS);
+    }
+    Printf("***\n"
+           "*** NOTE: fuzzing was not performed, you have only\n"
+           "***       executed the target code on a fixed set of inputs.\n"
+           "***\n");
+    F->PrintFinalStats();
+    exit(0);
+  }
+
+  if (Flags.merge) {
+    if (Options.MaxLen == 0)
+      F->SetMaxInputLen(kMaxSaneLen);
+    if (TPC.UsingTracePcGuard()) {
+      if (Flags.merge_control_file)
+        F->CrashResistantMergeInternalStep(Flags.merge_control_file);
+      else
+        F->CrashResistantMerge(Args, *Inputs);
+    } else {
+      F->Merge(*Inputs);
+    }
+    exit(0);
+  }
+
+  size_t TemporaryMaxLen = Options.MaxLen ? Options.MaxLen : kMaxSaneLen;
+
+  UnitVector InitialCorpus;
+  for (auto &Inp : *Inputs) {
+    Printf("Loading corpus dir: %s\n", Inp.c_str());
+    ReadDirToVectorOfUnits(Inp.c_str(), &InitialCorpus, nullptr,
+                           TemporaryMaxLen, /*ExitOnError=*/false);
+  }
+
+  if (Options.MaxLen == 0) {
+    size_t MaxLen = 0;
+    for (auto &U : InitialCorpus)
+      MaxLen = std::max(U.size(), MaxLen);
+    F->SetMaxInputLen(std::min(std::max(kMinDefaultLen, MaxLen), kMaxSaneLen));
+  }
+
+  if (InitialCorpus.empty()) {
+    InitialCorpus.push_back(Unit({'\n'}));  // Valid ASCII input.
+    if (Options.Verbosity)
+      Printf("INFO: A corpus is not provided, starting from an empty corpus\n");
+  }
+  F->ShuffleAndMinimize(&InitialCorpus);
+  InitialCorpus.clear();  // Don't need this memory any more.
+  F->Loop();
+
+  if (Flags.verbosity)
+    Printf("Done %d runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
+           F->secondsSinceProcessStartUp());
+  F->PrintFinalStats();
+
+  exit(0);  // Don't let F destroy itself.
+}
+
+// Storage for global ExternalFunctions object.
+ExternalFunctions *EF = nullptr;
+
+}  // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerExtFunctions.def

@@ -0,0 +1,50 @@
+//===- FuzzerExtFunctions.def - External functions --------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// This defines the external function pointers that
+// ``fuzzer::ExternalFunctions`` should contain and try to initialize.  The
+// EXT_FUNC macro must be defined at the point of inclusion. The signature of
+// the macro is:
+//
+// EXT_FUNC(<name>, <return_type>, <function_signature>, <warn_if_missing>)
+//===----------------------------------------------------------------------===//
+
+// Optional user functions
+EXT_FUNC(LLVMFuzzerInitialize, int, (int *argc, char ***argv), false);
+EXT_FUNC(LLVMFuzzerCustomMutator, size_t,
+         (uint8_t * Data, size_t Size, size_t MaxSize, unsigned int Seed),
+         false);
+EXT_FUNC(LLVMFuzzerCustomCrossOver, size_t,
+         (const uint8_t * Data1, size_t Size1,
+          const uint8_t * Data2, size_t Size2,
+          uint8_t * Out, size_t MaxOutSize, unsigned int Seed),
+         false);
+
+// Sanitizer functions
+EXT_FUNC(__lsan_enable, void, (), false);
+EXT_FUNC(__lsan_disable, void, (), false);
+EXT_FUNC(__lsan_do_recoverable_leak_check, int, (), false);
+EXT_FUNC(__sanitizer_get_number_of_counters, size_t, (), false);
+EXT_FUNC(__sanitizer_install_malloc_and_free_hooks, int,
+         (void (*malloc_hook)(const volatile void *, size_t),
+          void (*free_hook)(const volatile void *)),
+         false);
+EXT_FUNC(__sanitizer_get_total_unique_caller_callee_pairs, size_t, (), false);
+EXT_FUNC(__sanitizer_get_total_unique_coverage, size_t, (), true);
+EXT_FUNC(__sanitizer_print_memory_profile, int, (size_t), false);
+EXT_FUNC(__sanitizer_print_stack_trace, void, (), true);
+EXT_FUNC(__sanitizer_symbolize_pc, void,
+         (void *, const char *fmt, char *out_buf, size_t out_buf_size), false);
+EXT_FUNC(__sanitizer_get_module_and_offset_for_pc, int,
+         (void *pc, char *module_path,
+         size_t module_path_len,void **pc_offset), false);
+EXT_FUNC(__sanitizer_reset_coverage, void, (), true);
+EXT_FUNC(__sanitizer_set_death_callback, void, (void (*)(void)), true);
+EXT_FUNC(__sanitizer_set_report_fd, void, (void*), false);
+EXT_FUNC(__sanitizer_update_counter_bitset_and_clear_counters, uintptr_t,
+  (uint8_t*), false);

test/fuzz_test/Fuzzer/FuzzerExtFunctions.h

@@ -0,0 +1,35 @@
+//===- FuzzerExtFunctions.h - Interface to external functions ---*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Defines an interface to (possibly optional) functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_EXT_FUNCTIONS_H
+#define LLVM_FUZZER_EXT_FUNCTIONS_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace fuzzer {
+
+struct ExternalFunctions {
+  // Initialize function pointers. Functions that are not available will be set
+  // to nullptr.  Do not call this constructor  before ``main()`` has been
+  // entered.
+  ExternalFunctions();
+
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  RETURN_TYPE(*NAME) FUNC_SIG = nullptr
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+};
+} // namespace fuzzer
+
+#endif

test/fuzz_test/Fuzzer/FuzzerExtFunctionsDlsym.cpp

@@ -0,0 +1,52 @@
+//===- FuzzerExtFunctionsDlsym.cpp - Interface to external functions ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Implementation for operating systems that support dlsym(). We only use it on
+// Apple platforms for now. We don't use this approach on Linux because it
+// requires that clients of LibFuzzer pass ``--export-dynamic`` to the linker.
+// That is a complication we don't wish to expose to clients right now.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_APPLE
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include <dlfcn.h>
+
+using namespace fuzzer;
+
+template <typename T>
+static T GetFnPtr(const char *FnName, bool WarnIfMissing) {
+  dlerror(); // Clear any previous errors.
+  void *Fn = dlsym(RTLD_DEFAULT, FnName);
+  if (Fn == nullptr) {
+    if (WarnIfMissing) {
+      const char *ErrorMsg = dlerror();
+      Printf("WARNING: Failed to find function \"%s\".", FnName);
+      if (ErrorMsg)
+        Printf(" Reason %s.", ErrorMsg);
+      Printf("\n");
+    }
+  }
+  return reinterpret_cast<T>(Fn);
+}
+
+namespace fuzzer {
+
+ExternalFunctions::ExternalFunctions() {
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  this->NAME = GetFnPtr<decltype(ExternalFunctions::NAME)>(#NAME, WARN)
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_APPLE

test/fuzz_test/Fuzzer/FuzzerExtFunctionsWeak.cpp

@@ -0,0 +1,53 @@
+//===- FuzzerExtFunctionsWeak.cpp - Interface to external functions -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Implementation for Linux. This relies on the linker's support for weak
+// symbols. We don't use this approach on Apple platforms because it requires
+// clients of LibFuzzer to pass ``-U _<symbol_name>`` to the linker to allow
+// weak symbols to be undefined. That is a complication we don't want to expose
+// to clients right now.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_LINUX
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+
+extern "C" {
+// Declare these symbols as weak to allow them to be optionally defined.
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  __attribute__((weak)) RETURN_TYPE NAME FUNC_SIG
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+using namespace fuzzer;
+
+static void CheckFnPtr(void *FnPtr, const char *FnName, bool WarnIfMissing) {
+  if (FnPtr == nullptr && WarnIfMissing) {
+    Printf("WARNING: Failed to find function \"%s\".\n", FnName);
+  }
+}
+
+namespace fuzzer {
+
+ExternalFunctions::ExternalFunctions() {
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  this->NAME = ::NAME;                                                         \
+  CheckFnPtr((void *)::NAME, #NAME, WARN);
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_LINUX

test/fuzz_test/Fuzzer/FuzzerExtFunctionsWeakAlias.cpp

@@ -0,0 +1,56 @@
+//===- FuzzerExtFunctionsWeakAlias.cpp - Interface to external functions --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Implementation using weak aliases. Works for Windows.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_WINDOWS
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+
+using namespace fuzzer;
+
+extern "C" {
+// Declare these symbols as weak to allow them to be optionally defined.
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  RETURN_TYPE NAME##Def FUNC_SIG {                                             \
+    Printf("ERROR: Function \"%s\" not defined.\n", #NAME);                    \
+    exit(1);                                                                   \
+  }                                                                            \
+  RETURN_TYPE NAME FUNC_SIG __attribute__((weak, alias(#NAME "Def")));
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+template <typename T>
+static T *GetFnPtr(T *Fun, T *FunDef, const char *FnName, bool WarnIfMissing) {
+  if (Fun == FunDef) {
+    if (WarnIfMissing)
+      Printf("WARNING: Failed to find function \"%s\".\n", FnName);
+    return nullptr;
+  }
+  return Fun;
+}
+
+namespace fuzzer {
+
+ExternalFunctions::ExternalFunctions() {
+#define EXT_FUNC(NAME, RETURN_TYPE, FUNC_SIG, WARN)                            \
+  this->NAME = GetFnPtr<decltype(::NAME)>(::NAME, ::NAME##Def, #NAME, WARN);
+
+#include "FuzzerExtFunctions.def"
+
+#undef EXT_FUNC
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_WINDOWS

test/fuzz_test/Fuzzer/FuzzerFlags.def

@@ -0,0 +1,115 @@
+//===- FuzzerFlags.def - Run-time flags -------------------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Flags. FUZZER_FLAG_INT/FUZZER_FLAG_STRING macros should be defined at the
+// point of inclusion. We are not using any flag parsing library for better
+// portability and independence.
+//===----------------------------------------------------------------------===//
+FUZZER_FLAG_INT(verbosity, 1, "Verbosity level.")
+FUZZER_FLAG_UNSIGNED(seed, 0, "Random seed. If 0, seed is generated.")
+FUZZER_FLAG_INT(runs, -1,
+            "Number of individual test runs (-1 for infinite runs).")
+FUZZER_FLAG_INT(max_len, 0, "Maximum length of the test input. "
+    "If 0, libFuzzer tries to guess a good value based on the corpus "
+    "and reports it. ")
+FUZZER_FLAG_INT(cross_over, 1, "If 1, cross over inputs.")
+FUZZER_FLAG_INT(mutate_depth, 5,
+            "Apply this number of consecutive mutations to each input.")
+FUZZER_FLAG_INT(shuffle, 1, "Shuffle inputs at startup")
+FUZZER_FLAG_INT(prefer_small, 1,
+    "If 1, always prefer smaller inputs during the corpus shuffle.")
+FUZZER_FLAG_INT(
+    timeout, 1200,
+    "Timeout in seconds (if positive). "
+    "If one unit runs more than this number of seconds the process will abort.")
+FUZZER_FLAG_INT(error_exitcode, 77, "When libFuzzer itself reports a bug "
+  "this exit code will be used.")
+FUZZER_FLAG_INT(timeout_exitcode, 77, "When libFuzzer reports a timeout "
+  "this exit code will be used.")
+FUZZER_FLAG_INT(max_total_time, 0, "If positive, indicates the maximal total "
+                                   "time in seconds to run the fuzzer.")
+FUZZER_FLAG_INT(help, 0, "Print help.")
+FUZZER_FLAG_INT(merge, 0, "If 1, the 2-nd, 3-rd, etc corpora will be "
+  "merged into the 1-st corpus. Only interesting units will be taken. "
+  "This flag can be used to minimize a corpus.")
+FUZZER_FLAG_STRING(merge_control_file, "internal flag")
+FUZZER_FLAG_INT(minimize_crash, 0, "If 1, minimizes the provided"
+  " crash input. Use with -runs=N or -max_total_time=N to limit "
+  "the number attempts")
+FUZZER_FLAG_INT(minimize_crash_internal_step, 0, "internal flag")
+FUZZER_FLAG_INT(use_counters, 1, "Use coverage counters")
+FUZZER_FLAG_INT(use_indir_calls, 1, "Use indirect caller-callee counters")
+FUZZER_FLAG_INT(use_memcmp, 1,
+                "Use hints from intercepting memcmp, strcmp, etc")
+FUZZER_FLAG_INT(use_memmem, 1,
+                "Use hints from intercepting memmem, strstr, etc")
+FUZZER_FLAG_INT(use_value_profile, 0,
+                "Experimental. Use value profile to guide fuzzing.")
+FUZZER_FLAG_INT(use_cmp, 1, "Use CMP traces to guide mutations")
+FUZZER_FLAG_INT(shrink, 0, "Experimental. Try to shrink corpus elements.")
+FUZZER_FLAG_UNSIGNED(jobs, 0, "Number of jobs to run. If jobs >= 1 we spawn"
+                          " this number of jobs in separate worker processes"
+                          " with stdout/stderr redirected to fuzz-JOB.log.")
+FUZZER_FLAG_UNSIGNED(workers, 0,
+            "Number of simultaneous worker processes to run the jobs."
+            " If zero, \"min(jobs,NumberOfCpuCores()/2)\" is used.")
+FUZZER_FLAG_INT(reload, 1,
+                "Reload the main corpus every <N> seconds to get new units"
+                " discovered by other processes. If 0, disabled")
+FUZZER_FLAG_INT(report_slow_units, 10,
+    "Report slowest units if they run for more than this number of seconds.")
+FUZZER_FLAG_INT(only_ascii, 0,
+                "If 1, generate only ASCII (isprint+isspace) inputs.")
+FUZZER_FLAG_STRING(dict, "Experimental. Use the dictionary file.")
+FUZZER_FLAG_STRING(artifact_prefix, "Write fuzzing artifacts (crash, "
+                                    "timeout, or slow inputs) as "
+                                    "$(artifact_prefix)file")
+FUZZER_FLAG_STRING(exact_artifact_path,
+                   "Write the single artifact on failure (crash, timeout) "
+                   "as $(exact_artifact_path). This overrides -artifact_prefix "
+                   "and will not use checksum in the file name. Do not "
+                   "use the same path for several parallel processes.")
+FUZZER_FLAG_INT(output_csv, 0, "Enable pulse output in CSV format.")
+FUZZER_FLAG_INT(print_pcs, 0, "If 1, print out newly covered PCs.")
+FUZZER_FLAG_INT(print_final_stats, 0, "If 1, print statistics at exit.")
+FUZZER_FLAG_INT(print_corpus_stats, 0,
+  "If 1, print statistics on corpus elements at exit.")
+FUZZER_FLAG_INT(print_coverage, 0, "If 1, print coverage information at exit."
+                                   " Experimental, only with trace-pc-guard")
+FUZZER_FLAG_INT(dump_coverage, 0, "If 1, dump coverage information at exit."
+                                  " Experimental, only with trace-pc-guard")
+FUZZER_FLAG_INT(handle_segv, 1, "If 1, try to intercept SIGSEGV.")
+FUZZER_FLAG_INT(handle_bus, 1, "If 1, try to intercept SIGSEGV.")
+FUZZER_FLAG_INT(handle_abrt, 1, "If 1, try to intercept SIGABRT.")
+FUZZER_FLAG_INT(handle_ill, 1, "If 1, try to intercept SIGILL.")
+FUZZER_FLAG_INT(handle_fpe, 1, "If 1, try to intercept SIGFPE.")
+FUZZER_FLAG_INT(handle_int, 1, "If 1, try to intercept SIGINT.")
+FUZZER_FLAG_INT(handle_term, 1, "If 1, try to intercept SIGTERM.")
+FUZZER_FLAG_INT(close_fd_mask, 0, "If 1, close stdout at startup; "
+    "if 2, close stderr; if 3, close both. "
+    "Be careful, this will also close e.g. asan's stderr/stdout.")
+FUZZER_FLAG_INT(detect_leaks, 1, "If 1, and if LeakSanitizer is enabled "
+    "try to detect memory leaks during fuzzing (i.e. not only at shut down).")
+FUZZER_FLAG_INT(trace_malloc, 0, "If >= 1 will print all mallocs/frees. "
+    "If >= 2 will also print stack traces.")
+FUZZER_FLAG_INT(rss_limit_mb, 2048, "If non-zero, the fuzzer will exit upon"
+    "reaching this limit of RSS memory usage.")
+FUZZER_FLAG_STRING(exit_on_src_pos, "Exit if a newly found PC originates"
+    " from the given source location. Example: -exit_on_src_pos=foo.cc:123. "
+    "Used primarily for testing libFuzzer itself.")
+FUZZER_FLAG_STRING(exit_on_item, "Exit if an item with a given sha1 sum"
+    " was added to the corpus. "
+    "Used primarily for testing libFuzzer itself.")
+
+FUZZER_DEPRECATED_FLAG(exit_on_first)
+FUZZER_DEPRECATED_FLAG(save_minimized_corpus)
+FUZZER_DEPRECATED_FLAG(sync_command)
+FUZZER_DEPRECATED_FLAG(sync_timeout)
+FUZZER_DEPRECATED_FLAG(test_single_input)
+FUZZER_DEPRECATED_FLAG(drill)
+FUZZER_DEPRECATED_FLAG(truncate_units)

test/fuzz_test/Fuzzer/FuzzerIO.cpp

@@ -0,0 +1,117 @@
+//===- FuzzerIO.cpp - IO utils. -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// IO functions.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerIO.h"
+#include "FuzzerDefs.h"
+#include "FuzzerExtFunctions.h"
+#include <algorithm>
+#include <cstdarg>
+#include <fstream>
+#include <iterator>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+namespace fuzzer {
+
+static FILE *OutputFile = stderr;
+
+long GetEpoch(const std::string &Path) {
+  struct stat St;
+  if (stat(Path.c_str(), &St))
+    return 0;  // Can't stat, be conservative.
+  return St.st_mtime;
+}
+
+Unit FileToVector(const std::string &Path, size_t MaxSize, bool ExitOnError) {
+  std::ifstream T(Path);
+  if (ExitOnError && !T) {
+    Printf("No such directory: %s; exiting\n", Path.c_str());
+    exit(1);
+  }
+
+  T.seekg(0, T.end);
+  size_t FileLen = T.tellg();
+  if (MaxSize)
+    FileLen = std::min(FileLen, MaxSize);
+
+  T.seekg(0, T.beg);
+  Unit Res(FileLen);
+  T.read(reinterpret_cast<char *>(Res.data()), FileLen);
+  return Res;
+}
+
+std::string FileToString(const std::string &Path) {
+  std::ifstream T(Path);
+  return std::string((std::istreambuf_iterator<char>(T)),
+                     std::istreambuf_iterator<char>());
+}
+
+void CopyFileToErr(const std::string &Path) {
+  Printf("%s", FileToString(Path).c_str());
+}
+
+void WriteToFile(const Unit &U, const std::string &Path) {
+  // Use raw C interface because this function may be called from a sig handler.
+  FILE *Out = fopen(Path.c_str(), "w");
+  if (!Out) return;
+  fwrite(U.data(), sizeof(U[0]), U.size(), Out);
+  fclose(Out);
+}
+
+void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
+                            long *Epoch, size_t MaxSize, bool ExitOnError) {
+  long E = Epoch ? *Epoch : 0;
+  std::vector<std::string> Files;
+  ListFilesInDirRecursive(Path, Epoch, &Files, /*TopDir*/true);
+  size_t NumLoaded = 0;
+  for (size_t i = 0; i < Files.size(); i++) {
+    auto &X = Files[i];
+    if (Epoch && GetEpoch(X) < E) continue;
+    NumLoaded++;
+    if ((NumLoaded & (NumLoaded - 1)) == 0 && NumLoaded >= 1024)
+      Printf("Loaded %zd/%zd files from %s\n", NumLoaded, Files.size(), Path);
+    auto S = FileToVector(X, MaxSize, ExitOnError);
+    if (!S.empty())
+      V->push_back(S);
+  }
+}
+
+std::string DirPlusFile(const std::string &DirPath,
+                        const std::string &FileName) {
+  return DirPath + GetSeparator() + FileName;
+}
+
+void DupAndCloseStderr() {
+  int OutputFd = DuplicateFile(2);
+  if (OutputFd > 0) {
+    FILE *NewOutputFile = OpenFile(OutputFd, "w");
+    if (NewOutputFile) {
+      OutputFile = NewOutputFile;
+      if (EF->__sanitizer_set_report_fd)
+        EF->__sanitizer_set_report_fd(reinterpret_cast<void *>(OutputFd));
+      CloseFile(2);
+    }
+  }
+}
+
+void CloseStdout() {
+  CloseFile(1);
+}
+
+void Printf(const char *Fmt, ...) {
+  va_list ap;
+  va_start(ap, Fmt);
+  vfprintf(OutputFile, Fmt, ap);
+  va_end(ap);
+  fflush(OutputFile);
+}
+
+}  // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerIO.h

@@ -0,0 +1,64 @@
+//===- FuzzerIO.h - Internal header for IO utils ----------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// IO interface.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_IO_H
+#define LLVM_FUZZER_IO_H
+
+#include "FuzzerDefs.h"
+
+namespace fuzzer {
+
+long GetEpoch(const std::string &Path);
+
+Unit FileToVector(const std::string &Path, size_t MaxSize = 0,
+                  bool ExitOnError = true);
+
+std::string FileToString(const std::string &Path);
+
+void CopyFileToErr(const std::string &Path);
+
+void WriteToFile(const Unit &U, const std::string &Path);
+
+void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
+                            long *Epoch, size_t MaxSize, bool ExitOnError);
+
+// Returns "Dir/FileName" or equivalent for the current OS.
+std::string DirPlusFile(const std::string &DirPath,
+                        const std::string &FileName);
+
+// Returns the name of the dir, similar to the 'dirname' utility.
+std::string DirName(const std::string &FileName);
+
+void DupAndCloseStderr();
+
+void CloseStdout();
+
+void Printf(const char *Fmt, ...);
+
+// Platform specific functions:
+bool IsFile(const std::string &Path);
+
+void ListFilesInDirRecursive(const std::string &Dir, long *Epoch,
+                             std::vector<std::string> *V, bool TopDir);
+
+char GetSeparator();
+
+FILE* OpenFile(int Fd, const char *Mode);
+
+int CloseFile(int Fd);
+
+int DuplicateFile(int Fd);
+
+void RemoveFile(const std::string &Path);
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_IO_H

test/fuzz_test/Fuzzer/FuzzerIOPosix.cpp

@@ -0,0 +1,88 @@
+//===- FuzzerIOPosix.cpp - IO utils for Posix. ----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// IO functions implementation using Posix API.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_POSIX
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include <cstdarg>
+#include <cstdio>
+#include <dirent.h>
+#include <fstream>
+#include <iterator>
+#include <libgen.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+namespace fuzzer {
+
+bool IsFile(const std::string &Path) {
+  struct stat St;
+  if (stat(Path.c_str(), &St))
+    return false;
+  return S_ISREG(St.st_mode);
+}
+
+void ListFilesInDirRecursive(const std::string &Dir, long *Epoch,
+                             std::vector<std::string> *V, bool TopDir) {
+  auto E = GetEpoch(Dir);
+  if (Epoch)
+    if (E && *Epoch >= E) return;
+
+  DIR *D = opendir(Dir.c_str());
+  if (!D) {
+    Printf("No such directory: %s; exiting\n", Dir.c_str());
+    exit(1);
+  }
+  while (auto E = readdir(D)) {
+    std::string Path = DirPlusFile(Dir, E->d_name);
+    if (E->d_type == DT_REG || E->d_type == DT_LNK)
+      V->push_back(Path);
+    else if (E->d_type == DT_DIR && *E->d_name != '.')
+      ListFilesInDirRecursive(Path, Epoch, V, false);
+  }
+  closedir(D);
+  if (Epoch && TopDir)
+    *Epoch = E;
+}
+
+char GetSeparator() {
+  return '/';
+}
+
+FILE* OpenFile(int Fd, const char* Mode) {
+  return fdopen(Fd, Mode);
+}
+
+int CloseFile(int fd) {
+  return close(fd);
+}
+
+int DuplicateFile(int Fd) {
+  return dup(Fd);
+}
+
+void RemoveFile(const std::string &Path) {
+  unlink(Path.c_str());
+}
+
+std::string DirName(const std::string &FileName) {
+  char *Tmp = new char[FileName.size() + 1];
+  memcpy(Tmp, FileName.c_str(), FileName.size() + 1);
+  std::string Res = dirname(Tmp);
+  delete [] Tmp;
+  return Res;
+}
+
+}  // namespace fuzzer
+
+#endif // LIBFUZZER_POSIX

test/fuzz_test/Fuzzer/FuzzerIOWindows.cpp

@@ -0,0 +1,282 @@
+//===- FuzzerIOWindows.cpp - IO utils for Windows. ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// IO functions implementation for Windows.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_WINDOWS
+
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include <cstdarg>
+#include <cstdio>
+#include <fstream>
+#include <io.h>
+#include <iterator>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <windows.h>
+
+namespace fuzzer {
+
+static bool IsFile(const std::string &Path, const DWORD &FileAttributes) {
+
+  if (FileAttributes & FILE_ATTRIBUTE_NORMAL)
+    return true;
+
+  if (FileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+    return false;
+
+  HANDLE FileHandle(
+      CreateFileA(Path.c_str(), 0, FILE_SHARE_READ, NULL, OPEN_EXISTING,
+                  FILE_FLAG_BACKUP_SEMANTICS, 0));
+
+  if (FileHandle == INVALID_HANDLE_VALUE) {
+    Printf("CreateFileA() failed for \"%s\" (Error code: %lu).\n", Path.c_str(),
+        GetLastError());
+    return false;
+  }
+
+  DWORD FileType = GetFileType(FileHandle);
+
+  if (FileType == FILE_TYPE_UNKNOWN) {
+    Printf("GetFileType() failed for \"%s\" (Error code: %lu).\n", Path.c_str(),
+        GetLastError());
+    CloseHandle(FileHandle);
+    return false;
+  }
+
+  if (FileType != FILE_TYPE_DISK) {
+    CloseHandle(FileHandle);
+    return false;
+  }
+
+  CloseHandle(FileHandle);
+  return true;
+}
+
+bool IsFile(const std::string &Path) {
+  DWORD Att = GetFileAttributesA(Path.c_str());
+
+  if (Att == INVALID_FILE_ATTRIBUTES) {
+    Printf("GetFileAttributesA() failed for \"%s\" (Error code: %lu).\n",
+        Path.c_str(), GetLastError());
+    return false;
+  }
+
+  return IsFile(Path, Att);
+}
+
+void ListFilesInDirRecursive(const std::string &Dir, long *Epoch,
+                             std::vector<std::string> *V, bool TopDir) {
+  auto E = GetEpoch(Dir);
+  if (Epoch)
+    if (E && *Epoch >= E) return;
+
+  std::string Path(Dir);
+  assert(!Path.empty());
+  if (Path.back() != '\\')
+      Path.push_back('\\');
+  Path.push_back('*');
+
+  // Get the first directory entry.
+  WIN32_FIND_DATAA FindInfo;
+  HANDLE FindHandle(FindFirstFileA(Path.c_str(), &FindInfo));
+  if (FindHandle == INVALID_HANDLE_VALUE)
+  {
+    Printf("No file found in: %s.\n", Dir.c_str());
+    return;
+  }
+
+  do {
+    std::string FileName = DirPlusFile(Dir, FindInfo.cFileName);
+
+    if (FindInfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
+      size_t FilenameLen = strlen(FindInfo.cFileName);
+      if ((FilenameLen == 1 && FindInfo.cFileName[0] == '.') ||
+          (FilenameLen == 2 && FindInfo.cFileName[0] == '.' &&
+                               FindInfo.cFileName[1] == '.'))
+        continue;
+
+      ListFilesInDirRecursive(FileName, Epoch, V, false);
+    }
+    else if (IsFile(FileName, FindInfo.dwFileAttributes))
+      V->push_back(FileName);
+  } while (FindNextFileA(FindHandle, &FindInfo));
+
+  DWORD LastError = GetLastError();
+  if (LastError != ERROR_NO_MORE_FILES)
+    Printf("FindNextFileA failed (Error code: %lu).\n", LastError);
+
+  FindClose(FindHandle);
+
+  if (Epoch && TopDir)
+    *Epoch = E;
+}
+
+char GetSeparator() {
+  return '\\';
+}
+
+FILE* OpenFile(int Fd, const char* Mode) {
+  return _fdopen(Fd, Mode);
+}
+
+int CloseFile(int Fd) {
+  return _close(Fd);
+}
+
+int DuplicateFile(int Fd) {
+  return _dup(Fd);
+}
+
+void RemoveFile(const std::string &Path) {
+  _unlink(Path.c_str());
+}
+
+static bool IsSeparator(char C) {
+  return C == '\\' || C == '/';
+}
+
+// Parse disk designators, like "C:\". If Relative == true, also accepts: "C:".
+// Returns number of characters considered if successful.
+static size_t ParseDrive(const std::string &FileName, const size_t Offset,
+                         bool Relative = true) {
+  if (Offset + 1 >= FileName.size() || FileName[Offset + 1] != ':')
+    return 0;
+  if (Offset + 2 >= FileName.size() || !IsSeparator(FileName[Offset + 2])) {
+    if (!Relative) // Accept relative path?
+      return 0;
+    else
+      return 2;
+  }
+  return 3;
+}
+
+// Parse a file name, like: SomeFile.txt
+// Returns number of characters considered if successful.
+static size_t ParseFileName(const std::string &FileName, const size_t Offset) {
+  size_t Pos = Offset;
+  const size_t End = FileName.size();
+  for(; Pos < End && !IsSeparator(FileName[Pos]); ++Pos)
+    ;
+  return Pos - Offset;
+}
+
+// Parse a directory ending in separator, like: SomeDir\
+// Returns number of characters considered if successful.
+static size_t ParseDir(const std::string &FileName, const size_t Offset) {
+  size_t Pos = Offset;
+  const size_t End = FileName.size();
+  if (Pos >= End || IsSeparator(FileName[Pos]))
+    return 0;
+  for(; Pos < End && !IsSeparator(FileName[Pos]); ++Pos)
+    ;
+  if (Pos >= End)
+    return 0;
+  ++Pos; // Include separator.
+  return Pos - Offset;
+}
+
+// Parse a servername and share, like: SomeServer\SomeShare\
+// Returns number of characters considered if successful.
+static size_t ParseServerAndShare(const std::string &FileName,
+                                  const size_t Offset) {
+  size_t Pos = Offset, Res;
+  if (!(Res = ParseDir(FileName, Pos)))
+    return 0;
+  Pos += Res;
+  if (!(Res = ParseDir(FileName, Pos)))
+    return 0;
+  Pos += Res;
+  return Pos - Offset;
+}
+
+// Parse the given Ref string from the position Offset, to exactly match the given
+// string Patt.
+// Returns number of characters considered if successful.
+static size_t ParseCustomString(const std::string &Ref, size_t Offset,
+                                const char *Patt) {
+  size_t Len = strlen(Patt);
+  if (Offset + Len > Ref.size())
+    return 0;
+  return Ref.compare(Offset, Len, Patt) == 0 ? Len : 0;
+}
+
+// Parse a location, like:
+// \\?\UNC\Server\Share\  \\?\C:\  \\Server\Share\  \  C:\  C:
+// Returns number of characters considered if successful.
+static size_t ParseLocation(const std::string &FileName) {
+  size_t Pos = 0, Res;
+
+  if ((Res = ParseCustomString(FileName, Pos, R"(\\?\)"))) {
+    Pos += Res;
+    if ((Res = ParseCustomString(FileName, Pos, R"(UNC\)"))) {
+      Pos += Res;
+      if ((Res = ParseServerAndShare(FileName, Pos)))
+        return Pos + Res;
+      return 0;
+    }
+    if ((Res = ParseDrive(FileName, Pos, false)))
+      return Pos + Res;
+    return 0;
+  }
+
+  if (Pos < FileName.size() && IsSeparator(FileName[Pos])) {
+    ++Pos;
+    if (Pos < FileName.size() && IsSeparator(FileName[Pos])) {
+      ++Pos;
+      if ((Res = ParseServerAndShare(FileName, Pos)))
+        return Pos + Res;
+      return 0;
+    }
+    return Pos;
+  }
+
+  if ((Res = ParseDrive(FileName, Pos)))
+    return Pos + Res;
+
+  return Pos;
+}
+
+std::string DirName(const std::string &FileName) {
+  size_t LocationLen = ParseLocation(FileName);
+  size_t DirLen = 0, Res;
+  while ((Res = ParseDir(FileName, LocationLen + DirLen)))
+    DirLen += Res;
+  size_t FileLen = ParseFileName(FileName, LocationLen + DirLen);
+
+  if (LocationLen + DirLen + FileLen != FileName.size()) {
+    Printf("DirName() failed for \"%s\", invalid path.\n", FileName.c_str());
+    exit(1);
+  }
+
+  if (DirLen) {
+    --DirLen; // Remove trailing separator.
+    if (!FileLen) { // Path ended in separator.
+      assert(DirLen);
+      // Remove file name from Dir.
+      while (DirLen && !IsSeparator(FileName[LocationLen + DirLen - 1]))
+        --DirLen;
+      if (DirLen) // Remove trailing separator.
+        --DirLen;
+    }
+  }
+
+  if (!LocationLen) { // Relative path.
+    if (!DirLen)
+      return ".";
+    return std::string(".\\").append(FileName, 0, DirLen);
+  }
+
+  return FileName.substr(0, LocationLen + DirLen);
+}
+
+}  // namespace fuzzer
+
+#endif // LIBFUZZER_WINDOWS

test/fuzz_test/Fuzzer/FuzzerInterface.h

@@ -0,0 +1,67 @@
+//===- FuzzerInterface.h - Interface header for the Fuzzer ------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Define the interface between libFuzzer and the library being tested.
+//===----------------------------------------------------------------------===//
+
+// NOTE: the libFuzzer interface is thin and in the majority of cases
+// you should not include this file into your target. In 95% of cases
+// all you need is to define the following function in your file:
+// extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+
+// WARNING: keep the interface in C.
+
+#ifndef LLVM_FUZZER_INTERFACE_H
+#define LLVM_FUZZER_INTERFACE_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif  // __cplusplus
+
+// Mandatory user-provided target function.
+// Executes the code under test with [Data, Data+Size) as the input.
+// libFuzzer will invoke this function *many* times with different inputs.
+// Must return 0.
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+
+// Optional user-provided initialization function.
+// If provided, this function will be called by libFuzzer once at startup.
+// It may read and modify argc/argv.
+// Must return 0.
+int LLVMFuzzerInitialize(int *argc, char ***argv);
+
+// Optional user-provided custom mutator.
+// Mutates raw data in [Data, Data+Size) inplace.
+// Returns the new size, which is not greater than MaxSize.
+// Given the same Seed produces the same mutation.
+size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size, size_t MaxSize,
+                               unsigned int Seed);
+
+// Optional user-provided custom cross-over function.
+// Combines pieces of Data1 & Data2 together into Out.
+// Returns the new size, which is not greater than MaxOutSize.
+// Should produce the same mutation given the same Seed.
+size_t LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
+                                 const uint8_t *Data2, size_t Size2,
+                                 uint8_t *Out, size_t MaxOutSize,
+                                 unsigned int Seed);
+
+// Experimental, may go away in future.
+// libFuzzer-provided function to be used inside LLVMFuzzerTestOneInput.
+// Mutates raw data in [Data, Data+Size) inplace.
+// Returns the new size, which is not greater than MaxSize.
+size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif  // __cplusplus
+
+#endif  // LLVM_FUZZER_INTERFACE_H

test/fuzz_test/Fuzzer/FuzzerInternal.h

@@ -0,0 +1,182 @@
+//===- FuzzerInternal.h - Internal header for the Fuzzer --------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Define the main class fuzzer::Fuzzer and most functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_INTERNAL_H
+#define LLVM_FUZZER_INTERNAL_H
+
+#include "FuzzerDefs.h"
+#include "FuzzerExtFunctions.h"
+#include "FuzzerInterface.h"
+#include "FuzzerOptions.h"
+#include "FuzzerSHA1.h"
+#include "FuzzerValueBitMap.h"
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <climits>
+#include <cstdlib>
+#include <string.h>
+
+namespace fuzzer {
+
+using namespace std::chrono;
+
+class Fuzzer {
+public:
+
+  // Aggregates all available coverage measurements.
+  struct Coverage {
+    Coverage() { Reset(); }
+
+    void Reset() {
+      BlockCoverage = 0;
+      CallerCalleeCoverage = 0;
+      CounterBitmapBits = 0;
+      CounterBitmap.clear();
+      VPMap.Reset();
+    }
+
+    size_t BlockCoverage;
+    size_t CallerCalleeCoverage;
+    // Precalculated number of bits in CounterBitmap.
+    size_t CounterBitmapBits;
+    std::vector<uint8_t> CounterBitmap;
+    ValueBitMap VPMap;
+  };
+
+  Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
+         FuzzingOptions Options);
+  ~Fuzzer();
+  void Loop();
+  void MinimizeCrashLoop(const Unit &U);
+  void ShuffleAndMinimize(UnitVector *V);
+  void InitializeTraceState();
+  void RereadOutputCorpus(size_t MaxSize);
+
+  size_t secondsSinceProcessStartUp() {
+    return duration_cast<seconds>(system_clock::now() - ProcessStartTime)
+        .count();
+  }
+
+  bool TimedOut() {
+    return Options.MaxTotalTimeSec > 0 &&
+           secondsSinceProcessStartUp() >
+               static_cast<size_t>(Options.MaxTotalTimeSec);
+  }
+
+  size_t execPerSec() {
+    size_t Seconds = secondsSinceProcessStartUp();
+    return Seconds ? TotalNumberOfRuns / Seconds : 0;
+  }
+
+  size_t getTotalNumberOfRuns() { return TotalNumberOfRuns; }
+
+  static void StaticAlarmCallback();
+  static void StaticCrashSignalCallback();
+  static void StaticInterruptCallback();
+
+  void ExecuteCallback(const uint8_t *Data, size_t Size);
+  size_t RunOne(const uint8_t *Data, size_t Size);
+
+  // Merge Corpora[1:] into Corpora[0].
+  void Merge(const std::vector<std::string> &Corpora);
+  void CrashResistantMerge(const std::vector<std::string> &Args,
+                           const std::vector<std::string> &Corpora);
+  void CrashResistantMergeInternalStep(const std::string &ControlFilePath);
+  // Returns a subset of 'Extra' that adds coverage to 'Initial'.
+  UnitVector FindExtraUnits(const UnitVector &Initial, const UnitVector &Extra);
+  MutationDispatcher &GetMD() { return MD; }
+  void PrintFinalStats();
+  void SetMaxInputLen(size_t MaxInputLen);
+  void SetMaxMutationLen(size_t MaxMutationLen);
+  void RssLimitCallback();
+
+  // Public for tests.
+  void ResetCoverage();
+
+  bool InFuzzingThread() const { return IsMyThread; }
+  size_t GetCurrentUnitInFuzzingThead(const uint8_t **Data) const;
+  void TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
+                               bool DuringInitialCorpusExecution);
+
+  void HandleMalloc(size_t Size);
+
+private:
+  void AlarmCallback();
+  void CrashCallback();
+  void InterruptCallback();
+  void MutateAndTestOne();
+  void ReportNewCoverage(InputInfo *II, const Unit &U);
+  size_t RunOne(const Unit &U) { return RunOne(U.data(), U.size()); }
+  void WriteToOutputCorpus(const Unit &U);
+  void WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix);
+  void PrintStats(const char *Where, const char *End = "\n", size_t Units = 0);
+  void PrintStatusForNewUnit(const Unit &U);
+  void ShuffleCorpus(UnitVector *V);
+  void AddToCorpus(const Unit &U);
+  void CheckExitOnSrcPosOrItem();
+
+  // Trace-based fuzzing: we run a unit with some kind of tracing
+  // enabled and record potentially useful mutations. Then
+  // We apply these mutations one by one to the unit and run it again.
+
+  // Start tracing; forget all previously proposed mutations.
+  void StartTraceRecording();
+  // Stop tracing.
+  void StopTraceRecording();
+
+  void SetDeathCallback();
+  static void StaticDeathCallback();
+  void DumpCurrentUnit(const char *Prefix);
+  void DeathCallback();
+
+  void ResetEdgeCoverage();
+  void ResetCounters();
+  void PrepareCounters(Fuzzer::Coverage *C);
+  bool RecordMaxCoverage(Fuzzer::Coverage *C);
+
+  void AllocateCurrentUnitData();
+  uint8_t *CurrentUnitData = nullptr;
+  std::atomic<size_t> CurrentUnitSize;
+  uint8_t BaseSha1[kSHA1NumBytes];  // Checksum of the base unit.
+  bool RunningCB = false;
+
+  size_t TotalNumberOfRuns = 0;
+  size_t NumberOfNewUnitsAdded = 0;
+
+  bool HasMoreMallocsThanFrees = false;
+  size_t NumberOfLeakDetectionAttempts = 0;
+
+  UserCallback CB;
+  InputCorpus &Corpus;
+  MutationDispatcher &MD;
+  FuzzingOptions Options;
+
+  system_clock::time_point ProcessStartTime = system_clock::now();
+  system_clock::time_point UnitStartTime, UnitStopTime;
+  long TimeOfLongestUnitInSeconds = 0;
+  long EpochOfLastReadOfOutputCorpus = 0;
+
+  // Maximum recorded coverage.
+  Coverage MaxCoverage;
+
+  size_t MaxInputLen = 0;
+  size_t MaxMutationLen = 0;
+
+  // Need to know our own thread.
+  static thread_local bool IsMyThread;
+
+  bool InMergeMode = false;
+};
+
+}; // namespace fuzzer
+
+#endif // LLVM_FUZZER_INTERNAL_H

test/fuzz_test/Fuzzer/FuzzerLoop.cpp

@@ -0,0 +1,792 @@
+//===- FuzzerLoop.cpp - Fuzzer's main loop --------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Fuzzer's main loop.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCorpus.h"
+#include "FuzzerInternal.h"
+#include "FuzzerIO.h"
+#include "FuzzerMutate.h"
+#include "FuzzerRandom.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <cstring>
+#include <memory>
+#include <set>
+
+#if defined(__has_include)
+#if __has_include(<sanitizer / coverage_interface.h>)
+#include <sanitizer/coverage_interface.h>
+#endif
+#if __has_include(<sanitizer / lsan_interface.h>)
+#include <sanitizer/lsan_interface.h>
+#endif
+#endif
+
+#define NO_SANITIZE_MEMORY
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+#undef NO_SANITIZE_MEMORY
+#define NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
+#endif
+#endif
+
+namespace fuzzer {
+static const size_t kMaxUnitSizeToPrint = 256;
+
+thread_local bool Fuzzer::IsMyThread;
+
+static void MissingExternalApiFunction(const char *FnName) {
+  Printf("ERROR: %s is not defined. Exiting.\n"
+         "Did you use -fsanitize-coverage=... to build your code?\n",
+         FnName);
+  exit(1);
+}
+
+#define CHECK_EXTERNAL_FUNCTION(fn)                                            \
+  do {                                                                         \
+    if (!(EF->fn))                                                             \
+      MissingExternalApiFunction(#fn);                                         \
+  } while (false)
+
+// Only one Fuzzer per process.
+static Fuzzer *F;
+
+void Fuzzer::ResetEdgeCoverage() {
+  CHECK_EXTERNAL_FUNCTION(__sanitizer_reset_coverage);
+  EF->__sanitizer_reset_coverage();
+}
+
+void Fuzzer::ResetCounters() {
+  if (Options.UseCounters)
+    EF->__sanitizer_update_counter_bitset_and_clear_counters(0);
+}
+
+void Fuzzer::PrepareCounters(Fuzzer::Coverage *C) {
+  if (Options.UseCounters) {
+    size_t NumCounters = EF->__sanitizer_get_number_of_counters();
+    C->CounterBitmap.resize(NumCounters);
+  }
+}
+
+// Records data to a maximum coverage tracker. Returns true if additional
+// coverage was discovered.
+bool Fuzzer::RecordMaxCoverage(Fuzzer::Coverage *C) {
+  bool Res = false;
+
+  uint64_t NewBlockCoverage = EF->__sanitizer_get_total_unique_coverage();
+  if (NewBlockCoverage > C->BlockCoverage) {
+    Res = true;
+    C->BlockCoverage = NewBlockCoverage;
+  }
+
+  if (Options.UseIndirCalls &&
+      EF->__sanitizer_get_total_unique_caller_callee_pairs) {
+    uint64_t NewCallerCalleeCoverage =
+        EF->__sanitizer_get_total_unique_caller_callee_pairs();
+    if (NewCallerCalleeCoverage > C->CallerCalleeCoverage) {
+      Res = true;
+      C->CallerCalleeCoverage = NewCallerCalleeCoverage;
+    }
+  }
+
+  if (Options.UseCounters) {
+    uint64_t CounterDelta =
+        EF->__sanitizer_update_counter_bitset_and_clear_counters(
+            C->CounterBitmap.data());
+    if (CounterDelta > 0) {
+      Res = true;
+      C->CounterBitmapBits += CounterDelta;
+    }
+  }
+
+  return Res;
+}
+
+// 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(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() {
+    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;
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void MallocHook(const volatile void *ptr, size_t size) {
+  size_t N = AllocTracer.Mallocs++;
+  F->HandleMalloc(size);
+  if (int TraceLevel = AllocTracer.TraceLevel) {
+    Printf("MALLOC[%zd] %p %zd\n", N, ptr, size);
+    if (TraceLevel >= 2 && EF)
+      EF->__sanitizer_print_stack_trace();
+  }
+}
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void FreeHook(const volatile void *ptr) {
+  size_t N = AllocTracer.Frees++;
+  if (int TraceLevel = AllocTracer.TraceLevel) {
+    Printf("FREE[%zd]   %p\n", N, ptr);
+    if (TraceLevel >= 2 && EF)
+      EF->__sanitizer_print_stack_trace();
+  }
+}
+
+// Crash on a single malloc that exceeds the rss limit.
+void Fuzzer::HandleMalloc(size_t Size) {
+  if (!Options.RssLimitMb || (Size >> 20) < (size_t)Options.RssLimitMb)
+    return;
+  Printf("==%d== ERROR: libFuzzer: out-of-memory (malloc(%zd))\n", GetPid(),
+         Size);
+  Printf("   To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
+  if (EF->__sanitizer_print_stack_trace)
+    EF->__sanitizer_print_stack_trace();
+  DumpCurrentUnit("oom-");
+  Printf("SUMMARY: libFuzzer: out-of-memory\n");
+  PrintFinalStats();
+  _Exit(Options.ErrorExitCode); // Stop right now.
+}
+
+Fuzzer::Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
+               FuzzingOptions Options)
+    : CB(CB), Corpus(Corpus), MD(MD), Options(Options) {
+  SetDeathCallback();
+  InitializeTraceState();
+  assert(!F);
+  F = this;
+  TPC.ResetMaps();
+  ResetCoverage();
+  IsMyThread = true;
+  if (Options.DetectLeaks && EF->__sanitizer_install_malloc_and_free_hooks)
+    EF->__sanitizer_install_malloc_and_free_hooks(MallocHook, FreeHook);
+  TPC.SetUseCounters(Options.UseCounters);
+  TPC.SetUseValueProfile(Options.UseValueProfile);
+  TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
+
+  if (Options.Verbosity)
+    TPC.PrintModuleInfo();
+  if (!Options.OutputCorpus.empty() && Options.ReloadIntervalSec)
+    EpochOfLastReadOfOutputCorpus = GetEpoch(Options.OutputCorpus);
+  MaxInputLen = MaxMutationLen = Options.MaxLen;
+  AllocateCurrentUnitData();
+  CurrentUnitSize = 0;
+  memset(BaseSha1, 0, sizeof(BaseSha1));
+}
+
+Fuzzer::~Fuzzer() { }
+
+void Fuzzer::AllocateCurrentUnitData() {
+  if (CurrentUnitData || MaxInputLen == 0) return;
+  CurrentUnitData = new uint8_t[MaxInputLen];
+}
+
+void Fuzzer::SetDeathCallback() {
+  CHECK_EXTERNAL_FUNCTION(__sanitizer_set_death_callback);
+  EF->__sanitizer_set_death_callback(StaticDeathCallback);
+}
+
+void Fuzzer::StaticDeathCallback() {
+  assert(F);
+  F->DeathCallback();
+}
+
+static void WarnOnUnsuccessfullMerge(bool DoWarn) {
+  if (!DoWarn) return;
+  Printf(
+   "***\n"
+   "***\n"
+   "***\n"
+   "*** NOTE: merge did not succeed due to a failure on one of the inputs.\n"
+   "*** You will need to filter out crashes from the corpus, e.g. like this:\n"
+   "***   for f in WITH_CRASHES/*; do ./fuzzer $f && cp $f NO_CRASHES; done\n"
+   "*** Future versions may have crash-resistant merge, stay tuned.\n"
+   "***\n"
+   "***\n"
+   "***\n");
+}
+
+void Fuzzer::DumpCurrentUnit(const char *Prefix) {
+  WarnOnUnsuccessfullMerge(InMergeMode);
+  if (!CurrentUnitData) return;  // Happens when running individual inputs.
+  MD.PrintMutationSequence();
+  Printf("; base unit: %s\n", Sha1ToString(BaseSha1).c_str());
+  size_t UnitSize = CurrentUnitSize;
+  if (UnitSize <= kMaxUnitSizeToPrint) {
+    PrintHexArray(CurrentUnitData, UnitSize, "\n");
+    PrintASCII(CurrentUnitData, UnitSize, "\n");
+  }
+  WriteUnitToFileWithPrefix({CurrentUnitData, CurrentUnitData + UnitSize},
+                            Prefix);
+}
+
+NO_SANITIZE_MEMORY
+void Fuzzer::DeathCallback() {
+  DumpCurrentUnit("crash-");
+  PrintFinalStats();
+}
+
+void Fuzzer::StaticAlarmCallback() {
+  assert(F);
+  F->AlarmCallback();
+}
+
+void Fuzzer::StaticCrashSignalCallback() {
+  assert(F);
+  F->CrashCallback();
+}
+
+void Fuzzer::StaticInterruptCallback() {
+  assert(F);
+  F->InterruptCallback();
+}
+
+void Fuzzer::CrashCallback() {
+  Printf("==%lu== ERROR: libFuzzer: deadly signal\n", GetPid());
+  if (EF->__sanitizer_print_stack_trace)
+    EF->__sanitizer_print_stack_trace();
+  Printf("NOTE: libFuzzer has rudimentary signal handlers.\n"
+         "      Combine libFuzzer with AddressSanitizer or similar for better "
+         "crash reports.\n");
+  Printf("SUMMARY: libFuzzer: deadly signal\n");
+  DumpCurrentUnit("crash-");
+  PrintFinalStats();
+  exit(Options.ErrorExitCode);
+}
+
+void Fuzzer::InterruptCallback() {
+  Printf("==%lu== libFuzzer: run interrupted; exiting\n", GetPid());
+  PrintFinalStats();
+  _Exit(0);  // Stop right now, don't perform any at-exit actions.
+}
+
+NO_SANITIZE_MEMORY
+void Fuzzer::AlarmCallback() {
+  assert(Options.UnitTimeoutSec > 0);
+  if (!InFuzzingThread()) return;
+  if (!RunningCB)
+    return; // We have not started running units yet.
+  size_t Seconds =
+      duration_cast<seconds>(system_clock::now() - UnitStartTime).count();
+  if (Seconds == 0)
+    return;
+  if (Options.Verbosity >= 2)
+    Printf("AlarmCallback %zd\n", Seconds);
+  if (Seconds >= (size_t)Options.UnitTimeoutSec) {
+    Printf("ALARM: working on the last Unit for %zd seconds\n", Seconds);
+    Printf("       and the timeout value is %d (use -timeout=N to change)\n",
+           Options.UnitTimeoutSec);
+    DumpCurrentUnit("timeout-");
+    Printf("==%lu== ERROR: libFuzzer: timeout after %d seconds\n", GetPid(),
+           Seconds);
+    if (EF->__sanitizer_print_stack_trace)
+      EF->__sanitizer_print_stack_trace();
+    Printf("SUMMARY: libFuzzer: timeout\n");
+    PrintFinalStats();
+    _Exit(Options.TimeoutExitCode); // Stop right now.
+  }
+}
+
+void Fuzzer::RssLimitCallback() {
+  Printf(
+      "==%lu== ERROR: libFuzzer: out-of-memory (used: %zdMb; limit: %zdMb)\n",
+      GetPid(), GetPeakRSSMb(), Options.RssLimitMb);
+  Printf("   To change the out-of-memory limit use -rss_limit_mb=<N>\n\n");
+  if (EF->__sanitizer_print_memory_profile)
+    EF->__sanitizer_print_memory_profile(95);
+  DumpCurrentUnit("oom-");
+  Printf("SUMMARY: libFuzzer: out-of-memory\n");
+  PrintFinalStats();
+  _Exit(Options.ErrorExitCode); // Stop right now.
+}
+
+void Fuzzer::PrintStats(const char *Where, const char *End, size_t Units) {
+  size_t ExecPerSec = execPerSec();
+  if (Options.OutputCSV) {
+    static bool csvHeaderPrinted = false;
+    if (!csvHeaderPrinted) {
+      csvHeaderPrinted = true;
+      Printf("runs,block_cov,bits,cc_cov,corpus,execs_per_sec,tbms,reason\n");
+    }
+    Printf("%zd,%zd,%zd,%zd,%zd,%zd,%s\n", TotalNumberOfRuns,
+           MaxCoverage.BlockCoverage, MaxCoverage.CounterBitmapBits,
+           MaxCoverage.CallerCalleeCoverage, Corpus.size(), ExecPerSec, Where);
+  }
+
+  if (!Options.Verbosity)
+    return;
+  Printf("#%zd\t%s", TotalNumberOfRuns, Where);
+  if (MaxCoverage.BlockCoverage)
+    Printf(" cov: %zd", MaxCoverage.BlockCoverage);
+  if (size_t N = MaxCoverage.VPMap.GetNumBitsSinceLastMerge())
+    Printf(" vp: %zd", N);
+  if (size_t N = TPC.GetTotalPCCoverage())
+    Printf(" cov: %zd", N);
+  if (auto TB = MaxCoverage.CounterBitmapBits)
+    Printf(" bits: %zd", TB);
+  if (size_t N = Corpus.NumFeatures())
+    Printf( " ft: %zd", N);
+  if (MaxCoverage.CallerCalleeCoverage)
+    Printf(" indir: %zd", MaxCoverage.CallerCalleeCoverage);
+  if (!Corpus.empty()) {
+    Printf(" corp: %zd", Corpus.NumActiveUnits());
+    if (size_t N = Corpus.SizeInBytes()) {
+      if (N < (1<<14))
+        Printf("/%zdb", N);
+      else if (N < (1 << 24))
+        Printf("/%zdKb", N >> 10);
+      else
+        Printf("/%zdMb", N >> 20);
+    }
+  }
+  if (Units)
+    Printf(" units: %zd", Units);
+
+  Printf(" exec/s: %zd", ExecPerSec);
+  Printf(" rss: %zdMb", GetPeakRSSMb());
+  Printf("%s", End);
+}
+
+void Fuzzer::PrintFinalStats() {
+  if (Options.PrintCoverage)
+    TPC.PrintCoverage();
+  if (Options.DumpCoverage)
+    TPC.DumpCoverage();
+  if (Options.PrintCorpusStats)
+    Corpus.PrintStats();
+  if (!Options.PrintFinalStats) return;
+  size_t ExecPerSec = execPerSec();
+  Printf("stat::number_of_executed_units: %zd\n", TotalNumberOfRuns);
+  Printf("stat::average_exec_per_sec:     %zd\n", ExecPerSec);
+  Printf("stat::new_units_added:          %zd\n", NumberOfNewUnitsAdded);
+  Printf("stat::slowest_unit_time_sec:    %zd\n", TimeOfLongestUnitInSeconds);
+  Printf("stat::peak_rss_mb:              %zd\n", GetPeakRSSMb());
+}
+
+void Fuzzer::SetMaxInputLen(size_t MaxInputLen) {
+  assert(this->MaxInputLen == 0); // Can only reset MaxInputLen from 0 to non-0.
+  assert(MaxInputLen);
+  this->MaxInputLen = MaxInputLen;
+  this->MaxMutationLen = MaxInputLen;
+  AllocateCurrentUnitData();
+  Printf("INFO: -max_len is not provided, using %zd\n", MaxInputLen);
+}
+
+void Fuzzer::SetMaxMutationLen(size_t MaxMutationLen) {
+  assert(MaxMutationLen && MaxMutationLen <= MaxInputLen);
+  this->MaxMutationLen = MaxMutationLen;
+}
+
+void Fuzzer::CheckExitOnSrcPosOrItem() {
+  if (!Options.ExitOnSrcPos.empty()) {
+    static auto *PCsSet = new std::set<uintptr_t>;
+    for (size_t i = 1, N = TPC.GetNumPCs(); i < N; i++) {
+      uintptr_t PC = TPC.GetPC(i);
+      if (!PC) continue;
+      if (!PCsSet->insert(PC).second) continue;
+      std::string Descr = DescribePC("%L", PC);
+      if (Descr.find(Options.ExitOnSrcPos) != std::string::npos) {
+        Printf("INFO: found line matching '%s', exiting.\n",
+               Options.ExitOnSrcPos.c_str());
+        _Exit(0);
+      }
+    }
+  }
+  if (!Options.ExitOnItem.empty()) {
+    if (Corpus.HasUnit(Options.ExitOnItem)) {
+      Printf("INFO: found item with checksum '%s', exiting.\n",
+             Options.ExitOnItem.c_str());
+      _Exit(0);
+    }
+  }
+}
+
+void Fuzzer::RereadOutputCorpus(size_t MaxSize) {
+  if (Options.OutputCorpus.empty() || !Options.ReloadIntervalSec) return;
+  std::vector<Unit> AdditionalCorpus;
+  ReadDirToVectorOfUnits(Options.OutputCorpus.c_str(), &AdditionalCorpus,
+                         &EpochOfLastReadOfOutputCorpus, MaxSize,
+                         /*ExitOnError*/ false);
+  if (Options.Verbosity >= 2)
+    Printf("Reload: read %zd new units.\n", AdditionalCorpus.size());
+  bool Reloaded = false;
+  for (auto &U : AdditionalCorpus) {
+    if (U.size() > MaxSize)
+      U.resize(MaxSize);
+    if (!Corpus.HasUnit(U)) {
+      if (size_t NumFeatures = RunOne(U)) {
+        CheckExitOnSrcPosOrItem();
+        Corpus.AddToCorpus(U, NumFeatures);
+        Reloaded = true;
+      }
+    }
+  }
+  if (Reloaded)
+    PrintStats("RELOAD");
+}
+
+void Fuzzer::ShuffleCorpus(UnitVector *V) {
+  std::random_shuffle(V->begin(), V->end(), MD.GetRand());
+  if (Options.PreferSmall)
+    std::stable_sort(V->begin(), V->end(), [](const Unit &A, const Unit &B) {
+      return A.size() < B.size();
+    });
+}
+
+void Fuzzer::ShuffleAndMinimize(UnitVector *InitialCorpus) {
+  Printf("#0\tREAD units: %zd\n", InitialCorpus->size());
+  if (Options.ShuffleAtStartUp)
+    ShuffleCorpus(InitialCorpus);
+
+  // Test the callback with empty input and never try it again.
+  uint8_t dummy;
+  ExecuteCallback(&dummy, 0);
+
+  for (const auto &U : *InitialCorpus) {
+    if (size_t NumFeatures = RunOne(U)) {
+      CheckExitOnSrcPosOrItem();
+      Corpus.AddToCorpus(U, NumFeatures);
+      if (Options.Verbosity >= 2)
+        Printf("NEW0: %zd L %zd\n", MaxCoverage.BlockCoverage, U.size());
+    }
+    TryDetectingAMemoryLeak(U.data(), U.size(),
+                            /*DuringInitialCorpusExecution*/ true);
+  }
+  PrintStats("INITED");
+  if (Corpus.empty()) {
+    Printf("ERROR: no interesting inputs were found. "
+           "Is the code instrumented for coverage? Exiting.\n");
+    exit(1);
+  }
+}
+
+size_t Fuzzer::RunOne(const uint8_t *Data, size_t Size) {
+  if (!Size) return 0;
+  TotalNumberOfRuns++;
+
+  ExecuteCallback(Data, Size);
+
+  size_t Res = 0;
+  if (size_t NumFeatures = TPC.CollectFeatures([&](size_t Feature) -> bool {
+        return Corpus.AddFeature(Feature, Size, Options.Shrink);
+      }))
+    Res = NumFeatures;
+
+  if (!TPC.UsingTracePcGuard()) {
+    if (TPC.UpdateValueProfileMap(&MaxCoverage.VPMap))
+      Res = 1;
+    if (!Res && RecordMaxCoverage(&MaxCoverage))
+      Res = 1;
+  }
+
+  auto TimeOfUnit =
+      duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
+  if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)) &&
+      secondsSinceProcessStartUp() >= 2)
+    PrintStats("pulse ");
+  if (TimeOfUnit > TimeOfLongestUnitInSeconds * 1.1 &&
+      TimeOfUnit >= Options.ReportSlowUnits) {
+    TimeOfLongestUnitInSeconds = TimeOfUnit;
+    Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
+    WriteUnitToFileWithPrefix({Data, Data + Size}, "slow-unit-");
+  }
+  return Res;
+}
+
+size_t Fuzzer::GetCurrentUnitInFuzzingThead(const uint8_t **Data) const {
+  assert(InFuzzingThread());
+  *Data = CurrentUnitData;
+  return CurrentUnitSize;
+}
+
+void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
+  assert(InFuzzingThread());
+  // We copy the contents of Unit into a separate heap buffer
+  // so that we reliably find buffer overflows in it.
+  uint8_t *DataCopy = new uint8_t[Size];
+  memcpy(DataCopy, Data, Size);
+  if (CurrentUnitData && CurrentUnitData != Data)
+    memcpy(CurrentUnitData, Data, Size);
+  CurrentUnitSize = Size;
+  AllocTracer.Start(Options.TraceMalloc);
+  UnitStartTime = system_clock::now();
+  ResetCounters();  // Reset coverage right before the callback.
+  TPC.ResetMaps();
+  RunningCB = true;
+  int Res = CB(DataCopy, Size);
+  RunningCB = false;
+  UnitStopTime = system_clock::now();
+  (void)Res;
+  assert(Res == 0);
+  HasMoreMallocsThanFrees = AllocTracer.Stop();
+  CurrentUnitSize = 0;
+  delete[] DataCopy;
+}
+
+void Fuzzer::WriteToOutputCorpus(const Unit &U) {
+  if (Options.OnlyASCII)
+    assert(IsASCII(U));
+  if (Options.OutputCorpus.empty())
+    return;
+  std::string Path = DirPlusFile(Options.OutputCorpus, Hash(U));
+  WriteToFile(U, Path);
+  if (Options.Verbosity >= 2)
+    Printf("Written to %s\n", Path.c_str());
+}
+
+void Fuzzer::WriteUnitToFileWithPrefix(const Unit &U, const char *Prefix) {
+  if (!Options.SaveArtifacts)
+    return;
+  std::string Path = Options.ArtifactPrefix + Prefix + Hash(U);
+  if (!Options.ExactArtifactPath.empty())
+    Path = Options.ExactArtifactPath; // Overrides ArtifactPrefix.
+  WriteToFile(U, Path);
+  Printf("artifact_prefix='%s'; Test unit written to %s\n",
+         Options.ArtifactPrefix.c_str(), Path.c_str());
+  if (U.size() <= kMaxUnitSizeToPrint)
+    Printf("Base64: %s\n", Base64(U).c_str());
+}
+
+void Fuzzer::PrintStatusForNewUnit(const Unit &U) {
+  if (!Options.PrintNEW)
+    return;
+  PrintStats("NEW   ", "");
+  if (Options.Verbosity) {
+    Printf(" L: %zd ", U.size());
+    MD.PrintMutationSequence();
+    Printf("\n");
+  }
+}
+
+void Fuzzer::ReportNewCoverage(InputInfo *II, const Unit &U) {
+  II->NumSuccessfullMutations++;
+  MD.RecordSuccessfulMutationSequence();
+  PrintStatusForNewUnit(U);
+  WriteToOutputCorpus(U);
+  NumberOfNewUnitsAdded++;
+  TPC.PrintNewPCs();
+}
+
+// Finds minimal number of units in 'Extra' that add coverage to 'Initial'.
+// We do it by actually executing the units, sometimes more than once,
+// because we may be using different coverage-like signals and the only
+// common thing between them is that we can say "this unit found new stuff".
+UnitVector Fuzzer::FindExtraUnits(const UnitVector &Initial,
+                                  const UnitVector &Extra) {
+  UnitVector Res = Extra;
+  UnitVector Tmp;
+  size_t OldSize = Res.size();
+  for (int Iter = 0; Iter < 10; Iter++) {
+    ShuffleCorpus(&Res);
+    TPC.ResetMaps();
+    Corpus.ResetFeatureSet();
+    ResetCoverage();
+
+    for (auto &U : Initial) {
+      TPC.ResetMaps();
+      RunOne(U);
+    }
+
+    Tmp.clear();
+    for (auto &U : Res) {
+      TPC.ResetMaps();
+      if (RunOne(U))
+        Tmp.push_back(U);
+    }
+
+    char Stat[7] = "MIN   ";
+    Stat[3] = '0' + Iter;
+    PrintStats(Stat, "\n", Tmp.size());
+
+    size_t NewSize = Tmp.size();
+    assert(NewSize <= OldSize);
+    Res.swap(Tmp);
+
+    if (NewSize + 5 >= OldSize)
+      break;
+    OldSize = NewSize;
+  }
+  return Res;
+}
+
+void Fuzzer::Merge(const std::vector<std::string> &Corpora) {
+  if (Corpora.size() <= 1) {
+    Printf("Merge requires two or more corpus dirs\n");
+    return;
+  }
+  InMergeMode = true;
+  std::vector<std::string> ExtraCorpora(Corpora.begin() + 1, Corpora.end());
+
+  assert(MaxInputLen > 0);
+  UnitVector Initial, Extra;
+  ReadDirToVectorOfUnits(Corpora[0].c_str(), &Initial, nullptr, MaxInputLen,
+                         true);
+  for (auto &C : ExtraCorpora)
+    ReadDirToVectorOfUnits(C.c_str(), &Extra, nullptr, MaxInputLen, true);
+
+  if (!Initial.empty()) {
+    Printf("=== Minimizing the initial corpus of %zd units\n", Initial.size());
+    Initial = FindExtraUnits({}, Initial);
+  }
+
+  Printf("=== Merging extra %zd units\n", Extra.size());
+  auto Res = FindExtraUnits(Initial, Extra);
+
+  for (auto &U: Res)
+    WriteToOutputCorpus(U);
+
+  Printf("=== Merge: written %zd units\n", Res.size());
+}
+
+// Tries detecting a memory leak on the particular input that we have just
+// executed before calling this function.
+void Fuzzer::TryDetectingAMemoryLeak(const uint8_t *Data, size_t Size,
+                                     bool DuringInitialCorpusExecution) {
+  if (!HasMoreMallocsThanFrees) return;  // mallocs==frees, a leak is unlikely.
+  if (!Options.DetectLeaks) return;
+  if (!&(EF->__lsan_enable) || !&(EF->__lsan_disable) ||
+      !(EF->__lsan_do_recoverable_leak_check))
+    return;  // No lsan.
+  // Run the target once again, but with lsan disabled so that if there is
+  // a real leak we do not report it twice.
+  EF->__lsan_disable();
+  ExecuteCallback(Data, Size);
+  EF->__lsan_enable();
+  if (!HasMoreMallocsThanFrees) return;  // a leak is unlikely.
+  if (NumberOfLeakDetectionAttempts++ > 1000) {
+    Options.DetectLeaks = false;
+    Printf("INFO: libFuzzer disabled leak detection after every mutation.\n"
+           "      Most likely the target function accumulates allocated\n"
+           "      memory in a global state w/o actually leaking it.\n"
+           "      You may try running this binary with -trace_malloc=[12]"
+           "      to get a trace of mallocs and frees.\n"
+           "      If LeakSanitizer is enabled in this process it will still\n"
+           "      run on the process shutdown.\n");
+    return;
+  }
+  // Now perform the actual lsan pass. This is expensive and we must ensure
+  // we don't call it too often.
+  if (EF->__lsan_do_recoverable_leak_check()) { // Leak is found, report it.
+    if (DuringInitialCorpusExecution)
+      Printf("\nINFO: a leak has been found in the initial corpus.\n\n");
+    Printf("INFO: to ignore leaks on libFuzzer side use -detect_leaks=0.\n\n");
+    CurrentUnitSize = Size;
+    DumpCurrentUnit("leak-");
+    PrintFinalStats();
+    _Exit(Options.ErrorExitCode);  // not exit() to disable lsan further on.
+  }
+}
+
+void Fuzzer::MutateAndTestOne() {
+  MD.StartMutationSequence();
+
+  auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
+  const auto &U = II.U;
+  memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
+  assert(CurrentUnitData);
+  size_t Size = U.size();
+  assert(Size <= MaxInputLen && "Oversized Unit");
+  memcpy(CurrentUnitData, U.data(), Size);
+
+  assert(MaxMutationLen > 0);
+
+  for (int i = 0; i < Options.MutateDepth; i++) {
+    if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+      break;
+    size_t NewSize = 0;
+    NewSize = MD.Mutate(CurrentUnitData, Size, MaxMutationLen);
+    assert(NewSize > 0 && "Mutator returned empty unit");
+    assert(NewSize <= MaxMutationLen && "Mutator return overisized unit");
+    Size = NewSize;
+    if (i == 0)
+      StartTraceRecording();
+    II.NumExecutedMutations++;
+    if (size_t NumFeatures = RunOne(CurrentUnitData, Size)) {
+      Corpus.AddToCorpus({CurrentUnitData, CurrentUnitData + Size}, NumFeatures,
+                         /*MayDeleteFile=*/true);
+      ReportNewCoverage(&II, {CurrentUnitData, CurrentUnitData + Size});
+      CheckExitOnSrcPosOrItem();
+    }
+    StopTraceRecording();
+    TryDetectingAMemoryLeak(CurrentUnitData, Size,
+                            /*DuringInitialCorpusExecution*/ false);
+  }
+}
+
+void Fuzzer::ResetCoverage() {
+  ResetEdgeCoverage();
+  MaxCoverage.Reset();
+  PrepareCounters(&MaxCoverage);
+}
+
+void Fuzzer::Loop() {
+  system_clock::time_point LastCorpusReload = system_clock::now();
+  if (Options.DoCrossOver)
+    MD.SetCorpus(&Corpus);
+  while (true) {
+    auto Now = system_clock::now();
+    if (duration_cast<seconds>(Now - LastCorpusReload).count() >=
+        Options.ReloadIntervalSec) {
+      RereadOutputCorpus(MaxInputLen);
+      LastCorpusReload = system_clock::now();
+    }
+    if (TotalNumberOfRuns >= Options.MaxNumberOfRuns)
+      break;
+    if (TimedOut()) break;
+    // Perform several mutations and runs.
+    MutateAndTestOne();
+  }
+
+  PrintStats("DONE  ", "\n");
+  MD.PrintRecommendedDictionary();
+}
+
+void Fuzzer::MinimizeCrashLoop(const Unit &U) {
+  if (U.size() <= 2) return;
+  while (!TimedOut() && TotalNumberOfRuns < Options.MaxNumberOfRuns) {
+    MD.StartMutationSequence();
+    memcpy(CurrentUnitData, U.data(), U.size());
+    for (int i = 0; i < Options.MutateDepth; i++) {
+      size_t NewSize = MD.Mutate(CurrentUnitData, U.size(), MaxMutationLen);
+      assert(NewSize > 0 && NewSize <= MaxMutationLen);
+      RunOne(CurrentUnitData, NewSize);
+      TryDetectingAMemoryLeak(CurrentUnitData, NewSize,
+                              /*DuringInitialCorpusExecution*/ false);
+    }
+  }
+}
+
+} // namespace fuzzer
+
+extern "C" {
+
+size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+  assert(fuzzer::F);
+  return fuzzer::F->GetMD().DefaultMutate(Data, Size, MaxSize);
+}
+}  // extern "C"

test/fuzz_test/Fuzzer/FuzzerMain.cpp

@@ -0,0 +1,21 @@
+//===- FuzzerMain.cpp - main() function and flags -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// main() and flags.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerDefs.h"
+
+extern "C" {
+// This function should be defined by the user.
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+}  // extern "C"
+
+int main(int argc, char **argv) {
+  return fuzzer::FuzzerDriver(&argc, &argv, LLVMFuzzerTestOneInput);
+}

test/fuzz_test/Fuzzer/FuzzerMerge.cpp

@@ -0,0 +1,261 @@
+//===- FuzzerMerge.cpp - merging corpora ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Merging corpora.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerInternal.h"
+#include "FuzzerIO.h"
+#include "FuzzerMerge.h"
+#include "FuzzerTracePC.h"
+#include "FuzzerUtil.h"
+
+#include <fstream>
+#include <iterator>
+#include <sstream>
+
+namespace fuzzer {
+
+bool Merger::Parse(const std::string &Str, bool ParseCoverage) {
+  std::istringstream SS(Str);
+  return Parse(SS, ParseCoverage);
+}
+
+void Merger::ParseOrExit(std::istream &IS, bool ParseCoverage) {
+  if (!Parse(IS, ParseCoverage)) {
+    Printf("MERGE: failed to parse the control file (unexpected error)\n");
+    exit(1);
+  }
+}
+
+// The control file example:
+//
+// 3 # The number of inputs
+// 1 # The number of inputs in the first corpus, <= the previous number
+// file0
+// file1
+// file2  # One file name per line.
+// STARTED 0 123  # FileID, file size
+// DONE 0 1 4 6 8  # FileID COV1 COV2 ...
+// STARTED 1 456  # If DONE is missing, the input crashed while processing.
+// STARTED 2 567
+// DONE 2 8 9
+bool Merger::Parse(std::istream &IS, bool ParseCoverage) {
+  LastFailure.clear();
+  std::string Line;
+
+  // Parse NumFiles.
+  if (!std::getline(IS, Line, '\n')) return false;
+  std::istringstream L1(Line);
+  size_t NumFiles = 0;
+  L1 >> NumFiles;
+  if (NumFiles == 0 || NumFiles > 10000000) return false;
+
+  // Parse NumFilesInFirstCorpus.
+  if (!std::getline(IS, Line, '\n')) return false;
+  std::istringstream L2(Line);
+  NumFilesInFirstCorpus = NumFiles + 1;
+  L2 >> NumFilesInFirstCorpus;
+  if (NumFilesInFirstCorpus > NumFiles) return false;
+
+  // Parse file names.
+  Files.resize(NumFiles);
+  for (size_t i = 0; i < NumFiles; i++)
+    if (!std::getline(IS, Files[i].Name, '\n'))
+      return false;
+
+  // Parse STARTED and DONE lines.
+  size_t ExpectedStartMarker = 0;
+  const size_t kInvalidStartMarker = -1;
+  size_t LastSeenStartMarker = kInvalidStartMarker;
+  while (std::getline(IS, Line, '\n')) {
+    std::istringstream ISS1(Line);
+    std::string Marker;
+    size_t N;
+    ISS1 >> Marker;
+    ISS1 >> N;
+    if (Marker == "STARTED") {
+      // STARTED FILE_ID FILE_SIZE
+      if (ExpectedStartMarker != N)
+        return false;
+      ISS1 >> Files[ExpectedStartMarker].Size;
+      LastSeenStartMarker = ExpectedStartMarker;
+      assert(ExpectedStartMarker < Files.size());
+      ExpectedStartMarker++;
+    } else if (Marker == "DONE") {
+      // DONE FILE_SIZE COV1 COV2 COV3 ...
+      size_t CurrentFileIdx = N;
+      if (CurrentFileIdx != LastSeenStartMarker)
+        return false;
+      LastSeenStartMarker = kInvalidStartMarker;
+      if (ParseCoverage) {
+        auto &V = Files[CurrentFileIdx].Features;
+        V.clear();
+        while (ISS1 >> std::hex >> N)
+          V.push_back(N);
+        std::sort(V.begin(), V.end());
+      }
+    } else {
+      return false;
+    }
+  }
+  if (LastSeenStartMarker != kInvalidStartMarker)
+    LastFailure = Files[LastSeenStartMarker].Name;
+
+  FirstNotProcessedFile = ExpectedStartMarker;
+  return true;
+}
+
+// Decides which files need to be merged (add thost to NewFiles).
+// Returns the number of new features added.
+size_t Merger::Merge(std::vector<std::string> *NewFiles) {
+  NewFiles->clear();
+  assert(NumFilesInFirstCorpus <= Files.size());
+  std::set<uint32_t> AllFeatures;
+
+  // What features are in the initial corpus?
+  for (size_t i = 0; i < NumFilesInFirstCorpus; i++) {
+    auto &Cur = Files[i].Features;
+    AllFeatures.insert(Cur.begin(), Cur.end());
+  }
+  size_t InitialNumFeatures = AllFeatures.size();
+
+  // Remove all features that we already know from all other inputs.
+  for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
+    auto &Cur = Files[i].Features;
+    std::vector<uint32_t> Tmp;
+    std::set_difference(Cur.begin(), Cur.end(), AllFeatures.begin(),
+                        AllFeatures.end(), std::inserter(Tmp, Tmp.begin()));
+    Cur.swap(Tmp);
+  }
+
+  // Sort. Give preference to
+  //   * smaller files
+  //   * files with more features.
+  std::sort(Files.begin() + NumFilesInFirstCorpus, Files.end(),
+            [&](const MergeFileInfo &a, const MergeFileInfo &b) -> bool {
+              if (a.Size != b.Size)
+                return a.Size < b.Size;
+              return a.Features.size() > b.Features.size();
+            });
+
+  // One greedy pass: add the file's features to AllFeatures.
+  // If new features were added, add this file to NewFiles.
+  for (size_t i = NumFilesInFirstCorpus; i < Files.size(); i++) {
+    auto &Cur = Files[i].Features;
+    // Printf("%s -> sz %zd ft %zd\n", Files[i].Name.c_str(),
+    //       Files[i].Size, Cur.size());
+    size_t OldSize = AllFeatures.size();
+    AllFeatures.insert(Cur.begin(), Cur.end());
+    if (AllFeatures.size() > OldSize)
+      NewFiles->push_back(Files[i].Name);
+  }
+  return AllFeatures.size() - InitialNumFeatures;
+}
+
+// Inner process. May crash if the target crashes.
+void Fuzzer::CrashResistantMergeInternalStep(const std::string &CFPath) {
+  Printf("MERGE-INNER: using the control file '%s'\n", CFPath.c_str());
+  Merger M;
+  std::ifstream IF(CFPath);
+  M.ParseOrExit(IF, false);
+  IF.close();
+  if (!M.LastFailure.empty())
+    Printf("MERGE-INNER: '%s' caused a failure at the previous merge step\n",
+           M.LastFailure.c_str());
+
+  Printf("MERGE-INNER: %zd total files;"
+         " %zd processed earlier; will process %zd files now\n",
+         M.Files.size(), M.FirstNotProcessedFile,
+         M.Files.size() - M.FirstNotProcessedFile);
+
+  std::ofstream OF(CFPath, std::ofstream::out | std::ofstream::app);
+  for (size_t i = M.FirstNotProcessedFile; i < M.Files.size(); i++) {
+    auto U = FileToVector(M.Files[i].Name);
+    if (U.size() > MaxInputLen) {
+      U.resize(MaxInputLen);
+      U.shrink_to_fit();
+    }
+    std::ostringstream StartedLine;
+    // Write the pre-run marker.
+    OF << "STARTED " << std::dec << i << " " << U.size() << "\n";
+    OF.flush();  // Flush is important since ExecuteCommand may crash.
+    // Run.
+    TPC.ResetMaps();
+    ExecuteCallback(U.data(), U.size());
+    // Collect coverage.
+    std::set<size_t> Features;
+    TPC.CollectFeatures([&](size_t Feature) -> bool {
+      Features.insert(Feature);
+      return true;
+    });
+    // Show stats.
+    TotalNumberOfRuns++;
+    if (!(TotalNumberOfRuns & (TotalNumberOfRuns - 1)))
+      PrintStats("pulse ");
+    // Write the post-run marker and the coverage.
+    OF << "DONE " << i;
+    for (size_t F : Features)
+      OF << " " << std::hex << F;
+    OF << "\n";
+  }
+}
+
+// Outer process. Does not call the target code and thus sohuld not fail.
+void Fuzzer::CrashResistantMerge(const std::vector<std::string> &Args,
+                                 const std::vector<std::string> &Corpora) {
+  if (Corpora.size() <= 1) {
+    Printf("Merge requires two or more corpus dirs\n");
+    return;
+  }
+  std::vector<std::string> AllFiles;
+  ListFilesInDirRecursive(Corpora[0], nullptr, &AllFiles, /*TopDir*/true);
+  size_t NumFilesInFirstCorpus = AllFiles.size();
+  for (size_t i = 1; i < Corpora.size(); i++)
+    ListFilesInDirRecursive(Corpora[i], nullptr, &AllFiles, /*TopDir*/true);
+  Printf("MERGE-OUTER: %zd files, %zd in the initial corpus\n",
+         AllFiles.size(), NumFilesInFirstCorpus);
+  std::string CFPath =
+      "libFuzzerTemp." + std::to_string(GetPid()) + ".txt";
+  // Write the control file.
+  RemoveFile(CFPath);
+  std::ofstream ControlFile(CFPath);
+  ControlFile << AllFiles.size() << "\n";
+  ControlFile << NumFilesInFirstCorpus << "\n";
+  for (auto &Path: AllFiles)
+    ControlFile << Path << "\n";
+  ControlFile.close();
+
+  // Execute the inner process untill it passes.
+  // Every inner process should execute at least one input.
+  std::string BaseCmd = CloneArgsWithoutX(Args, "keep-all-flags");
+  for (size_t i = 1; i <= AllFiles.size(); i++) {
+    Printf("MERGE-OUTER: attempt %zd\n", i);
+    auto ExitCode =
+        ExecuteCommand(BaseCmd + " -merge_control_file=" + CFPath);
+    if (!ExitCode) {
+      Printf("MERGE-OUTER: succesfull in %zd attempt(s)\n", i);
+      break;
+    }
+  }
+  // Read the control file and do the merge.
+  Merger M;
+  std::ifstream IF(CFPath);
+  M.ParseOrExit(IF, true);
+  IF.close();
+  std::vector<std::string> NewFiles;
+  size_t NumNewFeatures = M.Merge(&NewFiles);
+  Printf("MERGE-OUTER: %zd new files with %zd new features added\n",
+         NewFiles.size(), NumNewFeatures);
+  for (auto &F: NewFiles)
+    WriteToOutputCorpus(FileToVector(F));
+  // We are done, delete the control file.
+  RemoveFile(CFPath);
+}
+
+} // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerMerge.h

@@ -0,0 +1,70 @@
+//===- FuzzerMerge.h - merging corpa ----------------------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Merging Corpora.
+//
+// The task:
+//   Take the existing corpus (possibly empty) and merge new inputs into
+//   it so that only inputs with new coverage ('features') are added.
+//   The process should tolerate the crashes, OOMs, leaks, etc.
+//
+// Algorithm:
+//   The outter process collects the set of files and writes their names
+//   into a temporary "control" file, then repeatedly launches the inner
+//   process until all inputs are processed.
+//   The outer process does not actually execute the target code.
+//
+//   The inner process reads the control file and sees a) list of all the inputs
+//   and b) the last processed input. Then it starts processing the inputs one
+//   by one. Before processing every input it writes one line to control file:
+//   STARTED INPUT_ID INPUT_SIZE
+//   After processing an input it write another line:
+//   DONE INPUT_ID Feature1 Feature2 Feature3 ...
+//   If a crash happens while processing an input the last line in the control
+//   file will be "STARTED INPUT_ID" and so the next process will know
+//   where to resume.
+//
+//   Once all inputs are processed by the innner process(es) the outer process
+//   reads the control files and does the merge based entirely on the contents
+//   of control file.
+//   It uses a single pass greedy algorithm choosing first the smallest inputs
+//   within the same size the inputs that have more new features.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_MERGE_H
+#define LLVM_FUZZER_MERGE_H
+
+#include "FuzzerDefs.h"
+
+#include <istream>
+#include <set>
+
+namespace fuzzer {
+
+struct MergeFileInfo {
+  std::string Name;
+  size_t Size = 0;
+  std::vector<uint32_t> Features;
+};
+
+struct Merger {
+  std::vector<MergeFileInfo> Files;
+  size_t NumFilesInFirstCorpus = 0;
+  size_t FirstNotProcessedFile = 0;
+  std::string LastFailure;
+
+  bool Parse(std::istream &IS, bool ParseCoverage);
+  bool Parse(const std::string &Str, bool ParseCoverage);
+  void ParseOrExit(std::istream &IS, bool ParseCoverage);
+  size_t Merge(std::vector<std::string> *NewFiles);
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_MERGE_H

test/fuzz_test/Fuzzer/FuzzerMutate.cpp

@@ -0,0 +1,527 @@
+//===- FuzzerMutate.cpp - Mutate a test input -----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Mutate a test input.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCorpus.h"
+#include "FuzzerDefs.h"
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include "FuzzerMutate.h"
+#include "FuzzerOptions.h"
+
+namespace fuzzer {
+
+const size_t Dictionary::kMaxDictSize;
+
+static void PrintASCII(const Word &W, const char *PrintAfter) {
+  PrintASCII(W.data(), W.size(), PrintAfter);
+}
+
+MutationDispatcher::MutationDispatcher(Random &Rand,
+                                       const FuzzingOptions &Options)
+    : Rand(Rand), Options(Options) {
+  DefaultMutators.insert(
+      DefaultMutators.begin(),
+      {
+          {&MutationDispatcher::Mutate_EraseBytes, "EraseBytes"},
+          {&MutationDispatcher::Mutate_InsertByte, "InsertByte"},
+          {&MutationDispatcher::Mutate_InsertRepeatedBytes,
+           "InsertRepeatedBytes"},
+          {&MutationDispatcher::Mutate_ChangeByte, "ChangeByte"},
+          {&MutationDispatcher::Mutate_ChangeBit, "ChangeBit"},
+          {&MutationDispatcher::Mutate_ShuffleBytes, "ShuffleBytes"},
+          {&MutationDispatcher::Mutate_ChangeASCIIInteger, "ChangeASCIIInt"},
+          {&MutationDispatcher::Mutate_ChangeBinaryInteger, "ChangeBinInt"},
+          {&MutationDispatcher::Mutate_CopyPart, "CopyPart"},
+          {&MutationDispatcher::Mutate_CrossOver, "CrossOver"},
+          {&MutationDispatcher::Mutate_AddWordFromManualDictionary,
+           "ManualDict"},
+          {&MutationDispatcher::Mutate_AddWordFromTemporaryAutoDictionary,
+           "TempAutoDict"},
+          {&MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary,
+           "PersAutoDict"},
+      });
+  if(Options.UseCmp)
+    DefaultMutators.push_back(
+        {&MutationDispatcher::Mutate_AddWordFromTORC, "CMP"});
+
+  if (EF->LLVMFuzzerCustomMutator)
+    Mutators.push_back({&MutationDispatcher::Mutate_Custom, "Custom"});
+  else
+    Mutators = DefaultMutators;
+
+  if (EF->LLVMFuzzerCustomCrossOver)
+    Mutators.push_back(
+        {&MutationDispatcher::Mutate_CustomCrossOver, "CustomCrossOver"});
+}
+
+static char RandCh(Random &Rand) {
+  if (Rand.RandBool()) return Rand(256);
+  const char *Special = "!*'();:@&=+$,/?%#[]012Az-`~.\xff\x00";
+  return Special[Rand(sizeof(Special) - 1)];
+}
+
+size_t MutationDispatcher::Mutate_Custom(uint8_t *Data, size_t Size,
+                                         size_t MaxSize) {
+  return EF->LLVMFuzzerCustomMutator(Data, Size, MaxSize, Rand.Rand());
+}
+
+size_t MutationDispatcher::Mutate_CustomCrossOver(uint8_t *Data, size_t Size,
+                                                  size_t MaxSize) {
+  if (!Corpus || Corpus->size() < 2 || Size == 0)
+    return 0;
+  size_t Idx = Rand(Corpus->size());
+  const Unit &Other = (*Corpus)[Idx];
+  if (Other.empty())
+    return 0;
+  MutateInPlaceHere.resize(MaxSize);
+  auto &U = MutateInPlaceHere;
+  size_t NewSize = EF->LLVMFuzzerCustomCrossOver(
+      Data, Size, Other.data(), Other.size(), U.data(), U.size(), Rand.Rand());
+  if (!NewSize)
+    return 0;
+  assert(NewSize <= MaxSize && "CustomCrossOver returned overisized unit");
+  memcpy(Data, U.data(), NewSize);
+  return NewSize;
+}
+
+size_t MutationDispatcher::Mutate_ShuffleBytes(uint8_t *Data, size_t Size,
+                                               size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  assert(Size);
+  size_t ShuffleAmount =
+      Rand(std::min(Size, (size_t)8)) + 1; // [1,8] and <= Size.
+  size_t ShuffleStart = Rand(Size - ShuffleAmount);
+  assert(ShuffleStart + ShuffleAmount <= Size);
+  std::random_shuffle(Data + ShuffleStart, Data + ShuffleStart + ShuffleAmount,
+                      Rand);
+  return Size;
+}
+
+size_t MutationDispatcher::Mutate_EraseBytes(uint8_t *Data, size_t Size,
+                                             size_t MaxSize) {
+  assert(Size);
+  if (Size == 1) return 0;
+  size_t N = Rand(Size / 2) + 1;
+  assert(N < Size);
+  size_t Idx = Rand(Size - N + 1);
+  // Erase Data[Idx:Idx+N].
+  memmove(Data + Idx, Data + Idx + N, Size - Idx - N);
+  // Printf("Erase: %zd %zd => %zd; Idx %zd\n", N, Size, Size - N, Idx);
+  return Size - N;
+}
+
+size_t MutationDispatcher::Mutate_InsertByte(uint8_t *Data, size_t Size,
+                                             size_t MaxSize) {
+  if (Size >= MaxSize) return 0;
+  size_t Idx = Rand(Size + 1);
+  // Insert new value at Data[Idx].
+  memmove(Data + Idx + 1, Data + Idx, Size - Idx);
+  Data[Idx] = RandCh(Rand);
+  return Size + 1;
+}
+
+size_t MutationDispatcher::Mutate_InsertRepeatedBytes(uint8_t *Data,
+                                                      size_t Size,
+                                                      size_t MaxSize) {
+  const size_t kMinBytesToInsert = 3;
+  if (Size + kMinBytesToInsert >= MaxSize) return 0;
+  size_t MaxBytesToInsert = std::min(MaxSize - Size, (size_t)128);
+  size_t N = Rand(MaxBytesToInsert - kMinBytesToInsert + 1) + kMinBytesToInsert;
+  assert(Size + N <= MaxSize && N);
+  size_t Idx = Rand(Size + 1);
+  // Insert new values at Data[Idx].
+  memmove(Data + Idx + N, Data + Idx, Size - Idx);
+  // Give preference to 0x00 and 0xff.
+  uint8_t Byte = Rand.RandBool() ? Rand(256) : (Rand.RandBool() ? 0 : 255);
+  for (size_t i = 0; i < N; i++)
+    Data[Idx + i] = Byte;
+  return Size + N;
+}
+
+size_t MutationDispatcher::Mutate_ChangeByte(uint8_t *Data, size_t Size,
+                                             size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  size_t Idx = Rand(Size);
+  Data[Idx] = RandCh(Rand);
+  return Size;
+}
+
+size_t MutationDispatcher::Mutate_ChangeBit(uint8_t *Data, size_t Size,
+                                            size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  size_t Idx = Rand(Size);
+  Data[Idx] ^= 1 << Rand(8);
+  return Size;
+}
+
+size_t MutationDispatcher::Mutate_AddWordFromManualDictionary(uint8_t *Data,
+                                                              size_t Size,
+                                                              size_t MaxSize) {
+  return AddWordFromDictionary(ManualDictionary, Data, Size, MaxSize);
+}
+
+size_t MutationDispatcher::Mutate_AddWordFromTemporaryAutoDictionary(
+    uint8_t *Data, size_t Size, size_t MaxSize) {
+  return AddWordFromDictionary(TempAutoDictionary, Data, Size, MaxSize);
+}
+
+size_t MutationDispatcher::ApplyDictionaryEntry(uint8_t *Data, size_t Size,
+                                                size_t MaxSize,
+                                                DictionaryEntry &DE) {
+  const Word &W = DE.GetW();
+  bool UsePositionHint = DE.HasPositionHint() &&
+                         DE.GetPositionHint() + W.size() < Size &&
+                         Rand.RandBool();
+  if (Rand.RandBool()) {  // Insert W.
+    if (Size + W.size() > MaxSize) return 0;
+    size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size + 1);
+    memmove(Data + Idx + W.size(), Data + Idx, Size - Idx);
+    memcpy(Data + Idx, W.data(), W.size());
+    Size += W.size();
+  } else {  // Overwrite some bytes with W.
+    if (W.size() > Size) return 0;
+    size_t Idx = UsePositionHint ? DE.GetPositionHint() : Rand(Size - W.size());
+    memcpy(Data + Idx, W.data(), W.size());
+  }
+  return Size;
+}
+
+// Somewhere in the past we have observed a comparison instructions
+// with arguments Arg1 Arg2. This function tries to guess a dictionary
+// entry that will satisfy that comparison.
+// It first tries to find one of the arguments (possibly swapped) in the
+// input and if it succeeds it creates a DE with a position hint.
+// Otherwise it creates a DE with one of the arguments w/o a position hint.
+template <class T>
+DictionaryEntry MutationDispatcher::MakeDictionaryEntryFromCMP(
+    T Arg1, T Arg2, const uint8_t *Data, size_t Size) {
+  ScopedDoingMyOwnMemmem scoped_doing_my_own_memmem;
+  bool HandleFirst = Rand.RandBool();
+  T ExistingBytes, DesiredBytes;
+  Word W;
+  const uint8_t *End = Data + Size;
+  for (int Arg = 0; Arg < 2; Arg++) {
+    ExistingBytes = HandleFirst ? Arg1 : Arg2;
+    DesiredBytes = HandleFirst ? Arg2 : Arg1;
+    DesiredBytes += Rand(-1, 1);
+    if (Rand.RandBool()) ExistingBytes = Bswap(ExistingBytes);
+    if (Rand.RandBool()) DesiredBytes = Bswap(DesiredBytes);
+    HandleFirst = !HandleFirst;
+    W.Set(reinterpret_cast<uint8_t*>(&DesiredBytes), sizeof(T));
+    const size_t kMaxNumPositions = 8;
+    size_t Positions[kMaxNumPositions];
+    size_t NumPositions = 0;
+    for (const uint8_t *Cur = Data;
+         Cur < End && NumPositions < kMaxNumPositions; Cur++) {
+      Cur = (uint8_t *)SearchMemory(Cur, End - Cur, &ExistingBytes, sizeof(T));
+      if (!Cur) break;
+      Positions[NumPositions++] = Cur - Data;
+    }
+    if (!NumPositions) break;
+    return DictionaryEntry(W, Positions[Rand(NumPositions)]);
+  }
+  DictionaryEntry DE(W);
+  return DE;
+}
+
+size_t MutationDispatcher::Mutate_AddWordFromTORC(
+    uint8_t *Data, size_t Size, size_t MaxSize) {
+  Word W;
+  DictionaryEntry DE;
+  if (Rand.RandBool()) {
+    auto X = TPC.TORC8.Get(Rand.Rand());
+    DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
+  } else {
+    auto X = TPC.TORC4.Get(Rand.Rand());
+    if ((X.A >> 16) == 0 && (X.B >> 16) == 0 && Rand.RandBool())
+      DE = MakeDictionaryEntryFromCMP((uint16_t)X.A, (uint16_t)X.B, Data,
+                                      Size);
+    else
+      DE = MakeDictionaryEntryFromCMP(X.A, X.B, Data, Size);
+  }
+  Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
+  if (!Size) return 0;
+  DictionaryEntry &DERef =
+      CmpDictionaryEntriesDeque[CmpDictionaryEntriesDequeIdx++ %
+                                kCmpDictionaryEntriesDequeSize];
+  DERef = DE;
+  CurrentDictionaryEntrySequence.push_back(&DERef);
+  return Size;
+}
+
+size_t MutationDispatcher::Mutate_AddWordFromPersistentAutoDictionary(
+    uint8_t *Data, size_t Size, size_t MaxSize) {
+  return AddWordFromDictionary(PersistentAutoDictionary, Data, Size, MaxSize);
+}
+
+size_t MutationDispatcher::AddWordFromDictionary(Dictionary &D, uint8_t *Data,
+                                                 size_t Size, size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  if (D.empty()) return 0;
+  DictionaryEntry &DE = D[Rand(D.size())];
+  Size = ApplyDictionaryEntry(Data, Size, MaxSize, DE);
+  if (!Size) return 0;
+  DE.IncUseCount();
+  CurrentDictionaryEntrySequence.push_back(&DE);
+  return Size;
+}
+
+// Overwrites part of To[0,ToSize) with a part of From[0,FromSize).
+// Returns ToSize.
+size_t MutationDispatcher::CopyPartOf(const uint8_t *From, size_t FromSize,
+                                      uint8_t *To, size_t ToSize) {
+  // Copy From[FromBeg, FromBeg + CopySize) into To[ToBeg, ToBeg + CopySize).
+  size_t ToBeg = Rand(ToSize);
+  size_t CopySize = Rand(ToSize - ToBeg) + 1;
+  assert(ToBeg + CopySize <= ToSize);
+  CopySize = std::min(CopySize, FromSize);
+  size_t FromBeg = Rand(FromSize - CopySize + 1);
+  assert(FromBeg + CopySize <= FromSize);
+  memmove(To + ToBeg, From + FromBeg, CopySize);
+  return ToSize;
+}
+
+// Inserts part of From[0,ToSize) into To.
+// Returns new size of To on success or 0 on failure.
+size_t MutationDispatcher::InsertPartOf(const uint8_t *From, size_t FromSize,
+                                        uint8_t *To, size_t ToSize,
+                                        size_t MaxToSize) {
+  if (ToSize >= MaxToSize) return 0;
+  size_t AvailableSpace = MaxToSize - ToSize;
+  size_t MaxCopySize = std::min(AvailableSpace, FromSize);
+  size_t CopySize = Rand(MaxCopySize) + 1;
+  size_t FromBeg = Rand(FromSize - CopySize + 1);
+  assert(FromBeg + CopySize <= FromSize);
+  size_t ToInsertPos = Rand(ToSize + 1);
+  assert(ToInsertPos + CopySize <= MaxToSize);
+  size_t TailSize = ToSize - ToInsertPos;
+  if (To == From) {
+    MutateInPlaceHere.resize(MaxToSize);
+    memcpy(MutateInPlaceHere.data(), From + FromBeg, CopySize);
+    memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
+    memmove(To + ToInsertPos, MutateInPlaceHere.data(), CopySize);
+  } else {
+    memmove(To + ToInsertPos + CopySize, To + ToInsertPos, TailSize);
+    memmove(To + ToInsertPos, From + FromBeg, CopySize);
+  }
+  return ToSize + CopySize;
+}
+
+size_t MutationDispatcher::Mutate_CopyPart(uint8_t *Data, size_t Size,
+                                           size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  if (Rand.RandBool())
+    return CopyPartOf(Data, Size, Data, Size);
+  else
+    return InsertPartOf(Data, Size, Data, Size, MaxSize);
+}
+
+size_t MutationDispatcher::Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size,
+                                                     size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  size_t B = Rand(Size);
+  while (B < Size && !isdigit(Data[B])) B++;
+  if (B == Size) return 0;
+  size_t E = B;
+  while (E < Size && isdigit(Data[E])) E++;
+  assert(B < E);
+  // now we have digits in [B, E).
+  // strtol and friends don't accept non-zero-teminated data, parse it manually.
+  uint64_t Val = Data[B] - '0';
+  for (size_t i = B + 1; i < E; i++)
+    Val = Val * 10 + Data[i] - '0';
+
+  // Mutate the integer value.
+  switch(Rand(5)) {
+    case 0: Val++; break;
+    case 1: Val--; break;
+    case 2: Val /= 2; break;
+    case 3: Val *= 2; break;
+    case 4: Val = Rand(Val * Val); break;
+    default: assert(0);
+  }
+  // Just replace the bytes with the new ones, don't bother moving bytes.
+  for (size_t i = B; i < E; i++) {
+    size_t Idx = E + B - i - 1;
+    assert(Idx >= B && Idx < E);
+    Data[Idx] = (Val % 10) + '0';
+    Val /= 10;
+  }
+  return Size;
+}
+
+template<class T>
+size_t ChangeBinaryInteger(uint8_t *Data, size_t Size, Random &Rand) {
+  if (Size < sizeof(T)) return 0;
+  size_t Off = Rand(Size - sizeof(T) + 1);
+  assert(Off + sizeof(T) <= Size);
+  T Val;
+  if (Off < 64 && !Rand(4)) {
+    Val = Size;
+    if (Rand.RandBool())
+      Val = Bswap(Val);
+  } else {
+    memcpy(&Val, Data + Off, sizeof(Val));
+    T Add = Rand(21);
+    Add -= 10;
+    if (Rand.RandBool())
+      Val = Bswap(T(Bswap(Val) + Add)); // Add assuming different endiannes.
+    else
+      Val = Val + Add;               // Add assuming current endiannes.
+    if (Add == 0 || Rand.RandBool()) // Maybe negate.
+      Val = -Val;
+  }
+  memcpy(Data + Off, &Val, sizeof(Val));
+  return Size;
+}
+
+size_t MutationDispatcher::Mutate_ChangeBinaryInteger(uint8_t *Data,
+                                                      size_t Size,
+                                                      size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  switch (Rand(4)) {
+    case 3: return ChangeBinaryInteger<uint64_t>(Data, Size, Rand);
+    case 2: return ChangeBinaryInteger<uint32_t>(Data, Size, Rand);
+    case 1: return ChangeBinaryInteger<uint16_t>(Data, Size, Rand);
+    case 0: return ChangeBinaryInteger<uint8_t>(Data, Size, Rand);
+    default: assert(0);
+  }
+  return 0;
+}
+
+size_t MutationDispatcher::Mutate_CrossOver(uint8_t *Data, size_t Size,
+                                            size_t MaxSize) {
+  if (Size > MaxSize) return 0;
+  if (!Corpus || Corpus->size() < 2 || Size == 0) return 0;
+  size_t Idx = Rand(Corpus->size());
+  const Unit &O = (*Corpus)[Idx];
+  if (O.empty()) return 0;
+  MutateInPlaceHere.resize(MaxSize);
+  auto &U = MutateInPlaceHere;
+  size_t NewSize = 0;
+  switch(Rand(3)) {
+    case 0:
+      NewSize = CrossOver(Data, Size, O.data(), O.size(), U.data(), U.size());
+      break;
+    case 1:
+      NewSize = InsertPartOf(O.data(), O.size(), U.data(), U.size(), MaxSize);
+      if (NewSize)
+        break;
+      // LLVM_FALLTHROUGH;
+    case 2:
+      NewSize = CopyPartOf(O.data(), O.size(), U.data(), U.size());
+      break;
+    default: assert(0);
+  }
+  assert(NewSize > 0 && "CrossOver returned empty unit");
+  assert(NewSize <= MaxSize && "CrossOver returned overisized unit");
+  memcpy(Data, U.data(), NewSize);
+  return NewSize;
+}
+
+void MutationDispatcher::StartMutationSequence() {
+  CurrentMutatorSequence.clear();
+  CurrentDictionaryEntrySequence.clear();
+}
+
+// Copy successful dictionary entries to PersistentAutoDictionary.
+void MutationDispatcher::RecordSuccessfulMutationSequence() {
+  for (auto DE : CurrentDictionaryEntrySequence) {
+    // PersistentAutoDictionary.AddWithSuccessCountOne(DE);
+    DE->IncSuccessCount();
+    // Linear search is fine here as this happens seldom.
+    if (!PersistentAutoDictionary.ContainsWord(DE->GetW()))
+      PersistentAutoDictionary.push_back({DE->GetW(), 1});
+  }
+}
+
+void MutationDispatcher::PrintRecommendedDictionary() {
+  std::vector<DictionaryEntry> V;
+  for (auto &DE : PersistentAutoDictionary)
+    if (!ManualDictionary.ContainsWord(DE.GetW()))
+      V.push_back(DE);
+  if (V.empty()) return;
+  Printf("###### Recommended dictionary. ######\n");
+  for (auto &DE: V) {
+    Printf("\"");
+    PrintASCII(DE.GetW(), "\"");
+    Printf(" # Uses: %zd\n", DE.GetUseCount());
+  }
+  Printf("###### End of recommended dictionary. ######\n");
+}
+
+void MutationDispatcher::PrintMutationSequence() {
+  Printf("MS: %zd ", CurrentMutatorSequence.size());
+  for (auto M : CurrentMutatorSequence)
+    Printf("%s-", M.Name);
+  if (!CurrentDictionaryEntrySequence.empty()) {
+    Printf(" DE: ");
+    for (auto DE : CurrentDictionaryEntrySequence) {
+      Printf("\"");
+      PrintASCII(DE->GetW(), "\"-");
+    }
+  }
+}
+
+size_t MutationDispatcher::Mutate(uint8_t *Data, size_t Size, size_t MaxSize) {
+  return MutateImpl(Data, Size, MaxSize, Mutators);
+}
+
+size_t MutationDispatcher::DefaultMutate(uint8_t *Data, size_t Size,
+                                         size_t MaxSize) {
+  return MutateImpl(Data, Size, MaxSize, DefaultMutators);
+}
+
+// Mutates Data in place, returns new size.
+size_t MutationDispatcher::MutateImpl(uint8_t *Data, size_t Size,
+                                      size_t MaxSize,
+                                      const std::vector<Mutator> &Mutators) {
+  assert(MaxSize > 0);
+  if (Size == 0) {
+    for (size_t i = 0; i < MaxSize; i++)
+      Data[i] = RandCh(Rand);
+    if (Options.OnlyASCII)
+      ToASCII(Data, MaxSize);
+    return MaxSize;
+  }
+  assert(Size > 0);
+  // Some mutations may fail (e.g. can't insert more bytes if Size == MaxSize),
+  // in which case they will return 0.
+  // Try several times before returning un-mutated data.
+  for (int Iter = 0; Iter < 100; Iter++) {
+    auto M = Mutators[Rand(Mutators.size())];
+    size_t NewSize = (this->*(M.Fn))(Data, Size, MaxSize);
+    if (NewSize && NewSize <= MaxSize) {
+      if (Options.OnlyASCII)
+        ToASCII(Data, NewSize);
+      CurrentMutatorSequence.push_back(M);
+      return NewSize;
+    }
+  }
+  return std::min(Size, MaxSize);
+}
+
+void MutationDispatcher::AddWordToManualDictionary(const Word &W) {
+  ManualDictionary.push_back(
+      {W, std::numeric_limits<size_t>::max()});
+}
+
+void MutationDispatcher::AddWordToAutoDictionary(DictionaryEntry DE) {
+  static const size_t kMaxAutoDictSize = 1 << 14;
+  if (TempAutoDictionary.size() >= kMaxAutoDictSize) return;
+  TempAutoDictionary.push_back(DE);
+}
+
+void MutationDispatcher::ClearAutoDictionary() {
+  TempAutoDictionary.clear();
+}
+
+}  // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerMutate.h

@@ -0,0 +1,145 @@
+//===- FuzzerMutate.h - Internal header for the Fuzzer ----------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::MutationDispatcher
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_MUTATE_H
+#define LLVM_FUZZER_MUTATE_H
+
+#include "FuzzerDefs.h"
+#include "FuzzerDictionary.h"
+#include "FuzzerRandom.h"
+
+namespace fuzzer {
+
+class MutationDispatcher {
+public:
+  MutationDispatcher(Random &Rand, const FuzzingOptions &Options);
+  ~MutationDispatcher() {}
+  /// Indicate that we are about to start a new sequence of mutations.
+  void StartMutationSequence();
+  /// Print the current sequence of mutations.
+  void PrintMutationSequence();
+  /// Indicate that the current sequence of mutations was successfull.
+  void RecordSuccessfulMutationSequence();
+  /// Mutates data by invoking user-provided mutator.
+  size_t Mutate_Custom(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by invoking user-provided crossover.
+  size_t Mutate_CustomCrossOver(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by shuffling bytes.
+  size_t Mutate_ShuffleBytes(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by erasing bytes.
+  size_t Mutate_EraseBytes(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by inserting a byte.
+  size_t Mutate_InsertByte(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by inserting several repeated bytes.
+  size_t Mutate_InsertRepeatedBytes(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by chanding one byte.
+  size_t Mutate_ChangeByte(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by chanding one bit.
+  size_t Mutate_ChangeBit(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Mutates data by copying/inserting a part of data into a different place.
+  size_t Mutate_CopyPart(uint8_t *Data, size_t Size, size_t MaxSize);
+
+  /// Mutates data by adding a word from the manual dictionary.
+  size_t Mutate_AddWordFromManualDictionary(uint8_t *Data, size_t Size,
+                                            size_t MaxSize);
+
+  /// Mutates data by adding a word from the temporary automatic dictionary.
+  size_t Mutate_AddWordFromTemporaryAutoDictionary(uint8_t *Data, size_t Size,
+                                                   size_t MaxSize);
+
+  /// Mutates data by adding a word from the TORC.
+  size_t Mutate_AddWordFromTORC(uint8_t *Data, size_t Size, size_t MaxSize);
+
+  /// Mutates data by adding a word from the persistent automatic dictionary.
+  size_t Mutate_AddWordFromPersistentAutoDictionary(uint8_t *Data, size_t Size,
+                                                    size_t MaxSize);
+
+  /// Tries to find an ASCII integer in Data, changes it to another ASCII int.
+  size_t Mutate_ChangeASCIIInteger(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Change a 1-, 2-, 4-, or 8-byte integer in interesting ways.
+  size_t Mutate_ChangeBinaryInteger(uint8_t *Data, size_t Size, size_t MaxSize);
+
+  /// CrossOver Data with some other element of the corpus.
+  size_t Mutate_CrossOver(uint8_t *Data, size_t Size, size_t MaxSize);
+
+  /// Applies one of the configured mutations.
+  /// Returns the new size of data which could be up to MaxSize.
+  size_t Mutate(uint8_t *Data, size_t Size, size_t MaxSize);
+  /// Applies one of the default mutations. Provided as a service
+  /// to mutation authors.
+  size_t DefaultMutate(uint8_t *Data, size_t Size, size_t MaxSize);
+
+  /// Creates a cross-over of two pieces of Data, returns its size.
+  size_t CrossOver(const uint8_t *Data1, size_t Size1, const uint8_t *Data2,
+                   size_t Size2, uint8_t *Out, size_t MaxOutSize);
+
+  void AddWordToManualDictionary(const Word &W);
+
+  void AddWordToAutoDictionary(DictionaryEntry DE);
+  void ClearAutoDictionary();
+  void PrintRecommendedDictionary();
+
+  void SetCorpus(const InputCorpus *Corpus) { this->Corpus = Corpus; }
+
+  Random &GetRand() { return Rand; }
+
+private:
+
+  struct Mutator {
+    size_t (MutationDispatcher::*Fn)(uint8_t *Data, size_t Size, size_t Max);
+    const char *Name;
+  };
+
+  size_t AddWordFromDictionary(Dictionary &D, uint8_t *Data, size_t Size,
+                               size_t MaxSize);
+  size_t MutateImpl(uint8_t *Data, size_t Size, size_t MaxSize,
+                    const std::vector<Mutator> &Mutators);
+
+  size_t InsertPartOf(const uint8_t *From, size_t FromSize, uint8_t *To,
+                      size_t ToSize, size_t MaxToSize);
+  size_t CopyPartOf(const uint8_t *From, size_t FromSize, uint8_t *To,
+                    size_t ToSize);
+  size_t ApplyDictionaryEntry(uint8_t *Data, size_t Size, size_t MaxSize,
+                              DictionaryEntry &DE);
+
+  template <class T>
+  DictionaryEntry MakeDictionaryEntryFromCMP(T Arg1, T Arg2,
+                                             const uint8_t *Data, size_t Size);
+
+  Random &Rand;
+  const FuzzingOptions &Options;
+
+  // Dictionary provided by the user via -dict=DICT_FILE.
+  Dictionary ManualDictionary;
+  // Temporary dictionary modified by the fuzzer itself,
+  // recreated periodically.
+  Dictionary TempAutoDictionary;
+  // Persistent dictionary modified by the fuzzer, consists of
+  // entries that led to successfull discoveries in the past mutations.
+  Dictionary PersistentAutoDictionary;
+
+  std::vector<Mutator> CurrentMutatorSequence;
+  std::vector<DictionaryEntry *> CurrentDictionaryEntrySequence;
+
+  static const size_t kCmpDictionaryEntriesDequeSize = 16;
+  DictionaryEntry CmpDictionaryEntriesDeque[kCmpDictionaryEntriesDequeSize];
+  size_t CmpDictionaryEntriesDequeIdx = 0;
+
+  const InputCorpus *Corpus = nullptr;
+  std::vector<uint8_t> MutateInPlaceHere;
+
+  std::vector<Mutator> Mutators;
+  std::vector<Mutator> DefaultMutators;
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_MUTATE_H

test/fuzz_test/Fuzzer/FuzzerOptions.h

@@ -0,0 +1,68 @@
+//===- FuzzerOptions.h - Internal header for the Fuzzer ---------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::FuzzingOptions
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_OPTIONS_H
+#define LLVM_FUZZER_OPTIONS_H
+
+#include "FuzzerDefs.h"
+
+namespace fuzzer {
+
+struct FuzzingOptions {
+  int Verbosity = 1;
+  size_t MaxLen = 0;
+  int UnitTimeoutSec = 300;
+  int TimeoutExitCode = 77;
+  int ErrorExitCode = 77;
+  int MaxTotalTimeSec = 0;
+  int RssLimitMb = 0;
+  bool DoCrossOver = true;
+  int MutateDepth = 5;
+  bool UseCounters = false;
+  bool UseIndirCalls = true;
+  bool UseMemcmp = true;
+  bool UseMemmem = true;
+  bool UseCmp = false;
+  bool UseValueProfile = false;
+  bool Shrink = false;
+  int ReloadIntervalSec = 1;
+  bool ShuffleAtStartUp = true;
+  bool PreferSmall = true;
+  size_t MaxNumberOfRuns = -1L;
+  int ReportSlowUnits = 10;
+  bool OnlyASCII = false;
+  std::string OutputCorpus;
+  std::string ArtifactPrefix = "./";
+  std::string ExactArtifactPath;
+  std::string ExitOnSrcPos;
+  std::string ExitOnItem;
+  bool SaveArtifacts = true;
+  bool PrintNEW = true; // Print a status line when new units are found;
+  bool OutputCSV = false;
+  bool PrintNewCovPcs = false;
+  bool PrintFinalStats = false;
+  bool PrintCorpusStats = false;
+  bool PrintCoverage = false;
+  bool DumpCoverage = false;
+  bool DetectLeaks = true;
+  int  TraceMalloc = 0;
+  bool HandleAbrt = false;
+  bool HandleBus = false;
+  bool HandleFpe = false;
+  bool HandleIll = false;
+  bool HandleInt = false;
+  bool HandleSegv = false;
+  bool HandleTerm = false;
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_OPTIONS_H

test/fuzz_test/Fuzzer/FuzzerRandom.h

@@ -0,0 +1,36 @@
+//===- FuzzerRandom.h - Internal header for the Fuzzer ----------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::Random
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_RANDOM_H
+#define LLVM_FUZZER_RANDOM_H
+
+#include <random>
+
+namespace fuzzer {
+class Random {
+ public:
+  Random(unsigned int seed) : R(seed) {}
+  size_t Rand() { return R(); }
+  size_t RandBool() { return Rand() % 2; }
+  size_t operator()(size_t n) { return n ? Rand() % n : 0; }
+  intptr_t operator()(intptr_t From, intptr_t To) {
+    assert(From < To);
+    intptr_t RangeSize = To - From + 1;
+    return operator()(RangeSize) + From;
+  }
+  std::mt19937 &Get_mt19937() { return R; }
+ private:
+  std::mt19937 R;
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_RANDOM_H

test/fuzz_test/Fuzzer/FuzzerSHA1.cpp

@@ -0,0 +1,222 @@
+//===- FuzzerSHA1.h - Private copy of the SHA1 implementation ---*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// This code is taken from public domain
+// (http://oauth.googlecode.com/svn/code/c/liboauth/src/sha1.c)
+// and modified by adding anonymous namespace, adding an interface
+// function fuzzer::ComputeSHA1() and removing unnecessary code.
+//
+// lib/Fuzzer can not use SHA1 implementation from openssl because
+// openssl may not be available and because we may be fuzzing openssl itself.
+// For the same reason we do not want to depend on SHA1 from LLVM tree.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerSHA1.h"
+#include "FuzzerDefs.h"
+
+/* This code is public-domain - it is based on libcrypt
+ * placed in the public domain by Wei Dai and other contributors.
+ */
+
+#include <iomanip>
+#include <sstream>
+#include <stdint.h>
+#include <string.h>
+
+namespace {  // Added for LibFuzzer
+
+#ifdef __BIG_ENDIAN__
+# define SHA_BIG_ENDIAN
+#elif defined __LITTLE_ENDIAN__
+/* override */
+#elif defined __BYTE_ORDER
+# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__
+# define SHA_BIG_ENDIAN
+# endif
+#else // ! defined __LITTLE_ENDIAN__
+# include <endian.h> // machine/endian.h
+# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__
+#  define SHA_BIG_ENDIAN
+# endif
+#endif
+
+
+/* header */
+
+#define HASH_LENGTH 20
+#define BLOCK_LENGTH 64
+
+typedef struct sha1nfo {
+	uint32_t buffer[BLOCK_LENGTH/4];
+	uint32_t state[HASH_LENGTH/4];
+	uint32_t byteCount;
+	uint8_t bufferOffset;
+	uint8_t keyBuffer[BLOCK_LENGTH];
+	uint8_t innerHash[HASH_LENGTH];
+} sha1nfo;
+
+/* public API - prototypes - TODO: doxygen*/
+
+/**
+ */
+void sha1_init(sha1nfo *s);
+/**
+ */
+void sha1_writebyte(sha1nfo *s, uint8_t data);
+/**
+ */
+void sha1_write(sha1nfo *s, const char *data, size_t len);
+/**
+ */
+uint8_t* sha1_result(sha1nfo *s);
+
+
+/* code */
+#define SHA1_K0  0x5a827999
+#define SHA1_K20 0x6ed9eba1
+#define SHA1_K40 0x8f1bbcdc
+#define SHA1_K60 0xca62c1d6
+
+void sha1_init(sha1nfo *s) {
+	s->state[0] = 0x67452301;
+	s->state[1] = 0xefcdab89;
+	s->state[2] = 0x98badcfe;
+	s->state[3] = 0x10325476;
+	s->state[4] = 0xc3d2e1f0;
+	s->byteCount = 0;
+	s->bufferOffset = 0;
+}
+
+uint32_t sha1_rol32(uint32_t number, uint8_t bits) {
+	return ((number << bits) | (number >> (32-bits)));
+}
+
+void sha1_hashBlock(sha1nfo *s) {
+	uint8_t i;
+	uint32_t a,b,c,d,e,t;
+
+	a=s->state[0];
+	b=s->state[1];
+	c=s->state[2];
+	d=s->state[3];
+	e=s->state[4];
+	for (i=0; i<80; i++) {
+		if (i>=16) {
+			t = s->buffer[(i+13)&15] ^ s->buffer[(i+8)&15] ^ s->buffer[(i+2)&15] ^ s->buffer[i&15];
+			s->buffer[i&15] = sha1_rol32(t,1);
+		}
+		if (i<20) {
+			t = (d ^ (b & (c ^ d))) + SHA1_K0;
+		} else if (i<40) {
+			t = (b ^ c ^ d) + SHA1_K20;
+		} else if (i<60) {
+			t = ((b & c) | (d & (b | c))) + SHA1_K40;
+		} else {
+			t = (b ^ c ^ d) + SHA1_K60;
+		}
+		t+=sha1_rol32(a,5) + e + s->buffer[i&15];
+		e=d;
+		d=c;
+		c=sha1_rol32(b,30);
+		b=a;
+		a=t;
+	}
+	s->state[0] += a;
+	s->state[1] += b;
+	s->state[2] += c;
+	s->state[3] += d;
+	s->state[4] += e;
+}
+
+void sha1_addUncounted(sha1nfo *s, uint8_t data) {
+	uint8_t * const b = (uint8_t*) s->buffer;
+#ifdef SHA_BIG_ENDIAN
+	b[s->bufferOffset] = data;
+#else
+	b[s->bufferOffset ^ 3] = data;
+#endif
+	s->bufferOffset++;
+	if (s->bufferOffset == BLOCK_LENGTH) {
+		sha1_hashBlock(s);
+		s->bufferOffset = 0;
+	}
+}
+
+void sha1_writebyte(sha1nfo *s, uint8_t data) {
+	++s->byteCount;
+	sha1_addUncounted(s, data);
+}
+
+void sha1_write(sha1nfo *s, const char *data, size_t len) {
+	for (;len--;) sha1_writebyte(s, (uint8_t) *data++);
+}
+
+void sha1_pad(sha1nfo *s) {
+	// Implement SHA-1 padding (fips180-2 §5.1.1)
+
+	// Pad with 0x80 followed by 0x00 until the end of the block
+	sha1_addUncounted(s, 0x80);
+	while (s->bufferOffset != 56) sha1_addUncounted(s, 0x00);
+
+	// Append length in the last 8 bytes
+	sha1_addUncounted(s, 0); // We're only using 32 bit lengths
+	sha1_addUncounted(s, 0); // But SHA-1 supports 64 bit lengths
+	sha1_addUncounted(s, 0); // So zero pad the top bits
+	sha1_addUncounted(s, s->byteCount >> 29); // Shifting to multiply by 8
+	sha1_addUncounted(s, s->byteCount >> 21); // as SHA-1 supports bitstreams as well as
+	sha1_addUncounted(s, s->byteCount >> 13); // byte.
+	sha1_addUncounted(s, s->byteCount >> 5);
+	sha1_addUncounted(s, s->byteCount << 3);
+}
+
+uint8_t* sha1_result(sha1nfo *s) {
+	// Pad to complete the last block
+	sha1_pad(s);
+
+#ifndef SHA_BIG_ENDIAN
+	// Swap byte order back
+	int i;
+	for (i=0; i<5; i++) {
+		s->state[i]=
+			  (((s->state[i])<<24)& 0xff000000)
+			| (((s->state[i])<<8) & 0x00ff0000)
+			| (((s->state[i])>>8) & 0x0000ff00)
+			| (((s->state[i])>>24)& 0x000000ff);
+	}
+#endif
+
+	// Return pointer to hash (20 characters)
+	return (uint8_t*) s->state;
+}
+
+}  // namespace; Added for LibFuzzer
+
+namespace fuzzer {
+
+// The rest is added for LibFuzzer
+void ComputeSHA1(const uint8_t *Data, size_t Len, uint8_t *Out) {
+  sha1nfo s;
+  sha1_init(&s);
+  sha1_write(&s, (const char*)Data, Len);
+  memcpy(Out, sha1_result(&s), HASH_LENGTH);
+}
+
+std::string Sha1ToString(const uint8_t Sha1[kSHA1NumBytes]) {
+  std::stringstream SS;
+  for (int i = 0; i < kSHA1NumBytes; i++)
+    SS << std::hex << std::setfill('0') << std::setw(2) << (unsigned)Sha1[i];
+  return SS.str();
+}
+
+std::string Hash(const Unit &U) {
+  uint8_t Hash[kSHA1NumBytes];
+  ComputeSHA1(U.data(), U.size(), Hash);
+  return Sha1ToString(Hash);
+}
+
+}

test/fuzz_test/Fuzzer/FuzzerSHA1.h

@@ -0,0 +1,33 @@
+//===- FuzzerSHA1.h - Internal header for the SHA1 utils --------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// SHA1 utils.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_SHA1_H
+#define LLVM_FUZZER_SHA1_H
+
+#include "FuzzerDefs.h"
+#include <cstddef>
+#include <stdint.h>
+
+namespace fuzzer {
+
+// Private copy of SHA1 implementation.
+static const int kSHA1NumBytes = 20;
+
+// Computes SHA1 hash of 'Len' bytes in 'Data', writes kSHA1NumBytes to 'Out'.
+void ComputeSHA1(const uint8_t *Data, size_t Len, uint8_t *Out);
+
+std::string Sha1ToString(const uint8_t Sha1[kSHA1NumBytes]);
+
+std::string Hash(const Unit &U);
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_SHA1_H

test/fuzz_test/Fuzzer/FuzzerTracePC.cpp

@@ -0,0 +1,339 @@
+//===- FuzzerTracePC.cpp - PC tracing--------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Trace PCs.
+// This module implements __sanitizer_cov_trace_pc_guard[_init],
+// the callback required for -fsanitize-coverage=trace-pc-guard instrumentation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerCorpus.h"
+#include "FuzzerDefs.h"
+#include "FuzzerDictionary.h"
+#include "FuzzerExtFunctions.h"
+#include "FuzzerIO.h"
+#include "FuzzerTracePC.h"
+#include "FuzzerValueBitMap.h"
+#include <map>
+#include <sanitizer/coverage_interface.h>
+#include <set>
+#include <sstream>
+
+namespace fuzzer {
+
+TracePC TPC;
+
+void TracePC::HandleTrace(uint32_t *Guard, uintptr_t PC) {
+  uint32_t Idx = *Guard;
+  if (!Idx) return;
+  PCs[Idx % kNumPCs] = PC;
+  Counters[Idx % kNumCounters]++;
+}
+
+size_t TracePC::GetTotalPCCoverage() {
+  size_t Res = 0;
+  for (size_t i = 1; i < GetNumPCs(); i++)
+    if (PCs[i])
+      Res++;
+  return Res;
+}
+
+void TracePC::HandleInit(uint32_t *Start, uint32_t *Stop) {
+  if (Start == Stop || *Start) return;
+  assert(NumModules < sizeof(Modules) / sizeof(Modules[0]));
+  for (uint32_t *P = Start; P < Stop; P++)
+    *P = ++NumGuards;
+  Modules[NumModules].Start = Start;
+  Modules[NumModules].Stop = Stop;
+  NumModules++;
+}
+
+void TracePC::PrintModuleInfo() {
+  Printf("INFO: Loaded %zd modules (%zd guards): ", NumModules, NumGuards);
+  for (size_t i = 0; i < NumModules; i++)
+    Printf("[%p, %p), ", Modules[i].Start, Modules[i].Stop);
+  Printf("\n");
+}
+
+void TracePC::HandleCallerCallee(uintptr_t Caller, uintptr_t Callee) {
+  const uintptr_t kBits = 12;
+  const uintptr_t kMask = (1 << kBits) - 1;
+  uintptr_t Idx = (Caller & kMask) | ((Callee & kMask) << kBits);
+  HandleValueProfile(Idx);
+}
+
+static bool IsInterestingCoverageFile(std::string &File) {
+  if (File.find("compiler-rt/lib/") != std::string::npos)
+    return false; // sanitizer internal.
+  if (File.find("/usr/lib/") != std::string::npos)
+    return false;
+  if (File.find("/usr/include/") != std::string::npos)
+    return false;
+  if (File == "<null>")
+    return false;
+  return true;
+}
+
+void TracePC::PrintNewPCs() {
+  if (DoPrintNewPCs) {
+    if (!PrintedPCs)
+      PrintedPCs = new std::set<uintptr_t>;
+    for (size_t i = 1; i < GetNumPCs(); i++)
+      if (PCs[i] && PrintedPCs->insert(PCs[i]).second)
+        PrintPC("\tNEW_PC: %p %F %L\n", "\tNEW_PC: %p\n", PCs[i]);
+  }
+}
+
+void TracePC::PrintCoverage() {
+  if (!EF->__sanitizer_symbolize_pc ||
+      !EF->__sanitizer_get_module_and_offset_for_pc) {
+    Printf("INFO: __sanitizer_symbolize_pc or "
+           "__sanitizer_get_module_and_offset_for_pc is not available,"
+           " not printing coverage\n");
+    return;
+  }
+  std::map<std::string, std::vector<uintptr_t>> CoveredPCsPerModule;
+  std::map<std::string, uintptr_t> ModuleOffsets;
+  std::set<std::string> CoveredDirs, CoveredFiles, CoveredFunctions,
+      CoveredLines;
+  Printf("COVERAGE:\n");
+  for (size_t i = 1; i < GetNumPCs(); i++) {
+    if (!PCs[i]) continue;
+    std::string FileStr = DescribePC("%s", PCs[i]);
+    if (!IsInterestingCoverageFile(FileStr)) continue;
+    std::string FixedPCStr = DescribePC("%p", PCs[i]);
+    std::string FunctionStr = DescribePC("%F", PCs[i]);
+    std::string LineStr = DescribePC("%l", PCs[i]);
+    char ModulePathRaw[4096] = "";  // What's PATH_MAX in portable C++?
+    void *OffsetRaw = nullptr;
+    if (!EF->__sanitizer_get_module_and_offset_for_pc(
+            reinterpret_cast<void *>(PCs[i]), ModulePathRaw,
+            sizeof(ModulePathRaw), &OffsetRaw))
+      continue;
+    std::string Module = ModulePathRaw;
+    uintptr_t FixedPC = std::stol(FixedPCStr, 0, 16);
+    uintptr_t PcOffset = reinterpret_cast<uintptr_t>(OffsetRaw);
+    ModuleOffsets[Module] = FixedPC - PcOffset;
+    CoveredPCsPerModule[Module].push_back(PcOffset);
+    CoveredFunctions.insert(FunctionStr);
+    CoveredFiles.insert(FileStr);
+    CoveredDirs.insert(DirName(FileStr));
+    if (!CoveredLines.insert(FileStr + ":" + LineStr).second)
+      continue;
+    Printf("COVERED: %s %s:%s\n", FunctionStr.c_str(),
+           FileStr.c_str(), LineStr.c_str());
+  }
+
+  std::string CoveredDirsStr;
+  for (auto &Dir : CoveredDirs) {
+    if (!CoveredDirsStr.empty())
+      CoveredDirsStr += ",";
+    CoveredDirsStr += Dir;
+  }
+  Printf("COVERED_DIRS: %s\n", CoveredDirsStr.c_str());
+
+  for (auto &M : CoveredPCsPerModule) {
+    std::set<std::string> UncoveredFiles, UncoveredFunctions;
+    std::map<std::string, std::set<int> > UncoveredLines;  // Func+File => lines
+    auto &ModuleName = M.first;
+    auto &CoveredOffsets = M.second;
+    uintptr_t ModuleOffset = ModuleOffsets[ModuleName];
+    std::sort(CoveredOffsets.begin(), CoveredOffsets.end());
+    Printf("MODULE_WITH_COVERAGE: %s\n", ModuleName.c_str());
+    // sancov does not yet fully support DSOs.
+    // std::string Cmd = "sancov -print-coverage-pcs " + ModuleName;
+    std::string Cmd = "objdump -d " + ModuleName +
+        " | grep 'call.*__sanitizer_cov_trace_pc_guard' | awk -F: '{print $1}'";
+    std::string SanCovOutput;
+    if (!ExecuteCommandAndReadOutput(Cmd, &SanCovOutput)) {
+      Printf("INFO: Command failed: %s\n", Cmd.c_str());
+      continue;
+    }
+    std::istringstream ISS(SanCovOutput);
+    std::string S;
+    while (std::getline(ISS, S, '\n')) {
+      uintptr_t PcOffset = std::stol(S, 0, 16);
+      if (!std::binary_search(CoveredOffsets.begin(), CoveredOffsets.end(),
+                              PcOffset)) {
+        uintptr_t PC = ModuleOffset + PcOffset;
+        auto FileStr = DescribePC("%s", PC);
+        if (!IsInterestingCoverageFile(FileStr)) continue;
+        if (CoveredFiles.count(FileStr) == 0) {
+          UncoveredFiles.insert(FileStr);
+          continue;
+        }
+        auto FunctionStr = DescribePC("%F", PC);
+        if (CoveredFunctions.count(FunctionStr) == 0) {
+          UncoveredFunctions.insert(FunctionStr);
+          continue;
+        }
+        std::string LineStr = DescribePC("%l", PC);
+        uintptr_t Line = std::stoi(LineStr);
+        std::string FileLineStr = FileStr + ":" + LineStr;
+        if (CoveredLines.count(FileLineStr) == 0)
+          UncoveredLines[FunctionStr + " " + FileStr].insert(Line);
+      }
+    }
+    for (auto &FileLine: UncoveredLines)
+      for (int Line : FileLine.second)
+        Printf("UNCOVERED_LINE: %s:%d\n", FileLine.first.c_str(), Line);
+    for (auto &Func : UncoveredFunctions)
+      Printf("UNCOVERED_FUNC: %s\n", Func.c_str());
+    for (auto &File : UncoveredFiles)
+      Printf("UNCOVERED_FILE: %s\n", File.c_str());
+  }
+}
+
+void TracePC::DumpCoverage() {
+  __sanitizer_dump_coverage(PCs, GetNumPCs());
+}
+
+// Value profile.
+// We keep track of various values that affect control flow.
+// These values are inserted into a bit-set-based hash map.
+// Every new bit in the map is treated as a new coverage.
+//
+// For memcmp/strcmp/etc the interesting value is the length of the common
+// prefix of the parameters.
+// For cmp instructions the interesting value is a XOR of the parameters.
+// The interesting value is mixed up with the PC and is then added to the map.
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void TracePC::AddValueForMemcmp(void *caller_pc, const void *s1, const void *s2,
+                              size_t n) {
+  if (!n) return;
+  size_t Len = std::min(n, (size_t)32);
+  const uint8_t *A1 = reinterpret_cast<const uint8_t *>(s1);
+  const uint8_t *A2 = reinterpret_cast<const uint8_t *>(s2);
+  size_t I = 0;
+  for (; I < Len; I++)
+    if (A1[I] != A2[I])
+      break;
+  size_t PC = reinterpret_cast<size_t>(caller_pc);
+  size_t Idx = I;
+  // if (I < Len)
+  //  Idx += __builtin_popcountl((A1[I] ^ A2[I])) - 1;
+  TPC.HandleValueProfile((PC & 4095) | (Idx << 12));
+}
+
+ATTRIBUTE_NO_SANITIZE_MEMORY
+void TracePC::AddValueForStrcmp(void *caller_pc, const char *s1, const char *s2,
+                              size_t n) {
+  if (!n) return;
+  size_t Len = std::min(n, (size_t)32);
+  const uint8_t *A1 = reinterpret_cast<const uint8_t *>(s1);
+  const uint8_t *A2 = reinterpret_cast<const uint8_t *>(s2);
+  size_t I = 0;
+  for (; I < Len; I++)
+    if (A1[I] != A2[I] || A1[I] == 0)
+      break;
+  size_t PC = reinterpret_cast<size_t>(caller_pc);
+  size_t Idx = I;
+  // if (I < Len && A1[I])
+  //  Idx += __builtin_popcountl((A1[I] ^ A2[I])) - 1;
+  TPC.HandleValueProfile((PC & 4095) | (Idx << 12));
+}
+
+template <class T>
+ATTRIBUTE_TARGET_POPCNT
+#ifdef __clang__  // g++ can't handle this __attribute__ here :(
+__attribute__((always_inline))
+#endif  // __clang__
+void TracePC::HandleCmp(void *PC, T Arg1, T Arg2) {
+  uintptr_t PCuint = reinterpret_cast<uintptr_t>(PC);
+  uint64_t ArgXor = Arg1 ^ Arg2;
+  uint64_t ArgDistance = __builtin_popcountl(ArgXor) + 1; // [1,65]
+  uintptr_t Idx = ((PCuint & 4095) + 1) * ArgDistance;
+  if (sizeof(T) == 4)
+      TORC4.Insert(ArgXor, Arg1, Arg2);
+  else if (sizeof(T) == 8)
+      TORC8.Insert(ArgXor, Arg1, Arg2);
+  HandleValueProfile(Idx);
+}
+
+} // namespace fuzzer
+
+extern "C" {
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_pc_guard(uint32_t *Guard) {
+  uintptr_t PC = (uintptr_t)__builtin_return_address(0);
+  fuzzer::TPC.HandleTrace(Guard, PC);
+}
+
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_pc_guard_init(uint32_t *Start, uint32_t *Stop) {
+  fuzzer::TPC.HandleInit(Start, Stop);
+}
+
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_pc_indir(uintptr_t Callee) {
+  uintptr_t PC = (uintptr_t)__builtin_return_address(0);
+  fuzzer::TPC.HandleCallerCallee(PC, Callee);
+}
+
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Arg1, Arg2);
+}
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Arg1, Arg2);
+}
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Arg1, Arg2);
+}
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Arg1, Arg2);
+}
+
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t *Cases) {
+  // Updates the value profile based on the relative position of Val and Cases.
+  // We want to handle one random case at every call (handling all is slow).
+  // Since none of the arguments contain any random bits we use a thread-local
+  // counter to choose the random case to handle.
+  static thread_local size_t Counter;
+  Counter++;
+  uint64_t N = Cases[0];
+  uint64_t *Vals = Cases + 2;
+  char *PC = (char*)__builtin_return_address(0);
+  // We need a random number < N using Counter as a seed. But w/o DIV.
+  // * find a power of two >= N
+  // * mask Counter with this power of two.
+  // * maybe subtract N.
+  size_t Nlog = sizeof(long) * 8 - __builtin_clzl((long)N);
+  size_t PowerOfTwoGeN = 1U << Nlog;
+  assert(PowerOfTwoGeN >= N);
+  size_t Idx = Counter & (PowerOfTwoGeN - 1);
+  if (Idx >= N)
+    Idx -= N;
+  assert(Idx < N);
+  uint64_t TwoIn32 = 1ULL << 32;
+  if ((Val | Vals[Idx]) < TwoIn32)
+    fuzzer::TPC.HandleCmp(PC + Idx, static_cast<uint32_t>(Val),
+                          static_cast<uint32_t>(Vals[Idx]));
+  else
+    fuzzer::TPC.HandleCmp(PC + Idx, Val, Vals[Idx]);
+}
+
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_div4(uint32_t Val) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Val, (uint32_t)0);
+}
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_div8(uint64_t Val) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Val, (uint64_t)0);
+}
+__attribute__((visibility("default")))
+void __sanitizer_cov_trace_gep(uintptr_t Idx) {
+  fuzzer::TPC.HandleCmp(__builtin_return_address(0), Idx, (uintptr_t)0);
+}
+
+}  // extern "C"

test/fuzz_test/Fuzzer/FuzzerTracePC.h

@@ -0,0 +1,158 @@
+//===- FuzzerTracePC.h - Internal header for the Fuzzer ---------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// fuzzer::TracePC
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_TRACE_PC
+#define LLVM_FUZZER_TRACE_PC
+
+#include "FuzzerDefs.h"
+#include "FuzzerValueBitMap.h"
+#include <set>
+
+namespace fuzzer {
+
+// TableOfRecentCompares (TORC) remembers the most recently performed
+// comparisons of type T.
+// We record the arguments of CMP instructions in this table unconditionally
+// because it seems cheaper this way than to compute some expensive
+// conditions inside __sanitizer_cov_trace_cmp*.
+// After the unit has been executed we may decide to use the contents of
+// this table to populate a Dictionary.
+template<class T, size_t kSizeT>
+struct TableOfRecentCompares {
+  static const size_t kSize = kSizeT;
+  struct Pair {
+    T A, B;
+  };
+  void Insert(size_t Idx, T Arg1, T Arg2) {
+    Idx = Idx % kSize;
+    Table[Idx].A = Arg1;
+    Table[Idx].B = Arg2;
+  }
+
+  Pair Get(size_t I) { return Table[I % kSize]; }
+
+  Pair Table[kSize];
+};
+
+class TracePC {
+ public:
+  static const size_t kFeatureSetSize = ValueBitMap::kNumberOfItems;
+
+  void HandleTrace(uint32_t *guard, uintptr_t PC);
+  void HandleInit(uint32_t *start, uint32_t *stop);
+  void HandleCallerCallee(uintptr_t Caller, uintptr_t Callee);
+  void HandleValueProfile(size_t Value) { ValueProfileMap.AddValue(Value); }
+  template <class T> void HandleCmp(void *PC, T Arg1, T Arg2);
+  size_t GetTotalPCCoverage();
+  void SetUseCounters(bool UC) { UseCounters = UC; }
+  void SetUseValueProfile(bool VP) { UseValueProfile = VP; }
+  void SetPrintNewPCs(bool P) { DoPrintNewPCs = P; }
+  template <class Callback> size_t CollectFeatures(Callback CB);
+  bool UpdateValueProfileMap(ValueBitMap *MaxValueProfileMap) {
+    return UseValueProfile && MaxValueProfileMap->MergeFrom(ValueProfileMap);
+  }
+
+  void ResetMaps() {
+    ValueProfileMap.Reset();
+    memset(Counters, 0, sizeof(Counters));
+  }
+
+  void UpdateFeatureSet(size_t CurrentElementIdx, size_t CurrentElementSize);
+  void PrintFeatureSet();
+
+  void PrintModuleInfo();
+
+  void PrintCoverage();
+  void DumpCoverage();
+
+  void AddValueForMemcmp(void *caller_pc, const void *s1, const void *s2,
+                         size_t n);
+  void AddValueForStrcmp(void *caller_pc, const char *s1, const char *s2,
+                         size_t n);
+
+  bool UsingTracePcGuard() const {return NumModules; }
+
+  static const size_t kTORCSize = 1 << 5;
+  TableOfRecentCompares<uint32_t, kTORCSize> TORC4;
+  TableOfRecentCompares<uint64_t, kTORCSize> TORC8;
+
+  void PrintNewPCs();
+  size_t GetNumPCs() const { return Min(kNumPCs, NumGuards + 1); }
+  uintptr_t GetPC(size_t Idx) {
+    assert(Idx < GetNumPCs());
+    return PCs[Idx];
+  }
+
+private:
+  bool UseCounters = false;
+  bool UseValueProfile = false;
+  bool DoPrintNewPCs = false;
+
+  struct Module {
+    uint32_t *Start, *Stop;
+  };
+
+  Module Modules[4096];
+  size_t NumModules;  // linker-initialized.
+  size_t NumGuards;  // linker-initialized.
+
+  static const size_t kNumCounters = 1 << 14;
+  alignas(8) uint8_t Counters[kNumCounters];
+
+  static const size_t kNumPCs = 1 << 24;
+  uintptr_t PCs[kNumPCs];
+
+  std::set<uintptr_t> *PrintedPCs;
+
+  ValueBitMap ValueProfileMap;
+};
+
+template <class Callback>
+size_t TracePC::CollectFeatures(Callback CB) {
+  if (!UsingTracePcGuard()) return 0;
+  size_t Res = 0;
+  const size_t Step = 8;
+  assert(reinterpret_cast<uintptr_t>(Counters) % Step == 0);
+  size_t N = Min(kNumCounters, NumGuards + 1);
+  N = (N + Step - 1) & ~(Step - 1);  // Round up.
+  for (size_t Idx = 0; Idx < N; Idx += Step) {
+    uint64_t Bundle = *reinterpret_cast<uint64_t*>(&Counters[Idx]);
+    if (!Bundle) continue;
+    for (size_t i = Idx; i < Idx + Step; i++) {
+      uint8_t Counter = (Bundle >> ((i - Idx) * 8)) & 0xff;
+      if (!Counter) continue;
+      Counters[i] = 0;
+      unsigned Bit = 0;
+      /**/ if (Counter >= 128) Bit = 7;
+      else if (Counter >= 32) Bit = 6;
+      else if (Counter >= 16) Bit = 5;
+      else if (Counter >= 8) Bit = 4;
+      else if (Counter >= 4) Bit = 3;
+      else if (Counter >= 3) Bit = 2;
+      else if (Counter >= 2) Bit = 1;
+      size_t Feature = (i * 8 + Bit);
+      if (CB(Feature))
+        Res++;
+    }
+  }
+  if (UseValueProfile)
+    ValueProfileMap.ForEach([&](size_t Idx) {
+      if (CB(NumGuards * 8 + Idx))
+        Res++;
+    });
+  return Res;
+}
+
+extern TracePC TPC;
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_TRACE_PC

test/fuzz_test/Fuzzer/FuzzerTraceState.cpp

@@ -0,0 +1,325 @@
+//===- FuzzerTraceState.cpp - Trace-based fuzzer mutator ------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Data tracing.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerDictionary.h"
+#include "FuzzerInternal.h"
+#include "FuzzerIO.h"
+#include "FuzzerMutate.h"
+#include "FuzzerRandom.h"
+#include "FuzzerTracePC.h"
+#include <algorithm>
+#include <cstring>
+#include <map>
+#include <set>
+#include <thread>
+
+namespace fuzzer {
+
+// For now, very simple: put Size bytes of Data at position Pos.
+struct TraceBasedMutation {
+  uint32_t Pos;
+  Word W;
+};
+
+// Declared as static globals for faster checks inside the hooks.
+static bool RecordingMemcmp = false;
+static bool RecordingMemmem = false;
+static bool DoingMyOwnMemmem = false;
+
+ScopedDoingMyOwnMemmem::ScopedDoingMyOwnMemmem() { DoingMyOwnMemmem = true; }
+ScopedDoingMyOwnMemmem::~ScopedDoingMyOwnMemmem() { DoingMyOwnMemmem = false; }
+
+class TraceState {
+public:
+  TraceState(MutationDispatcher &MD, const FuzzingOptions &Options,
+             const Fuzzer *F)
+      : MD(MD), Options(Options), F(F) {}
+
+  void TraceMemcmpCallback(size_t CmpSize, const uint8_t *Data1,
+                           const uint8_t *Data2);
+
+  void TraceSwitchCallback(uintptr_t PC, size_t ValSizeInBits, uint64_t Val,
+                           size_t NumCases, uint64_t *Cases);
+  int TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
+                          size_t DataSize);
+  int TryToAddDesiredData(const uint8_t *PresentData,
+                          const uint8_t *DesiredData, size_t DataSize);
+
+  void StartTraceRecording() {
+    if (!Options.UseMemcmp)
+      return;
+    RecordingMemcmp = Options.UseMemcmp;
+    RecordingMemmem = Options.UseMemmem;
+    NumMutations = 0;
+    InterestingWords.clear();
+    MD.ClearAutoDictionary();
+  }
+
+  void StopTraceRecording() {
+    if (!RecordingMemcmp)
+      return;
+    RecordingMemcmp = false;
+    for (size_t i = 0; i < NumMutations; i++) {
+      auto &M = Mutations[i];
+      if (Options.Verbosity >= 2) {
+        AutoDictUnitCounts[M.W]++;
+        AutoDictAdds++;
+        if ((AutoDictAdds & (AutoDictAdds - 1)) == 0) {
+          typedef std::pair<size_t, Word> CU;
+          std::vector<CU> CountedUnits;
+          for (auto &I : AutoDictUnitCounts)
+            CountedUnits.push_back(std::make_pair(I.second, I.first));
+          std::sort(CountedUnits.begin(), CountedUnits.end(),
+                    [](const CU &a, const CU &b) { return a.first > b.first; });
+          Printf("AutoDict:\n");
+          for (auto &I : CountedUnits) {
+            Printf("   %zd ", I.first);
+            PrintASCII(I.second.data(), I.second.size());
+            Printf("\n");
+          }
+        }
+      }
+      MD.AddWordToAutoDictionary({M.W, M.Pos});
+    }
+    for (auto &W : InterestingWords)
+      MD.AddWordToAutoDictionary({W});
+  }
+
+  void AddMutation(uint32_t Pos, uint32_t Size, const uint8_t *Data) {
+    if (NumMutations >= kMaxMutations) return;
+    auto &M = Mutations[NumMutations++];
+    M.Pos = Pos;
+    M.W.Set(Data, Size);
+  }
+
+  void AddMutation(uint32_t Pos, uint32_t Size, uint64_t Data) {
+    assert(Size <= sizeof(Data));
+    AddMutation(Pos, Size, reinterpret_cast<uint8_t*>(&Data));
+  }
+
+  void AddInterestingWord(const uint8_t *Data, size_t Size) {
+    if (!RecordingMemmem || !F->InFuzzingThread()) return;
+    if (Size <= 1) return;
+    Size = std::min(Size, Word::GetMaxSize());
+    Word W(Data, Size);
+    InterestingWords.insert(W);
+  }
+
+ private:
+  bool IsTwoByteData(uint64_t Data) {
+    int64_t Signed = static_cast<int64_t>(Data);
+    Signed >>= 16;
+    return Signed == 0 || Signed == -1L;
+  }
+
+  // We don't want to create too many trace-based mutations as it is both
+  // expensive and useless. So after some number of mutations is collected,
+  // start rejecting some of them. The more there are mutations the more we
+  // reject.
+  bool WantToHandleOneMoreMutation() {
+    const size_t FirstN = 64;
+    // Gladly handle first N mutations.
+    if (NumMutations <= FirstN) return true;
+    size_t Diff = NumMutations - FirstN;
+    size_t DiffLog = sizeof(long) * 8 - __builtin_clzl((long)Diff);
+    assert(DiffLog > 0 && DiffLog < 64);
+    bool WantThisOne = MD.GetRand()(1 << DiffLog) == 0;  // 1 out of DiffLog.
+    return WantThisOne;
+  }
+
+  static const size_t kMaxMutations = 1 << 16;
+  size_t NumMutations;
+  TraceBasedMutation Mutations[kMaxMutations];
+  // TODO: std::set is too inefficient, need to have a custom DS here.
+  std::set<Word> InterestingWords;
+  MutationDispatcher &MD;
+  const FuzzingOptions Options;
+  const Fuzzer *F;
+  std::map<Word, size_t> AutoDictUnitCounts;
+  size_t AutoDictAdds = 0;
+};
+
+int TraceState::TryToAddDesiredData(uint64_t PresentData, uint64_t DesiredData,
+                                    size_t DataSize) {
+  if (NumMutations >= kMaxMutations || !WantToHandleOneMoreMutation()) return 0;
+  ScopedDoingMyOwnMemmem scoped_doing_my_own_memmem;
+  const uint8_t *UnitData;
+  auto UnitSize = F->GetCurrentUnitInFuzzingThead(&UnitData);
+  int Res = 0;
+  const uint8_t *Beg = UnitData;
+  const uint8_t *End = Beg + UnitSize;
+  for (const uint8_t *Cur = Beg; Cur < End; Cur++) {
+    Cur = (uint8_t *)SearchMemory(Cur, End - Cur, &PresentData, DataSize);
+    if (!Cur)
+      break;
+    size_t Pos = Cur - Beg;
+    assert(Pos < UnitSize);
+    AddMutation(Pos, DataSize, DesiredData);
+    AddMutation(Pos, DataSize, DesiredData + 1);
+    AddMutation(Pos, DataSize, DesiredData - 1);
+    Res++;
+  }
+  return Res;
+}
+
+int TraceState::TryToAddDesiredData(const uint8_t *PresentData,
+                                    const uint8_t *DesiredData,
+                                    size_t DataSize) {
+  if (NumMutations >= kMaxMutations || !WantToHandleOneMoreMutation()) return 0;
+  ScopedDoingMyOwnMemmem scoped_doing_my_own_memmem;
+  const uint8_t *UnitData;
+  auto UnitSize = F->GetCurrentUnitInFuzzingThead(&UnitData);
+  int Res = 0;
+  const uint8_t *Beg = UnitData;
+  const uint8_t *End = Beg + UnitSize;
+  for (const uint8_t *Cur = Beg; Cur < End; Cur++) {
+    Cur = (uint8_t *)SearchMemory(Cur, End - Cur, PresentData, DataSize);
+    if (!Cur)
+      break;
+    size_t Pos = Cur - Beg;
+    assert(Pos < UnitSize);
+    AddMutation(Pos, DataSize, DesiredData);
+    Res++;
+  }
+  return Res;
+}
+
+void TraceState::TraceMemcmpCallback(size_t CmpSize, const uint8_t *Data1,
+                                     const uint8_t *Data2) {
+  if (!RecordingMemcmp || !F->InFuzzingThread()) return;
+  CmpSize = std::min(CmpSize, Word::GetMaxSize());
+  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) PrintASCII(Data1, CmpSize);
+    if (Added2) PrintASCII(Data2, CmpSize);
+    Printf("\n");
+  }
+}
+
+void TraceState::TraceSwitchCallback(uintptr_t PC, size_t ValSizeInBits,
+                                     uint64_t Val, size_t NumCases,
+                                     uint64_t *Cases) {
+  if (F->InFuzzingThread()) return;
+  size_t ValSize = ValSizeInBits / 8;
+  bool TryShort = IsTwoByteData(Val);
+  for (size_t i = 0; i < NumCases; i++)
+    TryShort &= IsTwoByteData(Cases[i]);
+
+  if (Options.Verbosity >= 3)
+    Printf("TraceSwitch: %p %zd # %zd; TryShort %d\n", PC, Val, NumCases,
+           TryShort);
+
+  for (size_t i = 0; i < NumCases; i++) {
+    TryToAddDesiredData(Val, Cases[i], ValSize);
+    if (TryShort)
+      TryToAddDesiredData(Val, Cases[i], 2);
+  }
+}
+
+static TraceState *TS;
+
+void Fuzzer::StartTraceRecording() {
+  if (!TS) return;
+  TS->StartTraceRecording();
+}
+
+void Fuzzer::StopTraceRecording() {
+  if (!TS) return;
+  TS->StopTraceRecording();
+}
+
+void Fuzzer::InitializeTraceState() {
+  if (!Options.UseMemcmp) return;
+  TS = new TraceState(MD, Options, this);
+}
+
+static size_t InternalStrnlen(const char *S, size_t MaxLen) {
+  size_t Len = 0;
+  for (; Len < MaxLen && S[Len]; Len++) {}
+  return Len;
+}
+
+}  // namespace fuzzer
+
+using fuzzer::TS;
+using fuzzer::RecordingMemcmp;
+
+extern "C" {
+
+// We may need to avoid defining weak hooks to stay compatible with older clang.
+#ifndef LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
+# define LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS 1
+#endif
+
+#if LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
+void __sanitizer_weak_hook_memcmp(void *caller_pc, const void *s1,
+                                  const void *s2, size_t n, int result) {
+  fuzzer::TPC.AddValueForMemcmp(caller_pc, s1, s2, n);
+  if (!RecordingMemcmp) return;
+  if (result == 0) return;  // No reason to mutate.
+  if (n <= 1) return;  // Not interesting.
+  TS->TraceMemcmpCallback(n, reinterpret_cast<const uint8_t *>(s1),
+                          reinterpret_cast<const uint8_t *>(s2));
+}
+
+void __sanitizer_weak_hook_strncmp(void *caller_pc, const char *s1,
+                                   const char *s2, size_t n, int result) {
+  fuzzer::TPC.AddValueForStrcmp(caller_pc, s1, s2, n);
+  if (!RecordingMemcmp) return;
+  if (result == 0) return;  // No reason to mutate.
+  size_t Len1 = fuzzer::InternalStrnlen(s1, n);
+  size_t Len2 = fuzzer::InternalStrnlen(s2, n);
+  n = std::min(n, Len1);
+  n = std::min(n, Len2);
+  if (n <= 1) return;  // Not interesting.
+  TS->TraceMemcmpCallback(n, reinterpret_cast<const uint8_t *>(s1),
+                          reinterpret_cast<const uint8_t *>(s2));
+}
+
+void __sanitizer_weak_hook_strcmp(void *caller_pc, const char *s1,
+                                   const char *s2, int result) {
+  fuzzer::TPC.AddValueForStrcmp(caller_pc, s1, s2, 64);
+  if (!RecordingMemcmp) return;
+  if (result == 0) return;  // No reason to mutate.
+  size_t Len1 = strlen(s1);
+  size_t Len2 = strlen(s2);
+  size_t N = std::min(Len1, Len2);
+  if (N <= 1) return;  // Not interesting.
+  TS->TraceMemcmpCallback(N, reinterpret_cast<const uint8_t *>(s1),
+                          reinterpret_cast<const uint8_t *>(s2));
+}
+
+void __sanitizer_weak_hook_strncasecmp(void *called_pc, const char *s1,
+                                       const char *s2, size_t n, int result) {
+  return __sanitizer_weak_hook_strncmp(called_pc, s1, s2, n, result);
+}
+void __sanitizer_weak_hook_strcasecmp(void *called_pc, const char *s1,
+                                      const char *s2, int result) {
+  return __sanitizer_weak_hook_strcmp(called_pc, s1, s2, result);
+}
+void __sanitizer_weak_hook_strstr(void *called_pc, const char *s1,
+                                  const char *s2, char *result) {
+  TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
+}
+void __sanitizer_weak_hook_strcasestr(void *called_pc, const char *s1,
+                                      const char *s2, char *result) {
+  TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
+}
+void __sanitizer_weak_hook_memmem(void *called_pc, const void *s1, size_t len1,
+                                  const void *s2, size_t len2, void *result) {
+  if (fuzzer::DoingMyOwnMemmem) return;
+  TS->AddInterestingWord(reinterpret_cast<const uint8_t *>(s2), len2);
+}
+
+#endif  // LLVM_FUZZER_DEFINES_SANITIZER_WEAK_HOOOKS
+}  // extern "C"

test/fuzz_test/Fuzzer/FuzzerUtil.cpp

@@ -0,0 +1,218 @@
+//===- FuzzerUtil.cpp - Misc utils ----------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Misc utils.
+//===----------------------------------------------------------------------===//
+
+#include "FuzzerUtil.h"
+#include "FuzzerIO.h"
+#include "FuzzerInternal.h"
+#include <cassert>
+#include <chrono>
+#include <cstring>
+#include <errno.h>
+#include <signal.h>
+#include <sstream>
+#include <stdio.h>
+#include <sys/types.h>
+#include <thread>
+
+namespace fuzzer {
+
+void PrintHexArray(const uint8_t *Data, size_t Size,
+                   const char *PrintAfter) {
+  for (size_t i = 0; i < Size; i++)
+    Printf("0x%x,", (unsigned)Data[i]);
+  Printf("%s", PrintAfter);
+}
+
+void Print(const Unit &v, const char *PrintAfter) {
+  PrintHexArray(v.data(), v.size(), PrintAfter);
+}
+
+void PrintASCIIByte(uint8_t Byte) {
+  if (Byte == '\\')
+    Printf("\\\\");
+  else if (Byte == '"')
+    Printf("\\\"");
+  else if (Byte >= 32 && Byte < 127)
+    Printf("%c", Byte);
+  else
+    Printf("\\x%02x", Byte);
+}
+
+void PrintASCII(const uint8_t *Data, size_t Size, const char *PrintAfter) {
+  for (size_t i = 0; i < Size; i++)
+    PrintASCIIByte(Data[i]);
+  Printf("%s", PrintAfter);
+}
+
+void PrintASCII(const Unit &U, const char *PrintAfter) {
+  PrintASCII(U.data(), U.size(), PrintAfter);
+}
+
+bool ToASCII(uint8_t *Data, size_t Size) {
+  bool Changed = false;
+  for (size_t i = 0; i < Size; i++) {
+    uint8_t &X = Data[i];
+    auto NewX = X;
+    NewX &= 127;
+    if (!isspace(NewX) && !isprint(NewX))
+      NewX = ' ';
+    Changed |= NewX != X;
+    X = NewX;
+  }
+  return Changed;
+}
+
+bool IsASCII(const Unit &U) { return IsASCII(U.data(), U.size()); }
+
+bool IsASCII(const uint8_t *Data, size_t Size) {
+  for (size_t i = 0; i < Size; i++)
+    if (!(isprint(Data[i]) || isspace(Data[i]))) return false;
+  return true;
+}
+
+bool ParseOneDictionaryEntry(const std::string &Str, Unit *U) {
+  U->clear();
+  if (Str.empty()) return false;
+  size_t L = 0, R = Str.size() - 1;  // We are parsing the range [L,R].
+  // Skip spaces from both sides.
+  while (L < R && isspace(Str[L])) L++;
+  while (R > L && isspace(Str[R])) R--;
+  if (R - L < 2) return false;
+  // Check the closing "
+  if (Str[R] != '"') return false;
+  R--;
+  // Find the opening "
+  while (L < R && Str[L] != '"') L++;
+  if (L >= R) return false;
+  assert(Str[L] == '\"');
+  L++;
+  assert(L <= R);
+  for (size_t Pos = L; Pos <= R; Pos++) {
+    uint8_t V = (uint8_t)Str[Pos];
+    if (!isprint(V) && !isspace(V)) return false;
+    if (V =='\\') {
+      // Handle '\\'
+      if (Pos + 1 <= R && (Str[Pos + 1] == '\\' || Str[Pos + 1] == '"')) {
+        U->push_back(Str[Pos + 1]);
+        Pos++;
+        continue;
+      }
+      // Handle '\xAB'
+      if (Pos + 3 <= R && Str[Pos + 1] == 'x'
+           && isxdigit(Str[Pos + 2]) && isxdigit(Str[Pos + 3])) {
+        char Hex[] = "0xAA";
+        Hex[2] = Str[Pos + 2];
+        Hex[3] = Str[Pos + 3];
+        U->push_back(strtol(Hex, nullptr, 16));
+        Pos += 3;
+        continue;
+      }
+      return false;  // Invalid escape.
+    } else {
+      // Any other character.
+      U->push_back(V);
+    }
+  }
+  return true;
+}
+
+bool ParseDictionaryFile(const std::string &Text, std::vector<Unit> *Units) {
+  if (Text.empty()) {
+    Printf("ParseDictionaryFile: file does not exist or is empty\n");
+    return false;
+  }
+  std::istringstream ISS(Text);
+  Units->clear();
+  Unit U;
+  int LineNo = 0;
+  std::string S;
+  while (std::getline(ISS, S, '\n')) {
+    LineNo++;
+    size_t Pos = 0;
+    while (Pos < S.size() && isspace(S[Pos])) Pos++;  // Skip spaces.
+    if (Pos == S.size()) continue;  // Empty line.
+    if (S[Pos] == '#') continue;  // Comment line.
+    if (ParseOneDictionaryEntry(S, &U)) {
+      Units->push_back(U);
+    } else {
+      Printf("ParseDictionaryFile: error in line %d\n\t\t%s\n", LineNo,
+             S.c_str());
+      return false;
+    }
+  }
+  return true;
+}
+
+std::string Base64(const Unit &U) {
+  static const char Table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                              "abcdefghijklmnopqrstuvwxyz"
+                              "0123456789+/";
+  std::string Res;
+  size_t i;
+  for (i = 0; i + 2 < U.size(); i += 3) {
+    uint32_t x = (U[i] << 16) + (U[i + 1] << 8) + U[i + 2];
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += Table[(x >> 6) & 63];
+    Res += Table[x & 63];
+  }
+  if (i + 1 == U.size()) {
+    uint32_t x = (U[i] << 16);
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += "==";
+  } else if (i + 2 == U.size()) {
+    uint32_t x = (U[i] << 16) + (U[i + 1] << 8);
+    Res += Table[(x >> 18) & 63];
+    Res += Table[(x >> 12) & 63];
+    Res += Table[(x >> 6) & 63];
+    Res += "=";
+  }
+  return Res;
+}
+
+std::string DescribePC(const char *SymbolizedFMT, uintptr_t PC) {
+  if (!EF->__sanitizer_symbolize_pc) return "<can not symbolize>";
+  char PcDescr[1024];
+  EF->__sanitizer_symbolize_pc(reinterpret_cast<void*>(PC),
+                               SymbolizedFMT, PcDescr, sizeof(PcDescr));
+  PcDescr[sizeof(PcDescr) - 1] = 0;  // Just in case.
+  return PcDescr;
+}
+
+void PrintPC(const char *SymbolizedFMT, const char *FallbackFMT, uintptr_t PC) {
+  if (EF->__sanitizer_symbolize_pc)
+    Printf("%s", DescribePC(SymbolizedFMT, PC).c_str());
+  else
+    Printf(FallbackFMT, PC);
+}
+
+unsigned NumberOfCpuCores() {
+  unsigned N = std::thread::hardware_concurrency();
+  if (!N) {
+    Printf("WARNING: std::thread::hardware_concurrency not well defined for "
+           "your platform. Assuming CPU count of 1.\n");
+    N = 1;
+  }
+  return N;
+}
+
+bool ExecuteCommandAndReadOutput(const std::string &Command, std::string *Out) {
+  FILE *Pipe = OpenProcessPipe(Command.c_str(), "r");
+  if (!Pipe) return false;
+  char Buff[1024];
+  size_t N;
+  while ((N = fread(Buff, 1, sizeof(Buff), Pipe)) > 0)
+    Out->append(Buff, N);
+  return true;
+}
+
+}  // namespace fuzzer

test/fuzz_test/Fuzzer/FuzzerUtil.h

@@ -0,0 +1,72 @@
+//===- FuzzerUtil.h - Internal header for the Fuzzer Utils ------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Util functions.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_UTIL_H
+#define LLVM_FUZZER_UTIL_H
+
+#include "FuzzerDefs.h"
+
+namespace fuzzer {
+
+void PrintHexArray(const Unit &U, const char *PrintAfter = "");
+
+void PrintHexArray(const uint8_t *Data, size_t Size,
+                   const char *PrintAfter = "");
+
+void PrintASCII(const uint8_t *Data, size_t Size, const char *PrintAfter = "");
+
+void PrintASCII(const Unit &U, const char *PrintAfter = "");
+
+// Changes U to contain only ASCII (isprint+isspace) characters.
+// Returns true iff U has been changed.
+bool ToASCII(uint8_t *Data, size_t Size);
+
+bool IsASCII(const Unit &U);
+
+bool IsASCII(const uint8_t *Data, size_t Size);
+
+std::string Base64(const Unit &U);
+
+void PrintPC(const char *SymbolizedFMT, const char *FallbackFMT, uintptr_t PC);
+
+std::string DescribePC(const char *SymbolizedFMT, uintptr_t PC);
+
+unsigned NumberOfCpuCores();
+
+bool ExecuteCommandAndReadOutput(const std::string &Command, std::string *Out);
+
+// Platform specific functions.
+void SetSignalHandler(const FuzzingOptions& Options);
+
+void SleepSeconds(int Seconds);
+
+unsigned long GetPid();
+
+size_t GetPeakRSSMb();
+
+int ExecuteCommand(const std::string &Command);
+
+FILE *OpenProcessPipe(const char *Command, const char *Mode);
+
+const void *SearchMemory(const void *haystack, size_t haystacklen,
+                         const void *needle, size_t needlelen);
+
+std::string CloneArgsWithoutX(const std::vector<std::string> &Args,
+                              const char *X1, const char *X2);
+
+inline std::string CloneArgsWithoutX(const std::vector<std::string> &Args,
+                                     const char *X) {
+  return CloneArgsWithoutX(Args, X, X);
+}
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_UTIL_H

test/fuzz_test/Fuzzer/FuzzerUtilDarwin.cpp

@@ -0,0 +1,152 @@
+//===- FuzzerUtilDarwin.cpp - Misc utils ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Misc utils for Darwin.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_APPLE
+
+#include "FuzzerIO.h"
+#include <mutex>
+#include <signal.h>
+#include <spawn.h>
+#include <sys/wait.h>
+
+// There is no header for this on macOS so declare here
+extern "C" char **environ;
+
+namespace fuzzer {
+
+static std::mutex SignalMutex;
+// Global variables used to keep track of how signal handling should be
+// restored. They should **not** be accessed without holding `SignalMutex`.
+static int ActiveThreadCount = 0;
+static struct sigaction OldSigIntAction;
+static struct sigaction OldSigQuitAction;
+static sigset_t OldBlockedSignalsSet;
+
+// This is a reimplementation of Libc's `system()`. On Darwin the Libc
+// implementation contains a mutex which prevents it from being used
+// concurrently. This implementation **can** be used concurrently. It sets the
+// signal handlers when the first thread enters and restores them when the last
+// thread finishes execution of the function and ensures this is not racey by
+// using a mutex.
+int ExecuteCommand(const std::string &Command) {
+  posix_spawnattr_t SpawnAttributes;
+  if (posix_spawnattr_init(&SpawnAttributes))
+    return -1;
+  // Block and ignore signals of the current process when the first thread
+  // enters.
+  {
+    std::lock_guard<std::mutex> Lock(SignalMutex);
+    if (ActiveThreadCount == 0) {
+      static struct sigaction IgnoreSignalAction;
+      sigset_t BlockedSignalsSet;
+      memset(&IgnoreSignalAction, 0, sizeof(IgnoreSignalAction));
+      IgnoreSignalAction.sa_handler = SIG_IGN;
+
+      if (sigaction(SIGINT, &IgnoreSignalAction, &OldSigIntAction) == -1) {
+        Printf("Failed to ignore SIGINT\n");
+        (void)posix_spawnattr_destroy(&SpawnAttributes);
+        return -1;
+      }
+      if (sigaction(SIGQUIT, &IgnoreSignalAction, &OldSigQuitAction) == -1) {
+        Printf("Failed to ignore SIGQUIT\n");
+        // Try our best to restore the signal handlers.
+        (void)sigaction(SIGINT, &OldSigIntAction, NULL);
+        (void)posix_spawnattr_destroy(&SpawnAttributes);
+        return -1;
+      }
+
+      (void)sigemptyset(&BlockedSignalsSet);
+      (void)sigaddset(&BlockedSignalsSet, SIGCHLD);
+      if (sigprocmask(SIG_BLOCK, &BlockedSignalsSet, &OldBlockedSignalsSet) ==
+          -1) {
+        Printf("Failed to block SIGCHLD\n");
+        // Try our best to restore the signal handlers.
+        (void)sigaction(SIGQUIT, &OldSigQuitAction, NULL);
+        (void)sigaction(SIGINT, &OldSigIntAction, NULL);
+        (void)posix_spawnattr_destroy(&SpawnAttributes);
+        return -1;
+      }
+    }
+    ++ActiveThreadCount;
+  }
+
+  // NOTE: Do not introduce any new `return` statements past this
+  // point. It is important that `ActiveThreadCount` always be decremented
+  // when leaving this function.
+
+  // Make sure the child process uses the default handlers for the
+  // following signals rather than inheriting what the parent has.
+  sigset_t DefaultSigSet;
+  (void)sigemptyset(&DefaultSigSet);
+  (void)sigaddset(&DefaultSigSet, SIGQUIT);
+  (void)sigaddset(&DefaultSigSet, SIGINT);
+  (void)posix_spawnattr_setsigdefault(&SpawnAttributes, &DefaultSigSet);
+  // Make sure the child process doesn't block SIGCHLD
+  (void)posix_spawnattr_setsigmask(&SpawnAttributes, &OldBlockedSignalsSet);
+  short SpawnFlags = POSIX_SPAWN_SETSIGDEF | POSIX_SPAWN_SETSIGMASK;
+  (void)posix_spawnattr_setflags(&SpawnAttributes, SpawnFlags);
+
+  pid_t Pid;
+  char **Environ = environ; // Read from global
+  const char *CommandCStr = Command.c_str();
+  const char *Argv[] = {"sh", "-c", CommandCStr, NULL};
+  int ErrorCode = 0, ProcessStatus = 0;
+  // FIXME: We probably shouldn't hardcode the shell path.
+  ErrorCode = posix_spawn(&Pid, "/bin/sh", NULL, &SpawnAttributes,
+                          (char *const *)Argv, Environ);
+  (void)posix_spawnattr_destroy(&SpawnAttributes);
+  if (!ErrorCode) {
+    pid_t SavedPid = Pid;
+    do {
+      // Repeat until call completes uninterrupted.
+      Pid = waitpid(SavedPid, &ProcessStatus, /*options=*/0);
+    } while (Pid == -1 && errno == EINTR);
+    if (Pid == -1) {
+      // Fail for some other reason.
+      ProcessStatus = -1;
+    }
+  } else if (ErrorCode == ENOMEM || ErrorCode == EAGAIN) {
+    // Fork failure.
+    ProcessStatus = -1;
+  } else {
+    // Shell execution failure.
+    ProcessStatus = W_EXITCODE(127, 0);
+  }
+
+  // Restore the signal handlers of the current process when the last thread
+  // using this function finishes.
+  {
+    std::lock_guard<std::mutex> Lock(SignalMutex);
+    --ActiveThreadCount;
+    if (ActiveThreadCount == 0) {
+      bool FailedRestore = false;
+      if (sigaction(SIGINT, &OldSigIntAction, NULL) == -1) {
+        Printf("Failed to restore SIGINT handling\n");
+        FailedRestore = true;
+      }
+      if (sigaction(SIGQUIT, &OldSigQuitAction, NULL) == -1) {
+        Printf("Failed to restore SIGQUIT handling\n");
+        FailedRestore = true;
+      }
+      if (sigprocmask(SIG_BLOCK, &OldBlockedSignalsSet, NULL) == -1) {
+        Printf("Failed to unblock SIGCHLD\n");
+        FailedRestore = true;
+      }
+      if (FailedRestore)
+        ProcessStatus = -1;
+    }
+  }
+  return ProcessStatus;
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_APPLE

test/fuzz_test/Fuzzer/FuzzerUtilLinux.cpp

@@ -0,0 +1,24 @@
+//===- FuzzerUtilLinux.cpp - Misc utils for Linux. ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Misc utils for Linux.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_LINUX
+
+#include <stdlib.h>
+
+namespace fuzzer {
+
+int ExecuteCommand(const std::string &Command) {
+  return system(Command.c_str());
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_LINUX

test/fuzz_test/Fuzzer/FuzzerUtilPosix.cpp

@@ -0,0 +1,117 @@
+//===- FuzzerUtilPosix.cpp - Misc utils for Posix. ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Misc utils implementation using Posix API.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_POSIX
+#include "FuzzerIO.h"
+#include "FuzzerInternal.h"
+#include <cassert>
+#include <chrono>
+#include <cstring>
+#include <errno.h>
+#include <iomanip>
+#include <signal.h>
+#include <sstream>
+#include <stdio.h>
+#include <sys/resource.h>
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <thread>
+#include <unistd.h>
+
+namespace fuzzer {
+
+static void AlarmHandler(int, siginfo_t *, void *) {
+  Fuzzer::StaticAlarmCallback();
+}
+
+static void CrashHandler(int, siginfo_t *, void *) {
+  Fuzzer::StaticCrashSignalCallback();
+}
+
+static void InterruptHandler(int, siginfo_t *, void *) {
+  Fuzzer::StaticInterruptCallback();
+}
+
+static void SetSigaction(int signum,
+                         void (*callback)(int, siginfo_t *, void *)) {
+  struct sigaction sigact;
+  memset(&sigact, 0, sizeof(sigact));
+  sigact.sa_sigaction = callback;
+  if (sigaction(signum, &sigact, 0)) {
+    Printf("libFuzzer: sigaction failed with %d\n", errno);
+    exit(1);
+  }
+}
+
+void SetTimer(int Seconds) {
+  struct itimerval T {
+    {Seconds, 0}, { Seconds, 0 }
+  };
+  if (setitimer(ITIMER_REAL, &T, nullptr)) {
+    Printf("libFuzzer: setitimer failed with %d\n", errno);
+    exit(1);
+  }
+  SetSigaction(SIGALRM, AlarmHandler);
+}
+
+void SetSignalHandler(const FuzzingOptions& Options) {
+  if (Options.UnitTimeoutSec > 0)
+    SetTimer(Options.UnitTimeoutSec / 2 + 1);
+  if (Options.HandleInt)
+    SetSigaction(SIGINT, InterruptHandler);
+  if (Options.HandleTerm)
+    SetSigaction(SIGTERM, InterruptHandler);
+  if (Options.HandleSegv)
+    SetSigaction(SIGSEGV, CrashHandler);
+  if (Options.HandleBus)
+    SetSigaction(SIGBUS, CrashHandler);
+  if (Options.HandleAbrt)
+    SetSigaction(SIGABRT, CrashHandler);
+  if (Options.HandleIll)
+    SetSigaction(SIGILL, CrashHandler);
+  if (Options.HandleFpe)
+    SetSigaction(SIGFPE, CrashHandler);
+}
+
+void SleepSeconds(int Seconds) {
+  sleep(Seconds); // Use C API to avoid coverage from instrumented libc++.
+}
+
+unsigned long GetPid() { return (unsigned long)getpid(); }
+
+size_t GetPeakRSSMb() {
+  struct rusage usage;
+  if (getrusage(RUSAGE_SELF, &usage))
+    return 0;
+  if (LIBFUZZER_LINUX) {
+    // ru_maxrss is in KiB
+    return usage.ru_maxrss >> 10;
+  } else if (LIBFUZZER_APPLE) {
+    // ru_maxrss is in bytes
+    return usage.ru_maxrss >> 20;
+  }
+  assert(0 && "GetPeakRSSMb() is not implemented for your platform");
+  return 0;
+}
+
+FILE *OpenProcessPipe(const char *Command, const char *Mode) {
+  return popen(Command, Mode);
+}
+
+const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
+                         size_t PattLen) {
+  return memmem(Data, DataLen, Patt, PattLen);
+}
+
+}  // namespace fuzzer
+
+#endif // LIBFUZZER_POSIX

test/fuzz_test/Fuzzer/FuzzerUtilWindows.cpp

@@ -0,0 +1,182 @@
+//===- FuzzerUtilWindows.cpp - Misc utils for Windows. --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Misc utils implementation for Windows.
+//===----------------------------------------------------------------------===//
+#include "FuzzerDefs.h"
+#if LIBFUZZER_WINDOWS
+#include "FuzzerIO.h"
+#include "FuzzerInternal.h"
+#include <cassert>
+#include <chrono>
+#include <cstring>
+#include <errno.h>
+#include <iomanip>
+#include <signal.h>
+#include <sstream>
+#include <stdio.h>
+#include <sys/types.h>
+#include <windows.h>
+#include <Psapi.h>
+
+namespace fuzzer {
+
+static const FuzzingOptions* HandlerOpt = nullptr;
+
+LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo) {
+  switch (ExceptionInfo->ExceptionRecord->ExceptionCode) {
+    case EXCEPTION_ACCESS_VIOLATION:
+    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+    case EXCEPTION_STACK_OVERFLOW:
+      if (HandlerOpt->HandleSegv)
+        Fuzzer::StaticCrashSignalCallback();
+      break;
+    case EXCEPTION_DATATYPE_MISALIGNMENT:
+    case EXCEPTION_IN_PAGE_ERROR:
+      if (HandlerOpt->HandleBus)
+        Fuzzer::StaticCrashSignalCallback();
+      break;
+    case EXCEPTION_ILLEGAL_INSTRUCTION:
+    case EXCEPTION_PRIV_INSTRUCTION:
+      if (HandlerOpt->HandleIll)
+        Fuzzer::StaticCrashSignalCallback();
+      break;
+    case EXCEPTION_FLT_DENORMAL_OPERAND:
+    case EXCEPTION_FLT_DIVIDE_BY_ZERO:
+    case EXCEPTION_FLT_INEXACT_RESULT:
+    case EXCEPTION_FLT_INVALID_OPERATION:
+    case EXCEPTION_FLT_OVERFLOW:
+    case EXCEPTION_FLT_STACK_CHECK:
+    case EXCEPTION_FLT_UNDERFLOW:
+    case EXCEPTION_INT_DIVIDE_BY_ZERO:
+    case EXCEPTION_INT_OVERFLOW:
+      if (HandlerOpt->HandleFpe)
+        Fuzzer::StaticCrashSignalCallback();
+      break;
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+BOOL WINAPI CtrlHandler(DWORD dwCtrlType) {
+  switch (dwCtrlType) {
+    case CTRL_C_EVENT:
+      if (HandlerOpt->HandleInt)
+        Fuzzer::StaticInterruptCallback();
+      return TRUE;
+    case CTRL_BREAK_EVENT:
+      if (HandlerOpt->HandleTerm)
+        Fuzzer::StaticInterruptCallback();
+      return TRUE;
+  }
+  return FALSE;
+}
+
+void CALLBACK AlarmHandler(PVOID, BOOLEAN) {
+  Fuzzer::StaticAlarmCallback();
+}
+
+class TimerQ {
+  HANDLE TimerQueue;
+ public:
+  TimerQ() : TimerQueue(NULL) {};
+  ~TimerQ() {
+    if (TimerQueue)
+      DeleteTimerQueueEx(TimerQueue, NULL);
+  };
+  void SetTimer(int Seconds) {
+    if (!TimerQueue) {
+      TimerQueue = CreateTimerQueue();
+      if (!TimerQueue) {
+        Printf("libFuzzer: CreateTimerQueue failed.\n");
+        exit(1);
+      }
+    }
+    HANDLE Timer;
+    if (!CreateTimerQueueTimer(&Timer, TimerQueue, AlarmHandler, NULL,
+        Seconds*1000, Seconds*1000, 0)) {
+      Printf("libFuzzer: CreateTimerQueueTimer failed.\n");
+      exit(1);
+    }
+  };
+};
+
+static TimerQ Timer;
+
+static void CrashHandler(int) { Fuzzer::StaticCrashSignalCallback(); }
+
+void SetSignalHandler(const FuzzingOptions& Options) {
+  HandlerOpt = &Options;
+
+  if (Options.UnitTimeoutSec > 0)
+    Timer.SetTimer(Options.UnitTimeoutSec / 2 + 1);
+
+  if (Options.HandleInt || Options.HandleTerm)
+    if (!SetConsoleCtrlHandler(CtrlHandler, TRUE)) {
+      DWORD LastError = GetLastError();
+      Printf("libFuzzer: SetConsoleCtrlHandler failed (Error code: %lu).\n",
+        LastError);
+      exit(1);
+    }
+
+  if (Options.HandleSegv || Options.HandleBus || Options.HandleIll ||
+      Options.HandleFpe)
+    if (!AddVectoredExceptionHandler(1, ExceptionHandler)) {
+      Printf("libFuzzer: AddVectoredExceptionHandler failed.\n");
+      exit(1);
+    }
+
+  if (Options.HandleAbrt)
+    if (SIG_ERR == signal(SIGABRT, CrashHandler)) {
+      Printf("libFuzzer: signal failed with %d\n", errno);
+      exit(1);
+    }
+}
+
+void SleepSeconds(int Seconds) { Sleep(Seconds * 1000); }
+
+unsigned long GetPid() { return GetCurrentProcessId(); }
+
+size_t GetPeakRSSMb() {
+  PROCESS_MEMORY_COUNTERS info;
+  if (!GetProcessMemoryInfo(GetCurrentProcess(), &info, sizeof(info)))
+    return 0;
+  return info.PeakWorkingSetSize >> 20;
+}
+
+FILE *OpenProcessPipe(const char *Command, const char *Mode) {
+  return _popen(Command, Mode);
+}
+
+int ExecuteCommand(const std::string &Command) {
+  return system(Command.c_str());
+}
+
+const void *SearchMemory(const void *Data, size_t DataLen, const void *Patt,
+                         size_t PattLen) {
+  // TODO: make this implementation more efficient.
+  const char *Cdata = (const char *)Data;
+  const char *Cpatt = (const char *)Patt;
+
+  if (!Data || !Patt || DataLen == 0 || PattLen == 0 || DataLen < PattLen)
+    return NULL;
+
+  if (PattLen == 1)
+    return memchr(Data, *Cpatt, DataLen);
+
+  const char *End = Cdata + DataLen - PattLen + 1;
+
+  for (const char *It = Cdata; It < End; ++It)
+    if (It[0] == Cpatt[0] && memcmp(It, Cpatt, PattLen) == 0)
+      return It;
+
+  return NULL;
+}
+
+} // namespace fuzzer
+
+#endif // LIBFUZZER_WINDOWS

test/fuzz_test/Fuzzer/FuzzerValueBitMap.h

@@ -0,0 +1,87 @@
+//===- FuzzerValueBitMap.h - INTERNAL - Bit map -----------------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// ValueBitMap.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_FUZZER_VALUE_BIT_MAP_H
+#define LLVM_FUZZER_VALUE_BIT_MAP_H
+
+#include "FuzzerDefs.h"
+
+namespace fuzzer {
+
+// A bit map containing kMapSizeInWords bits.
+struct ValueBitMap {
+  static const size_t kMapSizeInBits = 65371;        // Prime.
+  static const size_t kMapSizeInBitsAligned = 65536; // 2^16
+  static const size_t kBitsInWord = (sizeof(uintptr_t) * 8);
+  static const size_t kMapSizeInWords = kMapSizeInBitsAligned / kBitsInWord;
+ public:
+  static const size_t kNumberOfItems = kMapSizeInBits;
+  // Clears all bits.
+  void Reset() { memset(Map, 0, sizeof(Map)); }
+
+  // Computes a hash function of Value and sets the corresponding bit.
+  // Returns true if the bit was changed from 0 to 1.
+  inline bool AddValue(uintptr_t Value) {
+    uintptr_t Idx = Value < kMapSizeInBits ? Value : Value % kMapSizeInBits;
+    uintptr_t WordIdx = Idx / kBitsInWord;
+    uintptr_t BitIdx = Idx % kBitsInWord;
+    uintptr_t Old = Map[WordIdx];
+    uintptr_t New = Old | (1UL << BitIdx);
+    Map[WordIdx] = New;
+    return New != Old;
+  }
+
+  inline bool Get(uintptr_t Idx) {
+    assert(Idx < kMapSizeInBits);
+    uintptr_t WordIdx = Idx / kBitsInWord;
+    uintptr_t BitIdx = Idx % kBitsInWord;
+    return Map[WordIdx] & (1UL << BitIdx);
+  }
+
+  size_t GetNumBitsSinceLastMerge() const { return NumBits; }
+
+  // Merges 'Other' into 'this', clears 'Other', updates NumBits,
+  // returns true if new bits were added.
+  ATTRIBUTE_TARGET_POPCNT
+  bool MergeFrom(ValueBitMap &Other) {
+    uintptr_t Res = 0;
+    size_t OldNumBits = NumBits;
+    for (size_t i = 0; i < kMapSizeInWords; i++) {
+      auto O = Other.Map[i];
+      auto M = Map[i];
+      if (O) {
+        Map[i] = (M |= O);
+        Other.Map[i] = 0;
+      }
+      if (M)
+        Res += __builtin_popcountl(M);
+    }
+    NumBits = Res;
+    return OldNumBits < NumBits;
+  }
+
+  template <class Callback>
+  void ForEach(Callback CB) {
+    for (size_t i = 0; i < kMapSizeInWords; i++)
+      if (uintptr_t M = Map[i])
+        for (size_t j = 0; j < sizeof(M) * 8; j++)
+          if (M & ((uintptr_t)1 << j))
+            CB(i * sizeof(M) * 8 + j);
+  }
+
+ private:
+  size_t NumBits = 0;
+  uintptr_t Map[kMapSizeInWords] __attribute__((aligned(512)));
+};
+
+}  // namespace fuzzer
+
+#endif  // LLVM_FUZZER_VALUE_BIT_MAP_H

test/fuzz_test/Fuzzer/README.txt

@@ -0,0 +1,2 @@
+Move to http://llvm.org/docs/LibFuzzer.html
+

test/fuzz_test/Fuzzer/afl/afl_driver.cpp

@@ -0,0 +1,295 @@
+//===- afl_driver.cpp - a glue between AFL and libFuzzer --------*- C++ -* ===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//===----------------------------------------------------------------------===//
+
+/* This file allows to fuzz libFuzzer-style target functions
+ (LLVMFuzzerTestOneInput) with AFL using AFL's persistent (in-process) mode.
+
+Usage:
+################################################################################
+cat << EOF > test_fuzzer.cc
+#include <stdint.h>
+#include <stddef.h>
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+  if (size > 0 && data[0] == 'H')
+    if (size > 1 && data[1] == 'I')
+       if (size > 2 && data[2] == '!')
+       __builtin_trap();
+  return 0;
+}
+EOF
+# Build your target with -fsanitize-coverage=trace-pc using fresh clang.
+clang -g -fsanitize-coverage=trace-pc test_fuzzer.cc -c
+# Build afl-llvm-rt.o.c from the AFL distribution.
+clang -c -w $AFL_HOME/llvm_mode/afl-llvm-rt.o.c
+# Build this file, link it with afl-llvm-rt.o.o and the target code.
+clang++ afl_driver.cpp test_fuzzer.o afl-llvm-rt.o.o
+# Run AFL:
+rm -rf IN OUT; mkdir IN OUT; echo z > IN/z;
+$AFL_HOME/afl-fuzz -i IN -o OUT ./a.out
+################################################################################
+Environment Variables:
+There are a few environment variables that can be set to use features that
+afl-fuzz doesn't have.
+
+AFL_DRIVER_STDERR_DUPLICATE_FILENAME: Setting this *appends* stderr to the file
+specified. If the file does not exist, it is created. This is useful for getting
+stack traces (when using ASAN for example) or original error messages on hard to
+reproduce bugs.
+
+AFL_DRIVER_EXTRA_STATS_FILENAME: Setting this causes afl_driver to write extra
+statistics to the file specified. Currently these are peak_rss_mb
+(the peak amount of virtual memory used in MB) and slowest_unit_time_secs. If
+the file does not exist it is created. If the file does exist then
+afl_driver assumes it was restarted by afl-fuzz and will try to read old
+statistics from the file. If that fails then the process will quit.
+
+*/
+#include <assert.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+// Platform detection. Copied from FuzzerInternal.h
+#ifdef __linux__
+#define LIBFUZZER_LINUX 1
+#define LIBFUZZER_APPLE 0
+#elif __APPLE__
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_APPLE 1
+#else
+#error "Support for your platform has not been implemented"
+#endif
+
+// Used to avoid repeating error checking boilerplate. If cond is false, a
+// fatal error has occured in the program. In this event print error_message
+// to stderr and abort(). Otherwise do nothing. Note that setting
+// AFL_DRIVER_STDERR_DUPLICATE_FILENAME may cause error_message to be appended
+// to the file as well, if the error occurs after the duplication is performed.
+#define CHECK_ERROR(cond, error_message)                                       \
+  if (!(cond)) {                                                               \
+    fprintf(stderr, (error_message));                                          \
+    abort();                                                                   \
+  }
+
+// libFuzzer interface is thin, so we don't include any libFuzzer headers.
+extern "C" {
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size);
+__attribute__((weak)) int LLVMFuzzerInitialize(int *argc, char ***argv);
+}
+
+// Notify AFL about persistent mode.
+static volatile char AFL_PERSISTENT[] = "##SIG_AFL_PERSISTENT##";
+extern "C" int __afl_persistent_loop(unsigned int);
+static volatile char suppress_warning2 = AFL_PERSISTENT[0];
+
+// Notify AFL about deferred forkserver.
+static volatile char AFL_DEFER_FORKSVR[] = "##SIG_AFL_DEFER_FORKSRV##";
+extern "C" void  __afl_manual_init();
+static volatile char suppress_warning1 = AFL_DEFER_FORKSVR[0];
+
+// Input buffer.
+static const size_t kMaxAflInputSize = 1 << 20;
+static uint8_t AflInputBuf[kMaxAflInputSize];
+
+// Variables we need for writing to the extra stats file.
+static FILE *extra_stats_file = NULL;
+static uint32_t previous_peak_rss = 0;
+static time_t slowest_unit_time_secs = 0;
+static const int kNumExtraStats = 2;
+static const char *kExtraStatsFormatString = "peak_rss_mb            : %u\n"
+                                             "slowest_unit_time_sec  : %u\n";
+
+// Copied from FuzzerUtil.cpp.
+size_t GetPeakRSSMb() {
+  struct rusage usage;
+  if (getrusage(RUSAGE_SELF, &usage))
+    return 0;
+  if (LIBFUZZER_LINUX) {
+    // ru_maxrss is in KiB
+    return usage.ru_maxrss >> 10;
+  } else if (LIBFUZZER_APPLE) {
+    // ru_maxrss is in bytes
+    return usage.ru_maxrss >> 20;
+  }
+  assert(0 && "GetPeakRSSMb() is not implemented for your platform");
+  return 0;
+}
+
+// Based on SetSigaction in FuzzerUtil.cpp
+static void SetSigaction(int signum,
+                         void (*callback)(int, siginfo_t *, void *)) {
+  struct sigaction sigact;
+  memset(&sigact, 0, sizeof(sigact));
+  sigact.sa_sigaction = callback;
+  if (sigaction(signum, &sigact, 0)) {
+    fprintf(stderr, "libFuzzer: sigaction failed with %d\n", errno);
+    exit(1);
+  }
+}
+
+// Write extra stats to the file specified by the user. If none is specified
+// this function will never be called.
+static void write_extra_stats() {
+  uint32_t peak_rss = GetPeakRSSMb();
+
+  if (peak_rss < previous_peak_rss)
+    peak_rss = previous_peak_rss;
+
+  int chars_printed = fprintf(extra_stats_file, kExtraStatsFormatString,
+                              peak_rss, slowest_unit_time_secs);
+
+  CHECK_ERROR(chars_printed != 0, "Failed to write extra_stats_file");
+
+  CHECK_ERROR(fclose(extra_stats_file) == 0,
+              "Failed to close extra_stats_file");
+}
+
+// Call write_extra_stats before we exit.
+static void crash_handler(int, siginfo_t *, void *) {
+  // Make sure we don't try calling write_extra_stats again if we crashed while
+  // trying to call it.
+  static bool first_crash = true;
+  CHECK_ERROR(first_crash,
+              "Crashed in crash signal handler. This is a bug in the fuzzer.");
+
+  first_crash = false;
+  write_extra_stats();
+}
+
+// If the user has specified an extra_stats_file through the environment
+// variable AFL_DRIVER_EXTRA_STATS_FILENAME, then perform necessary set up
+// to write stats to it on exit. If no file is specified, do nothing. Otherwise
+// install signal and exit handlers to write to the file when the process exits.
+// Then if the file doesn't exist create it and set extra stats to 0. But if it
+// does exist then read the initial values of the extra stats from the file
+// and check that the file is writable.
+static void maybe_initialize_extra_stats() {
+  // If AFL_DRIVER_EXTRA_STATS_FILENAME isn't set then we have nothing to do.
+  char *extra_stats_filename = getenv("AFL_DRIVER_EXTRA_STATS_FILENAME");
+  if (!extra_stats_filename)
+    return;
+
+  // Open the file and find the previous peak_rss_mb value.
+  // This is necessary because the fuzzing process is restarted after N
+  // iterations are completed. So we may need to get this value from a previous
+  // process to be accurate.
+  extra_stats_file = fopen(extra_stats_filename, "r");
+
+  // If extra_stats_file already exists: read old stats from it.
+  if (extra_stats_file) {
+    int matches = fscanf(extra_stats_file, kExtraStatsFormatString,
+                         &previous_peak_rss, &slowest_unit_time_secs);
+
+    // Make sure we have read a real extra stats file and that we have used it
+    // to set slowest_unit_time_secs and previous_peak_rss.
+    CHECK_ERROR(matches == kNumExtraStats, "Extra stats file is corrupt");
+
+    CHECK_ERROR(fclose(extra_stats_file) == 0, "Failed to close file");
+
+    // Now open the file for writing.
+    extra_stats_file = fopen(extra_stats_filename, "w");
+    CHECK_ERROR(extra_stats_file,
+                "Failed to open extra stats file for writing");
+  } else {
+    // Looks like this is the first time in a fuzzing job this is being called.
+    extra_stats_file = fopen(extra_stats_filename, "w+");
+    CHECK_ERROR(extra_stats_file, "failed to create extra stats file");
+  }
+
+  // Make sure that crash_handler gets called on any kind of fatal error.
+  int crash_signals[] = {SIGSEGV, SIGBUS, SIGABRT, SIGILL, SIGFPE,  SIGINT,
+                         SIGTERM};
+
+  const size_t num_signals = sizeof(crash_signals) / sizeof(crash_signals[0]);
+
+  for (size_t idx = 0; idx < num_signals; idx++)
+    SetSigaction(crash_signals[idx], crash_handler);
+
+  // Make sure it gets called on other kinds of exits.
+  atexit(write_extra_stats);
+}
+
+// If the user asks us to duplicate stderr, then do it.
+static void maybe_duplicate_stderr() {
+  char* stderr_duplicate_filename =
+      getenv("AFL_DRIVER_STDERR_DUPLICATE_FILENAME");
+
+  if (!stderr_duplicate_filename)
+    return;
+
+  FILE* stderr_duplicate_stream =
+      freopen(stderr_duplicate_filename, "a+", stderr);
+
+  if (!stderr_duplicate_stream) {
+    fprintf(
+        stderr,
+        "Failed to duplicate stderr to AFL_DRIVER_STDERR_DUPLICATE_FILENAME");
+    abort();
+  }
+}
+
+int main(int argc, char **argv) {
+  fprintf(stderr, "======================= INFO =========================\n"
+                  "This binary is built for AFL-fuzz.\n"
+                  "To run the target function on a single input execute this:\n"
+                  "  %s < INPUT_FILE\n"
+                  "To run the fuzzing execute this:\n"
+                  "  afl-fuzz [afl-flags] %s [N] "
+                  "-- run N fuzzing iterations before "
+                  "re-spawning the process (default: 1000)\n"
+                  "======================================================\n",
+          argv[0], argv[0]);
+  if (LLVMFuzzerInitialize)
+    LLVMFuzzerInitialize(&argc, &argv);
+  // Do any other expensive one-time initialization here.
+
+  maybe_duplicate_stderr();
+  maybe_initialize_extra_stats();
+
+  __afl_manual_init();
+
+  int N = 1000;
+  if (argc >= 2)
+    N = atoi(argv[1]);
+  assert(N > 0);
+  time_t unit_time_secs;
+  int num_runs = 0;
+  while (__afl_persistent_loop(N)) {
+    ssize_t n_read = read(0, AflInputBuf, kMaxAflInputSize);
+    if (n_read > 0) {
+      // Copy AflInputBuf into a separate buffer to let asan find buffer
+      // overflows. Don't use unique_ptr/etc to avoid extra dependencies.
+      uint8_t *copy = new uint8_t[n_read];
+      memcpy(copy, AflInputBuf, n_read);
+
+      struct timeval unit_start_time;
+      CHECK_ERROR(gettimeofday(&unit_start_time, NULL) == 0,
+                  "Calling gettimeofday failed");
+
+      num_runs++;
+      LLVMFuzzerTestOneInput(copy, n_read);
+
+      struct timeval unit_stop_time;
+      CHECK_ERROR(gettimeofday(&unit_stop_time, NULL) == 0,
+                  "Calling gettimeofday failed");
+
+      // Update slowest_unit_time_secs if we see a new max.
+      unit_time_secs = unit_stop_time.tv_sec - unit_start_time.tv_sec;
+      if (slowest_unit_time_secs < unit_time_secs)
+        slowest_unit_time_secs = unit_time_secs;
+
+      delete[] copy;
+    }
+  }
+  fprintf(stderr, "%s: successfully executed %d input(s)\n", argv[0], num_runs);
+}

test/fuzz_test/Fuzzer/build.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+LIBFUZZER_SRC_DIR=$(dirname $0)
+for f in $LIBFUZZER_SRC_DIR/*.cpp; do
+  clang -g -O2 -fno-omit-frame-pointer -std=c++11 $f -c &
+done
+wait
+rm -f libFuzzer.a
+ar ru libFuzzer.a Fuzzer*.o
+rm -f Fuzzer*.o
+

test/fuzz_test/Fuzzer/cxx.dict

@@ -0,0 +1,122 @@
+"++"
+"--"
+"<<"
+">>"
+"+="
+"-="
+"*="
+"/="
+">>="
+"<<="
+"&="
+"|="
+"^="
+"%="
+"!="
+"&&"
+"||"
+"=="
+">="
+"<="
+"->"
+"alignas"
+"alignof"
+"and"
+"and_eq"
+"asm"
+"auto"
+"bitand"
+"bitor"
+"bool"
+"break"
+"case"
+"catch"
+"char"
+"char16_t"
+"char32_t"
+"class"
+"compl"
+"concept"
+"const"
+"constexpr"
+"const_cast"
+"continue"
+"decltype"
+"default"
+"delete"
+"do"
+"double"
+"dynamic_cast"
+"else"
+"enum"
+"explicit"
+"export"
+"extern"
+"false"
+"float"
+"for"
+"friend"
+"goto"
+"if"
+"inline"
+"int"
+"long"
+"mutable"
+"namespace"
+"new"
+"noexcept"
+"not"
+"not_eq"
+"nullptr"
+"operator"
+"or"
+"or_eq"
+"private"
+"protected"
+"public"
+"register"
+"reinterpret_cast"
+"requires"
+"return"
+"short"
+"signed"
+"sizeof"
+"static"
+"static_assert"
+"static_cast"
+"struct"
+"switch"
+"template"
+"this"
+"thread_local"
+"throw"
+"true"
+"try"
+"typedef"
+"typeid"
+"typename"
+"union"
+"unsigned"
+"using"
+"virtual"
+"void"
+"volatile"
+"wchar_t"
+"while"
+"xor"
+"xor_eq"
+"if"
+"elif"
+"else"
+"endif"
+"defined"
+"ifdef"
+"ifndef"
+"define"
+"undef"
+"include"
+"line"
+"error"
+"pragma"
+"override"
+"final"

test/fuzz_test/Fuzzer/standalone/StandaloneFuzzTargetMain.c

@@ -0,0 +1,41 @@
+/*===- StandaloneFuzzTargetMain.c - standalone main() for fuzz targets. ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// This main() function can be linked to a fuzz target (i.e. a library
+// that exports LLVMFuzzerTestOneInput() and possibly LLVMFuzzerInitialize())
+// instead of libFuzzer. This main() function will not perform any fuzzing
+// but will simply feed all input files one by one to the fuzz target.
+//
+// Use this file to provide reproducers for bugs when linking against libFuzzer
+// or other fuzzing engine is undesirable.
+//===----------------------------------------------------------------------===*/
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int LLVMFuzzerTestOneInput(const unsigned char *data, size_t size);
+__attribute__((weak)) extern int LLVMFuzzerInitialize(int *argc, char ***argv);
+int main(int argc, char **argv) {
+  fprintf(stderr, "StandaloneFuzzTargetMain: running %d inputs\n", argc - 1);
+  if (LLVMFuzzerInitialize)
+    LLVMFuzzerInitialize(&argc, &argv);
+  for (int i = 1; i < argc; i++) {
+    fprintf(stderr, "Running: %s\n", argv[i]);
+    FILE *f = fopen(argv[i], "r");
+    assert(f);
+    fseek(f, 0, SEEK_END);
+    size_t len = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    unsigned char *buf = (unsigned char*)malloc(len);
+    size_t n_read = fread(buf, 1, len, f);
+    assert(n_read == len);
+    LLVMFuzzerTestOneInput(buf, len);
+    free(buf);
+    fprintf(stderr, "Done:    %s: (%zd bytes)\n", argv[i], n_read);
+  }
+}

test/fuzz_test/Fuzzer/test/AFLDriverTest.cpp

@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Contains dummy functions used to avoid dependency on AFL.
+#include <stdint.h>
+#include <stdlib.h>
+
+extern "C" void __afl_manual_init() {}
+
+extern "C" int __afl_persistent_loop(unsigned int) {
+  return 0;
+}
+
+// This declaration exists to prevent the Darwin linker
+// from complaining about this being a missing weak symbol.
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv) {
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  return 0;
+}

test/fuzz_test/Fuzzer/test/AbsNegAndConstant64Test.cpp

@@ -0,0 +1,23 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// abs(x) < 0 and y == Const puzzle, 64-bit variant.
+#include <cstring>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstdio>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 16) return 0;
+  int64_t x;
+  uint64_t y;
+  memcpy(&x, Data, sizeof(x));
+  memcpy(&y, Data + sizeof(x), sizeof(y));
+  if (labs(x) < 0 && y == 0xbaddcafedeadbeefUL) {
+    printf("BINGO; Found the target, exiting; x = 0x%lx y 0x%lx\n", x, y);
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/AbsNegAndConstantTest.cpp

@@ -0,0 +1,23 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// abs(x) < 0 and y == Const puzzle.
+#include <cstring>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstdio>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 8) return 0;
+  int x;
+  unsigned y;
+  memcpy(&x, Data, sizeof(x));
+  memcpy(&y, Data + sizeof(x), sizeof(y));
+  if (abs(x) < 0 && y == 0xbaddcafe) {
+    printf("BINGO; Found the target, exiting; x = 0x%x y 0x%x\n", x, y);
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/AccumulateAllocationsTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test with a more mallocs than frees, but no leak.
+#include <cstdint>
+#include <cstddef>
+
+const int kAllocatedPointersSize = 10000;
+int NumAllocatedPointers = 0;
+int *AllocatedPointers[kAllocatedPointersSize];
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (NumAllocatedPointers < kAllocatedPointersSize)
+    AllocatedPointers[NumAllocatedPointers++] = new int;
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/BufferOverflowOnInput.cpp

@@ -0,0 +1,23 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "Hi!".
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile bool SeedLargeBuffer;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size >= 4)
+    SeedLargeBuffer = true;
+  if (Size == 3 && SeedLargeBuffer && Data[3]) {
+    std::cout << "Woops, reading Data[3] w/o crashing\n";
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/CMakeLists.txt

@@ -0,0 +1,217 @@
+# Build all these tests with -O0, otherwise optimizations may merge some
+# basic blocks and we'll fail to discover the targets.
+# We change the flags for every build type because we might be doing
+# a multi-configuration build (e.g. Xcode) where CMAKE_BUILD_TYPE doesn't
+# mean anything.
+set(variables_to_filter
+  CMAKE_CXX_FLAGS_RELEASE
+  CMAKE_CXX_FLAGS_DEBUG
+  CMAKE_CXX_FLAGS_RELWITHDEBINFO
+  CMAKE_CXX_FLAGS_MINSIZEREL
+  LIBFUZZER_FLAGS_BASE
+  )
+foreach (VARNAME ${variables_to_filter})
+  string(REPLACE " " ";" BUILD_FLAGS_AS_LIST "${${VARNAME}}")
+  set(new_flags "")
+  foreach (flag ${BUILD_FLAGS_AS_LIST})
+    # NOTE: Use of XX here is to avoid a CMake warning due to CMP0054
+    if (NOT ("XX${flag}" MATCHES "XX-O[0123s]"))
+      set(new_flags "${new_flags} ${flag}")
+    else()
+      set(new_flags "${new_flags} -O0")
+    endif()
+  endforeach()
+  set(${VARNAME} "${new_flags}")
+endforeach()
+
+# Enable the coverage instrumentation (it is disabled for the Fuzzer lib).
+set(CMAKE_CXX_FLAGS "${LIBFUZZER_FLAGS_BASE} -fsanitize-coverage=trace-pc-guard,indirect-calls,trace-cmp,trace-div,trace-gep -g")
+
+# add_libfuzzer_test(<name>
+#   SOURCES source0.cpp [source1.cpp ...]
+#   )
+#
+#   Declares a LibFuzzer test executable with target name LLVMFuzzer-<name>.
+#
+#   One or more source files to be compiled into the binary must be declared
+#   after the SOURCES keyword.
+function(add_libfuzzer_test name)
+  set(multi_arg_options "SOURCES")
+  cmake_parse_arguments(
+    "add_libfuzzer_test" "" "" "${multi_arg_options}" ${ARGN})
+  if ("${add_libfuzzer_test_SOURCES}" STREQUAL "")
+    message(FATAL_ERROR "Source files must be specified")
+  endif()
+  add_executable(LLVMFuzzer-${name}
+    ${add_libfuzzer_test_SOURCES}
+    )
+  target_link_libraries(LLVMFuzzer-${name} LLVMFuzzer)
+  # Place binary where llvm-lit expects to find it
+  set_target_properties(LLVMFuzzer-${name}
+    PROPERTIES RUNTIME_OUTPUT_DIRECTORY
+    "${CMAKE_BINARY_DIR}/lib/Fuzzer/test"
+    )
+  set(TestBinaries ${TestBinaries} LLVMFuzzer-${name} PARENT_SCOPE)
+endfunction()
+
+# Variable to keep track of all test targets
+set(TestBinaries)
+
+###############################################################################
+# Basic tests
+###############################################################################
+
+set(Tests
+  AbsNegAndConstantTest
+  AbsNegAndConstant64Test
+  AccumulateAllocationsTest
+  BufferOverflowOnInput
+  CallerCalleeTest
+  CounterTest
+  CustomCrossOverTest
+  CustomMutatorTest
+  DivTest
+  EmptyTest
+  FourIndependentBranchesTest
+  FullCoverageSetTest
+  InitializeTest
+  MemcmpTest
+  LeakTest
+  LeakTimeoutTest
+  LoadTest
+  NullDerefTest
+  NullDerefOnEmptyTest
+  NthRunCrashTest
+  OneHugeAllocTest
+  OutOfMemoryTest
+  OutOfMemorySingleLargeMallocTest
+  RepeatedMemcmp
+  RepeatedBytesTest
+  SimpleCmpTest
+  SimpleDictionaryTest
+  SimpleHashTest
+  SimpleTest
+  SimpleThreadedTest
+  SingleMemcmpTest
+  SingleStrcmpTest
+  SingleStrncmpTest
+  SpamyTest
+  ShrinkControlFlowTest
+  ShrinkValueProfileTest
+  StrcmpTest
+  StrncmpOOBTest
+  StrncmpTest
+  StrstrTest
+  SwapCmpTest
+  SwitchTest
+  Switch2Test
+  ThreadedLeakTest
+  ThreadedTest
+  TimeoutTest
+  TimeoutEmptyTest
+  TraceMallocTest
+  )
+
+if(APPLE)
+  # LeakSanitizer is not supported on OSX right now
+  set(HAS_LSAN 0)
+  message(WARNING "LeakSanitizer is not supported on Apple platforms."
+    " Building and running LibFuzzer LeakSanitizer tests is disabled."
+    )
+else()
+  set(HAS_LSAN 1)
+endif()
+
+foreach(Test ${Tests})
+  add_libfuzzer_test(${Test} SOURCES ${Test}.cpp)
+endforeach()
+
+
+###############################################################################
+# Unit tests
+###############################################################################
+
+add_executable(LLVMFuzzer-Unittest
+  FuzzerUnittest.cpp
+  )
+
+add_executable(LLVMFuzzer-StandaloneInitializeTest
+  InitializeTest.cpp
+  ../standalone/StandaloneFuzzTargetMain.c
+  )
+
+target_link_libraries(LLVMFuzzer-Unittest
+  gtest
+  gtest_main
+  LLVMFuzzerNoMain
+  )
+
+target_include_directories(LLVMFuzzer-Unittest PRIVATE
+  "${LLVM_MAIN_SRC_DIR}/utils/unittest/googletest/include"
+  )
+
+set(TestBinaries ${TestBinaries} LLVMFuzzer-Unittest)
+set_target_properties(LLVMFuzzer-Unittest
+  PROPERTIES RUNTIME_OUTPUT_DIRECTORY
+  "${CMAKE_CURRENT_BINARY_DIR}"
+)
+
+set(TestBinaries ${TestBinaries} LLVMFuzzer-StandaloneInitializeTest)
+set_target_properties(LLVMFuzzer-StandaloneInitializeTest
+  PROPERTIES RUNTIME_OUTPUT_DIRECTORY
+  "${CMAKE_CURRENT_BINARY_DIR}"
+)
+
+###############################################################################
+# Additional tests
+###############################################################################
+
+include_directories(..)
+
+# add_subdirectory(uninstrumented)
+add_subdirectory(no-coverage)
+add_subdirectory(ubsan)
+
+add_library(LLVMFuzzer-DSO1 SHARED DSO1.cpp)
+add_library(LLVMFuzzer-DSO2 SHARED DSO2.cpp)
+
+add_executable(LLVMFuzzer-DSOTest
+  DSOTestMain.cpp
+  DSOTestExtra.cpp)
+
+target_link_libraries(LLVMFuzzer-DSOTest
+  LLVMFuzzer-DSO1
+  LLVMFuzzer-DSO2
+  LLVMFuzzer
+  )
+
+set_target_properties(LLVMFuzzer-DSOTest PROPERTIES RUNTIME_OUTPUT_DIRECTORY
+  "${CMAKE_BINARY_DIR}/lib/Fuzzer/test")
+set_target_properties(LLVMFuzzer-DSO1 PROPERTIES LIBRARY_OUTPUT_DIRECTORY
+  "${CMAKE_BINARY_DIR}/lib/Fuzzer/lib")
+set_target_properties(LLVMFuzzer-DSO2 PROPERTIES LIBRARY_OUTPUT_DIRECTORY
+  "${CMAKE_BINARY_DIR}/lib/Fuzzer/lib")
+
+set(TestBinaries ${TestBinaries} LLVMFuzzer-DSOTest)
+
+###############################################################################
+# Configure lit to run the tests
+#
+# Note this is done after declaring all tests so we can inform lit if any tests
+# need to be disabled.
+###############################################################################
+
+configure_lit_site_cfg(
+  ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.in
+  ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
+  )
+
+configure_lit_site_cfg(
+  ${CMAKE_CURRENT_SOURCE_DIR}/unit/lit.site.cfg.in
+  ${CMAKE_CURRENT_BINARY_DIR}/unit/lit.site.cfg
+  )
+
+add_lit_testsuite(check-fuzzer "Running Fuzzer tests"
+    ${CMAKE_CURRENT_BINARY_DIR}
+    DEPENDS ${TestBinaries} FileCheck not
+    )

test/fuzz_test/Fuzzer/test/CallerCalleeTest.cpp

@@ -0,0 +1,59 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer.
+// Try to find the target using the indirect caller-callee pairs.
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+
+typedef void (*F)();
+static F t[256];
+
+void f34() {
+  std::cerr << "BINGO\n";
+  exit(1);
+}
+void f23() { t[(unsigned)'d'] = f34;}
+void f12() { t[(unsigned)'c'] = f23;}
+void f01() { t[(unsigned)'b'] = f12;}
+void f00() {}
+
+static F t0[256] = {
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+  f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00, f00,
+};
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 4) return 0;
+  // Spoof the counters.
+  for (int i = 0; i < 200; i++) {
+    f23();
+    f12();
+    f01();
+  }
+  memcpy(t, t0, sizeof(t));
+  t[(unsigned)'a'] = f01;
+  t[Data[0]]();
+  t[Data[1]]();
+  t[Data[2]]();
+  t[Data[3]]();
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/CounterTest.cpp

@@ -0,0 +1,18 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for a fuzzer: must find the case where a particular basic block is
+// executed many times.
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int Num = 0;
+  for (size_t i = 0; i < Size; i++)
+    if (Data[i] == 'A' + i)
+      Num++;
+  if (Num >= 4) {
+    std::cerr <<  "BINGO!\n";
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/CustomCrossOverTest.cpp

@@ -0,0 +1,63 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a cutom mutator.
+#include <assert.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <random>
+#include <string.h>
+
+#include "FuzzerInterface.h"
+
+static const char *Separator = "-_^_-";
+static const char *Target = "012-_^_-abc";
+
+static volatile int sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  std::string Str(reinterpret_cast<const char *>(Data), Size);
+
+  // Ensure that two different elements exist in the corpus.
+  if (Size && Data[0] == '0') sink++;
+  if (Size && Data[0] == 'a') sink--;
+
+  if (Str.find(Target) != std::string::npos) {
+    std::cout << "BINGO; Found the target, exiting\n";
+    exit(1);
+  }
+  return 0;
+}
+
+extern "C" size_t LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
+                                            const uint8_t *Data2, size_t Size2,
+                                            uint8_t *Out, size_t MaxOutSize,
+                                            unsigned int Seed) {
+  static bool Printed;
+  static size_t SeparatorLen = strlen(Separator);
+
+  if (!Printed) {
+    std::cerr << "In LLVMFuzzerCustomCrossover\n";
+    Printed = true;
+  }
+
+  std::mt19937 R(Seed);
+
+  size_t Offset1 = 0;
+  size_t Len1 = R() % (Size1 - Offset1);
+  size_t Offset2 = 0;
+  size_t Len2 = R() % (Size2 - Offset2);
+  size_t Size = Len1 + Len2 + SeparatorLen;
+
+  if (Size > MaxOutSize)
+    return 0;
+
+  memcpy(Out, Data1 + Offset1, Len1);
+  memcpy(Out + Len1, Separator, SeparatorLen);
+  memcpy(Out + Len1 + SeparatorLen, Data2 + Offset2, Len2);
+
+  return Len1 + Len2 + SeparatorLen;
+}

test/fuzz_test/Fuzzer/test/CustomMutatorTest.cpp

@@ -0,0 +1,38 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a cutom mutator.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+#include "FuzzerInterface.h"
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        std::cout << "BINGO; Found the target, exiting\n";
+        exit(1);
+      }
+    }
+  }
+  return 0;
+}
+
+extern "C" size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
+                                          size_t MaxSize, unsigned int Seed) {
+  static bool Printed;
+  if (!Printed) {
+    std::cerr << "In LLVMFuzzerCustomMutator\n";
+    Printed = true;
+  }
+  return LLVMFuzzerMutate(Data, Size, MaxSize);
+}

test/fuzz_test/Fuzzer/test/DSO1.cpp

@@ -0,0 +1,12 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Source code for a simple DSO.
+
+int DSO1(int a) {
+  if (a < 123456)
+    return 0;
+  return 1;
+}
+
+void Uncovered1() { }

test/fuzz_test/Fuzzer/test/DSO2.cpp

@@ -0,0 +1,12 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Source code for a simple DSO.
+
+int DSO2(int a) {
+  if (a < 3598235)
+    return 0;
+  return 1;
+}
+
+void Uncovered2() {}

test/fuzz_test/Fuzzer/test/DSOTestExtra.cpp

@@ -0,0 +1,11 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Source code for a simple DSO.
+
+int DSOTestExtra(int a) {
+  if (a < 452345)
+    return 0;
+  return 1;
+}
+

test/fuzz_test/Fuzzer/test/DSOTestMain.cpp

@@ -0,0 +1,31 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Source code for a simple DSO.
+
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+extern int DSO1(int a);
+extern int DSO2(int a);
+extern int DSOTestExtra(int a);
+
+static volatile int *nil = 0;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int x, y, z;
+  if (Size < sizeof(int) * 3) {
+    x = y = z = 0;
+  } else {
+    memcpy(&x, Data + 0 * sizeof(int), sizeof(int));
+    memcpy(&y, Data + 1 * sizeof(int), sizeof(int));
+    memcpy(&z, Data + 2 * sizeof(int), sizeof(int));
+  }
+  int sum = DSO1(x) + DSO2(y) + (z ? DSOTestExtra(z) : 0);
+  if (sum == 3) {
+    fprintf(stderr, "BINGO %d %d %d\n", x, y, z);
+    *nil = 0;
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/DivTest.cpp

@@ -0,0 +1,20 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer: find the interesting argument for div.
+#include <assert.h>
+#include <cstdint>
+#include <cstring>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 4) return 0;
+  int a;
+  memcpy(&a, Data, 4);
+  Sink = 12345678 / (987654 - a);
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/EmptyTest.cpp

@@ -0,0 +1,11 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+// A fuzzer with empty target function.
+
+#include <cstdint>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  return 0;
+}

test/fuzz_test/Fuzzer/test/FourIndependentBranchesTest.cpp

@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "FUZZ".
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int bits = 0;
+  if (Size > 0 && Data[0] == 'F') bits |= 1;
+  if (Size > 1 && Data[1] == 'U') bits |= 2;
+  if (Size > 2 && Data[2] == 'Z') bits |= 4;
+  if (Size > 3 && Data[3] == 'Z') bits |= 8;
+  if (bits == 15) {
+    std::cerr <<  "BINGO!\n";
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/FullCoverageSetTest.cpp

@@ -0,0 +1,24 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "FUZZER".
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int bits = 0;
+  if (Size > 0 && Data[0] == 'F') bits |= 1;
+  if (Size > 1 && Data[1] == 'U') bits |= 2;
+  if (Size > 2 && Data[2] == 'Z') bits |= 4;
+  if (Size > 3 && Data[3] == 'Z') bits |= 8;
+  if (Size > 4 && Data[4] == 'E') bits |= 16;
+  if (Size > 5 && Data[5] == 'R') bits |= 32;
+  if (bits == 63) {
+    std::cerr <<  "BINGO!\n";
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/FuzzerUnittest.cpp

@@ -0,0 +1,738 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Avoid ODR violations (LibFuzzer is built without ASan and this test is built
+// with ASan) involving C++ standard library types when using libcxx.
+#define _LIBCPP_HAS_NO_ASAN
+
+#include "FuzzerCorpus.h"
+#include "FuzzerInternal.h"
+#include "FuzzerDictionary.h"
+#include "FuzzerMerge.h"
+#include "FuzzerMutate.h"
+#include "FuzzerRandom.h"
+#include "gtest/gtest.h"
+#include <memory>
+#include <set>
+
+using namespace fuzzer;
+
+// For now, have LLVMFuzzerTestOneInput just to make it link.
+// Later we may want to make unittests that actually call LLVMFuzzerTestOneInput.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  abort();
+}
+
+TEST(Fuzzer, CrossOver) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  Unit A({0, 1, 2}), B({5, 6, 7});
+  Unit C;
+  Unit Expected[] = {
+       { 0 },
+       { 0, 1 },
+       { 0, 5 },
+       { 0, 1, 2 },
+       { 0, 1, 5 },
+       { 0, 5, 1 },
+       { 0, 5, 6 },
+       { 0, 1, 2, 5 },
+       { 0, 1, 5, 2 },
+       { 0, 1, 5, 6 },
+       { 0, 5, 1, 2 },
+       { 0, 5, 1, 6 },
+       { 0, 5, 6, 1 },
+       { 0, 5, 6, 7 },
+       { 0, 1, 2, 5, 6 },
+       { 0, 1, 5, 2, 6 },
+       { 0, 1, 5, 6, 2 },
+       { 0, 1, 5, 6, 7 },
+       { 0, 5, 1, 2, 6 },
+       { 0, 5, 1, 6, 2 },
+       { 0, 5, 1, 6, 7 },
+       { 0, 5, 6, 1, 2 },
+       { 0, 5, 6, 1, 7 },
+       { 0, 5, 6, 7, 1 },
+       { 0, 1, 2, 5, 6, 7 },
+       { 0, 1, 5, 2, 6, 7 },
+       { 0, 1, 5, 6, 2, 7 },
+       { 0, 1, 5, 6, 7, 2 },
+       { 0, 5, 1, 2, 6, 7 },
+       { 0, 5, 1, 6, 2, 7 },
+       { 0, 5, 1, 6, 7, 2 },
+       { 0, 5, 6, 1, 2, 7 },
+       { 0, 5, 6, 1, 7, 2 },
+       { 0, 5, 6, 7, 1, 2 }
+  };
+  for (size_t Len = 1; Len < 8; Len++) {
+    std::set<Unit> FoundUnits, ExpectedUnitsWitThisLength;
+    for (int Iter = 0; Iter < 3000; Iter++) {
+      C.resize(Len);
+      size_t NewSize = MD.CrossOver(A.data(), A.size(), B.data(), B.size(),
+                                    C.data(), C.size());
+      C.resize(NewSize);
+      FoundUnits.insert(C);
+    }
+    for (const Unit &U : Expected)
+      if (U.size() <= Len)
+        ExpectedUnitsWitThisLength.insert(U);
+    EXPECT_EQ(ExpectedUnitsWitThisLength, FoundUnits);
+  }
+}
+
+TEST(Fuzzer, Hash) {
+  uint8_t A[] = {'a', 'b', 'c'};
+  fuzzer::Unit U(A, A + sizeof(A));
+  EXPECT_EQ("a9993e364706816aba3e25717850c26c9cd0d89d", fuzzer::Hash(U));
+  U.push_back('d');
+  EXPECT_EQ("81fe8bfe87576c3ecb22426f8e57847382917acf", fuzzer::Hash(U));
+}
+
+typedef size_t (MutationDispatcher::*Mutator)(uint8_t *Data, size_t Size,
+                                              size_t MaxSize);
+
+void TestEraseBytes(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  uint8_t REM0[8] = {0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM1[8] = {0x00, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM2[8] = {0x00, 0x11, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM3[8] = {0x00, 0x11, 0x22, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM4[8] = {0x00, 0x11, 0x22, 0x33, 0x55, 0x66, 0x77};
+  uint8_t REM5[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x66, 0x77};
+  uint8_t REM6[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x77};
+  uint8_t REM7[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+
+  uint8_t REM8[6] = {0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM9[6] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55};
+  uint8_t REM10[6] = {0x00, 0x11, 0x22, 0x55, 0x66, 0x77};
+
+  uint8_t REM11[5] = {0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t REM12[5] = {0x00, 0x11, 0x22, 0x33, 0x44};
+  uint8_t REM13[5] = {0x00, 0x44, 0x55, 0x66, 0x77};
+
+
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    size_t NewSize = (MD.*M)(T, sizeof(T), sizeof(T));
+    if (NewSize == 7 && !memcmp(REM0, T, 7)) FoundMask |= 1 << 0;
+    if (NewSize == 7 && !memcmp(REM1, T, 7)) FoundMask |= 1 << 1;
+    if (NewSize == 7 && !memcmp(REM2, T, 7)) FoundMask |= 1 << 2;
+    if (NewSize == 7 && !memcmp(REM3, T, 7)) FoundMask |= 1 << 3;
+    if (NewSize == 7 && !memcmp(REM4, T, 7)) FoundMask |= 1 << 4;
+    if (NewSize == 7 && !memcmp(REM5, T, 7)) FoundMask |= 1 << 5;
+    if (NewSize == 7 && !memcmp(REM6, T, 7)) FoundMask |= 1 << 6;
+    if (NewSize == 7 && !memcmp(REM7, T, 7)) FoundMask |= 1 << 7;
+
+    if (NewSize == 6 && !memcmp(REM8, T, 6)) FoundMask |= 1 << 8;
+    if (NewSize == 6 && !memcmp(REM9, T, 6)) FoundMask |= 1 << 9;
+    if (NewSize == 6 && !memcmp(REM10, T, 6)) FoundMask |= 1 << 10;
+
+    if (NewSize == 5 && !memcmp(REM11, T, 5)) FoundMask |= 1 << 11;
+    if (NewSize == 5 && !memcmp(REM12, T, 5)) FoundMask |= 1 << 12;
+    if (NewSize == 5 && !memcmp(REM13, T, 5)) FoundMask |= 1 << 13;
+  }
+  EXPECT_EQ(FoundMask, (1 << 14) - 1);
+}
+
+TEST(FuzzerMutate, EraseBytes1) {
+  TestEraseBytes(&MutationDispatcher::Mutate_EraseBytes, 200);
+}
+TEST(FuzzerMutate, EraseBytes2) {
+  TestEraseBytes(&MutationDispatcher::Mutate, 2000);
+}
+
+void TestInsertByte(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t INS0[8] = {0xF1, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+  uint8_t INS1[8] = {0x00, 0xF2, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+  uint8_t INS2[8] = {0x00, 0x11, 0xF3, 0x22, 0x33, 0x44, 0x55, 0x66};
+  uint8_t INS3[8] = {0x00, 0x11, 0x22, 0xF4, 0x33, 0x44, 0x55, 0x66};
+  uint8_t INS4[8] = {0x00, 0x11, 0x22, 0x33, 0xF5, 0x44, 0x55, 0x66};
+  uint8_t INS5[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0xF6, 0x55, 0x66};
+  uint8_t INS6[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0xF7, 0x66};
+  uint8_t INS7[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0xF8};
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+    size_t NewSize = (MD.*M)(T, 7, 8);
+    if (NewSize == 8 && !memcmp(INS0, T, 8)) FoundMask |= 1 << 0;
+    if (NewSize == 8 && !memcmp(INS1, T, 8)) FoundMask |= 1 << 1;
+    if (NewSize == 8 && !memcmp(INS2, T, 8)) FoundMask |= 1 << 2;
+    if (NewSize == 8 && !memcmp(INS3, T, 8)) FoundMask |= 1 << 3;
+    if (NewSize == 8 && !memcmp(INS4, T, 8)) FoundMask |= 1 << 4;
+    if (NewSize == 8 && !memcmp(INS5, T, 8)) FoundMask |= 1 << 5;
+    if (NewSize == 8 && !memcmp(INS6, T, 8)) FoundMask |= 1 << 6;
+    if (NewSize == 8 && !memcmp(INS7, T, 8)) FoundMask |= 1 << 7;
+  }
+  EXPECT_EQ(FoundMask, 255);
+}
+
+TEST(FuzzerMutate, InsertByte1) {
+  TestInsertByte(&MutationDispatcher::Mutate_InsertByte, 1 << 15);
+}
+TEST(FuzzerMutate, InsertByte2) {
+  TestInsertByte(&MutationDispatcher::Mutate, 1 << 17);
+}
+
+void TestInsertRepeatedBytes(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t INS0[7] = {0x00, 0x11, 0x22, 0x33, 'a', 'a', 'a'};
+  uint8_t INS1[7] = {0x00, 0x11, 0x22, 'a', 'a', 'a', 0x33};
+  uint8_t INS2[7] = {0x00, 0x11, 'a', 'a', 'a', 0x22, 0x33};
+  uint8_t INS3[7] = {0x00, 'a', 'a', 'a', 0x11, 0x22, 0x33};
+  uint8_t INS4[7] = {'a', 'a', 'a', 0x00, 0x11, 0x22, 0x33};
+
+  uint8_t INS5[8] = {0x00, 0x11, 0x22, 0x33, 'b', 'b', 'b', 'b'};
+  uint8_t INS6[8] = {0x00, 0x11, 0x22, 'b', 'b', 'b', 'b', 0x33};
+  uint8_t INS7[8] = {0x00, 0x11, 'b', 'b', 'b', 'b', 0x22, 0x33};
+  uint8_t INS8[8] = {0x00, 'b', 'b', 'b', 'b', 0x11, 0x22, 0x33};
+  uint8_t INS9[8] = {'b', 'b', 'b', 'b', 0x00, 0x11, 0x22, 0x33};
+
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {0x00, 0x11, 0x22, 0x33};
+    size_t NewSize = (MD.*M)(T, 4, 8);
+    if (NewSize == 7 && !memcmp(INS0, T, 7)) FoundMask |= 1 << 0;
+    if (NewSize == 7 && !memcmp(INS1, T, 7)) FoundMask |= 1 << 1;
+    if (NewSize == 7 && !memcmp(INS2, T, 7)) FoundMask |= 1 << 2;
+    if (NewSize == 7 && !memcmp(INS3, T, 7)) FoundMask |= 1 << 3;
+    if (NewSize == 7 && !memcmp(INS4, T, 7)) FoundMask |= 1 << 4;
+
+    if (NewSize == 8 && !memcmp(INS5, T, 8)) FoundMask |= 1 << 5;
+    if (NewSize == 8 && !memcmp(INS6, T, 8)) FoundMask |= 1 << 6;
+    if (NewSize == 8 && !memcmp(INS7, T, 8)) FoundMask |= 1 << 7;
+    if (NewSize == 8 && !memcmp(INS8, T, 8)) FoundMask |= 1 << 8;
+    if (NewSize == 8 && !memcmp(INS9, T, 8)) FoundMask |= 1 << 9;
+
+  }
+  EXPECT_EQ(FoundMask, (1 << 10) - 1);
+}
+
+TEST(FuzzerMutate, InsertRepeatedBytes1) {
+  TestInsertRepeatedBytes(&MutationDispatcher::Mutate_InsertRepeatedBytes, 10000);
+}
+TEST(FuzzerMutate, InsertRepeatedBytes2) {
+  TestInsertRepeatedBytes(&MutationDispatcher::Mutate, 300000);
+}
+
+void TestChangeByte(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t CH0[8] = {0xF0, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH1[8] = {0x00, 0xF1, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH2[8] = {0x00, 0x11, 0xF2, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH3[8] = {0x00, 0x11, 0x22, 0xF3, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH4[8] = {0x00, 0x11, 0x22, 0x33, 0xF4, 0x55, 0x66, 0x77};
+  uint8_t CH5[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0xF5, 0x66, 0x77};
+  uint8_t CH6[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0xF5, 0x77};
+  uint8_t CH7[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0xF7};
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[9] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    size_t NewSize = (MD.*M)(T, 8, 9);
+    if (NewSize == 8 && !memcmp(CH0, T, 8)) FoundMask |= 1 << 0;
+    if (NewSize == 8 && !memcmp(CH1, T, 8)) FoundMask |= 1 << 1;
+    if (NewSize == 8 && !memcmp(CH2, T, 8)) FoundMask |= 1 << 2;
+    if (NewSize == 8 && !memcmp(CH3, T, 8)) FoundMask |= 1 << 3;
+    if (NewSize == 8 && !memcmp(CH4, T, 8)) FoundMask |= 1 << 4;
+    if (NewSize == 8 && !memcmp(CH5, T, 8)) FoundMask |= 1 << 5;
+    if (NewSize == 8 && !memcmp(CH6, T, 8)) FoundMask |= 1 << 6;
+    if (NewSize == 8 && !memcmp(CH7, T, 8)) FoundMask |= 1 << 7;
+  }
+  EXPECT_EQ(FoundMask, 255);
+}
+
+TEST(FuzzerMutate, ChangeByte1) {
+  TestChangeByte(&MutationDispatcher::Mutate_ChangeByte, 1 << 15);
+}
+TEST(FuzzerMutate, ChangeByte2) {
+  TestChangeByte(&MutationDispatcher::Mutate, 1 << 17);
+}
+
+void TestChangeBit(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t CH0[8] = {0x01, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH1[8] = {0x00, 0x13, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH2[8] = {0x00, 0x11, 0x02, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH3[8] = {0x00, 0x11, 0x22, 0x37, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH4[8] = {0x00, 0x11, 0x22, 0x33, 0x54, 0x55, 0x66, 0x77};
+  uint8_t CH5[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x54, 0x66, 0x77};
+  uint8_t CH6[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x76, 0x77};
+  uint8_t CH7[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0xF7};
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[9] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    size_t NewSize = (MD.*M)(T, 8, 9);
+    if (NewSize == 8 && !memcmp(CH0, T, 8)) FoundMask |= 1 << 0;
+    if (NewSize == 8 && !memcmp(CH1, T, 8)) FoundMask |= 1 << 1;
+    if (NewSize == 8 && !memcmp(CH2, T, 8)) FoundMask |= 1 << 2;
+    if (NewSize == 8 && !memcmp(CH3, T, 8)) FoundMask |= 1 << 3;
+    if (NewSize == 8 && !memcmp(CH4, T, 8)) FoundMask |= 1 << 4;
+    if (NewSize == 8 && !memcmp(CH5, T, 8)) FoundMask |= 1 << 5;
+    if (NewSize == 8 && !memcmp(CH6, T, 8)) FoundMask |= 1 << 6;
+    if (NewSize == 8 && !memcmp(CH7, T, 8)) FoundMask |= 1 << 7;
+  }
+  EXPECT_EQ(FoundMask, 255);
+}
+
+TEST(FuzzerMutate, ChangeBit1) {
+  TestChangeBit(&MutationDispatcher::Mutate_ChangeBit, 1 << 16);
+}
+TEST(FuzzerMutate, ChangeBit2) {
+  TestChangeBit(&MutationDispatcher::Mutate, 1 << 18);
+}
+
+void TestShuffleBytes(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t CH0[7] = {0x00, 0x22, 0x11, 0x33, 0x44, 0x55, 0x66};
+  uint8_t CH1[7] = {0x11, 0x00, 0x33, 0x22, 0x44, 0x55, 0x66};
+  uint8_t CH2[7] = {0x00, 0x33, 0x11, 0x22, 0x44, 0x55, 0x66};
+  uint8_t CH3[7] = {0x00, 0x11, 0x22, 0x44, 0x55, 0x66, 0x33};
+  uint8_t CH4[7] = {0x00, 0x11, 0x22, 0x33, 0x55, 0x44, 0x66};
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[7] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+    size_t NewSize = (MD.*M)(T, 7, 7);
+    if (NewSize == 7 && !memcmp(CH0, T, 7)) FoundMask |= 1 << 0;
+    if (NewSize == 7 && !memcmp(CH1, T, 7)) FoundMask |= 1 << 1;
+    if (NewSize == 7 && !memcmp(CH2, T, 7)) FoundMask |= 1 << 2;
+    if (NewSize == 7 && !memcmp(CH3, T, 7)) FoundMask |= 1 << 3;
+    if (NewSize == 7 && !memcmp(CH4, T, 7)) FoundMask |= 1 << 4;
+  }
+  EXPECT_EQ(FoundMask, 31);
+}
+
+TEST(FuzzerMutate, ShuffleBytes1) {
+  TestShuffleBytes(&MutationDispatcher::Mutate_ShuffleBytes, 1 << 16);
+}
+TEST(FuzzerMutate, ShuffleBytes2) {
+  TestShuffleBytes(&MutationDispatcher::Mutate, 1 << 20);
+}
+
+void TestCopyPart(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  int FoundMask = 0;
+  uint8_t CH0[7] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x00, 0x11};
+  uint8_t CH1[7] = {0x55, 0x66, 0x22, 0x33, 0x44, 0x55, 0x66};
+  uint8_t CH2[7] = {0x00, 0x55, 0x66, 0x33, 0x44, 0x55, 0x66};
+  uint8_t CH3[7] = {0x00, 0x11, 0x22, 0x00, 0x11, 0x22, 0x66};
+  uint8_t CH4[7] = {0x00, 0x11, 0x11, 0x22, 0x33, 0x55, 0x66};
+
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[7] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
+    size_t NewSize = (MD.*M)(T, 7, 7);
+    if (NewSize == 7 && !memcmp(CH0, T, 7)) FoundMask |= 1 << 0;
+    if (NewSize == 7 && !memcmp(CH1, T, 7)) FoundMask |= 1 << 1;
+    if (NewSize == 7 && !memcmp(CH2, T, 7)) FoundMask |= 1 << 2;
+    if (NewSize == 7 && !memcmp(CH3, T, 7)) FoundMask |= 1 << 3;
+    if (NewSize == 7 && !memcmp(CH4, T, 7)) FoundMask |= 1 << 4;
+  }
+
+  uint8_t CH5[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x00, 0x11, 0x22};
+  uint8_t CH6[8] = {0x22, 0x33, 0x44, 0x00, 0x11, 0x22, 0x33, 0x44};
+  uint8_t CH7[8] = {0x00, 0x11, 0x22, 0x00, 0x11, 0x22, 0x33, 0x44};
+  uint8_t CH8[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x22, 0x33, 0x44};
+  uint8_t CH9[8] = {0x00, 0x11, 0x22, 0x22, 0x33, 0x44, 0x33, 0x44};
+
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    size_t NewSize = (MD.*M)(T, 5, 8);
+    if (NewSize == 8 && !memcmp(CH5, T, 8)) FoundMask |= 1 << 5;
+    if (NewSize == 8 && !memcmp(CH6, T, 8)) FoundMask |= 1 << 6;
+    if (NewSize == 8 && !memcmp(CH7, T, 8)) FoundMask |= 1 << 7;
+    if (NewSize == 8 && !memcmp(CH8, T, 8)) FoundMask |= 1 << 8;
+    if (NewSize == 8 && !memcmp(CH9, T, 8)) FoundMask |= 1 << 9;
+  }
+
+  EXPECT_EQ(FoundMask, 1023);
+}
+
+TEST(FuzzerMutate, CopyPart1) {
+  TestCopyPart(&MutationDispatcher::Mutate_CopyPart, 1 << 10);
+}
+TEST(FuzzerMutate, CopyPart2) {
+  TestCopyPart(&MutationDispatcher::Mutate, 1 << 13);
+}
+
+void TestAddWordFromDictionary(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  uint8_t Word1[4] = {0xAA, 0xBB, 0xCC, 0xDD};
+  uint8_t Word2[3] = {0xFF, 0xEE, 0xEF};
+  MD.AddWordToManualDictionary(Word(Word1, sizeof(Word1)));
+  MD.AddWordToManualDictionary(Word(Word2, sizeof(Word2)));
+  int FoundMask = 0;
+  uint8_t CH0[7] = {0x00, 0x11, 0x22, 0xAA, 0xBB, 0xCC, 0xDD};
+  uint8_t CH1[7] = {0x00, 0x11, 0xAA, 0xBB, 0xCC, 0xDD, 0x22};
+  uint8_t CH2[7] = {0x00, 0xAA, 0xBB, 0xCC, 0xDD, 0x11, 0x22};
+  uint8_t CH3[7] = {0xAA, 0xBB, 0xCC, 0xDD, 0x00, 0x11, 0x22};
+  uint8_t CH4[6] = {0x00, 0x11, 0x22, 0xFF, 0xEE, 0xEF};
+  uint8_t CH5[6] = {0x00, 0x11, 0xFF, 0xEE, 0xEF, 0x22};
+  uint8_t CH6[6] = {0x00, 0xFF, 0xEE, 0xEF, 0x11, 0x22};
+  uint8_t CH7[6] = {0xFF, 0xEE, 0xEF, 0x00, 0x11, 0x22};
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[7] = {0x00, 0x11, 0x22};
+    size_t NewSize = (MD.*M)(T, 3, 7);
+    if (NewSize == 7 && !memcmp(CH0, T, 7)) FoundMask |= 1 << 0;
+    if (NewSize == 7 && !memcmp(CH1, T, 7)) FoundMask |= 1 << 1;
+    if (NewSize == 7 && !memcmp(CH2, T, 7)) FoundMask |= 1 << 2;
+    if (NewSize == 7 && !memcmp(CH3, T, 7)) FoundMask |= 1 << 3;
+    if (NewSize == 6 && !memcmp(CH4, T, 6)) FoundMask |= 1 << 4;
+    if (NewSize == 6 && !memcmp(CH5, T, 6)) FoundMask |= 1 << 5;
+    if (NewSize == 6 && !memcmp(CH6, T, 6)) FoundMask |= 1 << 6;
+    if (NewSize == 6 && !memcmp(CH7, T, 6)) FoundMask |= 1 << 7;
+  }
+  EXPECT_EQ(FoundMask, 255);
+}
+
+TEST(FuzzerMutate, AddWordFromDictionary1) {
+  TestAddWordFromDictionary(
+      &MutationDispatcher::Mutate_AddWordFromManualDictionary, 1 << 15);
+}
+
+TEST(FuzzerMutate, AddWordFromDictionary2) {
+  TestAddWordFromDictionary(&MutationDispatcher::Mutate, 1 << 15);
+}
+
+void TestAddWordFromDictionaryWithHint(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+  uint8_t W[] = {0xAA, 0xBB, 0xCC, 0xDD, 0xFF, 0xEE, 0xEF};
+  size_t PosHint = 7777;
+  MD.AddWordToAutoDictionary({Word(W, sizeof(W)), PosHint});
+  int FoundMask = 0;
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[10000];
+    memset(T, 0, sizeof(T));
+    size_t NewSize = (MD.*M)(T, 9000, 10000);
+    if (NewSize >= PosHint + sizeof(W) &&
+        !memcmp(W, T + PosHint, sizeof(W)))
+      FoundMask = 1;
+  }
+  EXPECT_EQ(FoundMask, 1);
+}
+
+TEST(FuzzerMutate, AddWordFromDictionaryWithHint1) {
+  TestAddWordFromDictionaryWithHint(
+      &MutationDispatcher::Mutate_AddWordFromTemporaryAutoDictionary, 1 << 5);
+}
+
+TEST(FuzzerMutate, AddWordFromDictionaryWithHint2) {
+  TestAddWordFromDictionaryWithHint(&MutationDispatcher::Mutate, 1 << 10);
+}
+
+void TestChangeASCIIInteger(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+
+  uint8_t CH0[8] = {'1', '2', '3', '4', '5', '6', '7', '7'};
+  uint8_t CH1[8] = {'1', '2', '3', '4', '5', '6', '7', '9'};
+  uint8_t CH2[8] = {'2', '4', '6', '9', '1', '3', '5', '6'};
+  uint8_t CH3[8] = {'0', '6', '1', '7', '2', '8', '3', '9'};
+  int FoundMask = 0;
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {'1', '2', '3', '4', '5', '6', '7', '8'};
+    size_t NewSize = (MD.*M)(T, 8, 8);
+    /**/ if (NewSize == 8 && !memcmp(CH0, T, 8)) FoundMask |= 1 << 0;
+    else if (NewSize == 8 && !memcmp(CH1, T, 8)) FoundMask |= 1 << 1;
+    else if (NewSize == 8 && !memcmp(CH2, T, 8)) FoundMask |= 1 << 2;
+    else if (NewSize == 8 && !memcmp(CH3, T, 8)) FoundMask |= 1 << 3;
+    else if (NewSize == 8)                       FoundMask |= 1 << 4;
+  }
+  EXPECT_EQ(FoundMask, 31);
+}
+
+TEST(FuzzerMutate, ChangeASCIIInteger1) {
+  TestChangeASCIIInteger(&MutationDispatcher::Mutate_ChangeASCIIInteger,
+                         1 << 15);
+}
+
+TEST(FuzzerMutate, ChangeASCIIInteger2) {
+  TestChangeASCIIInteger(&MutationDispatcher::Mutate, 1 << 15);
+}
+
+void TestChangeBinaryInteger(Mutator M, int NumIter) {
+  std::unique_ptr<ExternalFunctions> t(new ExternalFunctions());
+  fuzzer::EF = t.get();
+  Random Rand(0);
+  MutationDispatcher MD(Rand, {});
+
+  uint8_t CH0[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x79};
+  uint8_t CH1[8] = {0x00, 0x11, 0x22, 0x31, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH2[8] = {0xff, 0x10, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH3[8] = {0x00, 0x11, 0x2a, 0x33, 0x44, 0x55, 0x66, 0x77};
+  uint8_t CH4[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x4f, 0x66, 0x77};
+  uint8_t CH5[8] = {0xff, 0xee, 0xdd, 0xcc, 0xbb, 0xaa, 0x99, 0x88};
+  uint8_t CH6[8] = {0x00, 0x11, 0x22, 0x00, 0x00, 0x00, 0x08, 0x77}; // Size
+  uint8_t CH7[8] = {0x00, 0x08, 0x00, 0x33, 0x44, 0x55, 0x66, 0x77}; // Sw(Size)
+
+  int FoundMask = 0;
+  for (int i = 0; i < NumIter; i++) {
+    uint8_t T[8] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77};
+    size_t NewSize = (MD.*M)(T, 8, 8);
+    /**/ if (NewSize == 8 && !memcmp(CH0, T, 8)) FoundMask |= 1 << 0;
+    else if (NewSize == 8 && !memcmp(CH1, T, 8)) FoundMask |= 1 << 1;
+    else if (NewSize == 8 && !memcmp(CH2, T, 8)) FoundMask |= 1 << 2;
+    else if (NewSize == 8 && !memcmp(CH3, T, 8)) FoundMask |= 1 << 3;
+    else if (NewSize == 8 && !memcmp(CH4, T, 8)) FoundMask |= 1 << 4;
+    else if (NewSize == 8 && !memcmp(CH5, T, 8)) FoundMask |= 1 << 5;
+    else if (NewSize == 8 && !memcmp(CH6, T, 8)) FoundMask |= 1 << 6;
+    else if (NewSize == 8 && !memcmp(CH7, T, 8)) FoundMask |= 1 << 7;
+  }
+  EXPECT_EQ(FoundMask, 255);
+}
+
+TEST(FuzzerMutate, ChangeBinaryInteger1) {
+  TestChangeBinaryInteger(&MutationDispatcher::Mutate_ChangeBinaryInteger,
+                         1 << 12);
+}
+
+TEST(FuzzerMutate, ChangeBinaryInteger2) {
+  TestChangeBinaryInteger(&MutationDispatcher::Mutate, 1 << 15);
+}
+
+
+TEST(FuzzerDictionary, ParseOneDictionaryEntry) {
+  Unit U;
+  EXPECT_FALSE(ParseOneDictionaryEntry("", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry(" ", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry("\t  ", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry("  \" ", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry("  zz\" ", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry("  \"zz ", &U));
+  EXPECT_FALSE(ParseOneDictionaryEntry("  \"\" ", &U));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"a\"", &U));
+  EXPECT_EQ(U, Unit({'a'}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"abc\"", &U));
+  EXPECT_EQ(U, Unit({'a', 'b', 'c'}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("abc=\"abc\"", &U));
+  EXPECT_EQ(U, Unit({'a', 'b', 'c'}));
+  EXPECT_FALSE(ParseOneDictionaryEntry("\"\\\"", &U));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"\\\\\"", &U));
+  EXPECT_EQ(U, Unit({'\\'}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"\\xAB\"", &U));
+  EXPECT_EQ(U, Unit({0xAB}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"\\xABz\\xDE\"", &U));
+  EXPECT_EQ(U, Unit({0xAB, 'z', 0xDE}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"#\"", &U));
+  EXPECT_EQ(U, Unit({'#'}));
+  EXPECT_TRUE(ParseOneDictionaryEntry("\"\\\"\"", &U));
+  EXPECT_EQ(U, Unit({'"'}));
+}
+
+TEST(FuzzerDictionary, ParseDictionaryFile) {
+  std::vector<Unit> Units;
+  EXPECT_FALSE(ParseDictionaryFile("zzz\n", &Units));
+  EXPECT_FALSE(ParseDictionaryFile("", &Units));
+  EXPECT_TRUE(ParseDictionaryFile("\n", &Units));
+  EXPECT_EQ(Units.size(), 0U);
+  EXPECT_TRUE(ParseDictionaryFile("#zzzz a b c d\n", &Units));
+  EXPECT_EQ(Units.size(), 0U);
+  EXPECT_TRUE(ParseDictionaryFile(" #zzzz\n", &Units));
+  EXPECT_EQ(Units.size(), 0U);
+  EXPECT_TRUE(ParseDictionaryFile("  #zzzz\n", &Units));
+  EXPECT_EQ(Units.size(), 0U);
+  EXPECT_TRUE(ParseDictionaryFile("  #zzzz\naaa=\"aa\"", &Units));
+  EXPECT_EQ(Units, std::vector<Unit>({Unit({'a', 'a'})}));
+  EXPECT_TRUE(
+      ParseDictionaryFile("  #zzzz\naaa=\"aa\"\n\nabc=\"abc\"", &Units));
+  EXPECT_EQ(Units,
+            std::vector<Unit>({Unit({'a', 'a'}), Unit({'a', 'b', 'c'})}));
+}
+
+TEST(FuzzerUtil, Base64) {
+  EXPECT_EQ("", Base64({}));
+  EXPECT_EQ("YQ==", Base64({'a'}));
+  EXPECT_EQ("eA==", Base64({'x'}));
+  EXPECT_EQ("YWI=", Base64({'a', 'b'}));
+  EXPECT_EQ("eHk=", Base64({'x', 'y'}));
+  EXPECT_EQ("YWJj", Base64({'a', 'b', 'c'}));
+  EXPECT_EQ("eHl6", Base64({'x', 'y', 'z'}));
+  EXPECT_EQ("YWJjeA==", Base64({'a', 'b', 'c', 'x'}));
+  EXPECT_EQ("YWJjeHk=", Base64({'a', 'b', 'c', 'x', 'y'}));
+  EXPECT_EQ("YWJjeHl6", Base64({'a', 'b', 'c', 'x', 'y', 'z'}));
+}
+
+TEST(Corpus, Distribution) {
+  Random Rand(0);
+  InputCorpus C("");
+  size_t N = 10;
+  size_t TriesPerUnit = 1<<16;
+  for (size_t i = 0; i < N; i++)
+    C.AddToCorpus(Unit{ static_cast<uint8_t>(i) }, 0);
+
+  std::vector<size_t> Hist(N);
+  for (size_t i = 0; i < N * TriesPerUnit; i++) {
+    Hist[C.ChooseUnitIdxToMutate(Rand)]++;
+  }
+  for (size_t i = 0; i < N; i++) {
+    // A weak sanity check that every unit gets invoked.
+    EXPECT_GT(Hist[i], TriesPerUnit / N / 3);
+  }
+}
+
+TEST(Merge, Bad) {
+  const char *kInvalidInputs[] = {
+    "",
+    "x",
+    "3\nx",
+    "2\n3",
+    "2\n2",
+    "2\n2\nA\n",
+    "2\n2\nA\nB\nC\n",
+    "0\n0\n",
+    "1\n1\nA\nDONE 0",
+    "1\n1\nA\nSTARTED 1",
+  };
+  Merger M;
+  for (auto S : kInvalidInputs) {
+    // fprintf(stderr, "TESTING:\n%s\n", S);
+    EXPECT_FALSE(M.Parse(S, false));
+  }
+}
+
+void EQ(const std::vector<uint32_t> &A, const std::vector<uint32_t> &B) {
+  EXPECT_EQ(A, B);
+}
+
+void EQ(const std::vector<std::string> &A, const std::vector<std::string> &B) {
+  std::set<std::string> a(A.begin(), A.end());
+  std::set<std::string> b(B.begin(), B.end());
+  EXPECT_EQ(a, b);
+}
+
+static void Merge(const std::string &Input,
+                  const std::vector<std::string> Result,
+                  size_t NumNewFeatures) {
+  Merger M;
+  std::vector<std::string> NewFiles;
+  EXPECT_TRUE(M.Parse(Input, true));
+  EXPECT_EQ(NumNewFeatures, M.Merge(&NewFiles));
+  EQ(NewFiles, Result);
+}
+
+TEST(Merge, Good) {
+  Merger M;
+
+  EXPECT_TRUE(M.Parse("1\n0\nAA\n", false));
+  EXPECT_EQ(M.Files.size(), 1U);
+  EXPECT_EQ(M.NumFilesInFirstCorpus, 0U);
+  EXPECT_EQ(M.Files[0].Name, "AA");
+  EXPECT_TRUE(M.LastFailure.empty());
+  EXPECT_EQ(M.FirstNotProcessedFile, 0U);
+
+  EXPECT_TRUE(M.Parse("2\n1\nAA\nBB\nSTARTED 0 42\n", false));
+  EXPECT_EQ(M.Files.size(), 2U);
+  EXPECT_EQ(M.NumFilesInFirstCorpus, 1U);
+  EXPECT_EQ(M.Files[0].Name, "AA");
+  EXPECT_EQ(M.Files[1].Name, "BB");
+  EXPECT_EQ(M.LastFailure, "AA");
+  EXPECT_EQ(M.FirstNotProcessedFile, 1U);
+
+  EXPECT_TRUE(M.Parse("3\n1\nAA\nBB\nC\n"
+                        "STARTED 0 1000\n"
+                        "DONE 0 1 2 3\n"
+                        "STARTED 1 1001\n"
+                        "DONE 1 4 5 6 \n"
+                        "STARTED 2 1002\n"
+                        "", true));
+  EXPECT_EQ(M.Files.size(), 3U);
+  EXPECT_EQ(M.NumFilesInFirstCorpus, 1U);
+  EXPECT_EQ(M.Files[0].Name, "AA");
+  EXPECT_EQ(M.Files[0].Size, 1000U);
+  EXPECT_EQ(M.Files[1].Name, "BB");
+  EXPECT_EQ(M.Files[1].Size, 1001U);
+  EXPECT_EQ(M.Files[2].Name, "C");
+  EXPECT_EQ(M.Files[2].Size, 1002U);
+  EXPECT_EQ(M.LastFailure, "C");
+  EXPECT_EQ(M.FirstNotProcessedFile, 3U);
+  EQ(M.Files[0].Features, {1, 2, 3});
+  EQ(M.Files[1].Features, {4, 5, 6});
+
+
+  std::vector<std::string> NewFiles;
+
+  EXPECT_TRUE(M.Parse("3\n2\nAA\nBB\nC\n"
+                        "STARTED 0 1000\nDONE 0 1 2 3\n"
+                        "STARTED 1 1001\nDONE 1 4 5 6 \n"
+                        "STARTED 2 1002\nDONE 2 6 1 3 \n"
+                        "", true));
+  EXPECT_EQ(M.Files.size(), 3U);
+  EXPECT_EQ(M.NumFilesInFirstCorpus, 2U);
+  EXPECT_TRUE(M.LastFailure.empty());
+  EXPECT_EQ(M.FirstNotProcessedFile, 3U);
+  EQ(M.Files[0].Features, {1, 2, 3});
+  EQ(M.Files[1].Features, {4, 5, 6});
+  EQ(M.Files[2].Features, {1, 3, 6});
+  EXPECT_EQ(0U, M.Merge(&NewFiles));
+  EQ(NewFiles, {});
+
+  EXPECT_TRUE(M.Parse("3\n1\nA\nB\nC\n"
+                        "STARTED 0 1000\nDONE 0 1 2 3\n"
+                        "STARTED 1 1001\nDONE 1 4 5 6 \n"
+                        "STARTED 2 1002\nDONE 2 6 1 3\n"
+                        "", true));
+  EQ(M.Files[0].Features, {1, 2, 3});
+  EQ(M.Files[1].Features, {4, 5, 6});
+  EQ(M.Files[2].Features, {1, 3, 6});
+  EXPECT_EQ(3U, M.Merge(&NewFiles));
+  EQ(NewFiles, {"B"});
+}
+
+TEST(Merge, Merge) {
+
+  Merge("3\n1\nA\nB\nC\n"
+        "STARTED 0 1000\nDONE 0 1 2 3\n"
+        "STARTED 1 1001\nDONE 1 4 5 6 \n"
+        "STARTED 2 1002\nDONE 2 6 1 3 \n",
+        {"B"}, 3);
+
+  Merge("3\n0\nA\nB\nC\n"
+        "STARTED 0 2000\nDONE 0 1 2 3\n"
+        "STARTED 1 1001\nDONE 1 4 5 6 \n"
+        "STARTED 2 1002\nDONE 2 6 1 3 \n",
+        {"A", "B", "C"}, 6);
+
+  Merge("4\n0\nA\nB\nC\nD\n"
+        "STARTED 0 2000\nDONE 0 1 2 3\n"
+        "STARTED 1 1101\nDONE 1 4 5 6 \n"
+        "STARTED 2 1102\nDONE 2 6 1 3 100 \n"
+        "STARTED 3 1000\nDONE 3 1  \n",
+        {"A", "B", "C", "D"}, 7);
+
+  Merge("4\n1\nA\nB\nC\nD\n"
+        "STARTED 0 2000\nDONE 0 4 5 6 7 8\n"
+        "STARTED 1 1100\nDONE 1 1 2 3 \n"
+        "STARTED 2 1100\nDONE 2 2 3 \n"
+        "STARTED 3 1000\nDONE 3 1  \n",
+        {"B", "D"}, 3);
+}

test/fuzz_test/Fuzzer/test/InitializeTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Make sure LLVMFuzzerInitialize is called.
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char *argv0;
+
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv) {
+  assert(*argc > 0);
+  argv0 = **argv;
+  fprintf(stderr, "LLVMFuzzerInitialize: %s\n", argv0);
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size == strlen(argv0) &&
+      !strncmp(reinterpret_cast<const char *>(Data), argv0, Size)) {
+    fprintf(stderr, "BINGO %s\n", argv0);
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/LeakTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test with a leak.
+#include <cstdint>
+#include <cstddef>
+
+static volatile void *Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && *Data == 'H') {
+    Sink = new int;
+    Sink = nullptr;
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/LeakTimeoutTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test with a leak.
+#include <cstdint>
+#include <cstddef>
+
+static volatile int *Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (!Size) return 0;
+  Sink = new int;
+  Sink = new int;
+  while (Sink) *Sink = 0;  // Infinite loop.
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/LoadTest.cpp

@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer: find interesting value of array index.
+#include <assert.h>
+#include <cstdint>
+#include <cstring>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+const int kArraySize = 1234567;
+int array[kArraySize];
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 8) return 0;
+  size_t a = 0;
+  memcpy(&a, Data, 8);
+  Sink = array[a % (kArraySize + 1)];
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/MemcmpTest.cpp

@@ -0,0 +1,31 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  // TODO: check other sizes.
+  if (Size >= 8 && memcmp(Data, "01234567", 8) == 0) {
+    if (Size >= 12 && memcmp(Data + 8, "ABCD", 4) == 0) {
+      if (Size >= 14 && memcmp(Data + 12, "XY", 2) == 0) {
+        if (Size >= 17 && memcmp(Data + 14, "KLM", 3) == 0) {
+          if (Size >= 27 && memcmp(Data + 17, "ABCDE-GHIJ", 10) == 0){
+            fprintf(stderr, "BINGO %zd\n", Size);
+            for (size_t i = 0; i < Size; i++) {
+              uint8_t C = Data[i];
+              if (C >= 32 && C < 127)
+                fprintf(stderr, "%c", C);
+            }
+            fprintf(stderr, "\n");
+            exit(1);
+          }
+        }
+      }
+    }
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/NthRunCrashTest.cpp

@@ -0,0 +1,18 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Crash on the N-th execution.
+#include <cstdint>
+#include <cstddef>
+#include <iostream>
+
+static int Counter;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Counter++ == 1000) {
+    std::cout << "BINGO; Found the target, exiting\n";
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/NullDerefOnEmptyTest.cpp

@@ -0,0 +1,19 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the empty string.
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int *Null = 0;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size == 0) {
+    std::cout << "Found the target, dereferencing NULL\n";
+    *Null = 1;
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/NullDerefTest.cpp

@@ -0,0 +1,26 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "Hi!".
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+static volatile int *Null = 0;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        std::cout << "Found the target, dereferencing NULL\n";
+        *Null = 1;
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/OneHugeAllocTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Tests OOM handling when there is a single large allocation.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+
+static volatile char *SinkPtr;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && Data[0] == 'H') {
+    if (Size > 1 && Data[1] == 'i') {
+      if (Size > 2 && Data[2] == '!') {
+        size_t kSize = (size_t)1 << 31;
+        char *p = new char[kSize];
+        memset(p, 0, kSize);
+        SinkPtr = p;
+        delete [] p;
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/OutOfMemorySingleLargeMallocTest.cpp

@@ -0,0 +1,27 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Tests OOM handling.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+
+static volatile char *SinkPtr;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && Data[0] == 'H') {
+    if (Size > 1 && Data[1] == 'i') {
+      if (Size > 2 && Data[2] == '!') {
+          size_t kSize = 0xff000000U;
+          char *p = new char[kSize];
+          SinkPtr = p;
+          delete [] p;
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/OutOfMemoryTest.cpp

@@ -0,0 +1,31 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Tests OOM handling.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+#include <thread>
+
+static volatile char *SinkPtr;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && Data[0] == 'H') {
+    if (Size > 1 && Data[1] == 'i') {
+      if (Size > 2 && Data[2] == '!') {
+        while (true) {
+          size_t kSize = 1 << 28;
+          char *p = new char[kSize];
+          memset(p, 0, kSize);
+          SinkPtr = p;
+          std::this_thread::sleep_for(std::chrono::seconds(1));
+        }
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/RepeatedBytesTest.cpp

@@ -0,0 +1,29 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find repeated bytes.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  // Looking for AAAAAAAAAAAAAAAAAAAAAA or some such.
+  size_t CurA = 0, MaxA = 0;
+  for (size_t i = 0; i < Size; i++) {
+    // Make sure there are no conditionals in the loop so that
+    // coverage can't help the fuzzer.
+    int EQ = Data[i] == 'A';
+    CurA = EQ * (CurA + 1);
+    int GT = CurA > MaxA;
+    MaxA = GT * CurA + (!GT) * MaxA;
+  }
+  if (MaxA >= 20) {
+    std::cout << "BINGO; Found the target (Max: " << MaxA << "), exiting\n";
+    exit(0);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/RepeatedMemcmp.cpp

@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int Matches = 0;
+  for (size_t i = 0; i + 2 < Size; i += 3) {
+    const char *Pat = i % 2 ? "foo" : "bar";
+    if (!memcmp(Data + i, Pat, 3))
+      Matches++;
+  }
+  if (Matches > 20) {
+    fprintf(stderr, "BINGO!\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/ShrinkControlFlowTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test that we can find the minimal item in the corpus (3 bytes: "FUZ").
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <cstdio>
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  int8_t Ids[256];
+  memset(Ids, -1, sizeof(Ids));
+  for (size_t i = 0; i < Size; i++)
+    if (Ids[Data[i]] == -1)
+      Ids[Data[i]] = i;
+  int F = Ids[(unsigned char)'F'];
+  int U = Ids[(unsigned char)'U'];
+  int Z = Ids[(unsigned char)'Z'];
+  if (F >= 0 && U > F && Z > U) {
+    Sink++;
+    //fprintf(stderr, "IDS: %d %d %d\n", F, U, Z);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/ShrinkValueProfileTest.cpp

@@ -0,0 +1,22 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test that we can find the minimal item in the corpus (3 bytes: "FUZ").
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <cstdio>
+
+static volatile uint32_t Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < sizeof(uint32_t)) return 0;
+  uint32_t X, Y;
+  size_t Offset = Size < 8 ? 0 : Size / 2;
+  memcpy(&X, Data + Offset, sizeof(uint32_t));
+  memcpy(&Y, "FUZZ", sizeof(uint32_t));
+  Sink = X == Y;
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SignedIntOverflowTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for signed-integer-overflow.
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+#include <climits>
+
+static volatile int Sink;
+static int Large = INT_MAX;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        Large++;  // int overflow.
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SimpleCmpTest.cpp

@@ -0,0 +1,46 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find several narrow ranges.
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+extern int AllLines[];
+
+bool PrintOnce(int Line) {
+  if (!AllLines[Line])
+    fprintf(stderr, "Seen line %d\n", Line);
+  AllLines[Line] = 1;
+  return true;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size != 22) return 0;
+  uint64_t x = 0;
+  int64_t  y = 0;
+  int32_t z = 0;
+  uint16_t a = 0;
+  memcpy(&x, Data, 8);  // 8
+  memcpy(&y, Data + 8, 8);  // 16
+  memcpy(&z, Data + 16, sizeof(z));  // 20
+  memcpy(&a, Data + 20, sizeof(a));  // 22
+
+  if (x > 1234567890 && PrintOnce(__LINE__) &&
+      x < 1234567895 && PrintOnce(__LINE__) &&
+      a == 0x4242 && PrintOnce(__LINE__) &&
+      y >= 987654321 && PrintOnce(__LINE__) &&
+      y <= 987654325 && PrintOnce(__LINE__) &&
+      z < -10000 && PrintOnce(__LINE__) &&
+      z >= -10005 && PrintOnce(__LINE__) &&
+      z != -10003 && PrintOnce(__LINE__) &&
+      true) {
+    fprintf(stderr, "BINGO; Found the target: size %zd (%zd, %zd, %d, %d), exiting.\n",
+            Size, x, y, z, a);
+    exit(1);
+  }
+  return 0;
+}
+
+int AllLines[__LINE__ + 1];  // Must be the last line.

test/fuzz_test/Fuzzer/test/SimpleDictionaryTest.cpp

@@ -0,0 +1,29 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer.
+// The fuzzer must find a string based on dictionary words:
+//   "Elvis"
+//   "Presley"
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+
+static volatile int Zero = 0;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  const char *Expected = "ElvisPresley";
+  if (Size < strlen(Expected)) return 0;
+  size_t Match = 0;
+  for (size_t i = 0; Expected[i]; i++)
+    if (Expected[i] + Zero == Data[i])
+      Match++;
+  if (Match == strlen(Expected)) {
+    std::cout << "BINGO; Found the target, exiting\n";
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SimpleHashTest.cpp

@@ -0,0 +1,40 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// This test computes a checksum of the data (all but the last 4 bytes),
+// and then compares the last 4 bytes with the computed value.
+// A fuzzer with cmp traces is expected to defeat this check.
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+// A modified jenkins_one_at_a_time_hash initialized by non-zero,
+// so that simple_hash(0) != 0. See also
+// https://en.wikipedia.org/wiki/Jenkins_hash_function
+static uint32_t simple_hash(const uint8_t *Data, size_t Size) {
+  uint32_t Hash = 0x12039854;
+  for (uint32_t i = 0; i < Size; i++) {
+    Hash += Data[i];
+    Hash += (Hash << 10);
+    Hash ^= (Hash >> 6);
+  }
+  Hash += (Hash << 3);
+  Hash ^= (Hash >> 11);
+  Hash += (Hash << 15);
+  return Hash;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 14)
+    return 0;
+
+  uint32_t Hash = simple_hash(&Data[0], Size - 4);
+  uint32_t Want = reinterpret_cast<const uint32_t *>(&Data[Size - 4])[0];
+  if (Hash != Want)
+    return 0;
+  fprintf(stderr, "BINGO; simple_hash defeated: %x == %x\n", (unsigned int)Hash,
+          (unsigned int)Want);
+  exit(1);
+  return 0;
+}

test/fuzz_test/Fuzzer/test/SimpleTest.cpp

@@ -0,0 +1,27 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "Hi!".
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        std::cout << "BINGO; Found the target, exiting\n";
+        exit(0);
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SimpleThreadedTest.cpp

@@ -0,0 +1,25 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Threaded test for a fuzzer. The fuzzer should find "H"
+#include <assert.h>
+#include <cstdint>
+#include <cstddef>
+#include <cstring>
+#include <iostream>
+#include <thread>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  auto C = [&] {
+    if (Size >= 2 && Data[0] == 'H') {
+        std::cout << "BINGO; Found the target, exiting\n";
+        abort();
+    }
+  };
+  std::thread T[] = {std::thread(C), std::thread(C), std::thread(C),
+                     std::thread(C), std::thread(C), std::thread(C)};
+  for (auto &X : T)
+    X.join();
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SingleMemcmpTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  char *S = (char*)Data;
+  if (Size >= 6 && !memcmp(S, "qwerty", 6)) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/SingleStrcmpTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  char *S = (char*)Data;
+  if (Size >= 7 && !strcmp(S, "qwerty")) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/SingleStrncmpTest.cpp

@@ -0,0 +1,17 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  char *S = (char*)Data;
+  if (Size >= 6 && !strncmp(S, "qwerty", 6)) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/SpamyTest.cpp

@@ -0,0 +1,21 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// The test spams to stderr and stdout.
+#include <assert.h>
+#include <cstdint>
+#include <cstdio>
+#include <cstddef>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  printf("PRINTF_STDOUT\n");
+  fflush(stdout);
+  fprintf(stderr, "PRINTF_STDERR\n");
+  std::cout << "STREAM_COUT\n";
+  std::cout.flush();
+  std::cerr << "STREAM_CERR\n";
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/StrcmpTest.cpp

@@ -0,0 +1,32 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Break through a series of strcmp.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cassert>
+
+bool Eq(const uint8_t *Data, size_t Size, const char *Str) {
+  char Buff[1024];
+  size_t Len = strlen(Str);
+  if (Size < Len) return false;
+  if (Len >= sizeof(Buff)) return false;
+  memcpy(Buff, (char*)Data, Len);
+  Buff[Len] = 0;
+  int res = strcmp(Buff, Str);
+  return res == 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Eq(Data, Size, "ABC") &&
+      Size >= 3 && Eq(Data + 3, Size - 3, "QWER") &&
+      Size >= 7 && Eq(Data + 7, Size - 7, "ZXCVN") &&
+      Size >= 14 && Data[13] == 42
+    ) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/StrncmpOOBTest.cpp

@@ -0,0 +1,21 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test that libFuzzer itself does not read out of bounds.
+#include <assert.h>
+#include <cstdint>
+#include <cstring>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 5) return 0;
+  const char *Ch = reinterpret_cast<const char *>(Data);
+  if (Ch[Size - 3] == 'a')
+    Sink = strncmp(Ch + Size - 3, "abcdefg", 6);
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/StrncmpTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find a particular string.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+static volatile int sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  // TODO: check other sizes.
+  char *S = (char*)Data;
+  if (Size >= 8 && strncmp(S, "123", 8))
+    sink = 1;
+  if (Size >= 8 && strncmp(S, "01234567", 8) == 0) {
+    if (Size >= 12 && strncmp(S + 8, "ABCD", 4) == 0) {
+      if (Size >= 14 && strncmp(S + 12, "XY", 2) == 0) {
+        if (Size >= 17 && strncmp(S + 14, "KLM", 3) == 0) {
+          fprintf(stderr, "BINGO\n");
+          exit(1);
+        }
+      }
+    }
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/StrstrTest.cpp

@@ -0,0 +1,28 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test strstr and strcasestr hooks.
+#include <string>
+#include <string.h>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+
+// Windows does not have strcasestr and memmem, so we are not testing them.
+#ifdef _WIN32
+#define strcasestr strstr
+#define memmem(a, b, c, d) true
+#endif
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 4) return 0;
+  std::string s(reinterpret_cast<const char*>(Data), Size);
+  if (strstr(s.c_str(), "FUZZ") &&
+      strcasestr(s.c_str(), "aBcD") &&
+      memmem(s.data(), s.size(), "kuku", 4)
+      ) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/SwapCmpTest.cpp

@@ -0,0 +1,34 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// The fuzzer must find several constants with swapped bytes.
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <cstdio>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 14) return 0;
+  uint64_t x = 0;
+  uint32_t y = 0;
+  uint16_t z = 0;
+  memcpy(&x, Data, sizeof(x));
+  memcpy(&y, Data + Size / 2, sizeof(y));
+  memcpy(&z, Data + Size - sizeof(z), sizeof(z));
+
+  x = __builtin_bswap64(x);
+  y = __builtin_bswap32(y);
+  z = __builtin_bswap16(z);
+
+  if (x == 0x46555A5A5A5A5546ULL &&
+      z == 0x4F4B &&
+      y == 0x66757A7A &&
+      true
+      ) {
+    if (Data[Size - 3] == 'z') {
+      fprintf(stderr, "BINGO; Found the target\n");
+      exit(1);
+    }
+  }
+  return 0;
+}

test/fuzz_test/Fuzzer/test/Switch2Test.cpp

@@ -0,0 +1,35 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the interesting switch value.
+#include <cstdint>
+#include <cstdlib>
+#include <cstdio>
+#include <cstring>
+#include <cstddef>
+
+int Switch(int a) {
+  switch(a) {
+    case 100001: return 1;
+    case 100002: return 2;
+    case 100003: return 4;
+  }
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  const int N = 3;
+  if (Size < N * sizeof(int)) return 0;
+  int Res = 0;
+  for (int i = 0; i < N; i++) {
+    int X;
+    memcpy(&X, Data + i * sizeof(int), sizeof(int));
+    Res += Switch(X);
+  }
+  if (Res == 5 || Res == 3 || Res == 6 || Res == 7) {
+    fprintf(stderr, "BINGO; Found the target, exiting; Res=%d\n", Res);
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/SwitchTest.cpp

@@ -0,0 +1,58 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the interesting switch value.
+#include <cstdint>
+#include <cstdlib>
+#include <cstdio>
+#include <cstring>
+#include <cstddef>
+
+static volatile int Sink;
+
+template<class T>
+bool Switch(const uint8_t *Data, size_t Size) {
+  T X;
+  if (Size < sizeof(X)) return false;
+  memcpy(&X, Data, sizeof(X));
+  switch (X) {
+    case 1: Sink = __LINE__; break;
+    case 101: Sink = __LINE__; break;
+    case 1001: Sink = __LINE__; break;
+    case 10001: Sink = __LINE__; break;
+//    case 100001: Sink = __LINE__; break;
+//    case 1000001: Sink = __LINE__; break;
+    case 10000001: Sink = __LINE__; break;
+    case 100000001: return true;
+  }
+  return false;
+}
+
+bool ShortSwitch(const uint8_t *Data, size_t Size) {
+  short X;
+  if (Size < sizeof(short)) return false;
+  memcpy(&X, Data, sizeof(short));
+  switch(X) {
+    case 42: Sink = __LINE__; break;
+    case 402: Sink = __LINE__; break;
+    case 4002: Sink = __LINE__; break;
+    case 5002: Sink = __LINE__; break;
+    case 7002: Sink = __LINE__; break;
+    case 9002: Sink = __LINE__; break;
+    case 14002: Sink = __LINE__; break;
+    case 21402: return true;
+  }
+  return false;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size >= 4  && Switch<int>(Data, Size) &&
+      Size >= 12 && Switch<uint64_t>(Data + 4, Size - 4) &&
+      Size >= 14 && ShortSwitch(Data + 12, 2)
+    ) {
+    fprintf(stderr, "BINGO; Found the target, exiting\n");
+    exit(1);
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/ThreadedLeakTest.cpp

@@ -0,0 +1,18 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// The fuzzer should find a leak in a non-main thread.
+#include <cstdint>
+#include <cstddef>
+#include <thread>
+
+static volatile int *Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size == 0) return 0;
+  if (Data[0] != 'F') return 0;
+  std::thread T([&] { Sink = new int; });
+  T.join();
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/ThreadedTest.cpp

@@ -0,0 +1,26 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Threaded test for a fuzzer. The fuzzer should not crash.
+#include <assert.h>
+#include <cstdint>
+#include <cstddef>
+#include <cstring>
+#include <thread>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size < 8) return 0;
+  assert(Data);
+  auto C = [&] {
+    size_t Res = 0;
+    for (size_t i = 0; i < Size / 2; i++)
+      Res += memcmp(Data, Data + Size / 2, 4);
+    return Res;
+  };
+  std::thread T[] = {std::thread(C), std::thread(C), std::thread(C),
+                     std::thread(C), std::thread(C), std::thread(C)};
+  for (auto &X : T)
+    X.join();
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/TimeoutEmptyTest.cpp

@@ -0,0 +1,14 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the empty string.
+#include <cstdint>
+#include <cstddef>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  static volatile int Zero = 0;
+  if (!Size)
+    while(!Zero)
+      ;
+  return 0;
+}

test/fuzz_test/Fuzzer/test/TimeoutTest.cpp

@@ -0,0 +1,26 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Simple test for a fuzzer. The fuzzer must find the string "Hi!".
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+static volatile int Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        Sink = 2;
+        while (Sink)
+          ;
+      }
+    }
+  }
+  return 0;
+}
+

test/fuzz_test/Fuzzer/test/TraceMallocTest.cpp

@@ -0,0 +1,27 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Tests -trace_malloc
+#include <assert.h>
+#include <cstdint>
+#include <cstdlib>
+#include <cstddef>
+#include <iostream>
+
+int *Ptr;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (!Size) return 0;
+  if (*Data == 1) {
+    delete Ptr;
+    Ptr = nullptr;
+  } else if (*Data == 2) {
+    delete Ptr;
+    Ptr = new int;
+  } else if (*Data == 3) {
+    if (!Ptr)
+      Ptr = new int;
+  }
+  return 0;
+}
+