[libFuzzer] refactor the way we choose the element to cross-over with, NFC (expected1); add a flag -seed_inputs= to pass extra seed inputs as file paths, not dirs

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@353494 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 43 insertions, 19 deletions

diff --git a/lib/fuzzer/FuzzerDriver.cpp b/lib/fuzzer/FuzzerDriver.cpp
index 0f8389cb3..2bc895d00 100644
--- a/lib/fuzzer/FuzzerDriver.cpp
+++ b/lib/fuzzer/FuzzerDriver.cpp
@@ -732,7 +732,19 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
     exit(0);
   }
 
-  F->Loop(*Inputs);
+  // Parse -seed_inputs=file1,file2,...
+  Vector<std::string> ExtraSeedFiles;
+  if (Flags.seed_inputs) {
+    std::string s = Flags.seed_inputs;
+    size_t comma_pos;
+    while ((comma_pos = s.find_last_of(',')) != std::string::npos) {
+      ExtraSeedFiles.push_back(s.substr(comma_pos + 1));
+      s = s.substr(0, comma_pos);
+    }
+    ExtraSeedFiles.push_back(s);
+  }
+
+  F->Loop(*Inputs, ExtraSeedFiles);
 
   if (Flags.verbosity)
     Printf("Done %zd runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
diff --git a/lib/fuzzer/FuzzerFlags.def b/lib/fuzzer/FuzzerFlags.def
index 198e4dd91..c762bafa7 100644
--- a/lib/fuzzer/FuzzerFlags.def
+++ b/lib/fuzzer/FuzzerFlags.def
@@ -20,6 +20,8 @@ FUZZER_FLAG_INT(len_control, 100, "Try generating small inputs first, "
   "then try larger inputs over time.  Specifies the rate at which the length "
   "limit is increased (smaller == faster).  If 0, immediately try inputs with "
   "size up to max_len.")
+FUZZER_FLAG_STRING(seed_inputs, "A comma-separated list of input files "
+  "to use as an additional seed corpus")
 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.")
diff --git a/lib/fuzzer/FuzzerInternal.h b/lib/fuzzer/FuzzerInternal.h
index 9950445bc..e934e1114 100644
--- a/lib/fuzzer/FuzzerInternal.h
+++ b/lib/fuzzer/FuzzerInternal.h
@@ -35,8 +35,10 @@ public:
   Fuzzer(UserCallback CB, InputCorpus &Corpus, MutationDispatcher &MD,
          FuzzingOptions Options);
   ~Fuzzer();
-  void Loop(const Vector<std::string> &CorpusDirs);
-  void ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs);
+  void Loop(const Vector<std::string> &CorpusDirs,
+            const Vector<std::string> &ExtraSeedFiles);
+  void ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs,
+                                 const Vector<std::string> &ExtraSeedFiles);
   void MinimizeCrashLoop(const Unit &U);
   void RereadOutputCorpus(size_t MaxSize);
 
diff --git a/lib/fuzzer/FuzzerLoop.cpp b/lib/fuzzer/FuzzerLoop.cpp
index fb5aa1f11..58fd5c3e9 100644
--- a/lib/fuzzer/FuzzerLoop.cpp
+++ b/lib/fuzzer/FuzzerLoop.cpp
@@ -630,6 +630,8 @@ void Fuzzer::MutateAndTestOne() {
   MD.StartMutationSequence();
 
   auto &II = Corpus.ChooseUnitToMutate(MD.GetRand());
+  if (Options.DoCrossOver)
+    MD.SetCrossOverWith(&Corpus.ChooseUnitToMutate(MD.GetRand()).U);
   const auto &U = II.U;
   memcpy(BaseSha1, II.Sha1, sizeof(BaseSha1));
   assert(CurrentUnitData);
@@ -688,7 +690,9 @@ void Fuzzer::PurgeAllocator() {
   LastAllocatorPurgeAttemptTime = system_clock::now();
 }
 
-void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
+void Fuzzer::ReadAndExecuteSeedCorpora(
+    const Vector<std::string> &CorpusDirs,
+    const Vector<std::string> &ExtraSeedFiles) {
   const size_t kMaxSaneLen = 1 << 20;
   const size_t kMinDefaultLen = 4096;
   Vector<SizedFile> SizedFiles;
@@ -702,6 +706,11 @@ void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
            Dir.c_str());
     LastNumFiles = SizedFiles.size();
   }
+  // Add files from -seed_inputs.
+  for (auto &File : ExtraSeedFiles)
+    if (auto Size = FileSize(File))
+      SizedFiles.push_back({File, Size});
+
   for (auto &File : SizedFiles) {
     MaxSize = Max(File.Size, MaxSize);
     MinSize = Min(File.Size, MinSize);
@@ -761,14 +770,13 @@ void Fuzzer::ReadAndExecuteSeedCorpora(const Vector<std::string> &CorpusDirs) {
   }
 }
 
-void Fuzzer::Loop(const Vector<std::string> &CorpusDirs) {
-  ReadAndExecuteSeedCorpora(CorpusDirs);
+void Fuzzer::Loop(const Vector<std::string> &CorpusDirs,
+                  const Vector<std::string> &ExtraSeedFiles) {
+  ReadAndExecuteSeedCorpora(CorpusDirs, ExtraSeedFiles);
   DFT.Clear();  // No need for DFT any more.
   TPC.SetPrintNewPCs(Options.PrintNewCovPcs);
   TPC.SetPrintNewFuncs(Options.PrintNewCovFuncs);
   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() >=
diff --git a/lib/fuzzer/FuzzerMutate.cpp b/lib/fuzzer/FuzzerMutate.cpp
index 6dc2eccdb..92e469f4c 100644
--- a/lib/fuzzer/FuzzerMutate.cpp
+++ b/lib/fuzzer/FuzzerMutate.cpp
@@ -8,12 +8,12 @@
 // Mutate a test input.
 //===----------------------------------------------------------------------===//
 
-#include "FuzzerMutate.h"
-#include "FuzzerCorpus.h"
 #include "FuzzerDefs.h"
 #include "FuzzerExtFunctions.h"
 #include "FuzzerIO.h"
+#include "FuzzerMutate.h"
 #include "FuzzerOptions.h"
+#include "FuzzerTracePC.h"
 
 namespace fuzzer {
 
@@ -72,10 +72,10 @@ size_t MutationDispatcher::Mutate_Custom(uint8_t *Data, size_t Size,
 
 size_t MutationDispatcher::Mutate_CustomCrossOver(uint8_t *Data, size_t Size,
                                                   size_t MaxSize) {
-  if (!Corpus || Corpus->size() < 2 || Size == 0)
+  if (Size == 0)
     return 0;
-  size_t Idx = Rand(Corpus->size());
-  const Unit &Other = (*Corpus)[Idx];
+  if (!CrossOverWith) return 0;
+  const Unit &Other = *CrossOverWith;
   if (Other.empty())
     return 0;
   CustomCrossOverInPlaceHere.resize(MaxSize);
@@ -421,9 +421,9 @@ size_t MutationDispatcher::Mutate_ChangeBinaryInteger(uint8_t *Data,
 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 (Size == 0) return 0;
+  if (!CrossOverWith) return 0;
+  const Unit &O = *CrossOverWith;
   if (O.empty()) return 0;
   MutateInPlaceHere.resize(MaxSize);
   auto &U = MutateInPlaceHere;
diff --git a/lib/fuzzer/FuzzerMutate.h b/lib/fuzzer/FuzzerMutate.h
index 33064d7a7..6cbce8027 100644
--- a/lib/fuzzer/FuzzerMutate.h
+++ b/lib/fuzzer/FuzzerMutate.h
@@ -63,7 +63,7 @@ public:
   /// 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.
+  /// CrossOver Data with CrossOverWith.
   size_t Mutate_CrossOver(uint8_t *Data, size_t Size, size_t MaxSize);
 
   /// Applies one of the configured mutations.
@@ -88,7 +88,7 @@ public:
 
   void PrintRecommendedDictionary();
 
-  void SetCorpus(const InputCorpus *Corpus) { this->Corpus = Corpus; }
+  void SetCrossOverWith(const Unit *U) { CrossOverWith = U; }
 
   Random &GetRand() { return Rand; }
 
@@ -139,7 +139,7 @@ public:
   DictionaryEntry CmpDictionaryEntriesDeque[kCmpDictionaryEntriesDequeSize];
   size_t CmpDictionaryEntriesDequeIdx = 0;
 
-  const InputCorpus *Corpus = nullptr;
+  const Unit *CrossOverWith = nullptr;
   Vector<uint8_t> MutateInPlaceHere;
   Vector<uint8_t> MutateWithMaskTemp;
   // CustomCrossOver needs its own buffer as a custom implementation may call