[libFuzzer] allow -print_funcs=N: N is the max number of new covered function printed

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@311945 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 13 insertions, 6 deletions

diff --git a/lib/fuzzer/FuzzerFlags.def b/lib/fuzzer/FuzzerFlags.def
index df52377bf..790b5783d 100644
--- a/lib/fuzzer/FuzzerFlags.def
+++ b/lib/fuzzer/FuzzerFlags.def
@@ -91,7 +91,8 @@ FUZZER_FLAG_STRING(exact_artifact_path,
                    "and will not use checksum in the file name. Do not "
                    "use the same path for several parallel processes.")
 FUZZER_FLAG_INT(print_pcs, 0, "If 1, print out newly covered PCs.")
-FUZZER_FLAG_INT(print_funcs, 1, "If 1, print out newly covered functions.")
+FUZZER_FLAG_INT(print_funcs, 2, "If >=1, print out at most this number of "
+                                "newly covered functions.")
 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.")
diff --git a/lib/fuzzer/FuzzerOptions.h b/lib/fuzzer/FuzzerOptions.h
index d38724209..bfac3b685 100644
--- a/lib/fuzzer/FuzzerOptions.h
+++ b/lib/fuzzer/FuzzerOptions.h
@@ -47,7 +47,7 @@ struct FuzzingOptions {
   bool SaveArtifacts = true;
   bool PrintNEW = true; // Print a status line when new units are found;
   bool PrintNewCovPcs = false;
-  bool PrintNewCovFuncs = false;
+  int PrintNewCovFuncs = 0;
   bool PrintFinalStats = false;
   bool PrintCorpusStats = false;
   bool PrintCoverage = false;
diff --git a/lib/fuzzer/FuzzerTracePC.cpp b/lib/fuzzer/FuzzerTracePC.cpp
index 831316aa3..78f0d4171 100644
--- a/lib/fuzzer/FuzzerTracePC.cpp
+++ b/lib/fuzzer/FuzzerTracePC.cpp
@@ -143,6 +143,7 @@ void TracePC::HandleCallerCallee(uintptr_t Caller, uintptr_t Callee) {
 }
 
 void TracePC::UpdateObservedPCs() {
+  Vector<uintptr_t> CoveredFuncs;
   auto ObservePC = [&](uintptr_t PC) {
     if (ObservedPCs.insert(PC).second && DoPrintNewPCs)
       PrintPC("\tNEW_PC: %p %F %L\n", "\tNEW_PC: %p\n", PC + 1);
@@ -150,8 +151,8 @@ void TracePC::UpdateObservedPCs() {
 
   auto Observe = [&](const PCTableEntry &TE) {
     if (TE.PCFlags & 1)
-      if (ObservedFuncs.insert(TE.PC).second && DoPrintNewFuncs)
-        PrintPC("\tNEW_FUNC: %p %F %L\n", "\tNEW_PC: %p\n", TE.PC + 1);
+      if (ObservedFuncs.insert(TE.PC).second && NumPrintNewFuncs)
+        CoveredFuncs.push_back(TE.PC);
     ObservePC(TE.PC);
   };
 
@@ -186,6 +187,11 @@ void TracePC::UpdateObservedPCs() {
       if (P[Idx])
         ObservePC((uintptr_t)Idx);
   }
+
+  for (size_t i = 0, N = Min(CoveredFuncs.size(), NumPrintNewFuncs); i < N; i++) {
+    Printf("\tNEW_FUNC[%zd/%zd]: ", i, CoveredFuncs.size());
+    PrintPC("%p %F %L\n", "%p\n", CoveredFuncs[i] + 1);
+  }
 }
 
 inline ALWAYS_INLINE uintptr_t GetPreviousInstructionPc(uintptr_t PC) {
diff --git a/lib/fuzzer/FuzzerTracePC.h b/lib/fuzzer/FuzzerTracePC.h
index 9c23ef6b5..54172608d 100644
--- a/lib/fuzzer/FuzzerTracePC.h
+++ b/lib/fuzzer/FuzzerTracePC.h
@@ -82,7 +82,7 @@ class TracePC {
   void SetUseCounters(bool UC) { UseCounters = UC; }
   void SetUseValueProfile(bool VP) { UseValueProfile = VP; }
   void SetPrintNewPCs(bool P) { DoPrintNewPCs = P; }
-  void SetPrintNewFuncs(bool P) { DoPrintNewFuncs = P; }
+  void SetPrintNewFuncs(size_t P) { NumPrintNewFuncs = P; }
   void UpdateObservedPCs();
   template <class Callback> void CollectFeatures(Callback CB) const;
 
@@ -134,7 +134,7 @@ private:
   bool UseCounters = false;
   bool UseValueProfile = false;
   bool DoPrintNewPCs = false;
-  bool DoPrintNewFuncs = false;
+  size_t NumPrintNewFuncs = 0;
 
   struct Module {
     uint32_t *Start, *Stop;