[libFuzzer] add option -report_slow_units=Nsec to control when slow units are printed

llvm-svn: 244152

4 files changed, 8 insertions, 3 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerDriver.cpp b/llvm/lib/Fuzzer/FuzzerDriver.cpp
index c0f8220ad65..7f3ec7ba2ed 100644
--- a/llvm/lib/Fuzzer/FuzzerDriver.cpp
+++ b/llvm/lib/Fuzzer/FuzzerDriver.cpp
@@ -247,6 +247,7 @@ int FuzzerDriver(int argc, char **argv, UserSuppliedFuzzer &USF) {
   if (Flags.sync_command)
     Options.SyncCommand = Flags.sync_command;
   Options.SyncTimeout = Flags.sync_timeout;
+  Options.ReportSlowUnits = Flags.report_slow_units;
   Fuzzer F(USF, Options);
 
   if (Flags.apply_tokens)
diff --git a/llvm/lib/Fuzzer/FuzzerFlags.def b/llvm/lib/Fuzzer/FuzzerFlags.def
index 742f672e201..ac3ac6ef3f8 100644
--- a/llvm/lib/Fuzzer/FuzzerFlags.def
+++ b/llvm/lib/Fuzzer/FuzzerFlags.def
@@ -58,3 +58,5 @@ FUZZER_FLAG_STRING(sync_command, "Execute an external command "
                                  "\"<sync_command> <test_corpus>\" "
                                  "to synchronize the test corpus.")
 FUZZER_FLAG_INT(sync_timeout, 600, "Minimum timeout between syncs.")
+FUZZER_FLAG_INT(report_slow_units, 10,
+    "Report slowest units if they run for more than this number of seconds.")
diff --git a/llvm/lib/Fuzzer/FuzzerInternal.h b/llvm/lib/Fuzzer/FuzzerInternal.h
index cc86c361460..610b4375f24 100644
--- a/llvm/lib/Fuzzer/FuzzerInternal.h
+++ b/llvm/lib/Fuzzer/FuzzerInternal.h
@@ -79,6 +79,7 @@ class Fuzzer {
     int PreferSmallDuringInitialShuffle = -1;
     size_t MaxNumberOfRuns = ULONG_MAX;
     int SyncTimeout = 600;
+    int ReportSlowUnits = 10;
     std::string OutputCorpus;
     std::string SyncCommand;
     std::vector<std::string> Tokens;
diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index 5e8e2e4aae3..69b49b025a0 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -159,12 +159,13 @@ size_t Fuzzer::RunOne(const Unit &U) {
   auto UnitStopTime = system_clock::now();
   auto TimeOfUnit =
       duration_cast<seconds>(UnitStopTime - UnitStartTime).count();
-  if (TimeOfUnit > TimeOfLongestUnitInSeconds) {
+  if (TimeOfUnit > TimeOfLongestUnitInSeconds &&
+      TimeOfUnit >= Options.ReportSlowUnits) {
     TimeOfLongestUnitInSeconds = TimeOfUnit;
-    Printf("Longest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
+    Printf("Slowest unit: %zd s:\n", TimeOfLongestUnitInSeconds);
     if (U.size() <= kMaxUnitSizeToPrint)
       Print(U, "\n");
-    WriteUnitToFileWithPrefix(U, "long-running-unit-");
+    WriteUnitToFileWithPrefix(U, "slow-unit-");
   }
   return Res;
 }