[libFuzzer] properly reset the guards when reseting the coverage. Also try to fix check-fuzzer on the bot

llvm-svn: 281814

3 files changed, 12 insertions, 1 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerInternal.h b/llvm/lib/Fuzzer/FuzzerInternal.h
index 69b38abc26f..3cecd21ab46 100644
--- a/llvm/lib/Fuzzer/FuzzerInternal.h
+++ b/llvm/lib/Fuzzer/FuzzerInternal.h
@@ -380,6 +380,7 @@ class TracePC {
     NumNewPCs = 0;
     CounterMap.Reset();
     TotalCoverageMap.Reset();
+    ResetGuards();
   }
 
   void PrintModuleInfo();
@@ -394,6 +395,8 @@ private:
   size_t NumNewPCs = 0;
   void AddNewPC(uintptr_t PC) { NewPCs[(NumNewPCs++) % kMaxNewPCs] = PC; }
 
+  void ResetGuards();
+
   struct Module {
     uint64_t *Start, *Stop;
   };
diff --git a/llvm/lib/Fuzzer/FuzzerTracePC.cpp b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
index 8fa9257c23b..dbc136a8cb2 100644
--- a/llvm/lib/Fuzzer/FuzzerTracePC.cpp
+++ b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
@@ -34,6 +34,8 @@ void TracePC::HandleTrace(uint64_t *Guard, uintptr_t PC) {
     }
     if (Counter < 255)
       Value++;
+    else
+      Value |= kBit63;
   } else {
     Value |= kBit63;
     TotalCoverage++;
@@ -60,6 +62,12 @@ void TracePC::PrintModuleInfo() {
   Printf("\n");
 }
 
+void TracePC::ResetGuards() {
+  for (size_t M = 0; M < NumModules; M++)
+    for (uint64_t *X = Modules[M].Start; X < Modules[M].Stop; X++)
+      *X = (*X >> 32) << 32;
+}
+
 void TracePC::FinalizeTrace() {
   if (UseCounters && TotalCoverage) {
     for (size_t M = 0; M < NumModules; M++) {
diff --git a/llvm/lib/Fuzzer/test/trace-pc/CMakeLists.txt b/llvm/lib/Fuzzer/test/trace-pc/CMakeLists.txt
index c4e4e9c29d4..27a8b0f91b7 100644
--- a/llvm/lib/Fuzzer/test/trace-pc/CMakeLists.txt
+++ b/llvm/lib/Fuzzer/test/trace-pc/CMakeLists.txt
@@ -36,4 +36,4 @@ set_target_properties(LLVMFuzzer-DSO1 PROPERTIES LIBRARY_OUTPUT_DIRECTORY
 set_target_properties(LLVMFuzzer-DSO2 PROPERTIES LIBRARY_OUTPUT_DIRECTORY
   "${CMAKE_BINARY_DIR}/lib/Fuzzer/lib")
 
-set(TestBinaries ${TestBinaries} LLVMFuzzer-DSOTest)
+set(TestBinaries ${TestBinaries} LLVMFuzzer-DSOTest PARENT_SCOPE)