[libFuzzer] refactoring around PCMap, NFC

llvm-svn: 278825

1 files changed, 10 insertions, 31 deletions

diff --git a/llvm/lib/Fuzzer/FuzzerTracePC.cpp b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
index 46c43d0c17f..53341d3632e 100644
--- a/llvm/lib/Fuzzer/FuzzerTracePC.cpp
+++ b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
@@ -16,43 +16,22 @@
 
 namespace fuzzer {
 
-void PcCoverageMap::Reset() { memset(Map, 0, sizeof(Map)); }
+static size_t PreviouslyComputedPCHash;
+static ValueBitMap CurrentPCMap;
 
-void PcCoverageMap::Update(uintptr_t Addr) {
-  uintptr_t Idx = Addr % kMapSizeInBits;
-  uintptr_t WordIdx = Idx / kBitsInWord;
-  uintptr_t BitIdx = Idx % kBitsInWord;
-  Map[WordIdx] |= 1UL << BitIdx;
-}
-
-size_t PcCoverageMap::MergeFrom(const PcCoverageMap &Other) {
-  uintptr_t Res = 0;
-  for (size_t i = 0; i < kMapSizeInWords; i++)
-    Res += __builtin_popcountl(Map[i] |= Other.Map[i]);
-  return Res;
-}
-
-static PcCoverageMap CurrentMap;
-static thread_local uintptr_t Prev;
-
-void PcMapResetCurrent() {
-  if (Prev) {
-    Prev = 0;
-    CurrentMap.Reset();
-  }
-}
-
-size_t PcMapMergeInto(PcCoverageMap *Map) {
-  if (!Prev)
+// Merges CurrentPCMap into M, returns the number of new bits.
+size_t PCMapMergeFromCurrent(ValueBitMap &M) {
+  if (!PreviouslyComputedPCHash)
     return 0;
-  return Map->MergeFrom(CurrentMap);
+  PreviouslyComputedPCHash = 0;
+  return M.MergeFrom(CurrentPCMap);
 }
 
 static void HandlePC(uint32_t PC) {
   // We take 12 bits of PC and mix it with the previous PCs.
-  uintptr_t Next = (Prev << 5) ^ (PC & 4095);
-  CurrentMap.Update(Next);
-  Prev = Next;
+  uintptr_t Next = (PreviouslyComputedPCHash << 5) ^ (PC & 4095);
+  CurrentPCMap.AddValue(Next);
+  PreviouslyComputedPCHash = Next;
 }
 
 } // namespace fuzzer