[libFuzzer] speedup TracePC::FinalizeTrace
llvm-svn: 282562
diff --git a/llvm/lib/Fuzzer/FuzzerTracePC.cpp b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
index d533eac..9789d5d 100644
--- a/llvm/lib/Fuzzer/FuzzerTracePC.cpp
+++ b/llvm/lib/Fuzzer/FuzzerTracePC.cpp
@@ -70,20 +70,27 @@
void TracePC::FinalizeTrace() {
if (TotalPCCoverage) {
- for (size_t Idx = 1, N = Min(kNumCounters, NumGuards + 1); Idx < N;
- Idx++) {
- uint8_t Counter = Counters[Idx];
- if (!Counter) continue;
- Counters[Idx] = 0;
- unsigned Bit = 0;
- /**/ if (Counter >= 128) Bit = 7;
- else if (Counter >= 32) Bit = 6;
- else if (Counter >= 16) Bit = 5;
- else if (Counter >= 8) Bit = 4;
- else if (Counter >= 4) Bit = 3;
- else if (Counter >= 3) Bit = 2;
- else if (Counter >= 2) Bit = 1;
- CounterMap.AddValue(Idx * 8 + Bit);
+ const size_t Step = 8;
+ assert(reinterpret_cast<uintptr_t>(Counters) % Step == 0);
+ size_t N = Min(kNumCounters, NumGuards + 1);
+ N = (N + Step - 1) & ~(Step - 1); // Round up.
+ for (size_t Idx = 0; Idx < N; Idx += Step) {
+ uint64_t Bundle = *reinterpret_cast<uint64_t*>(&Counters[Idx]);
+ if (!Bundle) continue;
+ for (size_t i = Idx; i < Idx + Step; i++) {
+ uint8_t Counter = (Bundle >> (i * 8)) & 0xff;
+ if (!Counter) continue;
+ Counters[i] = 0;
+ unsigned Bit = 0;
+ /**/ if (Counter >= 128) Bit = 7;
+ else if (Counter >= 32) Bit = 6;
+ else if (Counter >= 16) Bit = 5;
+ else if (Counter >= 8) Bit = 4;
+ else if (Counter >= 4) Bit = 3;
+ else if (Counter >= 3) Bit = 2;
+ else if (Counter >= 2) Bit = 1;
+ CounterMap.AddValue(i * 8 + Bit);
+ }
}
}
}