// This module implements __sanitizer_cov_trace_pc, a callback required
// for -fsanitize-coverage=trace-pc instrumentation.
//
-// Experimental and not yet tuned for performance.
//===----------------------------------------------------------------------===//
#include "FuzzerInternal.h"
namespace fuzzer {
-static const size_t kMapSize = 65371; // Prime.
-static uint8_t CurMap[kMapSize];
-static uint8_t CombinedMap[kMapSize];
+static const size_t kMapSizeInBits = 65371; // Prime.
+static const size_t kMapSizeInBitsAligned = 65536; // 2^16
+static const size_t kBitsInWord =(sizeof(uintptr_t) * 8);
+static const size_t kMapSizeInWords = kMapSizeInBitsAligned / kBitsInWord;
+static uintptr_t CurrentMap[kMapSizeInWords] __attribute__((aligned(512)));
+static uintptr_t CombinedMap[kMapSizeInWords] __attribute__((aligned(512)));
static size_t CombinedMapSize;
static thread_local uintptr_t Prev;
void PcMapResetCurrent() {
if (Prev) {
Prev = 0;
- memset(CurMap, 0, sizeof(CurMap));
+ memset(CurrentMap, 0, sizeof(CurrentMap));
}
}
-// TODO: speed this up.
void PcMapMergeCurrentToCombined() {
if (!Prev) return;
uintptr_t Res = 0;
- for (size_t i = 0; i < kMapSize; i++) {
- uint8_t p = (CombinedMap[i] |= CurMap[i]);
- CurMap[i] = 0;
- Res += p != 0;
- }
+ for (size_t i = 0; i < kMapSizeInWords; i++)
+ Res += __builtin_popcountl(CombinedMap[i] |= CurrentMap[i]);
CombinedMapSize = Res;
}
size_t PcMapCombinedSize() { return CombinedMapSize; }
-static void HandlePC(uintptr_t PC) {
+static void HandlePC(uint32_t PC) {
// We take 12 bits of PC and mix it with the previous PCs.
- uintptr_t Idx = (Prev << 5) ^ (PC & 4095);
- CurMap[Idx % kMapSize] = 1;
- Prev = Idx;
+ uintptr_t Next = (Prev << 5) ^ (PC & 4095);
+ uintptr_t Idx = Next % kMapSizeInBits;
+ uintptr_t WordIdx = Idx / kBitsInWord;
+ uintptr_t BitIdx = Idx % kBitsInWord;
+ CurrentMap[WordIdx] |= 1UL << BitIdx;
+ Prev = Next;
}
} // namespace fuzzer
extern "C" void __sanitizer_cov_trace_pc() {
- fuzzer::HandlePC(reinterpret_cast<uintptr_t>(__builtin_return_address(0)));
+ fuzzer::HandlePC(static_cast<uint32_t>(
+ reinterpret_cast<uintptr_t>(__builtin_return_address(0))));
}
-//uintptr_t __sanitizer_get_total_unique_coverage() { return 0; }
-//uintptr_t __sanitizer_get_number_of_counters() { return 0; }