forked from OSchip/llvm-project
64 lines
1.7 KiB
C++
64 lines
1.7 KiB
C++
//===- FuzzerTracePC.cpp - PC tracing--------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
// Trace PCs.
|
|
// This module implements __sanitizer_cov_trace_pc, a callback required
|
|
// for -fsanitize-coverage=trace-pc instrumentation.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "FuzzerInternal.h"
|
|
|
|
namespace fuzzer {
|
|
|
|
void PcCoverageMap::Reset() { memset(Map, 0, sizeof(Map)); }
|
|
|
|
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)
|
|
return 0;
|
|
return Map->MergeFrom(CurrentMap);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
} // namespace fuzzer
|
|
|
|
extern "C" void __sanitizer_cov_trace_pc() {
|
|
fuzzer::HandlePC(static_cast<uint32_t>(
|
|
reinterpret_cast<uintptr_t>(__builtin_return_address(0))));
|
|
}
|