| //===- 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)))); |
| } |
| |
| void __sanitizer_cov_trace_pc_indir(int *) { |
| // Stub to allow linking with code built with |
| // -fsanitize=indirect-calls,trace-pc. |
| // This isn't used currently. |
| } |
| } |