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159 lines
4.6 KiB
C++
159 lines
4.6 KiB
C++
//===- FuzzerTracePC.h - Internal header for the Fuzzer ---------*- C++ -* ===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// fuzzer::TracePC
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_FUZZER_TRACE_PC
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#define LLVM_FUZZER_TRACE_PC
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#include "FuzzerDefs.h"
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#include "FuzzerValueBitMap.h"
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#include <set>
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namespace fuzzer {
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// TableOfRecentCompares (TORC) remembers the most recently performed
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// comparisons of type T.
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// We record the arguments of CMP instructions in this table unconditionally
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// because it seems cheaper this way than to compute some expensive
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// conditions inside __sanitizer_cov_trace_cmp*.
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// After the unit has been executed we may decide to use the contents of
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// this table to populate a Dictionary.
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template<class T, size_t kSizeT>
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struct TableOfRecentCompares {
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static const size_t kSize = kSizeT;
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struct Pair {
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T A, B;
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};
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void Insert(size_t Idx, T Arg1, T Arg2) {
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Idx = Idx % kSize;
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Table[Idx].A = Arg1;
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Table[Idx].B = Arg2;
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}
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Pair Get(size_t I) { return Table[I % kSize]; }
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Pair Table[kSize];
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};
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class TracePC {
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public:
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static const size_t kFeatureSetSize = ValueBitMap::kNumberOfItems;
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void HandleTrace(uint32_t *guard, uintptr_t PC);
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void HandleInit(uint32_t *start, uint32_t *stop);
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void HandleCallerCallee(uintptr_t Caller, uintptr_t Callee);
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void HandleValueProfile(size_t Value) { ValueProfileMap.AddValue(Value); }
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template <class T> void HandleCmp(void *PC, T Arg1, T Arg2);
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size_t GetTotalPCCoverage();
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void SetUseCounters(bool UC) { UseCounters = UC; }
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void SetUseValueProfile(bool VP) { UseValueProfile = VP; }
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void SetPrintNewPCs(bool P) { DoPrintNewPCs = P; }
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template <class Callback> size_t CollectFeatures(Callback CB);
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bool UpdateValueProfileMap(ValueBitMap *MaxValueProfileMap) {
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return UseValueProfile && MaxValueProfileMap->MergeFrom(ValueProfileMap);
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}
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void ResetMaps() {
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ValueProfileMap.Reset();
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memset(Counters, 0, sizeof(Counters));
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}
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void UpdateFeatureSet(size_t CurrentElementIdx, size_t CurrentElementSize);
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void PrintFeatureSet();
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void PrintModuleInfo();
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void PrintCoverage();
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void DumpCoverage();
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void AddValueForMemcmp(void *caller_pc, const void *s1, const void *s2,
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size_t n);
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void AddValueForStrcmp(void *caller_pc, const char *s1, const char *s2,
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size_t n);
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bool UsingTracePcGuard() const {return NumModules; }
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static const size_t kTORCSize = 1 << 5;
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TableOfRecentCompares<uint32_t, kTORCSize> TORC4;
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TableOfRecentCompares<uint64_t, kTORCSize> TORC8;
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void PrintNewPCs();
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size_t GetNumPCs() const { return Min(kNumPCs, NumGuards + 1); }
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uintptr_t GetPC(size_t Idx) {
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assert(Idx < GetNumPCs());
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return PCs[Idx];
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}
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private:
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bool UseCounters = false;
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bool UseValueProfile = false;
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bool DoPrintNewPCs = false;
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struct Module {
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uint32_t *Start, *Stop;
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};
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Module Modules[4096];
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size_t NumModules; // linker-initialized.
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size_t NumGuards; // linker-initialized.
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static const size_t kNumCounters = 1 << 14;
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alignas(8) uint8_t Counters[kNumCounters];
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static const size_t kNumPCs = 1 << 24;
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uintptr_t PCs[kNumPCs];
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std::set<uintptr_t> *PrintedPCs;
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ValueBitMap ValueProfileMap;
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};
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template <class Callback>
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size_t TracePC::CollectFeatures(Callback CB) {
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if (!UsingTracePcGuard()) return 0;
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size_t Res = 0;
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const size_t Step = 8;
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assert(reinterpret_cast<uintptr_t>(Counters) % Step == 0);
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size_t N = Min(kNumCounters, NumGuards + 1);
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N = (N + Step - 1) & ~(Step - 1); // Round up.
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for (size_t Idx = 0; Idx < N; Idx += Step) {
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uint64_t Bundle = *reinterpret_cast<uint64_t*>(&Counters[Idx]);
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if (!Bundle) continue;
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for (size_t i = Idx; i < Idx + Step; i++) {
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uint8_t Counter = (Bundle >> ((i - Idx) * 8)) & 0xff;
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if (!Counter) continue;
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Counters[i] = 0;
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unsigned Bit = 0;
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/**/ if (Counter >= 128) Bit = 7;
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else if (Counter >= 32) Bit = 6;
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else if (Counter >= 16) Bit = 5;
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else if (Counter >= 8) Bit = 4;
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else if (Counter >= 4) Bit = 3;
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else if (Counter >= 3) Bit = 2;
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else if (Counter >= 2) Bit = 1;
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size_t Feature = (i * 8 + Bit);
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if (CB(Feature))
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Res++;
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}
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}
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if (UseValueProfile)
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ValueProfileMap.ForEach([&](size_t Idx) {
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if (CB(NumGuards * 8 + Idx))
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Res++;
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});
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return Res;
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}
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extern TracePC TPC;
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} // namespace fuzzer
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#endif // LLVM_FUZZER_TRACE_PC
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