1//===- FuzzerTracePC.cpp - PC tracing--------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// Trace PCs.
9// This module implements __sanitizer_cov_trace_pc_guard[_init],
10// the callback required for -fsanitize-coverage=trace-pc-guard instrumentation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "FuzzerTracePC.h"
15#include "FuzzerBuiltins.h"
16#include "FuzzerBuiltinsMsvc.h"
17#include "FuzzerCorpus.h"
18#include "FuzzerDefs.h"
19#include "FuzzerDictionary.h"
20#include "FuzzerExtFunctions.h"
21#include "FuzzerIO.h"
22#include "FuzzerPlatform.h"
23#include "FuzzerUtil.h"
24#include "FuzzerValueBitMap.h"
25#include <set>
26
27// Used by -fsanitize-coverage=stack-depth to track stack depth
28ATTRIBUTES_INTERFACE_TLS_INITIAL_EXEC uintptr_t __sancov_lowest_stack;
29
30namespace fuzzer {
31
32TracePC TPC;
33
34size_t TracePC::GetTotalPCCoverage() {
35  return ObservedPCs.size();
36}
37
38
39void TracePC::HandleInline8bitCountersInit(uint8_t *Start, uint8_t *Stop) {
40  if (Start == Stop) return;
41  if (NumModules &&
42      Modules[NumModules - 1].Start() == Start)
43    return;
44  assert(NumModules <
45         sizeof(Modules) / sizeof(Modules[0]));
46  auto &M = Modules[NumModules++];
47  uint8_t *AlignedStart = RoundUpByPage(Start);
48  uint8_t *AlignedStop  = RoundDownByPage(Stop);
49  size_t NumFullPages = AlignedStop > AlignedStart ?
50                        (AlignedStop - AlignedStart) / PageSize() : 0;
51  bool NeedFirst = Start < AlignedStart || !NumFullPages;
52  bool NeedLast  = Stop > AlignedStop && AlignedStop >= AlignedStart;
53  M.NumRegions = NumFullPages + NeedFirst + NeedLast;;
54  assert(M.NumRegions > 0);
55  M.Regions = new Module::Region[M.NumRegions];
56  assert(M.Regions);
57  size_t R = 0;
58  if (NeedFirst)
59    M.Regions[R++] = {Start, std::min(Stop, AlignedStart), true, false};
60  for (uint8_t *P = AlignedStart; P < AlignedStop; P += PageSize())
61    M.Regions[R++] = {P, P + PageSize(), true, true};
62  if (NeedLast)
63    M.Regions[R++] = {AlignedStop, Stop, true, false};
64  assert(R == M.NumRegions);
65  assert(M.Size() == (size_t)(Stop - Start));
66  assert(M.Stop() == Stop);
67  assert(M.Start() == Start);
68  NumInline8bitCounters += M.Size();
69}
70
71void TracePC::HandlePCsInit(const uintptr_t *Start, const uintptr_t *Stop) {
72  const PCTableEntry *B = reinterpret_cast<const PCTableEntry *>(Start);
73  const PCTableEntry *E = reinterpret_cast<const PCTableEntry *>(Stop);
74  if (NumPCTables && ModulePCTable[NumPCTables - 1].Start == B) return;
75  assert(NumPCTables < sizeof(ModulePCTable) / sizeof(ModulePCTable[0]));
76  ModulePCTable[NumPCTables++] = {B, E};
77  NumPCsInPCTables += E - B;
78}
79
80void TracePC::PrintModuleInfo() {
81  if (NumModules) {
82    Printf("INFO: Loaded %zd modules   (%zd inline 8-bit counters): ",
83           NumModules, NumInline8bitCounters);
84    for (size_t i = 0; i < NumModules; i++)
85      Printf("%zd [%p, %p), ", Modules[i].Size(), Modules[i].Start(),
86             Modules[i].Stop());
87    Printf("\n");
88  }
89  if (NumPCTables) {
90    Printf("INFO: Loaded %zd PC tables (%zd PCs): ", NumPCTables,
91           NumPCsInPCTables);
92    for (size_t i = 0; i < NumPCTables; i++) {
93      Printf("%zd [%p,%p), ", ModulePCTable[i].Stop - ModulePCTable[i].Start,
94             ModulePCTable[i].Start, ModulePCTable[i].Stop);
95    }
96    Printf("\n");
97
98    if (NumInline8bitCounters && NumInline8bitCounters != NumPCsInPCTables) {
99      Printf("ERROR: The size of coverage PC tables does not match the\n"
100             "number of instrumented PCs. This might be a compiler bug,\n"
101             "please contact the libFuzzer developers.\n"
102             "Also check https://bugs.llvm.org/show_bug.cgi?id=34636\n"
103             "for possible workarounds (tl;dr: don't use the old GNU ld)\n");
104      _Exit(1);
105    }
106  }
107  if (size_t NumExtraCounters = ExtraCountersEnd() - ExtraCountersBegin())
108    Printf("INFO: %zd Extra Counters\n", NumExtraCounters);
109}
110
111ATTRIBUTE_NO_SANITIZE_ALL
112void TracePC::HandleCallerCallee(uintptr_t Caller, uintptr_t Callee) {
113  const uintptr_t kBits = 12;
114  const uintptr_t kMask = (1 << kBits) - 1;
115  uintptr_t Idx = (Caller & kMask) | ((Callee & kMask) << kBits);
116  ValueProfileMap.AddValueModPrime(Idx);
117}
118
119/// \return the address of the previous instruction.
120/// Note: the logic is copied from `sanitizer_common/sanitizer_stacktrace.h`
121inline ALWAYS_INLINE uintptr_t GetPreviousInstructionPc(uintptr_t PC) {
122#if defined(__arm__)
123  // T32 (Thumb) branch instructions might be 16 or 32 bit long,
124  // so we return (pc-2) in that case in order to be safe.
125  // For A32 mode we return (pc-4) because all instructions are 32 bit long.
126  return (PC - 3) & (~1);
127#elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__)
128  // PCs are always 4 byte aligned.
129  return PC - 4;
130#elif defined(__sparc__) || defined(__mips__)
131  return PC - 8;
132#else
133  return PC - 1;
134#endif
135}
136
137/// \return the address of the next instruction.
138/// Note: the logic is copied from `sanitizer_common/sanitizer_stacktrace.cpp`
139ALWAYS_INLINE uintptr_t TracePC::GetNextInstructionPc(uintptr_t PC) {
140#if defined(__mips__)
141  return PC + 8;
142#elif defined(__powerpc__) || defined(__sparc__) || defined(__arm__) || \
143    defined(__aarch64__)
144  return PC + 4;
145#else
146  return PC + 1;
147#endif
148}
149
150void TracePC::UpdateObservedPCs() {
151  Vector<uintptr_t> CoveredFuncs;
152  auto ObservePC = [&](const PCTableEntry *TE) {
153    if (ObservedPCs.insert(TE).second && DoPrintNewPCs) {
154      PrintPC("\tNEW_PC: %p %F %L", "\tNEW_PC: %p",
155              GetNextInstructionPc(TE->PC));
156      Printf("\n");
157    }
158  };
159
160  auto Observe = [&](const PCTableEntry *TE) {
161    if (PcIsFuncEntry(TE))
162      if (++ObservedFuncs[TE->PC] == 1 && NumPrintNewFuncs)
163        CoveredFuncs.push_back(TE->PC);
164    ObservePC(TE);
165  };
166
167  if (NumPCsInPCTables) {
168    if (NumInline8bitCounters == NumPCsInPCTables) {
169      for (size_t i = 0; i < NumModules; i++) {
170        auto &M = Modules[i];
171        assert(M.Size() ==
172               (size_t)(ModulePCTable[i].Stop - ModulePCTable[i].Start));
173        for (size_t r = 0; r < M.NumRegions; r++) {
174          auto &R = M.Regions[r];
175          if (!R.Enabled) continue;
176          for (uint8_t *P = R.Start; P < R.Stop; P++)
177            if (*P)
178              Observe(&ModulePCTable[i].Start[M.Idx(P)]);
179        }
180      }
181    }
182  }
183
184  for (size_t i = 0, N = Min(CoveredFuncs.size(), NumPrintNewFuncs); i < N;
185       i++) {
186    Printf("\tNEW_FUNC[%zd/%zd]: ", i + 1, CoveredFuncs.size());
187    PrintPC("%p %F %L", "%p", GetNextInstructionPc(CoveredFuncs[i]));
188    Printf("\n");
189  }
190}
191
192uintptr_t TracePC::PCTableEntryIdx(const PCTableEntry *TE) {
193  size_t TotalTEs = 0;
194  for (size_t i = 0; i < NumPCTables; i++) {
195    auto &M = ModulePCTable[i];
196    if (TE >= M.Start && TE < M.Stop)
197      return TotalTEs + TE - M.Start;
198    TotalTEs += M.Stop - M.Start;
199  }
200  assert(0);
201  return 0;
202}
203
204const TracePC::PCTableEntry *TracePC::PCTableEntryByIdx(uintptr_t Idx) {
205  for (size_t i = 0; i < NumPCTables; i++) {
206    auto &M = ModulePCTable[i];
207    size_t Size = M.Stop - M.Start;
208    if (Idx < Size) return &M.Start[Idx];
209    Idx -= Size;
210  }
211  return nullptr;
212}
213
214static std::string GetModuleName(uintptr_t PC) {
215  char ModulePathRaw[4096] = "";  // What's PATH_MAX in portable C++?
216  void *OffsetRaw = nullptr;
217  if (!EF->__sanitizer_get_module_and_offset_for_pc(
218      reinterpret_cast<void *>(PC), ModulePathRaw,
219      sizeof(ModulePathRaw), &OffsetRaw))
220    return "";
221  return ModulePathRaw;
222}
223
224template<class CallBack>
225void TracePC::IterateCoveredFunctions(CallBack CB) {
226  for (size_t i = 0; i < NumPCTables; i++) {
227    auto &M = ModulePCTable[i];
228    assert(M.Start < M.Stop);
229    auto ModuleName = GetModuleName(M.Start->PC);
230    for (auto NextFE = M.Start; NextFE < M.Stop; ) {
231      auto FE = NextFE;
232      assert(PcIsFuncEntry(FE) && "Not a function entry point");
233      do {
234        NextFE++;
235      } while (NextFE < M.Stop && !(PcIsFuncEntry(NextFE)));
236      CB(FE, NextFE, ObservedFuncs[FE->PC]);
237    }
238  }
239}
240
241void TracePC::SetFocusFunction(const std::string &FuncName) {
242  // This function should be called once.
243  assert(!FocusFunctionCounterPtr);
244  // "auto" is not a valid function name. If this function is called with "auto"
245  // that means the auto focus functionality failed.
246  if (FuncName.empty() || FuncName == "auto")
247    return;
248  for (size_t M = 0; M < NumModules; M++) {
249    auto &PCTE = ModulePCTable[M];
250    size_t N = PCTE.Stop - PCTE.Start;
251    for (size_t I = 0; I < N; I++) {
252      if (!(PcIsFuncEntry(&PCTE.Start[I]))) continue;  // not a function entry.
253      auto Name = DescribePC("%F", GetNextInstructionPc(PCTE.Start[I].PC));
254      if (Name[0] == 'i' && Name[1] == 'n' && Name[2] == ' ')
255        Name = Name.substr(3, std::string::npos);
256      if (FuncName != Name) continue;
257      Printf("INFO: Focus function is set to '%s'\n", Name.c_str());
258      FocusFunctionCounterPtr = Modules[M].Start() + I;
259      return;
260    }
261  }
262
263  Printf("ERROR: Failed to set focus function. Make sure the function name is "
264         "valid (%s) and symbolization is enabled.\n", FuncName.c_str());
265  exit(1);
266}
267
268bool TracePC::ObservedFocusFunction() {
269  return FocusFunctionCounterPtr && *FocusFunctionCounterPtr;
270}
271
272void TracePC::PrintCoverage() {
273  if (!EF->__sanitizer_symbolize_pc ||
274      !EF->__sanitizer_get_module_and_offset_for_pc) {
275    Printf("INFO: __sanitizer_symbolize_pc or "
276           "__sanitizer_get_module_and_offset_for_pc is not available,"
277           " not printing coverage\n");
278    return;
279  }
280  Printf("COVERAGE:\n");
281  auto CoveredFunctionCallback = [&](const PCTableEntry *First,
282                                     const PCTableEntry *Last,
283                                     uintptr_t Counter) {
284    assert(First < Last);
285    auto VisualizePC = GetNextInstructionPc(First->PC);
286    std::string FileStr = DescribePC("%s", VisualizePC);
287    if (!IsInterestingCoverageFile(FileStr))
288      return;
289    std::string FunctionStr = DescribePC("%F", VisualizePC);
290    if (FunctionStr.find("in ") == 0)
291      FunctionStr = FunctionStr.substr(3);
292    std::string LineStr = DescribePC("%l", VisualizePC);
293    size_t NumEdges = Last - First;
294    Vector<uintptr_t> UncoveredPCs;
295    for (auto TE = First; TE < Last; TE++)
296      if (!ObservedPCs.count(TE))
297        UncoveredPCs.push_back(TE->PC);
298    Printf("%sCOVERED_FUNC: hits: %zd", Counter ? "" : "UN", Counter);
299    Printf(" edges: %zd/%zd", NumEdges - UncoveredPCs.size(), NumEdges);
300    Printf(" %s %s:%s\n", FunctionStr.c_str(), FileStr.c_str(),
301           LineStr.c_str());
302    if (Counter)
303      for (auto PC : UncoveredPCs)
304        Printf("  UNCOVERED_PC: %s\n",
305               DescribePC("%s:%l", GetNextInstructionPc(PC)).c_str());
306  };
307
308  IterateCoveredFunctions(CoveredFunctionCallback);
309}
310
311// Value profile.
312// We keep track of various values that affect control flow.
313// These values are inserted into a bit-set-based hash map.
314// Every new bit in the map is treated as a new coverage.
315//
316// For memcmp/strcmp/etc the interesting value is the length of the common
317// prefix of the parameters.
318// For cmp instructions the interesting value is a XOR of the parameters.
319// The interesting value is mixed up with the PC and is then added to the map.
320
321ATTRIBUTE_NO_SANITIZE_ALL
322void TracePC::AddValueForMemcmp(void *caller_pc, const void *s1, const void *s2,
323                                size_t n, bool StopAtZero) {
324  if (!n) return;
325  size_t Len = std::min(n, Word::GetMaxSize());
326  const uint8_t *A1 = reinterpret_cast<const uint8_t *>(s1);
327  const uint8_t *A2 = reinterpret_cast<const uint8_t *>(s2);
328  uint8_t B1[Word::kMaxSize];
329  uint8_t B2[Word::kMaxSize];
330  // Copy the data into locals in this non-msan-instrumented function
331  // to avoid msan complaining further.
332  size_t Hash = 0;  // Compute some simple hash of both strings.
333  for (size_t i = 0; i < Len; i++) {
334    B1[i] = A1[i];
335    B2[i] = A2[i];
336    size_t T = B1[i];
337    Hash ^= (T << 8) | B2[i];
338  }
339  size_t I = 0;
340  uint8_t HammingDistance = 0;
341  for (; I < Len; I++) {
342    if (B1[I] != B2[I] || (StopAtZero && B1[I] == 0)) {
343      HammingDistance = Popcountll(B1[I] ^ B2[I]);
344      break;
345    }
346  }
347  size_t PC = reinterpret_cast<size_t>(caller_pc);
348  size_t Idx = (PC & 4095) | (I << 12);
349  Idx += HammingDistance;
350  ValueProfileMap.AddValue(Idx);
351  TORCW.Insert(Idx ^ Hash, Word(B1, Len), Word(B2, Len));
352}
353
354template <class T>
355ATTRIBUTE_TARGET_POPCNT ALWAYS_INLINE
356ATTRIBUTE_NO_SANITIZE_ALL
357void TracePC::HandleCmp(uintptr_t PC, T Arg1, T Arg2) {
358  uint64_t ArgXor = Arg1 ^ Arg2;
359  if (sizeof(T) == 4)
360      TORC4.Insert(ArgXor, Arg1, Arg2);
361  else if (sizeof(T) == 8)
362      TORC8.Insert(ArgXor, Arg1, Arg2);
363  uint64_t HammingDistance = Popcountll(ArgXor);  // [0,64]
364  uint64_t AbsoluteDistance = (Arg1 == Arg2 ? 0 : Clzll(Arg1 - Arg2) + 1);
365  ValueProfileMap.AddValue(PC * 128 + HammingDistance);
366  ValueProfileMap.AddValue(PC * 128 + 64 + AbsoluteDistance);
367}
368
369static size_t InternalStrnlen(const char *S, size_t MaxLen) {
370  size_t Len = 0;
371  for (; Len < MaxLen && S[Len]; Len++) {}
372  return Len;
373}
374
375// Finds min of (strlen(S1), strlen(S2)).
376// Needed bacause one of these strings may actually be non-zero terminated.
377static size_t InternalStrnlen2(const char *S1, const char *S2) {
378  size_t Len = 0;
379  for (; S1[Len] && S2[Len]; Len++)  {}
380  return Len;
381}
382
383void TracePC::ClearInlineCounters() {
384  IterateCounterRegions([](const Module::Region &R){
385    if (R.Enabled)
386      memset(R.Start, 0, R.Stop - R.Start);
387  });
388}
389
390ATTRIBUTE_NO_SANITIZE_ALL
391void TracePC::RecordInitialStack() {
392  int stack;
393  __sancov_lowest_stack = InitialStack = reinterpret_cast<uintptr_t>(&stack);
394}
395
396uintptr_t TracePC::GetMaxStackOffset() const {
397  return InitialStack - __sancov_lowest_stack;  // Stack grows down
398}
399
400void WarnAboutDeprecatedInstrumentation(const char *flag) {
401  // Use RawPrint because Printf cannot be used on Windows before OutputFile is
402  // initialized.
403  RawPrint(flag);
404  RawPrint(
405      " is no longer supported by libFuzzer.\n"
406      "Please either migrate to a compiler that supports -fsanitize=fuzzer\n"
407      "or use an older version of libFuzzer\n");
408  exit(1);
409}
410
411} // namespace fuzzer
412
413extern "C" {
414ATTRIBUTE_INTERFACE
415ATTRIBUTE_NO_SANITIZE_ALL
416void __sanitizer_cov_trace_pc_guard(uint32_t *Guard) {
417  fuzzer::WarnAboutDeprecatedInstrumentation(
418      "-fsanitize-coverage=trace-pc-guard");
419}
420
421// Best-effort support for -fsanitize-coverage=trace-pc, which is available
422// in both Clang and GCC.
423ATTRIBUTE_INTERFACE
424ATTRIBUTE_NO_SANITIZE_ALL
425void __sanitizer_cov_trace_pc() {
426  fuzzer::WarnAboutDeprecatedInstrumentation("-fsanitize-coverage=trace-pc");
427}
428
429ATTRIBUTE_INTERFACE
430void __sanitizer_cov_trace_pc_guard_init(uint32_t *Start, uint32_t *Stop) {
431  fuzzer::WarnAboutDeprecatedInstrumentation(
432      "-fsanitize-coverage=trace-pc-guard");
433}
434
435ATTRIBUTE_INTERFACE
436void __sanitizer_cov_8bit_counters_init(uint8_t *Start, uint8_t *Stop) {
437  fuzzer::TPC.HandleInline8bitCountersInit(Start, Stop);
438}
439
440ATTRIBUTE_INTERFACE
441void __sanitizer_cov_pcs_init(const uintptr_t *pcs_beg,
442                              const uintptr_t *pcs_end) {
443  fuzzer::TPC.HandlePCsInit(pcs_beg, pcs_end);
444}
445
446ATTRIBUTE_INTERFACE
447ATTRIBUTE_NO_SANITIZE_ALL
448void __sanitizer_cov_trace_pc_indir(uintptr_t Callee) {
449  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
450  fuzzer::TPC.HandleCallerCallee(PC, Callee);
451}
452
453ATTRIBUTE_INTERFACE
454ATTRIBUTE_NO_SANITIZE_ALL
455ATTRIBUTE_TARGET_POPCNT
456void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
457  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
458  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
459}
460
461ATTRIBUTE_INTERFACE
462ATTRIBUTE_NO_SANITIZE_ALL
463ATTRIBUTE_TARGET_POPCNT
464// Now the __sanitizer_cov_trace_const_cmp[1248] callbacks just mimic
465// the behaviour of __sanitizer_cov_trace_cmp[1248] ones. This, however,
466// should be changed later to make full use of instrumentation.
467void __sanitizer_cov_trace_const_cmp8(uint64_t Arg1, uint64_t Arg2) {
468  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
469  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
470}
471
472ATTRIBUTE_INTERFACE
473ATTRIBUTE_NO_SANITIZE_ALL
474ATTRIBUTE_TARGET_POPCNT
475void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
476  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
477  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
478}
479
480ATTRIBUTE_INTERFACE
481ATTRIBUTE_NO_SANITIZE_ALL
482ATTRIBUTE_TARGET_POPCNT
483void __sanitizer_cov_trace_const_cmp4(uint32_t Arg1, uint32_t Arg2) {
484  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
485  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
486}
487
488ATTRIBUTE_INTERFACE
489ATTRIBUTE_NO_SANITIZE_ALL
490ATTRIBUTE_TARGET_POPCNT
491void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
492  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
493  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
494}
495
496ATTRIBUTE_INTERFACE
497ATTRIBUTE_NO_SANITIZE_ALL
498ATTRIBUTE_TARGET_POPCNT
499void __sanitizer_cov_trace_const_cmp2(uint16_t Arg1, uint16_t Arg2) {
500  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
501  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
502}
503
504ATTRIBUTE_INTERFACE
505ATTRIBUTE_NO_SANITIZE_ALL
506ATTRIBUTE_TARGET_POPCNT
507void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
508  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
509  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
510}
511
512ATTRIBUTE_INTERFACE
513ATTRIBUTE_NO_SANITIZE_ALL
514ATTRIBUTE_TARGET_POPCNT
515void __sanitizer_cov_trace_const_cmp1(uint8_t Arg1, uint8_t Arg2) {
516  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
517  fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
518}
519
520ATTRIBUTE_INTERFACE
521ATTRIBUTE_NO_SANITIZE_ALL
522ATTRIBUTE_TARGET_POPCNT
523void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t *Cases) {
524  uint64_t N = Cases[0];
525  uint64_t ValSizeInBits = Cases[1];
526  uint64_t *Vals = Cases + 2;
527  // Skip the most common and the most boring case: all switch values are small.
528  // We may want to skip this at compile-time, but it will make the
529  // instrumentation less general.
530  if (Vals[N - 1]  < 256)
531    return;
532  // Also skip small inputs values, they won't give good signal.
533  if (Val < 256)
534    return;
535  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
536  size_t i;
537  uint64_t Smaller = 0;
538  uint64_t Larger = ~(uint64_t)0;
539  // Find two switch values such that Smaller < Val < Larger.
540  // Use 0 and 0xfff..f as the defaults.
541  for (i = 0; i < N; i++) {
542    if (Val < Vals[i]) {
543      Larger = Vals[i];
544      break;
545    }
546    if (Val > Vals[i]) Smaller = Vals[i];
547  }
548
549  // Apply HandleCmp to {Val,Smaller} and {Val, Larger},
550  // use i as the PC modifier for HandleCmp.
551  if (ValSizeInBits == 16) {
552    fuzzer::TPC.HandleCmp(PC + 2 * i, static_cast<uint16_t>(Val),
553                          (uint16_t)(Smaller));
554    fuzzer::TPC.HandleCmp(PC + 2 * i + 1, static_cast<uint16_t>(Val),
555                          (uint16_t)(Larger));
556  } else if (ValSizeInBits == 32) {
557    fuzzer::TPC.HandleCmp(PC + 2 * i, static_cast<uint32_t>(Val),
558                          (uint32_t)(Smaller));
559    fuzzer::TPC.HandleCmp(PC + 2 * i + 1, static_cast<uint32_t>(Val),
560                          (uint32_t)(Larger));
561  } else {
562    fuzzer::TPC.HandleCmp(PC + 2*i, Val, Smaller);
563    fuzzer::TPC.HandleCmp(PC + 2*i + 1, Val, Larger);
564  }
565}
566
567ATTRIBUTE_INTERFACE
568ATTRIBUTE_NO_SANITIZE_ALL
569ATTRIBUTE_TARGET_POPCNT
570void __sanitizer_cov_trace_div4(uint32_t Val) {
571  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
572  fuzzer::TPC.HandleCmp(PC, Val, (uint32_t)0);
573}
574
575ATTRIBUTE_INTERFACE
576ATTRIBUTE_NO_SANITIZE_ALL
577ATTRIBUTE_TARGET_POPCNT
578void __sanitizer_cov_trace_div8(uint64_t Val) {
579  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
580  fuzzer::TPC.HandleCmp(PC, Val, (uint64_t)0);
581}
582
583ATTRIBUTE_INTERFACE
584ATTRIBUTE_NO_SANITIZE_ALL
585ATTRIBUTE_TARGET_POPCNT
586void __sanitizer_cov_trace_gep(uintptr_t Idx) {
587  uintptr_t PC = reinterpret_cast<uintptr_t>(GET_CALLER_PC());
588  fuzzer::TPC.HandleCmp(PC, Idx, (uintptr_t)0);
589}
590
591ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
592void __sanitizer_weak_hook_memcmp(void *caller_pc, const void *s1,
593                                  const void *s2, size_t n, int result) {
594  if (!fuzzer::RunningUserCallback) return;
595  if (result == 0) return;  // No reason to mutate.
596  if (n <= 1) return;  // Not interesting.
597  fuzzer::TPC.AddValueForMemcmp(caller_pc, s1, s2, n, /*StopAtZero*/false);
598}
599
600ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
601void __sanitizer_weak_hook_strncmp(void *caller_pc, const char *s1,
602                                   const char *s2, size_t n, int result) {
603  if (!fuzzer::RunningUserCallback) return;
604  if (result == 0) return;  // No reason to mutate.
605  size_t Len1 = fuzzer::InternalStrnlen(s1, n);
606  size_t Len2 = fuzzer::InternalStrnlen(s2, n);
607  n = std::min(n, Len1);
608  n = std::min(n, Len2);
609  if (n <= 1) return;  // Not interesting.
610  fuzzer::TPC.AddValueForMemcmp(caller_pc, s1, s2, n, /*StopAtZero*/true);
611}
612
613ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
614void __sanitizer_weak_hook_strcmp(void *caller_pc, const char *s1,
615                                   const char *s2, int result) {
616  if (!fuzzer::RunningUserCallback) return;
617  if (result == 0) return;  // No reason to mutate.
618  size_t N = fuzzer::InternalStrnlen2(s1, s2);
619  if (N <= 1) return;  // Not interesting.
620  fuzzer::TPC.AddValueForMemcmp(caller_pc, s1, s2, N, /*StopAtZero*/true);
621}
622
623ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
624void __sanitizer_weak_hook_strncasecmp(void *called_pc, const char *s1,
625                                       const char *s2, size_t n, int result) {
626  if (!fuzzer::RunningUserCallback) return;
627  return __sanitizer_weak_hook_strncmp(called_pc, s1, s2, n, result);
628}
629
630ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
631void __sanitizer_weak_hook_strcasecmp(void *called_pc, const char *s1,
632                                      const char *s2, int result) {
633  if (!fuzzer::RunningUserCallback) return;
634  return __sanitizer_weak_hook_strcmp(called_pc, s1, s2, result);
635}
636
637ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
638void __sanitizer_weak_hook_strstr(void *called_pc, const char *s1,
639                                  const char *s2, char *result) {
640  if (!fuzzer::RunningUserCallback) return;
641  fuzzer::TPC.MMT.Add(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
642}
643
644ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
645void __sanitizer_weak_hook_strcasestr(void *called_pc, const char *s1,
646                                      const char *s2, char *result) {
647  if (!fuzzer::RunningUserCallback) return;
648  fuzzer::TPC.MMT.Add(reinterpret_cast<const uint8_t *>(s2), strlen(s2));
649}
650
651ATTRIBUTE_INTERFACE ATTRIBUTE_NO_SANITIZE_MEMORY
652void __sanitizer_weak_hook_memmem(void *called_pc, const void *s1, size_t len1,
653                                  const void *s2, size_t len2, void *result) {
654  if (!fuzzer::RunningUserCallback) return;
655  fuzzer::TPC.MMT.Add(reinterpret_cast<const uint8_t *>(s2), len2);
656}
657}  // extern "C"
658