1//===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Coverage instrumentation that works with AddressSanitizer
11// and potentially with other Sanitizers.
12//
13// We create a Guard variable with the same linkage
14// as the function and inject this code into the entry block (SCK_Function)
15// or all blocks (SCK_BB):
16// if (Guard < 0) {
17//    __sanitizer_cov(&Guard);
18// }
19// The accesses to Guard are atomic. The rest of the logic is
20// in __sanitizer_cov (it's fine to call it more than once).
21//
22// With SCK_Edge we also split critical edges this effectively
23// instrumenting all edges.
24//
25// This coverage implementation provides very limited data:
26// it only tells if a given function (block) was ever executed. No counters.
27// But for many use cases this is what we need and the added slowdown small.
28//
29//===----------------------------------------------------------------------===//
30
31#include "llvm/Transforms/Instrumentation.h"
32#include "llvm/ADT/ArrayRef.h"
33#include "llvm/ADT/SmallVector.h"
34#include "llvm/Analysis/EHPersonalities.h"
35#include "llvm/IR/CallSite.h"
36#include "llvm/IR/DataLayout.h"
37#include "llvm/IR/DebugInfo.h"
38#include "llvm/IR/Function.h"
39#include "llvm/IR/IRBuilder.h"
40#include "llvm/IR/InlineAsm.h"
41#include "llvm/IR/LLVMContext.h"
42#include "llvm/IR/MDBuilder.h"
43#include "llvm/IR/Module.h"
44#include "llvm/IR/Type.h"
45#include "llvm/Support/CommandLine.h"
46#include "llvm/Support/Debug.h"
47#include "llvm/Support/raw_ostream.h"
48#include "llvm/Transforms/Scalar.h"
49#include "llvm/Transforms/Utils/BasicBlockUtils.h"
50#include "llvm/Transforms/Utils/ModuleUtils.h"
51
52using namespace llvm;
53
54#define DEBUG_TYPE "sancov"
55
56static const char *const kSanCovModuleInitName = "__sanitizer_cov_module_init";
57static const char *const kSanCovName = "__sanitizer_cov";
58static const char *const kSanCovWithCheckName = "__sanitizer_cov_with_check";
59static const char *const kSanCovIndirCallName = "__sanitizer_cov_indir_call16";
60static const char *const kSanCovTraceEnter = "__sanitizer_cov_trace_func_enter";
61static const char *const kSanCovTraceBB = "__sanitizer_cov_trace_basic_block";
62static const char *const kSanCovTraceCmp = "__sanitizer_cov_trace_cmp";
63static const char *const kSanCovTraceSwitch = "__sanitizer_cov_trace_switch";
64static const char *const kSanCovModuleCtorName = "sancov.module_ctor";
65static const uint64_t    kSanCtorAndDtorPriority = 2;
66
67static cl::opt<int> ClCoverageLevel("sanitizer-coverage-level",
68       cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
69                "3: all blocks and critical edges, "
70                "4: above plus indirect calls"),
71       cl::Hidden, cl::init(0));
72
73static cl::opt<unsigned> ClCoverageBlockThreshold(
74    "sanitizer-coverage-block-threshold",
75    cl::desc("Use a callback with a guard check inside it if there are"
76             " more than this number of blocks."),
77    cl::Hidden, cl::init(500));
78
79static cl::opt<bool>
80    ClExperimentalTracing("sanitizer-coverage-experimental-tracing",
81                          cl::desc("Experimental basic-block tracing: insert "
82                                   "callbacks at every basic block"),
83                          cl::Hidden, cl::init(false));
84
85static cl::opt<bool>
86    ClExperimentalCMPTracing("sanitizer-coverage-experimental-trace-compares",
87                             cl::desc("Experimental tracing of CMP and similar "
88                                      "instructions"),
89                             cl::Hidden, cl::init(false));
90
91// Experimental 8-bit counters used as an additional search heuristic during
92// coverage-guided fuzzing.
93// The counters are not thread-friendly:
94//   - contention on these counters may cause significant slowdown;
95//   - the counter updates are racy and the results may be inaccurate.
96// They are also inaccurate due to 8-bit integer overflow.
97static cl::opt<bool> ClUse8bitCounters("sanitizer-coverage-8bit-counters",
98                                       cl::desc("Experimental 8-bit counters"),
99                                       cl::Hidden, cl::init(false));
100
101namespace {
102
103SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
104  SanitizerCoverageOptions Res;
105  switch (LegacyCoverageLevel) {
106  case 0:
107    Res.CoverageType = SanitizerCoverageOptions::SCK_None;
108    break;
109  case 1:
110    Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
111    break;
112  case 2:
113    Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
114    break;
115  case 3:
116    Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
117    break;
118  case 4:
119    Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
120    Res.IndirectCalls = true;
121    break;
122  }
123  return Res;
124}
125
126SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
127  // Sets CoverageType and IndirectCalls.
128  SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
129  Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
130  Options.IndirectCalls |= CLOpts.IndirectCalls;
131  Options.TraceBB |= ClExperimentalTracing;
132  Options.TraceCmp |= ClExperimentalCMPTracing;
133  Options.Use8bitCounters |= ClUse8bitCounters;
134  return Options;
135}
136
137class SanitizerCoverageModule : public ModulePass {
138 public:
139  SanitizerCoverageModule(
140      const SanitizerCoverageOptions &Options = SanitizerCoverageOptions())
141      : ModulePass(ID), Options(OverrideFromCL(Options)) {}
142  bool runOnModule(Module &M) override;
143  bool runOnFunction(Function &F);
144  static char ID;  // Pass identification, replacement for typeid
145  const char *getPassName() const override {
146    return "SanitizerCoverageModule";
147  }
148
149 private:
150  void InjectCoverageForIndirectCalls(Function &F,
151                                      ArrayRef<Instruction *> IndirCalls);
152  void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
153  void InjectTraceForSwitch(Function &F,
154                            ArrayRef<Instruction *> SwitchTraceTargets);
155  bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks);
156  void SetNoSanitizeMetadata(Instruction *I);
157  void InjectCoverageAtBlock(Function &F, BasicBlock &BB, bool UseCalls);
158  unsigned NumberOfInstrumentedBlocks() {
159    return SanCovFunction->getNumUses() +
160           SanCovWithCheckFunction->getNumUses() + SanCovTraceBB->getNumUses() +
161           SanCovTraceEnter->getNumUses();
162  }
163  Function *SanCovFunction;
164  Function *SanCovWithCheckFunction;
165  Function *SanCovIndirCallFunction;
166  Function *SanCovTraceEnter, *SanCovTraceBB;
167  Function *SanCovTraceCmpFunction;
168  Function *SanCovTraceSwitchFunction;
169  InlineAsm *EmptyAsm;
170  Type *IntptrTy, *Int64Ty, *Int64PtrTy;
171  Module *CurModule;
172  LLVMContext *C;
173  const DataLayout *DL;
174
175  GlobalVariable *GuardArray;
176  GlobalVariable *EightBitCounterArray;
177
178  SanitizerCoverageOptions Options;
179};
180
181}  // namespace
182
183bool SanitizerCoverageModule::runOnModule(Module &M) {
184  if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
185    return false;
186  C = &(M.getContext());
187  DL = &M.getDataLayout();
188  CurModule = &M;
189  IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
190  Type *VoidTy = Type::getVoidTy(*C);
191  IRBuilder<> IRB(*C);
192  Type *Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
193  Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
194  Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
195  Int64Ty = IRB.getInt64Ty();
196
197  SanCovFunction = checkSanitizerInterfaceFunction(
198      M.getOrInsertFunction(kSanCovName, VoidTy, Int32PtrTy, nullptr));
199  SanCovWithCheckFunction = checkSanitizerInterfaceFunction(
200      M.getOrInsertFunction(kSanCovWithCheckName, VoidTy, Int32PtrTy, nullptr));
201  SanCovIndirCallFunction =
202      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
203          kSanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr));
204  SanCovTraceCmpFunction =
205      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
206          kSanCovTraceCmp, VoidTy, Int64Ty, Int64Ty, Int64Ty, nullptr));
207  SanCovTraceSwitchFunction =
208      checkSanitizerInterfaceFunction(M.getOrInsertFunction(
209          kSanCovTraceSwitch, VoidTy, Int64Ty, Int64PtrTy, nullptr));
210
211  // We insert an empty inline asm after cov callbacks to avoid callback merge.
212  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
213                            StringRef(""), StringRef(""),
214                            /*hasSideEffects=*/true);
215
216  SanCovTraceEnter = checkSanitizerInterfaceFunction(
217      M.getOrInsertFunction(kSanCovTraceEnter, VoidTy, Int32PtrTy, nullptr));
218  SanCovTraceBB = checkSanitizerInterfaceFunction(
219      M.getOrInsertFunction(kSanCovTraceBB, VoidTy, Int32PtrTy, nullptr));
220
221  // At this point we create a dummy array of guards because we don't
222  // know how many elements we will need.
223  Type *Int32Ty = IRB.getInt32Ty();
224  Type *Int8Ty = IRB.getInt8Ty();
225
226  GuardArray =
227      new GlobalVariable(M, Int32Ty, false, GlobalValue::ExternalLinkage,
228                         nullptr, "__sancov_gen_cov_tmp");
229  if (Options.Use8bitCounters)
230    EightBitCounterArray =
231        new GlobalVariable(M, Int8Ty, false, GlobalVariable::ExternalLinkage,
232                           nullptr, "__sancov_gen_cov_tmp");
233
234  for (auto &F : M)
235    runOnFunction(F);
236
237  auto N = NumberOfInstrumentedBlocks();
238
239  // Now we know how many elements we need. Create an array of guards
240  // with one extra element at the beginning for the size.
241  Type *Int32ArrayNTy = ArrayType::get(Int32Ty, N + 1);
242  GlobalVariable *RealGuardArray = new GlobalVariable(
243      M, Int32ArrayNTy, false, GlobalValue::PrivateLinkage,
244      Constant::getNullValue(Int32ArrayNTy), "__sancov_gen_cov");
245
246
247  // Replace the dummy array with the real one.
248  GuardArray->replaceAllUsesWith(
249      IRB.CreatePointerCast(RealGuardArray, Int32PtrTy));
250  GuardArray->eraseFromParent();
251
252  GlobalVariable *RealEightBitCounterArray;
253  if (Options.Use8bitCounters) {
254    // Make sure the array is 16-aligned.
255    static const int kCounterAlignment = 16;
256    Type *Int8ArrayNTy =
257        ArrayType::get(Int8Ty, RoundUpToAlignment(N, kCounterAlignment));
258    RealEightBitCounterArray = new GlobalVariable(
259        M, Int8ArrayNTy, false, GlobalValue::PrivateLinkage,
260        Constant::getNullValue(Int8ArrayNTy), "__sancov_gen_cov_counter");
261    RealEightBitCounterArray->setAlignment(kCounterAlignment);
262    EightBitCounterArray->replaceAllUsesWith(
263        IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy));
264    EightBitCounterArray->eraseFromParent();
265  }
266
267  // Create variable for module (compilation unit) name
268  Constant *ModNameStrConst =
269      ConstantDataArray::getString(M.getContext(), M.getName(), true);
270  GlobalVariable *ModuleName =
271      new GlobalVariable(M, ModNameStrConst->getType(), true,
272                         GlobalValue::PrivateLinkage, ModNameStrConst);
273
274  Function *CtorFunc;
275  std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
276      M, kSanCovModuleCtorName, kSanCovModuleInitName,
277      {Int32PtrTy, IntptrTy, Int8PtrTy, Int8PtrTy},
278      {IRB.CreatePointerCast(RealGuardArray, Int32PtrTy),
279       ConstantInt::get(IntptrTy, N),
280       Options.Use8bitCounters
281           ? IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy)
282           : Constant::getNullValue(Int8PtrTy),
283       IRB.CreatePointerCast(ModuleName, Int8PtrTy)});
284
285  appendToGlobalCtors(M, CtorFunc, kSanCtorAndDtorPriority);
286
287  return true;
288}
289
290bool SanitizerCoverageModule::runOnFunction(Function &F) {
291  if (F.empty()) return false;
292  if (F.getName().find(".module_ctor") != std::string::npos)
293    return false;  // Should not instrument sanitizer init functions.
294  // Don't instrument functions using SEH for now. Splitting basic blocks like
295  // we do for coverage breaks WinEHPrepare.
296  // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
297  if (F.hasPersonalityFn() &&
298      isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
299    return false;
300  if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
301    SplitAllCriticalEdges(F);
302  SmallVector<Instruction*, 8> IndirCalls;
303  SmallVector<BasicBlock*, 16> AllBlocks;
304  SmallVector<Instruction*, 8> CmpTraceTargets;
305  SmallVector<Instruction*, 8> SwitchTraceTargets;
306  for (auto &BB : F) {
307    AllBlocks.push_back(&BB);
308    for (auto &Inst : BB) {
309      if (Options.IndirectCalls) {
310        CallSite CS(&Inst);
311        if (CS && !CS.getCalledFunction())
312          IndirCalls.push_back(&Inst);
313      }
314      if (Options.TraceCmp) {
315        if (isa<ICmpInst>(&Inst))
316          CmpTraceTargets.push_back(&Inst);
317        if (isa<SwitchInst>(&Inst))
318          SwitchTraceTargets.push_back(&Inst);
319      }
320    }
321  }
322  InjectCoverage(F, AllBlocks);
323  InjectCoverageForIndirectCalls(F, IndirCalls);
324  InjectTraceForCmp(F, CmpTraceTargets);
325  InjectTraceForSwitch(F, SwitchTraceTargets);
326  return true;
327}
328
329bool SanitizerCoverageModule::InjectCoverage(Function &F,
330                                             ArrayRef<BasicBlock *> AllBlocks) {
331  switch (Options.CoverageType) {
332  case SanitizerCoverageOptions::SCK_None:
333    return false;
334  case SanitizerCoverageOptions::SCK_Function:
335    InjectCoverageAtBlock(F, F.getEntryBlock(), false);
336    return true;
337  default: {
338    bool UseCalls = ClCoverageBlockThreshold < AllBlocks.size();
339    for (auto BB : AllBlocks)
340      InjectCoverageAtBlock(F, *BB, UseCalls);
341    return true;
342  }
343  }
344}
345
346// On every indirect call we call a run-time function
347// __sanitizer_cov_indir_call* with two parameters:
348//   - callee address,
349//   - global cache array that contains kCacheSize pointers (zero-initialized).
350//     The cache is used to speed up recording the caller-callee pairs.
351// The address of the caller is passed implicitly via caller PC.
352// kCacheSize is encoded in the name of the run-time function.
353void SanitizerCoverageModule::InjectCoverageForIndirectCalls(
354    Function &F, ArrayRef<Instruction *> IndirCalls) {
355  if (IndirCalls.empty()) return;
356  const int kCacheSize = 16;
357  const int kCacheAlignment = 64;  // Align for better performance.
358  Type *Ty = ArrayType::get(IntptrTy, kCacheSize);
359  for (auto I : IndirCalls) {
360    IRBuilder<> IRB(I);
361    CallSite CS(I);
362    Value *Callee = CS.getCalledValue();
363    if (isa<InlineAsm>(Callee)) continue;
364    GlobalVariable *CalleeCache = new GlobalVariable(
365        *F.getParent(), Ty, false, GlobalValue::PrivateLinkage,
366        Constant::getNullValue(Ty), "__sancov_gen_callee_cache");
367    CalleeCache->setAlignment(kCacheAlignment);
368    IRB.CreateCall(SanCovIndirCallFunction,
369                   {IRB.CreatePointerCast(Callee, IntptrTy),
370                    IRB.CreatePointerCast(CalleeCache, IntptrTy)});
371  }
372}
373
374// For every switch statement we insert a call:
375// __sanitizer_cov_trace_switch(CondValue,
376//      {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
377
378void SanitizerCoverageModule::InjectTraceForSwitch(
379    Function &F, ArrayRef<Instruction *> SwitchTraceTargets) {
380  for (auto I : SwitchTraceTargets) {
381    if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
382      IRBuilder<> IRB(I);
383      SmallVector<Constant *, 16> Initializers;
384      Value *Cond = SI->getCondition();
385      if (Cond->getType()->getScalarSizeInBits() >
386          Int64Ty->getScalarSizeInBits())
387        continue;
388      Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
389      Initializers.push_back(
390          ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
391      if (Cond->getType()->getScalarSizeInBits() <
392          Int64Ty->getScalarSizeInBits())
393        Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
394      for (auto It: SI->cases()) {
395        Constant *C = It.getCaseValue();
396        if (C->getType()->getScalarSizeInBits() <
397            Int64Ty->getScalarSizeInBits())
398          C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
399        Initializers.push_back(C);
400      }
401      ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
402      GlobalVariable *GV = new GlobalVariable(
403          *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
404          ConstantArray::get(ArrayOfInt64Ty, Initializers),
405          "__sancov_gen_cov_switch_values");
406      IRB.CreateCall(SanCovTraceSwitchFunction,
407                     {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
408    }
409  }
410}
411
412
413void SanitizerCoverageModule::InjectTraceForCmp(
414    Function &F, ArrayRef<Instruction *> CmpTraceTargets) {
415  for (auto I : CmpTraceTargets) {
416    if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
417      IRBuilder<> IRB(ICMP);
418      Value *A0 = ICMP->getOperand(0);
419      Value *A1 = ICMP->getOperand(1);
420      if (!A0->getType()->isIntegerTy()) continue;
421      uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
422      // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
423      IRB.CreateCall(
424          SanCovTraceCmpFunction,
425          {ConstantInt::get(Int64Ty, (TypeSize << 32) | ICMP->getPredicate()),
426           IRB.CreateIntCast(A0, Int64Ty, true),
427           IRB.CreateIntCast(A1, Int64Ty, true)});
428    }
429  }
430}
431
432void SanitizerCoverageModule::SetNoSanitizeMetadata(Instruction *I) {
433  I->setMetadata(
434      I->getModule()->getMDKindID("nosanitize"), MDNode::get(*C, None));
435}
436
437void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
438                                                    bool UseCalls) {
439  // Don't insert coverage for unreachable blocks: we will never call
440  // __sanitizer_cov() for them, so counting them in
441  // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
442  // percentage. Also, unreachable instructions frequently have no debug
443  // locations.
444  if (isa<UnreachableInst>(BB.getTerminator()))
445    return;
446  BasicBlock::iterator IP = BB.getFirstInsertionPt();
447
448  bool IsEntryBB = &BB == &F.getEntryBlock();
449  DebugLoc EntryLoc;
450  if (IsEntryBB) {
451    if (auto SP = getDISubprogram(&F))
452      EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
453    // Keep static allocas and llvm.localescape calls in the entry block.  Even
454    // if we aren't splitting the block, it's nice for allocas to be before
455    // calls.
456    IP = PrepareToSplitEntryBlock(BB, IP);
457  } else {
458    EntryLoc = IP->getDebugLoc();
459  }
460
461  IRBuilder<> IRB(&*IP);
462  IRB.SetCurrentDebugLocation(EntryLoc);
463  Value *GuardP = IRB.CreateAdd(
464      IRB.CreatePointerCast(GuardArray, IntptrTy),
465      ConstantInt::get(IntptrTy, (1 + NumberOfInstrumentedBlocks()) * 4));
466  Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
467  GuardP = IRB.CreateIntToPtr(GuardP, Int32PtrTy);
468  if (Options.TraceBB) {
469    IRB.CreateCall(IsEntryBB ? SanCovTraceEnter : SanCovTraceBB, GuardP);
470  } else if (UseCalls) {
471    IRB.CreateCall(SanCovWithCheckFunction, GuardP);
472  } else {
473    LoadInst *Load = IRB.CreateLoad(GuardP);
474    Load->setAtomic(Monotonic);
475    Load->setAlignment(4);
476    SetNoSanitizeMetadata(Load);
477    Value *Cmp = IRB.CreateICmpSGE(Constant::getNullValue(Load->getType()), Load);
478    Instruction *Ins = SplitBlockAndInsertIfThen(
479        Cmp, &*IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
480    IRB.SetInsertPoint(Ins);
481    IRB.SetCurrentDebugLocation(EntryLoc);
482    // __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
483    IRB.CreateCall(SanCovFunction, GuardP);
484    IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
485  }
486
487  if (Options.Use8bitCounters) {
488    IRB.SetInsertPoint(&*IP);
489    Value *P = IRB.CreateAdd(
490        IRB.CreatePointerCast(EightBitCounterArray, IntptrTy),
491        ConstantInt::get(IntptrTy, NumberOfInstrumentedBlocks() - 1));
492    P = IRB.CreateIntToPtr(P, IRB.getInt8PtrTy());
493    LoadInst *LI = IRB.CreateLoad(P);
494    Value *Inc = IRB.CreateAdd(LI, ConstantInt::get(IRB.getInt8Ty(), 1));
495    StoreInst *SI = IRB.CreateStore(Inc, P);
496    SetNoSanitizeMetadata(LI);
497    SetNoSanitizeMetadata(SI);
498  }
499}
500
501char SanitizerCoverageModule::ID = 0;
502INITIALIZE_PASS(SanitizerCoverageModule, "sancov",
503    "SanitizerCoverage: TODO."
504    "ModulePass", false, false)
505ModulePass *llvm::createSanitizerCoverageModulePass(
506    const SanitizerCoverageOptions &Options) {
507  return new SanitizerCoverageModule(Options);
508}
509