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