1 //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// 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 // 9 // Coverage instrumentation done on LLVM IR level, works with Sanitizers. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h" 14 #include "llvm/ADT/ArrayRef.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/Analysis/EHPersonalities.h" 17 #include "llvm/Analysis/PostDominators.h" 18 #include "llvm/IR/CFG.h" 19 #include "llvm/IR/Constant.h" 20 #include "llvm/IR/DataLayout.h" 21 #include "llvm/IR/DebugInfo.h" 22 #include "llvm/IR/Dominators.h" 23 #include "llvm/IR/Function.h" 24 #include "llvm/IR/GlobalVariable.h" 25 #include "llvm/IR/IRBuilder.h" 26 #include "llvm/IR/InlineAsm.h" 27 #include "llvm/IR/IntrinsicInst.h" 28 #include "llvm/IR/Intrinsics.h" 29 #include "llvm/IR/LLVMContext.h" 30 #include "llvm/IR/MDBuilder.h" 31 #include "llvm/IR/Mangler.h" 32 #include "llvm/IR/Module.h" 33 #include "llvm/IR/Type.h" 34 #include "llvm/InitializePasses.h" 35 #include "llvm/Support/CommandLine.h" 36 #include "llvm/Support/Debug.h" 37 #include "llvm/Support/SpecialCaseList.h" 38 #include "llvm/Support/VirtualFileSystem.h" 39 #include "llvm/Support/raw_ostream.h" 40 #include "llvm/Transforms/Instrumentation.h" 41 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 42 #include "llvm/Transforms/Utils/ModuleUtils.h" 43 44 using namespace llvm; 45 46 #define DEBUG_TYPE "sancov" 47 48 static const char *const SanCovTracePCIndirName = 49 "__sanitizer_cov_trace_pc_indir"; 50 static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc"; 51 static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1"; 52 static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2"; 53 static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4"; 54 static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8"; 55 static const char *const SanCovTraceConstCmp1 = 56 "__sanitizer_cov_trace_const_cmp1"; 57 static const char *const SanCovTraceConstCmp2 = 58 "__sanitizer_cov_trace_const_cmp2"; 59 static const char *const SanCovTraceConstCmp4 = 60 "__sanitizer_cov_trace_const_cmp4"; 61 static const char *const SanCovTraceConstCmp8 = 62 "__sanitizer_cov_trace_const_cmp8"; 63 static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4"; 64 static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8"; 65 static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep"; 66 static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch"; 67 static const char *const SanCovModuleCtorTracePcGuardName = 68 "sancov.module_ctor_trace_pc_guard"; 69 static const char *const SanCovModuleCtor8bitCountersName = 70 "sancov.module_ctor_8bit_counters"; 71 static const char *const SanCovModuleCtorBoolFlagName = 72 "sancov.module_ctor_bool_flag"; 73 static const uint64_t SanCtorAndDtorPriority = 2; 74 75 static const char *const SanCovTracePCGuardName = 76 "__sanitizer_cov_trace_pc_guard"; 77 static const char *const SanCovTracePCGuardInitName = 78 "__sanitizer_cov_trace_pc_guard_init"; 79 static const char *const SanCov8bitCountersInitName = 80 "__sanitizer_cov_8bit_counters_init"; 81 static const char *const SanCovBoolFlagInitName = 82 "__sanitizer_cov_bool_flag_init"; 83 static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init"; 84 85 static const char *const SanCovGuardsSectionName = "sancov_guards"; 86 static const char *const SanCovCountersSectionName = "sancov_cntrs"; 87 static const char *const SanCovBoolFlagSectionName = "sancov_bools"; 88 static const char *const SanCovPCsSectionName = "sancov_pcs"; 89 90 static const char *const SanCovLowestStackName = "__sancov_lowest_stack"; 91 92 static cl::opt<int> ClCoverageLevel( 93 "sanitizer-coverage-level", 94 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 95 "3: all blocks and critical edges"), 96 cl::Hidden, cl::init(0)); 97 98 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 99 cl::desc("Experimental pc tracing"), cl::Hidden, 100 cl::init(false)); 101 102 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 103 cl::desc("pc tracing with a guard"), 104 cl::Hidden, cl::init(false)); 105 106 // If true, we create a global variable that contains PCs of all instrumented 107 // BBs, put this global into a named section, and pass this section's bounds 108 // to __sanitizer_cov_pcs_init. 109 // This way the coverage instrumentation does not need to acquire the PCs 110 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 111 // inline-bool-flag. 112 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 113 cl::desc("create a static PC table"), 114 cl::Hidden, cl::init(false)); 115 116 static cl::opt<bool> 117 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 118 cl::desc("increments 8-bit counter for every edge"), 119 cl::Hidden, cl::init(false)); 120 121 static cl::opt<bool> 122 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 123 cl::desc("sets a boolean flag for every edge"), cl::Hidden, 124 cl::init(false)); 125 126 static cl::opt<bool> 127 ClCMPTracing("sanitizer-coverage-trace-compares", 128 cl::desc("Tracing of CMP and similar instructions"), 129 cl::Hidden, cl::init(false)); 130 131 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 132 cl::desc("Tracing of DIV instructions"), 133 cl::Hidden, cl::init(false)); 134 135 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 136 cl::desc("Tracing of GEP instructions"), 137 cl::Hidden, cl::init(false)); 138 139 static cl::opt<bool> 140 ClPruneBlocks("sanitizer-coverage-prune-blocks", 141 cl::desc("Reduce the number of instrumented blocks"), 142 cl::Hidden, cl::init(true)); 143 144 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 145 cl::desc("max stack depth tracing"), 146 cl::Hidden, cl::init(false)); 147 148 namespace { 149 150 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 151 SanitizerCoverageOptions Res; 152 switch (LegacyCoverageLevel) { 153 case 0: 154 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 155 break; 156 case 1: 157 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 158 break; 159 case 2: 160 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 161 break; 162 case 3: 163 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 164 break; 165 case 4: 166 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 167 Res.IndirectCalls = true; 168 break; 169 } 170 return Res; 171 } 172 173 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 174 // Sets CoverageType and IndirectCalls. 175 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 176 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 177 Options.IndirectCalls |= CLOpts.IndirectCalls; 178 Options.TraceCmp |= ClCMPTracing; 179 Options.TraceDiv |= ClDIVTracing; 180 Options.TraceGep |= ClGEPTracing; 181 Options.TracePC |= ClTracePC; 182 Options.TracePCGuard |= ClTracePCGuard; 183 Options.Inline8bitCounters |= ClInline8bitCounters; 184 Options.InlineBoolFlag |= ClInlineBoolFlag; 185 Options.PCTable |= ClCreatePCTable; 186 Options.NoPrune |= !ClPruneBlocks; 187 Options.StackDepth |= ClStackDepth; 188 if (!Options.TracePCGuard && !Options.TracePC && 189 !Options.Inline8bitCounters && !Options.StackDepth && 190 !Options.InlineBoolFlag) 191 Options.TracePCGuard = true; // TracePCGuard is default. 192 return Options; 193 } 194 195 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>; 196 using PostDomTreeCallback = 197 function_ref<const PostDominatorTree *(Function &F)>; 198 199 class ModuleSanitizerCoverage { 200 public: 201 ModuleSanitizerCoverage( 202 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 203 const SpecialCaseList *Allowlist = nullptr, 204 const SpecialCaseList *Blocklist = nullptr) 205 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 206 Blocklist(Blocklist) {} 207 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 208 PostDomTreeCallback PDTCallback); 209 210 private: 211 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 212 PostDomTreeCallback PDTCallback); 213 void InjectCoverageForIndirectCalls(Function &F, 214 ArrayRef<Instruction *> IndirCalls); 215 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 216 void InjectTraceForDiv(Function &F, 217 ArrayRef<BinaryOperator *> DivTraceTargets); 218 void InjectTraceForGep(Function &F, 219 ArrayRef<GetElementPtrInst *> GepTraceTargets); 220 void InjectTraceForSwitch(Function &F, 221 ArrayRef<Instruction *> SwitchTraceTargets); 222 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 223 bool IsLeafFunc = true); 224 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 225 Function &F, Type *Ty, 226 const char *Section); 227 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 228 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 229 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 230 bool IsLeafFunc = true); 231 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 232 const char *InitFunctionName, Type *Ty, 233 const char *Section); 234 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 235 Type *Ty); 236 237 void SetNoSanitizeMetadata(Instruction *I) { 238 I->setMetadata(I->getModule()->getMDKindID("nosanitize"), 239 MDNode::get(*C, None)); 240 } 241 242 std::string getSectionName(const std::string &Section) const; 243 std::string getSectionStart(const std::string &Section) const; 244 std::string getSectionEnd(const std::string &Section) const; 245 FunctionCallee SanCovTracePCIndir; 246 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 247 FunctionCallee SanCovTraceCmpFunction[4]; 248 FunctionCallee SanCovTraceConstCmpFunction[4]; 249 FunctionCallee SanCovTraceDivFunction[2]; 250 FunctionCallee SanCovTraceGepFunction; 251 FunctionCallee SanCovTraceSwitchFunction; 252 GlobalVariable *SanCovLowestStack; 253 Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy, 254 *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, *Int1PtrTy; 255 Module *CurModule; 256 std::string CurModuleUniqueId; 257 Triple TargetTriple; 258 LLVMContext *C; 259 const DataLayout *DL; 260 261 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 262 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 263 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 264 GlobalVariable *FunctionPCsArray; // for pc-table. 265 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 266 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 267 268 SanitizerCoverageOptions Options; 269 270 const SpecialCaseList *Allowlist; 271 const SpecialCaseList *Blocklist; 272 }; 273 274 class ModuleSanitizerCoverageLegacyPass : public ModulePass { 275 public: 276 ModuleSanitizerCoverageLegacyPass( 277 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 278 const std::vector<std::string> &AllowlistFiles = 279 std::vector<std::string>(), 280 const std::vector<std::string> &BlocklistFiles = 281 std::vector<std::string>()) 282 : ModulePass(ID), Options(Options) { 283 if (AllowlistFiles.size() > 0) 284 Allowlist = SpecialCaseList::createOrDie(AllowlistFiles, 285 *vfs::getRealFileSystem()); 286 if (BlocklistFiles.size() > 0) 287 Blocklist = SpecialCaseList::createOrDie(BlocklistFiles, 288 *vfs::getRealFileSystem()); 289 initializeModuleSanitizerCoverageLegacyPassPass( 290 *PassRegistry::getPassRegistry()); 291 } 292 bool runOnModule(Module &M) override { 293 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 294 Blocklist.get()); 295 auto DTCallback = [this](Function &F) -> const DominatorTree * { 296 return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); 297 }; 298 auto PDTCallback = [this](Function &F) -> const PostDominatorTree * { 299 return &this->getAnalysis<PostDominatorTreeWrapperPass>(F) 300 .getPostDomTree(); 301 }; 302 return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback); 303 } 304 305 static char ID; // Pass identification, replacement for typeid 306 StringRef getPassName() const override { return "ModuleSanitizerCoverage"; } 307 308 void getAnalysisUsage(AnalysisUsage &AU) const override { 309 AU.addRequired<DominatorTreeWrapperPass>(); 310 AU.addRequired<PostDominatorTreeWrapperPass>(); 311 } 312 313 private: 314 SanitizerCoverageOptions Options; 315 316 std::unique_ptr<SpecialCaseList> Allowlist; 317 std::unique_ptr<SpecialCaseList> Blocklist; 318 }; 319 320 } // namespace 321 322 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M, 323 ModuleAnalysisManager &MAM) { 324 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 325 Blocklist.get()); 326 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 327 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * { 328 return &FAM.getResult<DominatorTreeAnalysis>(F); 329 }; 330 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * { 331 return &FAM.getResult<PostDominatorTreeAnalysis>(F); 332 }; 333 if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 334 return PreservedAnalyses::none(); 335 return PreservedAnalyses::all(); 336 } 337 338 std::pair<Value *, Value *> 339 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 340 Type *Ty) { 341 GlobalVariable *SecStart = 342 new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr, 343 getSectionStart(Section)); 344 SecStart->setVisibility(GlobalValue::HiddenVisibility); 345 GlobalVariable *SecEnd = 346 new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, 347 nullptr, getSectionEnd(Section)); 348 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 349 IRBuilder<> IRB(M.getContext()); 350 Value *SecEndPtr = IRB.CreatePointerCast(SecEnd, Ty); 351 if (!TargetTriple.isOSBinFormatCOFF()) 352 return std::make_pair(IRB.CreatePointerCast(SecStart, Ty), SecEndPtr); 353 354 // Account for the fact that on windows-msvc __start_* symbols actually 355 // point to a uint64_t before the start of the array. 356 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); 357 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, 358 ConstantInt::get(IntptrTy, sizeof(uint64_t))); 359 return std::make_pair(IRB.CreatePointerCast(GEP, Ty), SecEndPtr); 360 } 361 362 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 363 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 364 const char *Section) { 365 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 366 auto SecStart = SecStartEnd.first; 367 auto SecEnd = SecStartEnd.second; 368 Function *CtorFunc; 369 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 370 M, CtorName, InitFunctionName, {Ty, Ty}, {SecStart, SecEnd}); 371 assert(CtorFunc->getName() == CtorName); 372 373 if (TargetTriple.supportsCOMDAT()) { 374 // Use comdat to dedup CtorFunc. 375 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 376 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 377 } else { 378 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 379 } 380 381 if (TargetTriple.isOSBinFormatCOFF()) { 382 // In COFF files, if the contructors are set as COMDAT (they are because 383 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 384 // functions and data) is used, the constructors get stripped. To prevent 385 // this, give the constructors weak ODR linkage and ensure the linker knows 386 // to include the sancov constructor. This way the linker can deduplicate 387 // the constructors but always leave one copy. 388 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 389 appendToUsed(M, CtorFunc); 390 } 391 return CtorFunc; 392 } 393 394 bool ModuleSanitizerCoverage::instrumentModule( 395 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 396 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 397 return false; 398 if (Allowlist && 399 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 400 return false; 401 if (Blocklist && 402 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 403 return false; 404 C = &(M.getContext()); 405 DL = &M.getDataLayout(); 406 CurModule = &M; 407 CurModuleUniqueId = getUniqueModuleId(CurModule); 408 TargetTriple = Triple(M.getTargetTriple()); 409 FunctionGuardArray = nullptr; 410 Function8bitCounterArray = nullptr; 411 FunctionBoolArray = nullptr; 412 FunctionPCsArray = nullptr; 413 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 414 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 415 Type *VoidTy = Type::getVoidTy(*C); 416 IRBuilder<> IRB(*C); 417 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 418 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 419 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 420 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty()); 421 Int64Ty = IRB.getInt64Ty(); 422 Int32Ty = IRB.getInt32Ty(); 423 Int16Ty = IRB.getInt16Ty(); 424 Int8Ty = IRB.getInt8Ty(); 425 Int1Ty = IRB.getInt1Ty(); 426 427 SanCovTracePCIndir = 428 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 429 // Make sure smaller parameters are zero-extended to i64 as required by the 430 // x86_64 ABI. 431 AttributeList SanCovTraceCmpZeroExtAL; 432 if (TargetTriple.getArch() == Triple::x86_64) { 433 SanCovTraceCmpZeroExtAL = 434 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 435 SanCovTraceCmpZeroExtAL = 436 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 437 } 438 439 SanCovTraceCmpFunction[0] = 440 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 441 IRB.getInt8Ty(), IRB.getInt8Ty()); 442 SanCovTraceCmpFunction[1] = 443 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 444 IRB.getInt16Ty(), IRB.getInt16Ty()); 445 SanCovTraceCmpFunction[2] = 446 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 447 IRB.getInt32Ty(), IRB.getInt32Ty()); 448 SanCovTraceCmpFunction[3] = 449 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 450 451 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 452 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 453 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 454 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 455 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 456 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 457 SanCovTraceConstCmpFunction[3] = 458 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 459 460 { 461 AttributeList AL; 462 if (TargetTriple.getArch() == Triple::x86_64) 463 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 464 SanCovTraceDivFunction[0] = 465 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 466 } 467 SanCovTraceDivFunction[1] = 468 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 469 SanCovTraceGepFunction = 470 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 471 SanCovTraceSwitchFunction = 472 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); 473 474 Constant *SanCovLowestStackConstant = 475 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 476 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 477 if (!SanCovLowestStack) { 478 C->emitError(StringRef("'") + SanCovLowestStackName + 479 "' should not be declared by the user"); 480 return true; 481 } 482 SanCovLowestStack->setThreadLocalMode( 483 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 484 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 485 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 486 487 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 488 SanCovTracePCGuard = 489 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); 490 491 for (auto &F : M) 492 instrumentFunction(F, DTCallback, PDTCallback); 493 494 Function *Ctor = nullptr; 495 496 if (FunctionGuardArray) 497 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 498 SanCovTracePCGuardInitName, Int32PtrTy, 499 SanCovGuardsSectionName); 500 if (Function8bitCounterArray) 501 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 502 SanCov8bitCountersInitName, Int8PtrTy, 503 SanCovCountersSectionName); 504 if (FunctionBoolArray) { 505 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 506 SanCovBoolFlagInitName, Int1PtrTy, 507 SanCovBoolFlagSectionName); 508 } 509 if (Ctor && Options.PCTable) { 510 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy); 511 FunctionCallee InitFunction = declareSanitizerInitFunction( 512 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 513 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 514 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 515 } 516 // We don't reference these arrays directly in any of our runtime functions, 517 // so we need to prevent them from being dead stripped. 518 if (TargetTriple.isOSBinFormatMachO()) 519 appendToUsed(M, GlobalsToAppendToUsed); 520 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 521 return true; 522 } 523 524 // True if block has successors and it dominates all of them. 525 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 526 if (succ_begin(BB) == succ_end(BB)) 527 return false; 528 529 for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) { 530 if (!DT->dominates(BB, SUCC)) 531 return false; 532 } 533 534 return true; 535 } 536 537 // True if block has predecessors and it postdominates all of them. 538 static bool isFullPostDominator(const BasicBlock *BB, 539 const PostDominatorTree *PDT) { 540 if (pred_begin(BB) == pred_end(BB)) 541 return false; 542 543 for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) { 544 if (!PDT->dominates(BB, PRED)) 545 return false; 546 } 547 548 return true; 549 } 550 551 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 552 const DominatorTree *DT, 553 const PostDominatorTree *PDT, 554 const SanitizerCoverageOptions &Options) { 555 // Don't insert coverage for blocks containing nothing but unreachable: we 556 // will never call __sanitizer_cov() for them, so counting them in 557 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 558 // percentage. Also, unreachable instructions frequently have no debug 559 // locations. 560 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 561 return false; 562 563 // Don't insert coverage into blocks without a valid insertion point 564 // (catchswitch blocks). 565 if (BB->getFirstInsertionPt() == BB->end()) 566 return false; 567 568 if (Options.NoPrune || &F.getEntryBlock() == BB) 569 return true; 570 571 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 572 &F.getEntryBlock() != BB) 573 return false; 574 575 // Do not instrument full dominators, or full post-dominators with multiple 576 // predecessors. 577 return !isFullDominator(BB, DT) 578 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 579 } 580 581 582 // Returns true iff From->To is a backedge. 583 // A twist here is that we treat From->To as a backedge if 584 // * To dominates From or 585 // * To->UniqueSuccessor dominates From 586 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 587 const DominatorTree *DT) { 588 if (DT->dominates(To, From)) 589 return true; 590 if (auto Next = To->getUniqueSuccessor()) 591 if (DT->dominates(Next, From)) 592 return true; 593 return false; 594 } 595 596 // Prunes uninteresting Cmp instrumentation: 597 // * CMP instructions that feed into loop backedge branch. 598 // 599 // Note that Cmp pruning is controlled by the same flag as the 600 // BB pruning. 601 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, 602 const SanitizerCoverageOptions &Options) { 603 if (!Options.NoPrune) 604 if (CMP->hasOneUse()) 605 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 606 for (BasicBlock *B : BR->successors()) 607 if (IsBackEdge(BR->getParent(), B, DT)) 608 return false; 609 return true; 610 } 611 612 void ModuleSanitizerCoverage::instrumentFunction( 613 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 614 if (F.empty()) 615 return; 616 if (F.getName().find(".module_ctor") != std::string::npos) 617 return; // Should not instrument sanitizer init functions. 618 if (F.getName().startswith("__sanitizer_")) 619 return; // Don't instrument __sanitizer_* callbacks. 620 // Don't touch available_externally functions, their actual body is elewhere. 621 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 622 return; 623 // Don't instrument MSVC CRT configuration helpers. They may run before normal 624 // initialization. 625 if (F.getName() == "__local_stdio_printf_options" || 626 F.getName() == "__local_stdio_scanf_options") 627 return; 628 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 629 return; 630 // Don't instrument functions using SEH for now. Splitting basic blocks like 631 // we do for coverage breaks WinEHPrepare. 632 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 633 if (F.hasPersonalityFn() && 634 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 635 return; 636 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 637 return; 638 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 639 return; 640 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 641 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 642 SmallVector<Instruction *, 8> IndirCalls; 643 SmallVector<BasicBlock *, 16> BlocksToInstrument; 644 SmallVector<Instruction *, 8> CmpTraceTargets; 645 SmallVector<Instruction *, 8> SwitchTraceTargets; 646 SmallVector<BinaryOperator *, 8> DivTraceTargets; 647 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 648 649 const DominatorTree *DT = DTCallback(F); 650 const PostDominatorTree *PDT = PDTCallback(F); 651 bool IsLeafFunc = true; 652 653 for (auto &BB : F) { 654 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 655 BlocksToInstrument.push_back(&BB); 656 for (auto &Inst : BB) { 657 if (Options.IndirectCalls) { 658 CallBase *CB = dyn_cast<CallBase>(&Inst); 659 if (CB && !CB->getCalledFunction()) 660 IndirCalls.push_back(&Inst); 661 } 662 if (Options.TraceCmp) { 663 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 664 if (IsInterestingCmp(CMP, DT, Options)) 665 CmpTraceTargets.push_back(&Inst); 666 if (isa<SwitchInst>(&Inst)) 667 SwitchTraceTargets.push_back(&Inst); 668 } 669 if (Options.TraceDiv) 670 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 671 if (BO->getOpcode() == Instruction::SDiv || 672 BO->getOpcode() == Instruction::UDiv) 673 DivTraceTargets.push_back(BO); 674 if (Options.TraceGep) 675 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 676 GepTraceTargets.push_back(GEP); 677 if (Options.StackDepth) 678 if (isa<InvokeInst>(Inst) || 679 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 680 IsLeafFunc = false; 681 } 682 } 683 684 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 685 InjectCoverageForIndirectCalls(F, IndirCalls); 686 InjectTraceForCmp(F, CmpTraceTargets); 687 InjectTraceForSwitch(F, SwitchTraceTargets); 688 InjectTraceForDiv(F, DivTraceTargets); 689 InjectTraceForGep(F, GepTraceTargets); 690 } 691 692 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 693 size_t NumElements, Function &F, Type *Ty, const char *Section) { 694 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 695 auto Array = new GlobalVariable( 696 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 697 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 698 699 if (TargetTriple.supportsCOMDAT() && !F.isInterposable()) 700 if (auto Comdat = 701 GetOrCreateFunctionComdat(F, TargetTriple, CurModuleUniqueId)) 702 Array->setComdat(Comdat); 703 Array->setSection(getSectionName(Section)); 704 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize())); 705 GlobalsToAppendToUsed.push_back(Array); 706 GlobalsToAppendToCompilerUsed.push_back(Array); 707 MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F)); 708 Array->addMetadata(LLVMContext::MD_associated, *MD); 709 710 return Array; 711 } 712 713 GlobalVariable * 714 ModuleSanitizerCoverage::CreatePCArray(Function &F, 715 ArrayRef<BasicBlock *> AllBlocks) { 716 size_t N = AllBlocks.size(); 717 assert(N); 718 SmallVector<Constant *, 32> PCs; 719 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 720 for (size_t i = 0; i < N; i++) { 721 if (&F.getEntryBlock() == AllBlocks[i]) { 722 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 723 PCs.push_back((Constant *)IRB.CreateIntToPtr( 724 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 725 } else { 726 PCs.push_back((Constant *)IRB.CreatePointerCast( 727 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 728 PCs.push_back((Constant *)IRB.CreateIntToPtr( 729 ConstantInt::get(IntptrTy, 0), IntptrPtrTy)); 730 } 731 } 732 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 733 SanCovPCsSectionName); 734 PCArray->setInitializer( 735 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 736 PCArray->setConstant(true); 737 738 return PCArray; 739 } 740 741 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 742 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 743 if (Options.TracePCGuard) 744 FunctionGuardArray = CreateFunctionLocalArrayInSection( 745 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 746 747 if (Options.Inline8bitCounters) 748 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 749 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 750 if (Options.InlineBoolFlag) 751 FunctionBoolArray = CreateFunctionLocalArrayInSection( 752 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 753 754 if (Options.PCTable) 755 FunctionPCsArray = CreatePCArray(F, AllBlocks); 756 } 757 758 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 759 ArrayRef<BasicBlock *> AllBlocks, 760 bool IsLeafFunc) { 761 if (AllBlocks.empty()) return false; 762 CreateFunctionLocalArrays(F, AllBlocks); 763 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 764 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 765 return true; 766 } 767 768 // On every indirect call we call a run-time function 769 // __sanitizer_cov_indir_call* with two parameters: 770 // - callee address, 771 // - global cache array that contains CacheSize pointers (zero-initialized). 772 // The cache is used to speed up recording the caller-callee pairs. 773 // The address of the caller is passed implicitly via caller PC. 774 // CacheSize is encoded in the name of the run-time function. 775 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 776 Function &F, ArrayRef<Instruction *> IndirCalls) { 777 if (IndirCalls.empty()) 778 return; 779 assert(Options.TracePC || Options.TracePCGuard || 780 Options.Inline8bitCounters || Options.InlineBoolFlag); 781 for (auto I : IndirCalls) { 782 IRBuilder<> IRB(I); 783 CallBase &CB = cast<CallBase>(*I); 784 Value *Callee = CB.getCalledOperand(); 785 if (isa<InlineAsm>(Callee)) 786 continue; 787 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 788 } 789 } 790 791 // For every switch statement we insert a call: 792 // __sanitizer_cov_trace_switch(CondValue, 793 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 794 795 void ModuleSanitizerCoverage::InjectTraceForSwitch( 796 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 797 for (auto I : SwitchTraceTargets) { 798 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 799 IRBuilder<> IRB(I); 800 SmallVector<Constant *, 16> Initializers; 801 Value *Cond = SI->getCondition(); 802 if (Cond->getType()->getScalarSizeInBits() > 803 Int64Ty->getScalarSizeInBits()) 804 continue; 805 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 806 Initializers.push_back( 807 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 808 if (Cond->getType()->getScalarSizeInBits() < 809 Int64Ty->getScalarSizeInBits()) 810 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 811 for (auto It : SI->cases()) { 812 Constant *C = It.getCaseValue(); 813 if (C->getType()->getScalarSizeInBits() < 814 Int64Ty->getScalarSizeInBits()) 815 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 816 Initializers.push_back(C); 817 } 818 llvm::sort(Initializers.begin() + 2, Initializers.end(), 819 [](const Constant *A, const Constant *B) { 820 return cast<ConstantInt>(A)->getLimitedValue() < 821 cast<ConstantInt>(B)->getLimitedValue(); 822 }); 823 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 824 GlobalVariable *GV = new GlobalVariable( 825 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 826 ConstantArray::get(ArrayOfInt64Ty, Initializers), 827 "__sancov_gen_cov_switch_values"); 828 IRB.CreateCall(SanCovTraceSwitchFunction, 829 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 830 } 831 } 832 } 833 834 void ModuleSanitizerCoverage::InjectTraceForDiv( 835 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 836 for (auto BO : DivTraceTargets) { 837 IRBuilder<> IRB(BO); 838 Value *A1 = BO->getOperand(1); 839 if (isa<ConstantInt>(A1)) continue; 840 if (!A1->getType()->isIntegerTy()) 841 continue; 842 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 843 int CallbackIdx = TypeSize == 32 ? 0 : 844 TypeSize == 64 ? 1 : -1; 845 if (CallbackIdx < 0) continue; 846 auto Ty = Type::getIntNTy(*C, TypeSize); 847 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 848 {IRB.CreateIntCast(A1, Ty, true)}); 849 } 850 } 851 852 void ModuleSanitizerCoverage::InjectTraceForGep( 853 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 854 for (auto GEP : GepTraceTargets) { 855 IRBuilder<> IRB(GEP); 856 for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I) 857 if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy()) 858 IRB.CreateCall(SanCovTraceGepFunction, 859 {IRB.CreateIntCast(*I, IntptrTy, true)}); 860 } 861 } 862 863 void ModuleSanitizerCoverage::InjectTraceForCmp( 864 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 865 for (auto I : CmpTraceTargets) { 866 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 867 IRBuilder<> IRB(ICMP); 868 Value *A0 = ICMP->getOperand(0); 869 Value *A1 = ICMP->getOperand(1); 870 if (!A0->getType()->isIntegerTy()) 871 continue; 872 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 873 int CallbackIdx = TypeSize == 8 ? 0 : 874 TypeSize == 16 ? 1 : 875 TypeSize == 32 ? 2 : 876 TypeSize == 64 ? 3 : -1; 877 if (CallbackIdx < 0) continue; 878 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 879 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 880 bool FirstIsConst = isa<ConstantInt>(A0); 881 bool SecondIsConst = isa<ConstantInt>(A1); 882 // If both are const, then we don't need such a comparison. 883 if (FirstIsConst && SecondIsConst) continue; 884 // If only one is const, then make it the first callback argument. 885 if (FirstIsConst || SecondIsConst) { 886 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 887 if (SecondIsConst) 888 std::swap(A0, A1); 889 } 890 891 auto Ty = Type::getIntNTy(*C, TypeSize); 892 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 893 IRB.CreateIntCast(A1, Ty, true)}); 894 } 895 } 896 } 897 898 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 899 size_t Idx, 900 bool IsLeafFunc) { 901 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 902 bool IsEntryBB = &BB == &F.getEntryBlock(); 903 DebugLoc EntryLoc; 904 if (IsEntryBB) { 905 if (auto SP = F.getSubprogram()) 906 EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP); 907 // Keep static allocas and llvm.localescape calls in the entry block. Even 908 // if we aren't splitting the block, it's nice for allocas to be before 909 // calls. 910 IP = PrepareToSplitEntryBlock(BB, IP); 911 } else { 912 EntryLoc = IP->getDebugLoc(); 913 } 914 915 IRBuilder<> IRB(&*IP); 916 IRB.SetCurrentDebugLocation(EntryLoc); 917 if (Options.TracePC) { 918 IRB.CreateCall(SanCovTracePC) 919 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 920 } 921 if (Options.TracePCGuard) { 922 auto GuardPtr = IRB.CreateIntToPtr( 923 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 924 ConstantInt::get(IntptrTy, Idx * 4)), 925 Int32PtrTy); 926 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 927 } 928 if (Options.Inline8bitCounters) { 929 auto CounterPtr = IRB.CreateGEP( 930 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 931 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 932 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 933 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 934 auto Store = IRB.CreateStore(Inc, CounterPtr); 935 SetNoSanitizeMetadata(Load); 936 SetNoSanitizeMetadata(Store); 937 } 938 if (Options.InlineBoolFlag) { 939 auto FlagPtr = IRB.CreateGEP( 940 FunctionBoolArray->getValueType(), FunctionBoolArray, 941 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 942 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 943 auto ThenTerm = 944 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false); 945 IRBuilder<> ThenIRB(ThenTerm); 946 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 947 SetNoSanitizeMetadata(Load); 948 SetNoSanitizeMetadata(Store); 949 } 950 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 951 // Check stack depth. If it's the deepest so far, record it. 952 Module *M = F.getParent(); 953 Function *GetFrameAddr = Intrinsic::getDeclaration( 954 M, Intrinsic::frameaddress, 955 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace())); 956 auto FrameAddrPtr = 957 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 958 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 959 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 960 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 961 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 962 IRBuilder<> ThenIRB(ThenTerm); 963 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 964 SetNoSanitizeMetadata(LowestStack); 965 SetNoSanitizeMetadata(Store); 966 } 967 } 968 969 std::string 970 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 971 if (TargetTriple.isOSBinFormatCOFF()) { 972 if (Section == SanCovCountersSectionName) 973 return ".SCOV$CM"; 974 if (Section == SanCovBoolFlagSectionName) 975 return ".SCOV$BM"; 976 if (Section == SanCovPCsSectionName) 977 return ".SCOVP$M"; 978 return ".SCOV$GM"; // For SanCovGuardsSectionName. 979 } 980 if (TargetTriple.isOSBinFormatMachO()) 981 return "__DATA,__" + Section; 982 return "__" + Section; 983 } 984 985 std::string 986 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 987 if (TargetTriple.isOSBinFormatMachO()) 988 return "\1section$start$__DATA$__" + Section; 989 return "__start___" + Section; 990 } 991 992 std::string 993 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 994 if (TargetTriple.isOSBinFormatMachO()) 995 return "\1section$end$__DATA$__" + Section; 996 return "__stop___" + Section; 997 } 998 999 char ModuleSanitizerCoverageLegacyPass::ID = 0; 1000 INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov", 1001 "Pass for instrumenting coverage on functions", false, 1002 false) 1003 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 1004 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass) 1005 INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov", 1006 "Pass for instrumenting coverage on functions", false, 1007 false) 1008 ModulePass *llvm::createModuleSanitizerCoverageLegacyPassPass( 1009 const SanitizerCoverageOptions &Options, 1010 const std::vector<std::string> &AllowlistFiles, 1011 const std::vector<std::string> &BlocklistFiles) { 1012 return new ModuleSanitizerCoverageLegacyPass(Options, AllowlistFiles, 1013 BlocklistFiles); 1014 } 1015