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/ADT/Triple.h" 17 #include "llvm/Analysis/EHPersonalities.h" 18 #include "llvm/Analysis/PostDominators.h" 19 #include "llvm/IR/Constant.h" 20 #include "llvm/IR/DataLayout.h" 21 #include "llvm/IR/Dominators.h" 22 #include "llvm/IR/Function.h" 23 #include "llvm/IR/GlobalVariable.h" 24 #include "llvm/IR/IRBuilder.h" 25 #include "llvm/IR/IntrinsicInst.h" 26 #include "llvm/IR/Intrinsics.h" 27 #include "llvm/IR/LLVMContext.h" 28 #include "llvm/IR/Module.h" 29 #include "llvm/IR/Type.h" 30 #include "llvm/InitializePasses.h" 31 #include "llvm/Support/CommandLine.h" 32 #include "llvm/Support/SpecialCaseList.h" 33 #include "llvm/Support/VirtualFileSystem.h" 34 #include "llvm/Transforms/Instrumentation.h" 35 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 36 #include "llvm/Transforms/Utils/ModuleUtils.h" 37 38 using namespace llvm; 39 40 #define DEBUG_TYPE "sancov" 41 42 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 43 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 44 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 45 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 46 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 47 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 48 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 49 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 50 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 51 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 52 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 53 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 54 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 55 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 56 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 57 const char SanCovStore1[] = "__sanitizer_cov_store1"; 58 const char SanCovStore2[] = "__sanitizer_cov_store2"; 59 const char SanCovStore4[] = "__sanitizer_cov_store4"; 60 const char SanCovStore8[] = "__sanitizer_cov_store8"; 61 const char SanCovStore16[] = "__sanitizer_cov_store16"; 62 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 63 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 64 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 65 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 66 const char SanCovModuleCtorTracePcGuardName[] = 67 "sancov.module_ctor_trace_pc_guard"; 68 const char SanCovModuleCtor8bitCountersName[] = 69 "sancov.module_ctor_8bit_counters"; 70 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 71 static const uint64_t SanCtorAndDtorPriority = 2; 72 73 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 74 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 75 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 76 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 77 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 78 79 const char SanCovGuardsSectionName[] = "sancov_guards"; 80 const char SanCovCountersSectionName[] = "sancov_cntrs"; 81 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 82 const char SanCovPCsSectionName[] = "sancov_pcs"; 83 84 const char SanCovLowestStackName[] = "__sancov_lowest_stack"; 85 86 static cl::opt<int> ClCoverageLevel( 87 "sanitizer-coverage-level", 88 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 89 "3: all blocks and critical edges"), 90 cl::Hidden, cl::init(0)); 91 92 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 93 cl::desc("Experimental pc tracing"), cl::Hidden, 94 cl::init(false)); 95 96 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 97 cl::desc("pc tracing with a guard"), 98 cl::Hidden, cl::init(false)); 99 100 // If true, we create a global variable that contains PCs of all instrumented 101 // BBs, put this global into a named section, and pass this section's bounds 102 // to __sanitizer_cov_pcs_init. 103 // This way the coverage instrumentation does not need to acquire the PCs 104 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 105 // inline-bool-flag. 106 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 107 cl::desc("create a static PC table"), 108 cl::Hidden, cl::init(false)); 109 110 static cl::opt<bool> 111 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 112 cl::desc("increments 8-bit counter for every edge"), 113 cl::Hidden, cl::init(false)); 114 115 static cl::opt<bool> 116 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 117 cl::desc("sets a boolean flag for every edge"), cl::Hidden, 118 cl::init(false)); 119 120 static cl::opt<bool> 121 ClCMPTracing("sanitizer-coverage-trace-compares", 122 cl::desc("Tracing of CMP and similar instructions"), 123 cl::Hidden, cl::init(false)); 124 125 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 126 cl::desc("Tracing of DIV instructions"), 127 cl::Hidden, cl::init(false)); 128 129 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads", 130 cl::desc("Tracing of load instructions"), 131 cl::Hidden, cl::init(false)); 132 133 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 134 cl::desc("Tracing of store instructions"), 135 cl::Hidden, cl::init(false)); 136 137 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 138 cl::desc("Tracing of GEP instructions"), 139 cl::Hidden, cl::init(false)); 140 141 static cl::opt<bool> 142 ClPruneBlocks("sanitizer-coverage-prune-blocks", 143 cl::desc("Reduce the number of instrumented blocks"), 144 cl::Hidden, cl::init(true)); 145 146 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 147 cl::desc("max stack depth tracing"), 148 cl::Hidden, cl::init(false)); 149 150 namespace { 151 152 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 153 SanitizerCoverageOptions Res; 154 switch (LegacyCoverageLevel) { 155 case 0: 156 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 157 break; 158 case 1: 159 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 160 break; 161 case 2: 162 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 163 break; 164 case 3: 165 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 166 break; 167 case 4: 168 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 169 Res.IndirectCalls = true; 170 break; 171 } 172 return Res; 173 } 174 175 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 176 // Sets CoverageType and IndirectCalls. 177 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 178 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 179 Options.IndirectCalls |= CLOpts.IndirectCalls; 180 Options.TraceCmp |= ClCMPTracing; 181 Options.TraceDiv |= ClDIVTracing; 182 Options.TraceGep |= ClGEPTracing; 183 Options.TracePC |= ClTracePC; 184 Options.TracePCGuard |= ClTracePCGuard; 185 Options.Inline8bitCounters |= ClInline8bitCounters; 186 Options.InlineBoolFlag |= ClInlineBoolFlag; 187 Options.PCTable |= ClCreatePCTable; 188 Options.NoPrune |= !ClPruneBlocks; 189 Options.StackDepth |= ClStackDepth; 190 Options.TraceLoads |= ClLoadTracing; 191 Options.TraceStores |= ClStoreTracing; 192 if (!Options.TracePCGuard && !Options.TracePC && 193 !Options.Inline8bitCounters && !Options.StackDepth && 194 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 195 Options.TracePCGuard = true; // TracePCGuard is default. 196 return Options; 197 } 198 199 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>; 200 using PostDomTreeCallback = 201 function_ref<const PostDominatorTree *(Function &F)>; 202 203 class ModuleSanitizerCoverage { 204 public: 205 ModuleSanitizerCoverage( 206 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 207 const SpecialCaseList *Allowlist = nullptr, 208 const SpecialCaseList *Blocklist = nullptr) 209 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 210 Blocklist(Blocklist) {} 211 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 212 PostDomTreeCallback PDTCallback); 213 214 private: 215 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 216 PostDomTreeCallback PDTCallback); 217 void InjectCoverageForIndirectCalls(Function &F, 218 ArrayRef<Instruction *> IndirCalls); 219 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 220 void InjectTraceForDiv(Function &F, 221 ArrayRef<BinaryOperator *> DivTraceTargets); 222 void InjectTraceForGep(Function &F, 223 ArrayRef<GetElementPtrInst *> GepTraceTargets); 224 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 225 ArrayRef<StoreInst *> Stores); 226 void InjectTraceForSwitch(Function &F, 227 ArrayRef<Instruction *> SwitchTraceTargets); 228 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 229 bool IsLeafFunc = true); 230 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 231 Function &F, Type *Ty, 232 const char *Section); 233 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 234 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 235 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 236 bool IsLeafFunc = true); 237 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 238 const char *InitFunctionName, Type *Ty, 239 const char *Section); 240 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 241 Type *Ty); 242 243 void SetNoSanitizeMetadata(Instruction *I) { 244 I->setMetadata(LLVMContext::MD_nosanitize, MDNode::get(*C, None)); 245 } 246 247 std::string getSectionName(const std::string &Section) const; 248 std::string getSectionStart(const std::string &Section) const; 249 std::string getSectionEnd(const std::string &Section) const; 250 FunctionCallee SanCovTracePCIndir; 251 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 252 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 253 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 254 std::array<FunctionCallee, 5> SanCovLoadFunction; 255 std::array<FunctionCallee, 5> SanCovStoreFunction; 256 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 257 FunctionCallee SanCovTraceGepFunction; 258 FunctionCallee SanCovTraceSwitchFunction; 259 GlobalVariable *SanCovLowestStack; 260 Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, 261 *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, 262 *Int1PtrTy; 263 Module *CurModule; 264 std::string CurModuleUniqueId; 265 Triple TargetTriple; 266 LLVMContext *C; 267 const DataLayout *DL; 268 269 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 270 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 271 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 272 GlobalVariable *FunctionPCsArray; // for pc-table. 273 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 274 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 275 276 SanitizerCoverageOptions Options; 277 278 const SpecialCaseList *Allowlist; 279 const SpecialCaseList *Blocklist; 280 }; 281 282 class ModuleSanitizerCoverageLegacyPass : public ModulePass { 283 public: 284 ModuleSanitizerCoverageLegacyPass( 285 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 286 const std::vector<std::string> &AllowlistFiles = 287 std::vector<std::string>(), 288 const std::vector<std::string> &BlocklistFiles = 289 std::vector<std::string>()) 290 : ModulePass(ID), Options(Options) { 291 if (AllowlistFiles.size() > 0) 292 Allowlist = SpecialCaseList::createOrDie(AllowlistFiles, 293 *vfs::getRealFileSystem()); 294 if (BlocklistFiles.size() > 0) 295 Blocklist = SpecialCaseList::createOrDie(BlocklistFiles, 296 *vfs::getRealFileSystem()); 297 initializeModuleSanitizerCoverageLegacyPassPass( 298 *PassRegistry::getPassRegistry()); 299 } 300 bool runOnModule(Module &M) override { 301 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 302 Blocklist.get()); 303 auto DTCallback = [this](Function &F) -> const DominatorTree * { 304 return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); 305 }; 306 auto PDTCallback = [this](Function &F) -> const PostDominatorTree * { 307 return &this->getAnalysis<PostDominatorTreeWrapperPass>(F) 308 .getPostDomTree(); 309 }; 310 return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback); 311 } 312 313 static char ID; // Pass identification, replacement for typeid 314 StringRef getPassName() const override { return "ModuleSanitizerCoverage"; } 315 316 void getAnalysisUsage(AnalysisUsage &AU) const override { 317 AU.addRequired<DominatorTreeWrapperPass>(); 318 AU.addRequired<PostDominatorTreeWrapperPass>(); 319 } 320 321 private: 322 SanitizerCoverageOptions Options; 323 324 std::unique_ptr<SpecialCaseList> Allowlist; 325 std::unique_ptr<SpecialCaseList> Blocklist; 326 }; 327 328 } // namespace 329 330 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M, 331 ModuleAnalysisManager &MAM) { 332 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 333 Blocklist.get()); 334 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 335 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * { 336 return &FAM.getResult<DominatorTreeAnalysis>(F); 337 }; 338 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * { 339 return &FAM.getResult<PostDominatorTreeAnalysis>(F); 340 }; 341 if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 342 return PreservedAnalyses::none(); 343 return PreservedAnalyses::all(); 344 } 345 346 std::pair<Value *, Value *> 347 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 348 Type *Ty) { 349 // Use ExternalWeak so that if all sections are discarded due to section 350 // garbage collection, the linker will not report undefined symbol errors. 351 // Windows defines the start/stop symbols in compiler-rt so no need for 352 // ExternalWeak. 353 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 354 ? GlobalVariable::ExternalLinkage 355 : GlobalVariable::ExternalWeakLinkage; 356 GlobalVariable *SecStart = 357 new GlobalVariable(M, Ty, false, Linkage, nullptr, 358 getSectionStart(Section)); 359 SecStart->setVisibility(GlobalValue::HiddenVisibility); 360 GlobalVariable *SecEnd = 361 new GlobalVariable(M, Ty, false, Linkage, nullptr, 362 getSectionEnd(Section)); 363 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 364 IRBuilder<> IRB(M.getContext()); 365 if (!TargetTriple.isOSBinFormatCOFF()) 366 return std::make_pair(SecStart, SecEnd); 367 368 // Account for the fact that on windows-msvc __start_* symbols actually 369 // point to a uint64_t before the start of the array. 370 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); 371 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, 372 ConstantInt::get(IntptrTy, sizeof(uint64_t))); 373 return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)), 374 SecEnd); 375 } 376 377 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 378 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 379 const char *Section) { 380 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 381 auto SecStart = SecStartEnd.first; 382 auto SecEnd = SecStartEnd.second; 383 Function *CtorFunc; 384 Type *PtrTy = PointerType::getUnqual(Ty); 385 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 386 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 387 assert(CtorFunc->getName() == CtorName); 388 389 if (TargetTriple.supportsCOMDAT()) { 390 // Use comdat to dedup CtorFunc. 391 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 392 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 393 } else { 394 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 395 } 396 397 if (TargetTriple.isOSBinFormatCOFF()) { 398 // In COFF files, if the contructors are set as COMDAT (they are because 399 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 400 // functions and data) is used, the constructors get stripped. To prevent 401 // this, give the constructors weak ODR linkage and ensure the linker knows 402 // to include the sancov constructor. This way the linker can deduplicate 403 // the constructors but always leave one copy. 404 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 405 } 406 return CtorFunc; 407 } 408 409 bool ModuleSanitizerCoverage::instrumentModule( 410 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 411 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 412 return false; 413 if (Allowlist && 414 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 415 return false; 416 if (Blocklist && 417 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 418 return false; 419 C = &(M.getContext()); 420 DL = &M.getDataLayout(); 421 CurModule = &M; 422 CurModuleUniqueId = getUniqueModuleId(CurModule); 423 TargetTriple = Triple(M.getTargetTriple()); 424 FunctionGuardArray = nullptr; 425 Function8bitCounterArray = nullptr; 426 FunctionBoolArray = nullptr; 427 FunctionPCsArray = nullptr; 428 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 429 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 430 Type *VoidTy = Type::getVoidTy(*C); 431 IRBuilder<> IRB(*C); 432 Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty()); 433 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 434 Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty()); 435 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 436 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 437 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty()); 438 Int64Ty = IRB.getInt64Ty(); 439 Int32Ty = IRB.getInt32Ty(); 440 Int16Ty = IRB.getInt16Ty(); 441 Int8Ty = IRB.getInt8Ty(); 442 Int1Ty = IRB.getInt1Ty(); 443 444 SanCovTracePCIndir = 445 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 446 // Make sure smaller parameters are zero-extended to i64 if required by the 447 // target ABI. 448 AttributeList SanCovTraceCmpZeroExtAL; 449 SanCovTraceCmpZeroExtAL = 450 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 451 SanCovTraceCmpZeroExtAL = 452 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 453 454 SanCovTraceCmpFunction[0] = 455 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 456 IRB.getInt8Ty(), IRB.getInt8Ty()); 457 SanCovTraceCmpFunction[1] = 458 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 459 IRB.getInt16Ty(), IRB.getInt16Ty()); 460 SanCovTraceCmpFunction[2] = 461 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 462 IRB.getInt32Ty(), IRB.getInt32Ty()); 463 SanCovTraceCmpFunction[3] = 464 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 465 466 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 467 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 468 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 469 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 470 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 471 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 472 SanCovTraceConstCmpFunction[3] = 473 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 474 475 // Loads. 476 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy); 477 SanCovLoadFunction[1] = 478 M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy); 479 SanCovLoadFunction[2] = 480 M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy); 481 SanCovLoadFunction[3] = 482 M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy); 483 SanCovLoadFunction[4] = 484 M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy); 485 // Stores. 486 SanCovStoreFunction[0] = 487 M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy); 488 SanCovStoreFunction[1] = 489 M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy); 490 SanCovStoreFunction[2] = 491 M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy); 492 SanCovStoreFunction[3] = 493 M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy); 494 SanCovStoreFunction[4] = 495 M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy); 496 497 { 498 AttributeList AL; 499 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 500 SanCovTraceDivFunction[0] = 501 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 502 } 503 SanCovTraceDivFunction[1] = 504 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 505 SanCovTraceGepFunction = 506 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 507 SanCovTraceSwitchFunction = 508 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); 509 510 Constant *SanCovLowestStackConstant = 511 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 512 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 513 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 514 C->emitError(StringRef("'") + SanCovLowestStackName + 515 "' should not be declared by the user"); 516 return true; 517 } 518 SanCovLowestStack->setThreadLocalMode( 519 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 520 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 521 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 522 523 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 524 SanCovTracePCGuard = 525 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); 526 527 for (auto &F : M) 528 instrumentFunction(F, DTCallback, PDTCallback); 529 530 Function *Ctor = nullptr; 531 532 if (FunctionGuardArray) 533 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 534 SanCovTracePCGuardInitName, Int32Ty, 535 SanCovGuardsSectionName); 536 if (Function8bitCounterArray) 537 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 538 SanCov8bitCountersInitName, Int8Ty, 539 SanCovCountersSectionName); 540 if (FunctionBoolArray) { 541 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 542 SanCovBoolFlagInitName, Int1Ty, 543 SanCovBoolFlagSectionName); 544 } 545 if (Ctor && Options.PCTable) { 546 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 547 FunctionCallee InitFunction = declareSanitizerInitFunction( 548 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 549 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 550 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 551 } 552 appendToUsed(M, GlobalsToAppendToUsed); 553 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 554 return true; 555 } 556 557 // True if block has successors and it dominates all of them. 558 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 559 if (succ_empty(BB)) 560 return false; 561 562 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 563 return DT->dominates(BB, SUCC); 564 }); 565 } 566 567 // True if block has predecessors and it postdominates all of them. 568 static bool isFullPostDominator(const BasicBlock *BB, 569 const PostDominatorTree *PDT) { 570 if (pred_empty(BB)) 571 return false; 572 573 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 574 return PDT->dominates(BB, PRED); 575 }); 576 } 577 578 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 579 const DominatorTree *DT, 580 const PostDominatorTree *PDT, 581 const SanitizerCoverageOptions &Options) { 582 // Don't insert coverage for blocks containing nothing but unreachable: we 583 // will never call __sanitizer_cov() for them, so counting them in 584 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 585 // percentage. Also, unreachable instructions frequently have no debug 586 // locations. 587 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 588 return false; 589 590 // Don't insert coverage into blocks without a valid insertion point 591 // (catchswitch blocks). 592 if (BB->getFirstInsertionPt() == BB->end()) 593 return false; 594 595 if (Options.NoPrune || &F.getEntryBlock() == BB) 596 return true; 597 598 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 599 &F.getEntryBlock() != BB) 600 return false; 601 602 // Do not instrument full dominators, or full post-dominators with multiple 603 // predecessors. 604 return !isFullDominator(BB, DT) 605 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 606 } 607 608 609 // Returns true iff From->To is a backedge. 610 // A twist here is that we treat From->To as a backedge if 611 // * To dominates From or 612 // * To->UniqueSuccessor dominates From 613 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 614 const DominatorTree *DT) { 615 if (DT->dominates(To, From)) 616 return true; 617 if (auto Next = To->getUniqueSuccessor()) 618 if (DT->dominates(Next, From)) 619 return true; 620 return false; 621 } 622 623 // Prunes uninteresting Cmp instrumentation: 624 // * CMP instructions that feed into loop backedge branch. 625 // 626 // Note that Cmp pruning is controlled by the same flag as the 627 // BB pruning. 628 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, 629 const SanitizerCoverageOptions &Options) { 630 if (!Options.NoPrune) 631 if (CMP->hasOneUse()) 632 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 633 for (BasicBlock *B : BR->successors()) 634 if (IsBackEdge(BR->getParent(), B, DT)) 635 return false; 636 return true; 637 } 638 639 void ModuleSanitizerCoverage::instrumentFunction( 640 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 641 if (F.empty()) 642 return; 643 if (F.getName().find(".module_ctor") != std::string::npos) 644 return; // Should not instrument sanitizer init functions. 645 if (F.getName().startswith("__sanitizer_")) 646 return; // Don't instrument __sanitizer_* callbacks. 647 // Don't touch available_externally functions, their actual body is elewhere. 648 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 649 return; 650 // Don't instrument MSVC CRT configuration helpers. They may run before normal 651 // initialization. 652 if (F.getName() == "__local_stdio_printf_options" || 653 F.getName() == "__local_stdio_scanf_options") 654 return; 655 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 656 return; 657 // Don't instrument functions using SEH for now. Splitting basic blocks like 658 // we do for coverage breaks WinEHPrepare. 659 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 660 if (F.hasPersonalityFn() && 661 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 662 return; 663 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 664 return; 665 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 666 return; 667 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 668 return; 669 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 670 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 671 SmallVector<Instruction *, 8> IndirCalls; 672 SmallVector<BasicBlock *, 16> BlocksToInstrument; 673 SmallVector<Instruction *, 8> CmpTraceTargets; 674 SmallVector<Instruction *, 8> SwitchTraceTargets; 675 SmallVector<BinaryOperator *, 8> DivTraceTargets; 676 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 677 SmallVector<LoadInst *, 8> Loads; 678 SmallVector<StoreInst *, 8> Stores; 679 680 const DominatorTree *DT = DTCallback(F); 681 const PostDominatorTree *PDT = PDTCallback(F); 682 bool IsLeafFunc = true; 683 684 for (auto &BB : F) { 685 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 686 BlocksToInstrument.push_back(&BB); 687 for (auto &Inst : BB) { 688 if (Options.IndirectCalls) { 689 CallBase *CB = dyn_cast<CallBase>(&Inst); 690 if (CB && CB->isIndirectCall()) 691 IndirCalls.push_back(&Inst); 692 } 693 if (Options.TraceCmp) { 694 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 695 if (IsInterestingCmp(CMP, DT, Options)) 696 CmpTraceTargets.push_back(&Inst); 697 if (isa<SwitchInst>(&Inst)) 698 SwitchTraceTargets.push_back(&Inst); 699 } 700 if (Options.TraceDiv) 701 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 702 if (BO->getOpcode() == Instruction::SDiv || 703 BO->getOpcode() == Instruction::UDiv) 704 DivTraceTargets.push_back(BO); 705 if (Options.TraceGep) 706 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 707 GepTraceTargets.push_back(GEP); 708 if (Options.TraceLoads) 709 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 710 Loads.push_back(LI); 711 if (Options.TraceStores) 712 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 713 Stores.push_back(SI); 714 if (Options.StackDepth) 715 if (isa<InvokeInst>(Inst) || 716 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 717 IsLeafFunc = false; 718 } 719 } 720 721 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 722 InjectCoverageForIndirectCalls(F, IndirCalls); 723 InjectTraceForCmp(F, CmpTraceTargets); 724 InjectTraceForSwitch(F, SwitchTraceTargets); 725 InjectTraceForDiv(F, DivTraceTargets); 726 InjectTraceForGep(F, GepTraceTargets); 727 InjectTraceForLoadsAndStores(F, Loads, Stores); 728 } 729 730 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 731 size_t NumElements, Function &F, Type *Ty, const char *Section) { 732 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 733 auto Array = new GlobalVariable( 734 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 735 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 736 737 if (TargetTriple.supportsCOMDAT() && 738 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 739 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 740 Array->setComdat(Comdat); 741 Array->setSection(getSectionName(Section)); 742 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize())); 743 744 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 745 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 746 // section(s) as a unit, so we conservatively retain all unconditionally in 747 // the compiler. 748 // 749 // With comdat (COFF/ELF), the linker can guarantee the associated sections 750 // will be retained or discarded as a unit, so llvm.compiler.used is 751 // sufficient. Otherwise, conservatively make all of them retained by the 752 // linker. 753 if (Array->hasComdat()) 754 GlobalsToAppendToCompilerUsed.push_back(Array); 755 else 756 GlobalsToAppendToUsed.push_back(Array); 757 758 return Array; 759 } 760 761 GlobalVariable * 762 ModuleSanitizerCoverage::CreatePCArray(Function &F, 763 ArrayRef<BasicBlock *> AllBlocks) { 764 size_t N = AllBlocks.size(); 765 assert(N); 766 SmallVector<Constant *, 32> PCs; 767 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 768 for (size_t i = 0; i < N; i++) { 769 if (&F.getEntryBlock() == AllBlocks[i]) { 770 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 771 PCs.push_back((Constant *)IRB.CreateIntToPtr( 772 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 773 } else { 774 PCs.push_back((Constant *)IRB.CreatePointerCast( 775 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 776 PCs.push_back((Constant *)IRB.CreateIntToPtr( 777 ConstantInt::get(IntptrTy, 0), IntptrPtrTy)); 778 } 779 } 780 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 781 SanCovPCsSectionName); 782 PCArray->setInitializer( 783 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 784 PCArray->setConstant(true); 785 786 return PCArray; 787 } 788 789 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 790 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 791 if (Options.TracePCGuard) 792 FunctionGuardArray = CreateFunctionLocalArrayInSection( 793 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 794 795 if (Options.Inline8bitCounters) 796 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 797 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 798 if (Options.InlineBoolFlag) 799 FunctionBoolArray = CreateFunctionLocalArrayInSection( 800 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 801 802 if (Options.PCTable) 803 FunctionPCsArray = CreatePCArray(F, AllBlocks); 804 } 805 806 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 807 ArrayRef<BasicBlock *> AllBlocks, 808 bool IsLeafFunc) { 809 if (AllBlocks.empty()) return false; 810 CreateFunctionLocalArrays(F, AllBlocks); 811 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 812 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 813 return true; 814 } 815 816 // On every indirect call we call a run-time function 817 // __sanitizer_cov_indir_call* with two parameters: 818 // - callee address, 819 // - global cache array that contains CacheSize pointers (zero-initialized). 820 // The cache is used to speed up recording the caller-callee pairs. 821 // The address of the caller is passed implicitly via caller PC. 822 // CacheSize is encoded in the name of the run-time function. 823 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 824 Function &F, ArrayRef<Instruction *> IndirCalls) { 825 if (IndirCalls.empty()) 826 return; 827 assert(Options.TracePC || Options.TracePCGuard || 828 Options.Inline8bitCounters || Options.InlineBoolFlag); 829 for (auto I : IndirCalls) { 830 IRBuilder<> IRB(I); 831 CallBase &CB = cast<CallBase>(*I); 832 Value *Callee = CB.getCalledOperand(); 833 if (isa<InlineAsm>(Callee)) 834 continue; 835 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 836 } 837 } 838 839 // For every switch statement we insert a call: 840 // __sanitizer_cov_trace_switch(CondValue, 841 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 842 843 void ModuleSanitizerCoverage::InjectTraceForSwitch( 844 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 845 for (auto I : SwitchTraceTargets) { 846 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 847 IRBuilder<> IRB(I); 848 SmallVector<Constant *, 16> Initializers; 849 Value *Cond = SI->getCondition(); 850 if (Cond->getType()->getScalarSizeInBits() > 851 Int64Ty->getScalarSizeInBits()) 852 continue; 853 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 854 Initializers.push_back( 855 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 856 if (Cond->getType()->getScalarSizeInBits() < 857 Int64Ty->getScalarSizeInBits()) 858 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 859 for (auto It : SI->cases()) { 860 Constant *C = It.getCaseValue(); 861 if (C->getType()->getScalarSizeInBits() < 862 Int64Ty->getScalarSizeInBits()) 863 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 864 Initializers.push_back(C); 865 } 866 llvm::sort(drop_begin(Initializers, 2), 867 [](const Constant *A, const Constant *B) { 868 return cast<ConstantInt>(A)->getLimitedValue() < 869 cast<ConstantInt>(B)->getLimitedValue(); 870 }); 871 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 872 GlobalVariable *GV = new GlobalVariable( 873 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 874 ConstantArray::get(ArrayOfInt64Ty, Initializers), 875 "__sancov_gen_cov_switch_values"); 876 IRB.CreateCall(SanCovTraceSwitchFunction, 877 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 878 } 879 } 880 } 881 882 void ModuleSanitizerCoverage::InjectTraceForDiv( 883 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 884 for (auto BO : DivTraceTargets) { 885 IRBuilder<> IRB(BO); 886 Value *A1 = BO->getOperand(1); 887 if (isa<ConstantInt>(A1)) continue; 888 if (!A1->getType()->isIntegerTy()) 889 continue; 890 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 891 int CallbackIdx = TypeSize == 32 ? 0 : 892 TypeSize == 64 ? 1 : -1; 893 if (CallbackIdx < 0) continue; 894 auto Ty = Type::getIntNTy(*C, TypeSize); 895 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 896 {IRB.CreateIntCast(A1, Ty, true)}); 897 } 898 } 899 900 void ModuleSanitizerCoverage::InjectTraceForGep( 901 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 902 for (auto GEP : GepTraceTargets) { 903 IRBuilder<> IRB(GEP); 904 for (Use &Idx : GEP->indices()) 905 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 906 IRB.CreateCall(SanCovTraceGepFunction, 907 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 908 } 909 } 910 911 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 912 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 913 auto CallbackIdx = [&](Type *ElementTy) -> int { 914 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 915 return TypeSize == 8 ? 0 916 : TypeSize == 16 ? 1 917 : TypeSize == 32 ? 2 918 : TypeSize == 64 ? 3 919 : TypeSize == 128 ? 4 920 : -1; 921 }; 922 Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy, 923 Int128PtrTy}; 924 for (auto LI : Loads) { 925 IRBuilder<> IRB(LI); 926 auto Ptr = LI->getPointerOperand(); 927 int Idx = CallbackIdx(LI->getType()); 928 if (Idx < 0) 929 continue; 930 IRB.CreateCall(SanCovLoadFunction[Idx], 931 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 932 } 933 for (auto SI : Stores) { 934 IRBuilder<> IRB(SI); 935 auto Ptr = SI->getPointerOperand(); 936 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 937 if (Idx < 0) 938 continue; 939 IRB.CreateCall(SanCovStoreFunction[Idx], 940 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 941 } 942 } 943 944 void ModuleSanitizerCoverage::InjectTraceForCmp( 945 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 946 for (auto I : CmpTraceTargets) { 947 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 948 IRBuilder<> IRB(ICMP); 949 Value *A0 = ICMP->getOperand(0); 950 Value *A1 = ICMP->getOperand(1); 951 if (!A0->getType()->isIntegerTy()) 952 continue; 953 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 954 int CallbackIdx = TypeSize == 8 ? 0 : 955 TypeSize == 16 ? 1 : 956 TypeSize == 32 ? 2 : 957 TypeSize == 64 ? 3 : -1; 958 if (CallbackIdx < 0) continue; 959 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 960 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 961 bool FirstIsConst = isa<ConstantInt>(A0); 962 bool SecondIsConst = isa<ConstantInt>(A1); 963 // If both are const, then we don't need such a comparison. 964 if (FirstIsConst && SecondIsConst) continue; 965 // If only one is const, then make it the first callback argument. 966 if (FirstIsConst || SecondIsConst) { 967 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 968 if (SecondIsConst) 969 std::swap(A0, A1); 970 } 971 972 auto Ty = Type::getIntNTy(*C, TypeSize); 973 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 974 IRB.CreateIntCast(A1, Ty, true)}); 975 } 976 } 977 } 978 979 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 980 size_t Idx, 981 bool IsLeafFunc) { 982 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 983 bool IsEntryBB = &BB == &F.getEntryBlock(); 984 DebugLoc EntryLoc; 985 if (IsEntryBB) { 986 if (auto SP = F.getSubprogram()) 987 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 988 // Keep static allocas and llvm.localescape calls in the entry block. Even 989 // if we aren't splitting the block, it's nice for allocas to be before 990 // calls. 991 IP = PrepareToSplitEntryBlock(BB, IP); 992 } 993 994 InstrumentationIRBuilder IRB(&*IP); 995 if (EntryLoc) 996 IRB.SetCurrentDebugLocation(EntryLoc); 997 if (Options.TracePC) { 998 IRB.CreateCall(SanCovTracePC) 999 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 1000 } 1001 if (Options.TracePCGuard) { 1002 auto GuardPtr = IRB.CreateIntToPtr( 1003 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 1004 ConstantInt::get(IntptrTy, Idx * 4)), 1005 Int32PtrTy); 1006 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 1007 } 1008 if (Options.Inline8bitCounters) { 1009 auto CounterPtr = IRB.CreateGEP( 1010 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 1011 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1012 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 1013 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 1014 auto Store = IRB.CreateStore(Inc, CounterPtr); 1015 SetNoSanitizeMetadata(Load); 1016 SetNoSanitizeMetadata(Store); 1017 } 1018 if (Options.InlineBoolFlag) { 1019 auto FlagPtr = IRB.CreateGEP( 1020 FunctionBoolArray->getValueType(), FunctionBoolArray, 1021 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1022 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 1023 auto ThenTerm = 1024 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false); 1025 IRBuilder<> ThenIRB(ThenTerm); 1026 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 1027 SetNoSanitizeMetadata(Load); 1028 SetNoSanitizeMetadata(Store); 1029 } 1030 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 1031 // Check stack depth. If it's the deepest so far, record it. 1032 Module *M = F.getParent(); 1033 Function *GetFrameAddr = Intrinsic::getDeclaration( 1034 M, Intrinsic::frameaddress, 1035 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace())); 1036 auto FrameAddrPtr = 1037 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 1038 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1039 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1040 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1041 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 1042 IRBuilder<> ThenIRB(ThenTerm); 1043 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1044 SetNoSanitizeMetadata(LowestStack); 1045 SetNoSanitizeMetadata(Store); 1046 } 1047 } 1048 1049 std::string 1050 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1051 if (TargetTriple.isOSBinFormatCOFF()) { 1052 if (Section == SanCovCountersSectionName) 1053 return ".SCOV$CM"; 1054 if (Section == SanCovBoolFlagSectionName) 1055 return ".SCOV$BM"; 1056 if (Section == SanCovPCsSectionName) 1057 return ".SCOVP$M"; 1058 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1059 } 1060 if (TargetTriple.isOSBinFormatMachO()) 1061 return "__DATA,__" + Section; 1062 return "__" + Section; 1063 } 1064 1065 std::string 1066 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1067 if (TargetTriple.isOSBinFormatMachO()) 1068 return "\1section$start$__DATA$__" + Section; 1069 return "__start___" + Section; 1070 } 1071 1072 std::string 1073 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1074 if (TargetTriple.isOSBinFormatMachO()) 1075 return "\1section$end$__DATA$__" + Section; 1076 return "__stop___" + Section; 1077 } 1078 1079 char ModuleSanitizerCoverageLegacyPass::ID = 0; 1080 INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov", 1081 "Pass for instrumenting coverage on functions", false, 1082 false) 1083 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 1084 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass) 1085 INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov", 1086 "Pass for instrumenting coverage on functions", false, 1087 false) 1088 ModulePass *llvm::createModuleSanitizerCoverageLegacyPassPass( 1089 const SanitizerCoverageOptions &Options, 1090 const std::vector<std::string> &AllowlistFiles, 1091 const std::vector<std::string> &BlocklistFiles) { 1092 return new ModuleSanitizerCoverageLegacyPass(Options, AllowlistFiles, 1093 BlocklistFiles); 1094 } 1095