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 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 49 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 50 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 51 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 52 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 53 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 54 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 55 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 56 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 57 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 58 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 59 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 60 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 61 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 62 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 63 const char SanCovStore1[] = "__sanitizer_cov_store1"; 64 const char SanCovStore2[] = "__sanitizer_cov_store2"; 65 const char SanCovStore4[] = "__sanitizer_cov_store4"; 66 const char SanCovStore8[] = "__sanitizer_cov_store8"; 67 const char SanCovStore16[] = "__sanitizer_cov_store16"; 68 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 69 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 70 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 71 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 72 const char SanCovModuleCtorTracePcGuardName[] = 73 "sancov.module_ctor_trace_pc_guard"; 74 const char SanCovModuleCtor8bitCountersName[] = 75 "sancov.module_ctor_8bit_counters"; 76 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 77 static const uint64_t SanCtorAndDtorPriority = 2; 78 79 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 80 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 81 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 82 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 83 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 84 85 const char SanCovGuardsSectionName[] = "sancov_guards"; 86 const char SanCovCountersSectionName[] = "sancov_cntrs"; 87 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 88 const char SanCovPCsSectionName[] = "sancov_pcs"; 89 90 const char 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> ClLoadTracing("sanitizer-coverage-trace-loads", 136 cl::desc("Tracing of load instructions"), 137 cl::Hidden, cl::init(false)); 138 139 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 140 cl::desc("Tracing of store instructions"), 141 cl::Hidden, cl::init(false)); 142 143 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 144 cl::desc("Tracing of GEP instructions"), 145 cl::Hidden, cl::init(false)); 146 147 static cl::opt<bool> 148 ClPruneBlocks("sanitizer-coverage-prune-blocks", 149 cl::desc("Reduce the number of instrumented blocks"), 150 cl::Hidden, cl::init(true)); 151 152 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 153 cl::desc("max stack depth tracing"), 154 cl::Hidden, cl::init(false)); 155 156 namespace { 157 158 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 159 SanitizerCoverageOptions Res; 160 switch (LegacyCoverageLevel) { 161 case 0: 162 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 163 break; 164 case 1: 165 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 166 break; 167 case 2: 168 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 169 break; 170 case 3: 171 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 172 break; 173 case 4: 174 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 175 Res.IndirectCalls = true; 176 break; 177 } 178 return Res; 179 } 180 181 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 182 // Sets CoverageType and IndirectCalls. 183 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 184 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 185 Options.IndirectCalls |= CLOpts.IndirectCalls; 186 Options.TraceCmp |= ClCMPTracing; 187 Options.TraceDiv |= ClDIVTracing; 188 Options.TraceGep |= ClGEPTracing; 189 Options.TracePC |= ClTracePC; 190 Options.TracePCGuard |= ClTracePCGuard; 191 Options.Inline8bitCounters |= ClInline8bitCounters; 192 Options.InlineBoolFlag |= ClInlineBoolFlag; 193 Options.PCTable |= ClCreatePCTable; 194 Options.NoPrune |= !ClPruneBlocks; 195 Options.StackDepth |= ClStackDepth; 196 Options.TraceLoads |= ClLoadTracing; 197 Options.TraceStores |= ClStoreTracing; 198 if (!Options.TracePCGuard && !Options.TracePC && 199 !Options.Inline8bitCounters && !Options.StackDepth && 200 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 201 Options.TracePCGuard = true; // TracePCGuard is default. 202 return Options; 203 } 204 205 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>; 206 using PostDomTreeCallback = 207 function_ref<const PostDominatorTree *(Function &F)>; 208 209 class ModuleSanitizerCoverage { 210 public: 211 ModuleSanitizerCoverage( 212 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 213 const SpecialCaseList *Allowlist = nullptr, 214 const SpecialCaseList *Blocklist = nullptr) 215 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 216 Blocklist(Blocklist) {} 217 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 218 PostDomTreeCallback PDTCallback); 219 220 private: 221 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 222 PostDomTreeCallback PDTCallback); 223 void InjectCoverageForIndirectCalls(Function &F, 224 ArrayRef<Instruction *> IndirCalls); 225 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 226 void InjectTraceForDiv(Function &F, 227 ArrayRef<BinaryOperator *> DivTraceTargets); 228 void InjectTraceForGep(Function &F, 229 ArrayRef<GetElementPtrInst *> GepTraceTargets); 230 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 231 ArrayRef<StoreInst *> Stores); 232 void InjectTraceForSwitch(Function &F, 233 ArrayRef<Instruction *> SwitchTraceTargets); 234 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 235 bool IsLeafFunc = true); 236 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 237 Function &F, Type *Ty, 238 const char *Section); 239 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 240 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 241 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 242 bool IsLeafFunc = true); 243 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 244 const char *InitFunctionName, Type *Ty, 245 const char *Section); 246 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 247 Type *Ty); 248 249 void SetNoSanitizeMetadata(Instruction *I) { 250 I->setMetadata(I->getModule()->getMDKindID("nosanitize"), 251 MDNode::get(*C, None)); 252 } 253 254 std::string getSectionName(const std::string &Section) const; 255 std::string getSectionStart(const std::string &Section) const; 256 std::string getSectionEnd(const std::string &Section) const; 257 FunctionCallee SanCovTracePCIndir; 258 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 259 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 260 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 261 std::array<FunctionCallee, 5> SanCovLoadFunction; 262 std::array<FunctionCallee, 5> SanCovStoreFunction; 263 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 264 FunctionCallee SanCovTraceGepFunction; 265 FunctionCallee SanCovTraceSwitchFunction; 266 GlobalVariable *SanCovLowestStack; 267 Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, 268 *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, 269 *Int1PtrTy; 270 Module *CurModule; 271 std::string CurModuleUniqueId; 272 Triple TargetTriple; 273 LLVMContext *C; 274 const DataLayout *DL; 275 276 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 277 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 278 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 279 GlobalVariable *FunctionPCsArray; // for pc-table. 280 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 281 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 282 283 SanitizerCoverageOptions Options; 284 285 const SpecialCaseList *Allowlist; 286 const SpecialCaseList *Blocklist; 287 }; 288 289 class ModuleSanitizerCoverageLegacyPass : public ModulePass { 290 public: 291 ModuleSanitizerCoverageLegacyPass( 292 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 293 const std::vector<std::string> &AllowlistFiles = 294 std::vector<std::string>(), 295 const std::vector<std::string> &BlocklistFiles = 296 std::vector<std::string>()) 297 : ModulePass(ID), Options(Options) { 298 if (AllowlistFiles.size() > 0) 299 Allowlist = SpecialCaseList::createOrDie(AllowlistFiles, 300 *vfs::getRealFileSystem()); 301 if (BlocklistFiles.size() > 0) 302 Blocklist = SpecialCaseList::createOrDie(BlocklistFiles, 303 *vfs::getRealFileSystem()); 304 initializeModuleSanitizerCoverageLegacyPassPass( 305 *PassRegistry::getPassRegistry()); 306 } 307 bool runOnModule(Module &M) override { 308 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 309 Blocklist.get()); 310 auto DTCallback = [this](Function &F) -> const DominatorTree * { 311 return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); 312 }; 313 auto PDTCallback = [this](Function &F) -> const PostDominatorTree * { 314 return &this->getAnalysis<PostDominatorTreeWrapperPass>(F) 315 .getPostDomTree(); 316 }; 317 return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback); 318 } 319 320 static char ID; // Pass identification, replacement for typeid 321 StringRef getPassName() const override { return "ModuleSanitizerCoverage"; } 322 323 void getAnalysisUsage(AnalysisUsage &AU) const override { 324 AU.addRequired<DominatorTreeWrapperPass>(); 325 AU.addRequired<PostDominatorTreeWrapperPass>(); 326 } 327 328 private: 329 SanitizerCoverageOptions Options; 330 331 std::unique_ptr<SpecialCaseList> Allowlist; 332 std::unique_ptr<SpecialCaseList> Blocklist; 333 }; 334 335 } // namespace 336 337 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M, 338 ModuleAnalysisManager &MAM) { 339 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 340 Blocklist.get()); 341 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 342 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * { 343 return &FAM.getResult<DominatorTreeAnalysis>(F); 344 }; 345 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * { 346 return &FAM.getResult<PostDominatorTreeAnalysis>(F); 347 }; 348 if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 349 return PreservedAnalyses::none(); 350 return PreservedAnalyses::all(); 351 } 352 353 std::pair<Value *, Value *> 354 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 355 Type *Ty) { 356 // Use ExternalWeak so that if all sections are discarded due to section 357 // garbage collection, the linker will not report undefined symbol errors. 358 // Windows defines the start/stop symbols in compiler-rt so no need for 359 // ExternalWeak. 360 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 361 ? GlobalVariable::ExternalLinkage 362 : GlobalVariable::ExternalWeakLinkage; 363 GlobalVariable *SecStart = 364 new GlobalVariable(M, Ty, false, Linkage, nullptr, 365 getSectionStart(Section)); 366 SecStart->setVisibility(GlobalValue::HiddenVisibility); 367 GlobalVariable *SecEnd = 368 new GlobalVariable(M, Ty, false, Linkage, nullptr, 369 getSectionEnd(Section)); 370 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 371 IRBuilder<> IRB(M.getContext()); 372 if (!TargetTriple.isOSBinFormatCOFF()) 373 return std::make_pair(SecStart, SecEnd); 374 375 // Account for the fact that on windows-msvc __start_* symbols actually 376 // point to a uint64_t before the start of the array. 377 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); 378 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, 379 ConstantInt::get(IntptrTy, sizeof(uint64_t))); 380 return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)), 381 SecEnd); 382 } 383 384 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 385 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 386 const char *Section) { 387 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 388 auto SecStart = SecStartEnd.first; 389 auto SecEnd = SecStartEnd.second; 390 Function *CtorFunc; 391 Type *PtrTy = PointerType::getUnqual(Ty); 392 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 393 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 394 assert(CtorFunc->getName() == CtorName); 395 396 if (TargetTriple.supportsCOMDAT()) { 397 // Use comdat to dedup CtorFunc. 398 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 399 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 400 } else { 401 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 402 } 403 404 if (TargetTriple.isOSBinFormatCOFF()) { 405 // In COFF files, if the contructors are set as COMDAT (they are because 406 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 407 // functions and data) is used, the constructors get stripped. To prevent 408 // this, give the constructors weak ODR linkage and ensure the linker knows 409 // to include the sancov constructor. This way the linker can deduplicate 410 // the constructors but always leave one copy. 411 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 412 } 413 return CtorFunc; 414 } 415 416 bool ModuleSanitizerCoverage::instrumentModule( 417 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 418 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 419 return false; 420 if (Allowlist && 421 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 422 return false; 423 if (Blocklist && 424 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 425 return false; 426 C = &(M.getContext()); 427 DL = &M.getDataLayout(); 428 CurModule = &M; 429 CurModuleUniqueId = getUniqueModuleId(CurModule); 430 TargetTriple = Triple(M.getTargetTriple()); 431 FunctionGuardArray = nullptr; 432 Function8bitCounterArray = nullptr; 433 FunctionBoolArray = nullptr; 434 FunctionPCsArray = nullptr; 435 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 436 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 437 Type *VoidTy = Type::getVoidTy(*C); 438 IRBuilder<> IRB(*C); 439 Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty()); 440 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 441 Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty()); 442 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 443 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 444 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty()); 445 Int64Ty = IRB.getInt64Ty(); 446 Int32Ty = IRB.getInt32Ty(); 447 Int16Ty = IRB.getInt16Ty(); 448 Int8Ty = IRB.getInt8Ty(); 449 Int1Ty = IRB.getInt1Ty(); 450 451 SanCovTracePCIndir = 452 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 453 // Make sure smaller parameters are zero-extended to i64 if required by the 454 // target ABI. 455 AttributeList SanCovTraceCmpZeroExtAL; 456 SanCovTraceCmpZeroExtAL = 457 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 458 SanCovTraceCmpZeroExtAL = 459 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 460 461 SanCovTraceCmpFunction[0] = 462 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 463 IRB.getInt8Ty(), IRB.getInt8Ty()); 464 SanCovTraceCmpFunction[1] = 465 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 466 IRB.getInt16Ty(), IRB.getInt16Ty()); 467 SanCovTraceCmpFunction[2] = 468 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 469 IRB.getInt32Ty(), IRB.getInt32Ty()); 470 SanCovTraceCmpFunction[3] = 471 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 472 473 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 474 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 475 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 476 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 477 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 478 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 479 SanCovTraceConstCmpFunction[3] = 480 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 481 482 // Loads. 483 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy); 484 SanCovLoadFunction[1] = 485 M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy); 486 SanCovLoadFunction[2] = 487 M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy); 488 SanCovLoadFunction[3] = 489 M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy); 490 SanCovLoadFunction[4] = 491 M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy); 492 // Stores. 493 SanCovStoreFunction[0] = 494 M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy); 495 SanCovStoreFunction[1] = 496 M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy); 497 SanCovStoreFunction[2] = 498 M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy); 499 SanCovStoreFunction[3] = 500 M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy); 501 SanCovStoreFunction[4] = 502 M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy); 503 504 { 505 AttributeList AL; 506 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 507 SanCovTraceDivFunction[0] = 508 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 509 } 510 SanCovTraceDivFunction[1] = 511 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 512 SanCovTraceGepFunction = 513 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 514 SanCovTraceSwitchFunction = 515 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); 516 517 Constant *SanCovLowestStackConstant = 518 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 519 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 520 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 521 C->emitError(StringRef("'") + SanCovLowestStackName + 522 "' should not be declared by the user"); 523 return true; 524 } 525 SanCovLowestStack->setThreadLocalMode( 526 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 527 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 528 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 529 530 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 531 SanCovTracePCGuard = 532 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); 533 534 for (auto &F : M) 535 instrumentFunction(F, DTCallback, PDTCallback); 536 537 Function *Ctor = nullptr; 538 539 if (FunctionGuardArray) 540 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 541 SanCovTracePCGuardInitName, Int32Ty, 542 SanCovGuardsSectionName); 543 if (Function8bitCounterArray) 544 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 545 SanCov8bitCountersInitName, Int8Ty, 546 SanCovCountersSectionName); 547 if (FunctionBoolArray) { 548 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 549 SanCovBoolFlagInitName, Int1Ty, 550 SanCovBoolFlagSectionName); 551 } 552 if (Ctor && Options.PCTable) { 553 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 554 FunctionCallee InitFunction = declareSanitizerInitFunction( 555 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 556 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 557 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 558 } 559 appendToUsed(M, GlobalsToAppendToUsed); 560 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 561 return true; 562 } 563 564 // True if block has successors and it dominates all of them. 565 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 566 if (succ_empty(BB)) 567 return false; 568 569 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 570 return DT->dominates(BB, SUCC); 571 }); 572 } 573 574 // True if block has predecessors and it postdominates all of them. 575 static bool isFullPostDominator(const BasicBlock *BB, 576 const PostDominatorTree *PDT) { 577 if (pred_empty(BB)) 578 return false; 579 580 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 581 return PDT->dominates(BB, PRED); 582 }); 583 } 584 585 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 586 const DominatorTree *DT, 587 const PostDominatorTree *PDT, 588 const SanitizerCoverageOptions &Options) { 589 // Don't insert coverage for blocks containing nothing but unreachable: we 590 // will never call __sanitizer_cov() for them, so counting them in 591 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 592 // percentage. Also, unreachable instructions frequently have no debug 593 // locations. 594 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 595 return false; 596 597 // Don't insert coverage into blocks without a valid insertion point 598 // (catchswitch blocks). 599 if (BB->getFirstInsertionPt() == BB->end()) 600 return false; 601 602 if (Options.NoPrune || &F.getEntryBlock() == BB) 603 return true; 604 605 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 606 &F.getEntryBlock() != BB) 607 return false; 608 609 // Do not instrument full dominators, or full post-dominators with multiple 610 // predecessors. 611 return !isFullDominator(BB, DT) 612 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 613 } 614 615 616 // Returns true iff From->To is a backedge. 617 // A twist here is that we treat From->To as a backedge if 618 // * To dominates From or 619 // * To->UniqueSuccessor dominates From 620 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 621 const DominatorTree *DT) { 622 if (DT->dominates(To, From)) 623 return true; 624 if (auto Next = To->getUniqueSuccessor()) 625 if (DT->dominates(Next, From)) 626 return true; 627 return false; 628 } 629 630 // Prunes uninteresting Cmp instrumentation: 631 // * CMP instructions that feed into loop backedge branch. 632 // 633 // Note that Cmp pruning is controlled by the same flag as the 634 // BB pruning. 635 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, 636 const SanitizerCoverageOptions &Options) { 637 if (!Options.NoPrune) 638 if (CMP->hasOneUse()) 639 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 640 for (BasicBlock *B : BR->successors()) 641 if (IsBackEdge(BR->getParent(), B, DT)) 642 return false; 643 return true; 644 } 645 646 void ModuleSanitizerCoverage::instrumentFunction( 647 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 648 if (F.empty()) 649 return; 650 if (F.getName().find(".module_ctor") != std::string::npos) 651 return; // Should not instrument sanitizer init functions. 652 if (F.getName().startswith("__sanitizer_")) 653 return; // Don't instrument __sanitizer_* callbacks. 654 // Don't touch available_externally functions, their actual body is elewhere. 655 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 656 return; 657 // Don't instrument MSVC CRT configuration helpers. They may run before normal 658 // initialization. 659 if (F.getName() == "__local_stdio_printf_options" || 660 F.getName() == "__local_stdio_scanf_options") 661 return; 662 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 663 return; 664 // Don't instrument functions using SEH for now. Splitting basic blocks like 665 // we do for coverage breaks WinEHPrepare. 666 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 667 if (F.hasPersonalityFn() && 668 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 669 return; 670 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 671 return; 672 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 673 return; 674 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 675 return; 676 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 677 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 678 SmallVector<Instruction *, 8> IndirCalls; 679 SmallVector<BasicBlock *, 16> BlocksToInstrument; 680 SmallVector<Instruction *, 8> CmpTraceTargets; 681 SmallVector<Instruction *, 8> SwitchTraceTargets; 682 SmallVector<BinaryOperator *, 8> DivTraceTargets; 683 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 684 SmallVector<LoadInst *, 8> Loads; 685 SmallVector<StoreInst *, 8> Stores; 686 687 const DominatorTree *DT = DTCallback(F); 688 const PostDominatorTree *PDT = PDTCallback(F); 689 bool IsLeafFunc = true; 690 691 for (auto &BB : F) { 692 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 693 BlocksToInstrument.push_back(&BB); 694 for (auto &Inst : BB) { 695 if (Options.IndirectCalls) { 696 CallBase *CB = dyn_cast<CallBase>(&Inst); 697 if (CB && !CB->getCalledFunction()) 698 IndirCalls.push_back(&Inst); 699 } 700 if (Options.TraceCmp) { 701 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 702 if (IsInterestingCmp(CMP, DT, Options)) 703 CmpTraceTargets.push_back(&Inst); 704 if (isa<SwitchInst>(&Inst)) 705 SwitchTraceTargets.push_back(&Inst); 706 } 707 if (Options.TraceDiv) 708 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 709 if (BO->getOpcode() == Instruction::SDiv || 710 BO->getOpcode() == Instruction::UDiv) 711 DivTraceTargets.push_back(BO); 712 if (Options.TraceGep) 713 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 714 GepTraceTargets.push_back(GEP); 715 if (Options.TraceLoads) 716 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 717 Loads.push_back(LI); 718 if (Options.TraceStores) 719 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 720 Stores.push_back(SI); 721 if (Options.StackDepth) 722 if (isa<InvokeInst>(Inst) || 723 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 724 IsLeafFunc = false; 725 } 726 } 727 728 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 729 InjectCoverageForIndirectCalls(F, IndirCalls); 730 InjectTraceForCmp(F, CmpTraceTargets); 731 InjectTraceForSwitch(F, SwitchTraceTargets); 732 InjectTraceForDiv(F, DivTraceTargets); 733 InjectTraceForGep(F, GepTraceTargets); 734 InjectTraceForLoadsAndStores(F, Loads, Stores); 735 } 736 737 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 738 size_t NumElements, Function &F, Type *Ty, const char *Section) { 739 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 740 auto Array = new GlobalVariable( 741 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 742 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 743 744 if (TargetTriple.supportsCOMDAT() && 745 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 746 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 747 Array->setComdat(Comdat); 748 Array->setSection(getSectionName(Section)); 749 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize())); 750 751 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 752 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 753 // section(s) as a unit, so we conservatively retain all unconditionally in 754 // the compiler. 755 // 756 // With comdat (COFF/ELF), the linker can guarantee the associated sections 757 // will be retained or discarded as a unit, so llvm.compiler.used is 758 // sufficient. Otherwise, conservatively make all of them retained by the 759 // linker. 760 if (Array->hasComdat()) 761 GlobalsToAppendToCompilerUsed.push_back(Array); 762 else 763 GlobalsToAppendToUsed.push_back(Array); 764 765 return Array; 766 } 767 768 GlobalVariable * 769 ModuleSanitizerCoverage::CreatePCArray(Function &F, 770 ArrayRef<BasicBlock *> AllBlocks) { 771 size_t N = AllBlocks.size(); 772 assert(N); 773 SmallVector<Constant *, 32> PCs; 774 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 775 for (size_t i = 0; i < N; i++) { 776 if (&F.getEntryBlock() == AllBlocks[i]) { 777 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 778 PCs.push_back((Constant *)IRB.CreateIntToPtr( 779 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 780 } else { 781 PCs.push_back((Constant *)IRB.CreatePointerCast( 782 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 783 PCs.push_back((Constant *)IRB.CreateIntToPtr( 784 ConstantInt::get(IntptrTy, 0), IntptrPtrTy)); 785 } 786 } 787 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 788 SanCovPCsSectionName); 789 PCArray->setInitializer( 790 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 791 PCArray->setConstant(true); 792 793 return PCArray; 794 } 795 796 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 797 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 798 if (Options.TracePCGuard) 799 FunctionGuardArray = CreateFunctionLocalArrayInSection( 800 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 801 802 if (Options.Inline8bitCounters) 803 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 804 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 805 if (Options.InlineBoolFlag) 806 FunctionBoolArray = CreateFunctionLocalArrayInSection( 807 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 808 809 if (Options.PCTable) 810 FunctionPCsArray = CreatePCArray(F, AllBlocks); 811 } 812 813 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 814 ArrayRef<BasicBlock *> AllBlocks, 815 bool IsLeafFunc) { 816 if (AllBlocks.empty()) return false; 817 CreateFunctionLocalArrays(F, AllBlocks); 818 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 819 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 820 return true; 821 } 822 823 // On every indirect call we call a run-time function 824 // __sanitizer_cov_indir_call* with two parameters: 825 // - callee address, 826 // - global cache array that contains CacheSize pointers (zero-initialized). 827 // The cache is used to speed up recording the caller-callee pairs. 828 // The address of the caller is passed implicitly via caller PC. 829 // CacheSize is encoded in the name of the run-time function. 830 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 831 Function &F, ArrayRef<Instruction *> IndirCalls) { 832 if (IndirCalls.empty()) 833 return; 834 assert(Options.TracePC || Options.TracePCGuard || 835 Options.Inline8bitCounters || Options.InlineBoolFlag); 836 for (auto I : IndirCalls) { 837 IRBuilder<> IRB(I); 838 CallBase &CB = cast<CallBase>(*I); 839 Value *Callee = CB.getCalledOperand(); 840 if (isa<InlineAsm>(Callee)) 841 continue; 842 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 843 } 844 } 845 846 // For every switch statement we insert a call: 847 // __sanitizer_cov_trace_switch(CondValue, 848 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 849 850 void ModuleSanitizerCoverage::InjectTraceForSwitch( 851 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 852 for (auto I : SwitchTraceTargets) { 853 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 854 IRBuilder<> IRB(I); 855 SmallVector<Constant *, 16> Initializers; 856 Value *Cond = SI->getCondition(); 857 if (Cond->getType()->getScalarSizeInBits() > 858 Int64Ty->getScalarSizeInBits()) 859 continue; 860 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 861 Initializers.push_back( 862 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 863 if (Cond->getType()->getScalarSizeInBits() < 864 Int64Ty->getScalarSizeInBits()) 865 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 866 for (auto It : SI->cases()) { 867 Constant *C = It.getCaseValue(); 868 if (C->getType()->getScalarSizeInBits() < 869 Int64Ty->getScalarSizeInBits()) 870 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 871 Initializers.push_back(C); 872 } 873 llvm::sort(drop_begin(Initializers, 2), 874 [](const Constant *A, const Constant *B) { 875 return cast<ConstantInt>(A)->getLimitedValue() < 876 cast<ConstantInt>(B)->getLimitedValue(); 877 }); 878 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 879 GlobalVariable *GV = new GlobalVariable( 880 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 881 ConstantArray::get(ArrayOfInt64Ty, Initializers), 882 "__sancov_gen_cov_switch_values"); 883 IRB.CreateCall(SanCovTraceSwitchFunction, 884 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 885 } 886 } 887 } 888 889 void ModuleSanitizerCoverage::InjectTraceForDiv( 890 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 891 for (auto BO : DivTraceTargets) { 892 IRBuilder<> IRB(BO); 893 Value *A1 = BO->getOperand(1); 894 if (isa<ConstantInt>(A1)) continue; 895 if (!A1->getType()->isIntegerTy()) 896 continue; 897 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 898 int CallbackIdx = TypeSize == 32 ? 0 : 899 TypeSize == 64 ? 1 : -1; 900 if (CallbackIdx < 0) continue; 901 auto Ty = Type::getIntNTy(*C, TypeSize); 902 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 903 {IRB.CreateIntCast(A1, Ty, true)}); 904 } 905 } 906 907 void ModuleSanitizerCoverage::InjectTraceForGep( 908 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 909 for (auto GEP : GepTraceTargets) { 910 IRBuilder<> IRB(GEP); 911 for (Use &Idx : GEP->indices()) 912 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 913 IRB.CreateCall(SanCovTraceGepFunction, 914 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 915 } 916 } 917 918 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 919 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 920 auto CallbackIdx = [&](Type *ElementTy) -> int { 921 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 922 return TypeSize == 8 ? 0 923 : TypeSize == 16 ? 1 924 : TypeSize == 32 ? 2 925 : TypeSize == 64 ? 3 926 : TypeSize == 128 ? 4 927 : -1; 928 }; 929 Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy, 930 Int128PtrTy}; 931 for (auto LI : Loads) { 932 IRBuilder<> IRB(LI); 933 auto Ptr = LI->getPointerOperand(); 934 int Idx = CallbackIdx(LI->getType()); 935 if (Idx < 0) 936 continue; 937 IRB.CreateCall(SanCovLoadFunction[Idx], 938 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 939 } 940 for (auto SI : Stores) { 941 IRBuilder<> IRB(SI); 942 auto Ptr = SI->getPointerOperand(); 943 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 944 if (Idx < 0) 945 continue; 946 IRB.CreateCall(SanCovStoreFunction[Idx], 947 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 948 } 949 } 950 951 void ModuleSanitizerCoverage::InjectTraceForCmp( 952 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 953 for (auto I : CmpTraceTargets) { 954 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 955 IRBuilder<> IRB(ICMP); 956 Value *A0 = ICMP->getOperand(0); 957 Value *A1 = ICMP->getOperand(1); 958 if (!A0->getType()->isIntegerTy()) 959 continue; 960 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 961 int CallbackIdx = TypeSize == 8 ? 0 : 962 TypeSize == 16 ? 1 : 963 TypeSize == 32 ? 2 : 964 TypeSize == 64 ? 3 : -1; 965 if (CallbackIdx < 0) continue; 966 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 967 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 968 bool FirstIsConst = isa<ConstantInt>(A0); 969 bool SecondIsConst = isa<ConstantInt>(A1); 970 // If both are const, then we don't need such a comparison. 971 if (FirstIsConst && SecondIsConst) continue; 972 // If only one is const, then make it the first callback argument. 973 if (FirstIsConst || SecondIsConst) { 974 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 975 if (SecondIsConst) 976 std::swap(A0, A1); 977 } 978 979 auto Ty = Type::getIntNTy(*C, TypeSize); 980 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 981 IRB.CreateIntCast(A1, Ty, true)}); 982 } 983 } 984 } 985 986 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 987 size_t Idx, 988 bool IsLeafFunc) { 989 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 990 bool IsEntryBB = &BB == &F.getEntryBlock(); 991 DebugLoc EntryLoc; 992 if (IsEntryBB) { 993 if (auto SP = F.getSubprogram()) 994 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 995 // Keep static allocas and llvm.localescape calls in the entry block. Even 996 // if we aren't splitting the block, it's nice for allocas to be before 997 // calls. 998 IP = PrepareToSplitEntryBlock(BB, IP); 999 } else { 1000 EntryLoc = IP->getDebugLoc(); 1001 if (!EntryLoc) 1002 if (auto *SP = F.getSubprogram()) 1003 EntryLoc = DILocation::get(SP->getContext(), 0, 0, SP); 1004 } 1005 1006 IRBuilder<> IRB(&*IP); 1007 IRB.SetCurrentDebugLocation(EntryLoc); 1008 if (Options.TracePC) { 1009 IRB.CreateCall(SanCovTracePC) 1010 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 1011 } 1012 if (Options.TracePCGuard) { 1013 auto GuardPtr = IRB.CreateIntToPtr( 1014 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 1015 ConstantInt::get(IntptrTy, Idx * 4)), 1016 Int32PtrTy); 1017 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 1018 } 1019 if (Options.Inline8bitCounters) { 1020 auto CounterPtr = IRB.CreateGEP( 1021 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 1022 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1023 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 1024 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 1025 auto Store = IRB.CreateStore(Inc, CounterPtr); 1026 SetNoSanitizeMetadata(Load); 1027 SetNoSanitizeMetadata(Store); 1028 } 1029 if (Options.InlineBoolFlag) { 1030 auto FlagPtr = IRB.CreateGEP( 1031 FunctionBoolArray->getValueType(), FunctionBoolArray, 1032 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1033 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 1034 auto ThenTerm = 1035 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false); 1036 IRBuilder<> ThenIRB(ThenTerm); 1037 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 1038 SetNoSanitizeMetadata(Load); 1039 SetNoSanitizeMetadata(Store); 1040 } 1041 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 1042 // Check stack depth. If it's the deepest so far, record it. 1043 Module *M = F.getParent(); 1044 Function *GetFrameAddr = Intrinsic::getDeclaration( 1045 M, Intrinsic::frameaddress, 1046 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace())); 1047 auto FrameAddrPtr = 1048 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 1049 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1050 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1051 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1052 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 1053 IRBuilder<> ThenIRB(ThenTerm); 1054 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1055 SetNoSanitizeMetadata(LowestStack); 1056 SetNoSanitizeMetadata(Store); 1057 } 1058 } 1059 1060 std::string 1061 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1062 if (TargetTriple.isOSBinFormatCOFF()) { 1063 if (Section == SanCovCountersSectionName) 1064 return ".SCOV$CM"; 1065 if (Section == SanCovBoolFlagSectionName) 1066 return ".SCOV$BM"; 1067 if (Section == SanCovPCsSectionName) 1068 return ".SCOVP$M"; 1069 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1070 } 1071 if (TargetTriple.isOSBinFormatMachO()) 1072 return "__DATA,__" + Section; 1073 return "__" + Section; 1074 } 1075 1076 std::string 1077 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1078 if (TargetTriple.isOSBinFormatMachO()) 1079 return "\1section$start$__DATA$__" + Section; 1080 return "__start___" + Section; 1081 } 1082 1083 std::string 1084 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1085 if (TargetTriple.isOSBinFormatMachO()) 1086 return "\1section$end$__DATA$__" + Section; 1087 return "__stop___" + Section; 1088 } 1089 1090 char ModuleSanitizerCoverageLegacyPass::ID = 0; 1091 INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov", 1092 "Pass for instrumenting coverage on functions", false, 1093 false) 1094 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 1095 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass) 1096 INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov", 1097 "Pass for instrumenting coverage on functions", false, 1098 false) 1099 ModulePass *llvm::createModuleSanitizerCoverageLegacyPassPass( 1100 const SanitizerCoverageOptions &Options, 1101 const std::vector<std::string> &AllowlistFiles, 1102 const std::vector<std::string> &BlocklistFiles) { 1103 return new ModuleSanitizerCoverageLegacyPass(Options, AllowlistFiles, 1104 BlocklistFiles); 1105 } 1106