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