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