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 (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 635 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 636 SmallVector<Instruction *, 8> IndirCalls; 637 SmallVector<BasicBlock *, 16> BlocksToInstrument; 638 SmallVector<Instruction *, 8> CmpTraceTargets; 639 SmallVector<Instruction *, 8> SwitchTraceTargets; 640 SmallVector<BinaryOperator *, 8> DivTraceTargets; 641 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 642 SmallVector<LoadInst *, 8> Loads; 643 SmallVector<StoreInst *, 8> Stores; 644 645 const DominatorTree &DT = DTCallback(F); 646 const PostDominatorTree &PDT = PDTCallback(F); 647 bool IsLeafFunc = true; 648 649 for (auto &BB : F) { 650 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 651 BlocksToInstrument.push_back(&BB); 652 for (auto &Inst : BB) { 653 if (Options.IndirectCalls) { 654 CallBase *CB = dyn_cast<CallBase>(&Inst); 655 if (CB && CB->isIndirectCall()) 656 IndirCalls.push_back(&Inst); 657 } 658 if (Options.TraceCmp) { 659 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 660 if (IsInterestingCmp(CMP, DT, Options)) 661 CmpTraceTargets.push_back(&Inst); 662 if (isa<SwitchInst>(&Inst)) 663 SwitchTraceTargets.push_back(&Inst); 664 } 665 if (Options.TraceDiv) 666 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 667 if (BO->getOpcode() == Instruction::SDiv || 668 BO->getOpcode() == Instruction::UDiv) 669 DivTraceTargets.push_back(BO); 670 if (Options.TraceGep) 671 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 672 GepTraceTargets.push_back(GEP); 673 if (Options.TraceLoads) 674 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 675 Loads.push_back(LI); 676 if (Options.TraceStores) 677 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 678 Stores.push_back(SI); 679 if (Options.StackDepth) 680 if (isa<InvokeInst>(Inst) || 681 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 682 IsLeafFunc = false; 683 } 684 } 685 686 if (Options.CollectControlFlow) 687 createFunctionControlFlow(F); 688 689 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 690 InjectCoverageForIndirectCalls(F, IndirCalls); 691 InjectTraceForCmp(F, CmpTraceTargets); 692 InjectTraceForSwitch(F, SwitchTraceTargets); 693 InjectTraceForDiv(F, DivTraceTargets); 694 InjectTraceForGep(F, GepTraceTargets); 695 InjectTraceForLoadsAndStores(F, Loads, Stores); 696 } 697 698 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 699 size_t NumElements, Function &F, Type *Ty, const char *Section) { 700 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 701 auto Array = new GlobalVariable( 702 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 703 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 704 705 if (TargetTriple.supportsCOMDAT() && 706 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 707 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 708 Array->setComdat(Comdat); 709 Array->setSection(getSectionName(Section)); 710 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue())); 711 712 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 713 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 714 // section(s) as a unit, so we conservatively retain all unconditionally in 715 // the compiler. 716 // 717 // With comdat (COFF/ELF), the linker can guarantee the associated sections 718 // will be retained or discarded as a unit, so llvm.compiler.used is 719 // sufficient. Otherwise, conservatively make all of them retained by the 720 // linker. 721 if (Array->hasComdat()) 722 GlobalsToAppendToCompilerUsed.push_back(Array); 723 else 724 GlobalsToAppendToUsed.push_back(Array); 725 726 return Array; 727 } 728 729 GlobalVariable * 730 ModuleSanitizerCoverage::CreatePCArray(Function &F, 731 ArrayRef<BasicBlock *> AllBlocks) { 732 size_t N = AllBlocks.size(); 733 assert(N); 734 SmallVector<Constant *, 32> PCs; 735 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 736 for (size_t i = 0; i < N; i++) { 737 if (&F.getEntryBlock() == AllBlocks[i]) { 738 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 739 PCs.push_back((Constant *)IRB.CreateIntToPtr( 740 ConstantInt::get(IntptrTy, 1), PtrTy)); 741 } else { 742 PCs.push_back((Constant *)IRB.CreatePointerCast( 743 BlockAddress::get(AllBlocks[i]), PtrTy)); 744 PCs.push_back(Constant::getNullValue(PtrTy)); 745 } 746 } 747 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, PtrTy, 748 SanCovPCsSectionName); 749 PCArray->setInitializer( 750 ConstantArray::get(ArrayType::get(PtrTy, N * 2), PCs)); 751 PCArray->setConstant(true); 752 753 return PCArray; 754 } 755 756 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 757 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 758 if (Options.TracePCGuard) 759 FunctionGuardArray = CreateFunctionLocalArrayInSection( 760 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 761 762 if (Options.Inline8bitCounters) 763 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 764 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 765 if (Options.InlineBoolFlag) 766 FunctionBoolArray = CreateFunctionLocalArrayInSection( 767 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 768 769 if (Options.PCTable) 770 FunctionPCsArray = CreatePCArray(F, AllBlocks); 771 } 772 773 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 774 ArrayRef<BasicBlock *> AllBlocks, 775 bool IsLeafFunc) { 776 if (AllBlocks.empty()) return false; 777 CreateFunctionLocalArrays(F, AllBlocks); 778 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 779 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 780 return true; 781 } 782 783 // On every indirect call we call a run-time function 784 // __sanitizer_cov_indir_call* with two parameters: 785 // - callee address, 786 // - global cache array that contains CacheSize pointers (zero-initialized). 787 // The cache is used to speed up recording the caller-callee pairs. 788 // The address of the caller is passed implicitly via caller PC. 789 // CacheSize is encoded in the name of the run-time function. 790 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 791 Function &F, ArrayRef<Instruction *> IndirCalls) { 792 if (IndirCalls.empty()) 793 return; 794 assert(Options.TracePC || Options.TracePCGuard || 795 Options.Inline8bitCounters || Options.InlineBoolFlag); 796 for (auto *I : IndirCalls) { 797 InstrumentationIRBuilder IRB(I); 798 CallBase &CB = cast<CallBase>(*I); 799 Value *Callee = CB.getCalledOperand(); 800 if (isa<InlineAsm>(Callee)) 801 continue; 802 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 803 } 804 } 805 806 // For every switch statement we insert a call: 807 // __sanitizer_cov_trace_switch(CondValue, 808 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 809 810 void ModuleSanitizerCoverage::InjectTraceForSwitch( 811 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 812 for (auto *I : SwitchTraceTargets) { 813 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 814 InstrumentationIRBuilder IRB(I); 815 SmallVector<Constant *, 16> Initializers; 816 Value *Cond = SI->getCondition(); 817 if (Cond->getType()->getScalarSizeInBits() > 818 Int64Ty->getScalarSizeInBits()) 819 continue; 820 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 821 Initializers.push_back( 822 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 823 if (Cond->getType()->getScalarSizeInBits() < 824 Int64Ty->getScalarSizeInBits()) 825 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 826 for (auto It : SI->cases()) { 827 ConstantInt *C = It.getCaseValue(); 828 if (C->getType()->getScalarSizeInBits() < 64) 829 C = ConstantInt::get(C->getContext(), C->getValue().zext(64)); 830 Initializers.push_back(C); 831 } 832 llvm::sort(drop_begin(Initializers, 2), 833 [](const Constant *A, const Constant *B) { 834 return cast<ConstantInt>(A)->getLimitedValue() < 835 cast<ConstantInt>(B)->getLimitedValue(); 836 }); 837 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 838 GlobalVariable *GV = new GlobalVariable( 839 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 840 ConstantArray::get(ArrayOfInt64Ty, Initializers), 841 "__sancov_gen_cov_switch_values"); 842 IRB.CreateCall(SanCovTraceSwitchFunction, {Cond, GV}); 843 } 844 } 845 } 846 847 void ModuleSanitizerCoverage::InjectTraceForDiv( 848 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 849 for (auto *BO : DivTraceTargets) { 850 InstrumentationIRBuilder IRB(BO); 851 Value *A1 = BO->getOperand(1); 852 if (isa<ConstantInt>(A1)) continue; 853 if (!A1->getType()->isIntegerTy()) 854 continue; 855 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 856 int CallbackIdx = TypeSize == 32 ? 0 : 857 TypeSize == 64 ? 1 : -1; 858 if (CallbackIdx < 0) continue; 859 auto Ty = Type::getIntNTy(*C, TypeSize); 860 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 861 {IRB.CreateIntCast(A1, Ty, true)}); 862 } 863 } 864 865 void ModuleSanitizerCoverage::InjectTraceForGep( 866 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 867 for (auto *GEP : GepTraceTargets) { 868 InstrumentationIRBuilder IRB(GEP); 869 for (Use &Idx : GEP->indices()) 870 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 871 IRB.CreateCall(SanCovTraceGepFunction, 872 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 873 } 874 } 875 876 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 877 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 878 auto CallbackIdx = [&](Type *ElementTy) -> int { 879 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 880 return TypeSize == 8 ? 0 881 : TypeSize == 16 ? 1 882 : TypeSize == 32 ? 2 883 : TypeSize == 64 ? 3 884 : TypeSize == 128 ? 4 885 : -1; 886 }; 887 for (auto *LI : Loads) { 888 InstrumentationIRBuilder IRB(LI); 889 auto Ptr = LI->getPointerOperand(); 890 int Idx = CallbackIdx(LI->getType()); 891 if (Idx < 0) 892 continue; 893 IRB.CreateCall(SanCovLoadFunction[Idx], Ptr); 894 } 895 for (auto *SI : Stores) { 896 InstrumentationIRBuilder IRB(SI); 897 auto Ptr = SI->getPointerOperand(); 898 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 899 if (Idx < 0) 900 continue; 901 IRB.CreateCall(SanCovStoreFunction[Idx], Ptr); 902 } 903 } 904 905 void ModuleSanitizerCoverage::InjectTraceForCmp( 906 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 907 for (auto *I : CmpTraceTargets) { 908 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 909 InstrumentationIRBuilder IRB(ICMP); 910 Value *A0 = ICMP->getOperand(0); 911 Value *A1 = ICMP->getOperand(1); 912 if (!A0->getType()->isIntegerTy()) 913 continue; 914 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 915 int CallbackIdx = TypeSize == 8 ? 0 : 916 TypeSize == 16 ? 1 : 917 TypeSize == 32 ? 2 : 918 TypeSize == 64 ? 3 : -1; 919 if (CallbackIdx < 0) continue; 920 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 921 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 922 bool FirstIsConst = isa<ConstantInt>(A0); 923 bool SecondIsConst = isa<ConstantInt>(A1); 924 // If both are const, then we don't need such a comparison. 925 if (FirstIsConst && SecondIsConst) continue; 926 // If only one is const, then make it the first callback argument. 927 if (FirstIsConst || SecondIsConst) { 928 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 929 if (SecondIsConst) 930 std::swap(A0, A1); 931 } 932 933 auto Ty = Type::getIntNTy(*C, TypeSize); 934 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 935 IRB.CreateIntCast(A1, Ty, true)}); 936 } 937 } 938 } 939 940 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 941 size_t Idx, 942 bool IsLeafFunc) { 943 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 944 bool IsEntryBB = &BB == &F.getEntryBlock(); 945 DebugLoc EntryLoc; 946 if (IsEntryBB) { 947 if (auto SP = F.getSubprogram()) 948 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 949 // Keep static allocas and llvm.localescape calls in the entry block. Even 950 // if we aren't splitting the block, it's nice for allocas to be before 951 // calls. 952 IP = PrepareToSplitEntryBlock(BB, IP); 953 } 954 955 InstrumentationIRBuilder IRB(&*IP); 956 if (EntryLoc) 957 IRB.SetCurrentDebugLocation(EntryLoc); 958 if (Options.TracePC) { 959 IRB.CreateCall(SanCovTracePC) 960 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 961 } 962 if (Options.TracePCGuard) { 963 auto GuardPtr = IRB.CreateIntToPtr( 964 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 965 ConstantInt::get(IntptrTy, Idx * 4)), 966 PtrTy); 967 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 968 } 969 if (Options.Inline8bitCounters) { 970 auto CounterPtr = IRB.CreateGEP( 971 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 972 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 973 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 974 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 975 auto Store = IRB.CreateStore(Inc, CounterPtr); 976 Load->setNoSanitizeMetadata(); 977 Store->setNoSanitizeMetadata(); 978 } 979 if (Options.InlineBoolFlag) { 980 auto FlagPtr = IRB.CreateGEP( 981 FunctionBoolArray->getValueType(), FunctionBoolArray, 982 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 983 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 984 auto ThenTerm = SplitBlockAndInsertIfThen( 985 IRB.CreateIsNull(Load), &*IP, false, 986 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 987 IRBuilder<> ThenIRB(ThenTerm); 988 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 989 Load->setNoSanitizeMetadata(); 990 Store->setNoSanitizeMetadata(); 991 } 992 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 993 // Check stack depth. If it's the deepest so far, record it. 994 Module *M = F.getParent(); 995 Function *GetFrameAddr = Intrinsic::getDeclaration( 996 M, Intrinsic::frameaddress, 997 IRB.getPtrTy(M->getDataLayout().getAllocaAddrSpace())); 998 auto FrameAddrPtr = 999 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 1000 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1001 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1002 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1003 auto ThenTerm = SplitBlockAndInsertIfThen( 1004 IsStackLower, &*IP, false, 1005 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 1006 IRBuilder<> ThenIRB(ThenTerm); 1007 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1008 LowestStack->setNoSanitizeMetadata(); 1009 Store->setNoSanitizeMetadata(); 1010 } 1011 } 1012 1013 std::string 1014 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1015 if (TargetTriple.isOSBinFormatCOFF()) { 1016 if (Section == SanCovCountersSectionName) 1017 return ".SCOV$CM"; 1018 if (Section == SanCovBoolFlagSectionName) 1019 return ".SCOV$BM"; 1020 if (Section == SanCovPCsSectionName) 1021 return ".SCOVP$M"; 1022 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1023 } 1024 if (TargetTriple.isOSBinFormatMachO()) 1025 return "__DATA,__" + Section; 1026 return "__" + Section; 1027 } 1028 1029 std::string 1030 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1031 if (TargetTriple.isOSBinFormatMachO()) 1032 return "\1section$start$__DATA$__" + Section; 1033 return "__start___" + Section; 1034 } 1035 1036 std::string 1037 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1038 if (TargetTriple.isOSBinFormatMachO()) 1039 return "\1section$end$__DATA$__" + Section; 1040 return "__stop___" + Section; 1041 } 1042 1043 void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) { 1044 SmallVector<Constant *, 32> CFs; 1045 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 1046 1047 for (auto &BB : F) { 1048 // blockaddress can not be used on function's entry block. 1049 if (&BB == &F.getEntryBlock()) 1050 CFs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 1051 else 1052 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(&BB), 1053 PtrTy)); 1054 1055 for (auto SuccBB : successors(&BB)) { 1056 assert(SuccBB != &F.getEntryBlock()); 1057 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(SuccBB), 1058 PtrTy)); 1059 } 1060 1061 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1062 1063 for (auto &Inst : BB) { 1064 if (CallBase *CB = dyn_cast<CallBase>(&Inst)) { 1065 if (CB->isIndirectCall()) { 1066 // TODO(navidem): handle indirect calls, for now mark its existence. 1067 CFs.push_back((Constant *)IRB.CreateIntToPtr( 1068 ConstantInt::get(IntptrTy, -1), PtrTy)); 1069 } else { 1070 auto CalledF = CB->getCalledFunction(); 1071 if (CalledF && !CalledF->isIntrinsic()) 1072 CFs.push_back( 1073 (Constant *)IRB.CreatePointerCast(CalledF, PtrTy)); 1074 } 1075 } 1076 } 1077 1078 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1079 } 1080 1081 FunctionCFsArray = CreateFunctionLocalArrayInSection( 1082 CFs.size(), F, PtrTy, SanCovCFsSectionName); 1083 FunctionCFsArray->setInitializer( 1084 ConstantArray::get(ArrayType::get(PtrTy, CFs.size()), CFs)); 1085 FunctionCFsArray->setConstant(true); 1086 } 1087