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