1 //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Coverage instrumentation done on LLVM IR level, works with Sanitizers. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h" 14 #include "llvm/ADT/ArrayRef.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/Analysis/GlobalsModRef.h" 17 #include "llvm/Analysis/PostDominators.h" 18 #include "llvm/IR/Constant.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/IR/Dominators.h" 21 #include "llvm/IR/EHPersonalities.h" 22 #include "llvm/IR/Function.h" 23 #include "llvm/IR/GlobalVariable.h" 24 #include "llvm/IR/IRBuilder.h" 25 #include "llvm/IR/IntrinsicInst.h" 26 #include "llvm/IR/Intrinsics.h" 27 #include "llvm/IR/LLVMContext.h" 28 #include "llvm/IR/MDBuilder.h" 29 #include "llvm/IR/Module.h" 30 #include "llvm/IR/Type.h" 31 #include "llvm/Support/CommandLine.h" 32 #include "llvm/Support/SpecialCaseList.h" 33 #include "llvm/Support/VirtualFileSystem.h" 34 #include "llvm/TargetParser/Triple.h" 35 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 36 #include "llvm/Transforms/Utils/ModuleUtils.h" 37 38 using namespace llvm; 39 40 #define DEBUG_TYPE "sancov" 41 42 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 43 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 44 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 45 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 46 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 47 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 48 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 49 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 50 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 51 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 52 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 53 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 54 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 55 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 56 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 57 const char SanCovStore1[] = "__sanitizer_cov_store1"; 58 const char SanCovStore2[] = "__sanitizer_cov_store2"; 59 const char SanCovStore4[] = "__sanitizer_cov_store4"; 60 const char SanCovStore8[] = "__sanitizer_cov_store8"; 61 const char SanCovStore16[] = "__sanitizer_cov_store16"; 62 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 63 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 64 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 65 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 66 const char SanCovModuleCtorTracePcGuardName[] = 67 "sancov.module_ctor_trace_pc_guard"; 68 const char SanCovModuleCtor8bitCountersName[] = 69 "sancov.module_ctor_8bit_counters"; 70 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 71 static const uint64_t SanCtorAndDtorPriority = 2; 72 73 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 74 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 75 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 76 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 77 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 78 const char SanCovCFsInitName[] = "__sanitizer_cov_cfs_init"; 79 80 const char SanCovGuardsSectionName[] = "sancov_guards"; 81 const char SanCovCountersSectionName[] = "sancov_cntrs"; 82 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 83 const char SanCovPCsSectionName[] = "sancov_pcs"; 84 const char SanCovCFsSectionName[] = "sancov_cfs"; 85 86 const char SanCovLowestStackName[] = "__sancov_lowest_stack"; 87 88 static cl::opt<int> ClCoverageLevel( 89 "sanitizer-coverage-level", 90 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 91 "3: all blocks and critical edges"), 92 cl::Hidden, cl::init(0)); 93 94 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 95 cl::desc("Experimental pc tracing"), cl::Hidden, 96 cl::init(false)); 97 98 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 99 cl::desc("pc tracing with a guard"), 100 cl::Hidden, cl::init(false)); 101 102 // If true, we create a global variable that contains PCs of all instrumented 103 // BBs, put this global into a named section, and pass this section's bounds 104 // to __sanitizer_cov_pcs_init. 105 // This way the coverage instrumentation does not need to acquire the PCs 106 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 107 // inline-bool-flag. 108 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 109 cl::desc("create a static PC table"), 110 cl::Hidden, cl::init(false)); 111 112 static cl::opt<bool> 113 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 114 cl::desc("increments 8-bit counter for every edge"), 115 cl::Hidden, cl::init(false)); 116 117 static cl::opt<bool> 118 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 119 cl::desc("sets a boolean flag for every edge"), cl::Hidden, 120 cl::init(false)); 121 122 static cl::opt<bool> 123 ClCMPTracing("sanitizer-coverage-trace-compares", 124 cl::desc("Tracing of CMP and similar instructions"), 125 cl::Hidden, cl::init(false)); 126 127 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 128 cl::desc("Tracing of DIV instructions"), 129 cl::Hidden, cl::init(false)); 130 131 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads", 132 cl::desc("Tracing of load instructions"), 133 cl::Hidden, cl::init(false)); 134 135 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 136 cl::desc("Tracing of store instructions"), 137 cl::Hidden, cl::init(false)); 138 139 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 140 cl::desc("Tracing of GEP instructions"), 141 cl::Hidden, cl::init(false)); 142 143 static cl::opt<bool> 144 ClPruneBlocks("sanitizer-coverage-prune-blocks", 145 cl::desc("Reduce the number of instrumented blocks"), 146 cl::Hidden, cl::init(true)); 147 148 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 149 cl::desc("max stack depth tracing"), 150 cl::Hidden, cl::init(false)); 151 152 static cl::opt<bool> 153 ClCollectCF("sanitizer-coverage-control-flow", 154 cl::desc("collect control flow for each function"), cl::Hidden, 155 cl::init(false)); 156 157 namespace { 158 159 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 160 SanitizerCoverageOptions Res; 161 switch (LegacyCoverageLevel) { 162 case 0: 163 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 164 break; 165 case 1: 166 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 167 break; 168 case 2: 169 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 170 break; 171 case 3: 172 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 173 break; 174 case 4: 175 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 176 Res.IndirectCalls = true; 177 break; 178 } 179 return Res; 180 } 181 182 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 183 // Sets CoverageType and IndirectCalls. 184 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 185 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 186 Options.IndirectCalls |= CLOpts.IndirectCalls; 187 Options.TraceCmp |= ClCMPTracing; 188 Options.TraceDiv |= ClDIVTracing; 189 Options.TraceGep |= ClGEPTracing; 190 Options.TracePC |= ClTracePC; 191 Options.TracePCGuard |= ClTracePCGuard; 192 Options.Inline8bitCounters |= ClInline8bitCounters; 193 Options.InlineBoolFlag |= ClInlineBoolFlag; 194 Options.PCTable |= ClCreatePCTable; 195 Options.NoPrune |= !ClPruneBlocks; 196 Options.StackDepth |= ClStackDepth; 197 Options.TraceLoads |= ClLoadTracing; 198 Options.TraceStores |= ClStoreTracing; 199 if (!Options.TracePCGuard && !Options.TracePC && 200 !Options.Inline8bitCounters && !Options.StackDepth && 201 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 202 Options.TracePCGuard = true; // TracePCGuard is default. 203 Options.CollectControlFlow |= ClCollectCF; 204 return Options; 205 } 206 207 class ModuleSanitizerCoverage { 208 public: 209 using DomTreeCallback = function_ref<const DominatorTree &(Function &F)>; 210 using PostDomTreeCallback = 211 function_ref<const PostDominatorTree &(Function &F)>; 212 ModuleSanitizerCoverage( 213 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 214 const SpecialCaseList *Allowlist = nullptr, 215 const SpecialCaseList *Blocklist = nullptr) 216 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 217 Blocklist(Blocklist) {} 218 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 219 PostDomTreeCallback PDTCallback); 220 221 private: 222 void createFunctionControlFlow(Function &F); 223 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 224 PostDomTreeCallback PDTCallback); 225 void InjectCoverageForIndirectCalls(Function &F, 226 ArrayRef<Instruction *> IndirCalls); 227 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 228 void InjectTraceForDiv(Function &F, 229 ArrayRef<BinaryOperator *> DivTraceTargets); 230 void InjectTraceForGep(Function &F, 231 ArrayRef<GetElementPtrInst *> GepTraceTargets); 232 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 233 ArrayRef<StoreInst *> Stores); 234 void InjectTraceForSwitch(Function &F, 235 ArrayRef<Instruction *> SwitchTraceTargets); 236 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 237 bool IsLeafFunc = true); 238 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 239 Function &F, Type *Ty, 240 const char *Section); 241 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 242 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 243 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 244 bool IsLeafFunc = true); 245 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 246 const char *InitFunctionName, Type *Ty, 247 const char *Section); 248 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 249 Type *Ty); 250 251 std::string getSectionName(const std::string &Section) const; 252 std::string getSectionStart(const std::string &Section) const; 253 std::string getSectionEnd(const std::string &Section) const; 254 FunctionCallee SanCovTracePCIndir; 255 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 256 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 257 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 258 std::array<FunctionCallee, 5> SanCovLoadFunction; 259 std::array<FunctionCallee, 5> SanCovStoreFunction; 260 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 261 FunctionCallee SanCovTraceGepFunction; 262 FunctionCallee SanCovTraceSwitchFunction; 263 GlobalVariable *SanCovLowestStack; 264 Type *PtrTy, *IntptrTy, *Int64Ty, *Int32Ty, *Int16Ty, *Int8Ty, *Int1Ty; 265 Module *CurModule; 266 std::string CurModuleUniqueId; 267 Triple TargetTriple; 268 LLVMContext *C; 269 const DataLayout *DL; 270 271 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 272 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 273 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 274 GlobalVariable *FunctionPCsArray; // for pc-table. 275 GlobalVariable *FunctionCFsArray; // for control flow table 276 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 277 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 278 279 SanitizerCoverageOptions Options; 280 281 const SpecialCaseList *Allowlist; 282 const SpecialCaseList *Blocklist; 283 }; 284 } // namespace 285 286 PreservedAnalyses SanitizerCoveragePass::run(Module &M, 287 ModuleAnalysisManager &MAM) { 288 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 289 Blocklist.get()); 290 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 291 auto DTCallback = [&FAM](Function &F) -> const DominatorTree & { 292 return FAM.getResult<DominatorTreeAnalysis>(F); 293 }; 294 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree & { 295 return FAM.getResult<PostDominatorTreeAnalysis>(F); 296 }; 297 if (!ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 298 return PreservedAnalyses::all(); 299 300 PreservedAnalyses PA = PreservedAnalyses::none(); 301 // GlobalsAA is considered stateless and does not get invalidated unless 302 // explicitly invalidated; PreservedAnalyses::none() is not enough. Sanitizers 303 // make changes that require GlobalsAA to be invalidated. 304 PA.abandon<GlobalsAA>(); 305 return PA; 306 } 307 308 std::pair<Value *, Value *> 309 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 310 Type *Ty) { 311 // Use ExternalWeak so that if all sections are discarded due to section 312 // garbage collection, the linker will not report undefined symbol errors. 313 // Windows defines the start/stop symbols in compiler-rt so no need for 314 // ExternalWeak. 315 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 316 ? GlobalVariable::ExternalLinkage 317 : GlobalVariable::ExternalWeakLinkage; 318 GlobalVariable *SecStart = 319 new GlobalVariable(M, Ty, false, Linkage, nullptr, 320 getSectionStart(Section)); 321 SecStart->setVisibility(GlobalValue::HiddenVisibility); 322 GlobalVariable *SecEnd = 323 new GlobalVariable(M, Ty, false, Linkage, nullptr, 324 getSectionEnd(Section)); 325 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 326 IRBuilder<> IRB(M.getContext()); 327 if (!TargetTriple.isOSBinFormatCOFF()) 328 return std::make_pair(SecStart, SecEnd); 329 330 // Account for the fact that on windows-msvc __start_* symbols actually 331 // point to a uint64_t before the start of the array. 332 auto GEP = 333 IRB.CreatePtrAdd(SecStart, ConstantInt::get(IntptrTy, sizeof(uint64_t))); 334 return std::make_pair(GEP, SecEnd); 335 } 336 337 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 338 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 339 const char *Section) { 340 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 341 auto SecStart = SecStartEnd.first; 342 auto SecEnd = SecStartEnd.second; 343 Function *CtorFunc; 344 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 345 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 346 assert(CtorFunc->getName() == CtorName); 347 348 if (TargetTriple.supportsCOMDAT()) { 349 // Use comdat to dedup CtorFunc. 350 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 351 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 352 } else { 353 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 354 } 355 356 if (TargetTriple.isOSBinFormatCOFF()) { 357 // In COFF files, if the contructors are set as COMDAT (they are because 358 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 359 // functions and data) is used, the constructors get stripped. To prevent 360 // this, give the constructors weak ODR linkage and ensure the linker knows 361 // to include the sancov constructor. This way the linker can deduplicate 362 // the constructors but always leave one copy. 363 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 364 } 365 return CtorFunc; 366 } 367 368 bool ModuleSanitizerCoverage::instrumentModule( 369 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 370 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 371 return false; 372 if (Allowlist && 373 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 374 return false; 375 if (Blocklist && 376 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 377 return false; 378 C = &(M.getContext()); 379 DL = &M.getDataLayout(); 380 CurModule = &M; 381 CurModuleUniqueId = getUniqueModuleId(CurModule); 382 TargetTriple = Triple(M.getTargetTriple()); 383 FunctionGuardArray = nullptr; 384 Function8bitCounterArray = nullptr; 385 FunctionBoolArray = nullptr; 386 FunctionPCsArray = nullptr; 387 FunctionCFsArray = nullptr; 388 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 389 PtrTy = PointerType::getUnqual(*C); 390 Type *VoidTy = Type::getVoidTy(*C); 391 IRBuilder<> IRB(*C); 392 Int64Ty = IRB.getInt64Ty(); 393 Int32Ty = IRB.getInt32Ty(); 394 Int16Ty = IRB.getInt16Ty(); 395 Int8Ty = IRB.getInt8Ty(); 396 Int1Ty = IRB.getInt1Ty(); 397 398 SanCovTracePCIndir = 399 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 400 // Make sure smaller parameters are zero-extended to i64 if required by the 401 // target ABI. 402 AttributeList SanCovTraceCmpZeroExtAL; 403 SanCovTraceCmpZeroExtAL = 404 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 405 SanCovTraceCmpZeroExtAL = 406 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 407 408 SanCovTraceCmpFunction[0] = 409 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 410 IRB.getInt8Ty(), IRB.getInt8Ty()); 411 SanCovTraceCmpFunction[1] = 412 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 413 IRB.getInt16Ty(), IRB.getInt16Ty()); 414 SanCovTraceCmpFunction[2] = 415 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 416 IRB.getInt32Ty(), IRB.getInt32Ty()); 417 SanCovTraceCmpFunction[3] = 418 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 419 420 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 421 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 422 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 423 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 424 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 425 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 426 SanCovTraceConstCmpFunction[3] = 427 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 428 429 // Loads. 430 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, PtrTy); 431 SanCovLoadFunction[1] = 432 M.getOrInsertFunction(SanCovLoad2, VoidTy, PtrTy); 433 SanCovLoadFunction[2] = 434 M.getOrInsertFunction(SanCovLoad4, VoidTy, PtrTy); 435 SanCovLoadFunction[3] = 436 M.getOrInsertFunction(SanCovLoad8, VoidTy, PtrTy); 437 SanCovLoadFunction[4] = 438 M.getOrInsertFunction(SanCovLoad16, VoidTy, PtrTy); 439 // Stores. 440 SanCovStoreFunction[0] = 441 M.getOrInsertFunction(SanCovStore1, VoidTy, PtrTy); 442 SanCovStoreFunction[1] = 443 M.getOrInsertFunction(SanCovStore2, VoidTy, PtrTy); 444 SanCovStoreFunction[2] = 445 M.getOrInsertFunction(SanCovStore4, VoidTy, PtrTy); 446 SanCovStoreFunction[3] = 447 M.getOrInsertFunction(SanCovStore8, VoidTy, PtrTy); 448 SanCovStoreFunction[4] = 449 M.getOrInsertFunction(SanCovStore16, VoidTy, PtrTy); 450 451 { 452 AttributeList AL; 453 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 454 SanCovTraceDivFunction[0] = 455 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 456 } 457 SanCovTraceDivFunction[1] = 458 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 459 SanCovTraceGepFunction = 460 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 461 SanCovTraceSwitchFunction = 462 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, PtrTy); 463 464 Constant *SanCovLowestStackConstant = 465 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 466 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 467 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 468 C->emitError(StringRef("'") + SanCovLowestStackName + 469 "' should not be declared by the user"); 470 return true; 471 } 472 SanCovLowestStack->setThreadLocalMode( 473 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 474 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 475 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 476 477 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 478 SanCovTracePCGuard = 479 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, PtrTy); 480 481 for (auto &F : M) 482 instrumentFunction(F, DTCallback, PDTCallback); 483 484 Function *Ctor = nullptr; 485 486 if (FunctionGuardArray) 487 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 488 SanCovTracePCGuardInitName, Int32Ty, 489 SanCovGuardsSectionName); 490 if (Function8bitCounterArray) 491 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 492 SanCov8bitCountersInitName, Int8Ty, 493 SanCovCountersSectionName); 494 if (FunctionBoolArray) { 495 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 496 SanCovBoolFlagInitName, Int1Ty, 497 SanCovBoolFlagSectionName); 498 } 499 if (Ctor && Options.PCTable) { 500 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 501 FunctionCallee InitFunction = declareSanitizerInitFunction( 502 M, SanCovPCsInitName, {PtrTy, PtrTy}); 503 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 504 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 505 } 506 507 if (Ctor && Options.CollectControlFlow) { 508 auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrTy); 509 FunctionCallee InitFunction = declareSanitizerInitFunction( 510 M, SanCovCFsInitName, {PtrTy, PtrTy}); 511 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 512 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 513 } 514 515 appendToUsed(M, GlobalsToAppendToUsed); 516 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 517 return true; 518 } 519 520 // True if block has successors and it dominates all of them. 521 static bool isFullDominator(const BasicBlock *BB, const DominatorTree &DT) { 522 if (succ_empty(BB)) 523 return false; 524 525 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 526 return DT.dominates(BB, SUCC); 527 }); 528 } 529 530 // True if block has predecessors and it postdominates all of them. 531 static bool isFullPostDominator(const BasicBlock *BB, 532 const PostDominatorTree &PDT) { 533 if (pred_empty(BB)) 534 return false; 535 536 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 537 return PDT.dominates(BB, PRED); 538 }); 539 } 540 541 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 542 const DominatorTree &DT, 543 const PostDominatorTree &PDT, 544 const SanitizerCoverageOptions &Options) { 545 // Don't insert coverage for blocks containing nothing but unreachable: we 546 // will never call __sanitizer_cov() for them, so counting them in 547 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 548 // percentage. Also, unreachable instructions frequently have no debug 549 // locations. 550 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 551 return false; 552 553 // Don't insert coverage into blocks without a valid insertion point 554 // (catchswitch blocks). 555 if (BB->getFirstInsertionPt() == BB->end()) 556 return false; 557 558 if (Options.NoPrune || &F.getEntryBlock() == BB) 559 return true; 560 561 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 562 &F.getEntryBlock() != BB) 563 return false; 564 565 // Do not instrument full dominators, or full post-dominators with multiple 566 // predecessors. 567 return !isFullDominator(BB, DT) 568 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 569 } 570 571 // Returns true iff From->To is a backedge. 572 // A twist here is that we treat From->To as a backedge if 573 // * To dominates From or 574 // * To->UniqueSuccessor dominates From 575 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 576 const DominatorTree &DT) { 577 if (DT.dominates(To, From)) 578 return true; 579 if (auto Next = To->getUniqueSuccessor()) 580 if (DT.dominates(Next, From)) 581 return true; 582 return false; 583 } 584 585 // Prunes uninteresting Cmp instrumentation: 586 // * CMP instructions that feed into loop backedge branch. 587 // 588 // Note that Cmp pruning is controlled by the same flag as the 589 // BB pruning. 590 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree &DT, 591 const SanitizerCoverageOptions &Options) { 592 if (!Options.NoPrune) 593 if (CMP->hasOneUse()) 594 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 595 for (BasicBlock *B : BR->successors()) 596 if (IsBackEdge(BR->getParent(), B, DT)) 597 return false; 598 return true; 599 } 600 601 void ModuleSanitizerCoverage::instrumentFunction( 602 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 603 if (F.empty()) 604 return; 605 if (F.getName().contains(".module_ctor")) 606 return; // Should not instrument sanitizer init functions. 607 if (F.getName().starts_with("__sanitizer_")) 608 return; // Don't instrument __sanitizer_* callbacks. 609 // Don't touch available_externally functions, their actual body is elewhere. 610 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 611 return; 612 // Don't instrument MSVC CRT configuration helpers. They may run before normal 613 // initialization. 614 if (F.getName() == "__local_stdio_printf_options" || 615 F.getName() == "__local_stdio_scanf_options") 616 return; 617 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 618 return; 619 // Don't instrument functions using SEH for now. Splitting basic blocks like 620 // we do for coverage breaks WinEHPrepare. 621 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 622 if (F.hasPersonalityFn() && 623 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 624 return; 625 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 626 return; 627 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 628 return; 629 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 630 return; 631 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 632 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 633 SmallVector<Instruction *, 8> IndirCalls; 634 SmallVector<BasicBlock *, 16> BlocksToInstrument; 635 SmallVector<Instruction *, 8> CmpTraceTargets; 636 SmallVector<Instruction *, 8> SwitchTraceTargets; 637 SmallVector<BinaryOperator *, 8> DivTraceTargets; 638 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 639 SmallVector<LoadInst *, 8> Loads; 640 SmallVector<StoreInst *, 8> Stores; 641 642 const DominatorTree &DT = DTCallback(F); 643 const PostDominatorTree &PDT = PDTCallback(F); 644 bool IsLeafFunc = true; 645 646 for (auto &BB : F) { 647 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 648 BlocksToInstrument.push_back(&BB); 649 for (auto &Inst : BB) { 650 if (Options.IndirectCalls) { 651 CallBase *CB = dyn_cast<CallBase>(&Inst); 652 if (CB && CB->isIndirectCall()) 653 IndirCalls.push_back(&Inst); 654 } 655 if (Options.TraceCmp) { 656 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 657 if (IsInterestingCmp(CMP, DT, Options)) 658 CmpTraceTargets.push_back(&Inst); 659 if (isa<SwitchInst>(&Inst)) 660 SwitchTraceTargets.push_back(&Inst); 661 } 662 if (Options.TraceDiv) 663 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 664 if (BO->getOpcode() == Instruction::SDiv || 665 BO->getOpcode() == Instruction::UDiv) 666 DivTraceTargets.push_back(BO); 667 if (Options.TraceGep) 668 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 669 GepTraceTargets.push_back(GEP); 670 if (Options.TraceLoads) 671 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 672 Loads.push_back(LI); 673 if (Options.TraceStores) 674 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 675 Stores.push_back(SI); 676 if (Options.StackDepth) 677 if (isa<InvokeInst>(Inst) || 678 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 679 IsLeafFunc = false; 680 } 681 } 682 683 if (Options.CollectControlFlow) 684 createFunctionControlFlow(F); 685 686 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 687 InjectCoverageForIndirectCalls(F, IndirCalls); 688 InjectTraceForCmp(F, CmpTraceTargets); 689 InjectTraceForSwitch(F, SwitchTraceTargets); 690 InjectTraceForDiv(F, DivTraceTargets); 691 InjectTraceForGep(F, GepTraceTargets); 692 InjectTraceForLoadsAndStores(F, Loads, Stores); 693 } 694 695 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 696 size_t NumElements, Function &F, Type *Ty, const char *Section) { 697 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 698 auto Array = new GlobalVariable( 699 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 700 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 701 702 if (TargetTriple.supportsCOMDAT() && 703 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 704 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 705 Array->setComdat(Comdat); 706 Array->setSection(getSectionName(Section)); 707 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue())); 708 709 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 710 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 711 // section(s) as a unit, so we conservatively retain all unconditionally in 712 // the compiler. 713 // 714 // With comdat (COFF/ELF), the linker can guarantee the associated sections 715 // will be retained or discarded as a unit, so llvm.compiler.used is 716 // sufficient. Otherwise, conservatively make all of them retained by the 717 // linker. 718 if (Array->hasComdat()) 719 GlobalsToAppendToCompilerUsed.push_back(Array); 720 else 721 GlobalsToAppendToUsed.push_back(Array); 722 723 return Array; 724 } 725 726 GlobalVariable * 727 ModuleSanitizerCoverage::CreatePCArray(Function &F, 728 ArrayRef<BasicBlock *> AllBlocks) { 729 size_t N = AllBlocks.size(); 730 assert(N); 731 SmallVector<Constant *, 32> PCs; 732 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 733 for (size_t i = 0; i < N; i++) { 734 if (&F.getEntryBlock() == AllBlocks[i]) { 735 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 736 PCs.push_back((Constant *)IRB.CreateIntToPtr( 737 ConstantInt::get(IntptrTy, 1), PtrTy)); 738 } else { 739 PCs.push_back((Constant *)IRB.CreatePointerCast( 740 BlockAddress::get(AllBlocks[i]), PtrTy)); 741 PCs.push_back(Constant::getNullValue(PtrTy)); 742 } 743 } 744 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, PtrTy, 745 SanCovPCsSectionName); 746 PCArray->setInitializer( 747 ConstantArray::get(ArrayType::get(PtrTy, N * 2), PCs)); 748 PCArray->setConstant(true); 749 750 return PCArray; 751 } 752 753 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 754 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 755 if (Options.TracePCGuard) 756 FunctionGuardArray = CreateFunctionLocalArrayInSection( 757 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 758 759 if (Options.Inline8bitCounters) 760 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 761 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 762 if (Options.InlineBoolFlag) 763 FunctionBoolArray = CreateFunctionLocalArrayInSection( 764 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 765 766 if (Options.PCTable) 767 FunctionPCsArray = CreatePCArray(F, AllBlocks); 768 } 769 770 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 771 ArrayRef<BasicBlock *> AllBlocks, 772 bool IsLeafFunc) { 773 if (AllBlocks.empty()) return false; 774 CreateFunctionLocalArrays(F, AllBlocks); 775 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 776 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 777 return true; 778 } 779 780 // On every indirect call we call a run-time function 781 // __sanitizer_cov_indir_call* with two parameters: 782 // - callee address, 783 // - global cache array that contains CacheSize pointers (zero-initialized). 784 // The cache is used to speed up recording the caller-callee pairs. 785 // The address of the caller is passed implicitly via caller PC. 786 // CacheSize is encoded in the name of the run-time function. 787 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 788 Function &F, ArrayRef<Instruction *> IndirCalls) { 789 if (IndirCalls.empty()) 790 return; 791 assert(Options.TracePC || Options.TracePCGuard || 792 Options.Inline8bitCounters || Options.InlineBoolFlag); 793 for (auto *I : IndirCalls) { 794 InstrumentationIRBuilder IRB(I); 795 CallBase &CB = cast<CallBase>(*I); 796 Value *Callee = CB.getCalledOperand(); 797 if (isa<InlineAsm>(Callee)) 798 continue; 799 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 800 } 801 } 802 803 // For every switch statement we insert a call: 804 // __sanitizer_cov_trace_switch(CondValue, 805 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 806 807 void ModuleSanitizerCoverage::InjectTraceForSwitch( 808 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 809 for (auto *I : SwitchTraceTargets) { 810 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 811 InstrumentationIRBuilder IRB(I); 812 SmallVector<Constant *, 16> Initializers; 813 Value *Cond = SI->getCondition(); 814 if (Cond->getType()->getScalarSizeInBits() > 815 Int64Ty->getScalarSizeInBits()) 816 continue; 817 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 818 Initializers.push_back( 819 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 820 if (Cond->getType()->getScalarSizeInBits() < 821 Int64Ty->getScalarSizeInBits()) 822 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 823 for (auto It : SI->cases()) { 824 ConstantInt *C = It.getCaseValue(); 825 if (C->getType()->getScalarSizeInBits() < 64) 826 C = ConstantInt::get(C->getContext(), C->getValue().zext(64)); 827 Initializers.push_back(C); 828 } 829 llvm::sort(drop_begin(Initializers, 2), 830 [](const Constant *A, const Constant *B) { 831 return cast<ConstantInt>(A)->getLimitedValue() < 832 cast<ConstantInt>(B)->getLimitedValue(); 833 }); 834 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 835 GlobalVariable *GV = new GlobalVariable( 836 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 837 ConstantArray::get(ArrayOfInt64Ty, Initializers), 838 "__sancov_gen_cov_switch_values"); 839 IRB.CreateCall(SanCovTraceSwitchFunction, {Cond, GV}); 840 } 841 } 842 } 843 844 void ModuleSanitizerCoverage::InjectTraceForDiv( 845 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 846 for (auto *BO : DivTraceTargets) { 847 InstrumentationIRBuilder IRB(BO); 848 Value *A1 = BO->getOperand(1); 849 if (isa<ConstantInt>(A1)) continue; 850 if (!A1->getType()->isIntegerTy()) 851 continue; 852 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 853 int CallbackIdx = TypeSize == 32 ? 0 : 854 TypeSize == 64 ? 1 : -1; 855 if (CallbackIdx < 0) continue; 856 auto Ty = Type::getIntNTy(*C, TypeSize); 857 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 858 {IRB.CreateIntCast(A1, Ty, true)}); 859 } 860 } 861 862 void ModuleSanitizerCoverage::InjectTraceForGep( 863 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 864 for (auto *GEP : GepTraceTargets) { 865 InstrumentationIRBuilder IRB(GEP); 866 for (Use &Idx : GEP->indices()) 867 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 868 IRB.CreateCall(SanCovTraceGepFunction, 869 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 870 } 871 } 872 873 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 874 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 875 auto CallbackIdx = [&](Type *ElementTy) -> int { 876 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 877 return TypeSize == 8 ? 0 878 : TypeSize == 16 ? 1 879 : TypeSize == 32 ? 2 880 : TypeSize == 64 ? 3 881 : TypeSize == 128 ? 4 882 : -1; 883 }; 884 for (auto *LI : Loads) { 885 InstrumentationIRBuilder IRB(LI); 886 auto Ptr = LI->getPointerOperand(); 887 int Idx = CallbackIdx(LI->getType()); 888 if (Idx < 0) 889 continue; 890 IRB.CreateCall(SanCovLoadFunction[Idx], Ptr); 891 } 892 for (auto *SI : Stores) { 893 InstrumentationIRBuilder IRB(SI); 894 auto Ptr = SI->getPointerOperand(); 895 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 896 if (Idx < 0) 897 continue; 898 IRB.CreateCall(SanCovStoreFunction[Idx], Ptr); 899 } 900 } 901 902 void ModuleSanitizerCoverage::InjectTraceForCmp( 903 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 904 for (auto *I : CmpTraceTargets) { 905 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 906 InstrumentationIRBuilder IRB(ICMP); 907 Value *A0 = ICMP->getOperand(0); 908 Value *A1 = ICMP->getOperand(1); 909 if (!A0->getType()->isIntegerTy()) 910 continue; 911 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 912 int CallbackIdx = TypeSize == 8 ? 0 : 913 TypeSize == 16 ? 1 : 914 TypeSize == 32 ? 2 : 915 TypeSize == 64 ? 3 : -1; 916 if (CallbackIdx < 0) continue; 917 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 918 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 919 bool FirstIsConst = isa<ConstantInt>(A0); 920 bool SecondIsConst = isa<ConstantInt>(A1); 921 // If both are const, then we don't need such a comparison. 922 if (FirstIsConst && SecondIsConst) continue; 923 // If only one is const, then make it the first callback argument. 924 if (FirstIsConst || SecondIsConst) { 925 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 926 if (SecondIsConst) 927 std::swap(A0, A1); 928 } 929 930 auto Ty = Type::getIntNTy(*C, TypeSize); 931 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 932 IRB.CreateIntCast(A1, Ty, true)}); 933 } 934 } 935 } 936 937 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 938 size_t Idx, 939 bool IsLeafFunc) { 940 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 941 bool IsEntryBB = &BB == &F.getEntryBlock(); 942 DebugLoc EntryLoc; 943 if (IsEntryBB) { 944 if (auto SP = F.getSubprogram()) 945 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 946 // Keep static allocas and llvm.localescape calls in the entry block. Even 947 // if we aren't splitting the block, it's nice for allocas to be before 948 // calls. 949 IP = PrepareToSplitEntryBlock(BB, IP); 950 } 951 952 InstrumentationIRBuilder IRB(&*IP); 953 if (EntryLoc) 954 IRB.SetCurrentDebugLocation(EntryLoc); 955 if (Options.TracePC) { 956 IRB.CreateCall(SanCovTracePC) 957 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 958 } 959 if (Options.TracePCGuard) { 960 auto GuardPtr = IRB.CreateIntToPtr( 961 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 962 ConstantInt::get(IntptrTy, Idx * 4)), 963 PtrTy); 964 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 965 } 966 if (Options.Inline8bitCounters) { 967 auto CounterPtr = IRB.CreateGEP( 968 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 969 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 970 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 971 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 972 auto Store = IRB.CreateStore(Inc, CounterPtr); 973 Load->setNoSanitizeMetadata(); 974 Store->setNoSanitizeMetadata(); 975 } 976 if (Options.InlineBoolFlag) { 977 auto FlagPtr = IRB.CreateGEP( 978 FunctionBoolArray->getValueType(), FunctionBoolArray, 979 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 980 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 981 auto ThenTerm = SplitBlockAndInsertIfThen( 982 IRB.CreateIsNull(Load), &*IP, false, 983 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 984 IRBuilder<> ThenIRB(ThenTerm); 985 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 986 Load->setNoSanitizeMetadata(); 987 Store->setNoSanitizeMetadata(); 988 } 989 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 990 // Check stack depth. If it's the deepest so far, record it. 991 Module *M = F.getParent(); 992 Function *GetFrameAddr = Intrinsic::getDeclaration( 993 M, Intrinsic::frameaddress, 994 IRB.getPtrTy(M->getDataLayout().getAllocaAddrSpace())); 995 auto FrameAddrPtr = 996 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 997 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 998 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 999 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1000 auto ThenTerm = SplitBlockAndInsertIfThen( 1001 IsStackLower, &*IP, false, 1002 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 1003 IRBuilder<> ThenIRB(ThenTerm); 1004 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1005 LowestStack->setNoSanitizeMetadata(); 1006 Store->setNoSanitizeMetadata(); 1007 } 1008 } 1009 1010 std::string 1011 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1012 if (TargetTriple.isOSBinFormatCOFF()) { 1013 if (Section == SanCovCountersSectionName) 1014 return ".SCOV$CM"; 1015 if (Section == SanCovBoolFlagSectionName) 1016 return ".SCOV$BM"; 1017 if (Section == SanCovPCsSectionName) 1018 return ".SCOVP$M"; 1019 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1020 } 1021 if (TargetTriple.isOSBinFormatMachO()) 1022 return "__DATA,__" + Section; 1023 return "__" + Section; 1024 } 1025 1026 std::string 1027 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1028 if (TargetTriple.isOSBinFormatMachO()) 1029 return "\1section$start$__DATA$__" + Section; 1030 return "__start___" + Section; 1031 } 1032 1033 std::string 1034 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1035 if (TargetTriple.isOSBinFormatMachO()) 1036 return "\1section$end$__DATA$__" + Section; 1037 return "__stop___" + Section; 1038 } 1039 1040 void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) { 1041 SmallVector<Constant *, 32> CFs; 1042 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 1043 1044 for (auto &BB : F) { 1045 // blockaddress can not be used on function's entry block. 1046 if (&BB == &F.getEntryBlock()) 1047 CFs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 1048 else 1049 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(&BB), 1050 PtrTy)); 1051 1052 for (auto SuccBB : successors(&BB)) { 1053 assert(SuccBB != &F.getEntryBlock()); 1054 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(SuccBB), 1055 PtrTy)); 1056 } 1057 1058 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1059 1060 for (auto &Inst : BB) { 1061 if (CallBase *CB = dyn_cast<CallBase>(&Inst)) { 1062 if (CB->isIndirectCall()) { 1063 // TODO(navidem): handle indirect calls, for now mark its existence. 1064 CFs.push_back((Constant *)IRB.CreateIntToPtr( 1065 ConstantInt::get(IntptrTy, -1), PtrTy)); 1066 } else { 1067 auto CalledF = CB->getCalledFunction(); 1068 if (CalledF && !CalledF->isIntrinsic()) 1069 CFs.push_back( 1070 (Constant *)IRB.CreatePointerCast(CalledF, PtrTy)); 1071 } 1072 } 1073 } 1074 1075 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1076 } 1077 1078 FunctionCFsArray = CreateFunctionLocalArrayInSection( 1079 CFs.size(), F, PtrTy, SanCovCFsSectionName); 1080 FunctionCFsArray->setInitializer( 1081 ConstantArray::get(ArrayType::get(PtrTy, CFs.size()), CFs)); 1082 FunctionCFsArray->setConstant(true); 1083 } 1084