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/Constants.h" 20 #include "llvm/IR/DataLayout.h" 21 #include "llvm/IR/Dominators.h" 22 #include "llvm/IR/EHPersonalities.h" 23 #include "llvm/IR/Function.h" 24 #include "llvm/IR/GlobalVariable.h" 25 #include "llvm/IR/IRBuilder.h" 26 #include "llvm/IR/IntrinsicInst.h" 27 #include "llvm/IR/Intrinsics.h" 28 #include "llvm/IR/LLVMContext.h" 29 #include "llvm/IR/MDBuilder.h" 30 #include "llvm/IR/Module.h" 31 #include "llvm/IR/Type.h" 32 #include "llvm/IR/ValueSymbolTable.h" 33 #include "llvm/Support/CommandLine.h" 34 #include "llvm/Support/SpecialCaseList.h" 35 #include "llvm/Support/VirtualFileSystem.h" 36 #include "llvm/TargetParser/Triple.h" 37 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 38 #include "llvm/Transforms/Utils/ModuleUtils.h" 39 40 using namespace llvm; 41 42 #define DEBUG_TYPE "sancov" 43 44 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 45 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 46 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 47 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 48 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 49 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 50 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 51 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 52 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 53 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 54 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 55 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 56 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 57 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 58 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 59 const char SanCovStore1[] = "__sanitizer_cov_store1"; 60 const char SanCovStore2[] = "__sanitizer_cov_store2"; 61 const char SanCovStore4[] = "__sanitizer_cov_store4"; 62 const char SanCovStore8[] = "__sanitizer_cov_store8"; 63 const char SanCovStore16[] = "__sanitizer_cov_store16"; 64 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 65 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 66 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 67 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 68 const char SanCovModuleCtorTracePcGuardName[] = 69 "sancov.module_ctor_trace_pc_guard"; 70 const char SanCovModuleCtor8bitCountersName[] = 71 "sancov.module_ctor_8bit_counters"; 72 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 73 static const uint64_t SanCtorAndDtorPriority = 2; 74 75 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 76 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 77 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 78 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 79 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 80 const char SanCovCFsInitName[] = "__sanitizer_cov_cfs_init"; 81 82 const char SanCovGuardsSectionName[] = "sancov_guards"; 83 const char SanCovCountersSectionName[] = "sancov_cntrs"; 84 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 85 const char SanCovPCsSectionName[] = "sancov_pcs"; 86 const char SanCovCFsSectionName[] = "sancov_cfs"; 87 const char SanCovCallbackGateSectionName[] = "sancov_gate"; 88 89 const char SanCovLowestStackName[] = "__sancov_lowest_stack"; 90 const char SanCovCallbackGateName[] = "__sancov_should_track"; 91 92 static cl::opt<int> ClCoverageLevel( 93 "sanitizer-coverage-level", 94 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 95 "3: all blocks and critical edges"), 96 cl::Hidden); 97 98 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 99 cl::desc("Experimental pc tracing"), cl::Hidden); 100 101 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 102 cl::desc("pc tracing with a guard"), 103 cl::Hidden); 104 105 // If true, we create a global variable that contains PCs of all instrumented 106 // BBs, put this global into a named section, and pass this section's bounds 107 // to __sanitizer_cov_pcs_init. 108 // This way the coverage instrumentation does not need to acquire the PCs 109 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 110 // inline-bool-flag. 111 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 112 cl::desc("create a static PC table"), 113 cl::Hidden); 114 115 static cl::opt<bool> 116 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 117 cl::desc("increments 8-bit counter for every edge"), 118 cl::Hidden); 119 120 static cl::opt<bool> 121 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 122 cl::desc("sets a boolean flag for every edge"), 123 cl::Hidden); 124 125 static cl::opt<bool> 126 ClCMPTracing("sanitizer-coverage-trace-compares", 127 cl::desc("Tracing of CMP and similar instructions"), 128 cl::Hidden); 129 130 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 131 cl::desc("Tracing of DIV instructions"), 132 cl::Hidden); 133 134 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads", 135 cl::desc("Tracing of load instructions"), 136 cl::Hidden); 137 138 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 139 cl::desc("Tracing of store instructions"), 140 cl::Hidden); 141 142 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 143 cl::desc("Tracing of GEP instructions"), 144 cl::Hidden); 145 146 static cl::opt<bool> 147 ClPruneBlocks("sanitizer-coverage-prune-blocks", 148 cl::desc("Reduce the number of instrumented blocks"), 149 cl::Hidden, cl::init(true)); 150 151 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 152 cl::desc("max stack depth tracing"), 153 cl::Hidden); 154 155 static cl::opt<bool> 156 ClCollectCF("sanitizer-coverage-control-flow", 157 cl::desc("collect control flow for each function"), cl::Hidden); 158 159 static cl::opt<bool> ClGatedCallbacks( 160 "sanitizer-coverage-gated-trace-callbacks", 161 cl::desc("Gate the invocation of the tracing callbacks on a global variable" 162 ". Currently only supported for trace-pc-guard and trace-cmp."), 163 cl::Hidden, cl::init(false)); 164 165 namespace { 166 167 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 168 SanitizerCoverageOptions Res; 169 switch (LegacyCoverageLevel) { 170 case 0: 171 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 172 break; 173 case 1: 174 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 175 break; 176 case 2: 177 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 178 break; 179 case 3: 180 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 181 break; 182 case 4: 183 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 184 Res.IndirectCalls = true; 185 break; 186 } 187 return Res; 188 } 189 190 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 191 // Sets CoverageType and IndirectCalls. 192 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 193 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 194 Options.IndirectCalls |= CLOpts.IndirectCalls; 195 Options.TraceCmp |= ClCMPTracing; 196 Options.TraceDiv |= ClDIVTracing; 197 Options.TraceGep |= ClGEPTracing; 198 Options.TracePC |= ClTracePC; 199 Options.TracePCGuard |= ClTracePCGuard; 200 Options.Inline8bitCounters |= ClInline8bitCounters; 201 Options.InlineBoolFlag |= ClInlineBoolFlag; 202 Options.PCTable |= ClCreatePCTable; 203 Options.NoPrune |= !ClPruneBlocks; 204 Options.StackDepth |= ClStackDepth; 205 Options.TraceLoads |= ClLoadTracing; 206 Options.TraceStores |= ClStoreTracing; 207 Options.GatedCallbacks |= ClGatedCallbacks; 208 if (!Options.TracePCGuard && !Options.TracePC && 209 !Options.Inline8bitCounters && !Options.StackDepth && 210 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 211 Options.TracePCGuard = true; // TracePCGuard is default. 212 Options.CollectControlFlow |= ClCollectCF; 213 return Options; 214 } 215 216 class ModuleSanitizerCoverage { 217 public: 218 using DomTreeCallback = function_ref<const DominatorTree &(Function &F)>; 219 using PostDomTreeCallback = 220 function_ref<const PostDominatorTree &(Function &F)>; 221 222 ModuleSanitizerCoverage(Module &M, DomTreeCallback DTCallback, 223 PostDomTreeCallback PDTCallback, 224 const SanitizerCoverageOptions &Options, 225 const SpecialCaseList *Allowlist, 226 const SpecialCaseList *Blocklist) 227 : M(M), DTCallback(DTCallback), PDTCallback(PDTCallback), 228 Options(Options), Allowlist(Allowlist), Blocklist(Blocklist) {} 229 230 bool instrumentModule(); 231 232 private: 233 void createFunctionControlFlow(Function &F); 234 void instrumentFunction(Function &F); 235 void InjectCoverageForIndirectCalls(Function &F, 236 ArrayRef<Instruction *> IndirCalls); 237 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets, 238 Value *&FunctionGateCmp); 239 void InjectTraceForDiv(Function &F, 240 ArrayRef<BinaryOperator *> DivTraceTargets); 241 void InjectTraceForGep(Function &F, 242 ArrayRef<GetElementPtrInst *> GepTraceTargets); 243 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 244 ArrayRef<StoreInst *> Stores); 245 void InjectTraceForSwitch(Function &F, 246 ArrayRef<Instruction *> SwitchTraceTargets, 247 Value *&FunctionGateCmp); 248 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 249 Value *&FunctionGateCmp, bool IsLeafFunc); 250 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 251 Function &F, Type *Ty, 252 const char *Section); 253 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 254 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 255 Instruction *CreateGateBranch(Function &F, Value *&FunctionGateCmp, 256 Instruction *I); 257 Value *CreateFunctionLocalGateCmp(IRBuilder<> &IRB); 258 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 259 Value *&FunctionGateCmp, bool IsLeafFunc); 260 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 261 const char *InitFunctionName, Type *Ty, 262 const char *Section); 263 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 264 Type *Ty); 265 266 std::string getSectionName(const std::string &Section) const; 267 std::string getSectionStart(const std::string &Section) const; 268 std::string getSectionEnd(const std::string &Section) const; 269 270 Module &M; 271 DomTreeCallback DTCallback; 272 PostDomTreeCallback PDTCallback; 273 274 FunctionCallee SanCovTracePCIndir; 275 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 276 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 277 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 278 std::array<FunctionCallee, 5> SanCovLoadFunction; 279 std::array<FunctionCallee, 5> SanCovStoreFunction; 280 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 281 FunctionCallee SanCovTraceGepFunction; 282 FunctionCallee SanCovTraceSwitchFunction; 283 GlobalVariable *SanCovLowestStack; 284 GlobalVariable *SanCovCallbackGate; 285 Type *PtrTy, *IntptrTy, *Int64Ty, *Int32Ty, *Int16Ty, *Int8Ty, *Int1Ty; 286 Module *CurModule; 287 std::string CurModuleUniqueId; 288 Triple TargetTriple; 289 LLVMContext *C; 290 const DataLayout *DL; 291 292 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 293 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 294 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 295 GlobalVariable *FunctionPCsArray; // for pc-table. 296 GlobalVariable *FunctionCFsArray; // for control flow table 297 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 298 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 299 300 SanitizerCoverageOptions Options; 301 302 const SpecialCaseList *Allowlist; 303 const SpecialCaseList *Blocklist; 304 }; 305 } // namespace 306 307 PreservedAnalyses SanitizerCoveragePass::run(Module &M, 308 ModuleAnalysisManager &MAM) { 309 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 310 auto DTCallback = [&FAM](Function &F) -> const DominatorTree & { 311 return FAM.getResult<DominatorTreeAnalysis>(F); 312 }; 313 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree & { 314 return FAM.getResult<PostDominatorTreeAnalysis>(F); 315 }; 316 ModuleSanitizerCoverage ModuleSancov(M, DTCallback, PDTCallback, 317 OverrideFromCL(Options), Allowlist.get(), 318 Blocklist.get()); 319 if (!ModuleSancov.instrumentModule()) 320 return PreservedAnalyses::all(); 321 322 PreservedAnalyses PA = PreservedAnalyses::none(); 323 // GlobalsAA is considered stateless and does not get invalidated unless 324 // explicitly invalidated; PreservedAnalyses::none() is not enough. Sanitizers 325 // make changes that require GlobalsAA to be invalidated. 326 PA.abandon<GlobalsAA>(); 327 return PA; 328 } 329 330 std::pair<Value *, Value *> 331 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 332 Type *Ty) { 333 // Use ExternalWeak so that if all sections are discarded due to section 334 // garbage collection, the linker will not report undefined symbol errors. 335 // Windows defines the start/stop symbols in compiler-rt so no need for 336 // ExternalWeak. 337 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 338 ? GlobalVariable::ExternalLinkage 339 : GlobalVariable::ExternalWeakLinkage; 340 GlobalVariable *SecStart = 341 new GlobalVariable(M, Ty, false, Linkage, nullptr, 342 getSectionStart(Section)); 343 SecStart->setVisibility(GlobalValue::HiddenVisibility); 344 GlobalVariable *SecEnd = 345 new GlobalVariable(M, Ty, false, Linkage, nullptr, 346 getSectionEnd(Section)); 347 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 348 IRBuilder<> IRB(M.getContext()); 349 if (!TargetTriple.isOSBinFormatCOFF()) 350 return std::make_pair(SecStart, SecEnd); 351 352 // Account for the fact that on windows-msvc __start_* symbols actually 353 // point to a uint64_t before the start of the array. 354 auto GEP = 355 IRB.CreatePtrAdd(SecStart, ConstantInt::get(IntptrTy, sizeof(uint64_t))); 356 return std::make_pair(GEP, SecEnd); 357 } 358 359 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 360 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 361 const char *Section) { 362 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 363 auto SecStart = SecStartEnd.first; 364 auto SecEnd = SecStartEnd.second; 365 Function *CtorFunc; 366 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 367 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 368 assert(CtorFunc->getName() == CtorName); 369 370 if (TargetTriple.supportsCOMDAT()) { 371 // Use comdat to dedup CtorFunc. 372 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 373 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 374 } else { 375 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 376 } 377 378 if (TargetTriple.isOSBinFormatCOFF()) { 379 // In COFF files, if the contructors are set as COMDAT (they are because 380 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 381 // functions and data) is used, the constructors get stripped. To prevent 382 // this, give the constructors weak ODR linkage and ensure the linker knows 383 // to include the sancov constructor. This way the linker can deduplicate 384 // the constructors but always leave one copy. 385 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 386 } 387 return CtorFunc; 388 } 389 390 bool ModuleSanitizerCoverage::instrumentModule() { 391 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 392 return false; 393 if (Allowlist && 394 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 395 return false; 396 if (Blocklist && 397 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 398 return false; 399 C = &(M.getContext()); 400 DL = &M.getDataLayout(); 401 CurModule = &M; 402 CurModuleUniqueId = getUniqueModuleId(CurModule); 403 TargetTriple = Triple(M.getTargetTriple()); 404 FunctionGuardArray = nullptr; 405 Function8bitCounterArray = nullptr; 406 FunctionBoolArray = nullptr; 407 FunctionPCsArray = nullptr; 408 FunctionCFsArray = nullptr; 409 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 410 PtrTy = PointerType::getUnqual(*C); 411 Type *VoidTy = Type::getVoidTy(*C); 412 IRBuilder<> IRB(*C); 413 Int64Ty = IRB.getInt64Ty(); 414 Int32Ty = IRB.getInt32Ty(); 415 Int16Ty = IRB.getInt16Ty(); 416 Int8Ty = IRB.getInt8Ty(); 417 Int1Ty = IRB.getInt1Ty(); 418 419 SanCovTracePCIndir = 420 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 421 // Make sure smaller parameters are zero-extended to i64 if required by the 422 // target ABI. 423 AttributeList SanCovTraceCmpZeroExtAL; 424 SanCovTraceCmpZeroExtAL = 425 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 426 SanCovTraceCmpZeroExtAL = 427 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 428 429 SanCovTraceCmpFunction[0] = 430 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 431 IRB.getInt8Ty(), IRB.getInt8Ty()); 432 SanCovTraceCmpFunction[1] = 433 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 434 IRB.getInt16Ty(), IRB.getInt16Ty()); 435 SanCovTraceCmpFunction[2] = 436 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 437 IRB.getInt32Ty(), IRB.getInt32Ty()); 438 SanCovTraceCmpFunction[3] = 439 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 440 441 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 442 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 443 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 444 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 445 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 446 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 447 SanCovTraceConstCmpFunction[3] = 448 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 449 450 // Loads. 451 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, PtrTy); 452 SanCovLoadFunction[1] = 453 M.getOrInsertFunction(SanCovLoad2, VoidTy, PtrTy); 454 SanCovLoadFunction[2] = 455 M.getOrInsertFunction(SanCovLoad4, VoidTy, PtrTy); 456 SanCovLoadFunction[3] = 457 M.getOrInsertFunction(SanCovLoad8, VoidTy, PtrTy); 458 SanCovLoadFunction[4] = 459 M.getOrInsertFunction(SanCovLoad16, VoidTy, PtrTy); 460 // Stores. 461 SanCovStoreFunction[0] = 462 M.getOrInsertFunction(SanCovStore1, VoidTy, PtrTy); 463 SanCovStoreFunction[1] = 464 M.getOrInsertFunction(SanCovStore2, VoidTy, PtrTy); 465 SanCovStoreFunction[2] = 466 M.getOrInsertFunction(SanCovStore4, VoidTy, PtrTy); 467 SanCovStoreFunction[3] = 468 M.getOrInsertFunction(SanCovStore8, VoidTy, PtrTy); 469 SanCovStoreFunction[4] = 470 M.getOrInsertFunction(SanCovStore16, VoidTy, PtrTy); 471 472 { 473 AttributeList AL; 474 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 475 SanCovTraceDivFunction[0] = 476 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 477 } 478 SanCovTraceDivFunction[1] = 479 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 480 SanCovTraceGepFunction = 481 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 482 SanCovTraceSwitchFunction = 483 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, PtrTy); 484 485 Constant *SanCovLowestStackConstant = 486 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 487 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 488 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 489 C->emitError(StringRef("'") + SanCovLowestStackName + 490 "' should not be declared by the user"); 491 return true; 492 } 493 SanCovLowestStack->setThreadLocalMode( 494 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 495 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 496 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 497 498 if (Options.GatedCallbacks) { 499 if (!Options.TracePCGuard && !Options.TraceCmp) { 500 C->emitError(StringRef("'") + ClGatedCallbacks.ArgStr + 501 "' is only supported with trace-pc-guard or trace-cmp"); 502 return true; 503 } 504 505 SanCovCallbackGate = cast<GlobalVariable>( 506 M.getOrInsertGlobal(SanCovCallbackGateName, Int64Ty)); 507 SanCovCallbackGate->setSection( 508 getSectionName(SanCovCallbackGateSectionName)); 509 SanCovCallbackGate->setInitializer(Constant::getNullValue(Int64Ty)); 510 SanCovCallbackGate->setLinkage(GlobalVariable::LinkOnceAnyLinkage); 511 SanCovCallbackGate->setVisibility(GlobalVariable::HiddenVisibility); 512 appendToCompilerUsed(M, SanCovCallbackGate); 513 } 514 515 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 516 SanCovTracePCGuard = 517 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, PtrTy); 518 519 for (auto &F : M) 520 instrumentFunction(F); 521 522 Function *Ctor = nullptr; 523 524 if (FunctionGuardArray) 525 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 526 SanCovTracePCGuardInitName, Int32Ty, 527 SanCovGuardsSectionName); 528 if (Function8bitCounterArray) 529 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 530 SanCov8bitCountersInitName, Int8Ty, 531 SanCovCountersSectionName); 532 if (FunctionBoolArray) { 533 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 534 SanCovBoolFlagInitName, Int1Ty, 535 SanCovBoolFlagSectionName); 536 } 537 if (Ctor && Options.PCTable) { 538 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 539 FunctionCallee InitFunction = declareSanitizerInitFunction( 540 M, SanCovPCsInitName, {PtrTy, PtrTy}); 541 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 542 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 543 } 544 545 if (Ctor && Options.CollectControlFlow) { 546 auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrTy); 547 FunctionCallee InitFunction = declareSanitizerInitFunction( 548 M, SanCovCFsInitName, {PtrTy, PtrTy}); 549 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 550 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 551 } 552 553 appendToUsed(M, GlobalsToAppendToUsed); 554 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 555 return true; 556 } 557 558 // True if block has successors and it dominates all of them. 559 static bool isFullDominator(const BasicBlock *BB, const DominatorTree &DT) { 560 if (succ_empty(BB)) 561 return false; 562 563 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 564 return DT.dominates(BB, SUCC); 565 }); 566 } 567 568 // True if block has predecessors and it postdominates all of them. 569 static bool isFullPostDominator(const BasicBlock *BB, 570 const PostDominatorTree &PDT) { 571 if (pred_empty(BB)) 572 return false; 573 574 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 575 return PDT.dominates(BB, PRED); 576 }); 577 } 578 579 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 580 const DominatorTree &DT, 581 const PostDominatorTree &PDT, 582 const SanitizerCoverageOptions &Options) { 583 // Don't insert coverage for blocks containing nothing but unreachable: we 584 // will never call __sanitizer_cov() for them, so counting them in 585 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 586 // percentage. Also, unreachable instructions frequently have no debug 587 // locations. 588 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 589 return false; 590 591 // Don't insert coverage into blocks without a valid insertion point 592 // (catchswitch blocks). 593 if (BB->getFirstInsertionPt() == BB->end()) 594 return false; 595 596 if (Options.NoPrune || &F.getEntryBlock() == BB) 597 return true; 598 599 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 600 &F.getEntryBlock() != BB) 601 return false; 602 603 // Do not instrument full dominators, or full post-dominators with multiple 604 // predecessors. 605 return !isFullDominator(BB, DT) 606 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 607 } 608 609 // Returns true iff From->To is a backedge. 610 // A twist here is that we treat From->To as a backedge if 611 // * To dominates From or 612 // * To->UniqueSuccessor dominates From 613 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 614 const DominatorTree &DT) { 615 if (DT.dominates(To, From)) 616 return true; 617 if (auto Next = To->getUniqueSuccessor()) 618 if (DT.dominates(Next, From)) 619 return true; 620 return false; 621 } 622 623 // Prunes uninteresting Cmp instrumentation: 624 // * CMP instructions that feed into loop backedge branch. 625 // 626 // Note that Cmp pruning is controlled by the same flag as the 627 // BB pruning. 628 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree &DT, 629 const SanitizerCoverageOptions &Options) { 630 if (!Options.NoPrune) 631 if (CMP->hasOneUse()) 632 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 633 for (BasicBlock *B : BR->successors()) 634 if (IsBackEdge(BR->getParent(), B, DT)) 635 return false; 636 return true; 637 } 638 639 void ModuleSanitizerCoverage::instrumentFunction(Function &F) { 640 if (F.empty()) 641 return; 642 if (F.getName().contains(".module_ctor")) 643 return; // Should not instrument sanitizer init functions. 644 if (F.getName().starts_with("__sanitizer_")) 645 return; // Don't instrument __sanitizer_* callbacks. 646 // Don't touch available_externally functions, their actual body is elewhere. 647 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 648 return; 649 // Don't instrument MSVC CRT configuration helpers. They may run before normal 650 // initialization. 651 if (F.getName() == "__local_stdio_printf_options" || 652 F.getName() == "__local_stdio_scanf_options") 653 return; 654 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 655 return; 656 // Don't instrument functions using SEH for now. Splitting basic blocks like 657 // we do for coverage breaks WinEHPrepare. 658 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 659 if (F.hasPersonalityFn() && 660 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 661 return; 662 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 663 return; 664 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 665 return; 666 // Do not apply any instrumentation for naked functions. 667 if (F.hasFnAttribute(Attribute::Naked)) 668 return; 669 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 670 return; 671 if (F.hasFnAttribute(Attribute::DisableSanitizerInstrumentation)) 672 return; 673 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) { 674 SplitAllCriticalEdges( 675 F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 676 } 677 SmallVector<Instruction *, 8> IndirCalls; 678 SmallVector<BasicBlock *, 16> BlocksToInstrument; 679 SmallVector<Instruction *, 8> CmpTraceTargets; 680 SmallVector<Instruction *, 8> SwitchTraceTargets; 681 SmallVector<BinaryOperator *, 8> DivTraceTargets; 682 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 683 SmallVector<LoadInst *, 8> Loads; 684 SmallVector<StoreInst *, 8> Stores; 685 686 const DominatorTree &DT = DTCallback(F); 687 const PostDominatorTree &PDT = PDTCallback(F); 688 bool IsLeafFunc = true; 689 690 for (auto &BB : F) { 691 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 692 BlocksToInstrument.push_back(&BB); 693 for (auto &Inst : BB) { 694 if (Options.IndirectCalls) { 695 CallBase *CB = dyn_cast<CallBase>(&Inst); 696 if (CB && CB->isIndirectCall()) 697 IndirCalls.push_back(&Inst); 698 } 699 if (Options.TraceCmp) { 700 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 701 if (IsInterestingCmp(CMP, DT, Options)) 702 CmpTraceTargets.push_back(&Inst); 703 if (isa<SwitchInst>(&Inst)) 704 SwitchTraceTargets.push_back(&Inst); 705 } 706 if (Options.TraceDiv) 707 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 708 if (BO->getOpcode() == Instruction::SDiv || 709 BO->getOpcode() == Instruction::UDiv) 710 DivTraceTargets.push_back(BO); 711 if (Options.TraceGep) 712 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 713 GepTraceTargets.push_back(GEP); 714 if (Options.TraceLoads) 715 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 716 Loads.push_back(LI); 717 if (Options.TraceStores) 718 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 719 Stores.push_back(SI); 720 if (Options.StackDepth) 721 if (isa<InvokeInst>(Inst) || 722 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 723 IsLeafFunc = false; 724 } 725 } 726 727 if (Options.CollectControlFlow) 728 createFunctionControlFlow(F); 729 730 Value *FunctionGateCmp = nullptr; 731 InjectCoverage(F, BlocksToInstrument, FunctionGateCmp, IsLeafFunc); 732 InjectCoverageForIndirectCalls(F, IndirCalls); 733 InjectTraceForCmp(F, CmpTraceTargets, FunctionGateCmp); 734 InjectTraceForSwitch(F, SwitchTraceTargets, FunctionGateCmp); 735 InjectTraceForDiv(F, DivTraceTargets); 736 InjectTraceForGep(F, GepTraceTargets); 737 InjectTraceForLoadsAndStores(F, Loads, Stores); 738 } 739 740 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 741 size_t NumElements, Function &F, Type *Ty, const char *Section) { 742 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 743 auto Array = new GlobalVariable( 744 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 745 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 746 747 if (TargetTriple.supportsCOMDAT() && 748 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 749 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 750 Array->setComdat(Comdat); 751 Array->setSection(getSectionName(Section)); 752 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue())); 753 754 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 755 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 756 // section(s) as a unit, so we conservatively retain all unconditionally in 757 // the compiler. 758 // 759 // With comdat (COFF/ELF), the linker can guarantee the associated sections 760 // will be retained or discarded as a unit, so llvm.compiler.used is 761 // sufficient. Otherwise, conservatively make all of them retained by the 762 // linker. 763 if (Array->hasComdat()) 764 GlobalsToAppendToCompilerUsed.push_back(Array); 765 else 766 GlobalsToAppendToUsed.push_back(Array); 767 768 return Array; 769 } 770 771 GlobalVariable * 772 ModuleSanitizerCoverage::CreatePCArray(Function &F, 773 ArrayRef<BasicBlock *> AllBlocks) { 774 size_t N = AllBlocks.size(); 775 assert(N); 776 SmallVector<Constant *, 32> PCs; 777 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 778 for (size_t i = 0; i < N; i++) { 779 if (&F.getEntryBlock() == AllBlocks[i]) { 780 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 781 PCs.push_back((Constant *)IRB.CreateIntToPtr( 782 ConstantInt::get(IntptrTy, 1), PtrTy)); 783 } else { 784 PCs.push_back((Constant *)IRB.CreatePointerCast( 785 BlockAddress::get(AllBlocks[i]), PtrTy)); 786 PCs.push_back(Constant::getNullValue(PtrTy)); 787 } 788 } 789 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, PtrTy, 790 SanCovPCsSectionName); 791 PCArray->setInitializer( 792 ConstantArray::get(ArrayType::get(PtrTy, N * 2), PCs)); 793 PCArray->setConstant(true); 794 795 return PCArray; 796 } 797 798 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 799 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 800 if (Options.TracePCGuard) 801 FunctionGuardArray = CreateFunctionLocalArrayInSection( 802 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 803 804 if (Options.Inline8bitCounters) 805 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 806 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 807 if (Options.InlineBoolFlag) 808 FunctionBoolArray = CreateFunctionLocalArrayInSection( 809 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 810 811 if (Options.PCTable) 812 FunctionPCsArray = CreatePCArray(F, AllBlocks); 813 } 814 815 Value *ModuleSanitizerCoverage::CreateFunctionLocalGateCmp(IRBuilder<> &IRB) { 816 auto Load = IRB.CreateLoad(Int64Ty, SanCovCallbackGate); 817 Load->setNoSanitizeMetadata(); 818 auto Cmp = IRB.CreateIsNotNull(Load); 819 Cmp->setName("sancov gate cmp"); 820 return Cmp; 821 } 822 823 Instruction *ModuleSanitizerCoverage::CreateGateBranch(Function &F, 824 Value *&FunctionGateCmp, 825 Instruction *IP) { 826 if (!FunctionGateCmp) { 827 // Create this in the entry block 828 BasicBlock &BB = F.getEntryBlock(); 829 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 830 IP = PrepareToSplitEntryBlock(BB, IP); 831 IRBuilder<> EntryIRB(&*IP); 832 FunctionGateCmp = CreateFunctionLocalGateCmp(EntryIRB); 833 } 834 // Set the branch weights in order to minimize the price paid when the 835 // gate is turned off, allowing the default enablement of this 836 // instrumentation with as little of a performance cost as possible 837 auto Weights = MDBuilder(*C).createBranchWeights(1, 100000); 838 return SplitBlockAndInsertIfThen(FunctionGateCmp, IP, false, Weights); 839 } 840 841 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 842 ArrayRef<BasicBlock *> AllBlocks, 843 Value *&FunctionGateCmp, 844 bool IsLeafFunc) { 845 if (AllBlocks.empty()) return false; 846 CreateFunctionLocalArrays(F, AllBlocks); 847 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 848 InjectCoverageAtBlock(F, *AllBlocks[i], i, FunctionGateCmp, IsLeafFunc); 849 return true; 850 } 851 852 // On every indirect call we call a run-time function 853 // __sanitizer_cov_indir_call* with two parameters: 854 // - callee address, 855 // - global cache array that contains CacheSize pointers (zero-initialized). 856 // The cache is used to speed up recording the caller-callee pairs. 857 // The address of the caller is passed implicitly via caller PC. 858 // CacheSize is encoded in the name of the run-time function. 859 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 860 Function &F, ArrayRef<Instruction *> IndirCalls) { 861 if (IndirCalls.empty()) 862 return; 863 assert(Options.TracePC || Options.TracePCGuard || 864 Options.Inline8bitCounters || Options.InlineBoolFlag); 865 for (auto *I : IndirCalls) { 866 InstrumentationIRBuilder IRB(I); 867 CallBase &CB = cast<CallBase>(*I); 868 Value *Callee = CB.getCalledOperand(); 869 if (isa<InlineAsm>(Callee)) 870 continue; 871 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 872 } 873 } 874 875 // For every switch statement we insert a call: 876 // __sanitizer_cov_trace_switch(CondValue, 877 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 878 879 void ModuleSanitizerCoverage::InjectTraceForSwitch( 880 Function &F, ArrayRef<Instruction *> SwitchTraceTargets, 881 Value *&FunctionGateCmp) { 882 for (auto *I : SwitchTraceTargets) { 883 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 884 InstrumentationIRBuilder IRB(I); 885 SmallVector<Constant *, 16> Initializers; 886 Value *Cond = SI->getCondition(); 887 if (Cond->getType()->getScalarSizeInBits() > 888 Int64Ty->getScalarSizeInBits()) 889 continue; 890 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 891 Initializers.push_back( 892 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 893 if (Cond->getType()->getScalarSizeInBits() < 894 Int64Ty->getScalarSizeInBits()) 895 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 896 for (auto It : SI->cases()) { 897 ConstantInt *C = It.getCaseValue(); 898 if (C->getType()->getScalarSizeInBits() < 64) 899 C = ConstantInt::get(C->getContext(), C->getValue().zext(64)); 900 Initializers.push_back(C); 901 } 902 llvm::sort(drop_begin(Initializers, 2), 903 [](const Constant *A, const Constant *B) { 904 return cast<ConstantInt>(A)->getLimitedValue() < 905 cast<ConstantInt>(B)->getLimitedValue(); 906 }); 907 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 908 GlobalVariable *GV = new GlobalVariable( 909 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 910 ConstantArray::get(ArrayOfInt64Ty, Initializers), 911 "__sancov_gen_cov_switch_values"); 912 if (Options.GatedCallbacks) { 913 auto GateBranch = CreateGateBranch(F, FunctionGateCmp, I); 914 IRBuilder<> GateIRB(GateBranch); 915 GateIRB.CreateCall(SanCovTraceSwitchFunction, {Cond, GV}); 916 } else { 917 IRB.CreateCall(SanCovTraceSwitchFunction, {Cond, GV}); 918 } 919 } 920 } 921 } 922 923 void ModuleSanitizerCoverage::InjectTraceForDiv( 924 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 925 for (auto *BO : DivTraceTargets) { 926 InstrumentationIRBuilder IRB(BO); 927 Value *A1 = BO->getOperand(1); 928 if (isa<ConstantInt>(A1)) continue; 929 if (!A1->getType()->isIntegerTy()) 930 continue; 931 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 932 int CallbackIdx = TypeSize == 32 ? 0 : 933 TypeSize == 64 ? 1 : -1; 934 if (CallbackIdx < 0) continue; 935 auto Ty = Type::getIntNTy(*C, TypeSize); 936 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 937 {IRB.CreateIntCast(A1, Ty, true)}); 938 } 939 } 940 941 void ModuleSanitizerCoverage::InjectTraceForGep( 942 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 943 for (auto *GEP : GepTraceTargets) { 944 InstrumentationIRBuilder IRB(GEP); 945 for (Use &Idx : GEP->indices()) 946 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 947 IRB.CreateCall(SanCovTraceGepFunction, 948 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 949 } 950 } 951 952 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 953 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 954 auto CallbackIdx = [&](Type *ElementTy) -> int { 955 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 956 return TypeSize == 8 ? 0 957 : TypeSize == 16 ? 1 958 : TypeSize == 32 ? 2 959 : TypeSize == 64 ? 3 960 : TypeSize == 128 ? 4 961 : -1; 962 }; 963 for (auto *LI : Loads) { 964 InstrumentationIRBuilder IRB(LI); 965 auto Ptr = LI->getPointerOperand(); 966 int Idx = CallbackIdx(LI->getType()); 967 if (Idx < 0) 968 continue; 969 IRB.CreateCall(SanCovLoadFunction[Idx], Ptr); 970 } 971 for (auto *SI : Stores) { 972 InstrumentationIRBuilder IRB(SI); 973 auto Ptr = SI->getPointerOperand(); 974 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 975 if (Idx < 0) 976 continue; 977 IRB.CreateCall(SanCovStoreFunction[Idx], Ptr); 978 } 979 } 980 981 void ModuleSanitizerCoverage::InjectTraceForCmp( 982 Function &F, ArrayRef<Instruction *> CmpTraceTargets, 983 Value *&FunctionGateCmp) { 984 for (auto *I : CmpTraceTargets) { 985 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 986 InstrumentationIRBuilder IRB(ICMP); 987 Value *A0 = ICMP->getOperand(0); 988 Value *A1 = ICMP->getOperand(1); 989 if (!A0->getType()->isIntegerTy()) 990 continue; 991 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 992 int CallbackIdx = TypeSize == 8 ? 0 : 993 TypeSize == 16 ? 1 : 994 TypeSize == 32 ? 2 : 995 TypeSize == 64 ? 3 : -1; 996 if (CallbackIdx < 0) continue; 997 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 998 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 999 bool FirstIsConst = isa<ConstantInt>(A0); 1000 bool SecondIsConst = isa<ConstantInt>(A1); 1001 // If both are const, then we don't need such a comparison. 1002 if (FirstIsConst && SecondIsConst) continue; 1003 // If only one is const, then make it the first callback argument. 1004 if (FirstIsConst || SecondIsConst) { 1005 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 1006 if (SecondIsConst) 1007 std::swap(A0, A1); 1008 } 1009 1010 auto Ty = Type::getIntNTy(*C, TypeSize); 1011 if (Options.GatedCallbacks) { 1012 auto GateBranch = CreateGateBranch(F, FunctionGateCmp, I); 1013 IRBuilder<> GateIRB(GateBranch); 1014 GateIRB.CreateCall(CallbackFunc, {GateIRB.CreateIntCast(A0, Ty, true), 1015 GateIRB.CreateIntCast(A1, Ty, true)}); 1016 } else { 1017 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 1018 IRB.CreateIntCast(A1, Ty, true)}); 1019 } 1020 } 1021 } 1022 } 1023 1024 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 1025 size_t Idx, 1026 Value *&FunctionGateCmp, 1027 bool IsLeafFunc) { 1028 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 1029 bool IsEntryBB = &BB == &F.getEntryBlock(); 1030 DebugLoc EntryLoc; 1031 if (IsEntryBB) { 1032 if (auto SP = F.getSubprogram()) 1033 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 1034 // Keep static allocas and llvm.localescape calls in the entry block. Even 1035 // if we aren't splitting the block, it's nice for allocas to be before 1036 // calls. 1037 IP = PrepareToSplitEntryBlock(BB, IP); 1038 } 1039 1040 InstrumentationIRBuilder IRB(&*IP); 1041 if (EntryLoc) 1042 IRB.SetCurrentDebugLocation(EntryLoc); 1043 if (Options.TracePC) { 1044 IRB.CreateCall(SanCovTracePC) 1045 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 1046 } 1047 if (Options.TracePCGuard) { 1048 auto GuardPtr = IRB.CreateConstInBoundsGEP2_64( 1049 FunctionGuardArray->getValueType(), FunctionGuardArray, 0, Idx); 1050 if (Options.GatedCallbacks) { 1051 Instruction *I = &*IP; 1052 auto GateBranch = CreateGateBranch(F, FunctionGateCmp, I); 1053 IRBuilder<> GateIRB(GateBranch); 1054 GateIRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 1055 } else { 1056 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 1057 } 1058 } 1059 if (Options.Inline8bitCounters) { 1060 auto CounterPtr = IRB.CreateGEP( 1061 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 1062 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1063 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 1064 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 1065 auto Store = IRB.CreateStore(Inc, CounterPtr); 1066 Load->setNoSanitizeMetadata(); 1067 Store->setNoSanitizeMetadata(); 1068 } 1069 if (Options.InlineBoolFlag) { 1070 auto FlagPtr = IRB.CreateGEP( 1071 FunctionBoolArray->getValueType(), FunctionBoolArray, 1072 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1073 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 1074 auto ThenTerm = SplitBlockAndInsertIfThen( 1075 IRB.CreateIsNull(Load), &*IP, false, 1076 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 1077 IRBuilder<> ThenIRB(ThenTerm); 1078 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 1079 Load->setNoSanitizeMetadata(); 1080 Store->setNoSanitizeMetadata(); 1081 } 1082 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 1083 // Check stack depth. If it's the deepest so far, record it. 1084 Module *M = F.getParent(); 1085 auto FrameAddrPtr = IRB.CreateIntrinsic( 1086 Intrinsic::frameaddress, 1087 IRB.getPtrTy(M->getDataLayout().getAllocaAddrSpace()), 1088 {Constant::getNullValue(Int32Ty)}); 1089 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1090 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1091 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1092 auto ThenTerm = SplitBlockAndInsertIfThen( 1093 IsStackLower, &*IP, false, 1094 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights()); 1095 IRBuilder<> ThenIRB(ThenTerm); 1096 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1097 LowestStack->setNoSanitizeMetadata(); 1098 Store->setNoSanitizeMetadata(); 1099 } 1100 } 1101 1102 std::string 1103 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1104 if (TargetTriple.isOSBinFormatCOFF()) { 1105 if (Section == SanCovCountersSectionName) 1106 return ".SCOV$CM"; 1107 if (Section == SanCovBoolFlagSectionName) 1108 return ".SCOV$BM"; 1109 if (Section == SanCovPCsSectionName) 1110 return ".SCOVP$M"; 1111 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1112 } 1113 if (TargetTriple.isOSBinFormatMachO()) 1114 return "__DATA,__" + Section; 1115 return "__" + Section; 1116 } 1117 1118 std::string 1119 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1120 if (TargetTriple.isOSBinFormatMachO()) 1121 return "\1section$start$__DATA$__" + Section; 1122 return "__start___" + Section; 1123 } 1124 1125 std::string 1126 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1127 if (TargetTriple.isOSBinFormatMachO()) 1128 return "\1section$end$__DATA$__" + Section; 1129 return "__stop___" + Section; 1130 } 1131 1132 void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) { 1133 SmallVector<Constant *, 32> CFs; 1134 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 1135 1136 for (auto &BB : F) { 1137 // blockaddress can not be used on function's entry block. 1138 if (&BB == &F.getEntryBlock()) 1139 CFs.push_back((Constant *)IRB.CreatePointerCast(&F, PtrTy)); 1140 else 1141 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(&BB), 1142 PtrTy)); 1143 1144 for (auto SuccBB : successors(&BB)) { 1145 assert(SuccBB != &F.getEntryBlock()); 1146 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(SuccBB), 1147 PtrTy)); 1148 } 1149 1150 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1151 1152 for (auto &Inst : BB) { 1153 if (CallBase *CB = dyn_cast<CallBase>(&Inst)) { 1154 if (CB->isIndirectCall()) { 1155 // TODO(navidem): handle indirect calls, for now mark its existence. 1156 CFs.push_back((Constant *)IRB.CreateIntToPtr( 1157 ConstantInt::get(IntptrTy, -1), PtrTy)); 1158 } else { 1159 auto CalledF = CB->getCalledFunction(); 1160 if (CalledF && !CalledF->isIntrinsic()) 1161 CFs.push_back( 1162 (Constant *)IRB.CreatePointerCast(CalledF, PtrTy)); 1163 } 1164 } 1165 } 1166 1167 CFs.push_back((Constant *)Constant::getNullValue(PtrTy)); 1168 } 1169 1170 FunctionCFsArray = CreateFunctionLocalArrayInSection( 1171 CFs.size(), F, PtrTy, SanCovCFsSectionName); 1172 FunctionCFsArray->setInitializer( 1173 ConstantArray::get(ArrayType::get(PtrTy, CFs.size()), CFs)); 1174 FunctionCFsArray->setConstant(true); 1175 } 1176