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