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/ADT/Triple.h" 17 #include "llvm/Analysis/EHPersonalities.h" 18 #include "llvm/Analysis/GlobalsModRef.h" 19 #include "llvm/Analysis/PostDominators.h" 20 #include "llvm/IR/Constant.h" 21 #include "llvm/IR/DataLayout.h" 22 #include "llvm/IR/Dominators.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/Module.h" 30 #include "llvm/IR/Type.h" 31 #include "llvm/InitializePasses.h" 32 #include "llvm/Support/CommandLine.h" 33 #include "llvm/Support/SpecialCaseList.h" 34 #include "llvm/Support/VirtualFileSystem.h" 35 #include "llvm/Transforms/Instrumentation.h" 36 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 37 #include "llvm/Transforms/Utils/ModuleUtils.h" 38 39 using namespace llvm; 40 41 #define DEBUG_TYPE "sancov" 42 43 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 44 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 45 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 46 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 47 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 48 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 49 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 50 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 51 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 52 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 53 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 54 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 55 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 56 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 57 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 58 const char SanCovStore1[] = "__sanitizer_cov_store1"; 59 const char SanCovStore2[] = "__sanitizer_cov_store2"; 60 const char SanCovStore4[] = "__sanitizer_cov_store4"; 61 const char SanCovStore8[] = "__sanitizer_cov_store8"; 62 const char SanCovStore16[] = "__sanitizer_cov_store16"; 63 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 64 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 65 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 66 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 67 const char SanCovModuleCtorTracePcGuardName[] = 68 "sancov.module_ctor_trace_pc_guard"; 69 const char SanCovModuleCtor8bitCountersName[] = 70 "sancov.module_ctor_8bit_counters"; 71 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 72 static const uint64_t SanCtorAndDtorPriority = 2; 73 74 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 75 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 76 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 77 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 78 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 79 const char SanCovCFsInitName[] = "__sanitizer_cov_cfs_init"; 80 81 const char SanCovGuardsSectionName[] = "sancov_guards"; 82 const char SanCovCountersSectionName[] = "sancov_cntrs"; 83 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 84 const char SanCovPCsSectionName[] = "sancov_pcs"; 85 const char SanCovCFsSectionName[] = "sancov_cfs"; 86 87 const char SanCovLowestStackName[] = "__sancov_lowest_stack"; 88 89 static cl::opt<int> ClCoverageLevel( 90 "sanitizer-coverage-level", 91 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 92 "3: all blocks and critical edges"), 93 cl::Hidden, cl::init(0)); 94 95 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 96 cl::desc("Experimental pc tracing"), cl::Hidden, 97 cl::init(false)); 98 99 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 100 cl::desc("pc tracing with a guard"), 101 cl::Hidden, cl::init(false)); 102 103 // If true, we create a global variable that contains PCs of all instrumented 104 // BBs, put this global into a named section, and pass this section's bounds 105 // to __sanitizer_cov_pcs_init. 106 // This way the coverage instrumentation does not need to acquire the PCs 107 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 108 // inline-bool-flag. 109 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 110 cl::desc("create a static PC table"), 111 cl::Hidden, cl::init(false)); 112 113 static cl::opt<bool> 114 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 115 cl::desc("increments 8-bit counter for every edge"), 116 cl::Hidden, cl::init(false)); 117 118 static cl::opt<bool> 119 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 120 cl::desc("sets a boolean flag for every edge"), cl::Hidden, 121 cl::init(false)); 122 123 static cl::opt<bool> 124 ClCMPTracing("sanitizer-coverage-trace-compares", 125 cl::desc("Tracing of CMP and similar instructions"), 126 cl::Hidden, cl::init(false)); 127 128 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 129 cl::desc("Tracing of DIV instructions"), 130 cl::Hidden, cl::init(false)); 131 132 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads", 133 cl::desc("Tracing of load instructions"), 134 cl::Hidden, cl::init(false)); 135 136 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 137 cl::desc("Tracing of store instructions"), 138 cl::Hidden, cl::init(false)); 139 140 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 141 cl::desc("Tracing of GEP instructions"), 142 cl::Hidden, cl::init(false)); 143 144 static cl::opt<bool> 145 ClPruneBlocks("sanitizer-coverage-prune-blocks", 146 cl::desc("Reduce the number of instrumented blocks"), 147 cl::Hidden, cl::init(true)); 148 149 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 150 cl::desc("max stack depth tracing"), 151 cl::Hidden, cl::init(false)); 152 153 static cl::opt<bool> 154 ClCollectCF("sanitizer-coverage-control-flow", 155 cl::desc("collect control flow for each function"), cl::Hidden, 156 cl::init(false)); 157 158 namespace { 159 160 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 161 SanitizerCoverageOptions Res; 162 switch (LegacyCoverageLevel) { 163 case 0: 164 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 165 break; 166 case 1: 167 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 168 break; 169 case 2: 170 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 171 break; 172 case 3: 173 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 174 break; 175 case 4: 176 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 177 Res.IndirectCalls = true; 178 break; 179 } 180 return Res; 181 } 182 183 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 184 // Sets CoverageType and IndirectCalls. 185 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 186 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 187 Options.IndirectCalls |= CLOpts.IndirectCalls; 188 Options.TraceCmp |= ClCMPTracing; 189 Options.TraceDiv |= ClDIVTracing; 190 Options.TraceGep |= ClGEPTracing; 191 Options.TracePC |= ClTracePC; 192 Options.TracePCGuard |= ClTracePCGuard; 193 Options.Inline8bitCounters |= ClInline8bitCounters; 194 Options.InlineBoolFlag |= ClInlineBoolFlag; 195 Options.PCTable |= ClCreatePCTable; 196 Options.NoPrune |= !ClPruneBlocks; 197 Options.StackDepth |= ClStackDepth; 198 Options.TraceLoads |= ClLoadTracing; 199 Options.TraceStores |= ClStoreTracing; 200 if (!Options.TracePCGuard && !Options.TracePC && 201 !Options.Inline8bitCounters && !Options.StackDepth && 202 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 203 Options.TracePCGuard = true; // TracePCGuard is default. 204 Options.CollectControlFlow |= ClCollectCF; 205 return Options; 206 } 207 208 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>; 209 using PostDomTreeCallback = 210 function_ref<const PostDominatorTree *(Function &F)>; 211 212 class ModuleSanitizerCoverage { 213 public: 214 ModuleSanitizerCoverage( 215 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 216 const SpecialCaseList *Allowlist = nullptr, 217 const SpecialCaseList *Blocklist = nullptr) 218 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 219 Blocklist(Blocklist) {} 220 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 221 PostDomTreeCallback PDTCallback); 222 223 private: 224 void createFunctionControlFlow(Function &F); 225 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 226 PostDomTreeCallback PDTCallback); 227 void InjectCoverageForIndirectCalls(Function &F, 228 ArrayRef<Instruction *> IndirCalls); 229 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 230 void InjectTraceForDiv(Function &F, 231 ArrayRef<BinaryOperator *> DivTraceTargets); 232 void InjectTraceForGep(Function &F, 233 ArrayRef<GetElementPtrInst *> GepTraceTargets); 234 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 235 ArrayRef<StoreInst *> Stores); 236 void InjectTraceForSwitch(Function &F, 237 ArrayRef<Instruction *> SwitchTraceTargets); 238 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 239 bool IsLeafFunc = true); 240 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 241 Function &F, Type *Ty, 242 const char *Section); 243 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 244 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 245 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 246 bool IsLeafFunc = true); 247 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 248 const char *InitFunctionName, Type *Ty, 249 const char *Section); 250 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 251 Type *Ty); 252 253 void SetNoSanitizeMetadata(Instruction *I) { 254 I->setMetadata(LLVMContext::MD_nosanitize, MDNode::get(*C, std::nullopt)); 255 } 256 257 std::string getSectionName(const std::string &Section) const; 258 std::string getSectionStart(const std::string &Section) const; 259 std::string getSectionEnd(const std::string &Section) const; 260 FunctionCallee SanCovTracePCIndir; 261 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 262 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 263 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 264 std::array<FunctionCallee, 5> SanCovLoadFunction; 265 std::array<FunctionCallee, 5> SanCovStoreFunction; 266 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 267 FunctionCallee SanCovTraceGepFunction; 268 FunctionCallee SanCovTraceSwitchFunction; 269 GlobalVariable *SanCovLowestStack; 270 Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, 271 *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, 272 *Int1PtrTy; 273 Module *CurModule; 274 std::string CurModuleUniqueId; 275 Triple TargetTriple; 276 LLVMContext *C; 277 const DataLayout *DL; 278 279 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 280 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 281 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 282 GlobalVariable *FunctionPCsArray; // for pc-table. 283 GlobalVariable *FunctionCFsArray; // for control flow table 284 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 285 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 286 287 SanitizerCoverageOptions Options; 288 289 const SpecialCaseList *Allowlist; 290 const SpecialCaseList *Blocklist; 291 }; 292 } // namespace 293 294 PreservedAnalyses SanitizerCoveragePass::run(Module &M, 295 ModuleAnalysisManager &MAM) { 296 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 297 Blocklist.get()); 298 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 299 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * { 300 return &FAM.getResult<DominatorTreeAnalysis>(F); 301 }; 302 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * { 303 return &FAM.getResult<PostDominatorTreeAnalysis>(F); 304 }; 305 if (!ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 306 return PreservedAnalyses::all(); 307 308 PreservedAnalyses PA = PreservedAnalyses::none(); 309 // GlobalsAA is considered stateless and does not get invalidated unless 310 // explicitly invalidated; PreservedAnalyses::none() is not enough. Sanitizers 311 // make changes that require GlobalsAA to be invalidated. 312 PA.abandon<GlobalsAA>(); 313 return PA; 314 } 315 316 std::pair<Value *, Value *> 317 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 318 Type *Ty) { 319 // Use ExternalWeak so that if all sections are discarded due to section 320 // garbage collection, the linker will not report undefined symbol errors. 321 // Windows defines the start/stop symbols in compiler-rt so no need for 322 // ExternalWeak. 323 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 324 ? GlobalVariable::ExternalLinkage 325 : GlobalVariable::ExternalWeakLinkage; 326 GlobalVariable *SecStart = 327 new GlobalVariable(M, Ty, false, Linkage, nullptr, 328 getSectionStart(Section)); 329 SecStart->setVisibility(GlobalValue::HiddenVisibility); 330 GlobalVariable *SecEnd = 331 new GlobalVariable(M, Ty, false, Linkage, nullptr, 332 getSectionEnd(Section)); 333 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 334 IRBuilder<> IRB(M.getContext()); 335 if (!TargetTriple.isOSBinFormatCOFF()) 336 return std::make_pair(SecStart, SecEnd); 337 338 // Account for the fact that on windows-msvc __start_* symbols actually 339 // point to a uint64_t before the start of the array. 340 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); 341 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, 342 ConstantInt::get(IntptrTy, sizeof(uint64_t))); 343 return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)), 344 SecEnd); 345 } 346 347 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 348 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 349 const char *Section) { 350 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 351 auto SecStart = SecStartEnd.first; 352 auto SecEnd = SecStartEnd.second; 353 Function *CtorFunc; 354 Type *PtrTy = PointerType::getUnqual(Ty); 355 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 356 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 357 assert(CtorFunc->getName() == CtorName); 358 359 if (TargetTriple.supportsCOMDAT()) { 360 // Use comdat to dedup CtorFunc. 361 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 362 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 363 } else { 364 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 365 } 366 367 if (TargetTriple.isOSBinFormatCOFF()) { 368 // In COFF files, if the contructors are set as COMDAT (they are because 369 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 370 // functions and data) is used, the constructors get stripped. To prevent 371 // this, give the constructors weak ODR linkage and ensure the linker knows 372 // to include the sancov constructor. This way the linker can deduplicate 373 // the constructors but always leave one copy. 374 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 375 } 376 return CtorFunc; 377 } 378 379 bool ModuleSanitizerCoverage::instrumentModule( 380 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 381 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 382 return false; 383 if (Allowlist && 384 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 385 return false; 386 if (Blocklist && 387 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 388 return false; 389 C = &(M.getContext()); 390 DL = &M.getDataLayout(); 391 CurModule = &M; 392 CurModuleUniqueId = getUniqueModuleId(CurModule); 393 TargetTriple = Triple(M.getTargetTriple()); 394 FunctionGuardArray = nullptr; 395 Function8bitCounterArray = nullptr; 396 FunctionBoolArray = nullptr; 397 FunctionPCsArray = nullptr; 398 FunctionCFsArray = nullptr; 399 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 400 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 401 Type *VoidTy = Type::getVoidTy(*C); 402 IRBuilder<> IRB(*C); 403 Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty()); 404 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 405 Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty()); 406 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 407 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 408 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty()); 409 Int64Ty = IRB.getInt64Ty(); 410 Int32Ty = IRB.getInt32Ty(); 411 Int16Ty = IRB.getInt16Ty(); 412 Int8Ty = IRB.getInt8Ty(); 413 Int1Ty = IRB.getInt1Ty(); 414 415 SanCovTracePCIndir = 416 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 417 // Make sure smaller parameters are zero-extended to i64 if required by the 418 // target ABI. 419 AttributeList SanCovTraceCmpZeroExtAL; 420 SanCovTraceCmpZeroExtAL = 421 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 422 SanCovTraceCmpZeroExtAL = 423 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 424 425 SanCovTraceCmpFunction[0] = 426 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 427 IRB.getInt8Ty(), IRB.getInt8Ty()); 428 SanCovTraceCmpFunction[1] = 429 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 430 IRB.getInt16Ty(), IRB.getInt16Ty()); 431 SanCovTraceCmpFunction[2] = 432 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 433 IRB.getInt32Ty(), IRB.getInt32Ty()); 434 SanCovTraceCmpFunction[3] = 435 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 436 437 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 438 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 439 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 440 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 441 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 442 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 443 SanCovTraceConstCmpFunction[3] = 444 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 445 446 // Loads. 447 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy); 448 SanCovLoadFunction[1] = 449 M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy); 450 SanCovLoadFunction[2] = 451 M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy); 452 SanCovLoadFunction[3] = 453 M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy); 454 SanCovLoadFunction[4] = 455 M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy); 456 // Stores. 457 SanCovStoreFunction[0] = 458 M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy); 459 SanCovStoreFunction[1] = 460 M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy); 461 SanCovStoreFunction[2] = 462 M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy); 463 SanCovStoreFunction[3] = 464 M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy); 465 SanCovStoreFunction[4] = 466 M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy); 467 468 { 469 AttributeList AL; 470 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 471 SanCovTraceDivFunction[0] = 472 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 473 } 474 SanCovTraceDivFunction[1] = 475 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 476 SanCovTraceGepFunction = 477 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 478 SanCovTraceSwitchFunction = 479 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); 480 481 Constant *SanCovLowestStackConstant = 482 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 483 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 484 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 485 C->emitError(StringRef("'") + SanCovLowestStackName + 486 "' should not be declared by the user"); 487 return true; 488 } 489 SanCovLowestStack->setThreadLocalMode( 490 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 491 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 492 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 493 494 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 495 SanCovTracePCGuard = 496 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); 497 498 for (auto &F : M) 499 instrumentFunction(F, DTCallback, PDTCallback); 500 501 Function *Ctor = nullptr; 502 503 if (FunctionGuardArray) 504 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 505 SanCovTracePCGuardInitName, Int32Ty, 506 SanCovGuardsSectionName); 507 if (Function8bitCounterArray) 508 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 509 SanCov8bitCountersInitName, Int8Ty, 510 SanCovCountersSectionName); 511 if (FunctionBoolArray) { 512 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 513 SanCovBoolFlagInitName, Int1Ty, 514 SanCovBoolFlagSectionName); 515 } 516 if (Ctor && Options.PCTable) { 517 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 518 FunctionCallee InitFunction = declareSanitizerInitFunction( 519 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 520 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 521 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 522 } 523 524 if (Ctor && Options.CollectControlFlow) { 525 auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrTy); 526 FunctionCallee InitFunction = declareSanitizerInitFunction( 527 M, SanCovCFsInitName, {IntptrPtrTy, IntptrPtrTy}); 528 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 529 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 530 } 531 532 appendToUsed(M, GlobalsToAppendToUsed); 533 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 534 return true; 535 } 536 537 // True if block has successors and it dominates all of them. 538 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 539 if (succ_empty(BB)) 540 return false; 541 542 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 543 return DT->dominates(BB, SUCC); 544 }); 545 } 546 547 // True if block has predecessors and it postdominates all of them. 548 static bool isFullPostDominator(const BasicBlock *BB, 549 const PostDominatorTree *PDT) { 550 if (pred_empty(BB)) 551 return false; 552 553 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 554 return PDT->dominates(BB, PRED); 555 }); 556 } 557 558 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 559 const DominatorTree *DT, 560 const PostDominatorTree *PDT, 561 const SanitizerCoverageOptions &Options) { 562 // Don't insert coverage for blocks containing nothing but unreachable: we 563 // will never call __sanitizer_cov() for them, so counting them in 564 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 565 // percentage. Also, unreachable instructions frequently have no debug 566 // locations. 567 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 568 return false; 569 570 // Don't insert coverage into blocks without a valid insertion point 571 // (catchswitch blocks). 572 if (BB->getFirstInsertionPt() == BB->end()) 573 return false; 574 575 if (Options.NoPrune || &F.getEntryBlock() == BB) 576 return true; 577 578 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 579 &F.getEntryBlock() != BB) 580 return false; 581 582 // Do not instrument full dominators, or full post-dominators with multiple 583 // predecessors. 584 return !isFullDominator(BB, DT) 585 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 586 } 587 588 589 // Returns true iff From->To is a backedge. 590 // A twist here is that we treat From->To as a backedge if 591 // * To dominates From or 592 // * To->UniqueSuccessor dominates From 593 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 594 const DominatorTree *DT) { 595 if (DT->dominates(To, From)) 596 return true; 597 if (auto Next = To->getUniqueSuccessor()) 598 if (DT->dominates(Next, From)) 599 return true; 600 return false; 601 } 602 603 // Prunes uninteresting Cmp instrumentation: 604 // * CMP instructions that feed into loop backedge branch. 605 // 606 // Note that Cmp pruning is controlled by the same flag as the 607 // BB pruning. 608 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, 609 const SanitizerCoverageOptions &Options) { 610 if (!Options.NoPrune) 611 if (CMP->hasOneUse()) 612 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 613 for (BasicBlock *B : BR->successors()) 614 if (IsBackEdge(BR->getParent(), B, DT)) 615 return false; 616 return true; 617 } 618 619 void ModuleSanitizerCoverage::instrumentFunction( 620 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 621 if (F.empty()) 622 return; 623 if (F.getName().find(".module_ctor") != std::string::npos) 624 return; // Should not instrument sanitizer init functions. 625 if (F.getName().startswith("__sanitizer_")) 626 return; // Don't instrument __sanitizer_* callbacks. 627 // Don't touch available_externally functions, their actual body is elewhere. 628 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 629 return; 630 // Don't instrument MSVC CRT configuration helpers. They may run before normal 631 // initialization. 632 if (F.getName() == "__local_stdio_printf_options" || 633 F.getName() == "__local_stdio_scanf_options") 634 return; 635 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 636 return; 637 // Don't instrument functions using SEH for now. Splitting basic blocks like 638 // we do for coverage breaks WinEHPrepare. 639 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 640 if (F.hasPersonalityFn() && 641 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 642 return; 643 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 644 return; 645 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 646 return; 647 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 648 return; 649 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 650 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 651 SmallVector<Instruction *, 8> IndirCalls; 652 SmallVector<BasicBlock *, 16> BlocksToInstrument; 653 SmallVector<Instruction *, 8> CmpTraceTargets; 654 SmallVector<Instruction *, 8> SwitchTraceTargets; 655 SmallVector<BinaryOperator *, 8> DivTraceTargets; 656 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 657 SmallVector<LoadInst *, 8> Loads; 658 SmallVector<StoreInst *, 8> Stores; 659 660 const DominatorTree *DT = DTCallback(F); 661 const PostDominatorTree *PDT = PDTCallback(F); 662 bool IsLeafFunc = true; 663 664 for (auto &BB : F) { 665 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 666 BlocksToInstrument.push_back(&BB); 667 for (auto &Inst : BB) { 668 if (Options.IndirectCalls) { 669 CallBase *CB = dyn_cast<CallBase>(&Inst); 670 if (CB && CB->isIndirectCall()) 671 IndirCalls.push_back(&Inst); 672 } 673 if (Options.TraceCmp) { 674 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 675 if (IsInterestingCmp(CMP, DT, Options)) 676 CmpTraceTargets.push_back(&Inst); 677 if (isa<SwitchInst>(&Inst)) 678 SwitchTraceTargets.push_back(&Inst); 679 } 680 if (Options.TraceDiv) 681 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 682 if (BO->getOpcode() == Instruction::SDiv || 683 BO->getOpcode() == Instruction::UDiv) 684 DivTraceTargets.push_back(BO); 685 if (Options.TraceGep) 686 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 687 GepTraceTargets.push_back(GEP); 688 if (Options.TraceLoads) 689 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 690 Loads.push_back(LI); 691 if (Options.TraceStores) 692 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 693 Stores.push_back(SI); 694 if (Options.StackDepth) 695 if (isa<InvokeInst>(Inst) || 696 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 697 IsLeafFunc = false; 698 } 699 } 700 701 if (Options.CollectControlFlow) 702 createFunctionControlFlow(F); 703 704 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 705 InjectCoverageForIndirectCalls(F, IndirCalls); 706 InjectTraceForCmp(F, CmpTraceTargets); 707 InjectTraceForSwitch(F, SwitchTraceTargets); 708 InjectTraceForDiv(F, DivTraceTargets); 709 InjectTraceForGep(F, GepTraceTargets); 710 InjectTraceForLoadsAndStores(F, Loads, Stores); 711 } 712 713 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 714 size_t NumElements, Function &F, Type *Ty, const char *Section) { 715 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 716 auto Array = new GlobalVariable( 717 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 718 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 719 720 if (TargetTriple.supportsCOMDAT() && 721 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 722 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 723 Array->setComdat(Comdat); 724 Array->setSection(getSectionName(Section)); 725 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue())); 726 727 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 728 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 729 // section(s) as a unit, so we conservatively retain all unconditionally in 730 // the compiler. 731 // 732 // With comdat (COFF/ELF), the linker can guarantee the associated sections 733 // will be retained or discarded as a unit, so llvm.compiler.used is 734 // sufficient. Otherwise, conservatively make all of them retained by the 735 // linker. 736 if (Array->hasComdat()) 737 GlobalsToAppendToCompilerUsed.push_back(Array); 738 else 739 GlobalsToAppendToUsed.push_back(Array); 740 741 return Array; 742 } 743 744 GlobalVariable * 745 ModuleSanitizerCoverage::CreatePCArray(Function &F, 746 ArrayRef<BasicBlock *> AllBlocks) { 747 size_t N = AllBlocks.size(); 748 assert(N); 749 SmallVector<Constant *, 32> PCs; 750 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 751 for (size_t i = 0; i < N; i++) { 752 if (&F.getEntryBlock() == AllBlocks[i]) { 753 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 754 PCs.push_back((Constant *)IRB.CreateIntToPtr( 755 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 756 } else { 757 PCs.push_back((Constant *)IRB.CreatePointerCast( 758 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 759 PCs.push_back(Constant::getNullValue(IntptrPtrTy)); 760 } 761 } 762 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 763 SanCovPCsSectionName); 764 PCArray->setInitializer( 765 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 766 PCArray->setConstant(true); 767 768 return PCArray; 769 } 770 771 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 772 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 773 if (Options.TracePCGuard) 774 FunctionGuardArray = CreateFunctionLocalArrayInSection( 775 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 776 777 if (Options.Inline8bitCounters) 778 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 779 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 780 if (Options.InlineBoolFlag) 781 FunctionBoolArray = CreateFunctionLocalArrayInSection( 782 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 783 784 if (Options.PCTable) 785 FunctionPCsArray = CreatePCArray(F, AllBlocks); 786 } 787 788 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 789 ArrayRef<BasicBlock *> AllBlocks, 790 bool IsLeafFunc) { 791 if (AllBlocks.empty()) return false; 792 CreateFunctionLocalArrays(F, AllBlocks); 793 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 794 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 795 return true; 796 } 797 798 // On every indirect call we call a run-time function 799 // __sanitizer_cov_indir_call* with two parameters: 800 // - callee address, 801 // - global cache array that contains CacheSize pointers (zero-initialized). 802 // The cache is used to speed up recording the caller-callee pairs. 803 // The address of the caller is passed implicitly via caller PC. 804 // CacheSize is encoded in the name of the run-time function. 805 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 806 Function &F, ArrayRef<Instruction *> IndirCalls) { 807 if (IndirCalls.empty()) 808 return; 809 assert(Options.TracePC || Options.TracePCGuard || 810 Options.Inline8bitCounters || Options.InlineBoolFlag); 811 for (auto *I : IndirCalls) { 812 IRBuilder<> IRB(I); 813 CallBase &CB = cast<CallBase>(*I); 814 Value *Callee = CB.getCalledOperand(); 815 if (isa<InlineAsm>(Callee)) 816 continue; 817 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 818 } 819 } 820 821 // For every switch statement we insert a call: 822 // __sanitizer_cov_trace_switch(CondValue, 823 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 824 825 void ModuleSanitizerCoverage::InjectTraceForSwitch( 826 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 827 for (auto *I : SwitchTraceTargets) { 828 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 829 IRBuilder<> IRB(I); 830 SmallVector<Constant *, 16> Initializers; 831 Value *Cond = SI->getCondition(); 832 if (Cond->getType()->getScalarSizeInBits() > 833 Int64Ty->getScalarSizeInBits()) 834 continue; 835 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 836 Initializers.push_back( 837 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 838 if (Cond->getType()->getScalarSizeInBits() < 839 Int64Ty->getScalarSizeInBits()) 840 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 841 for (auto It : SI->cases()) { 842 Constant *C = It.getCaseValue(); 843 if (C->getType()->getScalarSizeInBits() < 844 Int64Ty->getScalarSizeInBits()) 845 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 846 Initializers.push_back(C); 847 } 848 llvm::sort(drop_begin(Initializers, 2), 849 [](const Constant *A, const Constant *B) { 850 return cast<ConstantInt>(A)->getLimitedValue() < 851 cast<ConstantInt>(B)->getLimitedValue(); 852 }); 853 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 854 GlobalVariable *GV = new GlobalVariable( 855 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 856 ConstantArray::get(ArrayOfInt64Ty, Initializers), 857 "__sancov_gen_cov_switch_values"); 858 IRB.CreateCall(SanCovTraceSwitchFunction, 859 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 860 } 861 } 862 } 863 864 void ModuleSanitizerCoverage::InjectTraceForDiv( 865 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 866 for (auto *BO : DivTraceTargets) { 867 IRBuilder<> IRB(BO); 868 Value *A1 = BO->getOperand(1); 869 if (isa<ConstantInt>(A1)) continue; 870 if (!A1->getType()->isIntegerTy()) 871 continue; 872 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 873 int CallbackIdx = TypeSize == 32 ? 0 : 874 TypeSize == 64 ? 1 : -1; 875 if (CallbackIdx < 0) continue; 876 auto Ty = Type::getIntNTy(*C, TypeSize); 877 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 878 {IRB.CreateIntCast(A1, Ty, true)}); 879 } 880 } 881 882 void ModuleSanitizerCoverage::InjectTraceForGep( 883 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 884 for (auto *GEP : GepTraceTargets) { 885 IRBuilder<> IRB(GEP); 886 for (Use &Idx : GEP->indices()) 887 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 888 IRB.CreateCall(SanCovTraceGepFunction, 889 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 890 } 891 } 892 893 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 894 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 895 auto CallbackIdx = [&](Type *ElementTy) -> int { 896 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 897 return TypeSize == 8 ? 0 898 : TypeSize == 16 ? 1 899 : TypeSize == 32 ? 2 900 : TypeSize == 64 ? 3 901 : TypeSize == 128 ? 4 902 : -1; 903 }; 904 Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy, 905 Int128PtrTy}; 906 for (auto *LI : Loads) { 907 IRBuilder<> IRB(LI); 908 auto Ptr = LI->getPointerOperand(); 909 int Idx = CallbackIdx(LI->getType()); 910 if (Idx < 0) 911 continue; 912 IRB.CreateCall(SanCovLoadFunction[Idx], 913 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 914 } 915 for (auto *SI : Stores) { 916 IRBuilder<> IRB(SI); 917 auto Ptr = SI->getPointerOperand(); 918 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 919 if (Idx < 0) 920 continue; 921 IRB.CreateCall(SanCovStoreFunction[Idx], 922 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 923 } 924 } 925 926 void ModuleSanitizerCoverage::InjectTraceForCmp( 927 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 928 for (auto *I : CmpTraceTargets) { 929 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 930 IRBuilder<> IRB(ICMP); 931 Value *A0 = ICMP->getOperand(0); 932 Value *A1 = ICMP->getOperand(1); 933 if (!A0->getType()->isIntegerTy()) 934 continue; 935 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 936 int CallbackIdx = TypeSize == 8 ? 0 : 937 TypeSize == 16 ? 1 : 938 TypeSize == 32 ? 2 : 939 TypeSize == 64 ? 3 : -1; 940 if (CallbackIdx < 0) continue; 941 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 942 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 943 bool FirstIsConst = isa<ConstantInt>(A0); 944 bool SecondIsConst = isa<ConstantInt>(A1); 945 // If both are const, then we don't need such a comparison. 946 if (FirstIsConst && SecondIsConst) continue; 947 // If only one is const, then make it the first callback argument. 948 if (FirstIsConst || SecondIsConst) { 949 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 950 if (SecondIsConst) 951 std::swap(A0, A1); 952 } 953 954 auto Ty = Type::getIntNTy(*C, TypeSize); 955 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 956 IRB.CreateIntCast(A1, Ty, true)}); 957 } 958 } 959 } 960 961 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 962 size_t Idx, 963 bool IsLeafFunc) { 964 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 965 bool IsEntryBB = &BB == &F.getEntryBlock(); 966 DebugLoc EntryLoc; 967 if (IsEntryBB) { 968 if (auto SP = F.getSubprogram()) 969 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 970 // Keep static allocas and llvm.localescape calls in the entry block. Even 971 // if we aren't splitting the block, it's nice for allocas to be before 972 // calls. 973 IP = PrepareToSplitEntryBlock(BB, IP); 974 } 975 976 InstrumentationIRBuilder IRB(&*IP); 977 if (EntryLoc) 978 IRB.SetCurrentDebugLocation(EntryLoc); 979 if (Options.TracePC) { 980 IRB.CreateCall(SanCovTracePC) 981 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 982 } 983 if (Options.TracePCGuard) { 984 auto GuardPtr = IRB.CreateIntToPtr( 985 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 986 ConstantInt::get(IntptrTy, Idx * 4)), 987 Int32PtrTy); 988 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 989 } 990 if (Options.Inline8bitCounters) { 991 auto CounterPtr = IRB.CreateGEP( 992 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 993 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 994 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 995 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 996 auto Store = IRB.CreateStore(Inc, CounterPtr); 997 SetNoSanitizeMetadata(Load); 998 SetNoSanitizeMetadata(Store); 999 } 1000 if (Options.InlineBoolFlag) { 1001 auto FlagPtr = IRB.CreateGEP( 1002 FunctionBoolArray->getValueType(), FunctionBoolArray, 1003 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 1004 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 1005 auto ThenTerm = 1006 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false); 1007 IRBuilder<> ThenIRB(ThenTerm); 1008 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 1009 SetNoSanitizeMetadata(Load); 1010 SetNoSanitizeMetadata(Store); 1011 } 1012 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 1013 // Check stack depth. If it's the deepest so far, record it. 1014 Module *M = F.getParent(); 1015 Function *GetFrameAddr = Intrinsic::getDeclaration( 1016 M, Intrinsic::frameaddress, 1017 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace())); 1018 auto FrameAddrPtr = 1019 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 1020 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1021 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1022 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1023 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 1024 IRBuilder<> ThenIRB(ThenTerm); 1025 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1026 SetNoSanitizeMetadata(LowestStack); 1027 SetNoSanitizeMetadata(Store); 1028 } 1029 } 1030 1031 std::string 1032 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1033 if (TargetTriple.isOSBinFormatCOFF()) { 1034 if (Section == SanCovCountersSectionName) 1035 return ".SCOV$CM"; 1036 if (Section == SanCovBoolFlagSectionName) 1037 return ".SCOV$BM"; 1038 if (Section == SanCovPCsSectionName) 1039 return ".SCOVP$M"; 1040 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1041 } 1042 if (TargetTriple.isOSBinFormatMachO()) 1043 return "__DATA,__" + Section; 1044 return "__" + Section; 1045 } 1046 1047 std::string 1048 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1049 if (TargetTriple.isOSBinFormatMachO()) 1050 return "\1section$start$__DATA$__" + Section; 1051 return "__start___" + Section; 1052 } 1053 1054 std::string 1055 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1056 if (TargetTriple.isOSBinFormatMachO()) 1057 return "\1section$end$__DATA$__" + Section; 1058 return "__stop___" + Section; 1059 } 1060 1061 void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) { 1062 SmallVector<Constant *, 32> CFs; 1063 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 1064 1065 for (auto &BB : F) { 1066 // blockaddress can not be used on function's entry block. 1067 if (&BB == &F.getEntryBlock()) 1068 CFs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 1069 else 1070 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(&BB), 1071 IntptrPtrTy)); 1072 1073 for (auto SuccBB : successors(&BB)) { 1074 assert(SuccBB != &F.getEntryBlock()); 1075 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(SuccBB), 1076 IntptrPtrTy)); 1077 } 1078 1079 CFs.push_back((Constant *)Constant::getNullValue(IntptrPtrTy)); 1080 1081 for (auto &Inst : BB) { 1082 if (CallBase *CB = dyn_cast<CallBase>(&Inst)) { 1083 if (CB->isIndirectCall()) { 1084 // TODO(navidem): handle indirect calls, for now mark its existence. 1085 CFs.push_back((Constant *)IRB.CreateIntToPtr( 1086 ConstantInt::get(IntptrTy, -1), IntptrPtrTy)); 1087 } else { 1088 auto CalledF = CB->getCalledFunction(); 1089 if (CalledF && !CalledF->isIntrinsic()) 1090 CFs.push_back( 1091 (Constant *)IRB.CreatePointerCast(CalledF, IntptrPtrTy)); 1092 } 1093 } 1094 } 1095 1096 CFs.push_back((Constant *)Constant::getNullValue(IntptrPtrTy)); 1097 } 1098 1099 FunctionCFsArray = CreateFunctionLocalArrayInSection( 1100 CFs.size(), F, IntptrPtrTy, SanCovCFsSectionName); 1101 FunctionCFsArray->setInitializer( 1102 ConstantArray::get(ArrayType::get(IntptrPtrTy, CFs.size()), CFs)); 1103 FunctionCFsArray->setConstant(true); 1104 } 1105