1 //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // Coverage instrumentation done on LLVM IR level, works with Sanitizers. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h" 14 #include "llvm/ADT/ArrayRef.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/Analysis/GlobalsModRef.h" 17 #include "llvm/Analysis/PostDominators.h" 18 #include "llvm/IR/Constant.h" 19 #include "llvm/IR/DataLayout.h" 20 #include "llvm/IR/Dominators.h" 21 #include "llvm/IR/EHPersonalities.h" 22 #include "llvm/IR/Function.h" 23 #include "llvm/IR/GlobalVariable.h" 24 #include "llvm/IR/IRBuilder.h" 25 #include "llvm/IR/IntrinsicInst.h" 26 #include "llvm/IR/Intrinsics.h" 27 #include "llvm/IR/LLVMContext.h" 28 #include "llvm/IR/Module.h" 29 #include "llvm/IR/Type.h" 30 #include "llvm/Support/CommandLine.h" 31 #include "llvm/Support/SpecialCaseList.h" 32 #include "llvm/Support/VirtualFileSystem.h" 33 #include "llvm/TargetParser/Triple.h" 34 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 35 #include "llvm/Transforms/Utils/ModuleUtils.h" 36 37 using namespace llvm; 38 39 #define DEBUG_TYPE "sancov" 40 41 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir"; 42 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc"; 43 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1"; 44 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2"; 45 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4"; 46 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8"; 47 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1"; 48 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2"; 49 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4"; 50 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8"; 51 const char SanCovLoad1[] = "__sanitizer_cov_load1"; 52 const char SanCovLoad2[] = "__sanitizer_cov_load2"; 53 const char SanCovLoad4[] = "__sanitizer_cov_load4"; 54 const char SanCovLoad8[] = "__sanitizer_cov_load8"; 55 const char SanCovLoad16[] = "__sanitizer_cov_load16"; 56 const char SanCovStore1[] = "__sanitizer_cov_store1"; 57 const char SanCovStore2[] = "__sanitizer_cov_store2"; 58 const char SanCovStore4[] = "__sanitizer_cov_store4"; 59 const char SanCovStore8[] = "__sanitizer_cov_store8"; 60 const char SanCovStore16[] = "__sanitizer_cov_store16"; 61 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4"; 62 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8"; 63 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep"; 64 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch"; 65 const char SanCovModuleCtorTracePcGuardName[] = 66 "sancov.module_ctor_trace_pc_guard"; 67 const char SanCovModuleCtor8bitCountersName[] = 68 "sancov.module_ctor_8bit_counters"; 69 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag"; 70 static const uint64_t SanCtorAndDtorPriority = 2; 71 72 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard"; 73 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init"; 74 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init"; 75 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init"; 76 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init"; 77 const char SanCovCFsInitName[] = "__sanitizer_cov_cfs_init"; 78 79 const char SanCovGuardsSectionName[] = "sancov_guards"; 80 const char SanCovCountersSectionName[] = "sancov_cntrs"; 81 const char SanCovBoolFlagSectionName[] = "sancov_bools"; 82 const char SanCovPCsSectionName[] = "sancov_pcs"; 83 const char SanCovCFsSectionName[] = "sancov_cfs"; 84 85 const char SanCovLowestStackName[] = "__sancov_lowest_stack"; 86 87 static cl::opt<int> ClCoverageLevel( 88 "sanitizer-coverage-level", 89 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 90 "3: all blocks and critical edges"), 91 cl::Hidden, cl::init(0)); 92 93 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 94 cl::desc("Experimental pc tracing"), cl::Hidden, 95 cl::init(false)); 96 97 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 98 cl::desc("pc tracing with a guard"), 99 cl::Hidden, cl::init(false)); 100 101 // If true, we create a global variable that contains PCs of all instrumented 102 // BBs, put this global into a named section, and pass this section's bounds 103 // to __sanitizer_cov_pcs_init. 104 // This way the coverage instrumentation does not need to acquire the PCs 105 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and 106 // inline-bool-flag. 107 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 108 cl::desc("create a static PC table"), 109 cl::Hidden, cl::init(false)); 110 111 static cl::opt<bool> 112 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 113 cl::desc("increments 8-bit counter for every edge"), 114 cl::Hidden, cl::init(false)); 115 116 static cl::opt<bool> 117 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag", 118 cl::desc("sets a boolean flag for every edge"), cl::Hidden, 119 cl::init(false)); 120 121 static cl::opt<bool> 122 ClCMPTracing("sanitizer-coverage-trace-compares", 123 cl::desc("Tracing of CMP and similar instructions"), 124 cl::Hidden, cl::init(false)); 125 126 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 127 cl::desc("Tracing of DIV instructions"), 128 cl::Hidden, cl::init(false)); 129 130 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads", 131 cl::desc("Tracing of load instructions"), 132 cl::Hidden, cl::init(false)); 133 134 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores", 135 cl::desc("Tracing of store instructions"), 136 cl::Hidden, cl::init(false)); 137 138 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 139 cl::desc("Tracing of GEP instructions"), 140 cl::Hidden, cl::init(false)); 141 142 static cl::opt<bool> 143 ClPruneBlocks("sanitizer-coverage-prune-blocks", 144 cl::desc("Reduce the number of instrumented blocks"), 145 cl::Hidden, cl::init(true)); 146 147 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 148 cl::desc("max stack depth tracing"), 149 cl::Hidden, cl::init(false)); 150 151 static cl::opt<bool> 152 ClCollectCF("sanitizer-coverage-control-flow", 153 cl::desc("collect control flow for each function"), cl::Hidden, 154 cl::init(false)); 155 156 namespace { 157 158 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 159 SanitizerCoverageOptions Res; 160 switch (LegacyCoverageLevel) { 161 case 0: 162 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 163 break; 164 case 1: 165 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 166 break; 167 case 2: 168 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 169 break; 170 case 3: 171 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 172 break; 173 case 4: 174 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 175 Res.IndirectCalls = true; 176 break; 177 } 178 return Res; 179 } 180 181 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 182 // Sets CoverageType and IndirectCalls. 183 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 184 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 185 Options.IndirectCalls |= CLOpts.IndirectCalls; 186 Options.TraceCmp |= ClCMPTracing; 187 Options.TraceDiv |= ClDIVTracing; 188 Options.TraceGep |= ClGEPTracing; 189 Options.TracePC |= ClTracePC; 190 Options.TracePCGuard |= ClTracePCGuard; 191 Options.Inline8bitCounters |= ClInline8bitCounters; 192 Options.InlineBoolFlag |= ClInlineBoolFlag; 193 Options.PCTable |= ClCreatePCTable; 194 Options.NoPrune |= !ClPruneBlocks; 195 Options.StackDepth |= ClStackDepth; 196 Options.TraceLoads |= ClLoadTracing; 197 Options.TraceStores |= ClStoreTracing; 198 if (!Options.TracePCGuard && !Options.TracePC && 199 !Options.Inline8bitCounters && !Options.StackDepth && 200 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores) 201 Options.TracePCGuard = true; // TracePCGuard is default. 202 Options.CollectControlFlow |= ClCollectCF; 203 return Options; 204 } 205 206 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>; 207 using PostDomTreeCallback = 208 function_ref<const PostDominatorTree *(Function &F)>; 209 210 class ModuleSanitizerCoverage { 211 public: 212 ModuleSanitizerCoverage( 213 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(), 214 const SpecialCaseList *Allowlist = nullptr, 215 const SpecialCaseList *Blocklist = nullptr) 216 : Options(OverrideFromCL(Options)), Allowlist(Allowlist), 217 Blocklist(Blocklist) {} 218 bool instrumentModule(Module &M, DomTreeCallback DTCallback, 219 PostDomTreeCallback PDTCallback); 220 221 private: 222 void createFunctionControlFlow(Function &F); 223 void instrumentFunction(Function &F, DomTreeCallback DTCallback, 224 PostDomTreeCallback PDTCallback); 225 void InjectCoverageForIndirectCalls(Function &F, 226 ArrayRef<Instruction *> IndirCalls); 227 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 228 void InjectTraceForDiv(Function &F, 229 ArrayRef<BinaryOperator *> DivTraceTargets); 230 void InjectTraceForGep(Function &F, 231 ArrayRef<GetElementPtrInst *> GepTraceTargets); 232 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads, 233 ArrayRef<StoreInst *> Stores); 234 void InjectTraceForSwitch(Function &F, 235 ArrayRef<Instruction *> SwitchTraceTargets); 236 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 237 bool IsLeafFunc = true); 238 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 239 Function &F, Type *Ty, 240 const char *Section); 241 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 242 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 243 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 244 bool IsLeafFunc = true); 245 Function *CreateInitCallsForSections(Module &M, const char *CtorName, 246 const char *InitFunctionName, Type *Ty, 247 const char *Section); 248 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, 249 Type *Ty); 250 251 std::string getSectionName(const std::string &Section) const; 252 std::string getSectionStart(const std::string &Section) const; 253 std::string getSectionEnd(const std::string &Section) const; 254 FunctionCallee SanCovTracePCIndir; 255 FunctionCallee SanCovTracePC, SanCovTracePCGuard; 256 std::array<FunctionCallee, 4> SanCovTraceCmpFunction; 257 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction; 258 std::array<FunctionCallee, 5> SanCovLoadFunction; 259 std::array<FunctionCallee, 5> SanCovStoreFunction; 260 std::array<FunctionCallee, 2> SanCovTraceDivFunction; 261 FunctionCallee SanCovTraceGepFunction; 262 FunctionCallee SanCovTraceSwitchFunction; 263 GlobalVariable *SanCovLowestStack; 264 Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, 265 *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, 266 *Int1PtrTy; 267 Module *CurModule; 268 std::string CurModuleUniqueId; 269 Triple TargetTriple; 270 LLVMContext *C; 271 const DataLayout *DL; 272 273 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 274 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 275 GlobalVariable *FunctionBoolArray; // for inline-bool-flag. 276 GlobalVariable *FunctionPCsArray; // for pc-table. 277 GlobalVariable *FunctionCFsArray; // for control flow table 278 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 279 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; 280 281 SanitizerCoverageOptions Options; 282 283 const SpecialCaseList *Allowlist; 284 const SpecialCaseList *Blocklist; 285 }; 286 } // namespace 287 288 PreservedAnalyses SanitizerCoveragePass::run(Module &M, 289 ModuleAnalysisManager &MAM) { 290 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(), 291 Blocklist.get()); 292 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 293 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * { 294 return &FAM.getResult<DominatorTreeAnalysis>(F); 295 }; 296 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * { 297 return &FAM.getResult<PostDominatorTreeAnalysis>(F); 298 }; 299 if (!ModuleSancov.instrumentModule(M, DTCallback, PDTCallback)) 300 return PreservedAnalyses::all(); 301 302 PreservedAnalyses PA = PreservedAnalyses::none(); 303 // GlobalsAA is considered stateless and does not get invalidated unless 304 // explicitly invalidated; PreservedAnalyses::none() is not enough. Sanitizers 305 // make changes that require GlobalsAA to be invalidated. 306 PA.abandon<GlobalsAA>(); 307 return PA; 308 } 309 310 std::pair<Value *, Value *> 311 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section, 312 Type *Ty) { 313 // Use ExternalWeak so that if all sections are discarded due to section 314 // garbage collection, the linker will not report undefined symbol errors. 315 // Windows defines the start/stop symbols in compiler-rt so no need for 316 // ExternalWeak. 317 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF() 318 ? GlobalVariable::ExternalLinkage 319 : GlobalVariable::ExternalWeakLinkage; 320 GlobalVariable *SecStart = 321 new GlobalVariable(M, Ty, false, Linkage, nullptr, 322 getSectionStart(Section)); 323 SecStart->setVisibility(GlobalValue::HiddenVisibility); 324 GlobalVariable *SecEnd = 325 new GlobalVariable(M, Ty, false, Linkage, nullptr, 326 getSectionEnd(Section)); 327 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 328 IRBuilder<> IRB(M.getContext()); 329 if (!TargetTriple.isOSBinFormatCOFF()) 330 return std::make_pair(SecStart, SecEnd); 331 332 // Account for the fact that on windows-msvc __start_* symbols actually 333 // point to a uint64_t before the start of the array. 334 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); 335 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, 336 ConstantInt::get(IntptrTy, sizeof(uint64_t))); 337 return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)), 338 SecEnd); 339 } 340 341 Function *ModuleSanitizerCoverage::CreateInitCallsForSections( 342 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, 343 const char *Section) { 344 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 345 auto SecStart = SecStartEnd.first; 346 auto SecEnd = SecStartEnd.second; 347 Function *CtorFunc; 348 Type *PtrTy = PointerType::getUnqual(Ty); 349 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 350 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd}); 351 assert(CtorFunc->getName() == CtorName); 352 353 if (TargetTriple.supportsCOMDAT()) { 354 // Use comdat to dedup CtorFunc. 355 CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); 356 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 357 } else { 358 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 359 } 360 361 if (TargetTriple.isOSBinFormatCOFF()) { 362 // In COFF files, if the contructors are set as COMDAT (they are because 363 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced 364 // functions and data) is used, the constructors get stripped. To prevent 365 // this, give the constructors weak ODR linkage and ensure the linker knows 366 // to include the sancov constructor. This way the linker can deduplicate 367 // the constructors but always leave one copy. 368 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); 369 } 370 return CtorFunc; 371 } 372 373 bool ModuleSanitizerCoverage::instrumentModule( 374 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 375 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 376 return false; 377 if (Allowlist && 378 !Allowlist->inSection("coverage", "src", M.getSourceFileName())) 379 return false; 380 if (Blocklist && 381 Blocklist->inSection("coverage", "src", M.getSourceFileName())) 382 return false; 383 C = &(M.getContext()); 384 DL = &M.getDataLayout(); 385 CurModule = &M; 386 CurModuleUniqueId = getUniqueModuleId(CurModule); 387 TargetTriple = Triple(M.getTargetTriple()); 388 FunctionGuardArray = nullptr; 389 Function8bitCounterArray = nullptr; 390 FunctionBoolArray = nullptr; 391 FunctionPCsArray = nullptr; 392 FunctionCFsArray = nullptr; 393 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 394 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 395 Type *VoidTy = Type::getVoidTy(*C); 396 IRBuilder<> IRB(*C); 397 Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty()); 398 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 399 Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty()); 400 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 401 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 402 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty()); 403 Int64Ty = IRB.getInt64Ty(); 404 Int32Ty = IRB.getInt32Ty(); 405 Int16Ty = IRB.getInt16Ty(); 406 Int8Ty = IRB.getInt8Ty(); 407 Int1Ty = IRB.getInt1Ty(); 408 409 SanCovTracePCIndir = 410 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); 411 // Make sure smaller parameters are zero-extended to i64 if required by the 412 // target ABI. 413 AttributeList SanCovTraceCmpZeroExtAL; 414 SanCovTraceCmpZeroExtAL = 415 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); 416 SanCovTraceCmpZeroExtAL = 417 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); 418 419 SanCovTraceCmpFunction[0] = 420 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, 421 IRB.getInt8Ty(), IRB.getInt8Ty()); 422 SanCovTraceCmpFunction[1] = 423 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, 424 IRB.getInt16Ty(), IRB.getInt16Ty()); 425 SanCovTraceCmpFunction[2] = 426 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, 427 IRB.getInt32Ty(), IRB.getInt32Ty()); 428 SanCovTraceCmpFunction[3] = 429 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); 430 431 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( 432 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); 433 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( 434 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); 435 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( 436 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); 437 SanCovTraceConstCmpFunction[3] = 438 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); 439 440 // Loads. 441 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy); 442 SanCovLoadFunction[1] = 443 M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy); 444 SanCovLoadFunction[2] = 445 M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy); 446 SanCovLoadFunction[3] = 447 M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy); 448 SanCovLoadFunction[4] = 449 M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy); 450 // Stores. 451 SanCovStoreFunction[0] = 452 M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy); 453 SanCovStoreFunction[1] = 454 M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy); 455 SanCovStoreFunction[2] = 456 M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy); 457 SanCovStoreFunction[3] = 458 M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy); 459 SanCovStoreFunction[4] = 460 M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy); 461 462 { 463 AttributeList AL; 464 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); 465 SanCovTraceDivFunction[0] = 466 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); 467 } 468 SanCovTraceDivFunction[1] = 469 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); 470 SanCovTraceGepFunction = 471 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); 472 SanCovTraceSwitchFunction = 473 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); 474 475 Constant *SanCovLowestStackConstant = 476 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 477 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); 478 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) { 479 C->emitError(StringRef("'") + SanCovLowestStackName + 480 "' should not be declared by the user"); 481 return true; 482 } 483 SanCovLowestStack->setThreadLocalMode( 484 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 485 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 486 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 487 488 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy); 489 SanCovTracePCGuard = 490 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); 491 492 for (auto &F : M) 493 instrumentFunction(F, DTCallback, PDTCallback); 494 495 Function *Ctor = nullptr; 496 497 if (FunctionGuardArray) 498 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, 499 SanCovTracePCGuardInitName, Int32Ty, 500 SanCovGuardsSectionName); 501 if (Function8bitCounterArray) 502 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, 503 SanCov8bitCountersInitName, Int8Ty, 504 SanCovCountersSectionName); 505 if (FunctionBoolArray) { 506 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName, 507 SanCovBoolFlagInitName, Int1Ty, 508 SanCovBoolFlagSectionName); 509 } 510 if (Ctor && Options.PCTable) { 511 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy); 512 FunctionCallee InitFunction = declareSanitizerInitFunction( 513 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 514 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 515 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 516 } 517 518 if (Ctor && Options.CollectControlFlow) { 519 auto SecStartEnd = CreateSecStartEnd(M, SanCovCFsSectionName, IntptrTy); 520 FunctionCallee InitFunction = declareSanitizerInitFunction( 521 M, SanCovCFsInitName, {IntptrPtrTy, IntptrPtrTy}); 522 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 523 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); 524 } 525 526 appendToUsed(M, GlobalsToAppendToUsed); 527 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); 528 return true; 529 } 530 531 // True if block has successors and it dominates all of them. 532 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 533 if (succ_empty(BB)) 534 return false; 535 536 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) { 537 return DT->dominates(BB, SUCC); 538 }); 539 } 540 541 // True if block has predecessors and it postdominates all of them. 542 static bool isFullPostDominator(const BasicBlock *BB, 543 const PostDominatorTree *PDT) { 544 if (pred_empty(BB)) 545 return false; 546 547 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) { 548 return PDT->dominates(BB, PRED); 549 }); 550 } 551 552 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 553 const DominatorTree *DT, 554 const PostDominatorTree *PDT, 555 const SanitizerCoverageOptions &Options) { 556 // Don't insert coverage for blocks containing nothing but unreachable: we 557 // will never call __sanitizer_cov() for them, so counting them in 558 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 559 // percentage. Also, unreachable instructions frequently have no debug 560 // locations. 561 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime())) 562 return false; 563 564 // Don't insert coverage into blocks without a valid insertion point 565 // (catchswitch blocks). 566 if (BB->getFirstInsertionPt() == BB->end()) 567 return false; 568 569 if (Options.NoPrune || &F.getEntryBlock() == BB) 570 return true; 571 572 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 573 &F.getEntryBlock() != BB) 574 return false; 575 576 // Do not instrument full dominators, or full post-dominators with multiple 577 // predecessors. 578 return !isFullDominator(BB, DT) 579 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 580 } 581 582 583 // Returns true iff From->To is a backedge. 584 // A twist here is that we treat From->To as a backedge if 585 // * To dominates From or 586 // * To->UniqueSuccessor dominates From 587 static bool IsBackEdge(BasicBlock *From, BasicBlock *To, 588 const DominatorTree *DT) { 589 if (DT->dominates(To, From)) 590 return true; 591 if (auto Next = To->getUniqueSuccessor()) 592 if (DT->dominates(Next, From)) 593 return true; 594 return false; 595 } 596 597 // Prunes uninteresting Cmp instrumentation: 598 // * CMP instructions that feed into loop backedge branch. 599 // 600 // Note that Cmp pruning is controlled by the same flag as the 601 // BB pruning. 602 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, 603 const SanitizerCoverageOptions &Options) { 604 if (!Options.NoPrune) 605 if (CMP->hasOneUse()) 606 if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) 607 for (BasicBlock *B : BR->successors()) 608 if (IsBackEdge(BR->getParent(), B, DT)) 609 return false; 610 return true; 611 } 612 613 void ModuleSanitizerCoverage::instrumentFunction( 614 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) { 615 if (F.empty()) 616 return; 617 if (F.getName().find(".module_ctor") != std::string::npos) 618 return; // Should not instrument sanitizer init functions. 619 if (F.getName().startswith("__sanitizer_")) 620 return; // Don't instrument __sanitizer_* callbacks. 621 // Don't touch available_externally functions, their actual body is elewhere. 622 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 623 return; 624 // Don't instrument MSVC CRT configuration helpers. They may run before normal 625 // initialization. 626 if (F.getName() == "__local_stdio_printf_options" || 627 F.getName() == "__local_stdio_scanf_options") 628 return; 629 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) 630 return; 631 // Don't instrument functions using SEH for now. Splitting basic blocks like 632 // we do for coverage breaks WinEHPrepare. 633 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 634 if (F.hasPersonalityFn() && 635 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 636 return; 637 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName())) 638 return; 639 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName())) 640 return; 641 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage)) 642 return; 643 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 644 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); 645 SmallVector<Instruction *, 8> IndirCalls; 646 SmallVector<BasicBlock *, 16> BlocksToInstrument; 647 SmallVector<Instruction *, 8> CmpTraceTargets; 648 SmallVector<Instruction *, 8> SwitchTraceTargets; 649 SmallVector<BinaryOperator *, 8> DivTraceTargets; 650 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 651 SmallVector<LoadInst *, 8> Loads; 652 SmallVector<StoreInst *, 8> Stores; 653 654 const DominatorTree *DT = DTCallback(F); 655 const PostDominatorTree *PDT = PDTCallback(F); 656 bool IsLeafFunc = true; 657 658 for (auto &BB : F) { 659 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 660 BlocksToInstrument.push_back(&BB); 661 for (auto &Inst : BB) { 662 if (Options.IndirectCalls) { 663 CallBase *CB = dyn_cast<CallBase>(&Inst); 664 if (CB && CB->isIndirectCall()) 665 IndirCalls.push_back(&Inst); 666 } 667 if (Options.TraceCmp) { 668 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) 669 if (IsInterestingCmp(CMP, DT, Options)) 670 CmpTraceTargets.push_back(&Inst); 671 if (isa<SwitchInst>(&Inst)) 672 SwitchTraceTargets.push_back(&Inst); 673 } 674 if (Options.TraceDiv) 675 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 676 if (BO->getOpcode() == Instruction::SDiv || 677 BO->getOpcode() == Instruction::UDiv) 678 DivTraceTargets.push_back(BO); 679 if (Options.TraceGep) 680 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 681 GepTraceTargets.push_back(GEP); 682 if (Options.TraceLoads) 683 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst)) 684 Loads.push_back(LI); 685 if (Options.TraceStores) 686 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst)) 687 Stores.push_back(SI); 688 if (Options.StackDepth) 689 if (isa<InvokeInst>(Inst) || 690 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 691 IsLeafFunc = false; 692 } 693 } 694 695 if (Options.CollectControlFlow) 696 createFunctionControlFlow(F); 697 698 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 699 InjectCoverageForIndirectCalls(F, IndirCalls); 700 InjectTraceForCmp(F, CmpTraceTargets); 701 InjectTraceForSwitch(F, SwitchTraceTargets); 702 InjectTraceForDiv(F, DivTraceTargets); 703 InjectTraceForGep(F, GepTraceTargets); 704 InjectTraceForLoadsAndStores(F, Loads, Stores); 705 } 706 707 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection( 708 size_t NumElements, Function &F, Type *Ty, const char *Section) { 709 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 710 auto Array = new GlobalVariable( 711 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 712 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 713 714 if (TargetTriple.supportsCOMDAT() && 715 (TargetTriple.isOSBinFormatELF() || !F.isInterposable())) 716 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple)) 717 Array->setComdat(Comdat); 718 Array->setSection(getSectionName(Section)); 719 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue())); 720 721 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g. 722 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other 723 // section(s) as a unit, so we conservatively retain all unconditionally in 724 // the compiler. 725 // 726 // With comdat (COFF/ELF), the linker can guarantee the associated sections 727 // will be retained or discarded as a unit, so llvm.compiler.used is 728 // sufficient. Otherwise, conservatively make all of them retained by the 729 // linker. 730 if (Array->hasComdat()) 731 GlobalsToAppendToCompilerUsed.push_back(Array); 732 else 733 GlobalsToAppendToUsed.push_back(Array); 734 735 return Array; 736 } 737 738 GlobalVariable * 739 ModuleSanitizerCoverage::CreatePCArray(Function &F, 740 ArrayRef<BasicBlock *> AllBlocks) { 741 size_t N = AllBlocks.size(); 742 assert(N); 743 SmallVector<Constant *, 32> PCs; 744 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 745 for (size_t i = 0; i < N; i++) { 746 if (&F.getEntryBlock() == AllBlocks[i]) { 747 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 748 PCs.push_back((Constant *)IRB.CreateIntToPtr( 749 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 750 } else { 751 PCs.push_back((Constant *)IRB.CreatePointerCast( 752 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 753 PCs.push_back(Constant::getNullValue(IntptrPtrTy)); 754 } 755 } 756 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 757 SanCovPCsSectionName); 758 PCArray->setInitializer( 759 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 760 PCArray->setConstant(true); 761 762 return PCArray; 763 } 764 765 void ModuleSanitizerCoverage::CreateFunctionLocalArrays( 766 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 767 if (Options.TracePCGuard) 768 FunctionGuardArray = CreateFunctionLocalArrayInSection( 769 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 770 771 if (Options.Inline8bitCounters) 772 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 773 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 774 if (Options.InlineBoolFlag) 775 FunctionBoolArray = CreateFunctionLocalArrayInSection( 776 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName); 777 778 if (Options.PCTable) 779 FunctionPCsArray = CreatePCArray(F, AllBlocks); 780 } 781 782 bool ModuleSanitizerCoverage::InjectCoverage(Function &F, 783 ArrayRef<BasicBlock *> AllBlocks, 784 bool IsLeafFunc) { 785 if (AllBlocks.empty()) return false; 786 CreateFunctionLocalArrays(F, AllBlocks); 787 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 788 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 789 return true; 790 } 791 792 // On every indirect call we call a run-time function 793 // __sanitizer_cov_indir_call* with two parameters: 794 // - callee address, 795 // - global cache array that contains CacheSize pointers (zero-initialized). 796 // The cache is used to speed up recording the caller-callee pairs. 797 // The address of the caller is passed implicitly via caller PC. 798 // CacheSize is encoded in the name of the run-time function. 799 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls( 800 Function &F, ArrayRef<Instruction *> IndirCalls) { 801 if (IndirCalls.empty()) 802 return; 803 assert(Options.TracePC || Options.TracePCGuard || 804 Options.Inline8bitCounters || Options.InlineBoolFlag); 805 for (auto *I : IndirCalls) { 806 InstrumentationIRBuilder IRB(I); 807 CallBase &CB = cast<CallBase>(*I); 808 Value *Callee = CB.getCalledOperand(); 809 if (isa<InlineAsm>(Callee)) 810 continue; 811 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 812 } 813 } 814 815 // For every switch statement we insert a call: 816 // __sanitizer_cov_trace_switch(CondValue, 817 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 818 819 void ModuleSanitizerCoverage::InjectTraceForSwitch( 820 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 821 for (auto *I : SwitchTraceTargets) { 822 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 823 InstrumentationIRBuilder IRB(I); 824 SmallVector<Constant *, 16> Initializers; 825 Value *Cond = SI->getCondition(); 826 if (Cond->getType()->getScalarSizeInBits() > 827 Int64Ty->getScalarSizeInBits()) 828 continue; 829 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 830 Initializers.push_back( 831 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 832 if (Cond->getType()->getScalarSizeInBits() < 833 Int64Ty->getScalarSizeInBits()) 834 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 835 for (auto It : SI->cases()) { 836 Constant *C = It.getCaseValue(); 837 if (C->getType()->getScalarSizeInBits() < 838 Int64Ty->getScalarSizeInBits()) 839 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 840 Initializers.push_back(C); 841 } 842 llvm::sort(drop_begin(Initializers, 2), 843 [](const Constant *A, const Constant *B) { 844 return cast<ConstantInt>(A)->getLimitedValue() < 845 cast<ConstantInt>(B)->getLimitedValue(); 846 }); 847 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 848 GlobalVariable *GV = new GlobalVariable( 849 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 850 ConstantArray::get(ArrayOfInt64Ty, Initializers), 851 "__sancov_gen_cov_switch_values"); 852 IRB.CreateCall(SanCovTraceSwitchFunction, 853 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 854 } 855 } 856 } 857 858 void ModuleSanitizerCoverage::InjectTraceForDiv( 859 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 860 for (auto *BO : DivTraceTargets) { 861 InstrumentationIRBuilder IRB(BO); 862 Value *A1 = BO->getOperand(1); 863 if (isa<ConstantInt>(A1)) continue; 864 if (!A1->getType()->isIntegerTy()) 865 continue; 866 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 867 int CallbackIdx = TypeSize == 32 ? 0 : 868 TypeSize == 64 ? 1 : -1; 869 if (CallbackIdx < 0) continue; 870 auto Ty = Type::getIntNTy(*C, TypeSize); 871 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 872 {IRB.CreateIntCast(A1, Ty, true)}); 873 } 874 } 875 876 void ModuleSanitizerCoverage::InjectTraceForGep( 877 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 878 for (auto *GEP : GepTraceTargets) { 879 InstrumentationIRBuilder IRB(GEP); 880 for (Use &Idx : GEP->indices()) 881 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy()) 882 IRB.CreateCall(SanCovTraceGepFunction, 883 {IRB.CreateIntCast(Idx, IntptrTy, true)}); 884 } 885 } 886 887 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores( 888 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) { 889 auto CallbackIdx = [&](Type *ElementTy) -> int { 890 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy); 891 return TypeSize == 8 ? 0 892 : TypeSize == 16 ? 1 893 : TypeSize == 32 ? 2 894 : TypeSize == 64 ? 3 895 : TypeSize == 128 ? 4 896 : -1; 897 }; 898 Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy, 899 Int128PtrTy}; 900 for (auto *LI : Loads) { 901 InstrumentationIRBuilder IRB(LI); 902 auto Ptr = LI->getPointerOperand(); 903 int Idx = CallbackIdx(LI->getType()); 904 if (Idx < 0) 905 continue; 906 IRB.CreateCall(SanCovLoadFunction[Idx], 907 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 908 } 909 for (auto *SI : Stores) { 910 InstrumentationIRBuilder IRB(SI); 911 auto Ptr = SI->getPointerOperand(); 912 int Idx = CallbackIdx(SI->getValueOperand()->getType()); 913 if (Idx < 0) 914 continue; 915 IRB.CreateCall(SanCovStoreFunction[Idx], 916 IRB.CreatePointerCast(Ptr, PointerType[Idx])); 917 } 918 } 919 920 void ModuleSanitizerCoverage::InjectTraceForCmp( 921 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 922 for (auto *I : CmpTraceTargets) { 923 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 924 InstrumentationIRBuilder IRB(ICMP); 925 Value *A0 = ICMP->getOperand(0); 926 Value *A1 = ICMP->getOperand(1); 927 if (!A0->getType()->isIntegerTy()) 928 continue; 929 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 930 int CallbackIdx = TypeSize == 8 ? 0 : 931 TypeSize == 16 ? 1 : 932 TypeSize == 32 ? 2 : 933 TypeSize == 64 ? 3 : -1; 934 if (CallbackIdx < 0) continue; 935 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 936 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 937 bool FirstIsConst = isa<ConstantInt>(A0); 938 bool SecondIsConst = isa<ConstantInt>(A1); 939 // If both are const, then we don't need such a comparison. 940 if (FirstIsConst && SecondIsConst) continue; 941 // If only one is const, then make it the first callback argument. 942 if (FirstIsConst || SecondIsConst) { 943 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 944 if (SecondIsConst) 945 std::swap(A0, A1); 946 } 947 948 auto Ty = Type::getIntNTy(*C, TypeSize); 949 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 950 IRB.CreateIntCast(A1, Ty, true)}); 951 } 952 } 953 } 954 955 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 956 size_t Idx, 957 bool IsLeafFunc) { 958 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 959 bool IsEntryBB = &BB == &F.getEntryBlock(); 960 DebugLoc EntryLoc; 961 if (IsEntryBB) { 962 if (auto SP = F.getSubprogram()) 963 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP); 964 // Keep static allocas and llvm.localescape calls in the entry block. Even 965 // if we aren't splitting the block, it's nice for allocas to be before 966 // calls. 967 IP = PrepareToSplitEntryBlock(BB, IP); 968 } 969 970 InstrumentationIRBuilder IRB(&*IP); 971 if (EntryLoc) 972 IRB.SetCurrentDebugLocation(EntryLoc); 973 if (Options.TracePC) { 974 IRB.CreateCall(SanCovTracePC) 975 ->setCannotMerge(); // gets the PC using GET_CALLER_PC. 976 } 977 if (Options.TracePCGuard) { 978 auto GuardPtr = IRB.CreateIntToPtr( 979 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 980 ConstantInt::get(IntptrTy, Idx * 4)), 981 Int32PtrTy); 982 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge(); 983 } 984 if (Options.Inline8bitCounters) { 985 auto CounterPtr = IRB.CreateGEP( 986 Function8bitCounterArray->getValueType(), Function8bitCounterArray, 987 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 988 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); 989 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 990 auto Store = IRB.CreateStore(Inc, CounterPtr); 991 Load->setNoSanitizeMetadata(); 992 Store->setNoSanitizeMetadata(); 993 } 994 if (Options.InlineBoolFlag) { 995 auto FlagPtr = IRB.CreateGEP( 996 FunctionBoolArray->getValueType(), FunctionBoolArray, 997 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 998 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr); 999 auto ThenTerm = 1000 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false); 1001 IRBuilder<> ThenIRB(ThenTerm); 1002 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr); 1003 Load->setNoSanitizeMetadata(); 1004 Store->setNoSanitizeMetadata(); 1005 } 1006 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 1007 // Check stack depth. If it's the deepest so far, record it. 1008 Module *M = F.getParent(); 1009 Function *GetFrameAddr = Intrinsic::getDeclaration( 1010 M, Intrinsic::frameaddress, 1011 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace())); 1012 auto FrameAddrPtr = 1013 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 1014 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 1015 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); 1016 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 1017 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 1018 IRBuilder<> ThenIRB(ThenTerm); 1019 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 1020 LowestStack->setNoSanitizeMetadata(); 1021 Store->setNoSanitizeMetadata(); 1022 } 1023 } 1024 1025 std::string 1026 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const { 1027 if (TargetTriple.isOSBinFormatCOFF()) { 1028 if (Section == SanCovCountersSectionName) 1029 return ".SCOV$CM"; 1030 if (Section == SanCovBoolFlagSectionName) 1031 return ".SCOV$BM"; 1032 if (Section == SanCovPCsSectionName) 1033 return ".SCOVP$M"; 1034 return ".SCOV$GM"; // For SanCovGuardsSectionName. 1035 } 1036 if (TargetTriple.isOSBinFormatMachO()) 1037 return "__DATA,__" + Section; 1038 return "__" + Section; 1039 } 1040 1041 std::string 1042 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const { 1043 if (TargetTriple.isOSBinFormatMachO()) 1044 return "\1section$start$__DATA$__" + Section; 1045 return "__start___" + Section; 1046 } 1047 1048 std::string 1049 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const { 1050 if (TargetTriple.isOSBinFormatMachO()) 1051 return "\1section$end$__DATA$__" + Section; 1052 return "__stop___" + Section; 1053 } 1054 1055 void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) { 1056 SmallVector<Constant *, 32> CFs; 1057 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 1058 1059 for (auto &BB : F) { 1060 // blockaddress can not be used on function's entry block. 1061 if (&BB == &F.getEntryBlock()) 1062 CFs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 1063 else 1064 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(&BB), 1065 IntptrPtrTy)); 1066 1067 for (auto SuccBB : successors(&BB)) { 1068 assert(SuccBB != &F.getEntryBlock()); 1069 CFs.push_back((Constant *)IRB.CreatePointerCast(BlockAddress::get(SuccBB), 1070 IntptrPtrTy)); 1071 } 1072 1073 CFs.push_back((Constant *)Constant::getNullValue(IntptrPtrTy)); 1074 1075 for (auto &Inst : BB) { 1076 if (CallBase *CB = dyn_cast<CallBase>(&Inst)) { 1077 if (CB->isIndirectCall()) { 1078 // TODO(navidem): handle indirect calls, for now mark its existence. 1079 CFs.push_back((Constant *)IRB.CreateIntToPtr( 1080 ConstantInt::get(IntptrTy, -1), IntptrPtrTy)); 1081 } else { 1082 auto CalledF = CB->getCalledFunction(); 1083 if (CalledF && !CalledF->isIntrinsic()) 1084 CFs.push_back( 1085 (Constant *)IRB.CreatePointerCast(CalledF, IntptrPtrTy)); 1086 } 1087 } 1088 } 1089 1090 CFs.push_back((Constant *)Constant::getNullValue(IntptrPtrTy)); 1091 } 1092 1093 FunctionCFsArray = CreateFunctionLocalArrayInSection( 1094 CFs.size(), F, IntptrPtrTy, SanCovCFsSectionName); 1095 FunctionCFsArray->setInitializer( 1096 ConstantArray::get(ArrayType::get(IntptrPtrTy, CFs.size()), CFs)); 1097 FunctionCFsArray->setConstant(true); 1098 } 1099