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