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