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