1 //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // Coverage instrumentation done on LLVM IR level, works with Sanitizers. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ADT/ArrayRef.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/Analysis/EHPersonalities.h" 17 #include "llvm/Analysis/PostDominators.h" 18 #include "llvm/IR/CFG.h" 19 #include "llvm/IR/CallSite.h" 20 #include "llvm/IR/Constant.h" 21 #include "llvm/IR/DataLayout.h" 22 #include "llvm/IR/DebugInfo.h" 23 #include "llvm/IR/Dominators.h" 24 #include "llvm/IR/Function.h" 25 #include "llvm/IR/GlobalVariable.h" 26 #include "llvm/IR/IRBuilder.h" 27 #include "llvm/IR/InlineAsm.h" 28 #include "llvm/IR/IntrinsicInst.h" 29 #include "llvm/IR/Intrinsics.h" 30 #include "llvm/IR/LLVMContext.h" 31 #include "llvm/IR/MDBuilder.h" 32 #include "llvm/IR/Module.h" 33 #include "llvm/IR/Type.h" 34 #include "llvm/Support/CommandLine.h" 35 #include "llvm/Support/Debug.h" 36 #include "llvm/Support/raw_ostream.h" 37 #include "llvm/Transforms/Instrumentation.h" 38 #include "llvm/Transforms/Scalar.h" 39 #include "llvm/Transforms/Utils/BasicBlockUtils.h" 40 #include "llvm/Transforms/Utils/ModuleUtils.h" 41 42 using namespace llvm; 43 44 #define DEBUG_TYPE "sancov" 45 46 static const char *const SanCovTracePCIndirName = 47 "__sanitizer_cov_trace_pc_indir"; 48 static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc"; 49 static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1"; 50 static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2"; 51 static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4"; 52 static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8"; 53 static const char *const SanCovTraceConstCmp1 = 54 "__sanitizer_cov_trace_const_cmp1"; 55 static const char *const SanCovTraceConstCmp2 = 56 "__sanitizer_cov_trace_const_cmp2"; 57 static const char *const SanCovTraceConstCmp4 = 58 "__sanitizer_cov_trace_const_cmp4"; 59 static const char *const SanCovTraceConstCmp8 = 60 "__sanitizer_cov_trace_const_cmp8"; 61 static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4"; 62 static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8"; 63 static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep"; 64 static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch"; 65 static const char *const SanCovModuleCtorName = "sancov.module_ctor"; 66 static const uint64_t SanCtorAndDtorPriority = 2; 67 68 static const char *const SanCovTracePCGuardName = 69 "__sanitizer_cov_trace_pc_guard"; 70 static const char *const SanCovTracePCGuardInitName = 71 "__sanitizer_cov_trace_pc_guard_init"; 72 static const char *const SanCov8bitCountersInitName = 73 "__sanitizer_cov_8bit_counters_init"; 74 static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init"; 75 76 static const char *const SanCovGuardsSectionName = "sancov_guards"; 77 static const char *const SanCovCountersSectionName = "sancov_cntrs"; 78 static const char *const SanCovPCsSectionName = "sancov_pcs"; 79 80 static const char *const SanCovLowestStackName = "__sancov_lowest_stack"; 81 82 static cl::opt<int> ClCoverageLevel( 83 "sanitizer-coverage-level", 84 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " 85 "3: all blocks and critical edges"), 86 cl::Hidden, cl::init(0)); 87 88 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", 89 cl::desc("Experimental pc tracing"), cl::Hidden, 90 cl::init(false)); 91 92 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", 93 cl::desc("pc tracing with a guard"), 94 cl::Hidden, cl::init(false)); 95 96 // If true, we create a global variable that contains PCs of all instrumented 97 // BBs, put this global into a named section, and pass this section's bounds 98 // to __sanitizer_cov_pcs_init. 99 // This way the coverage instrumentation does not need to acquire the PCs 100 // at run-time. Works with trace-pc-guard and inline-8bit-counters. 101 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", 102 cl::desc("create a static PC table"), 103 cl::Hidden, cl::init(false)); 104 105 static cl::opt<bool> 106 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", 107 cl::desc("increments 8-bit counter for every edge"), 108 cl::Hidden, cl::init(false)); 109 110 static cl::opt<bool> 111 ClCMPTracing("sanitizer-coverage-trace-compares", 112 cl::desc("Tracing of CMP and similar instructions"), 113 cl::Hidden, cl::init(false)); 114 115 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", 116 cl::desc("Tracing of DIV instructions"), 117 cl::Hidden, cl::init(false)); 118 119 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", 120 cl::desc("Tracing of GEP instructions"), 121 cl::Hidden, cl::init(false)); 122 123 static cl::opt<bool> 124 ClPruneBlocks("sanitizer-coverage-prune-blocks", 125 cl::desc("Reduce the number of instrumented blocks"), 126 cl::Hidden, cl::init(true)); 127 128 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", 129 cl::desc("max stack depth tracing"), 130 cl::Hidden, cl::init(false)); 131 132 namespace { 133 134 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { 135 SanitizerCoverageOptions Res; 136 switch (LegacyCoverageLevel) { 137 case 0: 138 Res.CoverageType = SanitizerCoverageOptions::SCK_None; 139 break; 140 case 1: 141 Res.CoverageType = SanitizerCoverageOptions::SCK_Function; 142 break; 143 case 2: 144 Res.CoverageType = SanitizerCoverageOptions::SCK_BB; 145 break; 146 case 3: 147 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 148 break; 149 case 4: 150 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; 151 Res.IndirectCalls = true; 152 break; 153 } 154 return Res; 155 } 156 157 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { 158 // Sets CoverageType and IndirectCalls. 159 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); 160 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); 161 Options.IndirectCalls |= CLOpts.IndirectCalls; 162 Options.TraceCmp |= ClCMPTracing; 163 Options.TraceDiv |= ClDIVTracing; 164 Options.TraceGep |= ClGEPTracing; 165 Options.TracePC |= ClTracePC; 166 Options.TracePCGuard |= ClTracePCGuard; 167 Options.Inline8bitCounters |= ClInline8bitCounters; 168 Options.PCTable |= ClCreatePCTable; 169 Options.NoPrune |= !ClPruneBlocks; 170 Options.StackDepth |= ClStackDepth; 171 if (!Options.TracePCGuard && !Options.TracePC && 172 !Options.Inline8bitCounters && !Options.StackDepth) 173 Options.TracePCGuard = true; // TracePCGuard is default. 174 return Options; 175 } 176 177 class SanitizerCoverageModule : public ModulePass { 178 public: 179 SanitizerCoverageModule( 180 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions()) 181 : ModulePass(ID), Options(OverrideFromCL(Options)) { 182 initializeSanitizerCoverageModulePass(*PassRegistry::getPassRegistry()); 183 } 184 bool runOnModule(Module &M) override; 185 bool runOnFunction(Function &F); 186 static char ID; // Pass identification, replacement for typeid 187 StringRef getPassName() const override { return "SanitizerCoverageModule"; } 188 189 void getAnalysisUsage(AnalysisUsage &AU) const override { 190 AU.addRequired<DominatorTreeWrapperPass>(); 191 AU.addRequired<PostDominatorTreeWrapperPass>(); 192 } 193 194 private: 195 void InjectCoverageForIndirectCalls(Function &F, 196 ArrayRef<Instruction *> IndirCalls); 197 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); 198 void InjectTraceForDiv(Function &F, 199 ArrayRef<BinaryOperator *> DivTraceTargets); 200 void InjectTraceForGep(Function &F, 201 ArrayRef<GetElementPtrInst *> GepTraceTargets); 202 void InjectTraceForSwitch(Function &F, 203 ArrayRef<Instruction *> SwitchTraceTargets); 204 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, 205 bool IsLeafFunc = true); 206 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, 207 Function &F, Type *Ty, 208 const char *Section); 209 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); 210 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); 211 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, 212 bool IsLeafFunc = true); 213 Function *CreateInitCallsForSections(Module &M, const char *InitFunctionName, 214 Type *Ty, const char *Section); 215 std::pair<GlobalVariable *, GlobalVariable *> 216 CreateSecStartEnd(Module &M, const char *Section, Type *Ty); 217 218 void SetNoSanitizeMetadata(Instruction *I) { 219 I->setMetadata(I->getModule()->getMDKindID("nosanitize"), 220 MDNode::get(*C, None)); 221 } 222 223 std::string getSectionName(const std::string &Section) const; 224 std::string getSectionStart(const std::string &Section) const; 225 std::string getSectionEnd(const std::string &Section) const; 226 Function *SanCovTracePCIndir; 227 Function *SanCovTracePC, *SanCovTracePCGuard; 228 Function *SanCovTraceCmpFunction[4]; 229 Function *SanCovTraceConstCmpFunction[4]; 230 Function *SanCovTraceDivFunction[2]; 231 Function *SanCovTraceGepFunction; 232 Function *SanCovTraceSwitchFunction; 233 GlobalVariable *SanCovLowestStack; 234 InlineAsm *EmptyAsm; 235 Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy, 236 *Int16Ty, *Int8Ty, *Int8PtrTy; 237 Module *CurModule; 238 Triple TargetTriple; 239 LLVMContext *C; 240 const DataLayout *DL; 241 242 GlobalVariable *FunctionGuardArray; // for trace-pc-guard. 243 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. 244 GlobalVariable *FunctionPCsArray; // for pc-table. 245 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; 246 247 SanitizerCoverageOptions Options; 248 }; 249 250 } // namespace 251 252 std::pair<GlobalVariable *, GlobalVariable *> 253 SanitizerCoverageModule::CreateSecStartEnd(Module &M, const char *Section, 254 Type *Ty) { 255 GlobalVariable *SecStart = 256 new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr, 257 getSectionStart(Section)); 258 SecStart->setVisibility(GlobalValue::HiddenVisibility); 259 GlobalVariable *SecEnd = 260 new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, 261 nullptr, getSectionEnd(Section)); 262 SecEnd->setVisibility(GlobalValue::HiddenVisibility); 263 264 return std::make_pair(SecStart, SecEnd); 265 } 266 267 268 Function *SanitizerCoverageModule::CreateInitCallsForSections( 269 Module &M, const char *InitFunctionName, Type *Ty, 270 const char *Section) { 271 IRBuilder<> IRB(M.getContext()); 272 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); 273 auto SecStart = SecStartEnd.first; 274 auto SecEnd = SecStartEnd.second; 275 Function *CtorFunc; 276 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( 277 M, SanCovModuleCtorName, InitFunctionName, {Ty, Ty}, 278 {IRB.CreatePointerCast(SecStart, Ty), IRB.CreatePointerCast(SecEnd, Ty)}); 279 280 if (TargetTriple.supportsCOMDAT()) { 281 // Use comdat to dedup CtorFunc. 282 CtorFunc->setComdat(M.getOrInsertComdat(SanCovModuleCtorName)); 283 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); 284 } else { 285 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); 286 } 287 return CtorFunc; 288 } 289 290 bool SanitizerCoverageModule::runOnModule(Module &M) { 291 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) 292 return false; 293 C = &(M.getContext()); 294 DL = &M.getDataLayout(); 295 CurModule = &M; 296 TargetTriple = Triple(M.getTargetTriple()); 297 FunctionGuardArray = nullptr; 298 Function8bitCounterArray = nullptr; 299 FunctionPCsArray = nullptr; 300 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); 301 IntptrPtrTy = PointerType::getUnqual(IntptrTy); 302 Type *VoidTy = Type::getVoidTy(*C); 303 IRBuilder<> IRB(*C); 304 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); 305 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); 306 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); 307 Int64Ty = IRB.getInt64Ty(); 308 Int32Ty = IRB.getInt32Ty(); 309 Int16Ty = IRB.getInt16Ty(); 310 Int8Ty = IRB.getInt8Ty(); 311 312 SanCovTracePCIndir = checkSanitizerInterfaceFunction( 313 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy)); 314 SanCovTraceCmpFunction[0] = 315 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 316 SanCovTraceCmp1, VoidTy, IRB.getInt8Ty(), IRB.getInt8Ty())); 317 SanCovTraceCmpFunction[1] = checkSanitizerInterfaceFunction( 318 M.getOrInsertFunction(SanCovTraceCmp2, VoidTy, IRB.getInt16Ty(), 319 IRB.getInt16Ty())); 320 SanCovTraceCmpFunction[2] = checkSanitizerInterfaceFunction( 321 M.getOrInsertFunction(SanCovTraceCmp4, VoidTy, IRB.getInt32Ty(), 322 IRB.getInt32Ty())); 323 SanCovTraceCmpFunction[3] = 324 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 325 SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty)); 326 327 SanCovTraceConstCmpFunction[0] = 328 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 329 SanCovTraceConstCmp1, VoidTy, Int8Ty, Int8Ty)); 330 SanCovTraceConstCmpFunction[1] = 331 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 332 SanCovTraceConstCmp2, VoidTy, Int16Ty, Int16Ty)); 333 SanCovTraceConstCmpFunction[2] = 334 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 335 SanCovTraceConstCmp4, VoidTy, Int32Ty, Int32Ty)); 336 SanCovTraceConstCmpFunction[3] = 337 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 338 SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty)); 339 340 SanCovTraceDivFunction[0] = 341 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 342 SanCovTraceDiv4, VoidTy, IRB.getInt32Ty())); 343 SanCovTraceDivFunction[1] = 344 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 345 SanCovTraceDiv8, VoidTy, Int64Ty)); 346 SanCovTraceGepFunction = 347 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 348 SanCovTraceGep, VoidTy, IntptrTy)); 349 SanCovTraceSwitchFunction = 350 checkSanitizerInterfaceFunction(M.getOrInsertFunction( 351 SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy)); 352 353 Constant *SanCovLowestStackConstant = 354 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); 355 SanCovLowestStack = cast<GlobalVariable>(SanCovLowestStackConstant); 356 SanCovLowestStack->setThreadLocalMode( 357 GlobalValue::ThreadLocalMode::InitialExecTLSModel); 358 if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) 359 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); 360 361 // Make sure smaller parameters are zero-extended to i64 as required by the 362 // x86_64 ABI. 363 if (TargetTriple.getArch() == Triple::x86_64) { 364 for (int i = 0; i < 3; i++) { 365 SanCovTraceCmpFunction[i]->addParamAttr(0, Attribute::ZExt); 366 SanCovTraceCmpFunction[i]->addParamAttr(1, Attribute::ZExt); 367 SanCovTraceConstCmpFunction[i]->addParamAttr(0, Attribute::ZExt); 368 SanCovTraceConstCmpFunction[i]->addParamAttr(1, Attribute::ZExt); 369 } 370 SanCovTraceDivFunction[0]->addParamAttr(0, Attribute::ZExt); 371 } 372 373 374 // We insert an empty inline asm after cov callbacks to avoid callback merge. 375 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false), 376 StringRef(""), StringRef(""), 377 /*hasSideEffects=*/true); 378 379 SanCovTracePC = checkSanitizerInterfaceFunction( 380 M.getOrInsertFunction(SanCovTracePCName, VoidTy)); 381 SanCovTracePCGuard = checkSanitizerInterfaceFunction(M.getOrInsertFunction( 382 SanCovTracePCGuardName, VoidTy, Int32PtrTy)); 383 384 for (auto &F : M) 385 runOnFunction(F); 386 387 Function *Ctor = nullptr; 388 389 if (FunctionGuardArray) 390 Ctor = CreateInitCallsForSections(M, SanCovTracePCGuardInitName, Int32PtrTy, 391 SanCovGuardsSectionName); 392 if (Function8bitCounterArray) 393 Ctor = CreateInitCallsForSections(M, SanCov8bitCountersInitName, Int8PtrTy, 394 SanCovCountersSectionName); 395 if (Ctor && Options.PCTable) { 396 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy); 397 Function *InitFunction = declareSanitizerInitFunction( 398 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); 399 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); 400 IRBCtor.CreateCall(InitFunction, 401 {IRB.CreatePointerCast(SecStartEnd.first, IntptrPtrTy), 402 IRB.CreatePointerCast(SecStartEnd.second, IntptrPtrTy)}); 403 } 404 // We don't reference these arrays directly in any of our runtime functions, 405 // so we need to prevent them from being dead stripped. 406 if (TargetTriple.isOSBinFormatMachO()) 407 appendToUsed(M, GlobalsToAppendToUsed); 408 return true; 409 } 410 411 // True if block has successors and it dominates all of them. 412 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { 413 if (succ_begin(BB) == succ_end(BB)) 414 return false; 415 416 for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) { 417 if (!DT->dominates(BB, SUCC)) 418 return false; 419 } 420 421 return true; 422 } 423 424 // True if block has predecessors and it postdominates all of them. 425 static bool isFullPostDominator(const BasicBlock *BB, 426 const PostDominatorTree *PDT) { 427 if (pred_begin(BB) == pred_end(BB)) 428 return false; 429 430 for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) { 431 if (!PDT->dominates(BB, PRED)) 432 return false; 433 } 434 435 return true; 436 } 437 438 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB, 439 const DominatorTree *DT, 440 const PostDominatorTree *PDT, 441 const SanitizerCoverageOptions &Options) { 442 // Don't insert coverage for unreachable blocks: we will never call 443 // __sanitizer_cov() for them, so counting them in 444 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage 445 // percentage. Also, unreachable instructions frequently have no debug 446 // locations. 447 if (isa<UnreachableInst>(BB->getTerminator())) 448 return false; 449 450 // Don't insert coverage into blocks without a valid insertion point 451 // (catchswitch blocks). 452 if (BB->getFirstInsertionPt() == BB->end()) 453 return false; 454 455 if (Options.NoPrune || &F.getEntryBlock() == BB) 456 return true; 457 458 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && 459 &F.getEntryBlock() != BB) 460 return false; 461 462 // Do not instrument full dominators, or full post-dominators with multiple 463 // predecessors. 464 return !isFullDominator(BB, DT) 465 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); 466 } 467 468 bool SanitizerCoverageModule::runOnFunction(Function &F) { 469 if (F.empty()) 470 return false; 471 if (F.getName().find(".module_ctor") != std::string::npos) 472 return false; // Should not instrument sanitizer init functions. 473 if (F.getName().startswith("__sanitizer_")) 474 return false; // Don't instrument __sanitizer_* callbacks. 475 // Don't touch available_externally functions, their actual body is elewhere. 476 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) 477 return false; 478 // Don't instrument MSVC CRT configuration helpers. They may run before normal 479 // initialization. 480 if (F.getName() == "__local_stdio_printf_options" || 481 F.getName() == "__local_stdio_scanf_options") 482 return false; 483 // Don't instrument functions using SEH for now. Splitting basic blocks like 484 // we do for coverage breaks WinEHPrepare. 485 // FIXME: Remove this when SEH no longer uses landingpad pattern matching. 486 if (F.hasPersonalityFn() && 487 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) 488 return false; 489 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) 490 SplitAllCriticalEdges(F); 491 SmallVector<Instruction *, 8> IndirCalls; 492 SmallVector<BasicBlock *, 16> BlocksToInstrument; 493 SmallVector<Instruction *, 8> CmpTraceTargets; 494 SmallVector<Instruction *, 8> SwitchTraceTargets; 495 SmallVector<BinaryOperator *, 8> DivTraceTargets; 496 SmallVector<GetElementPtrInst *, 8> GepTraceTargets; 497 498 const DominatorTree *DT = 499 &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); 500 const PostDominatorTree *PDT = 501 &getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree(); 502 bool IsLeafFunc = true; 503 504 for (auto &BB : F) { 505 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) 506 BlocksToInstrument.push_back(&BB); 507 for (auto &Inst : BB) { 508 if (Options.IndirectCalls) { 509 CallSite CS(&Inst); 510 if (CS && !CS.getCalledFunction()) 511 IndirCalls.push_back(&Inst); 512 } 513 if (Options.TraceCmp) { 514 if (isa<ICmpInst>(&Inst)) 515 CmpTraceTargets.push_back(&Inst); 516 if (isa<SwitchInst>(&Inst)) 517 SwitchTraceTargets.push_back(&Inst); 518 } 519 if (Options.TraceDiv) 520 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) 521 if (BO->getOpcode() == Instruction::SDiv || 522 BO->getOpcode() == Instruction::UDiv) 523 DivTraceTargets.push_back(BO); 524 if (Options.TraceGep) 525 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) 526 GepTraceTargets.push_back(GEP); 527 if (Options.StackDepth) 528 if (isa<InvokeInst>(Inst) || 529 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) 530 IsLeafFunc = false; 531 } 532 } 533 534 InjectCoverage(F, BlocksToInstrument, IsLeafFunc); 535 InjectCoverageForIndirectCalls(F, IndirCalls); 536 InjectTraceForCmp(F, CmpTraceTargets); 537 InjectTraceForSwitch(F, SwitchTraceTargets); 538 InjectTraceForDiv(F, DivTraceTargets); 539 InjectTraceForGep(F, GepTraceTargets); 540 return true; 541 } 542 543 GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection( 544 size_t NumElements, Function &F, Type *Ty, const char *Section) { 545 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); 546 auto Array = new GlobalVariable( 547 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, 548 Constant::getNullValue(ArrayTy), "__sancov_gen_"); 549 if (auto Comdat = F.getComdat()) 550 Array->setComdat(Comdat); 551 Array->setSection(getSectionName(Section)); 552 Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize() 553 : Ty->getPrimitiveSizeInBits() / 8); 554 return Array; 555 } 556 557 GlobalVariable * 558 SanitizerCoverageModule::CreatePCArray(Function &F, 559 ArrayRef<BasicBlock *> AllBlocks) { 560 size_t N = AllBlocks.size(); 561 assert(N); 562 SmallVector<Constant *, 32> PCs; 563 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); 564 for (size_t i = 0; i < N; i++) { 565 if (&F.getEntryBlock() == AllBlocks[i]) { 566 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); 567 PCs.push_back((Constant *)IRB.CreateIntToPtr( 568 ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); 569 } else { 570 PCs.push_back((Constant *)IRB.CreatePointerCast( 571 BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); 572 PCs.push_back((Constant *)IRB.CreateIntToPtr( 573 ConstantInt::get(IntptrTy, 0), IntptrPtrTy)); 574 } 575 } 576 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, 577 SanCovPCsSectionName); 578 PCArray->setInitializer( 579 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); 580 PCArray->setConstant(true); 581 582 return PCArray; 583 } 584 585 void SanitizerCoverageModule::CreateFunctionLocalArrays( 586 Function &F, ArrayRef<BasicBlock *> AllBlocks) { 587 if (Options.TracePCGuard) { 588 FunctionGuardArray = CreateFunctionLocalArrayInSection( 589 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); 590 GlobalsToAppendToUsed.push_back(FunctionGuardArray); 591 } 592 if (Options.Inline8bitCounters) { 593 Function8bitCounterArray = CreateFunctionLocalArrayInSection( 594 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); 595 GlobalsToAppendToUsed.push_back(Function8bitCounterArray); 596 } 597 if (Options.PCTable) { 598 FunctionPCsArray = CreatePCArray(F, AllBlocks); 599 GlobalsToAppendToUsed.push_back(FunctionPCsArray); 600 } 601 } 602 603 bool SanitizerCoverageModule::InjectCoverage(Function &F, 604 ArrayRef<BasicBlock *> AllBlocks, 605 bool IsLeafFunc) { 606 if (AllBlocks.empty()) return false; 607 CreateFunctionLocalArrays(F, AllBlocks); 608 for (size_t i = 0, N = AllBlocks.size(); i < N; i++) 609 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); 610 return true; 611 } 612 613 // On every indirect call we call a run-time function 614 // __sanitizer_cov_indir_call* with two parameters: 615 // - callee address, 616 // - global cache array that contains CacheSize pointers (zero-initialized). 617 // The cache is used to speed up recording the caller-callee pairs. 618 // The address of the caller is passed implicitly via caller PC. 619 // CacheSize is encoded in the name of the run-time function. 620 void SanitizerCoverageModule::InjectCoverageForIndirectCalls( 621 Function &F, ArrayRef<Instruction *> IndirCalls) { 622 if (IndirCalls.empty()) 623 return; 624 assert(Options.TracePC || Options.TracePCGuard || Options.Inline8bitCounters); 625 for (auto I : IndirCalls) { 626 IRBuilder<> IRB(I); 627 CallSite CS(I); 628 Value *Callee = CS.getCalledValue(); 629 if (isa<InlineAsm>(Callee)) 630 continue; 631 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy)); 632 } 633 } 634 635 // For every switch statement we insert a call: 636 // __sanitizer_cov_trace_switch(CondValue, 637 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) 638 639 void SanitizerCoverageModule::InjectTraceForSwitch( 640 Function &, ArrayRef<Instruction *> SwitchTraceTargets) { 641 for (auto I : SwitchTraceTargets) { 642 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { 643 IRBuilder<> IRB(I); 644 SmallVector<Constant *, 16> Initializers; 645 Value *Cond = SI->getCondition(); 646 if (Cond->getType()->getScalarSizeInBits() > 647 Int64Ty->getScalarSizeInBits()) 648 continue; 649 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); 650 Initializers.push_back( 651 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); 652 if (Cond->getType()->getScalarSizeInBits() < 653 Int64Ty->getScalarSizeInBits()) 654 Cond = IRB.CreateIntCast(Cond, Int64Ty, false); 655 for (auto It : SI->cases()) { 656 Constant *C = It.getCaseValue(); 657 if (C->getType()->getScalarSizeInBits() < 658 Int64Ty->getScalarSizeInBits()) 659 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); 660 Initializers.push_back(C); 661 } 662 std::sort(Initializers.begin() + 2, Initializers.end(), 663 [](const Constant *A, const Constant *B) { 664 return cast<ConstantInt>(A)->getLimitedValue() < 665 cast<ConstantInt>(B)->getLimitedValue(); 666 }); 667 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); 668 GlobalVariable *GV = new GlobalVariable( 669 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, 670 ConstantArray::get(ArrayOfInt64Ty, Initializers), 671 "__sancov_gen_cov_switch_values"); 672 IRB.CreateCall(SanCovTraceSwitchFunction, 673 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); 674 } 675 } 676 } 677 678 void SanitizerCoverageModule::InjectTraceForDiv( 679 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { 680 for (auto BO : DivTraceTargets) { 681 IRBuilder<> IRB(BO); 682 Value *A1 = BO->getOperand(1); 683 if (isa<ConstantInt>(A1)) continue; 684 if (!A1->getType()->isIntegerTy()) 685 continue; 686 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); 687 int CallbackIdx = TypeSize == 32 ? 0 : 688 TypeSize == 64 ? 1 : -1; 689 if (CallbackIdx < 0) continue; 690 auto Ty = Type::getIntNTy(*C, TypeSize); 691 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], 692 {IRB.CreateIntCast(A1, Ty, true)}); 693 } 694 } 695 696 void SanitizerCoverageModule::InjectTraceForGep( 697 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { 698 for (auto GEP : GepTraceTargets) { 699 IRBuilder<> IRB(GEP); 700 for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I) 701 if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy()) 702 IRB.CreateCall(SanCovTraceGepFunction, 703 {IRB.CreateIntCast(*I, IntptrTy, true)}); 704 } 705 } 706 707 void SanitizerCoverageModule::InjectTraceForCmp( 708 Function &, ArrayRef<Instruction *> CmpTraceTargets) { 709 for (auto I : CmpTraceTargets) { 710 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { 711 IRBuilder<> IRB(ICMP); 712 Value *A0 = ICMP->getOperand(0); 713 Value *A1 = ICMP->getOperand(1); 714 if (!A0->getType()->isIntegerTy()) 715 continue; 716 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); 717 int CallbackIdx = TypeSize == 8 ? 0 : 718 TypeSize == 16 ? 1 : 719 TypeSize == 32 ? 2 : 720 TypeSize == 64 ? 3 : -1; 721 if (CallbackIdx < 0) continue; 722 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); 723 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; 724 bool FirstIsConst = isa<ConstantInt>(A0); 725 bool SecondIsConst = isa<ConstantInt>(A1); 726 // If both are const, then we don't need such a comparison. 727 if (FirstIsConst && SecondIsConst) continue; 728 // If only one is const, then make it the first callback argument. 729 if (FirstIsConst || SecondIsConst) { 730 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; 731 if (SecondIsConst) 732 std::swap(A0, A1); 733 } 734 735 auto Ty = Type::getIntNTy(*C, TypeSize); 736 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), 737 IRB.CreateIntCast(A1, Ty, true)}); 738 } 739 } 740 } 741 742 void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB, 743 size_t Idx, 744 bool IsLeafFunc) { 745 BasicBlock::iterator IP = BB.getFirstInsertionPt(); 746 bool IsEntryBB = &BB == &F.getEntryBlock(); 747 DebugLoc EntryLoc; 748 if (IsEntryBB) { 749 if (auto SP = F.getSubprogram()) 750 EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP); 751 // Keep static allocas and llvm.localescape calls in the entry block. Even 752 // if we aren't splitting the block, it's nice for allocas to be before 753 // calls. 754 IP = PrepareToSplitEntryBlock(BB, IP); 755 } else { 756 EntryLoc = IP->getDebugLoc(); 757 } 758 759 IRBuilder<> IRB(&*IP); 760 IRB.SetCurrentDebugLocation(EntryLoc); 761 if (Options.TracePC) { 762 IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC. 763 IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. 764 } 765 if (Options.TracePCGuard) { 766 auto GuardPtr = IRB.CreateIntToPtr( 767 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), 768 ConstantInt::get(IntptrTy, Idx * 4)), 769 Int32PtrTy); 770 IRB.CreateCall(SanCovTracePCGuard, GuardPtr); 771 IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. 772 } 773 if (Options.Inline8bitCounters) { 774 auto CounterPtr = IRB.CreateGEP( 775 Function8bitCounterArray, 776 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); 777 auto Load = IRB.CreateLoad(CounterPtr); 778 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); 779 auto Store = IRB.CreateStore(Inc, CounterPtr); 780 SetNoSanitizeMetadata(Load); 781 SetNoSanitizeMetadata(Store); 782 } 783 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { 784 // Check stack depth. If it's the deepest so far, record it. 785 Function *GetFrameAddr = 786 Intrinsic::getDeclaration(F.getParent(), Intrinsic::frameaddress); 787 auto FrameAddrPtr = 788 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); 789 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); 790 auto LowestStack = IRB.CreateLoad(SanCovLowestStack); 791 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); 792 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); 793 IRBuilder<> ThenIRB(ThenTerm); 794 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); 795 SetNoSanitizeMetadata(LowestStack); 796 SetNoSanitizeMetadata(Store); 797 } 798 } 799 800 std::string 801 SanitizerCoverageModule::getSectionName(const std::string &Section) const { 802 if (TargetTriple.getObjectFormat() == Triple::COFF) 803 return ".SCOV$M"; 804 if (TargetTriple.isOSBinFormatMachO()) 805 return "__DATA,__" + Section; 806 return "__" + Section; 807 } 808 809 std::string 810 SanitizerCoverageModule::getSectionStart(const std::string &Section) const { 811 if (TargetTriple.isOSBinFormatMachO()) 812 return "\1section$start$__DATA$__" + Section; 813 return "__start___" + Section; 814 } 815 816 std::string 817 SanitizerCoverageModule::getSectionEnd(const std::string &Section) const { 818 if (TargetTriple.isOSBinFormatMachO()) 819 return "\1section$end$__DATA$__" + Section; 820 return "__stop___" + Section; 821 } 822 823 824 char SanitizerCoverageModule::ID = 0; 825 INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov", 826 "SanitizerCoverage: TODO." 827 "ModulePass", 828 false, false) 829 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) 830 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass) 831 INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov", 832 "SanitizerCoverage: TODO." 833 "ModulePass", 834 false, false) 835 ModulePass *llvm::createSanitizerCoverageModulePass( 836 const SanitizerCoverageOptions &Options) { 837 return new SanitizerCoverageModule(Options); 838 } 839