| //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Coverage instrumentation that works with AddressSanitizer |
| // and potentially with other Sanitizers. |
| // |
| // We create a Guard variable with the same linkage |
| // as the function and inject this code into the entry block (SCK_Function) |
| // or all blocks (SCK_BB): |
| // if (Guard < 0) { |
| // __sanitizer_cov(&Guard); |
| // } |
| // The accesses to Guard are atomic. The rest of the logic is |
| // in __sanitizer_cov (it's fine to call it more than once). |
| // |
| // With SCK_Edge we also split critical edges this effectively |
| // instrumenting all edges. |
| // |
| // This coverage implementation provides very limited data: |
| // it only tells if a given function (block) was ever executed. No counters. |
| // But for many use cases this is what we need and the added slowdown small. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/Analysis/EHPersonalities.h" |
| #include "llvm/Analysis/PostDominators.h" |
| #include "llvm/IR/CFG.h" |
| #include "llvm/IR/CallSite.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DebugInfo.h" |
| #include "llvm/IR/Dominators.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/IRBuilder.h" |
| #include "llvm/IR/InlineAsm.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/MDBuilder.h" |
| #include "llvm/IR/Module.h" |
| #include "llvm/IR/Type.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Instrumentation.h" |
| #include "llvm/Transforms/Scalar.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "sancov" |
| |
| static const char *const SanCovModuleInitName = "__sanitizer_cov_module_init"; |
| static const char *const SanCovName = "__sanitizer_cov"; |
| static const char *const SanCovWithCheckName = "__sanitizer_cov_with_check"; |
| static const char *const SanCovIndirCallName = "__sanitizer_cov_indir_call16"; |
| static const char *const SanCovTracePCIndirName = |
| "__sanitizer_cov_trace_pc_indir"; |
| static const char *const SanCovTraceEnterName = |
| "__sanitizer_cov_trace_func_enter"; |
| static const char *const SanCovTraceBBName = |
| "__sanitizer_cov_trace_basic_block"; |
| static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc"; |
| static const char *const SanCovTraceCmpName = "__sanitizer_cov_trace_cmp"; |
| static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch"; |
| static const char *const SanCovModuleCtorName = "sancov.module_ctor"; |
| static const uint64_t SanCtorAndDtorPriority = 2; |
| |
| static cl::opt<int> ClCoverageLevel( |
| "sanitizer-coverage-level", |
| cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, " |
| "3: all blocks and critical edges, " |
| "4: above plus indirect calls"), |
| cl::Hidden, cl::init(0)); |
| |
| static cl::opt<unsigned> ClCoverageBlockThreshold( |
| "sanitizer-coverage-block-threshold", |
| cl::desc("Use a callback with a guard check inside it if there are" |
| " more than this number of blocks."), |
| cl::Hidden, cl::init(500)); |
| |
| static cl::opt<bool> |
| ClExperimentalTracing("sanitizer-coverage-experimental-tracing", |
| cl::desc("Experimental basic-block tracing: insert " |
| "callbacks at every basic block"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> ClExperimentalTracePC("sanitizer-coverage-trace-pc", |
| cl::desc("Experimental pc tracing"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> |
| ClExperimentalCMPTracing("sanitizer-coverage-experimental-trace-compares", |
| cl::desc("Experimental tracing of CMP and similar " |
| "instructions"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> |
| ClPruneBlocks("sanitizer-coverage-prune-blocks", |
| cl::desc("Reduce the number of instrumented blocks"), |
| cl::Hidden, cl::init(true)); |
| |
| // Experimental 8-bit counters used as an additional search heuristic during |
| // coverage-guided fuzzing. |
| // The counters are not thread-friendly: |
| // - contention on these counters may cause significant slowdown; |
| // - the counter updates are racy and the results may be inaccurate. |
| // They are also inaccurate due to 8-bit integer overflow. |
| static cl::opt<bool> ClUse8bitCounters("sanitizer-coverage-8bit-counters", |
| cl::desc("Experimental 8-bit counters"), |
| cl::Hidden, cl::init(false)); |
| |
| namespace { |
| |
| SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) { |
| SanitizerCoverageOptions Res; |
| switch (LegacyCoverageLevel) { |
| case 0: |
| Res.CoverageType = SanitizerCoverageOptions::SCK_None; |
| break; |
| case 1: |
| Res.CoverageType = SanitizerCoverageOptions::SCK_Function; |
| break; |
| case 2: |
| Res.CoverageType = SanitizerCoverageOptions::SCK_BB; |
| break; |
| case 3: |
| Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; |
| break; |
| case 4: |
| Res.CoverageType = SanitizerCoverageOptions::SCK_Edge; |
| Res.IndirectCalls = true; |
| break; |
| } |
| return Res; |
| } |
| |
| SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) { |
| // Sets CoverageType and IndirectCalls. |
| SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel); |
| Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType); |
| Options.IndirectCalls |= CLOpts.IndirectCalls; |
| Options.TraceBB |= ClExperimentalTracing; |
| Options.TraceCmp |= ClExperimentalCMPTracing; |
| Options.Use8bitCounters |= ClUse8bitCounters; |
| Options.TracePC |= ClExperimentalTracePC; |
| return Options; |
| } |
| |
| class SanitizerCoverageModule : public ModulePass { |
| public: |
| SanitizerCoverageModule( |
| const SanitizerCoverageOptions &Options = SanitizerCoverageOptions()) |
| : ModulePass(ID), Options(OverrideFromCL(Options)) { |
| initializeSanitizerCoverageModulePass(*PassRegistry::getPassRegistry()); |
| } |
| bool runOnModule(Module &M) override; |
| bool runOnFunction(Function &F); |
| static char ID; // Pass identification, replacement for typeid |
| const char *getPassName() const override { return "SanitizerCoverageModule"; } |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| AU.addRequired<DominatorTreeWrapperPass>(); |
| AU.addRequired<PostDominatorTreeWrapperPass>(); |
| } |
| |
| private: |
| void InjectCoverageForIndirectCalls(Function &F, |
| ArrayRef<Instruction *> IndirCalls); |
| void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets); |
| void InjectTraceForSwitch(Function &F, |
| ArrayRef<Instruction *> SwitchTraceTargets); |
| bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks); |
| void SetNoSanitizeMetadata(Instruction *I); |
| void InjectCoverageAtBlock(Function &F, BasicBlock &BB, bool UseCalls); |
| unsigned NumberOfInstrumentedBlocks() { |
| return SanCovFunction->getNumUses() + |
| SanCovWithCheckFunction->getNumUses() + SanCovTraceBB->getNumUses() + |
| SanCovTraceEnter->getNumUses(); |
| } |
| Function *SanCovFunction; |
| Function *SanCovWithCheckFunction; |
| Function *SanCovIndirCallFunction, *SanCovTracePCIndir; |
| Function *SanCovTraceEnter, *SanCovTraceBB, *SanCovTracePC; |
| Function *SanCovTraceCmpFunction; |
| Function *SanCovTraceSwitchFunction; |
| InlineAsm *EmptyAsm; |
| Type *IntptrTy, *Int64Ty, *Int64PtrTy; |
| Module *CurModule; |
| LLVMContext *C; |
| const DataLayout *DL; |
| |
| GlobalVariable *GuardArray; |
| GlobalVariable *EightBitCounterArray; |
| |
| SanitizerCoverageOptions Options; |
| }; |
| |
| } // namespace |
| |
| bool SanitizerCoverageModule::runOnModule(Module &M) { |
| if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) |
| return false; |
| C = &(M.getContext()); |
| DL = &M.getDataLayout(); |
| CurModule = &M; |
| IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); |
| Type *VoidTy = Type::getVoidTy(*C); |
| IRBuilder<> IRB(*C); |
| Type *Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); |
| Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); |
| Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); |
| Int64Ty = IRB.getInt64Ty(); |
| |
| SanCovFunction = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovName, VoidTy, Int32PtrTy, nullptr)); |
| SanCovWithCheckFunction = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovWithCheckName, VoidTy, Int32PtrTy, nullptr)); |
| SanCovTracePCIndir = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy, nullptr)); |
| SanCovIndirCallFunction = |
| checkSanitizerInterfaceFunction(M.getOrInsertFunction( |
| SanCovIndirCallName, VoidTy, IntptrTy, IntptrTy, nullptr)); |
| SanCovTraceCmpFunction = |
| checkSanitizerInterfaceFunction(M.getOrInsertFunction( |
| SanCovTraceCmpName, VoidTy, Int64Ty, Int64Ty, Int64Ty, nullptr)); |
| SanCovTraceSwitchFunction = |
| checkSanitizerInterfaceFunction(M.getOrInsertFunction( |
| SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy, nullptr)); |
| |
| // We insert an empty inline asm after cov callbacks to avoid callback merge. |
| EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false), |
| StringRef(""), StringRef(""), |
| /*hasSideEffects=*/true); |
| |
| SanCovTracePC = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovTracePCName, VoidTy, nullptr)); |
| SanCovTraceEnter = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovTraceEnterName, VoidTy, Int32PtrTy, nullptr)); |
| SanCovTraceBB = checkSanitizerInterfaceFunction( |
| M.getOrInsertFunction(SanCovTraceBBName, VoidTy, Int32PtrTy, nullptr)); |
| |
| // At this point we create a dummy array of guards because we don't |
| // know how many elements we will need. |
| Type *Int32Ty = IRB.getInt32Ty(); |
| Type *Int8Ty = IRB.getInt8Ty(); |
| |
| GuardArray = |
| new GlobalVariable(M, Int32Ty, false, GlobalValue::ExternalLinkage, |
| nullptr, "__sancov_gen_cov_tmp"); |
| if (Options.Use8bitCounters) |
| EightBitCounterArray = |
| new GlobalVariable(M, Int8Ty, false, GlobalVariable::ExternalLinkage, |
| nullptr, "__sancov_gen_cov_tmp"); |
| |
| for (auto &F : M) |
| runOnFunction(F); |
| |
| auto N = NumberOfInstrumentedBlocks(); |
| |
| // Now we know how many elements we need. Create an array of guards |
| // with one extra element at the beginning for the size. |
| Type *Int32ArrayNTy = ArrayType::get(Int32Ty, N + 1); |
| GlobalVariable *RealGuardArray = new GlobalVariable( |
| M, Int32ArrayNTy, false, GlobalValue::PrivateLinkage, |
| Constant::getNullValue(Int32ArrayNTy), "__sancov_gen_cov"); |
| |
| // Replace the dummy array with the real one. |
| GuardArray->replaceAllUsesWith( |
| IRB.CreatePointerCast(RealGuardArray, Int32PtrTy)); |
| GuardArray->eraseFromParent(); |
| |
| GlobalVariable *RealEightBitCounterArray; |
| if (Options.Use8bitCounters) { |
| // Make sure the array is 16-aligned. |
| static const int CounterAlignment = 16; |
| Type *Int8ArrayNTy = ArrayType::get(Int8Ty, alignTo(N, CounterAlignment)); |
| RealEightBitCounterArray = new GlobalVariable( |
| M, Int8ArrayNTy, false, GlobalValue::PrivateLinkage, |
| Constant::getNullValue(Int8ArrayNTy), "__sancov_gen_cov_counter"); |
| RealEightBitCounterArray->setAlignment(CounterAlignment); |
| EightBitCounterArray->replaceAllUsesWith( |
| IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy)); |
| EightBitCounterArray->eraseFromParent(); |
| } |
| |
| // Create variable for module (compilation unit) name |
| Constant *ModNameStrConst = |
| ConstantDataArray::getString(M.getContext(), M.getName(), true); |
| GlobalVariable *ModuleName = |
| new GlobalVariable(M, ModNameStrConst->getType(), true, |
| GlobalValue::PrivateLinkage, ModNameStrConst); |
| |
| if (!Options.TracePC) { |
| Function *CtorFunc; |
| std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( |
| M, SanCovModuleCtorName, SanCovModuleInitName, |
| {Int32PtrTy, IntptrTy, Int8PtrTy, Int8PtrTy}, |
| {IRB.CreatePointerCast(RealGuardArray, Int32PtrTy), |
| ConstantInt::get(IntptrTy, N), |
| Options.Use8bitCounters |
| ? IRB.CreatePointerCast(RealEightBitCounterArray, Int8PtrTy) |
| : Constant::getNullValue(Int8PtrTy), |
| IRB.CreatePointerCast(ModuleName, Int8PtrTy)}); |
| |
| appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); |
| } |
| |
| return true; |
| } |
| |
| // True if block has successors and it dominates all of them. |
| static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) { |
| if (succ_begin(BB) == succ_end(BB)) |
| return false; |
| |
| for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) { |
| if (!DT->dominates(BB, SUCC)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // True if block has predecessors and it postdominates all of them. |
| static bool isFullPostDominator(const BasicBlock *BB, |
| const PostDominatorTree *PDT) { |
| if (pred_begin(BB) == pred_end(BB)) |
| return false; |
| |
| for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) { |
| if (!PDT->dominates(BB, PRED)) |
| return false; |
| } |
| |
| return true; |
| } |
| |
| static bool shouldInstrumentBlock(const Function& F, const BasicBlock *BB, const DominatorTree *DT, |
| const PostDominatorTree *PDT) { |
| if (!ClPruneBlocks || &F.getEntryBlock() == BB) |
| return true; |
| |
| return !(isFullDominator(BB, DT) || isFullPostDominator(BB, PDT)); |
| } |
| |
| bool SanitizerCoverageModule::runOnFunction(Function &F) { |
| if (F.empty()) |
| return false; |
| if (F.getName().find(".module_ctor") != std::string::npos) |
| return false; // Should not instrument sanitizer init functions. |
| // Don't instrument functions using SEH for now. Splitting basic blocks like |
| // we do for coverage breaks WinEHPrepare. |
| // FIXME: Remove this when SEH no longer uses landingpad pattern matching. |
| if (F.hasPersonalityFn() && |
| isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn()))) |
| return false; |
| if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) |
| SplitAllCriticalEdges(F); |
| SmallVector<Instruction *, 8> IndirCalls; |
| SmallVector<BasicBlock *, 16> BlocksToInstrument; |
| SmallVector<Instruction *, 8> CmpTraceTargets; |
| SmallVector<Instruction *, 8> SwitchTraceTargets; |
| |
| const DominatorTree *DT = |
| &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); |
| const PostDominatorTree *PDT = |
| &getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree(); |
| |
| for (auto &BB : F) { |
| if (shouldInstrumentBlock(F, &BB, DT, PDT)) |
| BlocksToInstrument.push_back(&BB); |
| for (auto &Inst : BB) { |
| if (Options.IndirectCalls) { |
| CallSite CS(&Inst); |
| if (CS && !CS.getCalledFunction()) |
| IndirCalls.push_back(&Inst); |
| } |
| if (Options.TraceCmp) { |
| if (isa<ICmpInst>(&Inst)) |
| CmpTraceTargets.push_back(&Inst); |
| if (isa<SwitchInst>(&Inst)) |
| SwitchTraceTargets.push_back(&Inst); |
| } |
| } |
| } |
| |
| InjectCoverage(F, BlocksToInstrument); |
| InjectCoverageForIndirectCalls(F, IndirCalls); |
| InjectTraceForCmp(F, CmpTraceTargets); |
| InjectTraceForSwitch(F, SwitchTraceTargets); |
| return true; |
| } |
| |
| bool SanitizerCoverageModule::InjectCoverage(Function &F, |
| ArrayRef<BasicBlock *> AllBlocks) { |
| switch (Options.CoverageType) { |
| case SanitizerCoverageOptions::SCK_None: |
| return false; |
| case SanitizerCoverageOptions::SCK_Function: |
| InjectCoverageAtBlock(F, F.getEntryBlock(), false); |
| return true; |
| default: { |
| bool UseCalls = ClCoverageBlockThreshold < AllBlocks.size(); |
| for (auto BB : AllBlocks) |
| InjectCoverageAtBlock(F, *BB, UseCalls); |
| return true; |
| } |
| } |
| } |
| |
| // On every indirect call we call a run-time function |
| // __sanitizer_cov_indir_call* with two parameters: |
| // - callee address, |
| // - global cache array that contains CacheSize pointers (zero-initialized). |
| // The cache is used to speed up recording the caller-callee pairs. |
| // The address of the caller is passed implicitly via caller PC. |
| // CacheSize is encoded in the name of the run-time function. |
| void SanitizerCoverageModule::InjectCoverageForIndirectCalls( |
| Function &F, ArrayRef<Instruction *> IndirCalls) { |
| if (IndirCalls.empty()) |
| return; |
| const int CacheSize = 16; |
| const int CacheAlignment = 64; // Align for better performance. |
| Type *Ty = ArrayType::get(IntptrTy, CacheSize); |
| for (auto I : IndirCalls) { |
| IRBuilder<> IRB(I); |
| CallSite CS(I); |
| Value *Callee = CS.getCalledValue(); |
| if (isa<InlineAsm>(Callee)) |
| continue; |
| GlobalVariable *CalleeCache = new GlobalVariable( |
| *F.getParent(), Ty, false, GlobalValue::PrivateLinkage, |
| Constant::getNullValue(Ty), "__sancov_gen_callee_cache"); |
| CalleeCache->setAlignment(CacheAlignment); |
| if (Options.TracePC) |
| IRB.CreateCall(SanCovTracePCIndir, |
| IRB.CreatePointerCast(Callee, IntptrTy)); |
| else |
| IRB.CreateCall(SanCovIndirCallFunction, |
| {IRB.CreatePointerCast(Callee, IntptrTy), |
| IRB.CreatePointerCast(CalleeCache, IntptrTy)}); |
| } |
| } |
| |
| // For every switch statement we insert a call: |
| // __sanitizer_cov_trace_switch(CondValue, |
| // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... }) |
| |
| void SanitizerCoverageModule::InjectTraceForSwitch( |
| Function &, ArrayRef<Instruction *> SwitchTraceTargets) { |
| for (auto I : SwitchTraceTargets) { |
| if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) { |
| IRBuilder<> IRB(I); |
| SmallVector<Constant *, 16> Initializers; |
| Value *Cond = SI->getCondition(); |
| if (Cond->getType()->getScalarSizeInBits() > |
| Int64Ty->getScalarSizeInBits()) |
| continue; |
| Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases())); |
| Initializers.push_back( |
| ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits())); |
| if (Cond->getType()->getScalarSizeInBits() < |
| Int64Ty->getScalarSizeInBits()) |
| Cond = IRB.CreateIntCast(Cond, Int64Ty, false); |
| for (auto It : SI->cases()) { |
| Constant *C = It.getCaseValue(); |
| if (C->getType()->getScalarSizeInBits() < |
| Int64Ty->getScalarSizeInBits()) |
| C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty); |
| Initializers.push_back(C); |
| } |
| ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size()); |
| GlobalVariable *GV = new GlobalVariable( |
| *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage, |
| ConstantArray::get(ArrayOfInt64Ty, Initializers), |
| "__sancov_gen_cov_switch_values"); |
| IRB.CreateCall(SanCovTraceSwitchFunction, |
| {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)}); |
| } |
| } |
| } |
| |
| void SanitizerCoverageModule::InjectTraceForCmp( |
| Function &, ArrayRef<Instruction *> CmpTraceTargets) { |
| for (auto I : CmpTraceTargets) { |
| if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) { |
| IRBuilder<> IRB(ICMP); |
| Value *A0 = ICMP->getOperand(0); |
| Value *A1 = ICMP->getOperand(1); |
| if (!A0->getType()->isIntegerTy()) |
| continue; |
| uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType()); |
| // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); |
| IRB.CreateCall( |
| SanCovTraceCmpFunction, |
| {ConstantInt::get(Int64Ty, (TypeSize << 32) | ICMP->getPredicate()), |
| IRB.CreateIntCast(A0, Int64Ty, true), |
| IRB.CreateIntCast(A1, Int64Ty, true)}); |
| } |
| } |
| } |
| |
| void SanitizerCoverageModule::SetNoSanitizeMetadata(Instruction *I) { |
| I->setMetadata(I->getModule()->getMDKindID("nosanitize"), |
| MDNode::get(*C, None)); |
| } |
| |
| void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB, |
| bool UseCalls) { |
| // Don't insert coverage for unreachable blocks: we will never call |
| // __sanitizer_cov() for them, so counting them in |
| // NumberOfInstrumentedBlocks() might complicate calculation of code coverage |
| // percentage. Also, unreachable instructions frequently have no debug |
| // locations. |
| if (isa<UnreachableInst>(BB.getTerminator())) |
| return; |
| BasicBlock::iterator IP = BB.getFirstInsertionPt(); |
| |
| bool IsEntryBB = &BB == &F.getEntryBlock(); |
| DebugLoc EntryLoc; |
| if (IsEntryBB) { |
| if (auto SP = F.getSubprogram()) |
| EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP); |
| // Keep static allocas and llvm.localescape calls in the entry block. Even |
| // if we aren't splitting the block, it's nice for allocas to be before |
| // calls. |
| IP = PrepareToSplitEntryBlock(BB, IP); |
| } else { |
| EntryLoc = IP->getDebugLoc(); |
| } |
| |
| IRBuilder<> IRB(&*IP); |
| IRB.SetCurrentDebugLocation(EntryLoc); |
| Value *GuardP = IRB.CreateAdd( |
| IRB.CreatePointerCast(GuardArray, IntptrTy), |
| ConstantInt::get(IntptrTy, (1 + NumberOfInstrumentedBlocks()) * 4)); |
| Type *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); |
| GuardP = IRB.CreateIntToPtr(GuardP, Int32PtrTy); |
| if (Options.TracePC) { |
| IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC. |
| IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. |
| } else if (Options.TraceBB) { |
| IRB.CreateCall(IsEntryBB ? SanCovTraceEnter : SanCovTraceBB, GuardP); |
| } else if (UseCalls) { |
| IRB.CreateCall(SanCovWithCheckFunction, GuardP); |
| } else { |
| LoadInst *Load = IRB.CreateLoad(GuardP); |
| Load->setAtomic(AtomicOrdering::Monotonic); |
| Load->setAlignment(4); |
| SetNoSanitizeMetadata(Load); |
| Value *Cmp = |
| IRB.CreateICmpSGE(Constant::getNullValue(Load->getType()), Load); |
| Instruction *Ins = SplitBlockAndInsertIfThen( |
| Cmp, &*IP, false, MDBuilder(*C).createBranchWeights(1, 100000)); |
| IRB.SetInsertPoint(Ins); |
| IRB.SetCurrentDebugLocation(EntryLoc); |
| // __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC. |
| IRB.CreateCall(SanCovFunction, GuardP); |
| IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. |
| } |
| |
| if (Options.Use8bitCounters) { |
| IRB.SetInsertPoint(&*IP); |
| Value *P = IRB.CreateAdd( |
| IRB.CreatePointerCast(EightBitCounterArray, IntptrTy), |
| ConstantInt::get(IntptrTy, NumberOfInstrumentedBlocks() - 1)); |
| P = IRB.CreateIntToPtr(P, IRB.getInt8PtrTy()); |
| LoadInst *LI = IRB.CreateLoad(P); |
| Value *Inc = IRB.CreateAdd(LI, ConstantInt::get(IRB.getInt8Ty(), 1)); |
| StoreInst *SI = IRB.CreateStore(Inc, P); |
| SetNoSanitizeMetadata(LI); |
| SetNoSanitizeMetadata(SI); |
| } |
| } |
| |
| char SanitizerCoverageModule::ID = 0; |
| INITIALIZE_PASS_BEGIN(SanitizerCoverageModule, "sancov", |
| "SanitizerCoverage: TODO." |
| "ModulePass", |
| false, false) |
| INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass) |
| INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass) |
| INITIALIZE_PASS_END(SanitizerCoverageModule, "sancov", |
| "SanitizerCoverage: TODO." |
| "ModulePass", |
| false, false) |
| ModulePass *llvm::createSanitizerCoverageModulePass( |
| const SanitizerCoverageOptions &Options) { |
| return new SanitizerCoverageModule(Options); |
| } |
