| //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Coverage instrumentation done on LLVM IR level, works with Sanitizers. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #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/Constant.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/DebugInfo.h" |
| #include "llvm/IR/Dominators.h" |
| #include "llvm/IR/Function.h" |
| #include "llvm/IR/GlobalVariable.h" |
| #include "llvm/IR/IRBuilder.h" |
| #include "llvm/IR/InlineAsm.h" |
| #include "llvm/IR/IntrinsicInst.h" |
| #include "llvm/IR/Intrinsics.h" |
| #include "llvm/IR/LLVMContext.h" |
| #include "llvm/IR/MDBuilder.h" |
| #include "llvm/IR/Mangler.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/Utils/BasicBlockUtils.h" |
| #include "llvm/Transforms/Utils/ModuleUtils.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "sancov" |
| |
| static const char *const SanCovTracePCIndirName = |
| "__sanitizer_cov_trace_pc_indir"; |
| static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc"; |
| static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1"; |
| static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2"; |
| static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4"; |
| static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8"; |
| static const char *const SanCovTraceConstCmp1 = |
| "__sanitizer_cov_trace_const_cmp1"; |
| static const char *const SanCovTraceConstCmp2 = |
| "__sanitizer_cov_trace_const_cmp2"; |
| static const char *const SanCovTraceConstCmp4 = |
| "__sanitizer_cov_trace_const_cmp4"; |
| static const char *const SanCovTraceConstCmp8 = |
| "__sanitizer_cov_trace_const_cmp8"; |
| static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4"; |
| static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8"; |
| static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep"; |
| static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch"; |
| static const char *const SanCovModuleCtorTracePcGuardName = |
| "sancov.module_ctor_trace_pc_guard"; |
| static const char *const SanCovModuleCtor8bitCountersName = |
| "sancov.module_ctor_8bit_counters"; |
| static const uint64_t SanCtorAndDtorPriority = 2; |
| |
| static const char *const SanCovTracePCGuardName = |
| "__sanitizer_cov_trace_pc_guard"; |
| static const char *const SanCovTracePCGuardInitName = |
| "__sanitizer_cov_trace_pc_guard_init"; |
| static const char *const SanCov8bitCountersInitName = |
| "__sanitizer_cov_8bit_counters_init"; |
| static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init"; |
| |
| static const char *const SanCovGuardsSectionName = "sancov_guards"; |
| static const char *const SanCovCountersSectionName = "sancov_cntrs"; |
| static const char *const SanCovPCsSectionName = "sancov_pcs"; |
| |
| static const char *const SanCovLowestStackName = "__sancov_lowest_stack"; |
| |
| 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"), |
| cl::Hidden, cl::init(0)); |
| |
| static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc", |
| cl::desc("Experimental pc tracing"), cl::Hidden, |
| cl::init(false)); |
| |
| static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard", |
| cl::desc("pc tracing with a guard"), |
| cl::Hidden, cl::init(false)); |
| |
| // If true, we create a global variable that contains PCs of all instrumented |
| // BBs, put this global into a named section, and pass this section's bounds |
| // to __sanitizer_cov_pcs_init. |
| // This way the coverage instrumentation does not need to acquire the PCs |
| // at run-time. Works with trace-pc-guard and inline-8bit-counters. |
| static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table", |
| cl::desc("create a static PC table"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> |
| ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters", |
| cl::desc("increments 8-bit counter for every edge"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> |
| ClCMPTracing("sanitizer-coverage-trace-compares", |
| cl::desc("Tracing of CMP and similar instructions"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs", |
| cl::desc("Tracing of DIV instructions"), |
| cl::Hidden, cl::init(false)); |
| |
| static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps", |
| cl::desc("Tracing of GEP 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)); |
| |
| static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth", |
| cl::desc("max stack depth tracing"), |
| 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.TraceCmp |= ClCMPTracing; |
| Options.TraceDiv |= ClDIVTracing; |
| Options.TraceGep |= ClGEPTracing; |
| Options.TracePC |= ClTracePC; |
| Options.TracePCGuard |= ClTracePCGuard; |
| Options.Inline8bitCounters |= ClInline8bitCounters; |
| Options.PCTable |= ClCreatePCTable; |
| Options.NoPrune |= !ClPruneBlocks; |
| Options.StackDepth |= ClStackDepth; |
| if (!Options.TracePCGuard && !Options.TracePC && |
| !Options.Inline8bitCounters && !Options.StackDepth) |
| Options.TracePCGuard = true; // TracePCGuard is default. |
| 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 |
| StringRef 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 InjectTraceForDiv(Function &F, |
| ArrayRef<BinaryOperator *> DivTraceTargets); |
| void InjectTraceForGep(Function &F, |
| ArrayRef<GetElementPtrInst *> GepTraceTargets); |
| void InjectTraceForSwitch(Function &F, |
| ArrayRef<Instruction *> SwitchTraceTargets); |
| bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks, |
| bool IsLeafFunc = true); |
| GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements, |
| Function &F, Type *Ty, |
| const char *Section); |
| GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks); |
| void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks); |
| void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx, |
| bool IsLeafFunc = true); |
| Function *CreateInitCallsForSections(Module &M, const char *CtorName, |
| const char *InitFunctionName, Type *Ty, |
| const char *Section); |
| std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section, |
| Type *Ty); |
| |
| void SetNoSanitizeMetadata(Instruction *I) { |
| I->setMetadata(I->getModule()->getMDKindID("nosanitize"), |
| MDNode::get(*C, None)); |
| } |
| |
| std::string getSectionName(const std::string &Section) const; |
| std::string getSectionStart(const std::string &Section) const; |
| std::string getSectionEnd(const std::string &Section) const; |
| FunctionCallee SanCovTracePCIndir; |
| FunctionCallee SanCovTracePC, SanCovTracePCGuard; |
| FunctionCallee SanCovTraceCmpFunction[4]; |
| FunctionCallee SanCovTraceConstCmpFunction[4]; |
| FunctionCallee SanCovTraceDivFunction[2]; |
| FunctionCallee SanCovTraceGepFunction; |
| FunctionCallee SanCovTraceSwitchFunction; |
| GlobalVariable *SanCovLowestStack; |
| InlineAsm *EmptyAsm; |
| Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy, |
| *Int16Ty, *Int8Ty, *Int8PtrTy; |
| Module *CurModule; |
| std::string CurModuleUniqueId; |
| Triple TargetTriple; |
| LLVMContext *C; |
| const DataLayout *DL; |
| |
| GlobalVariable *FunctionGuardArray; // for trace-pc-guard. |
| GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters. |
| GlobalVariable *FunctionPCsArray; // for pc-table. |
| SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed; |
| SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed; |
| |
| SanitizerCoverageOptions Options; |
| }; |
| |
| } // namespace |
| |
| std::pair<Value *, Value *> |
| SanitizerCoverageModule::CreateSecStartEnd(Module &M, const char *Section, |
| Type *Ty) { |
| GlobalVariable *SecStart = |
| new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr, |
| getSectionStart(Section)); |
| SecStart->setVisibility(GlobalValue::HiddenVisibility); |
| GlobalVariable *SecEnd = |
| new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, |
| nullptr, getSectionEnd(Section)); |
| SecEnd->setVisibility(GlobalValue::HiddenVisibility); |
| IRBuilder<> IRB(M.getContext()); |
| Value *SecEndPtr = IRB.CreatePointerCast(SecEnd, Ty); |
| if (!TargetTriple.isOSBinFormatCOFF()) |
| return std::make_pair(IRB.CreatePointerCast(SecStart, Ty), SecEndPtr); |
| |
| // Account for the fact that on windows-msvc __start_* symbols actually |
| // point to a uint64_t before the start of the array. |
| auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy); |
| auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr, |
| ConstantInt::get(IntptrTy, sizeof(uint64_t))); |
| return std::make_pair(IRB.CreatePointerCast(GEP, Ty), SecEndPtr); |
| } |
| |
| Function *SanitizerCoverageModule::CreateInitCallsForSections( |
| Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty, |
| const char *Section) { |
| auto SecStartEnd = CreateSecStartEnd(M, Section, Ty); |
| auto SecStart = SecStartEnd.first; |
| auto SecEnd = SecStartEnd.second; |
| Function *CtorFunc; |
| std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions( |
| M, CtorName, InitFunctionName, {Ty, Ty}, {SecStart, SecEnd}); |
| assert(CtorFunc->getName() == CtorName); |
| |
| if (TargetTriple.supportsCOMDAT()) { |
| // Use comdat to dedup CtorFunc. |
| CtorFunc->setComdat(M.getOrInsertComdat(CtorName)); |
| appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc); |
| } else { |
| appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority); |
| } |
| |
| if (TargetTriple.isOSBinFormatCOFF()) { |
| // In COFF files, if the contructors are set as COMDAT (they are because |
| // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced |
| // functions and data) is used, the constructors get stripped. To prevent |
| // this, give the constructors weak ODR linkage and ensure the linker knows |
| // to include the sancov constructor. This way the linker can deduplicate |
| // the constructors but always leave one copy. |
| CtorFunc->setLinkage(GlobalValue::WeakODRLinkage); |
| appendToUsed(M, CtorFunc); |
| } |
| return CtorFunc; |
| } |
| |
| bool SanitizerCoverageModule::runOnModule(Module &M) { |
| if (Options.CoverageType == SanitizerCoverageOptions::SCK_None) |
| return false; |
| C = &(M.getContext()); |
| DL = &M.getDataLayout(); |
| CurModule = &M; |
| CurModuleUniqueId = getUniqueModuleId(CurModule); |
| TargetTriple = Triple(M.getTargetTriple()); |
| FunctionGuardArray = nullptr; |
| Function8bitCounterArray = nullptr; |
| FunctionPCsArray = nullptr; |
| IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits()); |
| IntptrPtrTy = PointerType::getUnqual(IntptrTy); |
| Type *VoidTy = Type::getVoidTy(*C); |
| IRBuilder<> IRB(*C); |
| Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty()); |
| Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty()); |
| Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty()); |
| Int64Ty = IRB.getInt64Ty(); |
| Int32Ty = IRB.getInt32Ty(); |
| Int16Ty = IRB.getInt16Ty(); |
| Int8Ty = IRB.getInt8Ty(); |
| |
| SanCovTracePCIndir = |
| M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy); |
| // Make sure smaller parameters are zero-extended to i64 as required by the |
| // x86_64 ABI. |
| AttributeList SanCovTraceCmpZeroExtAL; |
| if (TargetTriple.getArch() == Triple::x86_64) { |
| SanCovTraceCmpZeroExtAL = |
| SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt); |
| SanCovTraceCmpZeroExtAL = |
| SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt); |
| } |
| |
| SanCovTraceCmpFunction[0] = |
| M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy, |
| IRB.getInt8Ty(), IRB.getInt8Ty()); |
| SanCovTraceCmpFunction[1] = |
| M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy, |
| IRB.getInt16Ty(), IRB.getInt16Ty()); |
| SanCovTraceCmpFunction[2] = |
| M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy, |
| IRB.getInt32Ty(), IRB.getInt32Ty()); |
| SanCovTraceCmpFunction[3] = |
| M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty); |
| |
| SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction( |
| SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty); |
| SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction( |
| SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty); |
| SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction( |
| SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty); |
| SanCovTraceConstCmpFunction[3] = |
| M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty); |
| |
| { |
| AttributeList AL; |
| if (TargetTriple.getArch() == Triple::x86_64) |
| AL = AL.addParamAttribute(*C, 0, Attribute::ZExt); |
| SanCovTraceDivFunction[0] = |
| M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty()); |
| } |
| SanCovTraceDivFunction[1] = |
| M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty); |
| SanCovTraceGepFunction = |
| M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy); |
| SanCovTraceSwitchFunction = |
| M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy); |
| |
| Constant *SanCovLowestStackConstant = |
| M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy); |
| SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant); |
| if (!SanCovLowestStack) { |
| C->emitError(StringRef("'") + SanCovLowestStackName + |
| "' should not be declared by the user"); |
| return true; |
| } |
| SanCovLowestStack->setThreadLocalMode( |
| GlobalValue::ThreadLocalMode::InitialExecTLSModel); |
| if (Options.StackDepth && !SanCovLowestStack->isDeclaration()) |
| SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy)); |
| |
| // 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 = M.getOrInsertFunction(SanCovTracePCName, VoidTy); |
| SanCovTracePCGuard = |
| M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy); |
| |
| for (auto &F : M) |
| runOnFunction(F); |
| |
| Function *Ctor = nullptr; |
| |
| if (FunctionGuardArray) |
| Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName, |
| SanCovTracePCGuardInitName, Int32PtrTy, |
| SanCovGuardsSectionName); |
| if (Function8bitCounterArray) |
| Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName, |
| SanCov8bitCountersInitName, Int8PtrTy, |
| SanCovCountersSectionName); |
| if (Ctor && Options.PCTable) { |
| auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy); |
| FunctionCallee InitFunction = declareSanitizerInitFunction( |
| M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy}); |
| IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator()); |
| IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second}); |
| } |
| // We don't reference these arrays directly in any of our runtime functions, |
| // so we need to prevent them from being dead stripped. |
| if (TargetTriple.isOSBinFormatMachO()) |
| appendToUsed(M, GlobalsToAppendToUsed); |
| appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed); |
| 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, |
| const SanitizerCoverageOptions &Options) { |
| // Don't insert coverage for blocks containing nothing but unreachable: 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->getFirstNonPHIOrDbgOrLifetime())) |
| return false; |
| |
| // Don't insert coverage into blocks without a valid insertion point |
| // (catchswitch blocks). |
| if (BB->getFirstInsertionPt() == BB->end()) |
| return false; |
| |
| if (Options.NoPrune || &F.getEntryBlock() == BB) |
| return true; |
| |
| if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function && |
| &F.getEntryBlock() != BB) |
| return false; |
| |
| // Do not instrument full dominators, or full post-dominators with multiple |
| // predecessors. |
| return !isFullDominator(BB, DT) |
| && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor()); |
| } |
| |
| |
| // Returns true iff From->To is a backedge. |
| // A twist here is that we treat From->To as a backedge if |
| // * To dominates From or |
| // * To->UniqueSuccessor dominates From |
| static bool IsBackEdge(BasicBlock *From, BasicBlock *To, |
| const DominatorTree *DT) { |
| if (DT->dominates(To, From)) |
| return true; |
| if (auto Next = To->getUniqueSuccessor()) |
| if (DT->dominates(Next, From)) |
| return true; |
| return false; |
| } |
| |
| // Prunes uninteresting Cmp instrumentation: |
| // * CMP instructions that feed into loop backedge branch. |
| // |
| // Note that Cmp pruning is controlled by the same flag as the |
| // BB pruning. |
| static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT, |
| const SanitizerCoverageOptions &Options) { |
| if (!Options.NoPrune) |
| if (CMP->hasOneUse()) |
| if (auto BR = dyn_cast<BranchInst>(CMP->user_back())) |
| for (BasicBlock *B : BR->successors()) |
| if (IsBackEdge(BR->getParent(), B, DT)) |
| return false; |
| return true; |
| } |
| |
| 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. |
| if (F.getName().startswith("__sanitizer_")) |
| return false; // Don't instrument __sanitizer_* callbacks. |
| // Don't touch available_externally functions, their actual body is elewhere. |
| if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) |
| return false; |
| // Don't instrument MSVC CRT configuration helpers. They may run before normal |
| // initialization. |
| if (F.getName() == "__local_stdio_printf_options" || |
| F.getName() == "__local_stdio_scanf_options") |
| return false; |
| if (isa<UnreachableInst>(F.getEntryBlock().getTerminator())) |
| return false; |
| // 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, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests()); |
| SmallVector<Instruction *, 8> IndirCalls; |
| SmallVector<BasicBlock *, 16> BlocksToInstrument; |
| SmallVector<Instruction *, 8> CmpTraceTargets; |
| SmallVector<Instruction *, 8> SwitchTraceTargets; |
| SmallVector<BinaryOperator *, 8> DivTraceTargets; |
| SmallVector<GetElementPtrInst *, 8> GepTraceTargets; |
| |
| const DominatorTree *DT = |
| &getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(); |
| const PostDominatorTree *PDT = |
| &getAnalysis<PostDominatorTreeWrapperPass>(F).getPostDomTree(); |
| bool IsLeafFunc = true; |
| |
| for (auto &BB : F) { |
| if (shouldInstrumentBlock(F, &BB, DT, PDT, Options)) |
| 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 (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst)) |
| if (IsInterestingCmp(CMP, DT, Options)) |
| CmpTraceTargets.push_back(&Inst); |
| if (isa<SwitchInst>(&Inst)) |
| SwitchTraceTargets.push_back(&Inst); |
| } |
| if (Options.TraceDiv) |
| if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst)) |
| if (BO->getOpcode() == Instruction::SDiv || |
| BO->getOpcode() == Instruction::UDiv) |
| DivTraceTargets.push_back(BO); |
| if (Options.TraceGep) |
| if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst)) |
| GepTraceTargets.push_back(GEP); |
| if (Options.StackDepth) |
| if (isa<InvokeInst>(Inst) || |
| (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst))) |
| IsLeafFunc = false; |
| } |
| } |
| |
| InjectCoverage(F, BlocksToInstrument, IsLeafFunc); |
| InjectCoverageForIndirectCalls(F, IndirCalls); |
| InjectTraceForCmp(F, CmpTraceTargets); |
| InjectTraceForSwitch(F, SwitchTraceTargets); |
| InjectTraceForDiv(F, DivTraceTargets); |
| InjectTraceForGep(F, GepTraceTargets); |
| return true; |
| } |
| |
| GlobalVariable *SanitizerCoverageModule::CreateFunctionLocalArrayInSection( |
| size_t NumElements, Function &F, Type *Ty, const char *Section) { |
| ArrayType *ArrayTy = ArrayType::get(Ty, NumElements); |
| auto Array = new GlobalVariable( |
| *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage, |
| Constant::getNullValue(ArrayTy), "__sancov_gen_"); |
| |
| if (TargetTriple.supportsCOMDAT() && !F.isInterposable()) |
| if (auto Comdat = |
| GetOrCreateFunctionComdat(F, TargetTriple, CurModuleUniqueId)) |
| Array->setComdat(Comdat); |
| Array->setSection(getSectionName(Section)); |
| Array->setAlignment(Ty->isPointerTy() ? DL->getPointerSize() |
| : Ty->getPrimitiveSizeInBits() / 8); |
| GlobalsToAppendToUsed.push_back(Array); |
| GlobalsToAppendToCompilerUsed.push_back(Array); |
| MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F)); |
| Array->addMetadata(LLVMContext::MD_associated, *MD); |
| |
| return Array; |
| } |
| |
| GlobalVariable * |
| SanitizerCoverageModule::CreatePCArray(Function &F, |
| ArrayRef<BasicBlock *> AllBlocks) { |
| size_t N = AllBlocks.size(); |
| assert(N); |
| SmallVector<Constant *, 32> PCs; |
| IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt()); |
| for (size_t i = 0; i < N; i++) { |
| if (&F.getEntryBlock() == AllBlocks[i]) { |
| PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy)); |
| PCs.push_back((Constant *)IRB.CreateIntToPtr( |
| ConstantInt::get(IntptrTy, 1), IntptrPtrTy)); |
| } else { |
| PCs.push_back((Constant *)IRB.CreatePointerCast( |
| BlockAddress::get(AllBlocks[i]), IntptrPtrTy)); |
| PCs.push_back((Constant *)IRB.CreateIntToPtr( |
| ConstantInt::get(IntptrTy, 0), IntptrPtrTy)); |
| } |
| } |
| auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy, |
| SanCovPCsSectionName); |
| PCArray->setInitializer( |
| ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs)); |
| PCArray->setConstant(true); |
| |
| return PCArray; |
| } |
| |
| void SanitizerCoverageModule::CreateFunctionLocalArrays( |
| Function &F, ArrayRef<BasicBlock *> AllBlocks) { |
| if (Options.TracePCGuard) |
| FunctionGuardArray = CreateFunctionLocalArrayInSection( |
| AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName); |
| |
| if (Options.Inline8bitCounters) |
| Function8bitCounterArray = CreateFunctionLocalArrayInSection( |
| AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName); |
| |
| if (Options.PCTable) |
| FunctionPCsArray = CreatePCArray(F, AllBlocks); |
| } |
| |
| bool SanitizerCoverageModule::InjectCoverage(Function &F, |
| ArrayRef<BasicBlock *> AllBlocks, |
| bool IsLeafFunc) { |
| if (AllBlocks.empty()) return false; |
| CreateFunctionLocalArrays(F, AllBlocks); |
| for (size_t i = 0, N = AllBlocks.size(); i < N; i++) |
| InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc); |
| 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; |
| assert(Options.TracePC || Options.TracePCGuard || Options.Inline8bitCounters); |
| for (auto I : IndirCalls) { |
| IRBuilder<> IRB(I); |
| CallSite CS(I); |
| Value *Callee = CS.getCalledValue(); |
| if (isa<InlineAsm>(Callee)) |
| continue; |
| IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, 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); |
| } |
| llvm::sort(Initializers.begin() + 2, Initializers.end(), |
| [](const Constant *A, const Constant *B) { |
| return cast<ConstantInt>(A)->getLimitedValue() < |
| cast<ConstantInt>(B)->getLimitedValue(); |
| }); |
| 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::InjectTraceForDiv( |
| Function &, ArrayRef<BinaryOperator *> DivTraceTargets) { |
| for (auto BO : DivTraceTargets) { |
| IRBuilder<> IRB(BO); |
| Value *A1 = BO->getOperand(1); |
| if (isa<ConstantInt>(A1)) continue; |
| if (!A1->getType()->isIntegerTy()) |
| continue; |
| uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType()); |
| int CallbackIdx = TypeSize == 32 ? 0 : |
| TypeSize == 64 ? 1 : -1; |
| if (CallbackIdx < 0) continue; |
| auto Ty = Type::getIntNTy(*C, TypeSize); |
| IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx], |
| {IRB.CreateIntCast(A1, Ty, true)}); |
| } |
| } |
| |
| void SanitizerCoverageModule::InjectTraceForGep( |
| Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) { |
| for (auto GEP : GepTraceTargets) { |
| IRBuilder<> IRB(GEP); |
| for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I) |
| if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy()) |
| IRB.CreateCall(SanCovTraceGepFunction, |
| {IRB.CreateIntCast(*I, IntptrTy, true)}); |
| } |
| } |
| |
| 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()); |
| int CallbackIdx = TypeSize == 8 ? 0 : |
| TypeSize == 16 ? 1 : |
| TypeSize == 32 ? 2 : |
| TypeSize == 64 ? 3 : -1; |
| if (CallbackIdx < 0) continue; |
| // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1); |
| auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx]; |
| bool FirstIsConst = isa<ConstantInt>(A0); |
| bool SecondIsConst = isa<ConstantInt>(A1); |
| // If both are const, then we don't need such a comparison. |
| if (FirstIsConst && SecondIsConst) continue; |
| // If only one is const, then make it the first callback argument. |
| if (FirstIsConst || SecondIsConst) { |
| CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx]; |
| if (SecondIsConst) |
| std::swap(A0, A1); |
| } |
| |
| auto Ty = Type::getIntNTy(*C, TypeSize); |
| IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true), |
| IRB.CreateIntCast(A1, Ty, true)}); |
| } |
| } |
| } |
| |
| void SanitizerCoverageModule::InjectCoverageAtBlock(Function &F, BasicBlock &BB, |
| size_t Idx, |
| bool IsLeafFunc) { |
| 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); |
| if (Options.TracePC) { |
| IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC. |
| IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. |
| } |
| if (Options.TracePCGuard) { |
| auto GuardPtr = IRB.CreateIntToPtr( |
| IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy), |
| ConstantInt::get(IntptrTy, Idx * 4)), |
| Int32PtrTy); |
| IRB.CreateCall(SanCovTracePCGuard, GuardPtr); |
| IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge. |
| } |
| if (Options.Inline8bitCounters) { |
| auto CounterPtr = IRB.CreateGEP( |
| Function8bitCounterArray->getValueType(), Function8bitCounterArray, |
| {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)}); |
| auto Load = IRB.CreateLoad(Int8Ty, CounterPtr); |
| auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1)); |
| auto Store = IRB.CreateStore(Inc, CounterPtr); |
| SetNoSanitizeMetadata(Load); |
| SetNoSanitizeMetadata(Store); |
| } |
| if (Options.StackDepth && IsEntryBB && !IsLeafFunc) { |
| // Check stack depth. If it's the deepest so far, record it. |
| Function *GetFrameAddr = |
| Intrinsic::getDeclaration(F.getParent(), Intrinsic::frameaddress); |
| auto FrameAddrPtr = |
| IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)}); |
| auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy); |
| auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack); |
| auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack); |
| auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false); |
| IRBuilder<> ThenIRB(ThenTerm); |
| auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack); |
| SetNoSanitizeMetadata(LowestStack); |
| SetNoSanitizeMetadata(Store); |
| } |
| } |
| |
| std::string |
| SanitizerCoverageModule::getSectionName(const std::string &Section) const { |
| if (TargetTriple.isOSBinFormatCOFF()) { |
| if (Section == SanCovCountersSectionName) |
| return ".SCOV$CM"; |
| if (Section == SanCovPCsSectionName) |
| return ".SCOVP$M"; |
| return ".SCOV$GM"; // For SanCovGuardsSectionName. |
| } |
| if (TargetTriple.isOSBinFormatMachO()) |
| return "__DATA,__" + Section; |
| return "__" + Section; |
| } |
| |
| std::string |
| SanitizerCoverageModule::getSectionStart(const std::string &Section) const { |
| if (TargetTriple.isOSBinFormatMachO()) |
| return "\1section$start$__DATA$__" + Section; |
| return "__start___" + Section; |
| } |
| |
| std::string |
| SanitizerCoverageModule::getSectionEnd(const std::string &Section) const { |
| if (TargetTriple.isOSBinFormatMachO()) |
| return "\1section$end$__DATA$__" + Section; |
| return "__stop___" + Section; |
| } |
| |
| |
| 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); |
| } |
