X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FTransforms%2FInstrumentation%2FAddressSanitizer.cpp;h=623c4705061ef9cd316cf3edcdfb826a7433675a;hp=336802668ca5d4d42c897a8ba3b4734f7377fc87;hb=866ee52df37b5b2229bdae201f8d5ecad41d4326;hpb=f7b08226eb44458f6f38cbeaca527028803c725a diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp index 336802668ca..3f0db3630b9 100644 --- a/lib/Transforms/Instrumentation/AddressSanitizer.cpp +++ b/lib/Transforms/Instrumentation/AddressSanitizer.cpp @@ -13,65 +13,95 @@ // //===----------------------------------------------------------------------===// -#define DEBUG_TYPE "asan" - -#include "FunctionBlackList.h" -#include "llvm/Function.h" -#include "llvm/IRBuilder.h" -#include "llvm/InlineAsm.h" -#include "llvm/IntrinsicInst.h" -#include "llvm/LLVMContext.h" -#include "llvm/Module.h" -#include "llvm/Type.h" +#include "llvm/Transforms/Instrumentation.h" #include "llvm/ADT/ArrayRef.h" -#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/DenseSet.h" +#include "llvm/ADT/DepthFirstIterator.h" #include "llvm/ADT/SmallSet.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Statistic.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/Triple.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/DIBuilder.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/IRBuilder.h" +#include "llvm/IR/InlineAsm.h" +#include "llvm/IR/InstVisitor.h" +#include "llvm/IR/IntrinsicInst.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/DataTypes.h" #include "llvm/Support/Debug.h" -#include "llvm/Support/raw_ostream.h" -#include "llvm/Support/system_error.h" -#include "llvm/Target/TargetData.h" -#include "llvm/Target/TargetMachine.h" -#include "llvm/Transforms/Instrumentation.h" +#include "llvm/Support/Endian.h" +#include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Utils/ASanStackFrameLayout.h" #include "llvm/Transforms/Utils/BasicBlockUtils.h" +#include "llvm/Transforms/Utils/Cloning.h" +#include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Utils/ModuleUtils.h" - -#include #include +#include +#include using namespace llvm; +#define DEBUG_TYPE "asan" + static const uint64_t kDefaultShadowScale = 3; static const uint64_t kDefaultShadowOffset32 = 1ULL << 29; +static const uint64_t kIOSShadowOffset32 = 1ULL << 30; static const uint64_t kDefaultShadowOffset64 = 1ULL << 44; -static const uint64_t kDefaultShadowOffsetAndroid = 0; +static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G. +static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41; +static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000; +static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30; +static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46; +static const size_t kMinStackMallocSize = 1 << 6; // 64B static const size_t kMaxStackMallocSize = 1 << 16; // 64K static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3; static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E; -static const char *kAsanModuleCtorName = "asan.module_ctor"; -static const char *kAsanModuleDtorName = "asan.module_dtor"; -static const int kAsanCtorAndCtorPriority = 1; -static const char *kAsanReportErrorTemplate = "__asan_report_"; -static const char *kAsanRegisterGlobalsName = "__asan_register_globals"; -static const char *kAsanUnregisterGlobalsName = "__asan_unregister_globals"; -static const char *kAsanInitName = "__asan_init"; -static const char *kAsanHandleNoReturnName = "__asan_handle_no_return"; -static const char *kAsanMappingOffsetName = "__asan_mapping_offset"; -static const char *kAsanMappingScaleName = "__asan_mapping_scale"; -static const char *kAsanStackMallocName = "__asan_stack_malloc"; -static const char *kAsanStackFreeName = "__asan_stack_free"; - -static const int kAsanStackLeftRedzoneMagic = 0xf1; -static const int kAsanStackMidRedzoneMagic = 0xf2; -static const int kAsanStackRightRedzoneMagic = 0xf3; -static const int kAsanStackPartialRedzoneMagic = 0xf4; +static const char *const kAsanModuleCtorName = "asan.module_ctor"; +static const char *const kAsanModuleDtorName = "asan.module_dtor"; +static const uint64_t kAsanCtorAndDtorPriority = 1; +static const char *const kAsanReportErrorTemplate = "__asan_report_"; +static const char *const kAsanReportLoadN = "__asan_report_load_n"; +static const char *const kAsanReportStoreN = "__asan_report_store_n"; +static const char *const kAsanRegisterGlobalsName = "__asan_register_globals"; +static const char *const kAsanUnregisterGlobalsName = + "__asan_unregister_globals"; +static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init"; +static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init"; +static const char *const kAsanInitName = "__asan_init_v4"; +static const char *const kAsanCovModuleInitName = "__sanitizer_cov_module_init"; +static const char *const kAsanCovName = "__sanitizer_cov"; +static const char *const kAsanCovIndirCallName = "__sanitizer_cov_indir_call16"; +static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp"; +static const char *const kAsanPtrSub = "__sanitizer_ptr_sub"; +static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return"; +static const int kMaxAsanStackMallocSizeClass = 10; +static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_"; +static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_"; +static const char *const kAsanGenPrefix = "__asan_gen_"; +static const char *const kAsanPoisonStackMemoryName = + "__asan_poison_stack_memory"; +static const char *const kAsanUnpoisonStackMemoryName = + "__asan_unpoison_stack_memory"; + +static const char *const kAsanOptionDetectUAR = + "__asan_option_detect_stack_use_after_return"; + +#ifndef NDEBUG +static const int kAsanStackAfterReturnMagic = 0xf5; +#endif // Accesses sizes are powers of two: 1, 2, 4, 8, 16. static const size_t kNumberOfAccessSizes = 5; @@ -86,8 +116,8 @@ static cl::opt ClInstrumentWrites("asan-instrument-writes", static cl::opt ClInstrumentAtomics("asan-instrument-atomics", cl::desc("instrument atomic instructions (rmw, cmpxchg)"), cl::Hidden, cl::init(true)); -static cl::opt ClMergeCallbacks("asan-merge-callbacks", - cl::desc("merge __asan_report_ callbacks to create fewer BBs"), +static cl::opt ClAlwaysSlowPath("asan-always-slow-path", + cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden, cl::init(false)); // This flag limits the number of instructions to be instrumented // in any given BB. Normally, this should be set to unlimited (INT_MAX), @@ -100,26 +130,57 @@ static cl::opt ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb", // This flag may need to be replaced with -f[no]asan-stack. static cl::opt ClStack("asan-stack", cl::desc("Handle stack memory"), cl::Hidden, cl::init(true)); -// This flag may need to be replaced with -f[no]asan-use-after-return. static cl::opt ClUseAfterReturn("asan-use-after-return", - cl::desc("Check return-after-free"), cl::Hidden, cl::init(false)); + cl::desc("Check return-after-free"), cl::Hidden, cl::init(true)); // This flag may need to be replaced with -f[no]asan-globals. static cl::opt ClGlobals("asan-globals", cl::desc("Handle global objects"), cl::Hidden, cl::init(true)); -static cl::opt ClMemIntrin("asan-memintrin", - cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true)); -// This flag may need to be replaced with -fasan-blacklist. -static cl::opt ClBlackListFile("asan-blacklist", - cl::desc("File containing the list of functions to ignore " - "during instrumentation"), cl::Hidden); +static cl::opt ClCoverage("asan-coverage", + cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks, " + "3: all blocks and critical edges, " + "4: above plus indirect calls"), + cl::Hidden, cl::init(false)); +static cl::opt ClCoverageBlockThreshold("asan-coverage-block-threshold", + cl::desc("Add coverage instrumentation only to the entry block if there " + "are more than this number of blocks."), + cl::Hidden, cl::init(1500)); +static cl::opt ClInitializers("asan-initialization-order", + cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(true)); +static cl::opt ClInvalidPointerPairs("asan-detect-invalid-pointer-pair", + cl::desc("Instrument <, <=, >, >=, - with pointer operands"), + cl::Hidden, cl::init(false)); +static cl::opt ClRealignStack("asan-realign-stack", + cl::desc("Realign stack to the value of this flag (power of two)"), + cl::Hidden, cl::init(32)); +static cl::opt ClInstrumentationWithCallsThreshold( + "asan-instrumentation-with-call-threshold", + cl::desc("If the function being instrumented contains more than " + "this number of memory accesses, use callbacks instead of " + "inline checks (-1 means never use callbacks)."), + cl::Hidden, cl::init(7000)); +static cl::opt ClMemoryAccessCallbackPrefix( + "asan-memory-access-callback-prefix", + cl::desc("Prefix for memory access callbacks"), cl::Hidden, + cl::init("__asan_")); + +// This is an experimental feature that will allow to choose between +// instrumented and non-instrumented code at link-time. +// If this option is on, just before instrumenting a function we create its +// clone; if the function is not changed by asan the clone is deleted. +// If we end up with a clone, we put the instrumented function into a section +// called "ASAN" and the uninstrumented function into a section called "NOASAN". +// +// This is still a prototype, we need to figure out a way to keep two copies of +// a function so that the linker can easily choose one of them. +static cl::opt ClKeepUninstrumented("asan-keep-uninstrumented-functions", + cl::desc("Keep uninstrumented copies of functions"), + cl::Hidden, cl::init(false)); // These flags allow to change the shadow mapping. // The shadow mapping looks like // Shadow = (Mem >> scale) + (1 << offset_log) static cl::opt ClMappingScale("asan-mapping-scale", cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0)); -static cl::opt ClMappingOffsetLog("asan-mapping-offset-log", - cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1)); // Optimization flags. Not user visible, used mostly for testing // and benchmarking the tool. @@ -131,6 +192,10 @@ static cl::opt ClOptSameTemp("asan-opt-same-temp", static cl::opt ClOptGlobals("asan-opt-globals", cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true)); +static cl::opt ClCheckLifetime("asan-check-lifetime", + cl::desc("Use llvm.lifetime intrinsics to insert extra checks"), + cl::Hidden, cl::init(false)); + // Debug flags. static cl::opt ClDebug("asan-debug", cl::desc("debug"), cl::Hidden, cl::init(0)); @@ -143,89 +208,381 @@ static cl::opt ClDebugMin("asan-debug-min", cl::desc("Debug min inst"), static cl::opt ClDebugMax("asan-debug-max", cl::desc("Debug man inst"), cl::Hidden, cl::init(-1)); -namespace { +STATISTIC(NumInstrumentedReads, "Number of instrumented reads"); +STATISTIC(NumInstrumentedWrites, "Number of instrumented writes"); +STATISTIC(NumOptimizedAccessesToGlobalArray, + "Number of optimized accesses to global arrays"); +STATISTIC(NumOptimizedAccessesToGlobalVar, + "Number of optimized accesses to global vars"); -/// When the crash callbacks are merged, they receive some amount of arguments -/// that are merged in a PHI node. This struct represents arguments from one -/// call site. -struct CrashArg { - Value *Arg1; - Value *Arg2; +namespace { +/// Frontend-provided metadata for source location. +struct LocationMetadata { + StringRef Filename; + int LineNo; + int ColumnNo; + + LocationMetadata() : Filename(), LineNo(0), ColumnNo(0) {} + + bool empty() const { return Filename.empty(); } + + void parse(MDNode *MDN) { + assert(MDN->getNumOperands() == 3); + MDString *MDFilename = cast(MDN->getOperand(0)); + Filename = MDFilename->getString(); + LineNo = cast(MDN->getOperand(1))->getLimitedValue(); + ColumnNo = cast(MDN->getOperand(2))->getLimitedValue(); + } }; -/// An object of this type is created while instrumenting every function. -struct AsanFunctionContext { - AsanFunctionContext(Function &Function) : F(Function), CrashBlock() { } +/// Frontend-provided metadata for global variables. +class GlobalsMetadata { + public: + struct Entry { + Entry() + : SourceLoc(), Name(), IsDynInit(false), + IsBlacklisted(false) {} + LocationMetadata SourceLoc; + StringRef Name; + bool IsDynInit; + bool IsBlacklisted; + }; + + GlobalsMetadata() : inited_(false) {} + + void init(Module& M) { + assert(!inited_); + inited_ = true; + NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals"); + if (!Globals) + return; + for (auto MDN : Globals->operands()) { + // Metadata node contains the global and the fields of "Entry". + assert(MDN->getNumOperands() == 5); + Value *V = MDN->getOperand(0); + // The optimizer may optimize away a global entirely. + if (!V) + continue; + GlobalVariable *GV = cast(V); + // We can already have an entry for GV if it was merged with another + // global. + Entry &E = Entries[GV]; + if (Value *Loc = MDN->getOperand(1)) + E.SourceLoc.parse(cast(Loc)); + if (Value *Name = MDN->getOperand(2)) { + MDString *MDName = cast(Name); + E.Name = MDName->getString(); + } + ConstantInt *IsDynInit = cast(MDN->getOperand(3)); + E.IsDynInit |= IsDynInit->isOne(); + ConstantInt *IsBlacklisted = cast(MDN->getOperand(4)); + E.IsBlacklisted |= IsBlacklisted->isOne(); + } + } - Function &F; - // These are initially zero. If we require at least one call to - // __asan_report_{read,write}{1,2,4,8,16}, an appropriate BB is created. - BasicBlock *CrashBlock[2][kNumberOfAccessSizes]; - typedef SmallVector CrashArgsVec; - CrashArgsVec CrashArgs[2][kNumberOfAccessSizes]; + /// Returns metadata entry for a given global. + Entry get(GlobalVariable *G) const { + auto Pos = Entries.find(G); + return (Pos != Entries.end()) ? Pos->second : Entry(); + } + + private: + bool inited_; + DenseMap Entries; +}; + +/// This struct defines the shadow mapping using the rule: +/// shadow = (mem >> Scale) ADD-or-OR Offset. +struct ShadowMapping { + int Scale; + uint64_t Offset; + bool OrShadowOffset; }; +static ShadowMapping getShadowMapping(const Module &M, int LongSize) { + llvm::Triple TargetTriple(M.getTargetTriple()); + bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android; + bool IsIOS = TargetTriple.isiOS(); + bool IsFreeBSD = TargetTriple.getOS() == llvm::Triple::FreeBSD; + bool IsLinux = TargetTriple.getOS() == llvm::Triple::Linux; + bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 || + TargetTriple.getArch() == llvm::Triple::ppc64le; + bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64; + bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips || + TargetTriple.getArch() == llvm::Triple::mipsel; + + ShadowMapping Mapping; + + if (LongSize == 32) { + if (IsAndroid) + Mapping.Offset = 0; + else if (IsMIPS32) + Mapping.Offset = kMIPS32_ShadowOffset32; + else if (IsFreeBSD) + Mapping.Offset = kFreeBSD_ShadowOffset32; + else if (IsIOS) + Mapping.Offset = kIOSShadowOffset32; + else + Mapping.Offset = kDefaultShadowOffset32; + } else { // LongSize == 64 + if (IsPPC64) + Mapping.Offset = kPPC64_ShadowOffset64; + else if (IsFreeBSD) + Mapping.Offset = kFreeBSD_ShadowOffset64; + else if (IsLinux && IsX86_64) + Mapping.Offset = kSmallX86_64ShadowOffset; + else + Mapping.Offset = kDefaultShadowOffset64; + } + + Mapping.Scale = kDefaultShadowScale; + if (ClMappingScale) { + Mapping.Scale = ClMappingScale; + } + + // OR-ing shadow offset if more efficient (at least on x86) if the offset + // is a power of two, but on ppc64 we have to use add since the shadow + // offset is not necessary 1/8-th of the address space. + Mapping.OrShadowOffset = !IsPPC64 && !(Mapping.Offset & (Mapping.Offset - 1)); + + return Mapping; +} + +static size_t RedzoneSizeForScale(int MappingScale) { + // Redzone used for stack and globals is at least 32 bytes. + // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively. + return std::max(32U, 1U << MappingScale); +} + /// AddressSanitizer: instrument the code in module to find memory bugs. -struct AddressSanitizer : public ModulePass { - AddressSanitizer(); - virtual const char *getPassName() const; - void instrumentMop(AsanFunctionContext &AFC, Instruction *I); - void instrumentAddress(AsanFunctionContext &AFC, - Instruction *OrigIns, IRBuilder<> &IRB, - Value *Addr, uint32_t TypeSize, bool IsWrite); +struct AddressSanitizer : public FunctionPass { + AddressSanitizer() : FunctionPass(ID) { + initializeBreakCriticalEdgesPass(*PassRegistry::getPassRegistry()); + } + const char *getPassName() const override { + return "AddressSanitizerFunctionPass"; + } + void instrumentMop(Instruction *I, bool UseCalls); + void instrumentPointerComparisonOrSubtraction(Instruction *I); + void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore, + Value *Addr, uint32_t TypeSize, bool IsWrite, + Value *SizeArgument, bool UseCalls); Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong, Value *ShadowValue, uint32_t TypeSize); - Instruction *generateCrashCode(BasicBlock *BB, Value *Addr, Value *PC, - bool IsWrite, size_t AccessSizeIndex); - bool instrumentMemIntrinsic(AsanFunctionContext &AFC, MemIntrinsic *MI); - void instrumentMemIntrinsicParam(AsanFunctionContext &AFC, - Instruction *OrigIns, Value *Addr, - Value *Size, - Instruction *InsertBefore, bool IsWrite); + Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr, + bool IsWrite, size_t AccessSizeIndex, + Value *SizeArgument); + void instrumentMemIntrinsic(MemIntrinsic *MI); Value *memToShadow(Value *Shadow, IRBuilder<> &IRB); - bool handleFunction(Module &M, Function &F); + bool runOnFunction(Function &F) override; bool maybeInsertAsanInitAtFunctionEntry(Function &F); - bool poisonStackInFunction(Module &M, Function &F); - virtual bool runOnModule(Module &M); - bool insertGlobalRedzones(Module &M); + bool doInitialization(Module &M) override; static char ID; // Pass identification, replacement for typeid - private: - - uint64_t getAllocaSizeInBytes(AllocaInst *AI) { - Type *Ty = AI->getAllocatedType(); - uint64_t SizeInBytes = TD->getTypeAllocSize(Ty); - return SizeInBytes; - } - uint64_t getAlignedSize(uint64_t SizeInBytes) { - return ((SizeInBytes + RedzoneSize - 1) - / RedzoneSize) * RedzoneSize; - } - uint64_t getAlignedAllocaSize(AllocaInst *AI) { - uint64_t SizeInBytes = getAllocaSizeInBytes(AI); - return getAlignedSize(SizeInBytes); + void getAnalysisUsage(AnalysisUsage &AU) const override { + if (ClCoverage >= 3) + AU.addRequiredID(BreakCriticalEdgesID); } - Function *checkInterfaceFunction(Constant *FuncOrBitcast); - void PoisonStack(const ArrayRef &AllocaVec, IRBuilder<> IRB, - Value *ShadowBase, bool DoPoison); + private: + void initializeCallbacks(Module &M); + bool LooksLikeCodeInBug11395(Instruction *I); + bool GlobalIsLinkerInitialized(GlobalVariable *G); + void InjectCoverageForIndirectCalls(Function &F, + ArrayRef IndirCalls); + bool InjectCoverage(Function &F, ArrayRef AllBlocks, + ArrayRef IndirCalls); + void InjectCoverageAtBlock(Function &F, BasicBlock &BB); LLVMContext *C; - TargetData *TD; - uint64_t MappingOffset; - int MappingScale; - size_t RedzoneSize; + const DataLayout *DL; int LongSize; Type *IntptrTy; - Type *IntptrPtrTy; + ShadowMapping Mapping; Function *AsanCtorFunction; Function *AsanInitFunction; - Instruction *CtorInsertBefore; - OwningPtr BL; + Function *AsanHandleNoReturnFunc; + Function *AsanCovFunction; + Function *AsanCovIndirCallFunction; + Function *AsanPtrCmpFunction, *AsanPtrSubFunction; // This array is indexed by AccessIsWrite and log2(AccessSize). Function *AsanErrorCallback[2][kNumberOfAccessSizes]; + Function *AsanMemoryAccessCallback[2][kNumberOfAccessSizes]; + // This array is indexed by AccessIsWrite. + Function *AsanErrorCallbackSized[2], + *AsanMemoryAccessCallbackSized[2]; + Function *AsanMemmove, *AsanMemcpy, *AsanMemset; InlineAsm *EmptyAsm; + GlobalsMetadata GlobalsMD; + + friend struct FunctionStackPoisoner; +}; + +class AddressSanitizerModule : public ModulePass { + public: + AddressSanitizerModule() : ModulePass(ID) {} + bool runOnModule(Module &M) override; + static char ID; // Pass identification, replacement for typeid + const char *getPassName() const override { + return "AddressSanitizerModule"; + } + + private: + void initializeCallbacks(Module &M); + + bool InstrumentGlobals(IRBuilder<> &IRB, Module &M); + bool ShouldInstrumentGlobal(GlobalVariable *G); + void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName); + void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName); + size_t MinRedzoneSizeForGlobal() const { + return RedzoneSizeForScale(Mapping.Scale); + } + + GlobalsMetadata GlobalsMD; + Type *IntptrTy; + LLVMContext *C; + const DataLayout *DL; + ShadowMapping Mapping; + Function *AsanPoisonGlobals; + Function *AsanUnpoisonGlobals; + Function *AsanRegisterGlobals; + Function *AsanUnregisterGlobals; + Function *AsanCovModuleInit; +}; + +// Stack poisoning does not play well with exception handling. +// When an exception is thrown, we essentially bypass the code +// that unpoisones the stack. This is why the run-time library has +// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire +// stack in the interceptor. This however does not work inside the +// actual function which catches the exception. Most likely because the +// compiler hoists the load of the shadow value somewhere too high. +// This causes asan to report a non-existing bug on 453.povray. +// It sounds like an LLVM bug. +struct FunctionStackPoisoner : public InstVisitor { + Function &F; + AddressSanitizer &ASan; + DIBuilder DIB; + LLVMContext *C; + Type *IntptrTy; + Type *IntptrPtrTy; + ShadowMapping Mapping; + + SmallVector AllocaVec; + SmallVector RetVec; + unsigned StackAlignment; + + Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1], + *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1]; + Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc; + + // Stores a place and arguments of poisoning/unpoisoning call for alloca. + struct AllocaPoisonCall { + IntrinsicInst *InsBefore; + AllocaInst *AI; + uint64_t Size; + bool DoPoison; + }; + SmallVector AllocaPoisonCallVec; + + // Maps Value to an AllocaInst from which the Value is originated. + typedef DenseMap AllocaForValueMapTy; + AllocaForValueMapTy AllocaForValue; + + FunctionStackPoisoner(Function &F, AddressSanitizer &ASan) + : F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C), + IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)), + Mapping(ASan.Mapping), + StackAlignment(1 << Mapping.Scale) {} + + bool runOnFunction() { + if (!ClStack) return false; + // Collect alloca, ret, lifetime instructions etc. + for (BasicBlock *BB : depth_first(&F.getEntryBlock())) + visit(*BB); + + if (AllocaVec.empty()) return false; + + initializeCallbacks(*F.getParent()); + + poisonStack(); + + if (ClDebugStack) { + DEBUG(dbgs() << F); + } + return true; + } + + // Finds all static Alloca instructions and puts + // poisoned red zones around all of them. + // Then unpoison everything back before the function returns. + void poisonStack(); + + // ----------------------- Visitors. + /// \brief Collect all Ret instructions. + void visitReturnInst(ReturnInst &RI) { + RetVec.push_back(&RI); + } + + /// \brief Collect Alloca instructions we want (and can) handle. + void visitAllocaInst(AllocaInst &AI) { + if (!isInterestingAlloca(AI)) return; + + StackAlignment = std::max(StackAlignment, AI.getAlignment()); + AllocaVec.push_back(&AI); + } + + /// \brief Collect lifetime intrinsic calls to check for use-after-scope + /// errors. + void visitIntrinsicInst(IntrinsicInst &II) { + if (!ClCheckLifetime) return; + Intrinsic::ID ID = II.getIntrinsicID(); + if (ID != Intrinsic::lifetime_start && + ID != Intrinsic::lifetime_end) + return; + // Found lifetime intrinsic, add ASan instrumentation if necessary. + ConstantInt *Size = dyn_cast(II.getArgOperand(0)); + // If size argument is undefined, don't do anything. + if (Size->isMinusOne()) return; + // Check that size doesn't saturate uint64_t and can + // be stored in IntptrTy. + const uint64_t SizeValue = Size->getValue().getLimitedValue(); + if (SizeValue == ~0ULL || + !ConstantInt::isValueValidForType(IntptrTy, SizeValue)) + return; + // Find alloca instruction that corresponds to llvm.lifetime argument. + AllocaInst *AI = findAllocaForValue(II.getArgOperand(1)); + if (!AI) return; + bool DoPoison = (ID == Intrinsic::lifetime_end); + AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison}; + AllocaPoisonCallVec.push_back(APC); + } + + // ---------------------- Helpers. + void initializeCallbacks(Module &M); + + // Check if we want (and can) handle this alloca. + bool isInterestingAlloca(AllocaInst &AI) const { + return (!AI.isArrayAllocation() && AI.isStaticAlloca() && + AI.getAllocatedType()->isSized() && + // alloca() may be called with 0 size, ignore it. + getAllocaSizeInBytes(&AI) > 0); + } + + uint64_t getAllocaSizeInBytes(AllocaInst *AI) const { + Type *Ty = AI->getAllocatedType(); + uint64_t SizeInBytes = ASan.DL->getTypeAllocSize(Ty); + return SizeInBytes; + } + /// Finds alloca where the value comes from. + AllocaInst *findAllocaForValue(Value *V); + void poisonRedZones(ArrayRef ShadowBytes, IRBuilder<> &IRB, + Value *ShadowBase, bool DoPoison); + void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison); + + void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase, + int Size); }; } // namespace @@ -234,172 +591,234 @@ char AddressSanitizer::ID = 0; INITIALIZE_PASS(AddressSanitizer, "asan", "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false, false) -AddressSanitizer::AddressSanitizer() : ModulePass(ID) { } -ModulePass *llvm::createAddressSanitizerPass() { +FunctionPass *llvm::createAddressSanitizerFunctionPass() { return new AddressSanitizer(); } -const char *AddressSanitizer::getPassName() const { - return "AddressSanitizer"; +char AddressSanitizerModule::ID = 0; +INITIALIZE_PASS(AddressSanitizerModule, "asan-module", + "AddressSanitizer: detects use-after-free and out-of-bounds bugs." + "ModulePass", false, false) +ModulePass *llvm::createAddressSanitizerModulePass() { + return new AddressSanitizerModule(); } static size_t TypeSizeToSizeIndex(uint32_t TypeSize) { - size_t Res = CountTrailingZeros_32(TypeSize / 8); + size_t Res = countTrailingZeros(TypeSize / 8); assert(Res < kNumberOfAccessSizes); return Res; } -// Create a constant for Str so that we can pass it to the run-time lib. -static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) { +// \brief Create a constant for Str so that we can pass it to the run-time lib. +static GlobalVariable *createPrivateGlobalForString( + Module &M, StringRef Str, bool AllowMerging) { Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str); - return new GlobalVariable(M, StrConst->getType(), true, - GlobalValue::PrivateLinkage, StrConst, ""); + // We use private linkage for module-local strings. If they can be merged + // with another one, we set the unnamed_addr attribute. + GlobalVariable *GV = + new GlobalVariable(M, StrConst->getType(), true, + GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix); + if (AllowMerging) + GV->setUnnamedAddr(true); + GV->setAlignment(1); // Strings may not be merged w/o setting align 1. + return GV; } -// Split the basic block and insert an if-then code. -// Before: -// Head -// Cmp -// Tail -// After: -// Head -// if (Cmp) -// ThenBlock -// Tail -// -// If ThenBlock is zero, a new block is created and its terminator is returned. -// Otherwize 0 is returned. -static BranchInst *splitBlockAndInsertIfThen(Value *Cmp, - BasicBlock *ThenBlock = 0) { - Instruction *SplitBefore = cast(Cmp)->getNextNode(); - BasicBlock *Head = SplitBefore->getParent(); - BasicBlock *Tail = Head->splitBasicBlock(SplitBefore); - TerminatorInst *HeadOldTerm = Head->getTerminator(); - BranchInst *CheckTerm = 0; - if (!ThenBlock) { - LLVMContext &C = Head->getParent()->getParent()->getContext(); - ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail); - CheckTerm = BranchInst::Create(Tail, ThenBlock); - } - BranchInst *HeadNewTerm = - BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp); - ReplaceInstWithInst(HeadOldTerm, HeadNewTerm); +/// \brief Create a global describing a source location. +static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M, + LocationMetadata MD) { + Constant *LocData[] = { + createPrivateGlobalForString(M, MD.Filename, true), + ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.LineNo), + ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.ColumnNo), + }; + auto LocStruct = ConstantStruct::getAnon(LocData); + auto GV = new GlobalVariable(M, LocStruct->getType(), true, + GlobalValue::PrivateLinkage, LocStruct, + kAsanGenPrefix); + GV->setUnnamedAddr(true); + return GV; +} - return CheckTerm; +static bool GlobalWasGeneratedByAsan(GlobalVariable *G) { + return G->getName().find(kAsanGenPrefix) == 0; } Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) { // Shadow >> scale - Shadow = IRB.CreateLShr(Shadow, MappingScale); - if (MappingOffset == 0) + Shadow = IRB.CreateLShr(Shadow, Mapping.Scale); + if (Mapping.Offset == 0) return Shadow; // (Shadow >> scale) | offset - return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, - MappingOffset)); -} - -void AddressSanitizer::instrumentMemIntrinsicParam( - AsanFunctionContext &AFC, Instruction *OrigIns, - Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) { - // Check the first byte. - { - IRBuilder<> IRB(InsertBefore); - instrumentAddress(AFC, OrigIns, IRB, Addr, 8, IsWrite); - } - // Check the last byte. - { - IRBuilder<> IRB(InsertBefore); - Value *SizeMinusOne = IRB.CreateSub( - Size, ConstantInt::get(Size->getType(), 1)); - SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false); - Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy); - Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne); - instrumentAddress(AFC, OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite); - } + if (Mapping.OrShadowOffset) + return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset)); + else + return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset)); } // Instrument memset/memmove/memcpy -bool AddressSanitizer::instrumentMemIntrinsic(AsanFunctionContext &AFC, - MemIntrinsic *MI) { - Value *Dst = MI->getDest(); - MemTransferInst *MemTran = dyn_cast(MI); - Value *Src = MemTran ? MemTran->getSource() : 0; - Value *Length = MI->getLength(); - - Constant *ConstLength = dyn_cast(Length); - Instruction *InsertBefore = MI; - if (ConstLength) { - if (ConstLength->isNullValue()) return false; - } else { - // The size is not a constant so it could be zero -- check at run-time. - IRBuilder<> IRB(InsertBefore); - - Value *Cmp = IRB.CreateICmpNE(Length, - Constant::getNullValue(Length->getType())); - InsertBefore = splitBlockAndInsertIfThen(Cmp); +void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) { + IRBuilder<> IRB(MI); + if (isa(MI)) { + IRB.CreateCall3( + isa(MI) ? AsanMemmove : AsanMemcpy, + IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()), + IRB.CreatePointerCast(MI->getOperand(1), IRB.getInt8PtrTy()), + IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)); + } else if (isa(MI)) { + IRB.CreateCall3( + AsanMemset, + IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()), + IRB.CreateIntCast(MI->getOperand(1), IRB.getInt32Ty(), false), + IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)); } - - instrumentMemIntrinsicParam(AFC, MI, Dst, Length, InsertBefore, true); - if (Src) - instrumentMemIntrinsicParam(AFC, MI, Src, Length, InsertBefore, false); - return true; + MI->eraseFromParent(); } // If I is an interesting memory access, return the PointerOperand -// and set IsWrite. Otherwise return NULL. -static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) { +// and set IsWrite/Alignment. Otherwise return NULL. +static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite, + unsigned *Alignment) { + // Skip memory accesses inserted by another instrumentation. + if (I->getMetadata("nosanitize")) + return nullptr; if (LoadInst *LI = dyn_cast(I)) { - if (!ClInstrumentReads) return NULL; + if (!ClInstrumentReads) return nullptr; *IsWrite = false; + *Alignment = LI->getAlignment(); return LI->getPointerOperand(); } if (StoreInst *SI = dyn_cast(I)) { - if (!ClInstrumentWrites) return NULL; + if (!ClInstrumentWrites) return nullptr; *IsWrite = true; + *Alignment = SI->getAlignment(); return SI->getPointerOperand(); } if (AtomicRMWInst *RMW = dyn_cast(I)) { - if (!ClInstrumentAtomics) return NULL; + if (!ClInstrumentAtomics) return nullptr; *IsWrite = true; + *Alignment = 0; return RMW->getPointerOperand(); } if (AtomicCmpXchgInst *XCHG = dyn_cast(I)) { - if (!ClInstrumentAtomics) return NULL; + if (!ClInstrumentAtomics) return nullptr; *IsWrite = true; + *Alignment = 0; return XCHG->getPointerOperand(); } - return NULL; + return nullptr; } -void AddressSanitizer::instrumentMop(AsanFunctionContext &AFC, Instruction *I) { - bool IsWrite; - Value *Addr = isInterestingMemoryAccess(I, &IsWrite); +static bool isPointerOperand(Value *V) { + return V->getType()->isPointerTy() || isa(V); +} + +// This is a rough heuristic; it may cause both false positives and +// false negatives. The proper implementation requires cooperation with +// the frontend. +static bool isInterestingPointerComparisonOrSubtraction(Instruction *I) { + if (ICmpInst *Cmp = dyn_cast(I)) { + if (!Cmp->isRelational()) + return false; + } else if (BinaryOperator *BO = dyn_cast(I)) { + if (BO->getOpcode() != Instruction::Sub) + return false; + } else { + return false; + } + if (!isPointerOperand(I->getOperand(0)) || + !isPointerOperand(I->getOperand(1))) + return false; + return true; +} + +bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) { + // If a global variable does not have dynamic initialization we don't + // have to instrument it. However, if a global does not have initializer + // at all, we assume it has dynamic initializer (in other TU). + return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit; +} + +void +AddressSanitizer::instrumentPointerComparisonOrSubtraction(Instruction *I) { + IRBuilder<> IRB(I); + Function *F = isa(I) ? AsanPtrCmpFunction : AsanPtrSubFunction; + Value *Param[2] = {I->getOperand(0), I->getOperand(1)}; + for (int i = 0; i < 2; i++) { + if (Param[i]->getType()->isPointerTy()) + Param[i] = IRB.CreatePointerCast(Param[i], IntptrTy); + } + IRB.CreateCall2(F, Param[0], Param[1]); +} + +void AddressSanitizer::instrumentMop(Instruction *I, bool UseCalls) { + bool IsWrite = false; + unsigned Alignment = 0; + Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &Alignment); assert(Addr); - if (ClOpt && ClOptGlobals && isa(Addr)) { - // We are accessing a global scalar variable. Nothing to catch here. - return; + if (ClOpt && ClOptGlobals) { + if (GlobalVariable *G = dyn_cast(Addr)) { + // If initialization order checking is disabled, a simple access to a + // dynamically initialized global is always valid. + if (!ClInitializers || GlobalIsLinkerInitialized(G)) { + NumOptimizedAccessesToGlobalVar++; + return; + } + } + ConstantExpr *CE = dyn_cast(Addr); + if (CE && CE->isGEPWithNoNotionalOverIndexing()) { + if (GlobalVariable *G = dyn_cast(CE->getOperand(0))) { + if (CE->getOperand(1)->isNullValue() && GlobalIsLinkerInitialized(G)) { + NumOptimizedAccessesToGlobalArray++; + return; + } + } + } } + Type *OrigPtrTy = Addr->getType(); Type *OrigTy = cast(OrigPtrTy)->getElementType(); assert(OrigTy->isSized()); - uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy); + uint32_t TypeSize = DL->getTypeStoreSizeInBits(OrigTy); - if (TypeSize != 8 && TypeSize != 16 && - TypeSize != 32 && TypeSize != 64 && TypeSize != 128) { - // Ignore all unusual sizes. - return; - } + assert((TypeSize % 8) == 0); + if (IsWrite) + NumInstrumentedWrites++; + else + NumInstrumentedReads++; + + unsigned Granularity = 1 << Mapping.Scale; + // Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check + // if the data is properly aligned. + if ((TypeSize == 8 || TypeSize == 16 || TypeSize == 32 || TypeSize == 64 || + TypeSize == 128) && + (Alignment >= Granularity || Alignment == 0 || Alignment >= TypeSize / 8)) + return instrumentAddress(I, I, Addr, TypeSize, IsWrite, nullptr, UseCalls); + // Instrument unusual size or unusual alignment. + // We can not do it with a single check, so we do 1-byte check for the first + // and the last bytes. We call __asan_report_*_n(addr, real_size) to be able + // to report the actual access size. IRBuilder<> IRB(I); - instrumentAddress(AFC, I, IRB, Addr, TypeSize, IsWrite); + Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8); + Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy); + if (UseCalls) { + IRB.CreateCall2(AsanMemoryAccessCallbackSized[IsWrite], AddrLong, Size); + } else { + Value *LastByte = IRB.CreateIntToPtr( + IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)), + OrigPtrTy); + instrumentAddress(I, I, Addr, 8, IsWrite, Size, false); + instrumentAddress(I, I, LastByte, 8, IsWrite, Size, false); + } } // Validate the result of Module::getOrInsertFunction called for an interface // function of AddressSanitizer. If the instrumented module defines a function // with the same name, their prototypes must match, otherwise // getOrInsertFunction returns a bitcast. -Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) { +static Function *checkInterfaceFunction(Constant *FuncOrBitcast) { if (isa(FuncOrBitcast)) return cast(FuncOrBitcast); FuncOrBitcast->dump(); report_fatal_error("trying to redefine an AddressSanitizer " @@ -407,15 +826,13 @@ Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) { } Instruction *AddressSanitizer::generateCrashCode( - BasicBlock *BB, Value *Addr, Value *PC, - bool IsWrite, size_t AccessSizeIndex) { - IRBuilder<> IRB(BB->getFirstNonPHI()); - CallInst *Call; - if (PC) - Call = IRB.CreateCall2(AsanErrorCallback[IsWrite][AccessSizeIndex], - Addr, PC); - else - Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr); + Instruction *InsertBefore, Value *Addr, + bool IsWrite, size_t AccessSizeIndex, Value *SizeArgument) { + IRBuilder<> IRB(InsertBefore); + CallInst *Call = SizeArgument + ? IRB.CreateCall2(AsanErrorCallbackSized[IsWrite], Addr, SizeArgument) + : IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr); + // We don't do Call->setDoesNotReturn() because the BB already has // UnreachableInst at the end. // This EmptyAsm is required to avoid callback merge. @@ -426,7 +843,7 @@ Instruction *AddressSanitizer::generateCrashCode( Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong, Value *ShadowValue, uint32_t TypeSize) { - size_t Granularity = 1 << MappingScale; + size_t Granularity = 1 << Mapping.Scale; // Addr & (Granularity - 1) Value *LastAccessedByte = IRB.CreateAnd( AddrLong, ConstantInt::get(IntptrTy, Granularity - 1)); @@ -436,19 +853,27 @@ Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong, LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)); // (uint8_t) ((Addr & (Granularity-1)) + size - 1) LastAccessedByte = IRB.CreateIntCast( - LastAccessedByte, IRB.getInt8Ty(), false); + LastAccessedByte, ShadowValue->getType(), false); // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue); } -void AddressSanitizer::instrumentAddress(AsanFunctionContext &AFC, - Instruction *OrigIns, - IRBuilder<> &IRB, Value *Addr, - uint32_t TypeSize, bool IsWrite) { +void AddressSanitizer::instrumentAddress(Instruction *OrigIns, + Instruction *InsertBefore, Value *Addr, + uint32_t TypeSize, bool IsWrite, + Value *SizeArgument, bool UseCalls) { + IRBuilder<> IRB(InsertBefore); Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy); + size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize); + + if (UseCalls) { + IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][AccessSizeIndex], + AddrLong); + return; + } Type *ShadowTy = IntegerType::get( - *C, std::max(8U, TypeSize >> MappingScale)); + *C, std::max(8U, TypeSize >> Mapping.Scale)); Type *ShadowPtrTy = PointerType::get(ShadowTy, 0); Value *ShadowPtr = memToShadow(AddrLong, IRB); Value *CmpVal = Constant::getNullValue(ShadowTy); @@ -456,112 +881,184 @@ void AddressSanitizer::instrumentAddress(AsanFunctionContext &AFC, IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy)); Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal); - - BasicBlock *CrashBlock = 0; - if (ClMergeCallbacks) { - size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize); - BasicBlock **Cached = &AFC.CrashBlock[IsWrite][AccessSizeIndex]; - if (!*Cached) { - std::string BBName("crash_bb-"); - BBName += (IsWrite ? "w-" : "r-") + itostr(1 << AccessSizeIndex); - BasicBlock *BB = BasicBlock::Create(*C, BBName, &AFC.F); - new UnreachableInst(*C, BB); - *Cached = BB; - } - CrashBlock = *Cached; - // We need to pass the PC as the second parameter to __asan_report_*. - // There are few problems: - // - Some architectures (e.g. x86_32) don't have a cheap way to get the PC. - // - LLVM doesn't have the appropriate intrinsic. - // For now, put a random number into the PC, just to allow experiments. - Value *PC = ConstantInt::get(IntptrTy, rand()); - CrashArg Arg = {AddrLong, PC}; - AFC.CrashArgs[IsWrite][AccessSizeIndex].push_back(Arg); - } else { - CrashBlock = BasicBlock::Create(*C, "crash_bb", &AFC.F); - new UnreachableInst(*C, CrashBlock); - size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize); - Instruction *Crash = - generateCrashCode(CrashBlock, AddrLong, 0, IsWrite, AccessSizeIndex); - Crash->setDebugLoc(OrigIns->getDebugLoc()); - } - - size_t Granularity = 1 << MappingScale; - if (TypeSize < 8 * Granularity) { - BranchInst *CheckTerm = splitBlockAndInsertIfThen(Cmp); - assert(CheckTerm->isUnconditional()); + size_t Granularity = 1 << Mapping.Scale; + TerminatorInst *CrashTerm = nullptr; + + if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) { + // We use branch weights for the slow path check, to indicate that the slow + // path is rarely taken. This seems to be the case for SPEC benchmarks. + TerminatorInst *CheckTerm = + SplitBlockAndInsertIfThen(Cmp, InsertBefore, false, + MDBuilder(*C).createBranchWeights(1, 100000)); + assert(dyn_cast(CheckTerm)->isUnconditional()); BasicBlock *NextBB = CheckTerm->getSuccessor(0); IRB.SetInsertPoint(CheckTerm); Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize); + BasicBlock *CrashBlock = + BasicBlock::Create(*C, "", NextBB->getParent(), NextBB); + CrashTerm = new UnreachableInst(*C, CrashBlock); BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2); ReplaceInstWithInst(CheckTerm, NewTerm); } else { - splitBlockAndInsertIfThen(Cmp, CrashBlock); + CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, true); } + + Instruction *Crash = generateCrashCode( + CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument); + Crash->setDebugLoc(OrigIns->getDebugLoc()); } -// This function replaces all global variables with new variables that have -// trailing redzones. It also creates a function that poisons -// redzones and inserts this function into llvm.global_ctors. -bool AddressSanitizer::insertGlobalRedzones(Module &M) { - SmallVector GlobalsToChange; +void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit, + GlobalValue *ModuleName) { + // Set up the arguments to our poison/unpoison functions. + IRBuilder<> IRB(GlobalInit.begin()->getFirstInsertionPt()); - for (Module::GlobalListType::iterator G = M.getGlobalList().begin(), - E = M.getGlobalList().end(); G != E; ++G) { - Type *Ty = cast(G->getType())->getElementType(); - DEBUG(dbgs() << "GLOBAL: " << *G); - - if (!Ty->isSized()) continue; - if (!G->hasInitializer()) continue; - // Touch only those globals that will not be defined in other modules. - // Don't handle ODR type linkages since other modules may be built w/o asan. - if (G->getLinkage() != GlobalVariable::ExternalLinkage && - G->getLinkage() != GlobalVariable::PrivateLinkage && - G->getLinkage() != GlobalVariable::InternalLinkage) - continue; - // Two problems with thread-locals: - // - The address of the main thread's copy can't be computed at link-time. - // - Need to poison all copies, not just the main thread's one. - if (G->isThreadLocal()) - continue; - // For now, just ignore this Alloca if the alignment is large. - if (G->getAlignment() > RedzoneSize) continue; - - // Ignore all the globals with the names starting with "\01L_OBJC_". - // Many of those are put into the .cstring section. The linker compresses - // that section by removing the spare \0s after the string terminator, so - // our redzones get broken. - if ((G->getName().find("\01L_OBJC_") == 0) || - (G->getName().find("\01l_OBJC_") == 0)) { - DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G); + // Add a call to poison all external globals before the given function starts. + Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy); + IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr); + + // Add calls to unpoison all globals before each return instruction. + for (auto &BB : GlobalInit.getBasicBlockList()) + if (ReturnInst *RI = dyn_cast(BB.getTerminator())) + CallInst::Create(AsanUnpoisonGlobals, "", RI); +} + +void AddressSanitizerModule::createInitializerPoisonCalls( + Module &M, GlobalValue *ModuleName) { + GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors"); + + ConstantArray *CA = cast(GV->getInitializer()); + for (Use &OP : CA->operands()) { + if (isa(OP)) continue; + ConstantStruct *CS = cast(OP); + + // Must have a function or null ptr. + if (Function* F = dyn_cast(CS->getOperand(1))) { + if (F->getName() == kAsanModuleCtorName) continue; + ConstantInt *Priority = dyn_cast(CS->getOperand(0)); + // Don't instrument CTORs that will run before asan.module_ctor. + if (Priority->getLimitedValue() <= kAsanCtorAndDtorPriority) continue; + poisonOneInitializer(*F, ModuleName); } + } +} - if (G->hasSection()) { - StringRef Section(G->getSection()); - // Ignore the globals from the __OBJC section. The ObjC runtime assumes - // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to - // them. - if ((Section.find("__OBJC,") == 0) || - (Section.find("__DATA, __objc_") == 0)) { - DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G); - continue; - } - // See http://code.google.com/p/address-sanitizer/issues/detail?id=32 - // Constant CFString instances are compiled in the following way: - // -- the string buffer is emitted into - // __TEXT,__cstring,cstring_literals - // -- the constant NSConstantString structure referencing that buffer - // is placed into __DATA,__cfstring - // Therefore there's no point in placing redzones into __DATA,__cfstring. - // Moreover, it causes the linker to crash on OS X 10.7 - if (Section.find("__DATA,__cfstring") == 0) { - DEBUG(dbgs() << "Ignoring CFString: " << *G); - continue; - } +bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) { + Type *Ty = cast(G->getType())->getElementType(); + DEBUG(dbgs() << "GLOBAL: " << *G << "\n"); + + if (GlobalsMD.get(G).IsBlacklisted) return false; + if (!Ty->isSized()) return false; + if (!G->hasInitializer()) return false; + if (GlobalWasGeneratedByAsan(G)) return false; // Our own global. + // Touch only those globals that will not be defined in other modules. + // Don't handle ODR linkage types and COMDATs since other modules may be built + // without ASan. + if (G->getLinkage() != GlobalVariable::ExternalLinkage && + G->getLinkage() != GlobalVariable::PrivateLinkage && + G->getLinkage() != GlobalVariable::InternalLinkage) + return false; + if (G->hasComdat()) + return false; + // Two problems with thread-locals: + // - The address of the main thread's copy can't be computed at link-time. + // - Need to poison all copies, not just the main thread's one. + if (G->isThreadLocal()) + return false; + // For now, just ignore this Global if the alignment is large. + if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false; + + // Ignore all the globals with the names starting with "\01L_OBJC_". + // Many of those are put into the .cstring section. The linker compresses + // that section by removing the spare \0s after the string terminator, so + // our redzones get broken. + if ((G->getName().find("\01L_OBJC_") == 0) || + (G->getName().find("\01l_OBJC_") == 0)) { + DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G << "\n"); + return false; + } + + if (G->hasSection()) { + StringRef Section(G->getSection()); + // Ignore the globals from the __OBJC section. The ObjC runtime assumes + // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to + // them. + if (Section.startswith("__OBJC,") || + Section.startswith("__DATA, __objc_")) { + DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n"); + return false; + } + // See http://code.google.com/p/address-sanitizer/issues/detail?id=32 + // Constant CFString instances are compiled in the following way: + // -- the string buffer is emitted into + // __TEXT,__cstring,cstring_literals + // -- the constant NSConstantString structure referencing that buffer + // is placed into __DATA,__cfstring + // Therefore there's no point in placing redzones into __DATA,__cfstring. + // Moreover, it causes the linker to crash on OS X 10.7 + if (Section.startswith("__DATA,__cfstring")) { + DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n"); + return false; + } + // The linker merges the contents of cstring_literals and removes the + // trailing zeroes. + if (Section.startswith("__TEXT,__cstring,cstring_literals")) { + DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n"); + return false; + } + + // Callbacks put into the CRT initializer/terminator sections + // should not be instrumented. + // See https://code.google.com/p/address-sanitizer/issues/detail?id=305 + // and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx + if (Section.startswith(".CRT")) { + DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n"); + return false; } - GlobalsToChange.push_back(G); + // Globals from llvm.metadata aren't emitted, do not instrument them. + if (Section == "llvm.metadata") return false; + } + + return true; +} + +void AddressSanitizerModule::initializeCallbacks(Module &M) { + IRBuilder<> IRB(*C); + // Declare our poisoning and unpoisoning functions. + AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction( + kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL)); + AsanPoisonGlobals->setLinkage(Function::ExternalLinkage); + AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction( + kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL)); + AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage); + // Declare functions that register/unregister globals. + AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction( + kAsanRegisterGlobalsName, IRB.getVoidTy(), + IntptrTy, IntptrTy, NULL)); + AsanRegisterGlobals->setLinkage(Function::ExternalLinkage); + AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction( + kAsanUnregisterGlobalsName, + IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage); + AsanCovModuleInit = checkInterfaceFunction(M.getOrInsertFunction( + kAsanCovModuleInitName, + IRB.getVoidTy(), IntptrTy, NULL)); + AsanCovModuleInit->setLinkage(Function::ExternalLinkage); +} + +// This function replaces all global variables with new variables that have +// trailing redzones. It also creates a function that poisons +// redzones and inserts this function into llvm.global_ctors. +bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) { + GlobalsMD.init(M); + + SmallVector GlobalsToChange; + + for (auto &G : M.globals()) { + if (ShouldInstrumentGlobal(&G)) + GlobalsToChange.push_back(&G); } size_t n = GlobalsToChange.size(); @@ -572,20 +1069,47 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) { // size_t size; // size_t size_with_redzone; // const char *name; + // const char *module_name; + // size_t has_dynamic_init; + // void *source_location; // We initialize an array of such structures and pass it to a run-time call. - StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy, - IntptrTy, IntptrTy, NULL); + StructType *GlobalStructTy = + StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy, + IntptrTy, IntptrTy, NULL); SmallVector Initializers(n); - IRBuilder<> IRB(CtorInsertBefore); + bool HasDynamicallyInitializedGlobals = false; + + // We shouldn't merge same module names, as this string serves as unique + // module ID in runtime. + GlobalVariable *ModuleName = createPrivateGlobalForString( + M, M.getModuleIdentifier(), /*AllowMerging*/false); for (size_t i = 0; i < n; i++) { + static const uint64_t kMaxGlobalRedzone = 1 << 18; GlobalVariable *G = GlobalsToChange[i]; + + auto MD = GlobalsMD.get(G); + // Create string holding the global name (use global name from metadata + // if it's available, otherwise just write the name of global variable). + GlobalVariable *Name = createPrivateGlobalForString( + M, MD.Name.empty() ? G->getName() : MD.Name, + /*AllowMerging*/ true); + PointerType *PtrTy = cast(G->getType()); Type *Ty = PtrTy->getElementType(); - uint64_t SizeInBytes = TD->getTypeAllocSize(Ty); - uint64_t RightRedzoneSize = RedzoneSize + - (RedzoneSize - (SizeInBytes % RedzoneSize)); + uint64_t SizeInBytes = DL->getTypeAllocSize(Ty); + uint64_t MinRZ = MinRedzoneSizeForGlobal(); + // MinRZ <= RZ <= kMaxGlobalRedzone + // and trying to make RZ to be ~ 1/4 of SizeInBytes. + uint64_t RZ = std::max(MinRZ, + std::min(kMaxGlobalRedzone, + (SizeInBytes / MinRZ / 4) * MinRZ)); + uint64_t RightRedzoneSize = RZ; + // Round up to MinRZ + if (SizeInBytes % MinRZ) + RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ); + assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0); Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize); StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL); @@ -593,18 +1117,15 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) { NewTy, G->getInitializer(), Constant::getNullValue(RightRedZoneTy), NULL); - SmallString<2048> DescriptionOfGlobal = G->getName(); - DescriptionOfGlobal += " ("; - DescriptionOfGlobal += M.getModuleIdentifier(); - DescriptionOfGlobal += ")"; - GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal); - // Create a new global variable with enough space for a redzone. + GlobalValue::LinkageTypes Linkage = G->getLinkage(); + if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage) + Linkage = GlobalValue::InternalLinkage; GlobalVariable *NewGlobal = new GlobalVariable( - M, NewTy, G->isConstant(), G->getLinkage(), + M, NewTy, G->isConstant(), Linkage, NewInitializer, "", G, G->getThreadLocalMode()); NewGlobal->copyAttributesFrom(G); - NewGlobal->setAlignment(RedzoneSize); + NewGlobal->setAlignment(MinRZ); Value *Indices2[2]; Indices2[0] = IRB.getInt32(0); @@ -615,25 +1136,36 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) { NewGlobal->takeName(G); G->eraseFromParent(); + Constant *SourceLoc; + if (!MD.SourceLoc.empty()) { + auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc); + SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy); + } else { + SourceLoc = ConstantInt::get(IntptrTy, 0); + } + Initializers[i] = ConstantStruct::get( - GlobalStructTy, - ConstantExpr::getPointerCast(NewGlobal, IntptrTy), + GlobalStructTy, ConstantExpr::getPointerCast(NewGlobal, IntptrTy), ConstantInt::get(IntptrTy, SizeInBytes), ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize), ConstantExpr::getPointerCast(Name, IntptrTy), - NULL); - DEBUG(dbgs() << "NEW GLOBAL:\n" << *NewGlobal); + ConstantExpr::getPointerCast(ModuleName, IntptrTy), + ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, NULL); + + if (ClInitializers && MD.IsDynInit) + HasDynamicallyInitializedGlobals = true; + + DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n"); } ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n); GlobalVariable *AllGlobals = new GlobalVariable( - M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage, + M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage, ConstantArray::get(ArrayOfGlobalStructTy, Initializers), ""); - Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction( - kAsanRegisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); - AsanRegisterGlobals->setLinkage(Function::ExternalLinkage); - + // Create calls for poisoning before initializers run and unpoisoning after. + if (HasDynamicallyInitializedGlobals) + createInitializerPoisonCalls(M, ModuleName); IRB.CreateCall2(AsanRegisterGlobals, IRB.CreatePointerCast(AllGlobals, IntptrTy), ConstantInt::get(IntptrTy, n)); @@ -645,122 +1177,132 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) { GlobalValue::InternalLinkage, kAsanModuleDtorName, &M); BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction); IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB)); - Function *AsanUnregisterGlobals = - checkInterfaceFunction(M.getOrInsertFunction( - kAsanUnregisterGlobalsName, - IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); - AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage); - IRB_Dtor.CreateCall2(AsanUnregisterGlobals, IRB.CreatePointerCast(AllGlobals, IntptrTy), ConstantInt::get(IntptrTy, n)); - appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority); + appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority); DEBUG(dbgs() << M); return true; } -// virtual -bool AddressSanitizer::runOnModule(Module &M) { - // Initialize the private fields. No one has accessed them before. - TD = getAnalysisIfAvailable(); - if (!TD) +bool AddressSanitizerModule::runOnModule(Module &M) { + DataLayoutPass *DLP = getAnalysisIfAvailable(); + if (!DLP) return false; - BL.reset(new FunctionBlackList(ClBlackListFile)); - + DL = &DLP->getDataLayout(); C = &(M.getContext()); - LongSize = TD->getPointerSizeInBits(); + int LongSize = DL->getPointerSizeInBits(); IntptrTy = Type::getIntNTy(*C, LongSize); - IntptrPtrTy = PointerType::get(IntptrTy, 0); + Mapping = getShadowMapping(M, LongSize); + initializeCallbacks(M); - AsanCtorFunction = Function::Create( - FunctionType::get(Type::getVoidTy(*C), false), - GlobalValue::InternalLinkage, kAsanModuleCtorName, &M); - BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction); - CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB); + bool Changed = false; - // call __asan_init in the module ctor. - IRBuilder<> IRB(CtorInsertBefore); - AsanInitFunction = checkInterfaceFunction( - M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL)); - AsanInitFunction->setLinkage(Function::ExternalLinkage); - IRB.CreateCall(AsanInitFunction); + Function *CtorFunc = M.getFunction(kAsanModuleCtorName); + assert(CtorFunc); + IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator()); + if (ClCoverage > 0) { + Function *CovFunc = M.getFunction(kAsanCovName); + int nCov = CovFunc ? CovFunc->getNumUses() : 0; + IRB.CreateCall(AsanCovModuleInit, ConstantInt::get(IntptrTy, nCov)); + Changed = true; + } + + if (ClGlobals) + Changed |= InstrumentGlobals(IRB, M); + + return Changed; +} + +void AddressSanitizer::initializeCallbacks(Module &M) { + IRBuilder<> IRB(*C); // Create __asan_report* callbacks. for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) { for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes; AccessSizeIndex++) { // IsWrite and TypeSize are encoded in the function name. - std::string FunctionName = std::string(kAsanReportErrorTemplate) + + std::string Suffix = (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex); - // If we are merging crash callbacks, they have two parameters. - if (ClMergeCallbacks) - AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast( - M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, - IntptrTy, NULL)); - else - AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast( - M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL)); + AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = + checkInterfaceFunction( + M.getOrInsertFunction(kAsanReportErrorTemplate + Suffix, + IRB.getVoidTy(), IntptrTy, NULL)); + AsanMemoryAccessCallback[AccessIsWrite][AccessSizeIndex] = + checkInterfaceFunction( + M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + Suffix, + IRB.getVoidTy(), IntptrTy, NULL)); } } + AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction( + kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction( + kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + + AsanMemoryAccessCallbackSized[0] = checkInterfaceFunction( + M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "loadN", + IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + AsanMemoryAccessCallbackSized[1] = checkInterfaceFunction( + M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "storeN", + IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + + AsanMemmove = checkInterfaceFunction(M.getOrInsertFunction( + ClMemoryAccessCallbackPrefix + "memmove", IRB.getInt8PtrTy(), + IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL)); + AsanMemcpy = checkInterfaceFunction(M.getOrInsertFunction( + ClMemoryAccessCallbackPrefix + "memcpy", IRB.getInt8PtrTy(), + IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, NULL)); + AsanMemset = checkInterfaceFunction(M.getOrInsertFunction( + ClMemoryAccessCallbackPrefix + "memset", IRB.getInt8PtrTy(), + IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, NULL)); + + AsanHandleNoReturnFunc = checkInterfaceFunction( + M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), NULL)); + AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction( + kAsanCovName, IRB.getVoidTy(), NULL)); + AsanCovIndirCallFunction = checkInterfaceFunction(M.getOrInsertFunction( + kAsanCovIndirCallName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + + AsanPtrCmpFunction = checkInterfaceFunction(M.getOrInsertFunction( + kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + AsanPtrSubFunction = checkInterfaceFunction(M.getOrInsertFunction( + kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); // We insert an empty inline asm after __asan_report* to avoid callback merge. EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false), StringRef(""), StringRef(""), /*hasSideEffects=*/true); +} - llvm::Triple targetTriple(M.getTargetTriple()); - bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::ANDROIDEABI; - - MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid : - (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64); - if (ClMappingOffsetLog >= 0) { - if (ClMappingOffsetLog == 0) { - // special case - MappingOffset = 0; - } else { - MappingOffset = 1ULL << ClMappingOffsetLog; - } - } - MappingScale = kDefaultShadowScale; - if (ClMappingScale) { - MappingScale = ClMappingScale; - } - // Redzone used for stack and globals is at least 32 bytes. - // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively. - RedzoneSize = std::max(32, (int)(1 << MappingScale)); - - bool Res = false; +// virtual +bool AddressSanitizer::doInitialization(Module &M) { + // Initialize the private fields. No one has accessed them before. + DataLayoutPass *DLP = getAnalysisIfAvailable(); + if (!DLP) + report_fatal_error("data layout missing"); + DL = &DLP->getDataLayout(); - if (ClGlobals) - Res |= insertGlobalRedzones(M); - - if (ClMappingOffsetLog >= 0) { - // Tell the run-time the current values of mapping offset and scale. - GlobalValue *asan_mapping_offset = - new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage, - ConstantInt::get(IntptrTy, MappingOffset), - kAsanMappingOffsetName); - // Read the global, otherwise it may be optimized away. - IRB.CreateLoad(asan_mapping_offset, true); - } - if (ClMappingScale) { - GlobalValue *asan_mapping_scale = - new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage, - ConstantInt::get(IntptrTy, MappingScale), - kAsanMappingScaleName); - // Read the global, otherwise it may be optimized away. - IRB.CreateLoad(asan_mapping_scale, true); - } + GlobalsMD.init(M); + C = &(M.getContext()); + LongSize = DL->getPointerSizeInBits(); + IntptrTy = Type::getIntNTy(*C, LongSize); - for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) { - if (F->isDeclaration()) continue; - Res |= handleFunction(M, *F); - } + AsanCtorFunction = Function::Create( + FunctionType::get(Type::getVoidTy(*C), false), + GlobalValue::InternalLinkage, kAsanModuleCtorName, &M); + BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction); + // call __asan_init in the module ctor. + IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB)); + AsanInitFunction = checkInterfaceFunction( + M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL)); + AsanInitFunction->setLinkage(Function::ExternalLinkage); + IRB.CreateCall(AsanInitFunction); - appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority); + Mapping = getShadowMapping(M, LongSize); - return Res; + appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority); + return true; } bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) { @@ -779,196 +1321,236 @@ bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) { return false; } -bool AddressSanitizer::handleFunction(Module &M, Function &F) { - if (BL->isIn(F)) return false; +void AddressSanitizer::InjectCoverageAtBlock(Function &F, BasicBlock &BB) { + BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end(); + // Skip static allocas at the top of the entry block so they don't become + // dynamic when we split the block. If we used our optimized stack layout, + // then there will only be one alloca and it will come first. + for (; IP != BE; ++IP) { + AllocaInst *AI = dyn_cast(IP); + if (!AI || !AI->isStaticAlloca()) + break; + } + + DebugLoc EntryLoc = &BB == &F.getEntryBlock() + ? IP->getDebugLoc().getFnDebugLoc(*C) + : IP->getDebugLoc(); + IRBuilder<> IRB(IP); + IRB.SetCurrentDebugLocation(EntryLoc); + Type *Int8Ty = IRB.getInt8Ty(); + GlobalVariable *Guard = new GlobalVariable( + *F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage, + Constant::getNullValue(Int8Ty), "__asan_gen_cov_" + F.getName()); + LoadInst *Load = IRB.CreateLoad(Guard); + Load->setAtomic(Monotonic); + Load->setAlignment(1); + Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), 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(AsanCovFunction); + StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard); + Store->setAtomic(Monotonic); + Store->setAlignment(1); +} + +// Poor man's coverage that works with ASan. +// We create a Guard boolean variable with the same linkage +// as the function and inject this code into the entry block (-asan-coverage=1) +// or all blocks (-asan-coverage=2): +// if (*Guard) { +// __sanitizer_cov(); +// *Guard = 1; +// } +// The accesses to Guard are atomic. The rest of the logic is +// in __sanitizer_cov (it's fine to call it more than once). +// +// This coverage implementation provides very limited data: +// it only tells if a given function (block) was ever executed. +// No counters, no per-edge data. +// But for many use cases this is what we need and the added slowdown +// is negligible. This simple implementation will probably be obsoleted +// by the upcoming Clang-based coverage implementation. +// By having it here and now we hope to +// a) get the functionality to users earlier and +// b) collect usage statistics to help improve Clang coverage design. +bool AddressSanitizer::InjectCoverage(Function &F, + ArrayRef AllBlocks, + ArrayRef IndirCalls) { + if (!ClCoverage) return false; + + if (ClCoverage == 1 || + (unsigned)ClCoverageBlockThreshold < AllBlocks.size()) { + InjectCoverageAtBlock(F, F.getEntryBlock()); + } else { + for (auto BB : AllBlocks) + InjectCoverageAtBlock(F, *BB); + } + InjectCoverageForIndirectCalls(F, IndirCalls); + 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 kCacheSize pointers (zero-initialed). +// The cache is used to speed up recording the caller-callee pairs. +// The address of the caller is passed implicitly via caller PC. +// kCacheSize is encoded in the name of the run-time function. +void AddressSanitizer::InjectCoverageForIndirectCalls( + Function &F, ArrayRef IndirCalls) { + if (ClCoverage < 4 || IndirCalls.empty()) return; + const int kCacheSize = 16; + const int kCacheAlignment = 64; // Align for better performance. + Type *Ty = ArrayType::get(IntptrTy, kCacheSize); + GlobalVariable *CalleeCache = + new GlobalVariable(*F.getParent(), Ty, false, GlobalValue::PrivateLinkage, + Constant::getNullValue(Ty), "__asan_gen_callee_cache"); + CalleeCache->setAlignment(kCacheAlignment); + for (auto I : IndirCalls) { + IRBuilder<> IRB(I); + CallSite CS(I); + IRB.CreateCall2(AsanCovIndirCallFunction, + IRB.CreatePointerCast(CS.getCalledValue(), IntptrTy), + IRB.CreatePointerCast(CalleeCache, IntptrTy)); + } +} + +bool AddressSanitizer::runOnFunction(Function &F) { if (&F == AsanCtorFunction) return false; + if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false; + DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n"); + initializeCallbacks(*F.getParent()); - // If needed, insert __asan_init before checking for AddressSafety attr. + // If needed, insert __asan_init before checking for SanitizeAddress attr. maybeInsertAsanInitAtFunctionEntry(F); - if (!F.hasFnAttr(Attribute::AddressSafety)) return false; + if (!F.hasFnAttribute(Attribute::SanitizeAddress)) + return false; if (!ClDebugFunc.empty() && ClDebugFunc != F.getName()) return false; - // We want to instrument every address only once per basic block - // (unless there are calls between uses). + + // We want to instrument every address only once per basic block (unless there + // are calls between uses). SmallSet TempsToInstrument; SmallVector ToInstrument; SmallVector NoReturnCalls; + SmallVector AllBlocks; + SmallVector PointerComparisonsOrSubtracts; + SmallVector IndirCalls; + int NumAllocas = 0; bool IsWrite; + unsigned Alignment; // Fill the set of memory operations to instrument. - for (Function::iterator FI = F.begin(), FE = F.end(); - FI != FE; ++FI) { + for (auto &BB : F) { + AllBlocks.push_back(&BB); TempsToInstrument.clear(); int NumInsnsPerBB = 0; - for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); - BI != BE; ++BI) { - if (LooksLikeCodeInBug11395(BI)) return false; - if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) { + for (auto &Inst : BB) { + if (LooksLikeCodeInBug11395(&Inst)) return false; + if (Value *Addr = + isInterestingMemoryAccess(&Inst, &IsWrite, &Alignment)) { if (ClOpt && ClOptSameTemp) { if (!TempsToInstrument.insert(Addr)) continue; // We've seen this temp in the current BB. } - } else if (isa(BI) && ClMemIntrin) { + } else if (ClInvalidPointerPairs && + isInterestingPointerComparisonOrSubtraction(&Inst)) { + PointerComparisonsOrSubtracts.push_back(&Inst); + continue; + } else if (isa(Inst)) { // ok, take it. } else { - if (CallInst *CI = dyn_cast(BI)) { + if (isa(Inst)) + NumAllocas++; + CallSite CS(&Inst); + if (CS) { // A call inside BB. TempsToInstrument.clear(); - if (CI->doesNotReturn()) { - NoReturnCalls.push_back(CI); - } + if (CS.doesNotReturn()) + NoReturnCalls.push_back(CS.getInstruction()); + if (ClCoverage >= 4 && !CS.getCalledFunction()) + IndirCalls.push_back(&Inst); } continue; } - ToInstrument.push_back(BI); + ToInstrument.push_back(&Inst); NumInsnsPerBB++; if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) break; } } - AsanFunctionContext AFC(F); + Function *UninstrumentedDuplicate = nullptr; + bool LikelyToInstrument = + !NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0); + if (ClKeepUninstrumented && LikelyToInstrument) { + ValueToValueMapTy VMap; + UninstrumentedDuplicate = CloneFunction(&F, VMap, false); + UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress); + UninstrumentedDuplicate->setName("NOASAN_" + F.getName()); + F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate); + } + + bool UseCalls = false; + if (ClInstrumentationWithCallsThreshold >= 0 && + ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold) + UseCalls = true; // Instrument. int NumInstrumented = 0; - for (size_t i = 0, n = ToInstrument.size(); i != n; i++) { - Instruction *Inst = ToInstrument[i]; + for (auto Inst : ToInstrument) { if (ClDebugMin < 0 || ClDebugMax < 0 || (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) { - if (isInterestingMemoryAccess(Inst, &IsWrite)) - instrumentMop(AFC, Inst); + if (isInterestingMemoryAccess(Inst, &IsWrite, &Alignment)) + instrumentMop(Inst, UseCalls); else - instrumentMemIntrinsic(AFC, cast(Inst)); + instrumentMemIntrinsic(cast(Inst)); } NumInstrumented++; } - // Create PHI nodes and crash callbacks if we are merging crash callbacks. - if (NumInstrumented) { - for (size_t IsWrite = 0; IsWrite <= 1; IsWrite++) { - for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes; - AccessSizeIndex++) { - BasicBlock *BB = AFC.CrashBlock[IsWrite][AccessSizeIndex]; - if (!BB) continue; - assert(ClMergeCallbacks); - AsanFunctionContext::CrashArgsVec &Args = - AFC.CrashArgs[IsWrite][AccessSizeIndex]; - IRBuilder<> IRB(BB->getFirstNonPHI()); - size_t n = Args.size(); - PHINode *PN1 = IRB.CreatePHI(IntptrTy, n); - PHINode *PN2 = IRB.CreatePHI(IntptrTy, n); - // We need to match crash parameters and the predecessors. - for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); - PI != PE; ++PI) { - n--; - PN1->addIncoming(Args[n].Arg1, *PI); - PN2->addIncoming(Args[n].Arg2, *PI); - } - assert(n == 0); - generateCrashCode(BB, PN1, PN2, IsWrite, AccessSizeIndex); - } - } - } - - DEBUG(dbgs() << F); - - bool ChangedStack = poisonStackInFunction(M, F); + FunctionStackPoisoner FSP(F, *this); + bool ChangedStack = FSP.runOnFunction(); // We must unpoison the stack before every NoReturn call (throw, _exit, etc). // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37 - for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) { - Instruction *CI = NoReturnCalls[i]; + for (auto CI : NoReturnCalls) { IRBuilder<> IRB(CI); - IRB.CreateCall(M.getOrInsertFunction(kAsanHandleNoReturnName, - IRB.getVoidTy(), NULL)); + IRB.CreateCall(AsanHandleNoReturnFunc); } - return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty(); -} + for (auto Inst : PointerComparisonsOrSubtracts) { + instrumentPointerComparisonOrSubtraction(Inst); + NumInstrumented++; + } -static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) { - if (ShadowRedzoneSize == 1) return PoisonByte; - if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte; - if (ShadowRedzoneSize == 4) - return (PoisonByte << 24) + (PoisonByte << 16) + - (PoisonByte << 8) + (PoisonByte); - llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4"); -} + bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty(); + + if (InjectCoverage(F, AllBlocks, IndirCalls)) + res = true; -static void PoisonShadowPartialRightRedzone(uint8_t *Shadow, - size_t Size, - size_t RedzoneSize, - size_t ShadowGranularity, - uint8_t Magic) { - for (size_t i = 0; i < RedzoneSize; - i+= ShadowGranularity, Shadow++) { - if (i + ShadowGranularity <= Size) { - *Shadow = 0; // fully addressable - } else if (i >= Size) { - *Shadow = Magic; // unaddressable + DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n"); + + if (ClKeepUninstrumented) { + if (!res) { + // No instrumentation is done, no need for the duplicate. + if (UninstrumentedDuplicate) + UninstrumentedDuplicate->eraseFromParent(); } else { - *Shadow = Size - i; // first Size-i bytes are addressable + // The function was instrumented. We must have the duplicate. + assert(UninstrumentedDuplicate); + UninstrumentedDuplicate->setSection("NOASAN"); + assert(!F.hasSection()); + F.setSection("ASAN"); } } -} -void AddressSanitizer::PoisonStack(const ArrayRef &AllocaVec, - IRBuilder<> IRB, - Value *ShadowBase, bool DoPoison) { - size_t ShadowRZSize = RedzoneSize >> MappingScale; - assert(ShadowRZSize >= 1 && ShadowRZSize <= 4); - Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8); - Type *RZPtrTy = PointerType::get(RZTy, 0); - - Value *PoisonLeft = ConstantInt::get(RZTy, - ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize)); - Value *PoisonMid = ConstantInt::get(RZTy, - ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize)); - Value *PoisonRight = ConstantInt::get(RZTy, - ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize)); - - // poison the first red zone. - IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy)); - - // poison all other red zones. - uint64_t Pos = RedzoneSize; - for (size_t i = 0, n = AllocaVec.size(); i < n; i++) { - AllocaInst *AI = AllocaVec[i]; - uint64_t SizeInBytes = getAllocaSizeInBytes(AI); - uint64_t AlignedSize = getAlignedAllocaSize(AI); - assert(AlignedSize - SizeInBytes < RedzoneSize); - Value *Ptr = NULL; - - Pos += AlignedSize; - - assert(ShadowBase->getType() == IntptrTy); - if (SizeInBytes < AlignedSize) { - // Poison the partial redzone at right - Ptr = IRB.CreateAdd( - ShadowBase, ConstantInt::get(IntptrTy, - (Pos >> MappingScale) - ShadowRZSize)); - size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes); - uint32_t Poison = 0; - if (DoPoison) { - PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes, - RedzoneSize, - 1ULL << MappingScale, - kAsanStackPartialRedzoneMagic); - } - Value *PartialPoison = ConstantInt::get(RZTy, Poison); - IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy)); - } - - // Poison the full redzone at right. - Ptr = IRB.CreateAdd(ShadowBase, - ConstantInt::get(IntptrTy, Pos >> MappingScale)); - Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid; - IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy)); - - Pos += RedzoneSize; - } + return res; } // Workaround for bug 11395: we don't want to instrument stack in functions @@ -983,142 +1565,301 @@ bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) { return true; } -// Find all static Alloca instructions and put -// poisoned red zones around all of them. -// Then unpoison everything back before the function returns. -// -// Stack poisoning does not play well with exception handling. -// When an exception is thrown, we essentially bypass the code -// that unpoisones the stack. This is why the run-time library has -// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire -// stack in the interceptor. This however does not work inside the -// actual function which catches the exception. Most likely because the -// compiler hoists the load of the shadow value somewhere too high. -// This causes asan to report a non-existing bug on 453.povray. -// It sounds like an LLVM bug. -bool AddressSanitizer::poisonStackInFunction(Module &M, Function &F) { - if (!ClStack) return false; - SmallVector AllocaVec; - SmallVector RetVec; - uint64_t TotalSize = 0; - - // Filter out Alloca instructions we want (and can) handle. - // Collect Ret instructions. - for (Function::iterator FI = F.begin(), FE = F.end(); - FI != FE; ++FI) { - BasicBlock &BB = *FI; - for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); - BI != BE; ++BI) { - if (isa(BI)) { - RetVec.push_back(BI); - continue; - } +void FunctionStackPoisoner::initializeCallbacks(Module &M) { + IRBuilder<> IRB(*C); + for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) { + std::string Suffix = itostr(i); + AsanStackMallocFunc[i] = checkInterfaceFunction( + M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy, + IntptrTy, IntptrTy, NULL)); + AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction( + kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy, + IntptrTy, IntptrTy, NULL)); + } + AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction( + kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); + AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction( + kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); +} - AllocaInst *AI = dyn_cast(BI); - if (!AI) continue; - if (AI->isArrayAllocation()) continue; - if (!AI->isStaticAlloca()) continue; - if (!AI->getAllocatedType()->isSized()) continue; - if (AI->getAlignment() > RedzoneSize) continue; - AllocaVec.push_back(AI); - uint64_t AlignedSize = getAlignedAllocaSize(AI); - TotalSize += AlignedSize; +void +FunctionStackPoisoner::poisonRedZones(ArrayRef ShadowBytes, + IRBuilder<> &IRB, Value *ShadowBase, + bool DoPoison) { + size_t n = ShadowBytes.size(); + size_t i = 0; + // We need to (un)poison n bytes of stack shadow. Poison as many as we can + // using 64-bit stores (if we are on 64-bit arch), then poison the rest + // with 32-bit stores, then with 16-byte stores, then with 8-byte stores. + for (size_t LargeStoreSizeInBytes = ASan.LongSize / 8; + LargeStoreSizeInBytes != 0; LargeStoreSizeInBytes /= 2) { + for (; i + LargeStoreSizeInBytes - 1 < n; i += LargeStoreSizeInBytes) { + uint64_t Val = 0; + for (size_t j = 0; j < LargeStoreSizeInBytes; j++) { + if (ASan.DL->isLittleEndian()) + Val |= (uint64_t)ShadowBytes[i + j] << (8 * j); + else + Val = (Val << 8) | ShadowBytes[i + j]; + } + if (!Val) continue; + Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i)); + Type *StoreTy = Type::getIntNTy(*C, LargeStoreSizeInBytes * 8); + Value *Poison = ConstantInt::get(StoreTy, DoPoison ? Val : 0); + IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, StoreTy->getPointerTo())); } } +} + +// Fake stack allocator (asan_fake_stack.h) has 11 size classes +// for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass +static int StackMallocSizeClass(uint64_t LocalStackSize) { + assert(LocalStackSize <= kMaxStackMallocSize); + uint64_t MaxSize = kMinStackMallocSize; + for (int i = 0; ; i++, MaxSize *= 2) + if (LocalStackSize <= MaxSize) + return i; + llvm_unreachable("impossible LocalStackSize"); +} - if (AllocaVec.empty()) return false; +// Set Size bytes starting from ShadowBase to kAsanStackAfterReturnMagic. +// We can not use MemSet intrinsic because it may end up calling the actual +// memset. Size is a multiple of 8. +// Currently this generates 8-byte stores on x86_64; it may be better to +// generate wider stores. +void FunctionStackPoisoner::SetShadowToStackAfterReturnInlined( + IRBuilder<> &IRB, Value *ShadowBase, int Size) { + assert(!(Size % 8)); + assert(kAsanStackAfterReturnMagic == 0xf5); + for (int i = 0; i < Size; i += 8) { + Value *p = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i)); + IRB.CreateStore(ConstantInt::get(IRB.getInt64Ty(), 0xf5f5f5f5f5f5f5f5ULL), + IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo())); + } +} - uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize; +static DebugLoc getFunctionEntryDebugLocation(Function &F) { + for (const auto &Inst : F.getEntryBlock()) + if (!isa(Inst)) + return Inst.getDebugLoc(); + return DebugLoc(); +} - bool DoStackMalloc = ClUseAfterReturn - && LocalStackSize <= kMaxStackMallocSize; +void FunctionStackPoisoner::poisonStack() { + int StackMallocIdx = -1; + DebugLoc EntryDebugLocation = getFunctionEntryDebugLocation(F); + assert(AllocaVec.size() > 0); Instruction *InsBefore = AllocaVec[0]; IRBuilder<> IRB(InsBefore); - + IRB.SetCurrentDebugLocation(EntryDebugLocation); + + SmallVector SVD; + SVD.reserve(AllocaVec.size()); + for (AllocaInst *AI : AllocaVec) { + ASanStackVariableDescription D = { AI->getName().data(), + getAllocaSizeInBytes(AI), + AI->getAlignment(), AI, 0}; + SVD.push_back(D); + } + // Minimal header size (left redzone) is 4 pointers, + // i.e. 32 bytes on 64-bit platforms and 16 bytes in 32-bit platforms. + size_t MinHeaderSize = ASan.LongSize / 2; + ASanStackFrameLayout L; + ComputeASanStackFrameLayout(SVD, 1UL << Mapping.Scale, MinHeaderSize, &L); + DEBUG(dbgs() << L.DescriptionString << " --- " << L.FrameSize << "\n"); + uint64_t LocalStackSize = L.FrameSize; + bool DoStackMalloc = + ClUseAfterReturn && LocalStackSize <= kMaxStackMallocSize; Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize); AllocaInst *MyAlloca = new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore); - MyAlloca->setAlignment(RedzoneSize); + MyAlloca->setDebugLoc(EntryDebugLocation); + assert((ClRealignStack & (ClRealignStack - 1)) == 0); + size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack); + MyAlloca->setAlignment(FrameAlignment); assert(MyAlloca->isStaticAlloca()); Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy); Value *LocalStackBase = OrigStackBase; if (DoStackMalloc) { - Value *AsanStackMallocFunc = M.getOrInsertFunction( - kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL); - LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc, + // LocalStackBase = OrigStackBase + // if (__asan_option_detect_stack_use_after_return) + // LocalStackBase = __asan_stack_malloc_N(LocalStackBase, OrigStackBase); + StackMallocIdx = StackMallocSizeClass(LocalStackSize); + assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass); + Constant *OptionDetectUAR = F.getParent()->getOrInsertGlobal( + kAsanOptionDetectUAR, IRB.getInt32Ty()); + Value *Cmp = IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR), + Constant::getNullValue(IRB.getInt32Ty())); + Instruction *Term = SplitBlockAndInsertIfThen(Cmp, InsBefore, false); + BasicBlock *CmpBlock = cast(Cmp)->getParent(); + IRBuilder<> IRBIf(Term); + IRBIf.SetCurrentDebugLocation(EntryDebugLocation); + LocalStackBase = IRBIf.CreateCall2( + AsanStackMallocFunc[StackMallocIdx], ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase); + BasicBlock *SetBlock = cast(LocalStackBase)->getParent(); + IRB.SetInsertPoint(InsBefore); + IRB.SetCurrentDebugLocation(EntryDebugLocation); + PHINode *Phi = IRB.CreatePHI(IntptrTy, 2); + Phi->addIncoming(OrigStackBase, CmpBlock); + Phi->addIncoming(LocalStackBase, SetBlock); + LocalStackBase = Phi; } - // This string will be parsed by the run-time (DescribeStackAddress). - SmallString<2048> StackDescriptionStorage; - raw_svector_ostream StackDescription(StackDescriptionStorage); - StackDescription << F.getName() << " " << AllocaVec.size() << " "; + // Insert poison calls for lifetime intrinsics for alloca. + bool HavePoisonedAllocas = false; + for (const auto &APC : AllocaPoisonCallVec) { + assert(APC.InsBefore); + assert(APC.AI); + IRBuilder<> IRB(APC.InsBefore); + poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison); + HavePoisonedAllocas |= APC.DoPoison; + } - uint64_t Pos = RedzoneSize; // Replace Alloca instructions with base+offset. - for (size_t i = 0, n = AllocaVec.size(); i < n; i++) { - AllocaInst *AI = AllocaVec[i]; - uint64_t SizeInBytes = getAllocaSizeInBytes(AI); - StringRef Name = AI->getName(); - StackDescription << Pos << " " << SizeInBytes << " " - << Name.size() << " " << Name << " "; - uint64_t AlignedSize = getAlignedAllocaSize(AI); - assert((AlignedSize % RedzoneSize) == 0); - AI->replaceAllUsesWith( - IRB.CreateIntToPtr( - IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)), - AI->getType())); - Pos += AlignedSize + RedzoneSize; + for (const auto &Desc : SVD) { + AllocaInst *AI = Desc.AI; + Value *NewAllocaPtr = IRB.CreateIntToPtr( + IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)), + AI->getType()); + replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB); + AI->replaceAllUsesWith(NewAllocaPtr); } - assert(Pos == LocalStackSize); - // Write the Magic value and the frame description constant to the redzone. + // The left-most redzone has enough space for at least 4 pointers. + // Write the Magic value to redzone[0]. Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy); IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic), BasePlus0); - Value *BasePlus1 = IRB.CreateAdd(LocalStackBase, - ConstantInt::get(IntptrTy, LongSize/8)); - BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy); - Value *Description = IRB.CreatePointerCast( - createPrivateGlobalForString(M, StackDescription.str()), - IntptrTy); + // Write the frame description constant to redzone[1]. + Value *BasePlus1 = IRB.CreateIntToPtr( + IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)), + IntptrPtrTy); + GlobalVariable *StackDescriptionGlobal = + createPrivateGlobalForString(*F.getParent(), L.DescriptionString, + /*AllowMerging*/true); + Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, + IntptrTy); IRB.CreateStore(Description, BasePlus1); + // Write the PC to redzone[2]. + Value *BasePlus2 = IRB.CreateIntToPtr( + IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, + 2 * ASan.LongSize/8)), + IntptrPtrTy); + IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2); // Poison the stack redzones at the entry. - Value *ShadowBase = memToShadow(LocalStackBase, IRB); - PoisonStack(ArrayRef(AllocaVec), IRB, ShadowBase, true); + Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB); + poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true); - Value *AsanStackFreeFunc = NULL; - if (DoStackMalloc) { - AsanStackFreeFunc = M.getOrInsertFunction( - kAsanStackFreeName, IRB.getVoidTy(), - IntptrTy, IntptrTy, IntptrTy, NULL); - } - - // Unpoison the stack before all ret instructions. - for (size_t i = 0, n = RetVec.size(); i < n; i++) { - Instruction *Ret = RetVec[i]; + // (Un)poison the stack before all ret instructions. + for (auto Ret : RetVec) { IRBuilder<> IRBRet(Ret); - // Mark the current frame as retired. IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic), BasePlus0); - // Unpoison the stack. - PoisonStack(ArrayRef(AllocaVec), IRBRet, ShadowBase, false); - if (DoStackMalloc) { - IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase, - ConstantInt::get(IntptrTy, LocalStackSize), - OrigStackBase); + assert(StackMallocIdx >= 0); + // if LocalStackBase != OrigStackBase: + // // In use-after-return mode, poison the whole stack frame. + // if StackMallocIdx <= 4 + // // For small sizes inline the whole thing: + // memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize); + // **SavedFlagPtr(LocalStackBase) = 0 + // else + // __asan_stack_free_N(LocalStackBase, OrigStackBase) + // else + // + Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase); + TerminatorInst *ThenTerm, *ElseTerm; + SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm); + + IRBuilder<> IRBPoison(ThenTerm); + if (StackMallocIdx <= 4) { + int ClassSize = kMinStackMallocSize << StackMallocIdx; + SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase, + ClassSize >> Mapping.Scale); + Value *SavedFlagPtrPtr = IRBPoison.CreateAdd( + LocalStackBase, + ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8)); + Value *SavedFlagPtr = IRBPoison.CreateLoad( + IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy)); + IRBPoison.CreateStore( + Constant::getNullValue(IRBPoison.getInt8Ty()), + IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy())); + } else { + // For larger frames call __asan_stack_free_*. + IRBPoison.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase, + ConstantInt::get(IntptrTy, LocalStackSize), + OrigStackBase); + } + + IRBuilder<> IRBElse(ElseTerm); + poisonRedZones(L.ShadowBytes, IRBElse, ShadowBase, false); + } else if (HavePoisonedAllocas) { + // If we poisoned some allocas in llvm.lifetime analysis, + // unpoison whole stack frame now. + assert(LocalStackBase == OrigStackBase); + poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false); + } else { + poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false); } } - if (ClDebugStack) { - DEBUG(dbgs() << F); - } + // We are done. Remove the old unused alloca instructions. + for (auto AI : AllocaVec) + AI->eraseFromParent(); +} - return true; +void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size, + IRBuilder<> &IRB, bool DoPoison) { + // For now just insert the call to ASan runtime. + Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy); + Value *SizeArg = ConstantInt::get(IntptrTy, Size); + IRB.CreateCall2(DoPoison ? AsanPoisonStackMemoryFunc + : AsanUnpoisonStackMemoryFunc, + AddrArg, SizeArg); +} + +// Handling llvm.lifetime intrinsics for a given %alloca: +// (1) collect all llvm.lifetime.xxx(%size, %value) describing the alloca. +// (2) if %size is constant, poison memory for llvm.lifetime.end (to detect +// invalid accesses) and unpoison it for llvm.lifetime.start (the memory +// could be poisoned by previous llvm.lifetime.end instruction, as the +// variable may go in and out of scope several times, e.g. in loops). +// (3) if we poisoned at least one %alloca in a function, +// unpoison the whole stack frame at function exit. + +AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) { + if (AllocaInst *AI = dyn_cast(V)) + // We're intested only in allocas we can handle. + return isInterestingAlloca(*AI) ? AI : nullptr; + // See if we've already calculated (or started to calculate) alloca for a + // given value. + AllocaForValueMapTy::iterator I = AllocaForValue.find(V); + if (I != AllocaForValue.end()) + return I->second; + // Store 0 while we're calculating alloca for value V to avoid + // infinite recursion if the value references itself. + AllocaForValue[V] = nullptr; + AllocaInst *Res = nullptr; + if (CastInst *CI = dyn_cast(V)) + Res = findAllocaForValue(CI->getOperand(0)); + else if (PHINode *PN = dyn_cast(V)) { + for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { + Value *IncValue = PN->getIncomingValue(i); + // Allow self-referencing phi-nodes. + if (IncValue == PN) continue; + AllocaInst *IncValueAI = findAllocaForValue(IncValue); + // AI for incoming values should exist and should all be equal. + if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res)) + return nullptr; + Res = IncValueAI; + } + } + if (Res) + AllocaForValue[V] = Res; + return Res; }