1234285Sdim//===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===// 2234285Sdim// 3234285Sdim// The LLVM Compiler Infrastructure 4234285Sdim// 5234285Sdim// This file is distributed under the University of Illinois Open Source 6234285Sdim// License. See LICENSE.TXT for details. 7234285Sdim// 8234285Sdim//===----------------------------------------------------------------------===// 9234285Sdim// 10234285Sdim// This file is a part of AddressSanitizer, an address sanity checker. 11234285Sdim// Details of the algorithm: 12234285Sdim// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm 13234285Sdim// 14234285Sdim//===----------------------------------------------------------------------===// 15234285Sdim 16234285Sdim#define DEBUG_TYPE "asan" 17234285Sdim 18249423Sdim#include "llvm/Transforms/Instrumentation.h" 19234285Sdim#include "llvm/ADT/ArrayRef.h" 20249423Sdim#include "llvm/ADT/DenseMap.h" 21249423Sdim#include "llvm/ADT/DepthFirstIterator.h" 22234285Sdim#include "llvm/ADT/OwningPtr.h" 23234285Sdim#include "llvm/ADT/SmallSet.h" 24234285Sdim#include "llvm/ADT/SmallString.h" 25234285Sdim#include "llvm/ADT/SmallVector.h" 26263508Sdim#include "llvm/ADT/Statistic.h" 27234285Sdim#include "llvm/ADT/StringExtras.h" 28239462Sdim#include "llvm/ADT/Triple.h" 29249423Sdim#include "llvm/DIBuilder.h" 30249423Sdim#include "llvm/IR/DataLayout.h" 31249423Sdim#include "llvm/IR/Function.h" 32249423Sdim#include "llvm/IR/IRBuilder.h" 33249423Sdim#include "llvm/IR/InlineAsm.h" 34249423Sdim#include "llvm/IR/IntrinsicInst.h" 35249423Sdim#include "llvm/IR/LLVMContext.h" 36249423Sdim#include "llvm/IR/Module.h" 37249423Sdim#include "llvm/IR/Type.h" 38249423Sdim#include "llvm/InstVisitor.h" 39249423Sdim#include "llvm/Support/CallSite.h" 40234285Sdim#include "llvm/Support/CommandLine.h" 41234285Sdim#include "llvm/Support/DataTypes.h" 42234285Sdim#include "llvm/Support/Debug.h" 43263508Sdim#include "llvm/Support/Endian.h" 44234285Sdim#include "llvm/Support/raw_ostream.h" 45234285Sdim#include "llvm/Support/system_error.h" 46234285Sdim#include "llvm/Transforms/Utils/BasicBlockUtils.h" 47263508Sdim#include "llvm/Transforms/Utils/Cloning.h" 48249423Sdim#include "llvm/Transforms/Utils/Local.h" 49234285Sdim#include "llvm/Transforms/Utils/ModuleUtils.h" 50263508Sdim#include "llvm/Transforms/Utils/SpecialCaseList.h" 51249423Sdim#include <algorithm> 52234285Sdim#include <string> 53234285Sdim 54234285Sdimusing namespace llvm; 55234285Sdim 56234285Sdimstatic const uint64_t kDefaultShadowScale = 3; 57234285Sdimstatic const uint64_t kDefaultShadowOffset32 = 1ULL << 29; 58234285Sdimstatic const uint64_t kDefaultShadowOffset64 = 1ULL << 44; 59249423Sdimstatic const uint64_t kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G. 60249423Sdimstatic const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41; 61263508Sdimstatic const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000; 62234285Sdim 63263508Sdimstatic const size_t kMinStackMallocSize = 1 << 6; // 64B 64234285Sdimstatic const size_t kMaxStackMallocSize = 1 << 16; // 64K 65234285Sdimstatic const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3; 66234285Sdimstatic const uintptr_t kRetiredStackFrameMagic = 0x45E0360E; 67234285Sdim 68263508Sdimstatic const char *const kAsanModuleCtorName = "asan.module_ctor"; 69263508Sdimstatic const char *const kAsanModuleDtorName = "asan.module_dtor"; 70263508Sdimstatic const int kAsanCtorAndCtorPriority = 1; 71263508Sdimstatic const char *const kAsanReportErrorTemplate = "__asan_report_"; 72263508Sdimstatic const char *const kAsanReportLoadN = "__asan_report_load_n"; 73263508Sdimstatic const char *const kAsanReportStoreN = "__asan_report_store_n"; 74263508Sdimstatic const char *const kAsanRegisterGlobalsName = "__asan_register_globals"; 75263508Sdimstatic const char *const kAsanUnregisterGlobalsName = 76263508Sdim "__asan_unregister_globals"; 77263508Sdimstatic const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init"; 78263508Sdimstatic const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init"; 79263508Sdimstatic const char *const kAsanInitName = "__asan_init_v3"; 80263508Sdimstatic const char *const kAsanCovName = "__sanitizer_cov"; 81263508Sdimstatic const char *const kAsanHandleNoReturnName = "__asan_handle_no_return"; 82263508Sdimstatic const char *const kAsanMappingOffsetName = "__asan_mapping_offset"; 83263508Sdimstatic const char *const kAsanMappingScaleName = "__asan_mapping_scale"; 84263508Sdimstatic const int kMaxAsanStackMallocSizeClass = 10; 85263508Sdimstatic const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_"; 86263508Sdimstatic const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_"; 87263508Sdimstatic const char *const kAsanGenPrefix = "__asan_gen_"; 88263508Sdimstatic const char *const kAsanPoisonStackMemoryName = 89263508Sdim "__asan_poison_stack_memory"; 90263508Sdimstatic const char *const kAsanUnpoisonStackMemoryName = 91249423Sdim "__asan_unpoison_stack_memory"; 92234285Sdim 93263508Sdimstatic const char *const kAsanOptionDetectUAR = 94263508Sdim "__asan_option_detect_stack_use_after_return"; 95263508Sdim 96263508Sdim// These constants must match the definitions in the run-time library. 97234285Sdimstatic const int kAsanStackLeftRedzoneMagic = 0xf1; 98234285Sdimstatic const int kAsanStackMidRedzoneMagic = 0xf2; 99234285Sdimstatic const int kAsanStackRightRedzoneMagic = 0xf3; 100234285Sdimstatic const int kAsanStackPartialRedzoneMagic = 0xf4; 101263508Sdim#ifndef NDEBUG 102263508Sdimstatic const int kAsanStackAfterReturnMagic = 0xf5; 103263508Sdim#endif 104234285Sdim 105239462Sdim// Accesses sizes are powers of two: 1, 2, 4, 8, 16. 106239462Sdimstatic const size_t kNumberOfAccessSizes = 5; 107239462Sdim 108234285Sdim// Command-line flags. 109234285Sdim 110234285Sdim// This flag may need to be replaced with -f[no-]asan-reads. 111234285Sdimstatic cl::opt<bool> ClInstrumentReads("asan-instrument-reads", 112234285Sdim cl::desc("instrument read instructions"), cl::Hidden, cl::init(true)); 113234285Sdimstatic cl::opt<bool> ClInstrumentWrites("asan-instrument-writes", 114234285Sdim cl::desc("instrument write instructions"), cl::Hidden, cl::init(true)); 115239462Sdimstatic cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics", 116239462Sdim cl::desc("instrument atomic instructions (rmw, cmpxchg)"), 117239462Sdim cl::Hidden, cl::init(true)); 118239462Sdimstatic cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path", 119239462Sdim cl::desc("use instrumentation with slow path for all accesses"), 120239462Sdim cl::Hidden, cl::init(false)); 121239462Sdim// This flag limits the number of instructions to be instrumented 122239462Sdim// in any given BB. Normally, this should be set to unlimited (INT_MAX), 123239462Sdim// but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary 124239462Sdim// set it to 10000. 125239462Sdimstatic cl::opt<int> ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb", 126239462Sdim cl::init(10000), 127239462Sdim cl::desc("maximal number of instructions to instrument in any given BB"), 128239462Sdim cl::Hidden); 129234285Sdim// This flag may need to be replaced with -f[no]asan-stack. 130234285Sdimstatic cl::opt<bool> ClStack("asan-stack", 131234285Sdim cl::desc("Handle stack memory"), cl::Hidden, cl::init(true)); 132234285Sdim// This flag may need to be replaced with -f[no]asan-use-after-return. 133234285Sdimstatic cl::opt<bool> ClUseAfterReturn("asan-use-after-return", 134234285Sdim cl::desc("Check return-after-free"), cl::Hidden, cl::init(false)); 135234285Sdim// This flag may need to be replaced with -f[no]asan-globals. 136234285Sdimstatic cl::opt<bool> ClGlobals("asan-globals", 137234285Sdim cl::desc("Handle global objects"), cl::Hidden, cl::init(true)); 138263508Sdimstatic cl::opt<bool> ClCoverage("asan-coverage", 139263508Sdim cl::desc("ASan coverage"), cl::Hidden, cl::init(false)); 140243830Sdimstatic cl::opt<bool> ClInitializers("asan-initialization-order", 141243830Sdim cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false)); 142234285Sdimstatic cl::opt<bool> ClMemIntrin("asan-memintrin", 143234285Sdim cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true)); 144249423Sdimstatic cl::opt<bool> ClRealignStack("asan-realign-stack", 145249423Sdim cl::desc("Realign stack to 32"), cl::Hidden, cl::init(true)); 146249423Sdimstatic cl::opt<std::string> ClBlacklistFile("asan-blacklist", 147249423Sdim cl::desc("File containing the list of objects to ignore " 148234285Sdim "during instrumentation"), cl::Hidden); 149234285Sdim 150263508Sdim// This is an experimental feature that will allow to choose between 151263508Sdim// instrumented and non-instrumented code at link-time. 152263508Sdim// If this option is on, just before instrumenting a function we create its 153263508Sdim// clone; if the function is not changed by asan the clone is deleted. 154263508Sdim// If we end up with a clone, we put the instrumented function into a section 155263508Sdim// called "ASAN" and the uninstrumented function into a section called "NOASAN". 156263508Sdim// 157263508Sdim// This is still a prototype, we need to figure out a way to keep two copies of 158263508Sdim// a function so that the linker can easily choose one of them. 159263508Sdimstatic cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions", 160263508Sdim cl::desc("Keep uninstrumented copies of functions"), 161263508Sdim cl::Hidden, cl::init(false)); 162263508Sdim 163234285Sdim// These flags allow to change the shadow mapping. 164234285Sdim// The shadow mapping looks like 165234285Sdim// Shadow = (Mem >> scale) + (1 << offset_log) 166234285Sdimstatic cl::opt<int> ClMappingScale("asan-mapping-scale", 167234285Sdim cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0)); 168234285Sdimstatic cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log", 169234285Sdim cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1)); 170249423Sdimstatic cl::opt<bool> ClShort64BitOffset("asan-short-64bit-mapping-offset", 171249423Sdim cl::desc("Use short immediate constant as the mapping offset for 64bit"), 172249423Sdim cl::Hidden, cl::init(true)); 173234285Sdim 174234285Sdim// Optimization flags. Not user visible, used mostly for testing 175234285Sdim// and benchmarking the tool. 176234285Sdimstatic cl::opt<bool> ClOpt("asan-opt", 177234285Sdim cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true)); 178234285Sdimstatic cl::opt<bool> ClOptSameTemp("asan-opt-same-temp", 179234285Sdim cl::desc("Instrument the same temp just once"), cl::Hidden, 180234285Sdim cl::init(true)); 181234285Sdimstatic cl::opt<bool> ClOptGlobals("asan-opt-globals", 182234285Sdim cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true)); 183234285Sdim 184249423Sdimstatic cl::opt<bool> ClCheckLifetime("asan-check-lifetime", 185249423Sdim cl::desc("Use llvm.lifetime intrinsics to insert extra checks"), 186249423Sdim cl::Hidden, cl::init(false)); 187249423Sdim 188234285Sdim// Debug flags. 189234285Sdimstatic cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden, 190234285Sdim cl::init(0)); 191234285Sdimstatic cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"), 192234285Sdim cl::Hidden, cl::init(0)); 193234285Sdimstatic cl::opt<std::string> ClDebugFunc("asan-debug-func", 194234285Sdim cl::Hidden, cl::desc("Debug func")); 195234285Sdimstatic cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"), 196234285Sdim cl::Hidden, cl::init(-1)); 197234285Sdimstatic cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"), 198234285Sdim cl::Hidden, cl::init(-1)); 199234285Sdim 200263508SdimSTATISTIC(NumInstrumentedReads, "Number of instrumented reads"); 201263508SdimSTATISTIC(NumInstrumentedWrites, "Number of instrumented writes"); 202263508SdimSTATISTIC(NumOptimizedAccessesToGlobalArray, 203263508Sdim "Number of optimized accesses to global arrays"); 204263508SdimSTATISTIC(NumOptimizedAccessesToGlobalVar, 205263508Sdim "Number of optimized accesses to global vars"); 206263508Sdim 207234285Sdimnamespace { 208249423Sdim/// A set of dynamically initialized globals extracted from metadata. 209249423Sdimclass SetOfDynamicallyInitializedGlobals { 210249423Sdim public: 211249423Sdim void Init(Module& M) { 212249423Sdim // Clang generates metadata identifying all dynamically initialized globals. 213249423Sdim NamedMDNode *DynamicGlobals = 214249423Sdim M.getNamedMetadata("llvm.asan.dynamically_initialized_globals"); 215249423Sdim if (!DynamicGlobals) 216249423Sdim return; 217249423Sdim for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) { 218249423Sdim MDNode *MDN = DynamicGlobals->getOperand(i); 219249423Sdim assert(MDN->getNumOperands() == 1); 220249423Sdim Value *VG = MDN->getOperand(0); 221249423Sdim // The optimizer may optimize away a global entirely, in which case we 222249423Sdim // cannot instrument access to it. 223249423Sdim if (!VG) 224249423Sdim continue; 225249423Sdim DynInitGlobals.insert(cast<GlobalVariable>(VG)); 226249423Sdim } 227249423Sdim } 228249423Sdim bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; } 229249423Sdim private: 230249423Sdim SmallSet<GlobalValue*, 32> DynInitGlobals; 231249423Sdim}; 232249423Sdim 233249423Sdim/// This struct defines the shadow mapping using the rule: 234249423Sdim/// shadow = (mem >> Scale) ADD-or-OR Offset. 235249423Sdimstruct ShadowMapping { 236249423Sdim int Scale; 237249423Sdim uint64_t Offset; 238249423Sdim bool OrShadowOffset; 239249423Sdim}; 240249423Sdim 241249423Sdimstatic ShadowMapping getShadowMapping(const Module &M, int LongSize, 242249423Sdim bool ZeroBaseShadow) { 243249423Sdim llvm::Triple TargetTriple(M.getTargetTriple()); 244249423Sdim bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android; 245249423Sdim bool IsMacOSX = TargetTriple.getOS() == llvm::Triple::MacOSX; 246263508Sdim bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 || 247263508Sdim TargetTriple.getArch() == llvm::Triple::ppc64le; 248249423Sdim bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64; 249263508Sdim bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips || 250263508Sdim TargetTriple.getArch() == llvm::Triple::mipsel; 251249423Sdim 252249423Sdim ShadowMapping Mapping; 253249423Sdim 254249423Sdim // OR-ing shadow offset if more efficient (at least on x86), 255249423Sdim // but on ppc64 we have to use add since the shadow offset is not neccesary 256249423Sdim // 1/8-th of the address space. 257249423Sdim Mapping.OrShadowOffset = !IsPPC64 && !ClShort64BitOffset; 258249423Sdim 259249423Sdim Mapping.Offset = (IsAndroid || ZeroBaseShadow) ? 0 : 260263508Sdim (LongSize == 32 ? 261263508Sdim (IsMIPS32 ? kMIPS32_ShadowOffset32 : kDefaultShadowOffset32) : 262249423Sdim IsPPC64 ? kPPC64_ShadowOffset64 : kDefaultShadowOffset64); 263249423Sdim if (!ZeroBaseShadow && ClShort64BitOffset && IsX86_64 && !IsMacOSX) { 264249423Sdim assert(LongSize == 64); 265249423Sdim Mapping.Offset = kDefaultShort64bitShadowOffset; 266249423Sdim } 267249423Sdim if (!ZeroBaseShadow && ClMappingOffsetLog >= 0) { 268249423Sdim // Zero offset log is the special case. 269249423Sdim Mapping.Offset = (ClMappingOffsetLog == 0) ? 0 : 1ULL << ClMappingOffsetLog; 270249423Sdim } 271249423Sdim 272249423Sdim Mapping.Scale = kDefaultShadowScale; 273249423Sdim if (ClMappingScale) { 274249423Sdim Mapping.Scale = ClMappingScale; 275249423Sdim } 276249423Sdim 277249423Sdim return Mapping; 278249423Sdim} 279249423Sdim 280249423Sdimstatic size_t RedzoneSizeForScale(int MappingScale) { 281249423Sdim // Redzone used for stack and globals is at least 32 bytes. 282249423Sdim // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively. 283249423Sdim return std::max(32U, 1U << MappingScale); 284249423Sdim} 285249423Sdim 286234285Sdim/// AddressSanitizer: instrument the code in module to find memory bugs. 287243830Sdimstruct AddressSanitizer : public FunctionPass { 288249423Sdim AddressSanitizer(bool CheckInitOrder = true, 289249423Sdim bool CheckUseAfterReturn = false, 290249423Sdim bool CheckLifetime = false, 291249423Sdim StringRef BlacklistFile = StringRef(), 292249423Sdim bool ZeroBaseShadow = false) 293249423Sdim : FunctionPass(ID), 294249423Sdim CheckInitOrder(CheckInitOrder || ClInitializers), 295249423Sdim CheckUseAfterReturn(CheckUseAfterReturn || ClUseAfterReturn), 296249423Sdim CheckLifetime(CheckLifetime || ClCheckLifetime), 297249423Sdim BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile 298249423Sdim : BlacklistFile), 299249423Sdim ZeroBaseShadow(ZeroBaseShadow) {} 300249423Sdim virtual const char *getPassName() const { 301249423Sdim return "AddressSanitizerFunctionPass"; 302249423Sdim } 303243830Sdim void instrumentMop(Instruction *I); 304249423Sdim void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore, 305249423Sdim Value *Addr, uint32_t TypeSize, bool IsWrite, 306249423Sdim Value *SizeArgument); 307239462Sdim Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong, 308239462Sdim Value *ShadowValue, uint32_t TypeSize); 309239462Sdim Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr, 310249423Sdim bool IsWrite, size_t AccessSizeIndex, 311249423Sdim Value *SizeArgument); 312243830Sdim bool instrumentMemIntrinsic(MemIntrinsic *MI); 313243830Sdim void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr, 314239462Sdim Value *Size, 315234285Sdim Instruction *InsertBefore, bool IsWrite); 316234285Sdim Value *memToShadow(Value *Shadow, IRBuilder<> &IRB); 317243830Sdim bool runOnFunction(Function &F); 318234285Sdim bool maybeInsertAsanInitAtFunctionEntry(Function &F); 319249423Sdim void emitShadowMapping(Module &M, IRBuilder<> &IRB) const; 320243830Sdim virtual bool doInitialization(Module &M); 321234285Sdim static char ID; // Pass identification, replacement for typeid 322234285Sdim 323234285Sdim private: 324249423Sdim void initializeCallbacks(Module &M); 325234285Sdim 326243830Sdim bool ShouldInstrumentGlobal(GlobalVariable *G); 327234285Sdim bool LooksLikeCodeInBug11395(Instruction *I); 328243830Sdim void FindDynamicInitializers(Module &M); 329263508Sdim bool GlobalIsLinkerInitialized(GlobalVariable *G); 330263508Sdim bool InjectCoverage(Function &F); 331234285Sdim 332249423Sdim bool CheckInitOrder; 333249423Sdim bool CheckUseAfterReturn; 334249423Sdim bool CheckLifetime; 335249423Sdim SmallString<64> BlacklistFile; 336249423Sdim bool ZeroBaseShadow; 337249423Sdim 338234285Sdim LLVMContext *C; 339243830Sdim DataLayout *TD; 340234285Sdim int LongSize; 341234285Sdim Type *IntptrTy; 342249423Sdim ShadowMapping Mapping; 343234285Sdim Function *AsanCtorFunction; 344234285Sdim Function *AsanInitFunction; 345243830Sdim Function *AsanHandleNoReturnFunc; 346263508Sdim Function *AsanCovFunction; 347263508Sdim OwningPtr<SpecialCaseList> BL; 348239462Sdim // This array is indexed by AccessIsWrite and log2(AccessSize). 349239462Sdim Function *AsanErrorCallback[2][kNumberOfAccessSizes]; 350249423Sdim // This array is indexed by AccessIsWrite. 351249423Sdim Function *AsanErrorCallbackSized[2]; 352239462Sdim InlineAsm *EmptyAsm; 353249423Sdim SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals; 354249423Sdim 355249423Sdim friend struct FunctionStackPoisoner; 356234285Sdim}; 357239462Sdim 358249423Sdimclass AddressSanitizerModule : public ModulePass { 359249423Sdim public: 360249423Sdim AddressSanitizerModule(bool CheckInitOrder = true, 361249423Sdim StringRef BlacklistFile = StringRef(), 362249423Sdim bool ZeroBaseShadow = false) 363249423Sdim : ModulePass(ID), 364249423Sdim CheckInitOrder(CheckInitOrder || ClInitializers), 365249423Sdim BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile 366249423Sdim : BlacklistFile), 367249423Sdim ZeroBaseShadow(ZeroBaseShadow) {} 368249423Sdim bool runOnModule(Module &M); 369249423Sdim static char ID; // Pass identification, replacement for typeid 370249423Sdim virtual const char *getPassName() const { 371249423Sdim return "AddressSanitizerModule"; 372249423Sdim } 373249423Sdim 374249423Sdim private: 375249423Sdim void initializeCallbacks(Module &M); 376249423Sdim 377249423Sdim bool ShouldInstrumentGlobal(GlobalVariable *G); 378249423Sdim void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName); 379249423Sdim size_t RedzoneSize() const { 380249423Sdim return RedzoneSizeForScale(Mapping.Scale); 381249423Sdim } 382249423Sdim 383249423Sdim bool CheckInitOrder; 384249423Sdim SmallString<64> BlacklistFile; 385249423Sdim bool ZeroBaseShadow; 386249423Sdim 387263508Sdim OwningPtr<SpecialCaseList> BL; 388249423Sdim SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals; 389249423Sdim Type *IntptrTy; 390249423Sdim LLVMContext *C; 391249423Sdim DataLayout *TD; 392249423Sdim ShadowMapping Mapping; 393249423Sdim Function *AsanPoisonGlobals; 394249423Sdim Function *AsanUnpoisonGlobals; 395249423Sdim Function *AsanRegisterGlobals; 396249423Sdim Function *AsanUnregisterGlobals; 397249423Sdim}; 398249423Sdim 399249423Sdim// Stack poisoning does not play well with exception handling. 400249423Sdim// When an exception is thrown, we essentially bypass the code 401249423Sdim// that unpoisones the stack. This is why the run-time library has 402249423Sdim// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire 403249423Sdim// stack in the interceptor. This however does not work inside the 404249423Sdim// actual function which catches the exception. Most likely because the 405249423Sdim// compiler hoists the load of the shadow value somewhere too high. 406249423Sdim// This causes asan to report a non-existing bug on 453.povray. 407249423Sdim// It sounds like an LLVM bug. 408249423Sdimstruct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> { 409249423Sdim Function &F; 410249423Sdim AddressSanitizer &ASan; 411249423Sdim DIBuilder DIB; 412249423Sdim LLVMContext *C; 413249423Sdim Type *IntptrTy; 414249423Sdim Type *IntptrPtrTy; 415249423Sdim ShadowMapping Mapping; 416249423Sdim 417249423Sdim SmallVector<AllocaInst*, 16> AllocaVec; 418249423Sdim SmallVector<Instruction*, 8> RetVec; 419249423Sdim uint64_t TotalStackSize; 420249423Sdim unsigned StackAlignment; 421249423Sdim 422263508Sdim Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1], 423263508Sdim *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1]; 424249423Sdim Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc; 425249423Sdim 426249423Sdim // Stores a place and arguments of poisoning/unpoisoning call for alloca. 427249423Sdim struct AllocaPoisonCall { 428249423Sdim IntrinsicInst *InsBefore; 429263508Sdim AllocaInst *AI; 430249423Sdim uint64_t Size; 431249423Sdim bool DoPoison; 432249423Sdim }; 433249423Sdim SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec; 434249423Sdim 435249423Sdim // Maps Value to an AllocaInst from which the Value is originated. 436249423Sdim typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy; 437249423Sdim AllocaForValueMapTy AllocaForValue; 438249423Sdim 439249423Sdim FunctionStackPoisoner(Function &F, AddressSanitizer &ASan) 440249423Sdim : F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C), 441249423Sdim IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)), 442249423Sdim Mapping(ASan.Mapping), 443249423Sdim TotalStackSize(0), StackAlignment(1 << Mapping.Scale) {} 444249423Sdim 445249423Sdim bool runOnFunction() { 446249423Sdim if (!ClStack) return false; 447249423Sdim // Collect alloca, ret, lifetime instructions etc. 448249423Sdim for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()), 449249423Sdim DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) { 450249423Sdim BasicBlock *BB = *DI; 451249423Sdim visit(*BB); 452249423Sdim } 453249423Sdim if (AllocaVec.empty()) return false; 454249423Sdim 455249423Sdim initializeCallbacks(*F.getParent()); 456249423Sdim 457249423Sdim poisonStack(); 458249423Sdim 459249423Sdim if (ClDebugStack) { 460249423Sdim DEBUG(dbgs() << F); 461249423Sdim } 462249423Sdim return true; 463249423Sdim } 464249423Sdim 465249423Sdim // Finds all static Alloca instructions and puts 466249423Sdim // poisoned red zones around all of them. 467249423Sdim // Then unpoison everything back before the function returns. 468249423Sdim void poisonStack(); 469249423Sdim 470249423Sdim // ----------------------- Visitors. 471249423Sdim /// \brief Collect all Ret instructions. 472249423Sdim void visitReturnInst(ReturnInst &RI) { 473249423Sdim RetVec.push_back(&RI); 474249423Sdim } 475249423Sdim 476249423Sdim /// \brief Collect Alloca instructions we want (and can) handle. 477249423Sdim void visitAllocaInst(AllocaInst &AI) { 478249423Sdim if (!isInterestingAlloca(AI)) return; 479249423Sdim 480249423Sdim StackAlignment = std::max(StackAlignment, AI.getAlignment()); 481249423Sdim AllocaVec.push_back(&AI); 482263508Sdim uint64_t AlignedSize = getAlignedAllocaSize(&AI); 483249423Sdim TotalStackSize += AlignedSize; 484249423Sdim } 485249423Sdim 486249423Sdim /// \brief Collect lifetime intrinsic calls to check for use-after-scope 487249423Sdim /// errors. 488249423Sdim void visitIntrinsicInst(IntrinsicInst &II) { 489249423Sdim if (!ASan.CheckLifetime) return; 490249423Sdim Intrinsic::ID ID = II.getIntrinsicID(); 491249423Sdim if (ID != Intrinsic::lifetime_start && 492249423Sdim ID != Intrinsic::lifetime_end) 493249423Sdim return; 494249423Sdim // Found lifetime intrinsic, add ASan instrumentation if necessary. 495249423Sdim ConstantInt *Size = dyn_cast<ConstantInt>(II.getArgOperand(0)); 496249423Sdim // If size argument is undefined, don't do anything. 497249423Sdim if (Size->isMinusOne()) return; 498249423Sdim // Check that size doesn't saturate uint64_t and can 499249423Sdim // be stored in IntptrTy. 500249423Sdim const uint64_t SizeValue = Size->getValue().getLimitedValue(); 501249423Sdim if (SizeValue == ~0ULL || 502249423Sdim !ConstantInt::isValueValidForType(IntptrTy, SizeValue)) 503249423Sdim return; 504249423Sdim // Find alloca instruction that corresponds to llvm.lifetime argument. 505249423Sdim AllocaInst *AI = findAllocaForValue(II.getArgOperand(1)); 506249423Sdim if (!AI) return; 507249423Sdim bool DoPoison = (ID == Intrinsic::lifetime_end); 508263508Sdim AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison}; 509249423Sdim AllocaPoisonCallVec.push_back(APC); 510249423Sdim } 511249423Sdim 512249423Sdim // ---------------------- Helpers. 513249423Sdim void initializeCallbacks(Module &M); 514249423Sdim 515249423Sdim // Check if we want (and can) handle this alloca. 516263508Sdim bool isInterestingAlloca(AllocaInst &AI) const { 517249423Sdim return (!AI.isArrayAllocation() && 518249423Sdim AI.isStaticAlloca() && 519263508Sdim AI.getAlignment() <= RedzoneSize() && 520249423Sdim AI.getAllocatedType()->isSized()); 521249423Sdim } 522249423Sdim 523249423Sdim size_t RedzoneSize() const { 524249423Sdim return RedzoneSizeForScale(Mapping.Scale); 525249423Sdim } 526263508Sdim uint64_t getAllocaSizeInBytes(AllocaInst *AI) const { 527249423Sdim Type *Ty = AI->getAllocatedType(); 528249423Sdim uint64_t SizeInBytes = ASan.TD->getTypeAllocSize(Ty); 529249423Sdim return SizeInBytes; 530249423Sdim } 531263508Sdim uint64_t getAlignedSize(uint64_t SizeInBytes) const { 532249423Sdim size_t RZ = RedzoneSize(); 533249423Sdim return ((SizeInBytes + RZ - 1) / RZ) * RZ; 534249423Sdim } 535263508Sdim uint64_t getAlignedAllocaSize(AllocaInst *AI) const { 536249423Sdim uint64_t SizeInBytes = getAllocaSizeInBytes(AI); 537249423Sdim return getAlignedSize(SizeInBytes); 538249423Sdim } 539249423Sdim /// Finds alloca where the value comes from. 540249423Sdim AllocaInst *findAllocaForValue(Value *V); 541263508Sdim void poisonRedZones(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> &IRB, 542249423Sdim Value *ShadowBase, bool DoPoison); 543263508Sdim void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison); 544263508Sdim 545263508Sdim void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase, 546263508Sdim int Size); 547249423Sdim}; 548249423Sdim 549234285Sdim} // namespace 550234285Sdim 551234285Sdimchar AddressSanitizer::ID = 0; 552234285SdimINITIALIZE_PASS(AddressSanitizer, "asan", 553234285Sdim "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", 554234285Sdim false, false) 555249423SdimFunctionPass *llvm::createAddressSanitizerFunctionPass( 556249423Sdim bool CheckInitOrder, bool CheckUseAfterReturn, bool CheckLifetime, 557249423Sdim StringRef BlacklistFile, bool ZeroBaseShadow) { 558249423Sdim return new AddressSanitizer(CheckInitOrder, CheckUseAfterReturn, 559249423Sdim CheckLifetime, BlacklistFile, ZeroBaseShadow); 560234285Sdim} 561234285Sdim 562249423Sdimchar AddressSanitizerModule::ID = 0; 563249423SdimINITIALIZE_PASS(AddressSanitizerModule, "asan-module", 564249423Sdim "AddressSanitizer: detects use-after-free and out-of-bounds bugs." 565249423Sdim "ModulePass", false, false) 566249423SdimModulePass *llvm::createAddressSanitizerModulePass( 567249423Sdim bool CheckInitOrder, StringRef BlacklistFile, bool ZeroBaseShadow) { 568249423Sdim return new AddressSanitizerModule(CheckInitOrder, BlacklistFile, 569249423Sdim ZeroBaseShadow); 570234285Sdim} 571234285Sdim 572239462Sdimstatic size_t TypeSizeToSizeIndex(uint32_t TypeSize) { 573263508Sdim size_t Res = countTrailingZeros(TypeSize / 8); 574239462Sdim assert(Res < kNumberOfAccessSizes); 575239462Sdim return Res; 576239462Sdim} 577239462Sdim 578263508Sdim// \brief Create a constant for Str so that we can pass it to the run-time lib. 579234285Sdimstatic GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) { 580234285Sdim Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str); 581249423Sdim GlobalVariable *GV = new GlobalVariable(M, StrConst->getType(), true, 582263508Sdim GlobalValue::InternalLinkage, StrConst, 583249423Sdim kAsanGenPrefix); 584249423Sdim GV->setUnnamedAddr(true); // Ok to merge these. 585249423Sdim GV->setAlignment(1); // Strings may not be merged w/o setting align 1. 586249423Sdim return GV; 587234285Sdim} 588234285Sdim 589249423Sdimstatic bool GlobalWasGeneratedByAsan(GlobalVariable *G) { 590249423Sdim return G->getName().find(kAsanGenPrefix) == 0; 591249423Sdim} 592249423Sdim 593234285SdimValue *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) { 594234285Sdim // Shadow >> scale 595249423Sdim Shadow = IRB.CreateLShr(Shadow, Mapping.Scale); 596249423Sdim if (Mapping.Offset == 0) 597234285Sdim return Shadow; 598234285Sdim // (Shadow >> scale) | offset 599249423Sdim if (Mapping.OrShadowOffset) 600249423Sdim return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset)); 601249423Sdim else 602249423Sdim return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset)); 603234285Sdim} 604234285Sdim 605239462Sdimvoid AddressSanitizer::instrumentMemIntrinsicParam( 606243830Sdim Instruction *OrigIns, 607234285Sdim Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) { 608249423Sdim IRBuilder<> IRB(InsertBefore); 609249423Sdim if (Size->getType() != IntptrTy) 610249423Sdim Size = IRB.CreateIntCast(Size, IntptrTy, false); 611234285Sdim // Check the first byte. 612249423Sdim instrumentAddress(OrigIns, InsertBefore, Addr, 8, IsWrite, Size); 613234285Sdim // Check the last byte. 614249423Sdim IRB.SetInsertPoint(InsertBefore); 615249423Sdim Value *SizeMinusOne = IRB.CreateSub(Size, ConstantInt::get(IntptrTy, 1)); 616249423Sdim Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy); 617249423Sdim Value *AddrLast = IRB.CreateAdd(AddrLong, SizeMinusOne); 618249423Sdim instrumentAddress(OrigIns, InsertBefore, AddrLast, 8, IsWrite, Size); 619234285Sdim} 620234285Sdim 621234285Sdim// Instrument memset/memmove/memcpy 622243830Sdimbool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) { 623234285Sdim Value *Dst = MI->getDest(); 624234285Sdim MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI); 625239462Sdim Value *Src = MemTran ? MemTran->getSource() : 0; 626234285Sdim Value *Length = MI->getLength(); 627234285Sdim 628234285Sdim Constant *ConstLength = dyn_cast<Constant>(Length); 629234285Sdim Instruction *InsertBefore = MI; 630234285Sdim if (ConstLength) { 631234285Sdim if (ConstLength->isNullValue()) return false; 632234285Sdim } else { 633234285Sdim // The size is not a constant so it could be zero -- check at run-time. 634234285Sdim IRBuilder<> IRB(InsertBefore); 635234285Sdim 636234285Sdim Value *Cmp = IRB.CreateICmpNE(Length, 637239462Sdim Constant::getNullValue(Length->getType())); 638243830Sdim InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false); 639234285Sdim } 640234285Sdim 641243830Sdim instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true); 642234285Sdim if (Src) 643243830Sdim instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false); 644234285Sdim return true; 645234285Sdim} 646234285Sdim 647239462Sdim// If I is an interesting memory access, return the PointerOperand 648239462Sdim// and set IsWrite. Otherwise return NULL. 649239462Sdimstatic Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) { 650234285Sdim if (LoadInst *LI = dyn_cast<LoadInst>(I)) { 651239462Sdim if (!ClInstrumentReads) return NULL; 652239462Sdim *IsWrite = false; 653234285Sdim return LI->getPointerOperand(); 654234285Sdim } 655239462Sdim if (StoreInst *SI = dyn_cast<StoreInst>(I)) { 656239462Sdim if (!ClInstrumentWrites) return NULL; 657239462Sdim *IsWrite = true; 658239462Sdim return SI->getPointerOperand(); 659239462Sdim } 660239462Sdim if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) { 661239462Sdim if (!ClInstrumentAtomics) return NULL; 662239462Sdim *IsWrite = true; 663239462Sdim return RMW->getPointerOperand(); 664239462Sdim } 665239462Sdim if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) { 666239462Sdim if (!ClInstrumentAtomics) return NULL; 667239462Sdim *IsWrite = true; 668239462Sdim return XCHG->getPointerOperand(); 669239462Sdim } 670239462Sdim return NULL; 671234285Sdim} 672234285Sdim 673263508Sdimbool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) { 674263508Sdim // If a global variable does not have dynamic initialization we don't 675263508Sdim // have to instrument it. However, if a global does not have initializer 676263508Sdim // at all, we assume it has dynamic initializer (in other TU). 677263508Sdim return G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G); 678263508Sdim} 679263508Sdim 680243830Sdimvoid AddressSanitizer::instrumentMop(Instruction *I) { 681243830Sdim bool IsWrite = false; 682239462Sdim Value *Addr = isInterestingMemoryAccess(I, &IsWrite); 683239462Sdim assert(Addr); 684243830Sdim if (ClOpt && ClOptGlobals) { 685243830Sdim if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) { 686243830Sdim // If initialization order checking is disabled, a simple access to a 687243830Sdim // dynamically initialized global is always valid. 688263508Sdim if (!CheckInitOrder || GlobalIsLinkerInitialized(G)) { 689263508Sdim NumOptimizedAccessesToGlobalVar++; 690243830Sdim return; 691263508Sdim } 692243830Sdim } 693263508Sdim ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr); 694263508Sdim if (CE && CE->isGEPWithNoNotionalOverIndexing()) { 695263508Sdim if (GlobalVariable *G = dyn_cast<GlobalVariable>(CE->getOperand(0))) { 696263508Sdim if (CE->getOperand(1)->isNullValue() && GlobalIsLinkerInitialized(G)) { 697263508Sdim NumOptimizedAccessesToGlobalArray++; 698263508Sdim return; 699263508Sdim } 700263508Sdim } 701263508Sdim } 702234285Sdim } 703243830Sdim 704234285Sdim Type *OrigPtrTy = Addr->getType(); 705234285Sdim Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType(); 706234285Sdim 707234285Sdim assert(OrigTy->isSized()); 708234285Sdim uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy); 709234285Sdim 710249423Sdim assert((TypeSize % 8) == 0); 711234285Sdim 712263508Sdim if (IsWrite) 713263508Sdim NumInstrumentedWrites++; 714263508Sdim else 715263508Sdim NumInstrumentedReads++; 716263508Sdim 717249423Sdim // Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check. 718249423Sdim if (TypeSize == 8 || TypeSize == 16 || 719249423Sdim TypeSize == 32 || TypeSize == 64 || TypeSize == 128) 720249423Sdim return instrumentAddress(I, I, Addr, TypeSize, IsWrite, 0); 721249423Sdim // Instrument unusual size (but still multiple of 8). 722249423Sdim // We can not do it with a single check, so we do 1-byte check for the first 723249423Sdim // and the last bytes. We call __asan_report_*_n(addr, real_size) to be able 724249423Sdim // to report the actual access size. 725234285Sdim IRBuilder<> IRB(I); 726249423Sdim Value *LastByte = IRB.CreateIntToPtr( 727249423Sdim IRB.CreateAdd(IRB.CreatePointerCast(Addr, IntptrTy), 728249423Sdim ConstantInt::get(IntptrTy, TypeSize / 8 - 1)), 729249423Sdim OrigPtrTy); 730249423Sdim Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8); 731249423Sdim instrumentAddress(I, I, Addr, 8, IsWrite, Size); 732249423Sdim instrumentAddress(I, I, LastByte, 8, IsWrite, Size); 733234285Sdim} 734234285Sdim 735239462Sdim// Validate the result of Module::getOrInsertFunction called for an interface 736239462Sdim// function of AddressSanitizer. If the instrumented module defines a function 737239462Sdim// with the same name, their prototypes must match, otherwise 738239462Sdim// getOrInsertFunction returns a bitcast. 739249423Sdimstatic Function *checkInterfaceFunction(Constant *FuncOrBitcast) { 740239462Sdim if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast); 741239462Sdim FuncOrBitcast->dump(); 742239462Sdim report_fatal_error("trying to redefine an AddressSanitizer " 743239462Sdim "interface function"); 744239462Sdim} 745239462Sdim 746234285SdimInstruction *AddressSanitizer::generateCrashCode( 747239462Sdim Instruction *InsertBefore, Value *Addr, 748249423Sdim bool IsWrite, size_t AccessSizeIndex, Value *SizeArgument) { 749239462Sdim IRBuilder<> IRB(InsertBefore); 750249423Sdim CallInst *Call = SizeArgument 751249423Sdim ? IRB.CreateCall2(AsanErrorCallbackSized[IsWrite], Addr, SizeArgument) 752249423Sdim : IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr); 753249423Sdim 754239462Sdim // We don't do Call->setDoesNotReturn() because the BB already has 755239462Sdim // UnreachableInst at the end. 756239462Sdim // This EmptyAsm is required to avoid callback merge. 757239462Sdim IRB.CreateCall(EmptyAsm); 758234285Sdim return Call; 759234285Sdim} 760234285Sdim 761239462SdimValue *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong, 762239462Sdim Value *ShadowValue, 763239462Sdim uint32_t TypeSize) { 764249423Sdim size_t Granularity = 1 << Mapping.Scale; 765239462Sdim // Addr & (Granularity - 1) 766239462Sdim Value *LastAccessedByte = IRB.CreateAnd( 767239462Sdim AddrLong, ConstantInt::get(IntptrTy, Granularity - 1)); 768239462Sdim // (Addr & (Granularity - 1)) + size - 1 769239462Sdim if (TypeSize / 8 > 1) 770239462Sdim LastAccessedByte = IRB.CreateAdd( 771239462Sdim LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)); 772239462Sdim // (uint8_t) ((Addr & (Granularity-1)) + size - 1) 773239462Sdim LastAccessedByte = IRB.CreateIntCast( 774239462Sdim LastAccessedByte, ShadowValue->getType(), false); 775239462Sdim // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue 776239462Sdim return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue); 777239462Sdim} 778239462Sdim 779243830Sdimvoid AddressSanitizer::instrumentAddress(Instruction *OrigIns, 780249423Sdim Instruction *InsertBefore, 781249423Sdim Value *Addr, uint32_t TypeSize, 782249423Sdim bool IsWrite, Value *SizeArgument) { 783249423Sdim IRBuilder<> IRB(InsertBefore); 784234285Sdim Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy); 785234285Sdim 786234285Sdim Type *ShadowTy = IntegerType::get( 787249423Sdim *C, std::max(8U, TypeSize >> Mapping.Scale)); 788234285Sdim Type *ShadowPtrTy = PointerType::get(ShadowTy, 0); 789234285Sdim Value *ShadowPtr = memToShadow(AddrLong, IRB); 790234285Sdim Value *CmpVal = Constant::getNullValue(ShadowTy); 791234285Sdim Value *ShadowValue = IRB.CreateLoad( 792234285Sdim IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy)); 793234285Sdim 794234285Sdim Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal); 795239462Sdim size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize); 796249423Sdim size_t Granularity = 1 << Mapping.Scale; 797239462Sdim TerminatorInst *CrashTerm = 0; 798234285Sdim 799239462Sdim if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) { 800243830Sdim TerminatorInst *CheckTerm = 801243830Sdim SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false); 802239462Sdim assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional()); 803239462Sdim BasicBlock *NextBB = CheckTerm->getSuccessor(0); 804239462Sdim IRB.SetInsertPoint(CheckTerm); 805239462Sdim Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize); 806243830Sdim BasicBlock *CrashBlock = 807243830Sdim BasicBlock::Create(*C, "", NextBB->getParent(), NextBB); 808239462Sdim CrashTerm = new UnreachableInst(*C, CrashBlock); 809239462Sdim BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2); 810239462Sdim ReplaceInstWithInst(CheckTerm, NewTerm); 811239462Sdim } else { 812243830Sdim CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true); 813234285Sdim } 814234285Sdim 815249423Sdim Instruction *Crash = generateCrashCode( 816249423Sdim CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument); 817234285Sdim Crash->setDebugLoc(OrigIns->getDebugLoc()); 818234285Sdim} 819234285Sdim 820249423Sdimvoid AddressSanitizerModule::createInitializerPoisonCalls( 821249423Sdim Module &M, GlobalValue *ModuleName) { 822243830Sdim // We do all of our poisoning and unpoisoning within _GLOBAL__I_a. 823243830Sdim Function *GlobalInit = M.getFunction("_GLOBAL__I_a"); 824243830Sdim // If that function is not present, this TU contains no globals, or they have 825243830Sdim // all been optimized away 826243830Sdim if (!GlobalInit) 827243830Sdim return; 828234285Sdim 829243830Sdim // Set up the arguments to our poison/unpoison functions. 830243830Sdim IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt()); 831234285Sdim 832243830Sdim // Add a call to poison all external globals before the given function starts. 833249423Sdim Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy); 834249423Sdim IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr); 835243830Sdim 836243830Sdim // Add calls to unpoison all globals before each return instruction. 837243830Sdim for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end(); 838243830Sdim I != E; ++I) { 839243830Sdim if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) { 840243830Sdim CallInst::Create(AsanUnpoisonGlobals, "", RI); 841234285Sdim } 842243830Sdim } 843243830Sdim} 844234285Sdim 845249423Sdimbool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) { 846243830Sdim Type *Ty = cast<PointerType>(G->getType())->getElementType(); 847243830Sdim DEBUG(dbgs() << "GLOBAL: " << *G << "\n"); 848243830Sdim 849243830Sdim if (BL->isIn(*G)) return false; 850243830Sdim if (!Ty->isSized()) return false; 851243830Sdim if (!G->hasInitializer()) return false; 852249423Sdim if (GlobalWasGeneratedByAsan(G)) return false; // Our own global. 853243830Sdim // Touch only those globals that will not be defined in other modules. 854243830Sdim // Don't handle ODR type linkages since other modules may be built w/o asan. 855243830Sdim if (G->getLinkage() != GlobalVariable::ExternalLinkage && 856243830Sdim G->getLinkage() != GlobalVariable::PrivateLinkage && 857243830Sdim G->getLinkage() != GlobalVariable::InternalLinkage) 858243830Sdim return false; 859243830Sdim // Two problems with thread-locals: 860243830Sdim // - The address of the main thread's copy can't be computed at link-time. 861243830Sdim // - Need to poison all copies, not just the main thread's one. 862243830Sdim if (G->isThreadLocal()) 863243830Sdim return false; 864243830Sdim // For now, just ignore this Alloca if the alignment is large. 865249423Sdim if (G->getAlignment() > RedzoneSize()) return false; 866243830Sdim 867243830Sdim // Ignore all the globals with the names starting with "\01L_OBJC_". 868243830Sdim // Many of those are put into the .cstring section. The linker compresses 869243830Sdim // that section by removing the spare \0s after the string terminator, so 870243830Sdim // our redzones get broken. 871243830Sdim if ((G->getName().find("\01L_OBJC_") == 0) || 872243830Sdim (G->getName().find("\01l_OBJC_") == 0)) { 873243830Sdim DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G); 874243830Sdim return false; 875243830Sdim } 876243830Sdim 877243830Sdim if (G->hasSection()) { 878243830Sdim StringRef Section(G->getSection()); 879243830Sdim // Ignore the globals from the __OBJC section. The ObjC runtime assumes 880243830Sdim // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to 881243830Sdim // them. 882243830Sdim if ((Section.find("__OBJC,") == 0) || 883243830Sdim (Section.find("__DATA, __objc_") == 0)) { 884243830Sdim DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G); 885243830Sdim return false; 886234285Sdim } 887243830Sdim // See http://code.google.com/p/address-sanitizer/issues/detail?id=32 888243830Sdim // Constant CFString instances are compiled in the following way: 889243830Sdim // -- the string buffer is emitted into 890243830Sdim // __TEXT,__cstring,cstring_literals 891243830Sdim // -- the constant NSConstantString structure referencing that buffer 892243830Sdim // is placed into __DATA,__cfstring 893243830Sdim // Therefore there's no point in placing redzones into __DATA,__cfstring. 894243830Sdim // Moreover, it causes the linker to crash on OS X 10.7 895243830Sdim if (Section.find("__DATA,__cfstring") == 0) { 896243830Sdim DEBUG(dbgs() << "Ignoring CFString: " << *G); 897243830Sdim return false; 898243830Sdim } 899243830Sdim } 900234285Sdim 901243830Sdim return true; 902243830Sdim} 903243830Sdim 904249423Sdimvoid AddressSanitizerModule::initializeCallbacks(Module &M) { 905249423Sdim IRBuilder<> IRB(*C); 906249423Sdim // Declare our poisoning and unpoisoning functions. 907249423Sdim AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction( 908249423Sdim kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL)); 909249423Sdim AsanPoisonGlobals->setLinkage(Function::ExternalLinkage); 910249423Sdim AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction( 911249423Sdim kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL)); 912249423Sdim AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage); 913249423Sdim // Declare functions that register/unregister globals. 914249423Sdim AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction( 915249423Sdim kAsanRegisterGlobalsName, IRB.getVoidTy(), 916249423Sdim IntptrTy, IntptrTy, NULL)); 917249423Sdim AsanRegisterGlobals->setLinkage(Function::ExternalLinkage); 918249423Sdim AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction( 919249423Sdim kAsanUnregisterGlobalsName, 920249423Sdim IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); 921249423Sdim AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage); 922249423Sdim} 923249423Sdim 924243830Sdim// This function replaces all global variables with new variables that have 925243830Sdim// trailing redzones. It also creates a function that poisons 926243830Sdim// redzones and inserts this function into llvm.global_ctors. 927249423Sdimbool AddressSanitizerModule::runOnModule(Module &M) { 928249423Sdim if (!ClGlobals) return false; 929249423Sdim TD = getAnalysisIfAvailable<DataLayout>(); 930249423Sdim if (!TD) 931249423Sdim return false; 932263508Sdim BL.reset(SpecialCaseList::createOrDie(BlacklistFile)); 933249423Sdim if (BL->isIn(M)) return false; 934249423Sdim C = &(M.getContext()); 935249423Sdim int LongSize = TD->getPointerSizeInBits(); 936249423Sdim IntptrTy = Type::getIntNTy(*C, LongSize); 937249423Sdim Mapping = getShadowMapping(M, LongSize, ZeroBaseShadow); 938249423Sdim initializeCallbacks(M); 939249423Sdim DynamicallyInitializedGlobals.Init(M); 940249423Sdim 941243830Sdim SmallVector<GlobalVariable *, 16> GlobalsToChange; 942243830Sdim 943243830Sdim for (Module::GlobalListType::iterator G = M.global_begin(), 944243830Sdim E = M.global_end(); G != E; ++G) { 945243830Sdim if (ShouldInstrumentGlobal(G)) 946243830Sdim GlobalsToChange.push_back(G); 947234285Sdim } 948234285Sdim 949234285Sdim size_t n = GlobalsToChange.size(); 950234285Sdim if (n == 0) return false; 951234285Sdim 952234285Sdim // A global is described by a structure 953234285Sdim // size_t beg; 954234285Sdim // size_t size; 955234285Sdim // size_t size_with_redzone; 956234285Sdim // const char *name; 957249423Sdim // const char *module_name; 958243830Sdim // size_t has_dynamic_init; 959234285Sdim // We initialize an array of such structures and pass it to a run-time call. 960234285Sdim StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy, 961243830Sdim IntptrTy, IntptrTy, 962249423Sdim IntptrTy, IntptrTy, NULL); 963263508Sdim SmallVector<Constant *, 16> Initializers(n); 964234285Sdim 965249423Sdim Function *CtorFunc = M.getFunction(kAsanModuleCtorName); 966249423Sdim assert(CtorFunc); 967249423Sdim IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator()); 968243830Sdim 969249423Sdim bool HasDynamicallyInitializedGlobals = false; 970243830Sdim 971249423Sdim GlobalVariable *ModuleName = createPrivateGlobalForString( 972249423Sdim M, M.getModuleIdentifier()); 973249423Sdim // We shouldn't merge same module names, as this string serves as unique 974249423Sdim // module ID in runtime. 975249423Sdim ModuleName->setUnnamedAddr(false); 976249423Sdim 977234285Sdim for (size_t i = 0; i < n; i++) { 978249423Sdim static const uint64_t kMaxGlobalRedzone = 1 << 18; 979234285Sdim GlobalVariable *G = GlobalsToChange[i]; 980234285Sdim PointerType *PtrTy = cast<PointerType>(G->getType()); 981234285Sdim Type *Ty = PtrTy->getElementType(); 982234285Sdim uint64_t SizeInBytes = TD->getTypeAllocSize(Ty); 983249423Sdim uint64_t MinRZ = RedzoneSize(); 984249423Sdim // MinRZ <= RZ <= kMaxGlobalRedzone 985249423Sdim // and trying to make RZ to be ~ 1/4 of SizeInBytes. 986249423Sdim uint64_t RZ = std::max(MinRZ, 987249423Sdim std::min(kMaxGlobalRedzone, 988249423Sdim (SizeInBytes / MinRZ / 4) * MinRZ)); 989249423Sdim uint64_t RightRedzoneSize = RZ; 990249423Sdim // Round up to MinRZ 991249423Sdim if (SizeInBytes % MinRZ) 992249423Sdim RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ); 993249423Sdim assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0); 994234285Sdim Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize); 995243830Sdim // Determine whether this global should be poisoned in initialization. 996249423Sdim bool GlobalHasDynamicInitializer = 997249423Sdim DynamicallyInitializedGlobals.Contains(G); 998243830Sdim // Don't check initialization order if this global is blacklisted. 999263508Sdim GlobalHasDynamicInitializer &= !BL->isIn(*G, "init"); 1000234285Sdim 1001234285Sdim StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL); 1002234285Sdim Constant *NewInitializer = ConstantStruct::get( 1003234285Sdim NewTy, G->getInitializer(), 1004234285Sdim Constant::getNullValue(RightRedZoneTy), NULL); 1005234285Sdim 1006249423Sdim GlobalVariable *Name = createPrivateGlobalForString(M, G->getName()); 1007234285Sdim 1008234285Sdim // Create a new global variable with enough space for a redzone. 1009263508Sdim GlobalValue::LinkageTypes Linkage = G->getLinkage(); 1010263508Sdim if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage) 1011263508Sdim Linkage = GlobalValue::InternalLinkage; 1012234285Sdim GlobalVariable *NewGlobal = new GlobalVariable( 1013263508Sdim M, NewTy, G->isConstant(), Linkage, 1014239462Sdim NewInitializer, "", G, G->getThreadLocalMode()); 1015234285Sdim NewGlobal->copyAttributesFrom(G); 1016249423Sdim NewGlobal->setAlignment(MinRZ); 1017234285Sdim 1018234285Sdim Value *Indices2[2]; 1019234285Sdim Indices2[0] = IRB.getInt32(0); 1020234285Sdim Indices2[1] = IRB.getInt32(0); 1021234285Sdim 1022234285Sdim G->replaceAllUsesWith( 1023234285Sdim ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true)); 1024234285Sdim NewGlobal->takeName(G); 1025234285Sdim G->eraseFromParent(); 1026234285Sdim 1027234285Sdim Initializers[i] = ConstantStruct::get( 1028234285Sdim GlobalStructTy, 1029234285Sdim ConstantExpr::getPointerCast(NewGlobal, IntptrTy), 1030234285Sdim ConstantInt::get(IntptrTy, SizeInBytes), 1031234285Sdim ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize), 1032234285Sdim ConstantExpr::getPointerCast(Name, IntptrTy), 1033249423Sdim ConstantExpr::getPointerCast(ModuleName, IntptrTy), 1034243830Sdim ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer), 1035234285Sdim NULL); 1036243830Sdim 1037243830Sdim // Populate the first and last globals declared in this TU. 1038249423Sdim if (CheckInitOrder && GlobalHasDynamicInitializer) 1039249423Sdim HasDynamicallyInitializedGlobals = true; 1040243830Sdim 1041243830Sdim DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n"); 1042234285Sdim } 1043234285Sdim 1044234285Sdim ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n); 1045234285Sdim GlobalVariable *AllGlobals = new GlobalVariable( 1046263508Sdim M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage, 1047234285Sdim ConstantArray::get(ArrayOfGlobalStructTy, Initializers), ""); 1048234285Sdim 1049243830Sdim // Create calls for poisoning before initializers run and unpoisoning after. 1050249423Sdim if (CheckInitOrder && HasDynamicallyInitializedGlobals) 1051249423Sdim createInitializerPoisonCalls(M, ModuleName); 1052234285Sdim IRB.CreateCall2(AsanRegisterGlobals, 1053234285Sdim IRB.CreatePointerCast(AllGlobals, IntptrTy), 1054234285Sdim ConstantInt::get(IntptrTy, n)); 1055234285Sdim 1056234285Sdim // We also need to unregister globals at the end, e.g. when a shared library 1057234285Sdim // gets closed. 1058234285Sdim Function *AsanDtorFunction = Function::Create( 1059234285Sdim FunctionType::get(Type::getVoidTy(*C), false), 1060234285Sdim GlobalValue::InternalLinkage, kAsanModuleDtorName, &M); 1061234285Sdim BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction); 1062234285Sdim IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB)); 1063234285Sdim IRB_Dtor.CreateCall2(AsanUnregisterGlobals, 1064234285Sdim IRB.CreatePointerCast(AllGlobals, IntptrTy), 1065234285Sdim ConstantInt::get(IntptrTy, n)); 1066234285Sdim appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority); 1067234285Sdim 1068234285Sdim DEBUG(dbgs() << M); 1069234285Sdim return true; 1070234285Sdim} 1071234285Sdim 1072249423Sdimvoid AddressSanitizer::initializeCallbacks(Module &M) { 1073249423Sdim IRBuilder<> IRB(*C); 1074239462Sdim // Create __asan_report* callbacks. 1075239462Sdim for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) { 1076239462Sdim for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes; 1077239462Sdim AccessSizeIndex++) { 1078239462Sdim // IsWrite and TypeSize are encoded in the function name. 1079239462Sdim std::string FunctionName = std::string(kAsanReportErrorTemplate) + 1080239462Sdim (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex); 1081239462Sdim // If we are merging crash callbacks, they have two parameters. 1082243830Sdim AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = 1083243830Sdim checkInterfaceFunction(M.getOrInsertFunction( 1084243830Sdim FunctionName, IRB.getVoidTy(), IntptrTy, NULL)); 1085239462Sdim } 1086239462Sdim } 1087249423Sdim AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction( 1088249423Sdim kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); 1089249423Sdim AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction( 1090249423Sdim kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); 1091243830Sdim 1092243830Sdim AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction( 1093243830Sdim kAsanHandleNoReturnName, IRB.getVoidTy(), NULL)); 1094263508Sdim AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction( 1095263508Sdim kAsanCovName, IRB.getVoidTy(), IntptrTy, NULL)); 1096239462Sdim // We insert an empty inline asm after __asan_report* to avoid callback merge. 1097239462Sdim EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false), 1098239462Sdim StringRef(""), StringRef(""), 1099239462Sdim /*hasSideEffects=*/true); 1100249423Sdim} 1101239462Sdim 1102249423Sdimvoid AddressSanitizer::emitShadowMapping(Module &M, IRBuilder<> &IRB) const { 1103249423Sdim // Tell the values of mapping offset and scale to the run-time. 1104249423Sdim GlobalValue *asan_mapping_offset = 1105249423Sdim new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage, 1106249423Sdim ConstantInt::get(IntptrTy, Mapping.Offset), 1107249423Sdim kAsanMappingOffsetName); 1108249423Sdim // Read the global, otherwise it may be optimized away. 1109249423Sdim IRB.CreateLoad(asan_mapping_offset, true); 1110239462Sdim 1111249423Sdim GlobalValue *asan_mapping_scale = 1112249423Sdim new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage, 1113249423Sdim ConstantInt::get(IntptrTy, Mapping.Scale), 1114249423Sdim kAsanMappingScaleName); 1115249423Sdim // Read the global, otherwise it may be optimized away. 1116249423Sdim IRB.CreateLoad(asan_mapping_scale, true); 1117249423Sdim} 1118234285Sdim 1119249423Sdim// virtual 1120249423Sdimbool AddressSanitizer::doInitialization(Module &M) { 1121249423Sdim // Initialize the private fields. No one has accessed them before. 1122249423Sdim TD = getAnalysisIfAvailable<DataLayout>(); 1123234285Sdim 1124249423Sdim if (!TD) 1125249423Sdim return false; 1126263508Sdim BL.reset(SpecialCaseList::createOrDie(BlacklistFile)); 1127249423Sdim DynamicallyInitializedGlobals.Init(M); 1128234285Sdim 1129249423Sdim C = &(M.getContext()); 1130249423Sdim LongSize = TD->getPointerSizeInBits(); 1131249423Sdim IntptrTy = Type::getIntNTy(*C, LongSize); 1132249423Sdim 1133249423Sdim AsanCtorFunction = Function::Create( 1134249423Sdim FunctionType::get(Type::getVoidTy(*C), false), 1135249423Sdim GlobalValue::InternalLinkage, kAsanModuleCtorName, &M); 1136249423Sdim BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction); 1137249423Sdim // call __asan_init in the module ctor. 1138249423Sdim IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB)); 1139249423Sdim AsanInitFunction = checkInterfaceFunction( 1140249423Sdim M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL)); 1141249423Sdim AsanInitFunction->setLinkage(Function::ExternalLinkage); 1142249423Sdim IRB.CreateCall(AsanInitFunction); 1143249423Sdim 1144249423Sdim Mapping = getShadowMapping(M, LongSize, ZeroBaseShadow); 1145249423Sdim emitShadowMapping(M, IRB); 1146249423Sdim 1147234285Sdim appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority); 1148243830Sdim return true; 1149234285Sdim} 1150234285Sdim 1151234285Sdimbool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) { 1152234285Sdim // For each NSObject descendant having a +load method, this method is invoked 1153234285Sdim // by the ObjC runtime before any of the static constructors is called. 1154234285Sdim // Therefore we need to instrument such methods with a call to __asan_init 1155234285Sdim // at the beginning in order to initialize our runtime before any access to 1156234285Sdim // the shadow memory. 1157234285Sdim // We cannot just ignore these methods, because they may call other 1158234285Sdim // instrumented functions. 1159234285Sdim if (F.getName().find(" load]") != std::string::npos) { 1160234285Sdim IRBuilder<> IRB(F.begin()->begin()); 1161234285Sdim IRB.CreateCall(AsanInitFunction); 1162234285Sdim return true; 1163234285Sdim } 1164234285Sdim return false; 1165234285Sdim} 1166234285Sdim 1167263508Sdim// Poor man's coverage that works with ASan. 1168263508Sdim// We create a Guard boolean variable with the same linkage 1169263508Sdim// as the function and inject this code into the entry block: 1170263508Sdim// if (*Guard) { 1171263508Sdim// __sanitizer_cov(&F); 1172263508Sdim// *Guard = 1; 1173263508Sdim// } 1174263508Sdim// The accesses to Guard are atomic. The rest of the logic is 1175263508Sdim// in __sanitizer_cov (it's fine to call it more than once). 1176263508Sdim// 1177263508Sdim// This coverage implementation provides very limited data: 1178263508Sdim// it only tells if a given function was ever executed. 1179263508Sdim// No counters, no per-basic-block or per-edge data. 1180263508Sdim// But for many use cases this is what we need and the added slowdown 1181263508Sdim// is negligible. This simple implementation will probably be obsoleted 1182263508Sdim// by the upcoming Clang-based coverage implementation. 1183263508Sdim// By having it here and now we hope to 1184263508Sdim// a) get the functionality to users earlier and 1185263508Sdim// b) collect usage statistics to help improve Clang coverage design. 1186263508Sdimbool AddressSanitizer::InjectCoverage(Function &F) { 1187263508Sdim if (!ClCoverage) return false; 1188263508Sdim IRBuilder<> IRB(F.getEntryBlock().getFirstInsertionPt()); 1189263508Sdim Type *Int8Ty = IRB.getInt8Ty(); 1190263508Sdim GlobalVariable *Guard = new GlobalVariable( 1191263508Sdim *F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage, 1192263508Sdim Constant::getNullValue(Int8Ty), "__asan_gen_cov_" + F.getName()); 1193263508Sdim LoadInst *Load = IRB.CreateLoad(Guard); 1194263508Sdim Load->setAtomic(Monotonic); 1195263508Sdim Load->setAlignment(1); 1196263508Sdim Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load); 1197263508Sdim Instruction *Ins = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false); 1198263508Sdim IRB.SetInsertPoint(Ins); 1199263508Sdim // We pass &F to __sanitizer_cov. We could avoid this and rely on 1200263508Sdim // GET_CALLER_PC, but having the PC of the first instruction is just nice. 1201263508Sdim IRB.CreateCall(AsanCovFunction, IRB.CreatePointerCast(&F, IntptrTy)); 1202263508Sdim StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard); 1203263508Sdim Store->setAtomic(Monotonic); 1204263508Sdim Store->setAlignment(1); 1205263508Sdim return true; 1206263508Sdim} 1207263508Sdim 1208243830Sdimbool AddressSanitizer::runOnFunction(Function &F) { 1209234285Sdim if (BL->isIn(F)) return false; 1210234285Sdim if (&F == AsanCtorFunction) return false; 1211249423Sdim if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false; 1212243830Sdim DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n"); 1213249423Sdim initializeCallbacks(*F.getParent()); 1214234285Sdim 1215249423Sdim // If needed, insert __asan_init before checking for SanitizeAddress attr. 1216234285Sdim maybeInsertAsanInitAtFunctionEntry(F); 1217234285Sdim 1218263508Sdim if (!F.hasFnAttribute(Attribute::SanitizeAddress)) 1219243830Sdim return false; 1220234285Sdim 1221234285Sdim if (!ClDebugFunc.empty() && ClDebugFunc != F.getName()) 1222234285Sdim return false; 1223243830Sdim 1224243830Sdim // We want to instrument every address only once per basic block (unless there 1225243830Sdim // are calls between uses). 1226234285Sdim SmallSet<Value*, 16> TempsToInstrument; 1227234285Sdim SmallVector<Instruction*, 16> ToInstrument; 1228234285Sdim SmallVector<Instruction*, 8> NoReturnCalls; 1229263508Sdim int NumAllocas = 0; 1230239462Sdim bool IsWrite; 1231234285Sdim 1232234285Sdim // Fill the set of memory operations to instrument. 1233234285Sdim for (Function::iterator FI = F.begin(), FE = F.end(); 1234234285Sdim FI != FE; ++FI) { 1235234285Sdim TempsToInstrument.clear(); 1236239462Sdim int NumInsnsPerBB = 0; 1237234285Sdim for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); 1238234285Sdim BI != BE; ++BI) { 1239234285Sdim if (LooksLikeCodeInBug11395(BI)) return false; 1240239462Sdim if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) { 1241234285Sdim if (ClOpt && ClOptSameTemp) { 1242234285Sdim if (!TempsToInstrument.insert(Addr)) 1243234285Sdim continue; // We've seen this temp in the current BB. 1244234285Sdim } 1245234285Sdim } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) { 1246234285Sdim // ok, take it. 1247234285Sdim } else { 1248263508Sdim if (isa<AllocaInst>(BI)) 1249263508Sdim NumAllocas++; 1250249423Sdim CallSite CS(BI); 1251249423Sdim if (CS) { 1252234285Sdim // A call inside BB. 1253234285Sdim TempsToInstrument.clear(); 1254249423Sdim if (CS.doesNotReturn()) 1255249423Sdim NoReturnCalls.push_back(CS.getInstruction()); 1256234285Sdim } 1257234285Sdim continue; 1258234285Sdim } 1259234285Sdim ToInstrument.push_back(BI); 1260239462Sdim NumInsnsPerBB++; 1261239462Sdim if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) 1262239462Sdim break; 1263234285Sdim } 1264234285Sdim } 1265234285Sdim 1266263508Sdim Function *UninstrumentedDuplicate = 0; 1267263508Sdim bool LikelyToInstrument = 1268263508Sdim !NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0); 1269263508Sdim if (ClKeepUninstrumented && LikelyToInstrument) { 1270263508Sdim ValueToValueMapTy VMap; 1271263508Sdim UninstrumentedDuplicate = CloneFunction(&F, VMap, false); 1272263508Sdim UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress); 1273263508Sdim UninstrumentedDuplicate->setName("NOASAN_" + F.getName()); 1274263508Sdim F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate); 1275263508Sdim } 1276263508Sdim 1277234285Sdim // Instrument. 1278234285Sdim int NumInstrumented = 0; 1279234285Sdim for (size_t i = 0, n = ToInstrument.size(); i != n; i++) { 1280234285Sdim Instruction *Inst = ToInstrument[i]; 1281234285Sdim if (ClDebugMin < 0 || ClDebugMax < 0 || 1282234285Sdim (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) { 1283239462Sdim if (isInterestingMemoryAccess(Inst, &IsWrite)) 1284243830Sdim instrumentMop(Inst); 1285234285Sdim else 1286243830Sdim instrumentMemIntrinsic(cast<MemIntrinsic>(Inst)); 1287234285Sdim } 1288234285Sdim NumInstrumented++; 1289234285Sdim } 1290234285Sdim 1291249423Sdim FunctionStackPoisoner FSP(F, *this); 1292249423Sdim bool ChangedStack = FSP.runOnFunction(); 1293234285Sdim 1294234285Sdim // We must unpoison the stack before every NoReturn call (throw, _exit, etc). 1295234285Sdim // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37 1296234285Sdim for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) { 1297234285Sdim Instruction *CI = NoReturnCalls[i]; 1298234285Sdim IRBuilder<> IRB(CI); 1299243830Sdim IRB.CreateCall(AsanHandleNoReturnFunc); 1300234285Sdim } 1301234285Sdim 1302263508Sdim bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty(); 1303263508Sdim 1304263508Sdim if (InjectCoverage(F)) 1305263508Sdim res = true; 1306263508Sdim 1307263508Sdim DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n"); 1308263508Sdim 1309263508Sdim if (ClKeepUninstrumented) { 1310263508Sdim if (!res) { 1311263508Sdim // No instrumentation is done, no need for the duplicate. 1312263508Sdim if (UninstrumentedDuplicate) 1313263508Sdim UninstrumentedDuplicate->eraseFromParent(); 1314263508Sdim } else { 1315263508Sdim // The function was instrumented. We must have the duplicate. 1316263508Sdim assert(UninstrumentedDuplicate); 1317263508Sdim UninstrumentedDuplicate->setSection("NOASAN"); 1318263508Sdim assert(!F.hasSection()); 1319263508Sdim F.setSection("ASAN"); 1320263508Sdim } 1321263508Sdim } 1322263508Sdim 1323263508Sdim return res; 1324234285Sdim} 1325234285Sdim 1326234285Sdimstatic uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) { 1327234285Sdim if (ShadowRedzoneSize == 1) return PoisonByte; 1328234285Sdim if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte; 1329234285Sdim if (ShadowRedzoneSize == 4) 1330234285Sdim return (PoisonByte << 24) + (PoisonByte << 16) + 1331234285Sdim (PoisonByte << 8) + (PoisonByte); 1332234285Sdim llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4"); 1333234285Sdim} 1334234285Sdim 1335234285Sdimstatic void PoisonShadowPartialRightRedzone(uint8_t *Shadow, 1336234285Sdim size_t Size, 1337249423Sdim size_t RZSize, 1338234285Sdim size_t ShadowGranularity, 1339234285Sdim uint8_t Magic) { 1340249423Sdim for (size_t i = 0; i < RZSize; 1341234285Sdim i+= ShadowGranularity, Shadow++) { 1342234285Sdim if (i + ShadowGranularity <= Size) { 1343234285Sdim *Shadow = 0; // fully addressable 1344234285Sdim } else if (i >= Size) { 1345234285Sdim *Shadow = Magic; // unaddressable 1346234285Sdim } else { 1347234285Sdim *Shadow = Size - i; // first Size-i bytes are addressable 1348234285Sdim } 1349234285Sdim } 1350234285Sdim} 1351234285Sdim 1352249423Sdim// Workaround for bug 11395: we don't want to instrument stack in functions 1353249423Sdim// with large assembly blobs (32-bit only), otherwise reg alloc may crash. 1354249423Sdim// FIXME: remove once the bug 11395 is fixed. 1355249423Sdimbool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) { 1356249423Sdim if (LongSize != 32) return false; 1357249423Sdim CallInst *CI = dyn_cast<CallInst>(I); 1358249423Sdim if (!CI || !CI->isInlineAsm()) return false; 1359249423Sdim if (CI->getNumArgOperands() <= 5) return false; 1360249423Sdim // We have inline assembly with quite a few arguments. 1361249423Sdim return true; 1362249423Sdim} 1363249423Sdim 1364249423Sdimvoid FunctionStackPoisoner::initializeCallbacks(Module &M) { 1365249423Sdim IRBuilder<> IRB(*C); 1366263508Sdim for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) { 1367263508Sdim std::string Suffix = itostr(i); 1368263508Sdim AsanStackMallocFunc[i] = checkInterfaceFunction( 1369263508Sdim M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy, 1370263508Sdim IntptrTy, IntptrTy, NULL)); 1371263508Sdim AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction( 1372263508Sdim kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy, 1373263508Sdim IntptrTy, IntptrTy, NULL)); 1374263508Sdim } 1375249423Sdim AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction( 1376249423Sdim kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); 1377249423Sdim AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction( 1378249423Sdim kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL)); 1379249423Sdim} 1380249423Sdim 1381249423Sdimvoid FunctionStackPoisoner::poisonRedZones( 1382263508Sdim const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> &IRB, Value *ShadowBase, 1383249423Sdim bool DoPoison) { 1384249423Sdim size_t ShadowRZSize = RedzoneSize() >> Mapping.Scale; 1385234285Sdim assert(ShadowRZSize >= 1 && ShadowRZSize <= 4); 1386234285Sdim Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8); 1387234285Sdim Type *RZPtrTy = PointerType::get(RZTy, 0); 1388234285Sdim 1389234285Sdim Value *PoisonLeft = ConstantInt::get(RZTy, 1390234285Sdim ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize)); 1391234285Sdim Value *PoisonMid = ConstantInt::get(RZTy, 1392234285Sdim ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize)); 1393234285Sdim Value *PoisonRight = ConstantInt::get(RZTy, 1394234285Sdim ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize)); 1395234285Sdim 1396234285Sdim // poison the first red zone. 1397234285Sdim IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy)); 1398234285Sdim 1399234285Sdim // poison all other red zones. 1400249423Sdim uint64_t Pos = RedzoneSize(); 1401234285Sdim for (size_t i = 0, n = AllocaVec.size(); i < n; i++) { 1402234285Sdim AllocaInst *AI = AllocaVec[i]; 1403234285Sdim uint64_t SizeInBytes = getAllocaSizeInBytes(AI); 1404234285Sdim uint64_t AlignedSize = getAlignedAllocaSize(AI); 1405249423Sdim assert(AlignedSize - SizeInBytes < RedzoneSize()); 1406234285Sdim Value *Ptr = NULL; 1407234285Sdim 1408234285Sdim Pos += AlignedSize; 1409234285Sdim 1410234285Sdim assert(ShadowBase->getType() == IntptrTy); 1411234285Sdim if (SizeInBytes < AlignedSize) { 1412234285Sdim // Poison the partial redzone at right 1413234285Sdim Ptr = IRB.CreateAdd( 1414234285Sdim ShadowBase, ConstantInt::get(IntptrTy, 1415249423Sdim (Pos >> Mapping.Scale) - ShadowRZSize)); 1416249423Sdim size_t AddressableBytes = RedzoneSize() - (AlignedSize - SizeInBytes); 1417234285Sdim uint32_t Poison = 0; 1418234285Sdim if (DoPoison) { 1419234285Sdim PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes, 1420249423Sdim RedzoneSize(), 1421249423Sdim 1ULL << Mapping.Scale, 1422234285Sdim kAsanStackPartialRedzoneMagic); 1423263508Sdim Poison = 1424263508Sdim ASan.TD->isLittleEndian() 1425263508Sdim ? support::endian::byte_swap<uint32_t, support::little>(Poison) 1426263508Sdim : support::endian::byte_swap<uint32_t, support::big>(Poison); 1427234285Sdim } 1428234285Sdim Value *PartialPoison = ConstantInt::get(RZTy, Poison); 1429234285Sdim IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy)); 1430234285Sdim } 1431234285Sdim 1432234285Sdim // Poison the full redzone at right. 1433234285Sdim Ptr = IRB.CreateAdd(ShadowBase, 1434249423Sdim ConstantInt::get(IntptrTy, Pos >> Mapping.Scale)); 1435249423Sdim bool LastAlloca = (i == AllocaVec.size() - 1); 1436249423Sdim Value *Poison = LastAlloca ? PoisonRight : PoisonMid; 1437234285Sdim IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy)); 1438234285Sdim 1439249423Sdim Pos += RedzoneSize(); 1440234285Sdim } 1441234285Sdim} 1442234285Sdim 1443263508Sdim// Fake stack allocator (asan_fake_stack.h) has 11 size classes 1444263508Sdim// for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass 1445263508Sdimstatic int StackMallocSizeClass(uint64_t LocalStackSize) { 1446263508Sdim assert(LocalStackSize <= kMaxStackMallocSize); 1447263508Sdim uint64_t MaxSize = kMinStackMallocSize; 1448263508Sdim for (int i = 0; ; i++, MaxSize *= 2) 1449263508Sdim if (LocalStackSize <= MaxSize) 1450263508Sdim return i; 1451263508Sdim llvm_unreachable("impossible LocalStackSize"); 1452263508Sdim} 1453263508Sdim 1454263508Sdim// Set Size bytes starting from ShadowBase to kAsanStackAfterReturnMagic. 1455263508Sdim// We can not use MemSet intrinsic because it may end up calling the actual 1456263508Sdim// memset. Size is a multiple of 8. 1457263508Sdim// Currently this generates 8-byte stores on x86_64; it may be better to 1458263508Sdim// generate wider stores. 1459263508Sdimvoid FunctionStackPoisoner::SetShadowToStackAfterReturnInlined( 1460263508Sdim IRBuilder<> &IRB, Value *ShadowBase, int Size) { 1461263508Sdim assert(!(Size % 8)); 1462263508Sdim assert(kAsanStackAfterReturnMagic == 0xf5); 1463263508Sdim for (int i = 0; i < Size; i += 8) { 1464263508Sdim Value *p = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i)); 1465263508Sdim IRB.CreateStore(ConstantInt::get(IRB.getInt64Ty(), 0xf5f5f5f5f5f5f5f5ULL), 1466263508Sdim IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo())); 1467263508Sdim } 1468263508Sdim} 1469263508Sdim 1470249423Sdimvoid FunctionStackPoisoner::poisonStack() { 1471249423Sdim uint64_t LocalStackSize = TotalStackSize + 1472249423Sdim (AllocaVec.size() + 1) * RedzoneSize(); 1473234285Sdim 1474249423Sdim bool DoStackMalloc = ASan.CheckUseAfterReturn 1475234285Sdim && LocalStackSize <= kMaxStackMallocSize; 1476263508Sdim int StackMallocIdx = -1; 1477234285Sdim 1478249423Sdim assert(AllocaVec.size() > 0); 1479234285Sdim Instruction *InsBefore = AllocaVec[0]; 1480234285Sdim IRBuilder<> IRB(InsBefore); 1481234285Sdim 1482234285Sdim 1483234285Sdim Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize); 1484234285Sdim AllocaInst *MyAlloca = 1485234285Sdim new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore); 1486249423Sdim if (ClRealignStack && StackAlignment < RedzoneSize()) 1487249423Sdim StackAlignment = RedzoneSize(); 1488249423Sdim MyAlloca->setAlignment(StackAlignment); 1489234285Sdim assert(MyAlloca->isStaticAlloca()); 1490234285Sdim Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy); 1491234285Sdim Value *LocalStackBase = OrigStackBase; 1492234285Sdim 1493234285Sdim if (DoStackMalloc) { 1494263508Sdim // LocalStackBase = OrigStackBase 1495263508Sdim // if (__asan_option_detect_stack_use_after_return) 1496263508Sdim // LocalStackBase = __asan_stack_malloc_N(LocalStackBase, OrigStackBase); 1497263508Sdim StackMallocIdx = StackMallocSizeClass(LocalStackSize); 1498263508Sdim assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass); 1499263508Sdim Constant *OptionDetectUAR = F.getParent()->getOrInsertGlobal( 1500263508Sdim kAsanOptionDetectUAR, IRB.getInt32Ty()); 1501263508Sdim Value *Cmp = IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR), 1502263508Sdim Constant::getNullValue(IRB.getInt32Ty())); 1503263508Sdim Instruction *Term = 1504263508Sdim SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false); 1505263508Sdim BasicBlock *CmpBlock = cast<Instruction>(Cmp)->getParent(); 1506263508Sdim IRBuilder<> IRBIf(Term); 1507263508Sdim LocalStackBase = IRBIf.CreateCall2( 1508263508Sdim AsanStackMallocFunc[StackMallocIdx], 1509234285Sdim ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase); 1510263508Sdim BasicBlock *SetBlock = cast<Instruction>(LocalStackBase)->getParent(); 1511263508Sdim IRB.SetInsertPoint(InsBefore); 1512263508Sdim PHINode *Phi = IRB.CreatePHI(IntptrTy, 2); 1513263508Sdim Phi->addIncoming(OrigStackBase, CmpBlock); 1514263508Sdim Phi->addIncoming(LocalStackBase, SetBlock); 1515263508Sdim LocalStackBase = Phi; 1516234285Sdim } 1517234285Sdim 1518249423Sdim // This string will be parsed by the run-time (DescribeAddressIfStack). 1519234285Sdim SmallString<2048> StackDescriptionStorage; 1520234285Sdim raw_svector_ostream StackDescription(StackDescriptionStorage); 1521249423Sdim StackDescription << AllocaVec.size() << " "; 1522234285Sdim 1523249423Sdim // Insert poison calls for lifetime intrinsics for alloca. 1524249423Sdim bool HavePoisonedAllocas = false; 1525249423Sdim for (size_t i = 0, n = AllocaPoisonCallVec.size(); i < n; i++) { 1526249423Sdim const AllocaPoisonCall &APC = AllocaPoisonCallVec[i]; 1527263508Sdim assert(APC.InsBefore); 1528263508Sdim assert(APC.AI); 1529263508Sdim IRBuilder<> IRB(APC.InsBefore); 1530263508Sdim poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison); 1531249423Sdim HavePoisonedAllocas |= APC.DoPoison; 1532249423Sdim } 1533249423Sdim 1534249423Sdim uint64_t Pos = RedzoneSize(); 1535234285Sdim // Replace Alloca instructions with base+offset. 1536234285Sdim for (size_t i = 0, n = AllocaVec.size(); i < n; i++) { 1537234285Sdim AllocaInst *AI = AllocaVec[i]; 1538234285Sdim uint64_t SizeInBytes = getAllocaSizeInBytes(AI); 1539234285Sdim StringRef Name = AI->getName(); 1540234285Sdim StackDescription << Pos << " " << SizeInBytes << " " 1541234285Sdim << Name.size() << " " << Name << " "; 1542234285Sdim uint64_t AlignedSize = getAlignedAllocaSize(AI); 1543249423Sdim assert((AlignedSize % RedzoneSize()) == 0); 1544249423Sdim Value *NewAllocaPtr = IRB.CreateIntToPtr( 1545234285Sdim IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)), 1546249423Sdim AI->getType()); 1547249423Sdim replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB); 1548249423Sdim AI->replaceAllUsesWith(NewAllocaPtr); 1549249423Sdim Pos += AlignedSize + RedzoneSize(); 1550234285Sdim } 1551234285Sdim assert(Pos == LocalStackSize); 1552234285Sdim 1553249423Sdim // The left-most redzone has enough space for at least 4 pointers. 1554249423Sdim // Write the Magic value to redzone[0]. 1555234285Sdim Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy); 1556234285Sdim IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic), 1557234285Sdim BasePlus0); 1558249423Sdim // Write the frame description constant to redzone[1]. 1559249423Sdim Value *BasePlus1 = IRB.CreateIntToPtr( 1560249423Sdim IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)), 1561249423Sdim IntptrPtrTy); 1562243830Sdim GlobalVariable *StackDescriptionGlobal = 1563243830Sdim createPrivateGlobalForString(*F.getParent(), StackDescription.str()); 1564249423Sdim Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, 1565249423Sdim IntptrTy); 1566234285Sdim IRB.CreateStore(Description, BasePlus1); 1567249423Sdim // Write the PC to redzone[2]. 1568249423Sdim Value *BasePlus2 = IRB.CreateIntToPtr( 1569249423Sdim IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, 1570249423Sdim 2 * ASan.LongSize/8)), 1571249423Sdim IntptrPtrTy); 1572249423Sdim IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2); 1573234285Sdim 1574234285Sdim // Poison the stack redzones at the entry. 1575249423Sdim Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB); 1576249423Sdim poisonRedZones(AllocaVec, IRB, ShadowBase, true); 1577234285Sdim 1578234285Sdim // Unpoison the stack before all ret instructions. 1579234285Sdim for (size_t i = 0, n = RetVec.size(); i < n; i++) { 1580234285Sdim Instruction *Ret = RetVec[i]; 1581234285Sdim IRBuilder<> IRBRet(Ret); 1582234285Sdim // Mark the current frame as retired. 1583234285Sdim IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic), 1584234285Sdim BasePlus0); 1585234285Sdim // Unpoison the stack. 1586249423Sdim poisonRedZones(AllocaVec, IRBRet, ShadowBase, false); 1587234285Sdim if (DoStackMalloc) { 1588263508Sdim assert(StackMallocIdx >= 0); 1589249423Sdim // In use-after-return mode, mark the whole stack frame unaddressable. 1590263508Sdim if (StackMallocIdx <= 4) { 1591263508Sdim // For small sizes inline the whole thing: 1592263508Sdim // if LocalStackBase != OrigStackBase: 1593263508Sdim // memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize); 1594263508Sdim // **SavedFlagPtr(LocalStackBase) = 0 1595263508Sdim // FIXME: if LocalStackBase != OrigStackBase don't call poisonRedZones. 1596263508Sdim Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase); 1597263508Sdim TerminatorInst *PoisonTerm = 1598263508Sdim SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false); 1599263508Sdim IRBuilder<> IRBPoison(PoisonTerm); 1600263508Sdim int ClassSize = kMinStackMallocSize << StackMallocIdx; 1601263508Sdim SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase, 1602263508Sdim ClassSize >> Mapping.Scale); 1603263508Sdim Value *SavedFlagPtrPtr = IRBPoison.CreateAdd( 1604263508Sdim LocalStackBase, 1605263508Sdim ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8)); 1606263508Sdim Value *SavedFlagPtr = IRBPoison.CreateLoad( 1607263508Sdim IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy)); 1608263508Sdim IRBPoison.CreateStore( 1609263508Sdim Constant::getNullValue(IRBPoison.getInt8Ty()), 1610263508Sdim IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy())); 1611263508Sdim } else { 1612263508Sdim // For larger frames call __asan_stack_free_*. 1613263508Sdim IRBRet.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase, 1614263508Sdim ConstantInt::get(IntptrTy, LocalStackSize), 1615263508Sdim OrigStackBase); 1616263508Sdim } 1617249423Sdim } else if (HavePoisonedAllocas) { 1618249423Sdim // If we poisoned some allocas in llvm.lifetime analysis, 1619249423Sdim // unpoison whole stack frame now. 1620249423Sdim assert(LocalStackBase == OrigStackBase); 1621249423Sdim poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false); 1622234285Sdim } 1623234285Sdim } 1624234285Sdim 1625243830Sdim // We are done. Remove the old unused alloca instructions. 1626243830Sdim for (size_t i = 0, n = AllocaVec.size(); i < n; i++) 1627243830Sdim AllocaVec[i]->eraseFromParent(); 1628249423Sdim} 1629243830Sdim 1630249423Sdimvoid FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size, 1631263508Sdim IRBuilder<> &IRB, bool DoPoison) { 1632249423Sdim // For now just insert the call to ASan runtime. 1633249423Sdim Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy); 1634249423Sdim Value *SizeArg = ConstantInt::get(IntptrTy, Size); 1635249423Sdim IRB.CreateCall2(DoPoison ? AsanPoisonStackMemoryFunc 1636249423Sdim : AsanUnpoisonStackMemoryFunc, 1637249423Sdim AddrArg, SizeArg); 1638249423Sdim} 1639249423Sdim 1640249423Sdim// Handling llvm.lifetime intrinsics for a given %alloca: 1641249423Sdim// (1) collect all llvm.lifetime.xxx(%size, %value) describing the alloca. 1642249423Sdim// (2) if %size is constant, poison memory for llvm.lifetime.end (to detect 1643249423Sdim// invalid accesses) and unpoison it for llvm.lifetime.start (the memory 1644249423Sdim// could be poisoned by previous llvm.lifetime.end instruction, as the 1645249423Sdim// variable may go in and out of scope several times, e.g. in loops). 1646249423Sdim// (3) if we poisoned at least one %alloca in a function, 1647249423Sdim// unpoison the whole stack frame at function exit. 1648249423Sdim 1649249423SdimAllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) { 1650249423Sdim if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) 1651249423Sdim // We're intested only in allocas we can handle. 1652249423Sdim return isInterestingAlloca(*AI) ? AI : 0; 1653249423Sdim // See if we've already calculated (or started to calculate) alloca for a 1654249423Sdim // given value. 1655249423Sdim AllocaForValueMapTy::iterator I = AllocaForValue.find(V); 1656249423Sdim if (I != AllocaForValue.end()) 1657249423Sdim return I->second; 1658249423Sdim // Store 0 while we're calculating alloca for value V to avoid 1659249423Sdim // infinite recursion if the value references itself. 1660249423Sdim AllocaForValue[V] = 0; 1661249423Sdim AllocaInst *Res = 0; 1662249423Sdim if (CastInst *CI = dyn_cast<CastInst>(V)) 1663249423Sdim Res = findAllocaForValue(CI->getOperand(0)); 1664249423Sdim else if (PHINode *PN = dyn_cast<PHINode>(V)) { 1665249423Sdim for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { 1666249423Sdim Value *IncValue = PN->getIncomingValue(i); 1667249423Sdim // Allow self-referencing phi-nodes. 1668249423Sdim if (IncValue == PN) continue; 1669249423Sdim AllocaInst *IncValueAI = findAllocaForValue(IncValue); 1670249423Sdim // AI for incoming values should exist and should all be equal. 1671249423Sdim if (IncValueAI == 0 || (Res != 0 && IncValueAI != Res)) 1672249423Sdim return 0; 1673249423Sdim Res = IncValueAI; 1674249423Sdim } 1675234285Sdim } 1676249423Sdim if (Res != 0) 1677249423Sdim AllocaForValue[V] = Res; 1678249423Sdim return Res; 1679234285Sdim} 1680