1 //===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 // Details of the algorithm:
12 // http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
14 //===----------------------------------------------------------------------===//
16 #define DEBUG_TYPE "asan"
18 #include "BlackList.h"
19 #include "llvm/Function.h"
20 #include "llvm/IRBuilder.h"
21 #include "llvm/InlineAsm.h"
22 #include "llvm/IntrinsicInst.h"
23 #include "llvm/LLVMContext.h"
24 #include "llvm/Module.h"
25 #include "llvm/Type.h"
26 #include "llvm/ADT/ArrayRef.h"
27 #include "llvm/ADT/OwningPtr.h"
28 #include "llvm/ADT/SmallSet.h"
29 #include "llvm/ADT/SmallString.h"
30 #include "llvm/ADT/SmallVector.h"
31 #include "llvm/ADT/StringExtras.h"
32 #include "llvm/ADT/Triple.h"
33 #include "llvm/Support/CommandLine.h"
34 #include "llvm/Support/DataTypes.h"
35 #include "llvm/Support/Debug.h"
36 #include "llvm/Support/raw_ostream.h"
37 #include "llvm/Support/system_error.h"
38 #include "llvm/DataLayout.h"
39 #include "llvm/Target/TargetMachine.h"
40 #include "llvm/Transforms/Instrumentation.h"
41 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
42 #include "llvm/Transforms/Utils/ModuleUtils.h"
49 static const uint64_t kDefaultShadowScale = 3;
50 static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
51 static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
52 static const uint64_t kDefaultShadowOffsetAndroid = 0;
54 static const size_t kMaxStackMallocSize = 1 << 16; // 64K
55 static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
56 static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
58 static const char *kAsanModuleCtorName = "asan.module_ctor";
59 static const char *kAsanModuleDtorName = "asan.module_dtor";
60 static const int kAsanCtorAndCtorPriority = 1;
61 static const char *kAsanReportErrorTemplate = "__asan_report_";
62 static const char *kAsanRegisterGlobalsName = "__asan_register_globals";
63 static const char *kAsanUnregisterGlobalsName = "__asan_unregister_globals";
64 static const char *kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
65 static const char *kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
66 static const char *kAsanInitName = "__asan_init";
67 static const char *kAsanHandleNoReturnName = "__asan_handle_no_return";
68 static const char *kAsanMappingOffsetName = "__asan_mapping_offset";
69 static const char *kAsanMappingScaleName = "__asan_mapping_scale";
70 static const char *kAsanStackMallocName = "__asan_stack_malloc";
71 static const char *kAsanStackFreeName = "__asan_stack_free";
73 static const int kAsanStackLeftRedzoneMagic = 0xf1;
74 static const int kAsanStackMidRedzoneMagic = 0xf2;
75 static const int kAsanStackRightRedzoneMagic = 0xf3;
76 static const int kAsanStackPartialRedzoneMagic = 0xf4;
78 // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
79 static const size_t kNumberOfAccessSizes = 5;
81 // Command-line flags.
83 // This flag may need to be replaced with -f[no-]asan-reads.
84 static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
85 cl::desc("instrument read instructions"), cl::Hidden, cl::init(true));
86 static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
87 cl::desc("instrument write instructions"), cl::Hidden, cl::init(true));
88 static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
89 cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
90 cl::Hidden, cl::init(true));
91 static cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path",
92 cl::desc("use instrumentation with slow path for all accesses"),
93 cl::Hidden, cl::init(false));
94 // This flag limits the number of instructions to be instrumented
95 // in any given BB. Normally, this should be set to unlimited (INT_MAX),
96 // but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
98 static cl::opt<int> ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb",
100 cl::desc("maximal number of instructions to instrument in any given BB"),
102 // This flag may need to be replaced with -f[no]asan-stack.
103 static cl::opt<bool> ClStack("asan-stack",
104 cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
105 // This flag may need to be replaced with -f[no]asan-use-after-return.
106 static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
107 cl::desc("Check return-after-free"), cl::Hidden, cl::init(false));
108 // This flag may need to be replaced with -f[no]asan-globals.
109 static cl::opt<bool> ClGlobals("asan-globals",
110 cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
111 static cl::opt<bool> ClInitializers("asan-initialization-order",
112 cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false));
113 static cl::opt<bool> ClMemIntrin("asan-memintrin",
114 cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true));
115 // This flag may need to be replaced with -fasan-blacklist.
116 static cl::opt<std::string> ClBlackListFile("asan-blacklist",
117 cl::desc("File containing the list of functions to ignore "
118 "during instrumentation"), cl::Hidden);
120 // These flags allow to change the shadow mapping.
121 // The shadow mapping looks like
122 // Shadow = (Mem >> scale) + (1 << offset_log)
123 static cl::opt<int> ClMappingScale("asan-mapping-scale",
124 cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0));
125 static cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log",
126 cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1));
128 // Optimization flags. Not user visible, used mostly for testing
129 // and benchmarking the tool.
130 static cl::opt<bool> ClOpt("asan-opt",
131 cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true));
132 static cl::opt<bool> ClOptSameTemp("asan-opt-same-temp",
133 cl::desc("Instrument the same temp just once"), cl::Hidden,
135 static cl::opt<bool> ClOptGlobals("asan-opt-globals",
136 cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true));
139 static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
141 static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
142 cl::Hidden, cl::init(0));
143 static cl::opt<std::string> ClDebugFunc("asan-debug-func",
144 cl::Hidden, cl::desc("Debug func"));
145 static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
146 cl::Hidden, cl::init(-1));
147 static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
148 cl::Hidden, cl::init(-1));
151 /// AddressSanitizer: instrument the code in module to find memory bugs.
152 struct AddressSanitizer : public FunctionPass {
154 virtual const char *getPassName() const;
155 void instrumentMop(Instruction *I);
156 void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
157 Value *Addr, uint32_t TypeSize, bool IsWrite);
158 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
159 Value *ShadowValue, uint32_t TypeSize);
160 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
161 bool IsWrite, size_t AccessSizeIndex);
162 bool instrumentMemIntrinsic(MemIntrinsic *MI);
163 void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
165 Instruction *InsertBefore, bool IsWrite);
166 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
167 bool runOnFunction(Function &F);
168 void createInitializerPoisonCalls(Module &M,
169 Value *FirstAddr, Value *LastAddr);
170 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
171 bool poisonStackInFunction(Function &F);
172 virtual bool doInitialization(Module &M);
173 virtual bool doFinalization(Module &M);
174 bool insertGlobalRedzones(Module &M);
175 static char ID; // Pass identification, replacement for typeid
178 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
179 Type *Ty = AI->getAllocatedType();
180 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
183 uint64_t getAlignedSize(uint64_t SizeInBytes) {
184 return ((SizeInBytes + RedzoneSize - 1)
185 / RedzoneSize) * RedzoneSize;
187 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
188 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
189 return getAlignedSize(SizeInBytes);
192 Function *checkInterfaceFunction(Constant *FuncOrBitcast);
193 bool ShouldInstrumentGlobal(GlobalVariable *G);
194 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
195 Value *ShadowBase, bool DoPoison);
196 bool LooksLikeCodeInBug11395(Instruction *I);
197 void FindDynamicInitializers(Module &M);
198 bool HasDynamicInitializer(GlobalVariable *G);
202 uint64_t MappingOffset;
208 Function *AsanCtorFunction;
209 Function *AsanInitFunction;
210 Function *AsanStackMallocFunc, *AsanStackFreeFunc;
211 Function *AsanHandleNoReturnFunc;
212 Instruction *CtorInsertBefore;
213 OwningPtr<BlackList> BL;
214 // This array is indexed by AccessIsWrite and log2(AccessSize).
215 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
217 SmallSet<GlobalValue*, 32> DynamicallyInitializedGlobals;
222 char AddressSanitizer::ID = 0;
223 INITIALIZE_PASS(AddressSanitizer, "asan",
224 "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
226 AddressSanitizer::AddressSanitizer() : FunctionPass(ID) { }
227 FunctionPass *llvm::createAddressSanitizerPass() {
228 return new AddressSanitizer();
231 const char *AddressSanitizer::getPassName() const {
232 return "AddressSanitizer";
235 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
236 size_t Res = CountTrailingZeros_32(TypeSize / 8);
237 assert(Res < kNumberOfAccessSizes);
241 // Create a constant for Str so that we can pass it to the run-time lib.
242 static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
243 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
244 return new GlobalVariable(M, StrConst->getType(), true,
245 GlobalValue::PrivateLinkage, StrConst, "");
248 // Split the basic block and insert an if-then code.
259 // ThenBlock block is created and its terminator is returned.
260 // If Unreachable, ThenBlock is terminated with UnreachableInst, otherwise
261 // it is terminated with BranchInst to Tail.
262 static TerminatorInst *splitBlockAndInsertIfThen(Value *Cmp, bool Unreachable) {
263 Instruction *SplitBefore = cast<Instruction>(Cmp)->getNextNode();
264 BasicBlock *Head = SplitBefore->getParent();
265 BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
266 TerminatorInst *HeadOldTerm = Head->getTerminator();
267 LLVMContext &C = Head->getParent()->getParent()->getContext();
268 BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
269 TerminatorInst *CheckTerm;
271 CheckTerm = new UnreachableInst(C, ThenBlock);
273 CheckTerm = BranchInst::Create(Tail, ThenBlock);
274 BranchInst *HeadNewTerm =
275 BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
276 ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
280 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
282 Shadow = IRB.CreateLShr(Shadow, MappingScale);
283 if (MappingOffset == 0)
285 // (Shadow >> scale) | offset
286 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
290 void AddressSanitizer::instrumentMemIntrinsicParam(
291 Instruction *OrigIns,
292 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
293 // Check the first byte.
295 IRBuilder<> IRB(InsertBefore);
296 instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
298 // Check the last byte.
300 IRBuilder<> IRB(InsertBefore);
301 Value *SizeMinusOne = IRB.CreateSub(
302 Size, ConstantInt::get(Size->getType(), 1));
303 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
304 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
305 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
306 instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
310 // Instrument memset/memmove/memcpy
311 bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
312 Value *Dst = MI->getDest();
313 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
314 Value *Src = MemTran ? MemTran->getSource() : 0;
315 Value *Length = MI->getLength();
317 Constant *ConstLength = dyn_cast<Constant>(Length);
318 Instruction *InsertBefore = MI;
320 if (ConstLength->isNullValue()) return false;
322 // The size is not a constant so it could be zero -- check at run-time.
323 IRBuilder<> IRB(InsertBefore);
325 Value *Cmp = IRB.CreateICmpNE(Length,
326 Constant::getNullValue(Length->getType()));
327 InsertBefore = splitBlockAndInsertIfThen(Cmp, false);
330 instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
332 instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
336 // If I is an interesting memory access, return the PointerOperand
337 // and set IsWrite. Otherwise return NULL.
338 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
339 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
340 if (!ClInstrumentReads) return NULL;
342 return LI->getPointerOperand();
344 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
345 if (!ClInstrumentWrites) return NULL;
347 return SI->getPointerOperand();
349 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
350 if (!ClInstrumentAtomics) return NULL;
352 return RMW->getPointerOperand();
354 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
355 if (!ClInstrumentAtomics) return NULL;
357 return XCHG->getPointerOperand();
362 void AddressSanitizer::FindDynamicInitializers(Module& M) {
363 // Clang generates metadata identifying all dynamically initialized globals.
364 NamedMDNode *DynamicGlobals =
365 M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
368 for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
369 MDNode *MDN = DynamicGlobals->getOperand(i);
370 assert(MDN->getNumOperands() == 1);
371 Value *VG = MDN->getOperand(0);
372 // The optimizer may optimize away a global entirely, in which case we
373 // cannot instrument access to it.
377 GlobalVariable *G = cast<GlobalVariable>(VG);
378 DynamicallyInitializedGlobals.insert(G);
381 // Returns true if a global variable is initialized dynamically in this TU.
382 bool AddressSanitizer::HasDynamicInitializer(GlobalVariable *G) {
383 return DynamicallyInitializedGlobals.count(G);
386 void AddressSanitizer::instrumentMop(Instruction *I) {
387 bool IsWrite = false;
388 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
390 if (ClOpt && ClOptGlobals) {
391 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
392 // If initialization order checking is disabled, a simple access to a
393 // dynamically initialized global is always valid.
396 // If a global variable does not have dynamic initialization we don't
397 // have to instrument it. However, if a global has external linkage, we
398 // assume it has dynamic initialization, as it may have an initializer
399 // in a different TU.
400 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
401 !HasDynamicInitializer(G))
406 Type *OrigPtrTy = Addr->getType();
407 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
409 assert(OrigTy->isSized());
410 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
412 if (TypeSize != 8 && TypeSize != 16 &&
413 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
414 // Ignore all unusual sizes.
419 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
422 // Validate the result of Module::getOrInsertFunction called for an interface
423 // function of AddressSanitizer. If the instrumented module defines a function
424 // with the same name, their prototypes must match, otherwise
425 // getOrInsertFunction returns a bitcast.
426 Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
427 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
428 FuncOrBitcast->dump();
429 report_fatal_error("trying to redefine an AddressSanitizer "
430 "interface function");
433 Instruction *AddressSanitizer::generateCrashCode(
434 Instruction *InsertBefore, Value *Addr,
435 bool IsWrite, size_t AccessSizeIndex) {
436 IRBuilder<> IRB(InsertBefore);
437 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
439 // We don't do Call->setDoesNotReturn() because the BB already has
440 // UnreachableInst at the end.
441 // This EmptyAsm is required to avoid callback merge.
442 IRB.CreateCall(EmptyAsm);
446 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
449 size_t Granularity = 1 << MappingScale;
450 // Addr & (Granularity - 1)
451 Value *LastAccessedByte = IRB.CreateAnd(
452 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
453 // (Addr & (Granularity - 1)) + size - 1
454 if (TypeSize / 8 > 1)
455 LastAccessedByte = IRB.CreateAdd(
456 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
457 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
458 LastAccessedByte = IRB.CreateIntCast(
459 LastAccessedByte, ShadowValue->getType(), false);
460 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
461 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
464 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
465 IRBuilder<> &IRB, Value *Addr,
466 uint32_t TypeSize, bool IsWrite) {
467 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
469 Type *ShadowTy = IntegerType::get(
470 *C, std::max(8U, TypeSize >> MappingScale));
471 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
472 Value *ShadowPtr = memToShadow(AddrLong, IRB);
473 Value *CmpVal = Constant::getNullValue(ShadowTy);
474 Value *ShadowValue = IRB.CreateLoad(
475 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
477 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
478 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
479 size_t Granularity = 1 << MappingScale;
480 TerminatorInst *CrashTerm = 0;
482 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
483 TerminatorInst *CheckTerm = splitBlockAndInsertIfThen(Cmp, false);
484 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
485 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
486 IRB.SetInsertPoint(CheckTerm);
487 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
488 BasicBlock *CrashBlock =
489 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
490 CrashTerm = new UnreachableInst(*C, CrashBlock);
491 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
492 ReplaceInstWithInst(CheckTerm, NewTerm);
494 CrashTerm = splitBlockAndInsertIfThen(Cmp, true);
498 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
499 Crash->setDebugLoc(OrigIns->getDebugLoc());
502 void AddressSanitizer::createInitializerPoisonCalls(Module &M,
505 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
506 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
507 // If that function is not present, this TU contains no globals, or they have
508 // all been optimized away
512 // Set up the arguments to our poison/unpoison functions.
513 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
515 // Declare our poisoning and unpoisoning functions.
516 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
517 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
518 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
519 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
520 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
521 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
523 // Add a call to poison all external globals before the given function starts.
524 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
526 // Add calls to unpoison all globals before each return instruction.
527 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
529 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
530 CallInst::Create(AsanUnpoisonGlobals, "", RI);
535 bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
536 Type *Ty = cast<PointerType>(G->getType())->getElementType();
537 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
539 if (BL->isIn(*G)) return false;
540 if (!Ty->isSized()) return false;
541 if (!G->hasInitializer()) return false;
542 // Touch only those globals that will not be defined in other modules.
543 // Don't handle ODR type linkages since other modules may be built w/o asan.
544 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
545 G->getLinkage() != GlobalVariable::PrivateLinkage &&
546 G->getLinkage() != GlobalVariable::InternalLinkage)
548 // Two problems with thread-locals:
549 // - The address of the main thread's copy can't be computed at link-time.
550 // - Need to poison all copies, not just the main thread's one.
551 if (G->isThreadLocal())
553 // For now, just ignore this Alloca if the alignment is large.
554 if (G->getAlignment() > RedzoneSize) return false;
556 // Ignore all the globals with the names starting with "\01L_OBJC_".
557 // Many of those are put into the .cstring section. The linker compresses
558 // that section by removing the spare \0s after the string terminator, so
559 // our redzones get broken.
560 if ((G->getName().find("\01L_OBJC_") == 0) ||
561 (G->getName().find("\01l_OBJC_") == 0)) {
562 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
566 if (G->hasSection()) {
567 StringRef Section(G->getSection());
568 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
569 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
571 if ((Section.find("__OBJC,") == 0) ||
572 (Section.find("__DATA, __objc_") == 0)) {
573 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
576 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
577 // Constant CFString instances are compiled in the following way:
578 // -- the string buffer is emitted into
579 // __TEXT,__cstring,cstring_literals
580 // -- the constant NSConstantString structure referencing that buffer
581 // is placed into __DATA,__cfstring
582 // Therefore there's no point in placing redzones into __DATA,__cfstring.
583 // Moreover, it causes the linker to crash on OS X 10.7
584 if (Section.find("__DATA,__cfstring") == 0) {
585 DEBUG(dbgs() << "Ignoring CFString: " << *G);
593 // This function replaces all global variables with new variables that have
594 // trailing redzones. It also creates a function that poisons
595 // redzones and inserts this function into llvm.global_ctors.
596 bool AddressSanitizer::insertGlobalRedzones(Module &M) {
597 SmallVector<GlobalVariable *, 16> GlobalsToChange;
599 for (Module::GlobalListType::iterator G = M.global_begin(),
600 E = M.global_end(); G != E; ++G) {
601 if (ShouldInstrumentGlobal(G))
602 GlobalsToChange.push_back(G);
605 size_t n = GlobalsToChange.size();
606 if (n == 0) return false;
608 // A global is described by a structure
611 // size_t size_with_redzone;
613 // size_t has_dynamic_init;
614 // We initialize an array of such structures and pass it to a run-time call.
615 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
618 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
620 IRBuilder<> IRB(CtorInsertBefore);
623 FindDynamicInitializers(M);
625 // The addresses of the first and last dynamically initialized globals in
626 // this TU. Used in initialization order checking.
627 Value *FirstDynamic = 0, *LastDynamic = 0;
629 for (size_t i = 0; i < n; i++) {
630 GlobalVariable *G = GlobalsToChange[i];
631 PointerType *PtrTy = cast<PointerType>(G->getType());
632 Type *Ty = PtrTy->getElementType();
633 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
634 uint64_t RightRedzoneSize = RedzoneSize +
635 (RedzoneSize - (SizeInBytes % RedzoneSize));
636 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
637 // Determine whether this global should be poisoned in initialization.
638 bool GlobalHasDynamicInitializer = HasDynamicInitializer(G);
639 // Don't check initialization order if this global is blacklisted.
640 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
642 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
643 Constant *NewInitializer = ConstantStruct::get(
644 NewTy, G->getInitializer(),
645 Constant::getNullValue(RightRedZoneTy), NULL);
647 SmallString<2048> DescriptionOfGlobal = G->getName();
648 DescriptionOfGlobal += " (";
649 DescriptionOfGlobal += M.getModuleIdentifier();
650 DescriptionOfGlobal += ")";
651 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
653 // Create a new global variable with enough space for a redzone.
654 GlobalVariable *NewGlobal = new GlobalVariable(
655 M, NewTy, G->isConstant(), G->getLinkage(),
656 NewInitializer, "", G, G->getThreadLocalMode());
657 NewGlobal->copyAttributesFrom(G);
658 NewGlobal->setAlignment(RedzoneSize);
661 Indices2[0] = IRB.getInt32(0);
662 Indices2[1] = IRB.getInt32(0);
664 G->replaceAllUsesWith(
665 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
666 NewGlobal->takeName(G);
667 G->eraseFromParent();
669 Initializers[i] = ConstantStruct::get(
671 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
672 ConstantInt::get(IntptrTy, SizeInBytes),
673 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
674 ConstantExpr::getPointerCast(Name, IntptrTy),
675 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
678 // Populate the first and last globals declared in this TU.
679 if (ClInitializers && GlobalHasDynamicInitializer) {
680 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
681 if (FirstDynamic == 0)
682 FirstDynamic = LastDynamic;
685 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
688 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
689 GlobalVariable *AllGlobals = new GlobalVariable(
690 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
691 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
693 // Create calls for poisoning before initializers run and unpoisoning after.
694 if (ClInitializers && FirstDynamic && LastDynamic)
695 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
697 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
698 kAsanRegisterGlobalsName, IRB.getVoidTy(),
699 IntptrTy, IntptrTy, NULL));
700 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
702 IRB.CreateCall2(AsanRegisterGlobals,
703 IRB.CreatePointerCast(AllGlobals, IntptrTy),
704 ConstantInt::get(IntptrTy, n));
706 // We also need to unregister globals at the end, e.g. when a shared library
708 Function *AsanDtorFunction = Function::Create(
709 FunctionType::get(Type::getVoidTy(*C), false),
710 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
711 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
712 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
713 Function *AsanUnregisterGlobals =
714 checkInterfaceFunction(M.getOrInsertFunction(
715 kAsanUnregisterGlobalsName,
716 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
717 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
719 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
720 IRB.CreatePointerCast(AllGlobals, IntptrTy),
721 ConstantInt::get(IntptrTy, n));
722 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
729 bool AddressSanitizer::doInitialization(Module &M) {
730 // Initialize the private fields. No one has accessed them before.
731 TD = getAnalysisIfAvailable<DataLayout>();
735 BL.reset(new BlackList(ClBlackListFile));
737 C = &(M.getContext());
738 LongSize = TD->getPointerSizeInBits(0);
739 IntptrTy = Type::getIntNTy(*C, LongSize);
740 IntptrPtrTy = PointerType::get(IntptrTy, 0);
742 AsanCtorFunction = Function::Create(
743 FunctionType::get(Type::getVoidTy(*C), false),
744 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
745 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
746 CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
748 // call __asan_init in the module ctor.
749 IRBuilder<> IRB(CtorInsertBefore);
750 AsanInitFunction = checkInterfaceFunction(
751 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
752 AsanInitFunction->setLinkage(Function::ExternalLinkage);
753 IRB.CreateCall(AsanInitFunction);
755 // Create __asan_report* callbacks.
756 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
757 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
759 // IsWrite and TypeSize are encoded in the function name.
760 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
761 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
762 // If we are merging crash callbacks, they have two parameters.
763 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast<Function>(
764 M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
768 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
769 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
770 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
771 kAsanStackFreeName, IRB.getVoidTy(),
772 IntptrTy, IntptrTy, IntptrTy, NULL));
773 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
774 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
776 // We insert an empty inline asm after __asan_report* to avoid callback merge.
777 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
778 StringRef(""), StringRef(""),
779 /*hasSideEffects=*/true);
781 llvm::Triple targetTriple(M.getTargetTriple());
782 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
784 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
785 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
786 if (ClMappingOffsetLog >= 0) {
787 if (ClMappingOffsetLog == 0) {
791 MappingOffset = 1ULL << ClMappingOffsetLog;
794 MappingScale = kDefaultShadowScale;
795 if (ClMappingScale) {
796 MappingScale = ClMappingScale;
798 // Redzone used for stack and globals is at least 32 bytes.
799 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
800 RedzoneSize = std::max(32, (int)(1 << MappingScale));
803 if (ClMappingOffsetLog >= 0) {
804 // Tell the run-time the current values of mapping offset and scale.
805 GlobalValue *asan_mapping_offset =
806 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
807 ConstantInt::get(IntptrTy, MappingOffset),
808 kAsanMappingOffsetName);
809 // Read the global, otherwise it may be optimized away.
810 IRB.CreateLoad(asan_mapping_offset, true);
812 if (ClMappingScale) {
813 GlobalValue *asan_mapping_scale =
814 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
815 ConstantInt::get(IntptrTy, MappingScale),
816 kAsanMappingScaleName);
817 // Read the global, otherwise it may be optimized away.
818 IRB.CreateLoad(asan_mapping_scale, true);
821 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
826 bool AddressSanitizer::doFinalization(Module &M) {
827 // We transform the globals at the very end so that the optimization analysis
828 // works on the original globals.
830 return insertGlobalRedzones(M);
835 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
836 // For each NSObject descendant having a +load method, this method is invoked
837 // by the ObjC runtime before any of the static constructors is called.
838 // Therefore we need to instrument such methods with a call to __asan_init
839 // at the beginning in order to initialize our runtime before any access to
840 // the shadow memory.
841 // We cannot just ignore these methods, because they may call other
842 // instrumented functions.
843 if (F.getName().find(" load]") != std::string::npos) {
844 IRBuilder<> IRB(F.begin()->begin());
845 IRB.CreateCall(AsanInitFunction);
851 bool AddressSanitizer::runOnFunction(Function &F) {
852 if (BL->isIn(F)) return false;
853 if (&F == AsanCtorFunction) return false;
854 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
856 // If needed, insert __asan_init before checking for AddressSafety attr.
857 maybeInsertAsanInitAtFunctionEntry(F);
859 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
862 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
865 // We want to instrument every address only once per basic block (unless there
866 // are calls between uses).
867 SmallSet<Value*, 16> TempsToInstrument;
868 SmallVector<Instruction*, 16> ToInstrument;
869 SmallVector<Instruction*, 8> NoReturnCalls;
872 // Fill the set of memory operations to instrument.
873 for (Function::iterator FI = F.begin(), FE = F.end();
875 TempsToInstrument.clear();
876 int NumInsnsPerBB = 0;
877 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
879 if (LooksLikeCodeInBug11395(BI)) return false;
880 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
881 if (ClOpt && ClOptSameTemp) {
882 if (!TempsToInstrument.insert(Addr))
883 continue; // We've seen this temp in the current BB.
885 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
888 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
890 TempsToInstrument.clear();
891 if (CI->doesNotReturn()) {
892 NoReturnCalls.push_back(CI);
897 ToInstrument.push_back(BI);
899 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
905 int NumInstrumented = 0;
906 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
907 Instruction *Inst = ToInstrument[i];
908 if (ClDebugMin < 0 || ClDebugMax < 0 ||
909 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
910 if (isInterestingMemoryAccess(Inst, &IsWrite))
913 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
918 bool ChangedStack = poisonStackInFunction(F);
920 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
921 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
922 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
923 Instruction *CI = NoReturnCalls[i];
925 IRB.CreateCall(AsanHandleNoReturnFunc);
927 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
929 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
932 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
933 if (ShadowRedzoneSize == 1) return PoisonByte;
934 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
935 if (ShadowRedzoneSize == 4)
936 return (PoisonByte << 24) + (PoisonByte << 16) +
937 (PoisonByte << 8) + (PoisonByte);
938 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
941 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
944 size_t ShadowGranularity,
946 for (size_t i = 0; i < RedzoneSize;
947 i+= ShadowGranularity, Shadow++) {
948 if (i + ShadowGranularity <= Size) {
949 *Shadow = 0; // fully addressable
950 } else if (i >= Size) {
951 *Shadow = Magic; // unaddressable
953 *Shadow = Size - i; // first Size-i bytes are addressable
958 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
960 Value *ShadowBase, bool DoPoison) {
961 size_t ShadowRZSize = RedzoneSize >> MappingScale;
962 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
963 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
964 Type *RZPtrTy = PointerType::get(RZTy, 0);
966 Value *PoisonLeft = ConstantInt::get(RZTy,
967 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
968 Value *PoisonMid = ConstantInt::get(RZTy,
969 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
970 Value *PoisonRight = ConstantInt::get(RZTy,
971 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
973 // poison the first red zone.
974 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
976 // poison all other red zones.
977 uint64_t Pos = RedzoneSize;
978 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
979 AllocaInst *AI = AllocaVec[i];
980 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
981 uint64_t AlignedSize = getAlignedAllocaSize(AI);
982 assert(AlignedSize - SizeInBytes < RedzoneSize);
987 assert(ShadowBase->getType() == IntptrTy);
988 if (SizeInBytes < AlignedSize) {
989 // Poison the partial redzone at right
991 ShadowBase, ConstantInt::get(IntptrTy,
992 (Pos >> MappingScale) - ShadowRZSize));
993 size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
996 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
998 1ULL << MappingScale,
999 kAsanStackPartialRedzoneMagic);
1001 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
1002 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1005 // Poison the full redzone at right.
1006 Ptr = IRB.CreateAdd(ShadowBase,
1007 ConstantInt::get(IntptrTy, Pos >> MappingScale));
1008 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
1009 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1015 // Workaround for bug 11395: we don't want to instrument stack in functions
1016 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
1017 // FIXME: remove once the bug 11395 is fixed.
1018 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
1019 if (LongSize != 32) return false;
1020 CallInst *CI = dyn_cast<CallInst>(I);
1021 if (!CI || !CI->isInlineAsm()) return false;
1022 if (CI->getNumArgOperands() <= 5) return false;
1023 // We have inline assembly with quite a few arguments.
1027 // Find all static Alloca instructions and put
1028 // poisoned red zones around all of them.
1029 // Then unpoison everything back before the function returns.
1031 // Stack poisoning does not play well with exception handling.
1032 // When an exception is thrown, we essentially bypass the code
1033 // that unpoisones the stack. This is why the run-time library has
1034 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1035 // stack in the interceptor. This however does not work inside the
1036 // actual function which catches the exception. Most likely because the
1037 // compiler hoists the load of the shadow value somewhere too high.
1038 // This causes asan to report a non-existing bug on 453.povray.
1039 // It sounds like an LLVM bug.
1040 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1041 if (!ClStack) return false;
1042 SmallVector<AllocaInst*, 16> AllocaVec;
1043 SmallVector<Instruction*, 8> RetVec;
1044 uint64_t TotalSize = 0;
1046 // Filter out Alloca instructions we want (and can) handle.
1047 // Collect Ret instructions.
1048 for (Function::iterator FI = F.begin(), FE = F.end();
1050 BasicBlock &BB = *FI;
1051 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1053 if (isa<ReturnInst>(BI)) {
1054 RetVec.push_back(BI);
1058 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1060 if (AI->isArrayAllocation()) continue;
1061 if (!AI->isStaticAlloca()) continue;
1062 if (!AI->getAllocatedType()->isSized()) continue;
1063 if (AI->getAlignment() > RedzoneSize) continue;
1064 AllocaVec.push_back(AI);
1065 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1066 TotalSize += AlignedSize;
1070 if (AllocaVec.empty()) return false;
1072 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
1074 bool DoStackMalloc = ClUseAfterReturn
1075 && LocalStackSize <= kMaxStackMallocSize;
1077 Instruction *InsBefore = AllocaVec[0];
1078 IRBuilder<> IRB(InsBefore);
1081 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1082 AllocaInst *MyAlloca =
1083 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1084 MyAlloca->setAlignment(RedzoneSize);
1085 assert(MyAlloca->isStaticAlloca());
1086 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1087 Value *LocalStackBase = OrigStackBase;
1089 if (DoStackMalloc) {
1090 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1091 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1094 // This string will be parsed by the run-time (DescribeStackAddress).
1095 SmallString<2048> StackDescriptionStorage;
1096 raw_svector_ostream StackDescription(StackDescriptionStorage);
1097 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1099 uint64_t Pos = RedzoneSize;
1100 // Replace Alloca instructions with base+offset.
1101 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1102 AllocaInst *AI = AllocaVec[i];
1103 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1104 StringRef Name = AI->getName();
1105 StackDescription << Pos << " " << SizeInBytes << " "
1106 << Name.size() << " " << Name << " ";
1107 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1108 assert((AlignedSize % RedzoneSize) == 0);
1109 AI->replaceAllUsesWith(
1111 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1113 Pos += AlignedSize + RedzoneSize;
1115 assert(Pos == LocalStackSize);
1117 // Write the Magic value and the frame description constant to the redzone.
1118 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1119 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1121 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1122 ConstantInt::get(IntptrTy, LongSize/8));
1123 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1124 Value *Description = IRB.CreatePointerCast(
1125 createPrivateGlobalForString(*F.getParent(), StackDescription.str()),
1127 IRB.CreateStore(Description, BasePlus1);
1129 // Poison the stack redzones at the entry.
1130 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1131 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1133 // Unpoison the stack before all ret instructions.
1134 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1135 Instruction *Ret = RetVec[i];
1136 IRBuilder<> IRBRet(Ret);
1138 // Mark the current frame as retired.
1139 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1141 // Unpoison the stack.
1142 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1144 if (DoStackMalloc) {
1145 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1146 ConstantInt::get(IntptrTy, LocalStackSize),