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 /// A set of dynamically initialized globals extracted from metadata.
152 class SetOfDynamicallyInitializedGlobals {
154 void Init(Module& M) {
155 // Clang generates metadata identifying all dynamically initialized globals.
156 NamedMDNode *DynamicGlobals =
157 M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
160 for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
161 MDNode *MDN = DynamicGlobals->getOperand(i);
162 assert(MDN->getNumOperands() == 1);
163 Value *VG = MDN->getOperand(0);
164 // The optimizer may optimize away a global entirely, in which case we
165 // cannot instrument access to it.
168 DynInitGlobals.insert(cast<GlobalVariable>(VG));
171 bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
173 SmallSet<GlobalValue*, 32> DynInitGlobals;
177 /// AddressSanitizer: instrument the code in module to find memory bugs.
178 struct AddressSanitizer : public FunctionPass {
180 virtual const char *getPassName() const;
181 void instrumentMop(Instruction *I);
182 void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
183 Value *Addr, uint32_t TypeSize, bool IsWrite);
184 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
185 Value *ShadowValue, uint32_t TypeSize);
186 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
187 bool IsWrite, size_t AccessSizeIndex);
188 bool instrumentMemIntrinsic(MemIntrinsic *MI);
189 void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
191 Instruction *InsertBefore, bool IsWrite);
192 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
193 bool runOnFunction(Function &F);
194 void createInitializerPoisonCalls(Module &M,
195 Value *FirstAddr, Value *LastAddr);
196 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
197 bool poisonStackInFunction(Function &F);
198 virtual bool doInitialization(Module &M);
199 virtual bool doFinalization(Module &M);
200 bool insertGlobalRedzones(Module &M);
201 static char ID; // Pass identification, replacement for typeid
204 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
205 Type *Ty = AI->getAllocatedType();
206 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
209 uint64_t getAlignedSize(uint64_t SizeInBytes) {
210 return ((SizeInBytes + RedzoneSize - 1)
211 / RedzoneSize) * RedzoneSize;
213 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
214 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
215 return getAlignedSize(SizeInBytes);
218 Function *checkInterfaceFunction(Constant *FuncOrBitcast);
219 bool ShouldInstrumentGlobal(GlobalVariable *G);
220 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
221 Value *ShadowBase, bool DoPoison);
222 bool LooksLikeCodeInBug11395(Instruction *I);
223 void FindDynamicInitializers(Module &M);
227 uint64_t MappingOffset;
233 Function *AsanCtorFunction;
234 Function *AsanInitFunction;
235 Function *AsanStackMallocFunc, *AsanStackFreeFunc;
236 Function *AsanHandleNoReturnFunc;
237 Instruction *CtorInsertBefore;
238 OwningPtr<BlackList> BL;
239 // This array is indexed by AccessIsWrite and log2(AccessSize).
240 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
242 SmallSet<GlobalValue*, 32> GlobalsCreatedByAsan;
243 SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
248 char AddressSanitizer::ID = 0;
249 INITIALIZE_PASS(AddressSanitizer, "asan",
250 "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
252 AddressSanitizer::AddressSanitizer() : FunctionPass(ID) { }
253 FunctionPass *llvm::createAddressSanitizerPass() {
254 return new AddressSanitizer();
257 const char *AddressSanitizer::getPassName() const {
258 return "AddressSanitizer";
261 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
262 size_t Res = CountTrailingZeros_32(TypeSize / 8);
263 assert(Res < kNumberOfAccessSizes);
267 // Create a constant for Str so that we can pass it to the run-time lib.
268 static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
269 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
270 return new GlobalVariable(M, StrConst->getType(), true,
271 GlobalValue::PrivateLinkage, StrConst, "");
274 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
276 Shadow = IRB.CreateLShr(Shadow, MappingScale);
277 if (MappingOffset == 0)
279 // (Shadow >> scale) | offset
280 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
284 void AddressSanitizer::instrumentMemIntrinsicParam(
285 Instruction *OrigIns,
286 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
287 // Check the first byte.
289 IRBuilder<> IRB(InsertBefore);
290 instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
292 // Check the last byte.
294 IRBuilder<> IRB(InsertBefore);
295 Value *SizeMinusOne = IRB.CreateSub(
296 Size, ConstantInt::get(Size->getType(), 1));
297 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
298 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
299 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
300 instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
304 // Instrument memset/memmove/memcpy
305 bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
306 Value *Dst = MI->getDest();
307 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
308 Value *Src = MemTran ? MemTran->getSource() : 0;
309 Value *Length = MI->getLength();
311 Constant *ConstLength = dyn_cast<Constant>(Length);
312 Instruction *InsertBefore = MI;
314 if (ConstLength->isNullValue()) return false;
316 // The size is not a constant so it could be zero -- check at run-time.
317 IRBuilder<> IRB(InsertBefore);
319 Value *Cmp = IRB.CreateICmpNE(Length,
320 Constant::getNullValue(Length->getType()));
321 InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
324 instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
326 instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
330 // If I is an interesting memory access, return the PointerOperand
331 // and set IsWrite. Otherwise return NULL.
332 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
333 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
334 if (!ClInstrumentReads) return NULL;
336 return LI->getPointerOperand();
338 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
339 if (!ClInstrumentWrites) return NULL;
341 return SI->getPointerOperand();
343 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
344 if (!ClInstrumentAtomics) return NULL;
346 return RMW->getPointerOperand();
348 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
349 if (!ClInstrumentAtomics) return NULL;
351 return XCHG->getPointerOperand();
356 void AddressSanitizer::instrumentMop(Instruction *I) {
357 bool IsWrite = false;
358 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
360 if (ClOpt && ClOptGlobals) {
361 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
362 // If initialization order checking is disabled, a simple access to a
363 // dynamically initialized global is always valid.
366 // If a global variable does not have dynamic initialization we don't
367 // have to instrument it. However, if a global does not have initailizer
368 // at all, we assume it has dynamic initializer (in other TU).
369 if (G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G))
374 Type *OrigPtrTy = Addr->getType();
375 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
377 assert(OrigTy->isSized());
378 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
380 if (TypeSize != 8 && TypeSize != 16 &&
381 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
382 // Ignore all unusual sizes.
387 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
390 // Validate the result of Module::getOrInsertFunction called for an interface
391 // function of AddressSanitizer. If the instrumented module defines a function
392 // with the same name, their prototypes must match, otherwise
393 // getOrInsertFunction returns a bitcast.
394 Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
395 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
396 FuncOrBitcast->dump();
397 report_fatal_error("trying to redefine an AddressSanitizer "
398 "interface function");
401 Instruction *AddressSanitizer::generateCrashCode(
402 Instruction *InsertBefore, Value *Addr,
403 bool IsWrite, size_t AccessSizeIndex) {
404 IRBuilder<> IRB(InsertBefore);
405 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
407 // We don't do Call->setDoesNotReturn() because the BB already has
408 // UnreachableInst at the end.
409 // This EmptyAsm is required to avoid callback merge.
410 IRB.CreateCall(EmptyAsm);
414 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
417 size_t Granularity = 1 << MappingScale;
418 // Addr & (Granularity - 1)
419 Value *LastAccessedByte = IRB.CreateAnd(
420 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
421 // (Addr & (Granularity - 1)) + size - 1
422 if (TypeSize / 8 > 1)
423 LastAccessedByte = IRB.CreateAdd(
424 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
425 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
426 LastAccessedByte = IRB.CreateIntCast(
427 LastAccessedByte, ShadowValue->getType(), false);
428 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
429 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
432 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
433 IRBuilder<> &IRB, Value *Addr,
434 uint32_t TypeSize, bool IsWrite) {
435 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
437 Type *ShadowTy = IntegerType::get(
438 *C, std::max(8U, TypeSize >> MappingScale));
439 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
440 Value *ShadowPtr = memToShadow(AddrLong, IRB);
441 Value *CmpVal = Constant::getNullValue(ShadowTy);
442 Value *ShadowValue = IRB.CreateLoad(
443 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
445 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
446 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
447 size_t Granularity = 1 << MappingScale;
448 TerminatorInst *CrashTerm = 0;
450 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
451 TerminatorInst *CheckTerm =
452 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
453 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
454 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
455 IRB.SetInsertPoint(CheckTerm);
456 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
457 BasicBlock *CrashBlock =
458 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
459 CrashTerm = new UnreachableInst(*C, CrashBlock);
460 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
461 ReplaceInstWithInst(CheckTerm, NewTerm);
463 CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
467 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
468 Crash->setDebugLoc(OrigIns->getDebugLoc());
471 void AddressSanitizer::createInitializerPoisonCalls(Module &M,
474 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
475 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
476 // If that function is not present, this TU contains no globals, or they have
477 // all been optimized away
481 // Set up the arguments to our poison/unpoison functions.
482 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
484 // Declare our poisoning and unpoisoning functions.
485 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
486 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
487 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
488 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
489 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
490 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
492 // Add a call to poison all external globals before the given function starts.
493 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
495 // Add calls to unpoison all globals before each return instruction.
496 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
498 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
499 CallInst::Create(AsanUnpoisonGlobals, "", RI);
504 bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
505 Type *Ty = cast<PointerType>(G->getType())->getElementType();
506 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
508 if (BL->isIn(*G)) return false;
509 if (!Ty->isSized()) return false;
510 if (!G->hasInitializer()) return false;
511 if (GlobalsCreatedByAsan.count(G)) return false; // Our own global.
512 // Touch only those globals that will not be defined in other modules.
513 // Don't handle ODR type linkages since other modules may be built w/o asan.
514 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
515 G->getLinkage() != GlobalVariable::PrivateLinkage &&
516 G->getLinkage() != GlobalVariable::InternalLinkage)
518 // Two problems with thread-locals:
519 // - The address of the main thread's copy can't be computed at link-time.
520 // - Need to poison all copies, not just the main thread's one.
521 if (G->isThreadLocal())
523 // For now, just ignore this Alloca if the alignment is large.
524 if (G->getAlignment() > RedzoneSize) return false;
526 // Ignore all the globals with the names starting with "\01L_OBJC_".
527 // Many of those are put into the .cstring section. The linker compresses
528 // that section by removing the spare \0s after the string terminator, so
529 // our redzones get broken.
530 if ((G->getName().find("\01L_OBJC_") == 0) ||
531 (G->getName().find("\01l_OBJC_") == 0)) {
532 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
536 if (G->hasSection()) {
537 StringRef Section(G->getSection());
538 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
539 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
541 if ((Section.find("__OBJC,") == 0) ||
542 (Section.find("__DATA, __objc_") == 0)) {
543 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
546 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
547 // Constant CFString instances are compiled in the following way:
548 // -- the string buffer is emitted into
549 // __TEXT,__cstring,cstring_literals
550 // -- the constant NSConstantString structure referencing that buffer
551 // is placed into __DATA,__cfstring
552 // Therefore there's no point in placing redzones into __DATA,__cfstring.
553 // Moreover, it causes the linker to crash on OS X 10.7
554 if (Section.find("__DATA,__cfstring") == 0) {
555 DEBUG(dbgs() << "Ignoring CFString: " << *G);
563 // This function replaces all global variables with new variables that have
564 // trailing redzones. It also creates a function that poisons
565 // redzones and inserts this function into llvm.global_ctors.
566 bool AddressSanitizer::insertGlobalRedzones(Module &M) {
567 SmallVector<GlobalVariable *, 16> GlobalsToChange;
569 for (Module::GlobalListType::iterator G = M.global_begin(),
570 E = M.global_end(); G != E; ++G) {
571 if (ShouldInstrumentGlobal(G))
572 GlobalsToChange.push_back(G);
575 size_t n = GlobalsToChange.size();
576 if (n == 0) return false;
578 // A global is described by a structure
581 // size_t size_with_redzone;
583 // size_t has_dynamic_init;
584 // We initialize an array of such structures and pass it to a run-time call.
585 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
588 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
590 IRBuilder<> IRB(CtorInsertBefore);
592 // The addresses of the first and last dynamically initialized globals in
593 // this TU. Used in initialization order checking.
594 Value *FirstDynamic = 0, *LastDynamic = 0;
596 for (size_t i = 0; i < n; i++) {
597 GlobalVariable *G = GlobalsToChange[i];
598 PointerType *PtrTy = cast<PointerType>(G->getType());
599 Type *Ty = PtrTy->getElementType();
600 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
601 uint64_t RightRedzoneSize = RedzoneSize +
602 (RedzoneSize - (SizeInBytes % RedzoneSize));
603 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
604 // Determine whether this global should be poisoned in initialization.
605 bool GlobalHasDynamicInitializer =
606 DynamicallyInitializedGlobals.Contains(G);
607 // Don't check initialization order if this global is blacklisted.
608 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
610 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
611 Constant *NewInitializer = ConstantStruct::get(
612 NewTy, G->getInitializer(),
613 Constant::getNullValue(RightRedZoneTy), NULL);
615 SmallString<2048> DescriptionOfGlobal = G->getName();
616 DescriptionOfGlobal += " (";
617 DescriptionOfGlobal += M.getModuleIdentifier();
618 DescriptionOfGlobal += ")";
619 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
621 // Create a new global variable with enough space for a redzone.
622 GlobalVariable *NewGlobal = new GlobalVariable(
623 M, NewTy, G->isConstant(), G->getLinkage(),
624 NewInitializer, "", G, G->getThreadLocalMode());
625 NewGlobal->copyAttributesFrom(G);
626 NewGlobal->setAlignment(RedzoneSize);
629 Indices2[0] = IRB.getInt32(0);
630 Indices2[1] = IRB.getInt32(0);
632 G->replaceAllUsesWith(
633 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
634 NewGlobal->takeName(G);
635 G->eraseFromParent();
637 Initializers[i] = ConstantStruct::get(
639 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
640 ConstantInt::get(IntptrTy, SizeInBytes),
641 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
642 ConstantExpr::getPointerCast(Name, IntptrTy),
643 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
646 // Populate the first and last globals declared in this TU.
647 if (ClInitializers && GlobalHasDynamicInitializer) {
648 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
649 if (FirstDynamic == 0)
650 FirstDynamic = LastDynamic;
653 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
656 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
657 GlobalVariable *AllGlobals = new GlobalVariable(
658 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
659 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
661 // Create calls for poisoning before initializers run and unpoisoning after.
662 if (ClInitializers && FirstDynamic && LastDynamic)
663 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
665 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
666 kAsanRegisterGlobalsName, IRB.getVoidTy(),
667 IntptrTy, IntptrTy, NULL));
668 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
670 IRB.CreateCall2(AsanRegisterGlobals,
671 IRB.CreatePointerCast(AllGlobals, IntptrTy),
672 ConstantInt::get(IntptrTy, n));
674 // We also need to unregister globals at the end, e.g. when a shared library
676 Function *AsanDtorFunction = Function::Create(
677 FunctionType::get(Type::getVoidTy(*C), false),
678 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
679 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
680 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
681 Function *AsanUnregisterGlobals =
682 checkInterfaceFunction(M.getOrInsertFunction(
683 kAsanUnregisterGlobalsName,
684 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
685 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
687 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
688 IRB.CreatePointerCast(AllGlobals, IntptrTy),
689 ConstantInt::get(IntptrTy, n));
690 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
697 bool AddressSanitizer::doInitialization(Module &M) {
698 // Initialize the private fields. No one has accessed them before.
699 TD = getAnalysisIfAvailable<DataLayout>();
703 BL.reset(new BlackList(ClBlackListFile));
704 DynamicallyInitializedGlobals.Init(M);
706 C = &(M.getContext());
707 LongSize = TD->getPointerSizeInBits();
708 IntptrTy = Type::getIntNTy(*C, LongSize);
709 IntptrPtrTy = PointerType::get(IntptrTy, 0);
711 AsanCtorFunction = Function::Create(
712 FunctionType::get(Type::getVoidTy(*C), false),
713 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
714 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
715 CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
717 // call __asan_init in the module ctor.
718 IRBuilder<> IRB(CtorInsertBefore);
719 AsanInitFunction = checkInterfaceFunction(
720 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
721 AsanInitFunction->setLinkage(Function::ExternalLinkage);
722 IRB.CreateCall(AsanInitFunction);
724 // Create __asan_report* callbacks.
725 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
726 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
728 // IsWrite and TypeSize are encoded in the function name.
729 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
730 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
731 // If we are merging crash callbacks, they have two parameters.
732 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
733 checkInterfaceFunction(M.getOrInsertFunction(
734 FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
738 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
739 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
740 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
741 kAsanStackFreeName, IRB.getVoidTy(),
742 IntptrTy, IntptrTy, IntptrTy, NULL));
743 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
744 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
746 // We insert an empty inline asm after __asan_report* to avoid callback merge.
747 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
748 StringRef(""), StringRef(""),
749 /*hasSideEffects=*/true);
751 llvm::Triple targetTriple(M.getTargetTriple());
752 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
754 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
755 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
756 if (ClMappingOffsetLog >= 0) {
757 if (ClMappingOffsetLog == 0) {
761 MappingOffset = 1ULL << ClMappingOffsetLog;
764 MappingScale = kDefaultShadowScale;
765 if (ClMappingScale) {
766 MappingScale = ClMappingScale;
768 // Redzone used for stack and globals is at least 32 bytes.
769 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
770 RedzoneSize = std::max(32, (int)(1 << MappingScale));
773 if (ClMappingOffsetLog >= 0) {
774 // Tell the run-time the current values of mapping offset and scale.
775 GlobalValue *asan_mapping_offset =
776 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
777 ConstantInt::get(IntptrTy, MappingOffset),
778 kAsanMappingOffsetName);
779 // Read the global, otherwise it may be optimized away.
780 IRB.CreateLoad(asan_mapping_offset, true);
782 if (ClMappingScale) {
783 GlobalValue *asan_mapping_scale =
784 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
785 ConstantInt::get(IntptrTy, MappingScale),
786 kAsanMappingScaleName);
787 // Read the global, otherwise it may be optimized away.
788 IRB.CreateLoad(asan_mapping_scale, true);
791 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
796 bool AddressSanitizer::doFinalization(Module &M) {
797 // We transform the globals at the very end so that the optimization analysis
798 // works on the original globals.
800 return insertGlobalRedzones(M);
805 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
806 // For each NSObject descendant having a +load method, this method is invoked
807 // by the ObjC runtime before any of the static constructors is called.
808 // Therefore we need to instrument such methods with a call to __asan_init
809 // at the beginning in order to initialize our runtime before any access to
810 // the shadow memory.
811 // We cannot just ignore these methods, because they may call other
812 // instrumented functions.
813 if (F.getName().find(" load]") != std::string::npos) {
814 IRBuilder<> IRB(F.begin()->begin());
815 IRB.CreateCall(AsanInitFunction);
821 bool AddressSanitizer::runOnFunction(Function &F) {
822 if (BL->isIn(F)) return false;
823 if (&F == AsanCtorFunction) return false;
824 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
826 // If needed, insert __asan_init before checking for AddressSafety attr.
827 maybeInsertAsanInitAtFunctionEntry(F);
829 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
832 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
835 // We want to instrument every address only once per basic block (unless there
836 // are calls between uses).
837 SmallSet<Value*, 16> TempsToInstrument;
838 SmallVector<Instruction*, 16> ToInstrument;
839 SmallVector<Instruction*, 8> NoReturnCalls;
842 // Fill the set of memory operations to instrument.
843 for (Function::iterator FI = F.begin(), FE = F.end();
845 TempsToInstrument.clear();
846 int NumInsnsPerBB = 0;
847 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
849 if (LooksLikeCodeInBug11395(BI)) return false;
850 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
851 if (ClOpt && ClOptSameTemp) {
852 if (!TempsToInstrument.insert(Addr))
853 continue; // We've seen this temp in the current BB.
855 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
858 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
860 TempsToInstrument.clear();
861 if (CI->doesNotReturn()) {
862 NoReturnCalls.push_back(CI);
867 ToInstrument.push_back(BI);
869 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
875 int NumInstrumented = 0;
876 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
877 Instruction *Inst = ToInstrument[i];
878 if (ClDebugMin < 0 || ClDebugMax < 0 ||
879 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
880 if (isInterestingMemoryAccess(Inst, &IsWrite))
883 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
888 bool ChangedStack = poisonStackInFunction(F);
890 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
891 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
892 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
893 Instruction *CI = NoReturnCalls[i];
895 IRB.CreateCall(AsanHandleNoReturnFunc);
897 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
899 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
902 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
903 if (ShadowRedzoneSize == 1) return PoisonByte;
904 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
905 if (ShadowRedzoneSize == 4)
906 return (PoisonByte << 24) + (PoisonByte << 16) +
907 (PoisonByte << 8) + (PoisonByte);
908 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
911 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
914 size_t ShadowGranularity,
916 for (size_t i = 0; i < RedzoneSize;
917 i+= ShadowGranularity, Shadow++) {
918 if (i + ShadowGranularity <= Size) {
919 *Shadow = 0; // fully addressable
920 } else if (i >= Size) {
921 *Shadow = Magic; // unaddressable
923 *Shadow = Size - i; // first Size-i bytes are addressable
928 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
930 Value *ShadowBase, bool DoPoison) {
931 size_t ShadowRZSize = RedzoneSize >> MappingScale;
932 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
933 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
934 Type *RZPtrTy = PointerType::get(RZTy, 0);
936 Value *PoisonLeft = ConstantInt::get(RZTy,
937 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
938 Value *PoisonMid = ConstantInt::get(RZTy,
939 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
940 Value *PoisonRight = ConstantInt::get(RZTy,
941 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
943 // poison the first red zone.
944 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
946 // poison all other red zones.
947 uint64_t Pos = RedzoneSize;
948 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
949 AllocaInst *AI = AllocaVec[i];
950 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
951 uint64_t AlignedSize = getAlignedAllocaSize(AI);
952 assert(AlignedSize - SizeInBytes < RedzoneSize);
957 assert(ShadowBase->getType() == IntptrTy);
958 if (SizeInBytes < AlignedSize) {
959 // Poison the partial redzone at right
961 ShadowBase, ConstantInt::get(IntptrTy,
962 (Pos >> MappingScale) - ShadowRZSize));
963 size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
966 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
968 1ULL << MappingScale,
969 kAsanStackPartialRedzoneMagic);
971 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
972 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
975 // Poison the full redzone at right.
976 Ptr = IRB.CreateAdd(ShadowBase,
977 ConstantInt::get(IntptrTy, Pos >> MappingScale));
978 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
979 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
985 // Workaround for bug 11395: we don't want to instrument stack in functions
986 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
987 // FIXME: remove once the bug 11395 is fixed.
988 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
989 if (LongSize != 32) return false;
990 CallInst *CI = dyn_cast<CallInst>(I);
991 if (!CI || !CI->isInlineAsm()) return false;
992 if (CI->getNumArgOperands() <= 5) return false;
993 // We have inline assembly with quite a few arguments.
997 // Find all static Alloca instructions and put
998 // poisoned red zones around all of them.
999 // Then unpoison everything back before the function returns.
1001 // Stack poisoning does not play well with exception handling.
1002 // When an exception is thrown, we essentially bypass the code
1003 // that unpoisones the stack. This is why the run-time library has
1004 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1005 // stack in the interceptor. This however does not work inside the
1006 // actual function which catches the exception. Most likely because the
1007 // compiler hoists the load of the shadow value somewhere too high.
1008 // This causes asan to report a non-existing bug on 453.povray.
1009 // It sounds like an LLVM bug.
1010 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1011 if (!ClStack) return false;
1012 SmallVector<AllocaInst*, 16> AllocaVec;
1013 SmallVector<Instruction*, 8> RetVec;
1014 uint64_t TotalSize = 0;
1016 // Filter out Alloca instructions we want (and can) handle.
1017 // Collect Ret instructions.
1018 for (Function::iterator FI = F.begin(), FE = F.end();
1020 BasicBlock &BB = *FI;
1021 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1023 if (isa<ReturnInst>(BI)) {
1024 RetVec.push_back(BI);
1028 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1030 if (AI->isArrayAllocation()) continue;
1031 if (!AI->isStaticAlloca()) continue;
1032 if (!AI->getAllocatedType()->isSized()) continue;
1033 if (AI->getAlignment() > RedzoneSize) continue;
1034 AllocaVec.push_back(AI);
1035 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1036 TotalSize += AlignedSize;
1040 if (AllocaVec.empty()) return false;
1042 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
1044 bool DoStackMalloc = ClUseAfterReturn
1045 && LocalStackSize <= kMaxStackMallocSize;
1047 Instruction *InsBefore = AllocaVec[0];
1048 IRBuilder<> IRB(InsBefore);
1051 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1052 AllocaInst *MyAlloca =
1053 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1054 MyAlloca->setAlignment(RedzoneSize);
1055 assert(MyAlloca->isStaticAlloca());
1056 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1057 Value *LocalStackBase = OrigStackBase;
1059 if (DoStackMalloc) {
1060 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1061 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1064 // This string will be parsed by the run-time (DescribeStackAddress).
1065 SmallString<2048> StackDescriptionStorage;
1066 raw_svector_ostream StackDescription(StackDescriptionStorage);
1067 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1069 uint64_t Pos = RedzoneSize;
1070 // Replace Alloca instructions with base+offset.
1071 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1072 AllocaInst *AI = AllocaVec[i];
1073 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1074 StringRef Name = AI->getName();
1075 StackDescription << Pos << " " << SizeInBytes << " "
1076 << Name.size() << " " << Name << " ";
1077 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1078 assert((AlignedSize % RedzoneSize) == 0);
1079 AI->replaceAllUsesWith(
1081 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1083 Pos += AlignedSize + RedzoneSize;
1085 assert(Pos == LocalStackSize);
1087 // Write the Magic value and the frame description constant to the redzone.
1088 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1089 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1091 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1092 ConstantInt::get(IntptrTy, LongSize/8));
1093 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1094 GlobalVariable *StackDescriptionGlobal =
1095 createPrivateGlobalForString(*F.getParent(), StackDescription.str());
1096 GlobalsCreatedByAsan.insert(StackDescriptionGlobal);
1097 Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
1098 IRB.CreateStore(Description, BasePlus1);
1100 // Poison the stack redzones at the entry.
1101 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1102 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1104 // Unpoison the stack before all ret instructions.
1105 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1106 Instruction *Ret = RetVec[i];
1107 IRBuilder<> IRBRet(Ret);
1109 // Mark the current frame as retired.
1110 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1112 // Unpoison the stack.
1113 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1115 if (DoStackMalloc) {
1116 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1117 ConstantInt::get(IntptrTy, LocalStackSize),
1122 // We are done. Remove the old unused alloca instructions.
1123 for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
1124 AllocaVec[i]->eraseFromParent();