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 has external linkage, we
368 // assume it has dynamic initialization, as it may have an initializer
369 // in a different TU.
370 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
371 !DynamicallyInitializedGlobals.Contains(G))
376 Type *OrigPtrTy = Addr->getType();
377 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
379 assert(OrigTy->isSized());
380 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
382 if (TypeSize != 8 && TypeSize != 16 &&
383 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
384 // Ignore all unusual sizes.
389 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
392 // Validate the result of Module::getOrInsertFunction called for an interface
393 // function of AddressSanitizer. If the instrumented module defines a function
394 // with the same name, their prototypes must match, otherwise
395 // getOrInsertFunction returns a bitcast.
396 Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
397 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
398 FuncOrBitcast->dump();
399 report_fatal_error("trying to redefine an AddressSanitizer "
400 "interface function");
403 Instruction *AddressSanitizer::generateCrashCode(
404 Instruction *InsertBefore, Value *Addr,
405 bool IsWrite, size_t AccessSizeIndex) {
406 IRBuilder<> IRB(InsertBefore);
407 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
409 // We don't do Call->setDoesNotReturn() because the BB already has
410 // UnreachableInst at the end.
411 // This EmptyAsm is required to avoid callback merge.
412 IRB.CreateCall(EmptyAsm);
416 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
419 size_t Granularity = 1 << MappingScale;
420 // Addr & (Granularity - 1)
421 Value *LastAccessedByte = IRB.CreateAnd(
422 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
423 // (Addr & (Granularity - 1)) + size - 1
424 if (TypeSize / 8 > 1)
425 LastAccessedByte = IRB.CreateAdd(
426 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
427 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
428 LastAccessedByte = IRB.CreateIntCast(
429 LastAccessedByte, ShadowValue->getType(), false);
430 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
431 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
434 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
435 IRBuilder<> &IRB, Value *Addr,
436 uint32_t TypeSize, bool IsWrite) {
437 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
439 Type *ShadowTy = IntegerType::get(
440 *C, std::max(8U, TypeSize >> MappingScale));
441 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
442 Value *ShadowPtr = memToShadow(AddrLong, IRB);
443 Value *CmpVal = Constant::getNullValue(ShadowTy);
444 Value *ShadowValue = IRB.CreateLoad(
445 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
447 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
448 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
449 size_t Granularity = 1 << MappingScale;
450 TerminatorInst *CrashTerm = 0;
452 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
453 TerminatorInst *CheckTerm =
454 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
455 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
456 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
457 IRB.SetInsertPoint(CheckTerm);
458 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
459 BasicBlock *CrashBlock =
460 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
461 CrashTerm = new UnreachableInst(*C, CrashBlock);
462 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
463 ReplaceInstWithInst(CheckTerm, NewTerm);
465 CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
469 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
470 Crash->setDebugLoc(OrigIns->getDebugLoc());
473 void AddressSanitizer::createInitializerPoisonCalls(Module &M,
476 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
477 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
478 // If that function is not present, this TU contains no globals, or they have
479 // all been optimized away
483 // Set up the arguments to our poison/unpoison functions.
484 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
486 // Declare our poisoning and unpoisoning functions.
487 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
488 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
489 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
490 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
491 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
492 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
494 // Add a call to poison all external globals before the given function starts.
495 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
497 // Add calls to unpoison all globals before each return instruction.
498 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
500 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
501 CallInst::Create(AsanUnpoisonGlobals, "", RI);
506 bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
507 Type *Ty = cast<PointerType>(G->getType())->getElementType();
508 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
510 if (BL->isIn(*G)) return false;
511 if (!Ty->isSized()) return false;
512 if (!G->hasInitializer()) return false;
513 if (GlobalsCreatedByAsan.count(G)) return false; // Our own global.
514 // Touch only those globals that will not be defined in other modules.
515 // Don't handle ODR type linkages since other modules may be built w/o asan.
516 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
517 G->getLinkage() != GlobalVariable::PrivateLinkage &&
518 G->getLinkage() != GlobalVariable::InternalLinkage)
520 // Two problems with thread-locals:
521 // - The address of the main thread's copy can't be computed at link-time.
522 // - Need to poison all copies, not just the main thread's one.
523 if (G->isThreadLocal())
525 // For now, just ignore this Alloca if the alignment is large.
526 if (G->getAlignment() > RedzoneSize) return false;
528 // Ignore all the globals with the names starting with "\01L_OBJC_".
529 // Many of those are put into the .cstring section. The linker compresses
530 // that section by removing the spare \0s after the string terminator, so
531 // our redzones get broken.
532 if ((G->getName().find("\01L_OBJC_") == 0) ||
533 (G->getName().find("\01l_OBJC_") == 0)) {
534 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
538 if (G->hasSection()) {
539 StringRef Section(G->getSection());
540 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
541 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
543 if ((Section.find("__OBJC,") == 0) ||
544 (Section.find("__DATA, __objc_") == 0)) {
545 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
548 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
549 // Constant CFString instances are compiled in the following way:
550 // -- the string buffer is emitted into
551 // __TEXT,__cstring,cstring_literals
552 // -- the constant NSConstantString structure referencing that buffer
553 // is placed into __DATA,__cfstring
554 // Therefore there's no point in placing redzones into __DATA,__cfstring.
555 // Moreover, it causes the linker to crash on OS X 10.7
556 if (Section.find("__DATA,__cfstring") == 0) {
557 DEBUG(dbgs() << "Ignoring CFString: " << *G);
565 // This function replaces all global variables with new variables that have
566 // trailing redzones. It also creates a function that poisons
567 // redzones and inserts this function into llvm.global_ctors.
568 bool AddressSanitizer::insertGlobalRedzones(Module &M) {
569 SmallVector<GlobalVariable *, 16> GlobalsToChange;
571 for (Module::GlobalListType::iterator G = M.global_begin(),
572 E = M.global_end(); G != E; ++G) {
573 if (ShouldInstrumentGlobal(G))
574 GlobalsToChange.push_back(G);
577 size_t n = GlobalsToChange.size();
578 if (n == 0) return false;
580 // A global is described by a structure
583 // size_t size_with_redzone;
585 // size_t has_dynamic_init;
586 // We initialize an array of such structures and pass it to a run-time call.
587 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
590 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
592 IRBuilder<> IRB(CtorInsertBefore);
594 // The addresses of the first and last dynamically initialized globals in
595 // this TU. Used in initialization order checking.
596 Value *FirstDynamic = 0, *LastDynamic = 0;
598 for (size_t i = 0; i < n; i++) {
599 GlobalVariable *G = GlobalsToChange[i];
600 PointerType *PtrTy = cast<PointerType>(G->getType());
601 Type *Ty = PtrTy->getElementType();
602 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
603 uint64_t RightRedzoneSize = RedzoneSize +
604 (RedzoneSize - (SizeInBytes % RedzoneSize));
605 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
606 // Determine whether this global should be poisoned in initialization.
607 bool GlobalHasDynamicInitializer =
608 DynamicallyInitializedGlobals.Contains(G);
609 // Don't check initialization order if this global is blacklisted.
610 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
612 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
613 Constant *NewInitializer = ConstantStruct::get(
614 NewTy, G->getInitializer(),
615 Constant::getNullValue(RightRedZoneTy), NULL);
617 SmallString<2048> DescriptionOfGlobal = G->getName();
618 DescriptionOfGlobal += " (";
619 DescriptionOfGlobal += M.getModuleIdentifier();
620 DescriptionOfGlobal += ")";
621 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
623 // Create a new global variable with enough space for a redzone.
624 GlobalVariable *NewGlobal = new GlobalVariable(
625 M, NewTy, G->isConstant(), G->getLinkage(),
626 NewInitializer, "", G, G->getThreadLocalMode());
627 NewGlobal->copyAttributesFrom(G);
628 NewGlobal->setAlignment(RedzoneSize);
631 Indices2[0] = IRB.getInt32(0);
632 Indices2[1] = IRB.getInt32(0);
634 G->replaceAllUsesWith(
635 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
636 NewGlobal->takeName(G);
637 G->eraseFromParent();
639 Initializers[i] = ConstantStruct::get(
641 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
642 ConstantInt::get(IntptrTy, SizeInBytes),
643 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
644 ConstantExpr::getPointerCast(Name, IntptrTy),
645 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
648 // Populate the first and last globals declared in this TU.
649 if (ClInitializers && GlobalHasDynamicInitializer) {
650 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
651 if (FirstDynamic == 0)
652 FirstDynamic = LastDynamic;
655 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
658 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
659 GlobalVariable *AllGlobals = new GlobalVariable(
660 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
661 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
663 // Create calls for poisoning before initializers run and unpoisoning after.
664 if (ClInitializers && FirstDynamic && LastDynamic)
665 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
667 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
668 kAsanRegisterGlobalsName, IRB.getVoidTy(),
669 IntptrTy, IntptrTy, NULL));
670 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
672 IRB.CreateCall2(AsanRegisterGlobals,
673 IRB.CreatePointerCast(AllGlobals, IntptrTy),
674 ConstantInt::get(IntptrTy, n));
676 // We also need to unregister globals at the end, e.g. when a shared library
678 Function *AsanDtorFunction = Function::Create(
679 FunctionType::get(Type::getVoidTy(*C), false),
680 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
681 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
682 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
683 Function *AsanUnregisterGlobals =
684 checkInterfaceFunction(M.getOrInsertFunction(
685 kAsanUnregisterGlobalsName,
686 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
687 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
689 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
690 IRB.CreatePointerCast(AllGlobals, IntptrTy),
691 ConstantInt::get(IntptrTy, n));
692 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
699 bool AddressSanitizer::doInitialization(Module &M) {
700 // Initialize the private fields. No one has accessed them before.
701 TD = getAnalysisIfAvailable<DataLayout>();
705 BL.reset(new BlackList(ClBlackListFile));
706 DynamicallyInitializedGlobals.Init(M);
708 C = &(M.getContext());
709 LongSize = TD->getPointerSizeInBits();
710 IntptrTy = Type::getIntNTy(*C, LongSize);
711 IntptrPtrTy = PointerType::get(IntptrTy, 0);
713 AsanCtorFunction = Function::Create(
714 FunctionType::get(Type::getVoidTy(*C), false),
715 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
716 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
717 CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
719 // call __asan_init in the module ctor.
720 IRBuilder<> IRB(CtorInsertBefore);
721 AsanInitFunction = checkInterfaceFunction(
722 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
723 AsanInitFunction->setLinkage(Function::ExternalLinkage);
724 IRB.CreateCall(AsanInitFunction);
726 // Create __asan_report* callbacks.
727 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
728 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
730 // IsWrite and TypeSize are encoded in the function name.
731 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
732 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
733 // If we are merging crash callbacks, they have two parameters.
734 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
735 checkInterfaceFunction(M.getOrInsertFunction(
736 FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
740 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
741 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
742 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
743 kAsanStackFreeName, IRB.getVoidTy(),
744 IntptrTy, IntptrTy, IntptrTy, NULL));
745 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
746 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
748 // We insert an empty inline asm after __asan_report* to avoid callback merge.
749 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
750 StringRef(""), StringRef(""),
751 /*hasSideEffects=*/true);
753 llvm::Triple targetTriple(M.getTargetTriple());
754 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
756 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
757 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
758 if (ClMappingOffsetLog >= 0) {
759 if (ClMappingOffsetLog == 0) {
763 MappingOffset = 1ULL << ClMappingOffsetLog;
766 MappingScale = kDefaultShadowScale;
767 if (ClMappingScale) {
768 MappingScale = ClMappingScale;
770 // Redzone used for stack and globals is at least 32 bytes.
771 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
772 RedzoneSize = std::max(32, (int)(1 << MappingScale));
775 if (ClMappingOffsetLog >= 0) {
776 // Tell the run-time the current values of mapping offset and scale.
777 GlobalValue *asan_mapping_offset =
778 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
779 ConstantInt::get(IntptrTy, MappingOffset),
780 kAsanMappingOffsetName);
781 // Read the global, otherwise it may be optimized away.
782 IRB.CreateLoad(asan_mapping_offset, true);
784 if (ClMappingScale) {
785 GlobalValue *asan_mapping_scale =
786 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
787 ConstantInt::get(IntptrTy, MappingScale),
788 kAsanMappingScaleName);
789 // Read the global, otherwise it may be optimized away.
790 IRB.CreateLoad(asan_mapping_scale, true);
793 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
798 bool AddressSanitizer::doFinalization(Module &M) {
799 // We transform the globals at the very end so that the optimization analysis
800 // works on the original globals.
802 return insertGlobalRedzones(M);
807 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
808 // For each NSObject descendant having a +load method, this method is invoked
809 // by the ObjC runtime before any of the static constructors is called.
810 // Therefore we need to instrument such methods with a call to __asan_init
811 // at the beginning in order to initialize our runtime before any access to
812 // the shadow memory.
813 // We cannot just ignore these methods, because they may call other
814 // instrumented functions.
815 if (F.getName().find(" load]") != std::string::npos) {
816 IRBuilder<> IRB(F.begin()->begin());
817 IRB.CreateCall(AsanInitFunction);
823 bool AddressSanitizer::runOnFunction(Function &F) {
824 if (BL->isIn(F)) return false;
825 if (&F == AsanCtorFunction) return false;
826 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
828 // If needed, insert __asan_init before checking for AddressSafety attr.
829 maybeInsertAsanInitAtFunctionEntry(F);
831 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
834 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
837 // We want to instrument every address only once per basic block (unless there
838 // are calls between uses).
839 SmallSet<Value*, 16> TempsToInstrument;
840 SmallVector<Instruction*, 16> ToInstrument;
841 SmallVector<Instruction*, 8> NoReturnCalls;
844 // Fill the set of memory operations to instrument.
845 for (Function::iterator FI = F.begin(), FE = F.end();
847 TempsToInstrument.clear();
848 int NumInsnsPerBB = 0;
849 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
851 if (LooksLikeCodeInBug11395(BI)) return false;
852 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
853 if (ClOpt && ClOptSameTemp) {
854 if (!TempsToInstrument.insert(Addr))
855 continue; // We've seen this temp in the current BB.
857 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
860 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
862 TempsToInstrument.clear();
863 if (CI->doesNotReturn()) {
864 NoReturnCalls.push_back(CI);
869 ToInstrument.push_back(BI);
871 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
877 int NumInstrumented = 0;
878 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
879 Instruction *Inst = ToInstrument[i];
880 if (ClDebugMin < 0 || ClDebugMax < 0 ||
881 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
882 if (isInterestingMemoryAccess(Inst, &IsWrite))
885 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
890 bool ChangedStack = poisonStackInFunction(F);
892 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
893 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
894 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
895 Instruction *CI = NoReturnCalls[i];
897 IRB.CreateCall(AsanHandleNoReturnFunc);
899 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
901 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
904 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
905 if (ShadowRedzoneSize == 1) return PoisonByte;
906 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
907 if (ShadowRedzoneSize == 4)
908 return (PoisonByte << 24) + (PoisonByte << 16) +
909 (PoisonByte << 8) + (PoisonByte);
910 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
913 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
916 size_t ShadowGranularity,
918 for (size_t i = 0; i < RedzoneSize;
919 i+= ShadowGranularity, Shadow++) {
920 if (i + ShadowGranularity <= Size) {
921 *Shadow = 0; // fully addressable
922 } else if (i >= Size) {
923 *Shadow = Magic; // unaddressable
925 *Shadow = Size - i; // first Size-i bytes are addressable
930 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
932 Value *ShadowBase, bool DoPoison) {
933 size_t ShadowRZSize = RedzoneSize >> MappingScale;
934 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
935 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
936 Type *RZPtrTy = PointerType::get(RZTy, 0);
938 Value *PoisonLeft = ConstantInt::get(RZTy,
939 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
940 Value *PoisonMid = ConstantInt::get(RZTy,
941 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
942 Value *PoisonRight = ConstantInt::get(RZTy,
943 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
945 // poison the first red zone.
946 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
948 // poison all other red zones.
949 uint64_t Pos = RedzoneSize;
950 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
951 AllocaInst *AI = AllocaVec[i];
952 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
953 uint64_t AlignedSize = getAlignedAllocaSize(AI);
954 assert(AlignedSize - SizeInBytes < RedzoneSize);
959 assert(ShadowBase->getType() == IntptrTy);
960 if (SizeInBytes < AlignedSize) {
961 // Poison the partial redzone at right
963 ShadowBase, ConstantInt::get(IntptrTy,
964 (Pos >> MappingScale) - ShadowRZSize));
965 size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
968 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
970 1ULL << MappingScale,
971 kAsanStackPartialRedzoneMagic);
973 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
974 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
977 // Poison the full redzone at right.
978 Ptr = IRB.CreateAdd(ShadowBase,
979 ConstantInt::get(IntptrTy, Pos >> MappingScale));
980 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
981 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
987 // Workaround for bug 11395: we don't want to instrument stack in functions
988 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
989 // FIXME: remove once the bug 11395 is fixed.
990 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
991 if (LongSize != 32) return false;
992 CallInst *CI = dyn_cast<CallInst>(I);
993 if (!CI || !CI->isInlineAsm()) return false;
994 if (CI->getNumArgOperands() <= 5) return false;
995 // We have inline assembly with quite a few arguments.
999 // Find all static Alloca instructions and put
1000 // poisoned red zones around all of them.
1001 // Then unpoison everything back before the function returns.
1003 // Stack poisoning does not play well with exception handling.
1004 // When an exception is thrown, we essentially bypass the code
1005 // that unpoisones the stack. This is why the run-time library has
1006 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1007 // stack in the interceptor. This however does not work inside the
1008 // actual function which catches the exception. Most likely because the
1009 // compiler hoists the load of the shadow value somewhere too high.
1010 // This causes asan to report a non-existing bug on 453.povray.
1011 // It sounds like an LLVM bug.
1012 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1013 if (!ClStack) return false;
1014 SmallVector<AllocaInst*, 16> AllocaVec;
1015 SmallVector<Instruction*, 8> RetVec;
1016 uint64_t TotalSize = 0;
1018 // Filter out Alloca instructions we want (and can) handle.
1019 // Collect Ret instructions.
1020 for (Function::iterator FI = F.begin(), FE = F.end();
1022 BasicBlock &BB = *FI;
1023 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1025 if (isa<ReturnInst>(BI)) {
1026 RetVec.push_back(BI);
1030 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1032 if (AI->isArrayAllocation()) continue;
1033 if (!AI->isStaticAlloca()) continue;
1034 if (!AI->getAllocatedType()->isSized()) continue;
1035 if (AI->getAlignment() > RedzoneSize) continue;
1036 AllocaVec.push_back(AI);
1037 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1038 TotalSize += AlignedSize;
1042 if (AllocaVec.empty()) return false;
1044 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
1046 bool DoStackMalloc = ClUseAfterReturn
1047 && LocalStackSize <= kMaxStackMallocSize;
1049 Instruction *InsBefore = AllocaVec[0];
1050 IRBuilder<> IRB(InsBefore);
1053 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1054 AllocaInst *MyAlloca =
1055 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1056 MyAlloca->setAlignment(RedzoneSize);
1057 assert(MyAlloca->isStaticAlloca());
1058 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1059 Value *LocalStackBase = OrigStackBase;
1061 if (DoStackMalloc) {
1062 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1063 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1066 // This string will be parsed by the run-time (DescribeStackAddress).
1067 SmallString<2048> StackDescriptionStorage;
1068 raw_svector_ostream StackDescription(StackDescriptionStorage);
1069 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1071 uint64_t Pos = RedzoneSize;
1072 // Replace Alloca instructions with base+offset.
1073 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1074 AllocaInst *AI = AllocaVec[i];
1075 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1076 StringRef Name = AI->getName();
1077 StackDescription << Pos << " " << SizeInBytes << " "
1078 << Name.size() << " " << Name << " ";
1079 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1080 assert((AlignedSize % RedzoneSize) == 0);
1081 AI->replaceAllUsesWith(
1083 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1085 Pos += AlignedSize + RedzoneSize;
1087 assert(Pos == LocalStackSize);
1089 // Write the Magic value and the frame description constant to the redzone.
1090 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1091 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1093 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1094 ConstantInt::get(IntptrTy, LongSize/8));
1095 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1096 GlobalVariable *StackDescriptionGlobal =
1097 createPrivateGlobalForString(*F.getParent(), StackDescription.str());
1098 GlobalsCreatedByAsan.insert(StackDescriptionGlobal);
1099 Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
1100 IRB.CreateStore(Description, BasePlus1);
1102 // Poison the stack redzones at the entry.
1103 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1104 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1106 // Unpoison the stack before all ret instructions.
1107 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1108 Instruction *Ret = RetVec[i];
1109 IRBuilder<> IRBRet(Ret);
1111 // Mark the current frame as retired.
1112 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1114 // Unpoison the stack.
1115 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1117 if (DoStackMalloc) {
1118 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1119 ConstantInt::get(IntptrTy, LocalStackSize),
1124 // We are done. Remove the old unused alloca instructions.
1125 for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
1126 AllocaVec[i]->eraseFromParent();