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";
72 static const char *kAsanGenPrefix = "__asan_gen_";
74 static const int kAsanStackLeftRedzoneMagic = 0xf1;
75 static const int kAsanStackMidRedzoneMagic = 0xf2;
76 static const int kAsanStackRightRedzoneMagic = 0xf3;
77 static const int kAsanStackPartialRedzoneMagic = 0xf4;
79 // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
80 static const size_t kNumberOfAccessSizes = 5;
82 // Command-line flags.
84 // This flag may need to be replaced with -f[no-]asan-reads.
85 static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
86 cl::desc("instrument read instructions"), cl::Hidden, cl::init(true));
87 static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
88 cl::desc("instrument write instructions"), cl::Hidden, cl::init(true));
89 static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
90 cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
91 cl::Hidden, cl::init(true));
92 static cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path",
93 cl::desc("use instrumentation with slow path for all accesses"),
94 cl::Hidden, cl::init(false));
95 // This flag limits the number of instructions to be instrumented
96 // in any given BB. Normally, this should be set to unlimited (INT_MAX),
97 // but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
99 static cl::opt<int> ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb",
101 cl::desc("maximal number of instructions to instrument in any given BB"),
103 // This flag may need to be replaced with -f[no]asan-stack.
104 static cl::opt<bool> ClStack("asan-stack",
105 cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
106 // This flag may need to be replaced with -f[no]asan-use-after-return.
107 static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
108 cl::desc("Check return-after-free"), cl::Hidden, cl::init(false));
109 // This flag may need to be replaced with -f[no]asan-globals.
110 static cl::opt<bool> ClGlobals("asan-globals",
111 cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
112 static cl::opt<bool> ClInitializers("asan-initialization-order",
113 cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false));
114 static cl::opt<bool> ClMemIntrin("asan-memintrin",
115 cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true));
116 // This flag may need to be replaced with -fasan-blacklist.
117 static cl::opt<std::string> ClBlackListFile("asan-blacklist",
118 cl::desc("File containing the list of functions to ignore "
119 "during instrumentation"), cl::Hidden);
121 // These flags allow to change the shadow mapping.
122 // The shadow mapping looks like
123 // Shadow = (Mem >> scale) + (1 << offset_log)
124 static cl::opt<int> ClMappingScale("asan-mapping-scale",
125 cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0));
126 static cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log",
127 cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1));
129 // Optimization flags. Not user visible, used mostly for testing
130 // and benchmarking the tool.
131 static cl::opt<bool> ClOpt("asan-opt",
132 cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true));
133 static cl::opt<bool> ClOptSameTemp("asan-opt-same-temp",
134 cl::desc("Instrument the same temp just once"), cl::Hidden,
136 static cl::opt<bool> ClOptGlobals("asan-opt-globals",
137 cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true));
140 static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
142 static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
143 cl::Hidden, cl::init(0));
144 static cl::opt<std::string> ClDebugFunc("asan-debug-func",
145 cl::Hidden, cl::desc("Debug func"));
146 static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
147 cl::Hidden, cl::init(-1));
148 static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
149 cl::Hidden, cl::init(-1));
152 /// A set of dynamically initialized globals extracted from metadata.
153 class SetOfDynamicallyInitializedGlobals {
155 void Init(Module& M) {
156 // Clang generates metadata identifying all dynamically initialized globals.
157 NamedMDNode *DynamicGlobals =
158 M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
161 for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
162 MDNode *MDN = DynamicGlobals->getOperand(i);
163 assert(MDN->getNumOperands() == 1);
164 Value *VG = MDN->getOperand(0);
165 // The optimizer may optimize away a global entirely, in which case we
166 // cannot instrument access to it.
169 DynInitGlobals.insert(cast<GlobalVariable>(VG));
172 bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
174 SmallSet<GlobalValue*, 32> DynInitGlobals;
178 /// AddressSanitizer: instrument the code in module to find memory bugs.
179 struct AddressSanitizer : public FunctionPass {
181 virtual const char *getPassName() const;
182 void instrumentMop(Instruction *I);
183 void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
184 Value *Addr, uint32_t TypeSize, bool IsWrite);
185 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
186 Value *ShadowValue, uint32_t TypeSize);
187 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
188 bool IsWrite, size_t AccessSizeIndex);
189 bool instrumentMemIntrinsic(MemIntrinsic *MI);
190 void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
192 Instruction *InsertBefore, bool IsWrite);
193 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
194 bool runOnFunction(Function &F);
195 void createInitializerPoisonCalls(Module &M,
196 Value *FirstAddr, Value *LastAddr);
197 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
198 bool poisonStackInFunction(Function &F);
199 virtual bool doInitialization(Module &M);
200 virtual bool doFinalization(Module &M);
201 bool insertGlobalRedzones(Module &M);
202 static char ID; // Pass identification, replacement for typeid
205 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
206 Type *Ty = AI->getAllocatedType();
207 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
210 uint64_t getAlignedSize(uint64_t SizeInBytes) {
211 return ((SizeInBytes + RedzoneSize - 1)
212 / RedzoneSize) * RedzoneSize;
214 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
215 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
216 return getAlignedSize(SizeInBytes);
219 Function *checkInterfaceFunction(Constant *FuncOrBitcast);
220 bool ShouldInstrumentGlobal(GlobalVariable *G);
221 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
222 Value *ShadowBase, bool DoPoison);
223 bool LooksLikeCodeInBug11395(Instruction *I);
224 void FindDynamicInitializers(Module &M);
228 uint64_t MappingOffset;
234 Function *AsanCtorFunction;
235 Function *AsanInitFunction;
236 Function *AsanStackMallocFunc, *AsanStackFreeFunc;
237 Function *AsanHandleNoReturnFunc;
238 Instruction *CtorInsertBefore;
239 OwningPtr<BlackList> BL;
240 // This array is indexed by AccessIsWrite and log2(AccessSize).
241 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
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,
275 static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
276 return G->getName().find(kAsanGenPrefix) == 0;
279 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
281 Shadow = IRB.CreateLShr(Shadow, MappingScale);
282 if (MappingOffset == 0)
284 // (Shadow >> scale) | offset
285 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
289 void AddressSanitizer::instrumentMemIntrinsicParam(
290 Instruction *OrigIns,
291 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
292 // Check the first byte.
294 IRBuilder<> IRB(InsertBefore);
295 instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
297 // Check the last byte.
299 IRBuilder<> IRB(InsertBefore);
300 Value *SizeMinusOne = IRB.CreateSub(
301 Size, ConstantInt::get(Size->getType(), 1));
302 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
303 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
304 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
305 instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
309 // Instrument memset/memmove/memcpy
310 bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
311 Value *Dst = MI->getDest();
312 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
313 Value *Src = MemTran ? MemTran->getSource() : 0;
314 Value *Length = MI->getLength();
316 Constant *ConstLength = dyn_cast<Constant>(Length);
317 Instruction *InsertBefore = MI;
319 if (ConstLength->isNullValue()) return false;
321 // The size is not a constant so it could be zero -- check at run-time.
322 IRBuilder<> IRB(InsertBefore);
324 Value *Cmp = IRB.CreateICmpNE(Length,
325 Constant::getNullValue(Length->getType()));
326 InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
329 instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
331 instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
335 // If I is an interesting memory access, return the PointerOperand
336 // and set IsWrite. Otherwise return NULL.
337 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
338 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
339 if (!ClInstrumentReads) return NULL;
341 return LI->getPointerOperand();
343 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
344 if (!ClInstrumentWrites) return NULL;
346 return SI->getPointerOperand();
348 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
349 if (!ClInstrumentAtomics) return NULL;
351 return RMW->getPointerOperand();
353 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
354 if (!ClInstrumentAtomics) return NULL;
356 return XCHG->getPointerOperand();
361 void AddressSanitizer::instrumentMop(Instruction *I) {
362 bool IsWrite = false;
363 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
365 if (ClOpt && ClOptGlobals) {
366 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
367 // If initialization order checking is disabled, a simple access to a
368 // dynamically initialized global is always valid.
371 // If a global variable does not have dynamic initialization we don't
372 // have to instrument it. However, if a global does not have initailizer
373 // at all, we assume it has dynamic initializer (in other TU).
374 if (G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G))
379 Type *OrigPtrTy = Addr->getType();
380 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
382 assert(OrigTy->isSized());
383 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
385 if (TypeSize != 8 && TypeSize != 16 &&
386 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
387 // Ignore all unusual sizes.
392 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
395 // Validate the result of Module::getOrInsertFunction called for an interface
396 // function of AddressSanitizer. If the instrumented module defines a function
397 // with the same name, their prototypes must match, otherwise
398 // getOrInsertFunction returns a bitcast.
399 Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
400 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
401 FuncOrBitcast->dump();
402 report_fatal_error("trying to redefine an AddressSanitizer "
403 "interface function");
406 Instruction *AddressSanitizer::generateCrashCode(
407 Instruction *InsertBefore, Value *Addr,
408 bool IsWrite, size_t AccessSizeIndex) {
409 IRBuilder<> IRB(InsertBefore);
410 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
412 // We don't do Call->setDoesNotReturn() because the BB already has
413 // UnreachableInst at the end.
414 // This EmptyAsm is required to avoid callback merge.
415 IRB.CreateCall(EmptyAsm);
419 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
422 size_t Granularity = 1 << MappingScale;
423 // Addr & (Granularity - 1)
424 Value *LastAccessedByte = IRB.CreateAnd(
425 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
426 // (Addr & (Granularity - 1)) + size - 1
427 if (TypeSize / 8 > 1)
428 LastAccessedByte = IRB.CreateAdd(
429 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
430 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
431 LastAccessedByte = IRB.CreateIntCast(
432 LastAccessedByte, ShadowValue->getType(), false);
433 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
434 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
437 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
438 IRBuilder<> &IRB, Value *Addr,
439 uint32_t TypeSize, bool IsWrite) {
440 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
442 Type *ShadowTy = IntegerType::get(
443 *C, std::max(8U, TypeSize >> MappingScale));
444 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
445 Value *ShadowPtr = memToShadow(AddrLong, IRB);
446 Value *CmpVal = Constant::getNullValue(ShadowTy);
447 Value *ShadowValue = IRB.CreateLoad(
448 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
450 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
451 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
452 size_t Granularity = 1 << MappingScale;
453 TerminatorInst *CrashTerm = 0;
455 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
456 TerminatorInst *CheckTerm =
457 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
458 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
459 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
460 IRB.SetInsertPoint(CheckTerm);
461 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
462 BasicBlock *CrashBlock =
463 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
464 CrashTerm = new UnreachableInst(*C, CrashBlock);
465 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
466 ReplaceInstWithInst(CheckTerm, NewTerm);
468 CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
472 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
473 Crash->setDebugLoc(OrigIns->getDebugLoc());
476 void AddressSanitizer::createInitializerPoisonCalls(Module &M,
479 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
480 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
481 // If that function is not present, this TU contains no globals, or they have
482 // all been optimized away
486 // Set up the arguments to our poison/unpoison functions.
487 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
489 // Declare our poisoning and unpoisoning functions.
490 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
491 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
492 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
493 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
494 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
495 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
497 // Add a call to poison all external globals before the given function starts.
498 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
500 // Add calls to unpoison all globals before each return instruction.
501 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
503 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
504 CallInst::Create(AsanUnpoisonGlobals, "", RI);
509 bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
510 Type *Ty = cast<PointerType>(G->getType())->getElementType();
511 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
513 if (BL->isIn(*G)) return false;
514 if (!Ty->isSized()) return false;
515 if (!G->hasInitializer()) return false;
516 if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
517 // Touch only those globals that will not be defined in other modules.
518 // Don't handle ODR type linkages since other modules may be built w/o asan.
519 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
520 G->getLinkage() != GlobalVariable::PrivateLinkage &&
521 G->getLinkage() != GlobalVariable::InternalLinkage)
523 // Two problems with thread-locals:
524 // - The address of the main thread's copy can't be computed at link-time.
525 // - Need to poison all copies, not just the main thread's one.
526 if (G->isThreadLocal())
528 // For now, just ignore this Alloca if the alignment is large.
529 if (G->getAlignment() > RedzoneSize) return false;
531 // Ignore all the globals with the names starting with "\01L_OBJC_".
532 // Many of those are put into the .cstring section. The linker compresses
533 // that section by removing the spare \0s after the string terminator, so
534 // our redzones get broken.
535 if ((G->getName().find("\01L_OBJC_") == 0) ||
536 (G->getName().find("\01l_OBJC_") == 0)) {
537 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
541 if (G->hasSection()) {
542 StringRef Section(G->getSection());
543 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
544 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
546 if ((Section.find("__OBJC,") == 0) ||
547 (Section.find("__DATA, __objc_") == 0)) {
548 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
551 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
552 // Constant CFString instances are compiled in the following way:
553 // -- the string buffer is emitted into
554 // __TEXT,__cstring,cstring_literals
555 // -- the constant NSConstantString structure referencing that buffer
556 // is placed into __DATA,__cfstring
557 // Therefore there's no point in placing redzones into __DATA,__cfstring.
558 // Moreover, it causes the linker to crash on OS X 10.7
559 if (Section.find("__DATA,__cfstring") == 0) {
560 DEBUG(dbgs() << "Ignoring CFString: " << *G);
568 // This function replaces all global variables with new variables that have
569 // trailing redzones. It also creates a function that poisons
570 // redzones and inserts this function into llvm.global_ctors.
571 bool AddressSanitizer::insertGlobalRedzones(Module &M) {
572 SmallVector<GlobalVariable *, 16> GlobalsToChange;
574 for (Module::GlobalListType::iterator G = M.global_begin(),
575 E = M.global_end(); G != E; ++G) {
576 if (ShouldInstrumentGlobal(G))
577 GlobalsToChange.push_back(G);
580 size_t n = GlobalsToChange.size();
581 if (n == 0) return false;
583 // A global is described by a structure
586 // size_t size_with_redzone;
588 // size_t has_dynamic_init;
589 // We initialize an array of such structures and pass it to a run-time call.
590 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
593 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
595 IRBuilder<> IRB(CtorInsertBefore);
597 // The addresses of the first and last dynamically initialized globals in
598 // this TU. Used in initialization order checking.
599 Value *FirstDynamic = 0, *LastDynamic = 0;
601 for (size_t i = 0; i < n; i++) {
602 GlobalVariable *G = GlobalsToChange[i];
603 PointerType *PtrTy = cast<PointerType>(G->getType());
604 Type *Ty = PtrTy->getElementType();
605 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
606 uint64_t RightRedzoneSize = RedzoneSize +
607 (RedzoneSize - (SizeInBytes % RedzoneSize));
608 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
609 // Determine whether this global should be poisoned in initialization.
610 bool GlobalHasDynamicInitializer =
611 DynamicallyInitializedGlobals.Contains(G);
612 // Don't check initialization order if this global is blacklisted.
613 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
615 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
616 Constant *NewInitializer = ConstantStruct::get(
617 NewTy, G->getInitializer(),
618 Constant::getNullValue(RightRedZoneTy), NULL);
620 SmallString<2048> DescriptionOfGlobal = G->getName();
621 DescriptionOfGlobal += " (";
622 DescriptionOfGlobal += M.getModuleIdentifier();
623 DescriptionOfGlobal += ")";
624 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
626 // Create a new global variable with enough space for a redzone.
627 GlobalVariable *NewGlobal = new GlobalVariable(
628 M, NewTy, G->isConstant(), G->getLinkage(),
629 NewInitializer, "", G, G->getThreadLocalMode());
630 NewGlobal->copyAttributesFrom(G);
631 NewGlobal->setAlignment(RedzoneSize);
634 Indices2[0] = IRB.getInt32(0);
635 Indices2[1] = IRB.getInt32(0);
637 G->replaceAllUsesWith(
638 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
639 NewGlobal->takeName(G);
640 G->eraseFromParent();
642 Initializers[i] = ConstantStruct::get(
644 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
645 ConstantInt::get(IntptrTy, SizeInBytes),
646 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
647 ConstantExpr::getPointerCast(Name, IntptrTy),
648 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
651 // Populate the first and last globals declared in this TU.
652 if (ClInitializers && GlobalHasDynamicInitializer) {
653 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
654 if (FirstDynamic == 0)
655 FirstDynamic = LastDynamic;
658 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
661 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
662 GlobalVariable *AllGlobals = new GlobalVariable(
663 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
664 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
666 // Create calls for poisoning before initializers run and unpoisoning after.
667 if (ClInitializers && FirstDynamic && LastDynamic)
668 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
670 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
671 kAsanRegisterGlobalsName, IRB.getVoidTy(),
672 IntptrTy, IntptrTy, NULL));
673 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
675 IRB.CreateCall2(AsanRegisterGlobals,
676 IRB.CreatePointerCast(AllGlobals, IntptrTy),
677 ConstantInt::get(IntptrTy, n));
679 // We also need to unregister globals at the end, e.g. when a shared library
681 Function *AsanDtorFunction = Function::Create(
682 FunctionType::get(Type::getVoidTy(*C), false),
683 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
684 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
685 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
686 Function *AsanUnregisterGlobals =
687 checkInterfaceFunction(M.getOrInsertFunction(
688 kAsanUnregisterGlobalsName,
689 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
690 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
692 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
693 IRB.CreatePointerCast(AllGlobals, IntptrTy),
694 ConstantInt::get(IntptrTy, n));
695 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
702 bool AddressSanitizer::doInitialization(Module &M) {
703 // Initialize the private fields. No one has accessed them before.
704 TD = getAnalysisIfAvailable<DataLayout>();
708 BL.reset(new BlackList(ClBlackListFile));
709 DynamicallyInitializedGlobals.Init(M);
711 C = &(M.getContext());
712 LongSize = TD->getPointerSizeInBits();
713 IntptrTy = Type::getIntNTy(*C, LongSize);
714 IntptrPtrTy = PointerType::get(IntptrTy, 0);
716 AsanCtorFunction = Function::Create(
717 FunctionType::get(Type::getVoidTy(*C), false),
718 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
719 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
720 CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
722 // call __asan_init in the module ctor.
723 IRBuilder<> IRB(CtorInsertBefore);
724 AsanInitFunction = checkInterfaceFunction(
725 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
726 AsanInitFunction->setLinkage(Function::ExternalLinkage);
727 IRB.CreateCall(AsanInitFunction);
729 // Create __asan_report* callbacks.
730 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
731 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
733 // IsWrite and TypeSize are encoded in the function name.
734 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
735 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
736 // If we are merging crash callbacks, they have two parameters.
737 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
738 checkInterfaceFunction(M.getOrInsertFunction(
739 FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
743 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
744 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
745 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
746 kAsanStackFreeName, IRB.getVoidTy(),
747 IntptrTy, IntptrTy, IntptrTy, NULL));
748 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
749 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
751 // We insert an empty inline asm after __asan_report* to avoid callback merge.
752 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
753 StringRef(""), StringRef(""),
754 /*hasSideEffects=*/true);
756 llvm::Triple targetTriple(M.getTargetTriple());
757 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
759 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
760 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
761 if (ClMappingOffsetLog >= 0) {
762 if (ClMappingOffsetLog == 0) {
766 MappingOffset = 1ULL << ClMappingOffsetLog;
769 MappingScale = kDefaultShadowScale;
770 if (ClMappingScale) {
771 MappingScale = ClMappingScale;
773 // Redzone used for stack and globals is at least 32 bytes.
774 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
775 RedzoneSize = std::max(32, (int)(1 << MappingScale));
778 if (ClMappingOffsetLog >= 0) {
779 // Tell the run-time the current values of mapping offset and scale.
780 GlobalValue *asan_mapping_offset =
781 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
782 ConstantInt::get(IntptrTy, MappingOffset),
783 kAsanMappingOffsetName);
784 // Read the global, otherwise it may be optimized away.
785 IRB.CreateLoad(asan_mapping_offset, true);
787 if (ClMappingScale) {
788 GlobalValue *asan_mapping_scale =
789 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
790 ConstantInt::get(IntptrTy, MappingScale),
791 kAsanMappingScaleName);
792 // Read the global, otherwise it may be optimized away.
793 IRB.CreateLoad(asan_mapping_scale, true);
796 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
801 bool AddressSanitizer::doFinalization(Module &M) {
802 // We transform the globals at the very end so that the optimization analysis
803 // works on the original globals.
805 return insertGlobalRedzones(M);
810 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
811 // For each NSObject descendant having a +load method, this method is invoked
812 // by the ObjC runtime before any of the static constructors is called.
813 // Therefore we need to instrument such methods with a call to __asan_init
814 // at the beginning in order to initialize our runtime before any access to
815 // the shadow memory.
816 // We cannot just ignore these methods, because they may call other
817 // instrumented functions.
818 if (F.getName().find(" load]") != std::string::npos) {
819 IRBuilder<> IRB(F.begin()->begin());
820 IRB.CreateCall(AsanInitFunction);
826 bool AddressSanitizer::runOnFunction(Function &F) {
827 if (BL->isIn(F)) return false;
828 if (&F == AsanCtorFunction) return false;
829 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
831 // If needed, insert __asan_init before checking for AddressSafety attr.
832 maybeInsertAsanInitAtFunctionEntry(F);
834 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
837 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
840 // We want to instrument every address only once per basic block (unless there
841 // are calls between uses).
842 SmallSet<Value*, 16> TempsToInstrument;
843 SmallVector<Instruction*, 16> ToInstrument;
844 SmallVector<Instruction*, 8> NoReturnCalls;
847 // Fill the set of memory operations to instrument.
848 for (Function::iterator FI = F.begin(), FE = F.end();
850 TempsToInstrument.clear();
851 int NumInsnsPerBB = 0;
852 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
854 if (LooksLikeCodeInBug11395(BI)) return false;
855 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
856 if (ClOpt && ClOptSameTemp) {
857 if (!TempsToInstrument.insert(Addr))
858 continue; // We've seen this temp in the current BB.
860 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
863 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
865 TempsToInstrument.clear();
866 if (CI->doesNotReturn()) {
867 NoReturnCalls.push_back(CI);
872 ToInstrument.push_back(BI);
874 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
880 int NumInstrumented = 0;
881 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
882 Instruction *Inst = ToInstrument[i];
883 if (ClDebugMin < 0 || ClDebugMax < 0 ||
884 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
885 if (isInterestingMemoryAccess(Inst, &IsWrite))
888 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
893 bool ChangedStack = poisonStackInFunction(F);
895 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
896 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
897 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
898 Instruction *CI = NoReturnCalls[i];
900 IRB.CreateCall(AsanHandleNoReturnFunc);
902 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
904 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
907 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
908 if (ShadowRedzoneSize == 1) return PoisonByte;
909 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
910 if (ShadowRedzoneSize == 4)
911 return (PoisonByte << 24) + (PoisonByte << 16) +
912 (PoisonByte << 8) + (PoisonByte);
913 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
916 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
919 size_t ShadowGranularity,
921 for (size_t i = 0; i < RedzoneSize;
922 i+= ShadowGranularity, Shadow++) {
923 if (i + ShadowGranularity <= Size) {
924 *Shadow = 0; // fully addressable
925 } else if (i >= Size) {
926 *Shadow = Magic; // unaddressable
928 *Shadow = Size - i; // first Size-i bytes are addressable
933 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
935 Value *ShadowBase, bool DoPoison) {
936 size_t ShadowRZSize = RedzoneSize >> MappingScale;
937 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
938 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
939 Type *RZPtrTy = PointerType::get(RZTy, 0);
941 Value *PoisonLeft = ConstantInt::get(RZTy,
942 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
943 Value *PoisonMid = ConstantInt::get(RZTy,
944 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
945 Value *PoisonRight = ConstantInt::get(RZTy,
946 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
948 // poison the first red zone.
949 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
951 // poison all other red zones.
952 uint64_t Pos = RedzoneSize;
953 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
954 AllocaInst *AI = AllocaVec[i];
955 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
956 uint64_t AlignedSize = getAlignedAllocaSize(AI);
957 assert(AlignedSize - SizeInBytes < RedzoneSize);
962 assert(ShadowBase->getType() == IntptrTy);
963 if (SizeInBytes < AlignedSize) {
964 // Poison the partial redzone at right
966 ShadowBase, ConstantInt::get(IntptrTy,
967 (Pos >> MappingScale) - ShadowRZSize));
968 size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
971 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
973 1ULL << MappingScale,
974 kAsanStackPartialRedzoneMagic);
976 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
977 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
980 // Poison the full redzone at right.
981 Ptr = IRB.CreateAdd(ShadowBase,
982 ConstantInt::get(IntptrTy, Pos >> MappingScale));
983 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
984 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
990 // Workaround for bug 11395: we don't want to instrument stack in functions
991 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
992 // FIXME: remove once the bug 11395 is fixed.
993 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
994 if (LongSize != 32) return false;
995 CallInst *CI = dyn_cast<CallInst>(I);
996 if (!CI || !CI->isInlineAsm()) return false;
997 if (CI->getNumArgOperands() <= 5) return false;
998 // We have inline assembly with quite a few arguments.
1002 // Find all static Alloca instructions and put
1003 // poisoned red zones around all of them.
1004 // Then unpoison everything back before the function returns.
1006 // Stack poisoning does not play well with exception handling.
1007 // When an exception is thrown, we essentially bypass the code
1008 // that unpoisones the stack. This is why the run-time library has
1009 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1010 // stack in the interceptor. This however does not work inside the
1011 // actual function which catches the exception. Most likely because the
1012 // compiler hoists the load of the shadow value somewhere too high.
1013 // This causes asan to report a non-existing bug on 453.povray.
1014 // It sounds like an LLVM bug.
1015 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1016 if (!ClStack) return false;
1017 SmallVector<AllocaInst*, 16> AllocaVec;
1018 SmallVector<Instruction*, 8> RetVec;
1019 uint64_t TotalSize = 0;
1021 // Filter out Alloca instructions we want (and can) handle.
1022 // Collect Ret instructions.
1023 for (Function::iterator FI = F.begin(), FE = F.end();
1025 BasicBlock &BB = *FI;
1026 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1028 if (isa<ReturnInst>(BI)) {
1029 RetVec.push_back(BI);
1033 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1035 if (AI->isArrayAllocation()) continue;
1036 if (!AI->isStaticAlloca()) continue;
1037 if (!AI->getAllocatedType()->isSized()) continue;
1038 if (AI->getAlignment() > RedzoneSize) continue;
1039 AllocaVec.push_back(AI);
1040 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1041 TotalSize += AlignedSize;
1045 if (AllocaVec.empty()) return false;
1047 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
1049 bool DoStackMalloc = ClUseAfterReturn
1050 && LocalStackSize <= kMaxStackMallocSize;
1052 Instruction *InsBefore = AllocaVec[0];
1053 IRBuilder<> IRB(InsBefore);
1056 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1057 AllocaInst *MyAlloca =
1058 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1059 MyAlloca->setAlignment(RedzoneSize);
1060 assert(MyAlloca->isStaticAlloca());
1061 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1062 Value *LocalStackBase = OrigStackBase;
1064 if (DoStackMalloc) {
1065 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1066 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1069 // This string will be parsed by the run-time (DescribeStackAddress).
1070 SmallString<2048> StackDescriptionStorage;
1071 raw_svector_ostream StackDescription(StackDescriptionStorage);
1072 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1074 uint64_t Pos = RedzoneSize;
1075 // Replace Alloca instructions with base+offset.
1076 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1077 AllocaInst *AI = AllocaVec[i];
1078 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1079 StringRef Name = AI->getName();
1080 StackDescription << Pos << " " << SizeInBytes << " "
1081 << Name.size() << " " << Name << " ";
1082 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1083 assert((AlignedSize % RedzoneSize) == 0);
1084 AI->replaceAllUsesWith(
1086 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1088 Pos += AlignedSize + RedzoneSize;
1090 assert(Pos == LocalStackSize);
1092 // Write the Magic value and the frame description constant to the redzone.
1093 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1094 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1096 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1097 ConstantInt::get(IntptrTy, LongSize/8));
1098 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1099 GlobalVariable *StackDescriptionGlobal =
1100 createPrivateGlobalForString(*F.getParent(), StackDescription.str());
1101 Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
1102 IRB.CreateStore(Description, BasePlus1);
1104 // Poison the stack redzones at the entry.
1105 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1106 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1108 // Unpoison the stack before all ret instructions.
1109 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1110 Instruction *Ret = RetVec[i];
1111 IRBuilder<> IRBRet(Ret);
1113 // Mark the current frame as retired.
1114 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1116 // Unpoison the stack.
1117 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1119 if (DoStackMalloc) {
1120 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1121 ConstantInt::get(IntptrTy, LocalStackSize),
1126 // We are done. Remove the old unused alloca instructions.
1127 for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
1128 AllocaVec[i]->eraseFromParent();