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/Target/TargetData.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));
152 /// An object of this type is created while instrumenting every function.
153 struct AsanFunctionContext {
154 AsanFunctionContext(Function &Function) : F(Function) { }
159 /// AddressSanitizer: instrument the code in module to find memory bugs.
160 struct AddressSanitizer : public ModulePass {
162 virtual const char *getPassName() const;
163 void instrumentMop(AsanFunctionContext &AFC, Instruction *I);
164 void instrumentAddress(AsanFunctionContext &AFC,
165 Instruction *OrigIns, IRBuilder<> &IRB,
166 Value *Addr, uint32_t TypeSize, bool IsWrite);
167 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
168 Value *ShadowValue, uint32_t TypeSize);
169 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
170 bool IsWrite, size_t AccessSizeIndex);
171 bool instrumentMemIntrinsic(AsanFunctionContext &AFC, MemIntrinsic *MI);
172 void instrumentMemIntrinsicParam(AsanFunctionContext &AFC,
173 Instruction *OrigIns, Value *Addr,
175 Instruction *InsertBefore, bool IsWrite);
176 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
177 bool handleFunction(Module &M, Function &F);
178 void createInitializerPoisonCalls(Module &M,
179 Value *FirstAddr, Value *LastAddr);
180 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
181 bool poisonStackInFunction(Module &M, Function &F);
182 virtual bool runOnModule(Module &M);
183 bool insertGlobalRedzones(Module &M);
184 static char ID; // Pass identification, replacement for typeid
187 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
188 Type *Ty = AI->getAllocatedType();
189 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
192 uint64_t getAlignedSize(uint64_t SizeInBytes) {
193 return ((SizeInBytes + RedzoneSize - 1)
194 / RedzoneSize) * RedzoneSize;
196 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
197 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
198 return getAlignedSize(SizeInBytes);
201 Function *checkInterfaceFunction(Constant *FuncOrBitcast);
202 bool ShouldInstrumentGlobal(GlobalVariable *G);
203 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
204 Value *ShadowBase, bool DoPoison);
205 bool LooksLikeCodeInBug11395(Instruction *I);
206 void FindDynamicInitializers(Module &M);
207 bool HasDynamicInitializer(GlobalVariable *G);
211 uint64_t MappingOffset;
217 Function *AsanCtorFunction;
218 Function *AsanInitFunction;
219 Instruction *CtorInsertBefore;
220 OwningPtr<BlackList> BL;
221 // This array is indexed by AccessIsWrite and log2(AccessSize).
222 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
224 SmallSet<GlobalValue*, 32> DynamicallyInitializedGlobals;
229 char AddressSanitizer::ID = 0;
230 INITIALIZE_PASS(AddressSanitizer, "asan",
231 "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
233 AddressSanitizer::AddressSanitizer() : ModulePass(ID) { }
234 ModulePass *llvm::createAddressSanitizerPass() {
235 return new AddressSanitizer();
238 const char *AddressSanitizer::getPassName() const {
239 return "AddressSanitizer";
242 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
243 size_t Res = CountTrailingZeros_32(TypeSize / 8);
244 assert(Res < kNumberOfAccessSizes);
248 // Create a constant for Str so that we can pass it to the run-time lib.
249 static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
250 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
251 return new GlobalVariable(M, StrConst->getType(), true,
252 GlobalValue::PrivateLinkage, StrConst, "");
255 // Split the basic block and insert an if-then code.
266 // ThenBlock block is created and its terminator is returned.
267 // If Unreachable, ThenBlock is terminated with UnreachableInst, otherwise
268 // it is terminated with BranchInst to Tail.
269 static TerminatorInst *splitBlockAndInsertIfThen(Value *Cmp, bool Unreachable) {
270 Instruction *SplitBefore = cast<Instruction>(Cmp)->getNextNode();
271 BasicBlock *Head = SplitBefore->getParent();
272 BasicBlock *Tail = Head->splitBasicBlock(SplitBefore);
273 TerminatorInst *HeadOldTerm = Head->getTerminator();
274 LLVMContext &C = Head->getParent()->getParent()->getContext();
275 BasicBlock *ThenBlock = BasicBlock::Create(C, "", Head->getParent(), Tail);
276 TerminatorInst *CheckTerm;
278 CheckTerm = new UnreachableInst(C, ThenBlock);
280 CheckTerm = BranchInst::Create(Tail, ThenBlock);
281 BranchInst *HeadNewTerm =
282 BranchInst::Create(/*ifTrue*/ThenBlock, /*ifFalse*/Tail, Cmp);
283 ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
287 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
289 Shadow = IRB.CreateLShr(Shadow, MappingScale);
290 if (MappingOffset == 0)
292 // (Shadow >> scale) | offset
293 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
297 void AddressSanitizer::instrumentMemIntrinsicParam(
298 AsanFunctionContext &AFC, Instruction *OrigIns,
299 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
300 // Check the first byte.
302 IRBuilder<> IRB(InsertBefore);
303 instrumentAddress(AFC, OrigIns, IRB, Addr, 8, IsWrite);
305 // Check the last byte.
307 IRBuilder<> IRB(InsertBefore);
308 Value *SizeMinusOne = IRB.CreateSub(
309 Size, ConstantInt::get(Size->getType(), 1));
310 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
311 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
312 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
313 instrumentAddress(AFC, OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
317 // Instrument memset/memmove/memcpy
318 bool AddressSanitizer::instrumentMemIntrinsic(AsanFunctionContext &AFC,
320 Value *Dst = MI->getDest();
321 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
322 Value *Src = MemTran ? MemTran->getSource() : 0;
323 Value *Length = MI->getLength();
325 Constant *ConstLength = dyn_cast<Constant>(Length);
326 Instruction *InsertBefore = MI;
328 if (ConstLength->isNullValue()) return false;
330 // The size is not a constant so it could be zero -- check at run-time.
331 IRBuilder<> IRB(InsertBefore);
333 Value *Cmp = IRB.CreateICmpNE(Length,
334 Constant::getNullValue(Length->getType()));
335 InsertBefore = splitBlockAndInsertIfThen(Cmp, false);
338 instrumentMemIntrinsicParam(AFC, MI, Dst, Length, InsertBefore, true);
340 instrumentMemIntrinsicParam(AFC, MI, Src, Length, InsertBefore, false);
344 // If I is an interesting memory access, return the PointerOperand
345 // and set IsWrite. Otherwise return NULL.
346 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
347 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
348 if (!ClInstrumentReads) return NULL;
350 return LI->getPointerOperand();
352 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
353 if (!ClInstrumentWrites) return NULL;
355 return SI->getPointerOperand();
357 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
358 if (!ClInstrumentAtomics) return NULL;
360 return RMW->getPointerOperand();
362 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
363 if (!ClInstrumentAtomics) return NULL;
365 return XCHG->getPointerOperand();
370 void AddressSanitizer::FindDynamicInitializers(Module& M) {
371 // Clang generates metadata identifying all dynamically initialized globals.
372 NamedMDNode *DynamicGlobals =
373 M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
376 for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
377 MDNode *MDN = DynamicGlobals->getOperand(i);
378 assert(MDN->getNumOperands() == 1);
379 Value *VG = MDN->getOperand(0);
380 // The optimizer may optimize away a global entirely, in which case we
381 // cannot instrument access to it.
385 GlobalVariable *G = cast<GlobalVariable>(VG);
386 DynamicallyInitializedGlobals.insert(G);
389 // Returns true if a global variable is initialized dynamically in this TU.
390 bool AddressSanitizer::HasDynamicInitializer(GlobalVariable *G) {
391 return DynamicallyInitializedGlobals.count(G);
394 void AddressSanitizer::instrumentMop(AsanFunctionContext &AFC, Instruction *I) {
396 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
398 if (ClOpt && ClOptGlobals) {
399 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
400 // If initialization order checking is disabled, a simple access to a
401 // dynamically initialized global is always valid.
404 // If a global variable does not have dynamic initialization we don't
405 // have to instrument it. However, if a global has external linkage, we
406 // assume it has dynamic initialization, as it may have an initializer
407 // in a different TU.
408 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
409 !HasDynamicInitializer(G))
414 Type *OrigPtrTy = Addr->getType();
415 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
417 assert(OrigTy->isSized());
418 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
420 if (TypeSize != 8 && TypeSize != 16 &&
421 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
422 // Ignore all unusual sizes.
427 instrumentAddress(AFC, I, IRB, Addr, TypeSize, IsWrite);
430 // Validate the result of Module::getOrInsertFunction called for an interface
431 // function of AddressSanitizer. If the instrumented module defines a function
432 // with the same name, their prototypes must match, otherwise
433 // getOrInsertFunction returns a bitcast.
434 Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
435 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
436 FuncOrBitcast->dump();
437 report_fatal_error("trying to redefine an AddressSanitizer "
438 "interface function");
441 Instruction *AddressSanitizer::generateCrashCode(
442 Instruction *InsertBefore, Value *Addr,
443 bool IsWrite, size_t AccessSizeIndex) {
444 IRBuilder<> IRB(InsertBefore);
445 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
447 // We don't do Call->setDoesNotReturn() because the BB already has
448 // UnreachableInst at the end.
449 // This EmptyAsm is required to avoid callback merge.
450 IRB.CreateCall(EmptyAsm);
454 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
457 size_t Granularity = 1 << MappingScale;
458 // Addr & (Granularity - 1)
459 Value *LastAccessedByte = IRB.CreateAnd(
460 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
461 // (Addr & (Granularity - 1)) + size - 1
462 if (TypeSize / 8 > 1)
463 LastAccessedByte = IRB.CreateAdd(
464 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
465 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
466 LastAccessedByte = IRB.CreateIntCast(
467 LastAccessedByte, ShadowValue->getType(), false);
468 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
469 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
472 void AddressSanitizer::instrumentAddress(AsanFunctionContext &AFC,
473 Instruction *OrigIns,
474 IRBuilder<> &IRB, Value *Addr,
475 uint32_t TypeSize, bool IsWrite) {
476 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
478 Type *ShadowTy = IntegerType::get(
479 *C, std::max(8U, TypeSize >> MappingScale));
480 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
481 Value *ShadowPtr = memToShadow(AddrLong, IRB);
482 Value *CmpVal = Constant::getNullValue(ShadowTy);
483 Value *ShadowValue = IRB.CreateLoad(
484 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
486 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
487 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
488 size_t Granularity = 1 << MappingScale;
489 TerminatorInst *CrashTerm = 0;
491 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
492 TerminatorInst *CheckTerm = splitBlockAndInsertIfThen(Cmp, false);
493 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
494 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
495 IRB.SetInsertPoint(CheckTerm);
496 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
497 BasicBlock *CrashBlock = BasicBlock::Create(*C, "", &AFC.F, NextBB);
498 CrashTerm = new UnreachableInst(*C, CrashBlock);
499 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
500 ReplaceInstWithInst(CheckTerm, NewTerm);
502 CrashTerm = splitBlockAndInsertIfThen(Cmp, true);
506 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
507 Crash->setDebugLoc(OrigIns->getDebugLoc());
510 void AddressSanitizer::createInitializerPoisonCalls(Module &M,
513 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
514 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
515 // If that function is not present, this TU contains no globals, or they have
516 // all been optimized away
520 // Set up the arguments to our poison/unpoison functions.
521 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
523 // Declare our poisoning and unpoisoning functions.
524 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
525 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
526 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
527 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
528 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
529 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
531 // Add a call to poison all external globals before the given function starts.
532 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
534 // Add calls to unpoison all globals before each return instruction.
535 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
537 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
538 CallInst::Create(AsanUnpoisonGlobals, "", RI);
543 bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
544 Type *Ty = cast<PointerType>(G->getType())->getElementType();
545 DEBUG(dbgs() << "GLOBAL: " << *G);
547 if (BL->isIn(*G)) return false;
548 if (!Ty->isSized()) return false;
549 if (!G->hasInitializer()) return false;
550 // Touch only those globals that will not be defined in other modules.
551 // Don't handle ODR type linkages since other modules may be built w/o asan.
552 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
553 G->getLinkage() != GlobalVariable::PrivateLinkage &&
554 G->getLinkage() != GlobalVariable::InternalLinkage)
556 // Two problems with thread-locals:
557 // - The address of the main thread's copy can't be computed at link-time.
558 // - Need to poison all copies, not just the main thread's one.
559 if (G->isThreadLocal())
561 // For now, just ignore this Alloca if the alignment is large.
562 if (G->getAlignment() > RedzoneSize) return false;
564 // Ignore all the globals with the names starting with "\01L_OBJC_".
565 // Many of those are put into the .cstring section. The linker compresses
566 // that section by removing the spare \0s after the string terminator, so
567 // our redzones get broken.
568 if ((G->getName().find("\01L_OBJC_") == 0) ||
569 (G->getName().find("\01l_OBJC_") == 0)) {
570 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
574 if (G->hasSection()) {
575 StringRef Section(G->getSection());
576 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
577 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
579 if ((Section.find("__OBJC,") == 0) ||
580 (Section.find("__DATA, __objc_") == 0)) {
581 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
584 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
585 // Constant CFString instances are compiled in the following way:
586 // -- the string buffer is emitted into
587 // __TEXT,__cstring,cstring_literals
588 // -- the constant NSConstantString structure referencing that buffer
589 // is placed into __DATA,__cfstring
590 // Therefore there's no point in placing redzones into __DATA,__cfstring.
591 // Moreover, it causes the linker to crash on OS X 10.7
592 if (Section.find("__DATA,__cfstring") == 0) {
593 DEBUG(dbgs() << "Ignoring CFString: " << *G);
601 // This function replaces all global variables with new variables that have
602 // trailing redzones. It also creates a function that poisons
603 // redzones and inserts this function into llvm.global_ctors.
604 bool AddressSanitizer::insertGlobalRedzones(Module &M) {
605 SmallVector<GlobalVariable *, 16> GlobalsToChange;
607 for (Module::GlobalListType::iterator G = M.global_begin(),
608 E = M.global_end(); G != E; ++G) {
609 if (ShouldInstrumentGlobal(G))
610 GlobalsToChange.push_back(G);
613 size_t n = GlobalsToChange.size();
614 if (n == 0) return false;
616 // A global is described by a structure
619 // size_t size_with_redzone;
621 // size_t has_dynamic_init;
622 // We initialize an array of such structures and pass it to a run-time call.
623 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
626 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
628 IRBuilder<> IRB(CtorInsertBefore);
631 FindDynamicInitializers(M);
633 // The addresses of the first and last dynamically initialized globals in
634 // this TU. Used in initialization order checking.
635 Value *FirstDynamic = 0, *LastDynamic = 0;
637 for (size_t i = 0; i < n; i++) {
638 GlobalVariable *G = GlobalsToChange[i];
639 PointerType *PtrTy = cast<PointerType>(G->getType());
640 Type *Ty = PtrTy->getElementType();
641 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
642 uint64_t RightRedzoneSize = RedzoneSize +
643 (RedzoneSize - (SizeInBytes % RedzoneSize));
644 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
645 // Determine whether this global should be poisoned in initialization.
646 bool GlobalHasDynamicInitializer = HasDynamicInitializer(G);
647 // Don't check initialization order if this global is blacklisted.
648 GlobalHasDynamicInitializer &= ! BL->isInInit(*G);
650 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
651 Constant *NewInitializer = ConstantStruct::get(
652 NewTy, G->getInitializer(),
653 Constant::getNullValue(RightRedZoneTy), NULL);
655 SmallString<2048> DescriptionOfGlobal = G->getName();
656 DescriptionOfGlobal += " (";
657 DescriptionOfGlobal += M.getModuleIdentifier();
658 DescriptionOfGlobal += ")";
659 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
661 // Create a new global variable with enough space for a redzone.
662 GlobalVariable *NewGlobal = new GlobalVariable(
663 M, NewTy, G->isConstant(), G->getLinkage(),
664 NewInitializer, "", G, G->getThreadLocalMode());
665 NewGlobal->copyAttributesFrom(G);
666 NewGlobal->setAlignment(RedzoneSize);
669 Indices2[0] = IRB.getInt32(0);
670 Indices2[1] = IRB.getInt32(0);
672 G->replaceAllUsesWith(
673 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
674 NewGlobal->takeName(G);
675 G->eraseFromParent();
677 Initializers[i] = ConstantStruct::get(
679 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
680 ConstantInt::get(IntptrTy, SizeInBytes),
681 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
682 ConstantExpr::getPointerCast(Name, IntptrTy),
683 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
686 // Populate the first and last globals declared in this TU.
687 if (ClInitializers && GlobalHasDynamicInitializer) {
688 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
689 if (FirstDynamic == 0)
690 FirstDynamic = LastDynamic;
693 DEBUG(dbgs() << "NEW GLOBAL:\n" << *NewGlobal);
696 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
697 GlobalVariable *AllGlobals = new GlobalVariable(
698 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
699 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
701 // Create calls for poisoning before initializers run and unpoisoning after.
702 if (ClInitializers && FirstDynamic && LastDynamic)
703 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
705 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
706 kAsanRegisterGlobalsName, IRB.getVoidTy(),
707 IntptrTy, IntptrTy, NULL));
708 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
710 IRB.CreateCall2(AsanRegisterGlobals,
711 IRB.CreatePointerCast(AllGlobals, IntptrTy),
712 ConstantInt::get(IntptrTy, n));
714 // We also need to unregister globals at the end, e.g. when a shared library
716 Function *AsanDtorFunction = Function::Create(
717 FunctionType::get(Type::getVoidTy(*C), false),
718 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
719 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
720 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
721 Function *AsanUnregisterGlobals =
722 checkInterfaceFunction(M.getOrInsertFunction(
723 kAsanUnregisterGlobalsName,
724 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
725 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
727 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
728 IRB.CreatePointerCast(AllGlobals, IntptrTy),
729 ConstantInt::get(IntptrTy, n));
730 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
737 bool AddressSanitizer::runOnModule(Module &M) {
738 // Initialize the private fields. No one has accessed them before.
739 TD = getAnalysisIfAvailable<TargetData>();
742 BL.reset(new BlackList(ClBlackListFile));
744 C = &(M.getContext());
745 LongSize = TD->getPointerSizeInBits();
746 IntptrTy = Type::getIntNTy(*C, LongSize);
747 IntptrPtrTy = PointerType::get(IntptrTy, 0);
749 AsanCtorFunction = Function::Create(
750 FunctionType::get(Type::getVoidTy(*C), false),
751 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
752 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
753 CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
755 // call __asan_init in the module ctor.
756 IRBuilder<> IRB(CtorInsertBefore);
757 AsanInitFunction = checkInterfaceFunction(
758 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
759 AsanInitFunction->setLinkage(Function::ExternalLinkage);
760 IRB.CreateCall(AsanInitFunction);
762 // Create __asan_report* callbacks.
763 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
764 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
766 // IsWrite and TypeSize are encoded in the function name.
767 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
768 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
769 // If we are merging crash callbacks, they have two parameters.
770 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] = cast<Function>(
771 M.getOrInsertFunction(FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
774 // We insert an empty inline asm after __asan_report* to avoid callback merge.
775 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
776 StringRef(""), StringRef(""),
777 /*hasSideEffects=*/true);
779 llvm::Triple targetTriple(M.getTargetTriple());
780 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
782 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
783 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
784 if (ClMappingOffsetLog >= 0) {
785 if (ClMappingOffsetLog == 0) {
789 MappingOffset = 1ULL << ClMappingOffsetLog;
792 MappingScale = kDefaultShadowScale;
793 if (ClMappingScale) {
794 MappingScale = ClMappingScale;
796 // Redzone used for stack and globals is at least 32 bytes.
797 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
798 RedzoneSize = std::max(32, (int)(1 << MappingScale));
803 Res |= insertGlobalRedzones(M);
805 if (ClMappingOffsetLog >= 0) {
806 // Tell the run-time the current values of mapping offset and scale.
807 GlobalValue *asan_mapping_offset =
808 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
809 ConstantInt::get(IntptrTy, MappingOffset),
810 kAsanMappingOffsetName);
811 // Read the global, otherwise it may be optimized away.
812 IRB.CreateLoad(asan_mapping_offset, true);
814 if (ClMappingScale) {
815 GlobalValue *asan_mapping_scale =
816 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
817 ConstantInt::get(IntptrTy, MappingScale),
818 kAsanMappingScaleName);
819 // Read the global, otherwise it may be optimized away.
820 IRB.CreateLoad(asan_mapping_scale, true);
824 for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
825 if (F->isDeclaration()) continue;
826 Res |= handleFunction(M, *F);
829 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
834 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
835 // For each NSObject descendant having a +load method, this method is invoked
836 // by the ObjC runtime before any of the static constructors is called.
837 // Therefore we need to instrument such methods with a call to __asan_init
838 // at the beginning in order to initialize our runtime before any access to
839 // the shadow memory.
840 // We cannot just ignore these methods, because they may call other
841 // instrumented functions.
842 if (F.getName().find(" load]") != std::string::npos) {
843 IRBuilder<> IRB(F.begin()->begin());
844 IRB.CreateCall(AsanInitFunction);
850 bool AddressSanitizer::handleFunction(Module &M, Function &F) {
851 if (BL->isIn(F)) return false;
852 if (&F == AsanCtorFunction) return false;
854 // If needed, insert __asan_init before checking for AddressSafety attr.
855 maybeInsertAsanInitAtFunctionEntry(F);
857 if (!F.hasFnAttr(Attribute::AddressSafety)) return false;
859 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
861 // We want to instrument every address only once per basic block
862 // (unless there are calls between uses).
863 SmallSet<Value*, 16> TempsToInstrument;
864 SmallVector<Instruction*, 16> ToInstrument;
865 SmallVector<Instruction*, 8> NoReturnCalls;
868 // Fill the set of memory operations to instrument.
869 for (Function::iterator FI = F.begin(), FE = F.end();
871 TempsToInstrument.clear();
872 int NumInsnsPerBB = 0;
873 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
875 if (LooksLikeCodeInBug11395(BI)) return false;
876 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
877 if (ClOpt && ClOptSameTemp) {
878 if (!TempsToInstrument.insert(Addr))
879 continue; // We've seen this temp in the current BB.
881 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
884 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
886 TempsToInstrument.clear();
887 if (CI->doesNotReturn()) {
888 NoReturnCalls.push_back(CI);
893 ToInstrument.push_back(BI);
895 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
900 AsanFunctionContext AFC(F);
903 int NumInstrumented = 0;
904 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
905 Instruction *Inst = ToInstrument[i];
906 if (ClDebugMin < 0 || ClDebugMax < 0 ||
907 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
908 if (isInterestingMemoryAccess(Inst, &IsWrite))
909 instrumentMop(AFC, Inst);
911 instrumentMemIntrinsic(AFC, cast<MemIntrinsic>(Inst));
918 bool ChangedStack = poisonStackInFunction(M, F);
920 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
921 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
922 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
923 Instruction *CI = NoReturnCalls[i];
925 IRB.CreateCall(M.getOrInsertFunction(kAsanHandleNoReturnName,
926 IRB.getVoidTy(), NULL));
929 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
932 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
933 if (ShadowRedzoneSize == 1) return PoisonByte;
934 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
935 if (ShadowRedzoneSize == 4)
936 return (PoisonByte << 24) + (PoisonByte << 16) +
937 (PoisonByte << 8) + (PoisonByte);
938 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
941 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
944 size_t ShadowGranularity,
946 for (size_t i = 0; i < RedzoneSize;
947 i+= ShadowGranularity, Shadow++) {
948 if (i + ShadowGranularity <= Size) {
949 *Shadow = 0; // fully addressable
950 } else if (i >= Size) {
951 *Shadow = Magic; // unaddressable
953 *Shadow = Size - i; // first Size-i bytes are addressable
958 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
960 Value *ShadowBase, bool DoPoison) {
961 size_t ShadowRZSize = RedzoneSize >> MappingScale;
962 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
963 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
964 Type *RZPtrTy = PointerType::get(RZTy, 0);
966 Value *PoisonLeft = ConstantInt::get(RZTy,
967 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
968 Value *PoisonMid = ConstantInt::get(RZTy,
969 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
970 Value *PoisonRight = ConstantInt::get(RZTy,
971 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
973 // poison the first red zone.
974 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
976 // poison all other red zones.
977 uint64_t Pos = RedzoneSize;
978 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
979 AllocaInst *AI = AllocaVec[i];
980 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
981 uint64_t AlignedSize = getAlignedAllocaSize(AI);
982 assert(AlignedSize - SizeInBytes < RedzoneSize);
987 assert(ShadowBase->getType() == IntptrTy);
988 if (SizeInBytes < AlignedSize) {
989 // Poison the partial redzone at right
991 ShadowBase, ConstantInt::get(IntptrTy,
992 (Pos >> MappingScale) - ShadowRZSize));
993 size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
996 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
998 1ULL << MappingScale,
999 kAsanStackPartialRedzoneMagic);
1001 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
1002 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1005 // Poison the full redzone at right.
1006 Ptr = IRB.CreateAdd(ShadowBase,
1007 ConstantInt::get(IntptrTy, Pos >> MappingScale));
1008 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
1009 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1015 // Workaround for bug 11395: we don't want to instrument stack in functions
1016 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
1017 // FIXME: remove once the bug 11395 is fixed.
1018 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
1019 if (LongSize != 32) return false;
1020 CallInst *CI = dyn_cast<CallInst>(I);
1021 if (!CI || !CI->isInlineAsm()) return false;
1022 if (CI->getNumArgOperands() <= 5) return false;
1023 // We have inline assembly with quite a few arguments.
1027 // Find all static Alloca instructions and put
1028 // poisoned red zones around all of them.
1029 // Then unpoison everything back before the function returns.
1031 // Stack poisoning does not play well with exception handling.
1032 // When an exception is thrown, we essentially bypass the code
1033 // that unpoisones the stack. This is why the run-time library has
1034 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1035 // stack in the interceptor. This however does not work inside the
1036 // actual function which catches the exception. Most likely because the
1037 // compiler hoists the load of the shadow value somewhere too high.
1038 // This causes asan to report a non-existing bug on 453.povray.
1039 // It sounds like an LLVM bug.
1040 bool AddressSanitizer::poisonStackInFunction(Module &M, Function &F) {
1041 if (!ClStack) return false;
1042 SmallVector<AllocaInst*, 16> AllocaVec;
1043 SmallVector<Instruction*, 8> RetVec;
1044 uint64_t TotalSize = 0;
1046 // Filter out Alloca instructions we want (and can) handle.
1047 // Collect Ret instructions.
1048 for (Function::iterator FI = F.begin(), FE = F.end();
1050 BasicBlock &BB = *FI;
1051 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1053 if (isa<ReturnInst>(BI)) {
1054 RetVec.push_back(BI);
1058 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1060 if (AI->isArrayAllocation()) continue;
1061 if (!AI->isStaticAlloca()) continue;
1062 if (!AI->getAllocatedType()->isSized()) continue;
1063 if (AI->getAlignment() > RedzoneSize) continue;
1064 AllocaVec.push_back(AI);
1065 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1066 TotalSize += AlignedSize;
1070 if (AllocaVec.empty()) return false;
1072 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
1074 bool DoStackMalloc = ClUseAfterReturn
1075 && LocalStackSize <= kMaxStackMallocSize;
1077 Instruction *InsBefore = AllocaVec[0];
1078 IRBuilder<> IRB(InsBefore);
1081 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1082 AllocaInst *MyAlloca =
1083 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1084 MyAlloca->setAlignment(RedzoneSize);
1085 assert(MyAlloca->isStaticAlloca());
1086 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1087 Value *LocalStackBase = OrigStackBase;
1089 if (DoStackMalloc) {
1090 Value *AsanStackMallocFunc = M.getOrInsertFunction(
1091 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL);
1092 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1093 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1096 // This string will be parsed by the run-time (DescribeStackAddress).
1097 SmallString<2048> StackDescriptionStorage;
1098 raw_svector_ostream StackDescription(StackDescriptionStorage);
1099 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1101 uint64_t Pos = RedzoneSize;
1102 // Replace Alloca instructions with base+offset.
1103 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1104 AllocaInst *AI = AllocaVec[i];
1105 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1106 StringRef Name = AI->getName();
1107 StackDescription << Pos << " " << SizeInBytes << " "
1108 << Name.size() << " " << Name << " ";
1109 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1110 assert((AlignedSize % RedzoneSize) == 0);
1111 AI->replaceAllUsesWith(
1113 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1115 Pos += AlignedSize + RedzoneSize;
1117 assert(Pos == LocalStackSize);
1119 // Write the Magic value and the frame description constant to the redzone.
1120 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1121 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1123 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1124 ConstantInt::get(IntptrTy, LongSize/8));
1125 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1126 Value *Description = IRB.CreatePointerCast(
1127 createPrivateGlobalForString(M, StackDescription.str()),
1129 IRB.CreateStore(Description, BasePlus1);
1131 // Poison the stack redzones at the entry.
1132 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1133 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1135 Value *AsanStackFreeFunc = NULL;
1136 if (DoStackMalloc) {
1137 AsanStackFreeFunc = M.getOrInsertFunction(
1138 kAsanStackFreeName, IRB.getVoidTy(),
1139 IntptrTy, IntptrTy, IntptrTy, NULL);
1142 // Unpoison the stack before all ret instructions.
1143 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1144 Instruction *Ret = RetVec[i];
1145 IRBuilder<> IRBRet(Ret);
1147 // Mark the current frame as retired.
1148 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1150 // Unpoison the stack.
1151 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1153 if (DoStackMalloc) {
1154 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1155 ConstantInt::get(IntptrTy, LocalStackSize),