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;
177 static int MappingScale() {
178 return ClMappingScale ? ClMappingScale : kDefaultShadowScale;
181 static size_t RedzoneSize() {
182 // Redzone used for stack and globals is at least 32 bytes.
183 // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
184 return std::max(32U, 1U << MappingScale());
187 /// AddressSanitizer: instrument the code in module to find memory bugs.
188 struct AddressSanitizer : public FunctionPass {
190 virtual const char *getPassName() const;
191 void instrumentMop(Instruction *I);
192 void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
193 Value *Addr, uint32_t TypeSize, bool IsWrite);
194 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
195 Value *ShadowValue, uint32_t TypeSize);
196 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
197 bool IsWrite, size_t AccessSizeIndex);
198 bool instrumentMemIntrinsic(MemIntrinsic *MI);
199 void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
201 Instruction *InsertBefore, bool IsWrite);
202 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
203 bool runOnFunction(Function &F);
204 void createInitializerPoisonCalls(Module &M,
205 Value *FirstAddr, Value *LastAddr);
206 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
207 bool poisonStackInFunction(Function &F);
208 virtual bool doInitialization(Module &M);
209 virtual bool doFinalization(Module &M);
210 static char ID; // Pass identification, replacement for typeid
213 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
214 Type *Ty = AI->getAllocatedType();
215 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
218 uint64_t getAlignedSize(uint64_t SizeInBytes) {
219 size_t RZ = RedzoneSize();
220 return ((SizeInBytes + RZ - 1) / RZ) * RZ;
222 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
223 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
224 return getAlignedSize(SizeInBytes);
227 bool ShouldInstrumentGlobal(GlobalVariable *G);
228 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
229 Value *ShadowBase, bool DoPoison);
230 bool LooksLikeCodeInBug11395(Instruction *I);
231 void FindDynamicInitializers(Module &M);
235 uint64_t MappingOffset;
239 Function *AsanCtorFunction;
240 Function *AsanInitFunction;
241 Function *AsanStackMallocFunc, *AsanStackFreeFunc;
242 Function *AsanHandleNoReturnFunc;
243 OwningPtr<BlackList> BL;
244 // This array is indexed by AccessIsWrite and log2(AccessSize).
245 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
247 SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
250 // FIXME: inherit this from ModulePass and actually use it as a ModulePass.
251 class AddressSanitizerCreateGlobalRedzonesPass {
253 bool runOnModule(Module &M, DataLayout *TD);
255 bool ShouldInstrumentGlobal(GlobalVariable *G);
256 void createInitializerPoisonCalls(Module &M, Value *FirstAddr,
259 OwningPtr<BlackList> BL;
260 SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
267 char AddressSanitizer::ID = 0;
268 INITIALIZE_PASS(AddressSanitizer, "asan",
269 "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
271 AddressSanitizer::AddressSanitizer() : FunctionPass(ID) { }
272 FunctionPass *llvm::createAddressSanitizerPass() {
273 return new AddressSanitizer();
276 const char *AddressSanitizer::getPassName() const {
277 return "AddressSanitizer";
280 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
281 size_t Res = CountTrailingZeros_32(TypeSize / 8);
282 assert(Res < kNumberOfAccessSizes);
286 // Create a constant for Str so that we can pass it to the run-time lib.
287 static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
288 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
289 return new GlobalVariable(M, StrConst->getType(), true,
290 GlobalValue::PrivateLinkage, StrConst,
294 static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
295 return G->getName().find(kAsanGenPrefix) == 0;
298 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
300 Shadow = IRB.CreateLShr(Shadow, MappingScale());
301 if (MappingOffset == 0)
303 // (Shadow >> scale) | offset
304 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
308 void AddressSanitizer::instrumentMemIntrinsicParam(
309 Instruction *OrigIns,
310 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
311 // Check the first byte.
313 IRBuilder<> IRB(InsertBefore);
314 instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
316 // Check the last byte.
318 IRBuilder<> IRB(InsertBefore);
319 Value *SizeMinusOne = IRB.CreateSub(
320 Size, ConstantInt::get(Size->getType(), 1));
321 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
322 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
323 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
324 instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
328 // Instrument memset/memmove/memcpy
329 bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
330 Value *Dst = MI->getDest();
331 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
332 Value *Src = MemTran ? MemTran->getSource() : 0;
333 Value *Length = MI->getLength();
335 Constant *ConstLength = dyn_cast<Constant>(Length);
336 Instruction *InsertBefore = MI;
338 if (ConstLength->isNullValue()) return false;
340 // The size is not a constant so it could be zero -- check at run-time.
341 IRBuilder<> IRB(InsertBefore);
343 Value *Cmp = IRB.CreateICmpNE(Length,
344 Constant::getNullValue(Length->getType()));
345 InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
348 instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
350 instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
354 // If I is an interesting memory access, return the PointerOperand
355 // and set IsWrite. Otherwise return NULL.
356 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
357 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
358 if (!ClInstrumentReads) return NULL;
360 return LI->getPointerOperand();
362 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
363 if (!ClInstrumentWrites) return NULL;
365 return SI->getPointerOperand();
367 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
368 if (!ClInstrumentAtomics) return NULL;
370 return RMW->getPointerOperand();
372 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
373 if (!ClInstrumentAtomics) return NULL;
375 return XCHG->getPointerOperand();
380 void AddressSanitizer::instrumentMop(Instruction *I) {
381 bool IsWrite = false;
382 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
384 if (ClOpt && ClOptGlobals) {
385 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
386 // If initialization order checking is disabled, a simple access to a
387 // dynamically initialized global is always valid.
390 // If a global variable does not have dynamic initialization we don't
391 // have to instrument it. However, if a global does not have initailizer
392 // at all, we assume it has dynamic initializer (in other TU).
393 if (G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G))
398 Type *OrigPtrTy = Addr->getType();
399 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
401 assert(OrigTy->isSized());
402 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
404 if (TypeSize != 8 && TypeSize != 16 &&
405 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
406 // Ignore all unusual sizes.
411 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
414 // Validate the result of Module::getOrInsertFunction called for an interface
415 // function of AddressSanitizer. If the instrumented module defines a function
416 // with the same name, their prototypes must match, otherwise
417 // getOrInsertFunction returns a bitcast.
418 static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
419 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
420 FuncOrBitcast->dump();
421 report_fatal_error("trying to redefine an AddressSanitizer "
422 "interface function");
425 Instruction *AddressSanitizer::generateCrashCode(
426 Instruction *InsertBefore, Value *Addr,
427 bool IsWrite, size_t AccessSizeIndex) {
428 IRBuilder<> IRB(InsertBefore);
429 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
431 // We don't do Call->setDoesNotReturn() because the BB already has
432 // UnreachableInst at the end.
433 // This EmptyAsm is required to avoid callback merge.
434 IRB.CreateCall(EmptyAsm);
438 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
441 size_t Granularity = 1 << MappingScale();
442 // Addr & (Granularity - 1)
443 Value *LastAccessedByte = IRB.CreateAnd(
444 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
445 // (Addr & (Granularity - 1)) + size - 1
446 if (TypeSize / 8 > 1)
447 LastAccessedByte = IRB.CreateAdd(
448 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
449 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
450 LastAccessedByte = IRB.CreateIntCast(
451 LastAccessedByte, ShadowValue->getType(), false);
452 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
453 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
456 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
457 IRBuilder<> &IRB, Value *Addr,
458 uint32_t TypeSize, bool IsWrite) {
459 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
461 Type *ShadowTy = IntegerType::get(
462 *C, std::max(8U, TypeSize >> MappingScale()));
463 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
464 Value *ShadowPtr = memToShadow(AddrLong, IRB);
465 Value *CmpVal = Constant::getNullValue(ShadowTy);
466 Value *ShadowValue = IRB.CreateLoad(
467 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
469 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
470 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
471 size_t Granularity = 1 << MappingScale();
472 TerminatorInst *CrashTerm = 0;
474 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
475 TerminatorInst *CheckTerm =
476 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
477 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
478 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
479 IRB.SetInsertPoint(CheckTerm);
480 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
481 BasicBlock *CrashBlock =
482 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
483 CrashTerm = new UnreachableInst(*C, CrashBlock);
484 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
485 ReplaceInstWithInst(CheckTerm, NewTerm);
487 CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
491 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
492 Crash->setDebugLoc(OrigIns->getDebugLoc());
495 void AddressSanitizerCreateGlobalRedzonesPass::createInitializerPoisonCalls(
496 Module &M, Value *FirstAddr, Value *LastAddr) {
497 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
498 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
499 // If that function is not present, this TU contains no globals, or they have
500 // all been optimized away
504 // Set up the arguments to our poison/unpoison functions.
505 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
507 // Declare our poisoning and unpoisoning functions.
508 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
509 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
510 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
511 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
512 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
513 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
515 // Add a call to poison all external globals before the given function starts.
516 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
518 // Add calls to unpoison all globals before each return instruction.
519 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
521 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
522 CallInst::Create(AsanUnpoisonGlobals, "", RI);
527 bool AddressSanitizerCreateGlobalRedzonesPass::ShouldInstrumentGlobal(
529 Type *Ty = cast<PointerType>(G->getType())->getElementType();
530 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
532 if (BL->isIn(*G)) return false;
533 if (!Ty->isSized()) return false;
534 if (!G->hasInitializer()) return false;
535 if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
536 // Touch only those globals that will not be defined in other modules.
537 // Don't handle ODR type linkages since other modules may be built w/o asan.
538 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
539 G->getLinkage() != GlobalVariable::PrivateLinkage &&
540 G->getLinkage() != GlobalVariable::InternalLinkage)
542 // Two problems with thread-locals:
543 // - The address of the main thread's copy can't be computed at link-time.
544 // - Need to poison all copies, not just the main thread's one.
545 if (G->isThreadLocal())
547 // For now, just ignore this Alloca if the alignment is large.
548 if (G->getAlignment() > RedzoneSize()) return false;
550 // Ignore all the globals with the names starting with "\01L_OBJC_".
551 // Many of those are put into the .cstring section. The linker compresses
552 // that section by removing the spare \0s after the string terminator, so
553 // our redzones get broken.
554 if ((G->getName().find("\01L_OBJC_") == 0) ||
555 (G->getName().find("\01l_OBJC_") == 0)) {
556 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
560 if (G->hasSection()) {
561 StringRef Section(G->getSection());
562 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
563 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
565 if ((Section.find("__OBJC,") == 0) ||
566 (Section.find("__DATA, __objc_") == 0)) {
567 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
570 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
571 // Constant CFString instances are compiled in the following way:
572 // -- the string buffer is emitted into
573 // __TEXT,__cstring,cstring_literals
574 // -- the constant NSConstantString structure referencing that buffer
575 // is placed into __DATA,__cfstring
576 // Therefore there's no point in placing redzones into __DATA,__cfstring.
577 // Moreover, it causes the linker to crash on OS X 10.7
578 if (Section.find("__DATA,__cfstring") == 0) {
579 DEBUG(dbgs() << "Ignoring CFString: " << *G);
587 // This function replaces all global variables with new variables that have
588 // trailing redzones. It also creates a function that poisons
589 // redzones and inserts this function into llvm.global_ctors.
590 bool AddressSanitizerCreateGlobalRedzonesPass::runOnModule(Module &M,
592 BL.reset(new BlackList(ClBlackListFile));
593 DynamicallyInitializedGlobals.Init(M);
594 C = &(M.getContext());
595 IntptrTy = Type::getIntNTy(*C, TD->getPointerSizeInBits());
597 SmallVector<GlobalVariable *, 16> GlobalsToChange;
599 for (Module::GlobalListType::iterator G = M.global_begin(),
600 E = M.global_end(); G != E; ++G) {
601 if (ShouldInstrumentGlobal(G))
602 GlobalsToChange.push_back(G);
605 size_t n = GlobalsToChange.size();
606 if (n == 0) return false;
608 // A global is described by a structure
611 // size_t size_with_redzone;
613 // size_t has_dynamic_init;
614 // We initialize an array of such structures and pass it to a run-time call.
615 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
618 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
621 Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
623 IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
625 // The addresses of the first and last dynamically initialized globals in
626 // this TU. Used in initialization order checking.
627 Value *FirstDynamic = 0, *LastDynamic = 0;
629 for (size_t i = 0; i < n; i++) {
630 GlobalVariable *G = GlobalsToChange[i];
631 PointerType *PtrTy = cast<PointerType>(G->getType());
632 Type *Ty = PtrTy->getElementType();
633 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
634 size_t RZ = RedzoneSize();
635 uint64_t RightRedzoneSize = RZ + (RZ - (SizeInBytes % RZ));
636 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
637 // Determine whether this global should be poisoned in initialization.
638 bool GlobalHasDynamicInitializer =
639 DynamicallyInitializedGlobals.Contains(G);
640 // Don't check initialization order if this global is blacklisted.
641 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
643 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
644 Constant *NewInitializer = ConstantStruct::get(
645 NewTy, G->getInitializer(),
646 Constant::getNullValue(RightRedZoneTy), NULL);
648 SmallString<2048> DescriptionOfGlobal = G->getName();
649 DescriptionOfGlobal += " (";
650 DescriptionOfGlobal += M.getModuleIdentifier();
651 DescriptionOfGlobal += ")";
652 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
654 // Create a new global variable with enough space for a redzone.
655 GlobalVariable *NewGlobal = new GlobalVariable(
656 M, NewTy, G->isConstant(), G->getLinkage(),
657 NewInitializer, "", G, G->getThreadLocalMode());
658 NewGlobal->copyAttributesFrom(G);
659 NewGlobal->setAlignment(RZ);
662 Indices2[0] = IRB.getInt32(0);
663 Indices2[1] = IRB.getInt32(0);
665 G->replaceAllUsesWith(
666 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
667 NewGlobal->takeName(G);
668 G->eraseFromParent();
670 Initializers[i] = ConstantStruct::get(
672 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
673 ConstantInt::get(IntptrTy, SizeInBytes),
674 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
675 ConstantExpr::getPointerCast(Name, IntptrTy),
676 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
679 // Populate the first and last globals declared in this TU.
680 if (ClInitializers && GlobalHasDynamicInitializer) {
681 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
682 if (FirstDynamic == 0)
683 FirstDynamic = LastDynamic;
686 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
689 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
690 GlobalVariable *AllGlobals = new GlobalVariable(
691 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
692 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
694 // Create calls for poisoning before initializers run and unpoisoning after.
695 if (ClInitializers && FirstDynamic && LastDynamic)
696 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
698 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
699 kAsanRegisterGlobalsName, IRB.getVoidTy(),
700 IntptrTy, IntptrTy, NULL));
701 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
703 IRB.CreateCall2(AsanRegisterGlobals,
704 IRB.CreatePointerCast(AllGlobals, IntptrTy),
705 ConstantInt::get(IntptrTy, n));
707 // We also need to unregister globals at the end, e.g. when a shared library
709 Function *AsanDtorFunction = Function::Create(
710 FunctionType::get(Type::getVoidTy(*C), false),
711 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
712 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
713 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
714 Function *AsanUnregisterGlobals =
715 checkInterfaceFunction(M.getOrInsertFunction(
716 kAsanUnregisterGlobalsName,
717 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
718 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
720 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
721 IRB.CreatePointerCast(AllGlobals, IntptrTy),
722 ConstantInt::get(IntptrTy, n));
723 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
730 bool AddressSanitizer::doInitialization(Module &M) {
731 // Initialize the private fields. No one has accessed them before.
732 TD = getAnalysisIfAvailable<DataLayout>();
736 BL.reset(new BlackList(ClBlackListFile));
737 DynamicallyInitializedGlobals.Init(M);
739 C = &(M.getContext());
740 LongSize = TD->getPointerSizeInBits();
741 IntptrTy = Type::getIntNTy(*C, LongSize);
742 IntptrPtrTy = PointerType::get(IntptrTy, 0);
744 AsanCtorFunction = Function::Create(
745 FunctionType::get(Type::getVoidTy(*C), false),
746 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
747 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
748 // call __asan_init in the module ctor.
749 IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
750 AsanInitFunction = checkInterfaceFunction(
751 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
752 AsanInitFunction->setLinkage(Function::ExternalLinkage);
753 IRB.CreateCall(AsanInitFunction);
755 // Create __asan_report* callbacks.
756 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
757 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
759 // IsWrite and TypeSize are encoded in the function name.
760 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
761 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
762 // If we are merging crash callbacks, they have two parameters.
763 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
764 checkInterfaceFunction(M.getOrInsertFunction(
765 FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
769 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
770 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
771 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
772 kAsanStackFreeName, IRB.getVoidTy(),
773 IntptrTy, IntptrTy, IntptrTy, NULL));
774 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
775 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
777 // We insert an empty inline asm after __asan_report* to avoid callback merge.
778 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
779 StringRef(""), StringRef(""),
780 /*hasSideEffects=*/true);
782 llvm::Triple targetTriple(M.getTargetTriple());
783 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
785 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
786 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
787 if (ClMappingOffsetLog >= 0) {
788 if (ClMappingOffsetLog == 0) {
792 MappingOffset = 1ULL << ClMappingOffsetLog;
797 if (ClMappingOffsetLog >= 0) {
798 // Tell the run-time the current values of mapping offset and scale.
799 GlobalValue *asan_mapping_offset =
800 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
801 ConstantInt::get(IntptrTy, MappingOffset),
802 kAsanMappingOffsetName);
803 // Read the global, otherwise it may be optimized away.
804 IRB.CreateLoad(asan_mapping_offset, true);
806 if (ClMappingScale) {
807 GlobalValue *asan_mapping_scale =
808 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
809 ConstantInt::get(IntptrTy, MappingScale()),
810 kAsanMappingScaleName);
811 // Read the global, otherwise it may be optimized away.
812 IRB.CreateLoad(asan_mapping_scale, true);
815 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
820 bool AddressSanitizer::doFinalization(Module &M) {
821 // We transform the globals at the very end so that the optimization analysis
822 // works on the original globals.
824 // FIXME: instead of doFinalization, run this as a true ModulePass.
825 AddressSanitizerCreateGlobalRedzonesPass Pass;
826 return Pass.runOnModule(M, TD);
832 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
833 // For each NSObject descendant having a +load method, this method is invoked
834 // by the ObjC runtime before any of the static constructors is called.
835 // Therefore we need to instrument such methods with a call to __asan_init
836 // at the beginning in order to initialize our runtime before any access to
837 // the shadow memory.
838 // We cannot just ignore these methods, because they may call other
839 // instrumented functions.
840 if (F.getName().find(" load]") != std::string::npos) {
841 IRBuilder<> IRB(F.begin()->begin());
842 IRB.CreateCall(AsanInitFunction);
848 bool AddressSanitizer::runOnFunction(Function &F) {
849 if (BL->isIn(F)) return false;
850 if (&F == AsanCtorFunction) return false;
851 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
853 // If needed, insert __asan_init before checking for AddressSafety attr.
854 maybeInsertAsanInitAtFunctionEntry(F);
856 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
859 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
862 // We want to instrument every address only once per basic block (unless there
863 // are calls between uses).
864 SmallSet<Value*, 16> TempsToInstrument;
865 SmallVector<Instruction*, 16> ToInstrument;
866 SmallVector<Instruction*, 8> NoReturnCalls;
869 // Fill the set of memory operations to instrument.
870 for (Function::iterator FI = F.begin(), FE = F.end();
872 TempsToInstrument.clear();
873 int NumInsnsPerBB = 0;
874 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
876 if (LooksLikeCodeInBug11395(BI)) return false;
877 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
878 if (ClOpt && ClOptSameTemp) {
879 if (!TempsToInstrument.insert(Addr))
880 continue; // We've seen this temp in the current BB.
882 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
885 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
887 TempsToInstrument.clear();
888 if (CI->doesNotReturn()) {
889 NoReturnCalls.push_back(CI);
894 ToInstrument.push_back(BI);
896 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
902 int NumInstrumented = 0;
903 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
904 Instruction *Inst = ToInstrument[i];
905 if (ClDebugMin < 0 || ClDebugMax < 0 ||
906 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
907 if (isInterestingMemoryAccess(Inst, &IsWrite))
910 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
915 bool ChangedStack = poisonStackInFunction(F);
917 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
918 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
919 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
920 Instruction *CI = NoReturnCalls[i];
922 IRB.CreateCall(AsanHandleNoReturnFunc);
924 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
926 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
929 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
930 if (ShadowRedzoneSize == 1) return PoisonByte;
931 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
932 if (ShadowRedzoneSize == 4)
933 return (PoisonByte << 24) + (PoisonByte << 16) +
934 (PoisonByte << 8) + (PoisonByte);
935 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
938 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
941 size_t ShadowGranularity,
943 for (size_t i = 0; i < RZSize;
944 i+= ShadowGranularity, Shadow++) {
945 if (i + ShadowGranularity <= Size) {
946 *Shadow = 0; // fully addressable
947 } else if (i >= Size) {
948 *Shadow = Magic; // unaddressable
950 *Shadow = Size - i; // first Size-i bytes are addressable
955 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
957 Value *ShadowBase, bool DoPoison) {
958 size_t ShadowRZSize = RedzoneSize() >> MappingScale();
959 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
960 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
961 Type *RZPtrTy = PointerType::get(RZTy, 0);
963 Value *PoisonLeft = ConstantInt::get(RZTy,
964 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
965 Value *PoisonMid = ConstantInt::get(RZTy,
966 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
967 Value *PoisonRight = ConstantInt::get(RZTy,
968 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
970 // poison the first red zone.
971 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
973 // poison all other red zones.
974 uint64_t Pos = RedzoneSize();
975 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
976 AllocaInst *AI = AllocaVec[i];
977 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
978 uint64_t AlignedSize = getAlignedAllocaSize(AI);
979 assert(AlignedSize - SizeInBytes < RedzoneSize());
984 assert(ShadowBase->getType() == IntptrTy);
985 if (SizeInBytes < AlignedSize) {
986 // Poison the partial redzone at right
988 ShadowBase, ConstantInt::get(IntptrTy,
989 (Pos >> MappingScale()) - ShadowRZSize));
990 size_t AddressableBytes = RedzoneSize() - (AlignedSize - SizeInBytes);
993 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
995 1ULL << MappingScale(),
996 kAsanStackPartialRedzoneMagic);
998 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
999 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1002 // Poison the full redzone at right.
1003 Ptr = IRB.CreateAdd(ShadowBase,
1004 ConstantInt::get(IntptrTy, Pos >> MappingScale()));
1005 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
1006 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1008 Pos += RedzoneSize();
1012 // Workaround for bug 11395: we don't want to instrument stack in functions
1013 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
1014 // FIXME: remove once the bug 11395 is fixed.
1015 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
1016 if (LongSize != 32) return false;
1017 CallInst *CI = dyn_cast<CallInst>(I);
1018 if (!CI || !CI->isInlineAsm()) return false;
1019 if (CI->getNumArgOperands() <= 5) return false;
1020 // We have inline assembly with quite a few arguments.
1024 // Find all static Alloca instructions and put
1025 // poisoned red zones around all of them.
1026 // Then unpoison everything back before the function returns.
1028 // Stack poisoning does not play well with exception handling.
1029 // When an exception is thrown, we essentially bypass the code
1030 // that unpoisones the stack. This is why the run-time library has
1031 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1032 // stack in the interceptor. This however does not work inside the
1033 // actual function which catches the exception. Most likely because the
1034 // compiler hoists the load of the shadow value somewhere too high.
1035 // This causes asan to report a non-existing bug on 453.povray.
1036 // It sounds like an LLVM bug.
1037 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1038 if (!ClStack) return false;
1039 SmallVector<AllocaInst*, 16> AllocaVec;
1040 SmallVector<Instruction*, 8> RetVec;
1041 uint64_t TotalSize = 0;
1043 // Filter out Alloca instructions we want (and can) handle.
1044 // Collect Ret instructions.
1045 for (Function::iterator FI = F.begin(), FE = F.end();
1047 BasicBlock &BB = *FI;
1048 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1050 if (isa<ReturnInst>(BI)) {
1051 RetVec.push_back(BI);
1055 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1057 if (AI->isArrayAllocation()) continue;
1058 if (!AI->isStaticAlloca()) continue;
1059 if (!AI->getAllocatedType()->isSized()) continue;
1060 if (AI->getAlignment() > RedzoneSize()) continue;
1061 AllocaVec.push_back(AI);
1062 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1063 TotalSize += AlignedSize;
1067 if (AllocaVec.empty()) return false;
1069 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize();
1071 bool DoStackMalloc = ClUseAfterReturn
1072 && LocalStackSize <= kMaxStackMallocSize;
1074 Instruction *InsBefore = AllocaVec[0];
1075 IRBuilder<> IRB(InsBefore);
1078 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1079 AllocaInst *MyAlloca =
1080 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1081 MyAlloca->setAlignment(RedzoneSize());
1082 assert(MyAlloca->isStaticAlloca());
1083 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1084 Value *LocalStackBase = OrigStackBase;
1086 if (DoStackMalloc) {
1087 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1088 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1091 // This string will be parsed by the run-time (DescribeStackAddress).
1092 SmallString<2048> StackDescriptionStorage;
1093 raw_svector_ostream StackDescription(StackDescriptionStorage);
1094 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1096 uint64_t Pos = RedzoneSize();
1097 // Replace Alloca instructions with base+offset.
1098 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1099 AllocaInst *AI = AllocaVec[i];
1100 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1101 StringRef Name = AI->getName();
1102 StackDescription << Pos << " " << SizeInBytes << " "
1103 << Name.size() << " " << Name << " ";
1104 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1105 assert((AlignedSize % RedzoneSize()) == 0);
1106 AI->replaceAllUsesWith(
1108 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1110 Pos += AlignedSize + RedzoneSize();
1112 assert(Pos == LocalStackSize);
1114 // Write the Magic value and the frame description constant to the redzone.
1115 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1116 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1118 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1119 ConstantInt::get(IntptrTy, LongSize/8));
1120 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1121 GlobalVariable *StackDescriptionGlobal =
1122 createPrivateGlobalForString(*F.getParent(), StackDescription.str());
1123 Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
1124 IRB.CreateStore(Description, BasePlus1);
1126 // Poison the stack redzones at the entry.
1127 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1128 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1130 // Unpoison the stack before all ret instructions.
1131 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1132 Instruction *Ret = RetVec[i];
1133 IRBuilder<> IRBRet(Ret);
1135 // Mark the current frame as retired.
1136 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1138 // Unpoison the stack.
1139 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1141 if (DoStackMalloc) {
1142 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1143 ConstantInt::get(IntptrTy, LocalStackSize),
1148 // We are done. Remove the old unused alloca instructions.
1149 for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
1150 AllocaVec[i]->eraseFromParent();