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 return "AddressSanitizerFunctionPass";
193 void instrumentMop(Instruction *I);
194 void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
195 Value *Addr, uint32_t TypeSize, bool IsWrite);
196 Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
197 Value *ShadowValue, uint32_t TypeSize);
198 Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
199 bool IsWrite, size_t AccessSizeIndex);
200 bool instrumentMemIntrinsic(MemIntrinsic *MI);
201 void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
203 Instruction *InsertBefore, bool IsWrite);
204 Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
205 bool runOnFunction(Function &F);
206 void createInitializerPoisonCalls(Module &M,
207 Value *FirstAddr, Value *LastAddr);
208 bool maybeInsertAsanInitAtFunctionEntry(Function &F);
209 bool poisonStackInFunction(Function &F);
210 virtual bool doInitialization(Module &M);
211 static char ID; // Pass identification, replacement for typeid
214 uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
215 Type *Ty = AI->getAllocatedType();
216 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
219 uint64_t getAlignedSize(uint64_t SizeInBytes) {
220 size_t RZ = RedzoneSize();
221 return ((SizeInBytes + RZ - 1) / RZ) * RZ;
223 uint64_t getAlignedAllocaSize(AllocaInst *AI) {
224 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
225 return getAlignedSize(SizeInBytes);
228 bool ShouldInstrumentGlobal(GlobalVariable *G);
229 void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
230 Value *ShadowBase, bool DoPoison);
231 bool LooksLikeCodeInBug11395(Instruction *I);
232 void FindDynamicInitializers(Module &M);
236 uint64_t MappingOffset;
240 Function *AsanCtorFunction;
241 Function *AsanInitFunction;
242 Function *AsanStackMallocFunc, *AsanStackFreeFunc;
243 Function *AsanHandleNoReturnFunc;
244 OwningPtr<BlackList> BL;
245 // This array is indexed by AccessIsWrite and log2(AccessSize).
246 Function *AsanErrorCallback[2][kNumberOfAccessSizes];
248 SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
251 class AddressSanitizerModule : public ModulePass {
253 bool runOnModule(Module &M);
254 static char ID; // Pass identification, replacement for typeid
255 AddressSanitizerModule() : ModulePass(ID) { }
256 virtual const char *getPassName() const {
257 return "AddressSanitizerModule";
260 bool ShouldInstrumentGlobal(GlobalVariable *G);
261 void createInitializerPoisonCalls(Module &M, Value *FirstAddr,
264 OwningPtr<BlackList> BL;
265 SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
273 char AddressSanitizer::ID = 0;
274 INITIALIZE_PASS(AddressSanitizer, "asan",
275 "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
277 AddressSanitizer::AddressSanitizer() : FunctionPass(ID) { }
278 FunctionPass *llvm::createAddressSanitizerFunctionPass() {
279 return new AddressSanitizer();
282 char AddressSanitizerModule::ID = 0;
283 INITIALIZE_PASS(AddressSanitizerModule, "asan-module",
284 "AddressSanitizer: detects use-after-free and out-of-bounds bugs."
285 "ModulePass", false, false)
286 ModulePass *llvm::createAddressSanitizerModulePass() {
287 return new AddressSanitizerModule();
290 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
291 size_t Res = CountTrailingZeros_32(TypeSize / 8);
292 assert(Res < kNumberOfAccessSizes);
296 // Create a constant for Str so that we can pass it to the run-time lib.
297 static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
298 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
299 return new GlobalVariable(M, StrConst->getType(), true,
300 GlobalValue::PrivateLinkage, StrConst,
304 static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
305 return G->getName().find(kAsanGenPrefix) == 0;
308 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
310 Shadow = IRB.CreateLShr(Shadow, MappingScale());
311 if (MappingOffset == 0)
313 // (Shadow >> scale) | offset
314 return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
318 void AddressSanitizer::instrumentMemIntrinsicParam(
319 Instruction *OrigIns,
320 Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
321 // Check the first byte.
323 IRBuilder<> IRB(InsertBefore);
324 instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
326 // Check the last byte.
328 IRBuilder<> IRB(InsertBefore);
329 Value *SizeMinusOne = IRB.CreateSub(
330 Size, ConstantInt::get(Size->getType(), 1));
331 SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
332 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
333 Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
334 instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
338 // Instrument memset/memmove/memcpy
339 bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
340 Value *Dst = MI->getDest();
341 MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
342 Value *Src = MemTran ? MemTran->getSource() : 0;
343 Value *Length = MI->getLength();
345 Constant *ConstLength = dyn_cast<Constant>(Length);
346 Instruction *InsertBefore = MI;
348 if (ConstLength->isNullValue()) return false;
350 // The size is not a constant so it could be zero -- check at run-time.
351 IRBuilder<> IRB(InsertBefore);
353 Value *Cmp = IRB.CreateICmpNE(Length,
354 Constant::getNullValue(Length->getType()));
355 InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
358 instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
360 instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
364 // If I is an interesting memory access, return the PointerOperand
365 // and set IsWrite. Otherwise return NULL.
366 static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
367 if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
368 if (!ClInstrumentReads) return NULL;
370 return LI->getPointerOperand();
372 if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
373 if (!ClInstrumentWrites) return NULL;
375 return SI->getPointerOperand();
377 if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
378 if (!ClInstrumentAtomics) return NULL;
380 return RMW->getPointerOperand();
382 if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
383 if (!ClInstrumentAtomics) return NULL;
385 return XCHG->getPointerOperand();
390 void AddressSanitizer::instrumentMop(Instruction *I) {
391 bool IsWrite = false;
392 Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
394 if (ClOpt && ClOptGlobals) {
395 if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
396 // If initialization order checking is disabled, a simple access to a
397 // dynamically initialized global is always valid.
400 // If a global variable does not have dynamic initialization we don't
401 // have to instrument it. However, if a global does not have initailizer
402 // at all, we assume it has dynamic initializer (in other TU).
403 if (G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G))
408 Type *OrigPtrTy = Addr->getType();
409 Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
411 assert(OrigTy->isSized());
412 uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
414 if (TypeSize != 8 && TypeSize != 16 &&
415 TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
416 // Ignore all unusual sizes.
421 instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
424 // Validate the result of Module::getOrInsertFunction called for an interface
425 // function of AddressSanitizer. If the instrumented module defines a function
426 // with the same name, their prototypes must match, otherwise
427 // getOrInsertFunction returns a bitcast.
428 static Function *checkInterfaceFunction(Constant *FuncOrBitcast) {
429 if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
430 FuncOrBitcast->dump();
431 report_fatal_error("trying to redefine an AddressSanitizer "
432 "interface function");
435 Instruction *AddressSanitizer::generateCrashCode(
436 Instruction *InsertBefore, Value *Addr,
437 bool IsWrite, size_t AccessSizeIndex) {
438 IRBuilder<> IRB(InsertBefore);
439 CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
441 // We don't do Call->setDoesNotReturn() because the BB already has
442 // UnreachableInst at the end.
443 // This EmptyAsm is required to avoid callback merge.
444 IRB.CreateCall(EmptyAsm);
448 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
451 size_t Granularity = 1 << MappingScale();
452 // Addr & (Granularity - 1)
453 Value *LastAccessedByte = IRB.CreateAnd(
454 AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
455 // (Addr & (Granularity - 1)) + size - 1
456 if (TypeSize / 8 > 1)
457 LastAccessedByte = IRB.CreateAdd(
458 LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
459 // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
460 LastAccessedByte = IRB.CreateIntCast(
461 LastAccessedByte, ShadowValue->getType(), false);
462 // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
463 return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
466 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
467 IRBuilder<> &IRB, Value *Addr,
468 uint32_t TypeSize, bool IsWrite) {
469 Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
471 Type *ShadowTy = IntegerType::get(
472 *C, std::max(8U, TypeSize >> MappingScale()));
473 Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
474 Value *ShadowPtr = memToShadow(AddrLong, IRB);
475 Value *CmpVal = Constant::getNullValue(ShadowTy);
476 Value *ShadowValue = IRB.CreateLoad(
477 IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
479 Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
480 size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
481 size_t Granularity = 1 << MappingScale();
482 TerminatorInst *CrashTerm = 0;
484 if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
485 TerminatorInst *CheckTerm =
486 SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
487 assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
488 BasicBlock *NextBB = CheckTerm->getSuccessor(0);
489 IRB.SetInsertPoint(CheckTerm);
490 Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
491 BasicBlock *CrashBlock =
492 BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
493 CrashTerm = new UnreachableInst(*C, CrashBlock);
494 BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
495 ReplaceInstWithInst(CheckTerm, NewTerm);
497 CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
501 generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
502 Crash->setDebugLoc(OrigIns->getDebugLoc());
505 void AddressSanitizerModule::createInitializerPoisonCalls(
506 Module &M, Value *FirstAddr, Value *LastAddr) {
507 // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
508 Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
509 // If that function is not present, this TU contains no globals, or they have
510 // all been optimized away
514 // Set up the arguments to our poison/unpoison functions.
515 IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
517 // Declare our poisoning and unpoisoning functions.
518 Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
519 kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
520 AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
521 Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
522 kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
523 AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
525 // Add a call to poison all external globals before the given function starts.
526 IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
528 // Add calls to unpoison all globals before each return instruction.
529 for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
531 if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
532 CallInst::Create(AsanUnpoisonGlobals, "", RI);
537 bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
538 Type *Ty = cast<PointerType>(G->getType())->getElementType();
539 DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
541 if (BL->isIn(*G)) return false;
542 if (!Ty->isSized()) return false;
543 if (!G->hasInitializer()) return false;
544 if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
545 // Touch only those globals that will not be defined in other modules.
546 // Don't handle ODR type linkages since other modules may be built w/o asan.
547 if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
548 G->getLinkage() != GlobalVariable::PrivateLinkage &&
549 G->getLinkage() != GlobalVariable::InternalLinkage)
551 // Two problems with thread-locals:
552 // - The address of the main thread's copy can't be computed at link-time.
553 // - Need to poison all copies, not just the main thread's one.
554 if (G->isThreadLocal())
556 // For now, just ignore this Alloca if the alignment is large.
557 if (G->getAlignment() > RedzoneSize()) return false;
559 // Ignore all the globals with the names starting with "\01L_OBJC_".
560 // Many of those are put into the .cstring section. The linker compresses
561 // that section by removing the spare \0s after the string terminator, so
562 // our redzones get broken.
563 if ((G->getName().find("\01L_OBJC_") == 0) ||
564 (G->getName().find("\01l_OBJC_") == 0)) {
565 DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
569 if (G->hasSection()) {
570 StringRef Section(G->getSection());
571 // Ignore the globals from the __OBJC section. The ObjC runtime assumes
572 // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
574 if ((Section.find("__OBJC,") == 0) ||
575 (Section.find("__DATA, __objc_") == 0)) {
576 DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
579 // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
580 // Constant CFString instances are compiled in the following way:
581 // -- the string buffer is emitted into
582 // __TEXT,__cstring,cstring_literals
583 // -- the constant NSConstantString structure referencing that buffer
584 // is placed into __DATA,__cfstring
585 // Therefore there's no point in placing redzones into __DATA,__cfstring.
586 // Moreover, it causes the linker to crash on OS X 10.7
587 if (Section.find("__DATA,__cfstring") == 0) {
588 DEBUG(dbgs() << "Ignoring CFString: " << *G);
596 // This function replaces all global variables with new variables that have
597 // trailing redzones. It also creates a function that poisons
598 // redzones and inserts this function into llvm.global_ctors.
599 bool AddressSanitizerModule::runOnModule(Module &M) {
600 if (!ClGlobals) return false;
601 TD = getAnalysisIfAvailable<DataLayout>();
604 BL.reset(new BlackList(ClBlackListFile));
605 DynamicallyInitializedGlobals.Init(M);
606 C = &(M.getContext());
607 IntptrTy = Type::getIntNTy(*C, TD->getPointerSizeInBits());
609 SmallVector<GlobalVariable *, 16> GlobalsToChange;
611 for (Module::GlobalListType::iterator G = M.global_begin(),
612 E = M.global_end(); G != E; ++G) {
613 if (ShouldInstrumentGlobal(G))
614 GlobalsToChange.push_back(G);
617 size_t n = GlobalsToChange.size();
618 if (n == 0) return false;
620 // A global is described by a structure
623 // size_t size_with_redzone;
625 // size_t has_dynamic_init;
626 // We initialize an array of such structures and pass it to a run-time call.
627 StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
630 SmallVector<Constant *, 16> Initializers(n), DynamicInit;
633 Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
635 IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
637 // The addresses of the first and last dynamically initialized globals in
638 // this TU. Used in initialization order checking.
639 Value *FirstDynamic = 0, *LastDynamic = 0;
641 for (size_t i = 0; i < n; i++) {
642 GlobalVariable *G = GlobalsToChange[i];
643 PointerType *PtrTy = cast<PointerType>(G->getType());
644 Type *Ty = PtrTy->getElementType();
645 uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
646 size_t RZ = RedzoneSize();
647 uint64_t RightRedzoneSize = RZ + (RZ - (SizeInBytes % RZ));
648 Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
649 // Determine whether this global should be poisoned in initialization.
650 bool GlobalHasDynamicInitializer =
651 DynamicallyInitializedGlobals.Contains(G);
652 // Don't check initialization order if this global is blacklisted.
653 GlobalHasDynamicInitializer &= !BL->isInInit(*G);
655 StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
656 Constant *NewInitializer = ConstantStruct::get(
657 NewTy, G->getInitializer(),
658 Constant::getNullValue(RightRedZoneTy), NULL);
660 SmallString<2048> DescriptionOfGlobal = G->getName();
661 DescriptionOfGlobal += " (";
662 DescriptionOfGlobal += M.getModuleIdentifier();
663 DescriptionOfGlobal += ")";
664 GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
666 // Create a new global variable with enough space for a redzone.
667 GlobalVariable *NewGlobal = new GlobalVariable(
668 M, NewTy, G->isConstant(), G->getLinkage(),
669 NewInitializer, "", G, G->getThreadLocalMode());
670 NewGlobal->copyAttributesFrom(G);
671 NewGlobal->setAlignment(RZ);
674 Indices2[0] = IRB.getInt32(0);
675 Indices2[1] = IRB.getInt32(0);
677 G->replaceAllUsesWith(
678 ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
679 NewGlobal->takeName(G);
680 G->eraseFromParent();
682 Initializers[i] = ConstantStruct::get(
684 ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
685 ConstantInt::get(IntptrTy, SizeInBytes),
686 ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
687 ConstantExpr::getPointerCast(Name, IntptrTy),
688 ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
691 // Populate the first and last globals declared in this TU.
692 if (ClInitializers && GlobalHasDynamicInitializer) {
693 LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
694 if (FirstDynamic == 0)
695 FirstDynamic = LastDynamic;
698 DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
701 ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
702 GlobalVariable *AllGlobals = new GlobalVariable(
703 M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
704 ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
706 // Create calls for poisoning before initializers run and unpoisoning after.
707 if (ClInitializers && FirstDynamic && LastDynamic)
708 createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
710 Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
711 kAsanRegisterGlobalsName, IRB.getVoidTy(),
712 IntptrTy, IntptrTy, NULL));
713 AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
715 IRB.CreateCall2(AsanRegisterGlobals,
716 IRB.CreatePointerCast(AllGlobals, IntptrTy),
717 ConstantInt::get(IntptrTy, n));
719 // We also need to unregister globals at the end, e.g. when a shared library
721 Function *AsanDtorFunction = Function::Create(
722 FunctionType::get(Type::getVoidTy(*C), false),
723 GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
724 BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
725 IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
726 Function *AsanUnregisterGlobals =
727 checkInterfaceFunction(M.getOrInsertFunction(
728 kAsanUnregisterGlobalsName,
729 IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
730 AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
732 IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
733 IRB.CreatePointerCast(AllGlobals, IntptrTy),
734 ConstantInt::get(IntptrTy, n));
735 appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
742 bool AddressSanitizer::doInitialization(Module &M) {
743 // Initialize the private fields. No one has accessed them before.
744 TD = getAnalysisIfAvailable<DataLayout>();
748 BL.reset(new BlackList(ClBlackListFile));
749 DynamicallyInitializedGlobals.Init(M);
751 C = &(M.getContext());
752 LongSize = TD->getPointerSizeInBits();
753 IntptrTy = Type::getIntNTy(*C, LongSize);
754 IntptrPtrTy = PointerType::get(IntptrTy, 0);
756 AsanCtorFunction = Function::Create(
757 FunctionType::get(Type::getVoidTy(*C), false),
758 GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
759 BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
760 // call __asan_init in the module ctor.
761 IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
762 AsanInitFunction = checkInterfaceFunction(
763 M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
764 AsanInitFunction->setLinkage(Function::ExternalLinkage);
765 IRB.CreateCall(AsanInitFunction);
767 // Create __asan_report* callbacks.
768 for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
769 for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
771 // IsWrite and TypeSize are encoded in the function name.
772 std::string FunctionName = std::string(kAsanReportErrorTemplate) +
773 (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
774 // If we are merging crash callbacks, they have two parameters.
775 AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
776 checkInterfaceFunction(M.getOrInsertFunction(
777 FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
781 AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
782 kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
783 AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
784 kAsanStackFreeName, IRB.getVoidTy(),
785 IntptrTy, IntptrTy, IntptrTy, NULL));
786 AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
787 kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
789 // We insert an empty inline asm after __asan_report* to avoid callback merge.
790 EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
791 StringRef(""), StringRef(""),
792 /*hasSideEffects=*/true);
794 llvm::Triple targetTriple(M.getTargetTriple());
795 bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
797 MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
798 (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
799 if (ClMappingOffsetLog >= 0) {
800 if (ClMappingOffsetLog == 0) {
804 MappingOffset = 1ULL << ClMappingOffsetLog;
809 if (ClMappingOffsetLog >= 0) {
810 // Tell the run-time the current values of mapping offset and scale.
811 GlobalValue *asan_mapping_offset =
812 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
813 ConstantInt::get(IntptrTy, MappingOffset),
814 kAsanMappingOffsetName);
815 // Read the global, otherwise it may be optimized away.
816 IRB.CreateLoad(asan_mapping_offset, true);
818 if (ClMappingScale) {
819 GlobalValue *asan_mapping_scale =
820 new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
821 ConstantInt::get(IntptrTy, MappingScale()),
822 kAsanMappingScaleName);
823 // Read the global, otherwise it may be optimized away.
824 IRB.CreateLoad(asan_mapping_scale, true);
827 appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
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 // Check both the call and the callee for doesNotReturn().
849 static bool isNoReturnCall(CallInst *CI) {
850 if (CI->doesNotReturn()) return true;
851 Function *F = CI->getCalledFunction();
852 if (F && F->doesNotReturn()) return true;
856 bool AddressSanitizer::runOnFunction(Function &F) {
857 if (BL->isIn(F)) return false;
858 if (&F == AsanCtorFunction) return false;
859 DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
861 // If needed, insert __asan_init before checking for AddressSafety attr.
862 maybeInsertAsanInitAtFunctionEntry(F);
864 if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
867 if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
870 // We want to instrument every address only once per basic block (unless there
871 // are calls between uses).
872 SmallSet<Value*, 16> TempsToInstrument;
873 SmallVector<Instruction*, 16> ToInstrument;
874 SmallVector<Instruction*, 8> NoReturnCalls;
877 // Fill the set of memory operations to instrument.
878 for (Function::iterator FI = F.begin(), FE = F.end();
880 TempsToInstrument.clear();
881 int NumInsnsPerBB = 0;
882 for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
884 if (LooksLikeCodeInBug11395(BI)) return false;
885 if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
886 if (ClOpt && ClOptSameTemp) {
887 if (!TempsToInstrument.insert(Addr))
888 continue; // We've seen this temp in the current BB.
890 } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
893 if (CallInst *CI = dyn_cast<CallInst>(BI)) {
895 TempsToInstrument.clear();
896 if (isNoReturnCall(CI)) {
897 NoReturnCalls.push_back(CI);
902 ToInstrument.push_back(BI);
904 if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
910 int NumInstrumented = 0;
911 for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
912 Instruction *Inst = ToInstrument[i];
913 if (ClDebugMin < 0 || ClDebugMax < 0 ||
914 (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
915 if (isInterestingMemoryAccess(Inst, &IsWrite))
918 instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
923 bool ChangedStack = poisonStackInFunction(F);
925 // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
926 // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
927 for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
928 Instruction *CI = NoReturnCalls[i];
930 IRB.CreateCall(AsanHandleNoReturnFunc);
932 DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
934 return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
937 static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
938 if (ShadowRedzoneSize == 1) return PoisonByte;
939 if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
940 if (ShadowRedzoneSize == 4)
941 return (PoisonByte << 24) + (PoisonByte << 16) +
942 (PoisonByte << 8) + (PoisonByte);
943 llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
946 static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
949 size_t ShadowGranularity,
951 for (size_t i = 0; i < RZSize;
952 i+= ShadowGranularity, Shadow++) {
953 if (i + ShadowGranularity <= Size) {
954 *Shadow = 0; // fully addressable
955 } else if (i >= Size) {
956 *Shadow = Magic; // unaddressable
958 *Shadow = Size - i; // first Size-i bytes are addressable
963 void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
965 Value *ShadowBase, bool DoPoison) {
966 size_t ShadowRZSize = RedzoneSize() >> MappingScale();
967 assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
968 Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
969 Type *RZPtrTy = PointerType::get(RZTy, 0);
971 Value *PoisonLeft = ConstantInt::get(RZTy,
972 ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
973 Value *PoisonMid = ConstantInt::get(RZTy,
974 ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
975 Value *PoisonRight = ConstantInt::get(RZTy,
976 ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
978 // poison the first red zone.
979 IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
981 // poison all other red zones.
982 uint64_t Pos = RedzoneSize();
983 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
984 AllocaInst *AI = AllocaVec[i];
985 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
986 uint64_t AlignedSize = getAlignedAllocaSize(AI);
987 assert(AlignedSize - SizeInBytes < RedzoneSize());
992 assert(ShadowBase->getType() == IntptrTy);
993 if (SizeInBytes < AlignedSize) {
994 // Poison the partial redzone at right
996 ShadowBase, ConstantInt::get(IntptrTy,
997 (Pos >> MappingScale()) - ShadowRZSize));
998 size_t AddressableBytes = RedzoneSize() - (AlignedSize - SizeInBytes);
1001 PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
1003 1ULL << MappingScale(),
1004 kAsanStackPartialRedzoneMagic);
1006 Value *PartialPoison = ConstantInt::get(RZTy, Poison);
1007 IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1010 // Poison the full redzone at right.
1011 Ptr = IRB.CreateAdd(ShadowBase,
1012 ConstantInt::get(IntptrTy, Pos >> MappingScale()));
1013 Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
1014 IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
1016 Pos += RedzoneSize();
1020 // Workaround for bug 11395: we don't want to instrument stack in functions
1021 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
1022 // FIXME: remove once the bug 11395 is fixed.
1023 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
1024 if (LongSize != 32) return false;
1025 CallInst *CI = dyn_cast<CallInst>(I);
1026 if (!CI || !CI->isInlineAsm()) return false;
1027 if (CI->getNumArgOperands() <= 5) return false;
1028 // We have inline assembly with quite a few arguments.
1032 // Find all static Alloca instructions and put
1033 // poisoned red zones around all of them.
1034 // Then unpoison everything back before the function returns.
1036 // Stack poisoning does not play well with exception handling.
1037 // When an exception is thrown, we essentially bypass the code
1038 // that unpoisones the stack. This is why the run-time library has
1039 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
1040 // stack in the interceptor. This however does not work inside the
1041 // actual function which catches the exception. Most likely because the
1042 // compiler hoists the load of the shadow value somewhere too high.
1043 // This causes asan to report a non-existing bug on 453.povray.
1044 // It sounds like an LLVM bug.
1045 bool AddressSanitizer::poisonStackInFunction(Function &F) {
1046 if (!ClStack) return false;
1047 SmallVector<AllocaInst*, 16> AllocaVec;
1048 SmallVector<Instruction*, 8> RetVec;
1049 uint64_t TotalSize = 0;
1051 // Filter out Alloca instructions we want (and can) handle.
1052 // Collect Ret instructions.
1053 for (Function::iterator FI = F.begin(), FE = F.end();
1055 BasicBlock &BB = *FI;
1056 for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
1058 if (isa<ReturnInst>(BI)) {
1059 RetVec.push_back(BI);
1063 AllocaInst *AI = dyn_cast<AllocaInst>(BI);
1065 if (AI->isArrayAllocation()) continue;
1066 if (!AI->isStaticAlloca()) continue;
1067 if (!AI->getAllocatedType()->isSized()) continue;
1068 if (AI->getAlignment() > RedzoneSize()) continue;
1069 AllocaVec.push_back(AI);
1070 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1071 TotalSize += AlignedSize;
1075 if (AllocaVec.empty()) return false;
1077 uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize();
1079 bool DoStackMalloc = ClUseAfterReturn
1080 && LocalStackSize <= kMaxStackMallocSize;
1082 Instruction *InsBefore = AllocaVec[0];
1083 IRBuilder<> IRB(InsBefore);
1086 Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
1087 AllocaInst *MyAlloca =
1088 new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
1089 MyAlloca->setAlignment(RedzoneSize());
1090 assert(MyAlloca->isStaticAlloca());
1091 Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
1092 Value *LocalStackBase = OrigStackBase;
1094 if (DoStackMalloc) {
1095 LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
1096 ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
1099 // This string will be parsed by the run-time (DescribeStackAddress).
1100 SmallString<2048> StackDescriptionStorage;
1101 raw_svector_ostream StackDescription(StackDescriptionStorage);
1102 StackDescription << F.getName() << " " << AllocaVec.size() << " ";
1104 uint64_t Pos = RedzoneSize();
1105 // Replace Alloca instructions with base+offset.
1106 for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
1107 AllocaInst *AI = AllocaVec[i];
1108 uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
1109 StringRef Name = AI->getName();
1110 StackDescription << Pos << " " << SizeInBytes << " "
1111 << Name.size() << " " << Name << " ";
1112 uint64_t AlignedSize = getAlignedAllocaSize(AI);
1113 assert((AlignedSize % RedzoneSize()) == 0);
1114 AI->replaceAllUsesWith(
1116 IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
1118 Pos += AlignedSize + RedzoneSize();
1120 assert(Pos == LocalStackSize);
1122 // Write the Magic value and the frame description constant to the redzone.
1123 Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
1124 IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
1126 Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
1127 ConstantInt::get(IntptrTy, LongSize/8));
1128 BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
1129 GlobalVariable *StackDescriptionGlobal =
1130 createPrivateGlobalForString(*F.getParent(), StackDescription.str());
1131 Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
1132 IRB.CreateStore(Description, BasePlus1);
1134 // Poison the stack redzones at the entry.
1135 Value *ShadowBase = memToShadow(LocalStackBase, IRB);
1136 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
1138 // Unpoison the stack before all ret instructions.
1139 for (size_t i = 0, n = RetVec.size(); i < n; i++) {
1140 Instruction *Ret = RetVec[i];
1141 IRBuilder<> IRBRet(Ret);
1143 // Mark the current frame as retired.
1144 IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
1146 // Unpoison the stack.
1147 PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
1149 if (DoStackMalloc) {
1150 IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
1151 ConstantInt::get(IntptrTy, LocalStackSize),
1156 // We are done. Remove the old unused alloca instructions.
1157 for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
1158 AllocaVec[i]->eraseFromParent();