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+//===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+// Details of the algorithm:
+// http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "asan"
+
+#include "BlackList.h"
+#include "llvm/Function.h"
+#include "llvm/IRBuilder.h"
+#include "llvm/InlineAsm.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Module.h"
+#include "llvm/Type.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/system_error.h"
+#include "llvm/DataLayout.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
+
+#include <string>
+#include <algorithm>
+
+using namespace llvm;
+
+static const uint64_t kDefaultShadowScale = 3;
+static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
+static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
+static const uint64_t kDefaultShadowOffsetAndroid = 0;
+
+static const size_t kMaxStackMallocSize = 1 << 16; // 64K
+static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
+static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
+
+static const char *kAsanModuleCtorName = "asan.module_ctor";
+static const char *kAsanModuleDtorName = "asan.module_dtor";
+static const int kAsanCtorAndCtorPriority = 1;
+static const char *kAsanReportErrorTemplate = "__asan_report_";
+static const char *kAsanRegisterGlobalsName = "__asan_register_globals";
+static const char *kAsanUnregisterGlobalsName = "__asan_unregister_globals";
+static const char *kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
+static const char *kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
+static const char *kAsanInitName = "__asan_init";
+static const char *kAsanHandleNoReturnName = "__asan_handle_no_return";
+static const char *kAsanMappingOffsetName = "__asan_mapping_offset";
+static const char *kAsanMappingScaleName = "__asan_mapping_scale";
+static const char *kAsanStackMallocName = "__asan_stack_malloc";
+static const char *kAsanStackFreeName = "__asan_stack_free";
+
+static const int kAsanStackLeftRedzoneMagic = 0xf1;
+static const int kAsanStackMidRedzoneMagic = 0xf2;
+static const int kAsanStackRightRedzoneMagic = 0xf3;
+static const int kAsanStackPartialRedzoneMagic = 0xf4;
+
+// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
+static const size_t kNumberOfAccessSizes = 5;
+
+// Command-line flags.
+
+// This flag may need to be replaced with -f[no-]asan-reads.
+static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
+ cl::desc("instrument read instructions"), cl::Hidden, cl::init(true));
+static cl::opt<bool> ClInstrumentWrites("asan-instrument-writes",
+ cl::desc("instrument write instructions"), cl::Hidden, cl::init(true));
+static cl::opt<bool> ClInstrumentAtomics("asan-instrument-atomics",
+ cl::desc("instrument atomic instructions (rmw, cmpxchg)"),
+ cl::Hidden, cl::init(true));
+static cl::opt<bool> ClAlwaysSlowPath("asan-always-slow-path",
+ cl::desc("use instrumentation with slow path for all accesses"),
+ cl::Hidden, cl::init(false));
+// This flag limits the number of instructions to be instrumented
+// in any given BB. Normally, this should be set to unlimited (INT_MAX),
+// but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
+// set it to 10000.
+static cl::opt<int> ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb",
+ cl::init(10000),
+ cl::desc("maximal number of instructions to instrument in any given BB"),
+ cl::Hidden);
+// This flag may need to be replaced with -f[no]asan-stack.
+static cl::opt<bool> ClStack("asan-stack",
+ cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
+// This flag may need to be replaced with -f[no]asan-use-after-return.
+static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
+ cl::desc("Check return-after-free"), cl::Hidden, cl::init(false));
+// This flag may need to be replaced with -f[no]asan-globals.
+static cl::opt<bool> ClGlobals("asan-globals",
+ cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
+static cl::opt<bool> ClInitializers("asan-initialization-order",
+ cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false));
+static cl::opt<bool> ClMemIntrin("asan-memintrin",
+ cl::desc("Handle memset/memcpy/memmove"), cl::Hidden, cl::init(true));
+// This flag may need to be replaced with -fasan-blacklist.
+static cl::opt<std::string> ClBlackListFile("asan-blacklist",
+ cl::desc("File containing the list of functions to ignore "
+ "during instrumentation"), cl::Hidden);
+
+// These flags allow to change the shadow mapping.
+// The shadow mapping looks like
+// Shadow = (Mem >> scale) + (1 << offset_log)
+static cl::opt<int> ClMappingScale("asan-mapping-scale",
+ cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0));
+static cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log",
+ cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1));
+
+// Optimization flags. Not user visible, used mostly for testing
+// and benchmarking the tool.
+static cl::opt<bool> ClOpt("asan-opt",
+ cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true));
+static cl::opt<bool> ClOptSameTemp("asan-opt-same-temp",
+ cl::desc("Instrument the same temp just once"), cl::Hidden,
+ cl::init(true));
+static cl::opt<bool> ClOptGlobals("asan-opt-globals",
+ cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true));
+
+// Debug flags.
+static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
+ cl::init(0));
+static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
+ cl::Hidden, cl::init(0));
+static cl::opt<std::string> ClDebugFunc("asan-debug-func",
+ cl::Hidden, cl::desc("Debug func"));
+static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
+ cl::Hidden, cl::init(-1));
+static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
+ cl::Hidden, cl::init(-1));
+
+namespace {
+/// AddressSanitizer: instrument the code in module to find memory bugs.
+struct AddressSanitizer : public FunctionPass {
+ AddressSanitizer();
+ virtual const char *getPassName() const;
+ void instrumentMop(Instruction *I);
+ void instrumentAddress(Instruction *OrigIns, IRBuilder<> &IRB,
+ Value *Addr, uint32_t TypeSize, bool IsWrite);
+ Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
+ Value *ShadowValue, uint32_t TypeSize);
+ Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
+ bool IsWrite, size_t AccessSizeIndex);
+ bool instrumentMemIntrinsic(MemIntrinsic *MI);
+ void instrumentMemIntrinsicParam(Instruction *OrigIns, Value *Addr,
+ Value *Size,
+ Instruction *InsertBefore, bool IsWrite);
+ Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
+ bool runOnFunction(Function &F);
+ void createInitializerPoisonCalls(Module &M,
+ Value *FirstAddr, Value *LastAddr);
+ bool maybeInsertAsanInitAtFunctionEntry(Function &F);
+ bool poisonStackInFunction(Function &F);
+ virtual bool doInitialization(Module &M);
+ virtual bool doFinalization(Module &M);
+ bool insertGlobalRedzones(Module &M);
+ static char ID; // Pass identification, replacement for typeid
+
+ private:
+ uint64_t getAllocaSizeInBytes(AllocaInst *AI) {
+ Type *Ty = AI->getAllocatedType();
+ uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
+ return SizeInBytes;
+ }
+ uint64_t getAlignedSize(uint64_t SizeInBytes) {
+ return ((SizeInBytes + RedzoneSize - 1)
+ / RedzoneSize) * RedzoneSize;
+ }
+ uint64_t getAlignedAllocaSize(AllocaInst *AI) {
+ uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
+ return getAlignedSize(SizeInBytes);
+ }
+
+ Function *checkInterfaceFunction(Constant *FuncOrBitcast);
+ bool ShouldInstrumentGlobal(GlobalVariable *G);
+ void PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec, IRBuilder<> IRB,
+ Value *ShadowBase, bool DoPoison);
+ bool LooksLikeCodeInBug11395(Instruction *I);
+ void FindDynamicInitializers(Module &M);
+ bool HasDynamicInitializer(GlobalVariable *G);
+
+ LLVMContext *C;
+ DataLayout *TD;
+ uint64_t MappingOffset;
+ int MappingScale;
+ size_t RedzoneSize;
+ int LongSize;
+ Type *IntptrTy;
+ Type *IntptrPtrTy;
+ Function *AsanCtorFunction;
+ Function *AsanInitFunction;
+ Function *AsanStackMallocFunc, *AsanStackFreeFunc;
+ Function *AsanHandleNoReturnFunc;
+ Instruction *CtorInsertBefore;
+ OwningPtr<BlackList> BL;
+ // This array is indexed by AccessIsWrite and log2(AccessSize).
+ Function *AsanErrorCallback[2][kNumberOfAccessSizes];
+ InlineAsm *EmptyAsm;
+ SmallSet<GlobalValue*, 32> DynamicallyInitializedGlobals;
+ SmallSet<GlobalValue*, 32> GlobalsCreatedByAsan;
+};
+
+} // namespace
+
+char AddressSanitizer::ID = 0;
+INITIALIZE_PASS(AddressSanitizer, "asan",
+ "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
+ false, false)
+AddressSanitizer::AddressSanitizer() : FunctionPass(ID) { }
+FunctionPass *llvm::createAddressSanitizerPass() {
+ return new AddressSanitizer();
+}
+
+const char *AddressSanitizer::getPassName() const {
+ return "AddressSanitizer";
+}
+
+static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
+ size_t Res = CountTrailingZeros_32(TypeSize / 8);
+ assert(Res < kNumberOfAccessSizes);
+ return Res;
+}
+
+// Create a constant for Str so that we can pass it to the run-time lib.
+static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
+ Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
+ return new GlobalVariable(M, StrConst->getType(), true,
+ GlobalValue::PrivateLinkage, StrConst, "");
+}
+
+Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
+ // Shadow >> scale
+ Shadow = IRB.CreateLShr(Shadow, MappingScale);
+ if (MappingOffset == 0)
+ return Shadow;
+ // (Shadow >> scale) | offset
+ return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy,
+ MappingOffset));
+}
+
+void AddressSanitizer::instrumentMemIntrinsicParam(
+ Instruction *OrigIns,
+ Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
+ // Check the first byte.
+ {
+ IRBuilder<> IRB(InsertBefore);
+ instrumentAddress(OrigIns, IRB, Addr, 8, IsWrite);
+ }
+ // Check the last byte.
+ {
+ IRBuilder<> IRB(InsertBefore);
+ Value *SizeMinusOne = IRB.CreateSub(
+ Size, ConstantInt::get(Size->getType(), 1));
+ SizeMinusOne = IRB.CreateIntCast(SizeMinusOne, IntptrTy, false);
+ Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
+ Value *AddrPlusSizeMinisOne = IRB.CreateAdd(AddrLong, SizeMinusOne);
+ instrumentAddress(OrigIns, IRB, AddrPlusSizeMinisOne, 8, IsWrite);
+ }
+}
+
+// Instrument memset/memmove/memcpy
+bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
+ Value *Dst = MI->getDest();
+ MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
+ Value *Src = MemTran ? MemTran->getSource() : 0;
+ Value *Length = MI->getLength();
+
+ Constant *ConstLength = dyn_cast<Constant>(Length);
+ Instruction *InsertBefore = MI;
+ if (ConstLength) {
+ if (ConstLength->isNullValue()) return false;
+ } else {
+ // The size is not a constant so it could be zero -- check at run-time.
+ IRBuilder<> IRB(InsertBefore);
+
+ Value *Cmp = IRB.CreateICmpNE(Length,
+ Constant::getNullValue(Length->getType()));
+ InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
+ }
+
+ instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
+ if (Src)
+ instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
+ return true;
+}
+
+// If I is an interesting memory access, return the PointerOperand
+// and set IsWrite. Otherwise return NULL.
+static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
+ if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+ if (!ClInstrumentReads) return NULL;
+ *IsWrite = false;
+ return LI->getPointerOperand();
+ }
+ if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
+ if (!ClInstrumentWrites) return NULL;
+ *IsWrite = true;
+ return SI->getPointerOperand();
+ }
+ if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
+ if (!ClInstrumentAtomics) return NULL;
+ *IsWrite = true;
+ return RMW->getPointerOperand();
+ }
+ if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
+ if (!ClInstrumentAtomics) return NULL;
+ *IsWrite = true;
+ return XCHG->getPointerOperand();
+ }
+ return NULL;
+}
+
+void AddressSanitizer::FindDynamicInitializers(Module& M) {
+ // Clang generates metadata identifying all dynamically initialized globals.
+ NamedMDNode *DynamicGlobals =
+ M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
+ if (!DynamicGlobals)
+ return;
+ for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
+ MDNode *MDN = DynamicGlobals->getOperand(i);
+ assert(MDN->getNumOperands() == 1);
+ Value *VG = MDN->getOperand(0);
+ // The optimizer may optimize away a global entirely, in which case we
+ // cannot instrument access to it.
+ if (!VG)
+ continue;
+
+ GlobalVariable *G = cast<GlobalVariable>(VG);
+ DynamicallyInitializedGlobals.insert(G);
+ }
+}
+// Returns true if a global variable is initialized dynamically in this TU.
+bool AddressSanitizer::HasDynamicInitializer(GlobalVariable *G) {
+ return DynamicallyInitializedGlobals.count(G);
+}
+
+void AddressSanitizer::instrumentMop(Instruction *I) {
+ bool IsWrite = false;
+ Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
+ assert(Addr);
+ if (ClOpt && ClOptGlobals) {
+ if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
+ // If initialization order checking is disabled, a simple access to a
+ // dynamically initialized global is always valid.
+ if (!ClInitializers)
+ return;
+ // If a global variable does not have dynamic initialization we don't
+ // have to instrument it. However, if a global has external linkage, we
+ // assume it has dynamic initialization, as it may have an initializer
+ // in a different TU.
+ if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
+ !HasDynamicInitializer(G))
+ return;
+ }
+ }
+
+ Type *OrigPtrTy = Addr->getType();
+ Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
+
+ assert(OrigTy->isSized());
+ uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
+
+ if (TypeSize != 8 && TypeSize != 16 &&
+ TypeSize != 32 && TypeSize != 64 && TypeSize != 128) {
+ // Ignore all unusual sizes.
+ return;
+ }
+
+ IRBuilder<> IRB(I);
+ instrumentAddress(I, IRB, Addr, TypeSize, IsWrite);
+}
+
+// Validate the result of Module::getOrInsertFunction called for an interface
+// function of AddressSanitizer. If the instrumented module defines a function
+// with the same name, their prototypes must match, otherwise
+// getOrInsertFunction returns a bitcast.
+Function *AddressSanitizer::checkInterfaceFunction(Constant *FuncOrBitcast) {
+ if (isa<Function>(FuncOrBitcast)) return cast<Function>(FuncOrBitcast);
+ FuncOrBitcast->dump();
+ report_fatal_error("trying to redefine an AddressSanitizer "
+ "interface function");
+}
+
+Instruction *AddressSanitizer::generateCrashCode(
+ Instruction *InsertBefore, Value *Addr,
+ bool IsWrite, size_t AccessSizeIndex) {
+ IRBuilder<> IRB(InsertBefore);
+ CallInst *Call = IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex],
+ Addr);
+ // We don't do Call->setDoesNotReturn() because the BB already has
+ // UnreachableInst at the end.
+ // This EmptyAsm is required to avoid callback merge.
+ IRB.CreateCall(EmptyAsm);
+ return Call;
+}
+
+Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
+ Value *ShadowValue,
+ uint32_t TypeSize) {
+ size_t Granularity = 1 << MappingScale;
+ // Addr & (Granularity - 1)
+ Value *LastAccessedByte = IRB.CreateAnd(
+ AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
+ // (Addr & (Granularity - 1)) + size - 1
+ if (TypeSize / 8 > 1)
+ LastAccessedByte = IRB.CreateAdd(
+ LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
+ // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
+ LastAccessedByte = IRB.CreateIntCast(
+ LastAccessedByte, ShadowValue->getType(), false);
+ // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
+ return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
+}
+
+void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
+ IRBuilder<> &IRB, Value *Addr,
+ uint32_t TypeSize, bool IsWrite) {
+ Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
+
+ Type *ShadowTy = IntegerType::get(
+ *C, std::max(8U, TypeSize >> MappingScale));
+ Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
+ Value *ShadowPtr = memToShadow(AddrLong, IRB);
+ Value *CmpVal = Constant::getNullValue(ShadowTy);
+ Value *ShadowValue = IRB.CreateLoad(
+ IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
+
+ Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
+ size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
+ size_t Granularity = 1 << MappingScale;
+ TerminatorInst *CrashTerm = 0;
+
+ if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
+ TerminatorInst *CheckTerm =
+ SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
+ assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
+ BasicBlock *NextBB = CheckTerm->getSuccessor(0);
+ IRB.SetInsertPoint(CheckTerm);
+ Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
+ BasicBlock *CrashBlock =
+ BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
+ CrashTerm = new UnreachableInst(*C, CrashBlock);
+ BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
+ ReplaceInstWithInst(CheckTerm, NewTerm);
+ } else {
+ CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
+ }
+
+ Instruction *Crash =
+ generateCrashCode(CrashTerm, AddrLong, IsWrite, AccessSizeIndex);
+ Crash->setDebugLoc(OrigIns->getDebugLoc());
+}
+
+void AddressSanitizer::createInitializerPoisonCalls(Module &M,
+ Value *FirstAddr,
+ Value *LastAddr) {
+ // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
+ Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
+ // If that function is not present, this TU contains no globals, or they have
+ // all been optimized away
+ if (!GlobalInit)
+ return;
+
+ // Set up the arguments to our poison/unpoison functions.
+ IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
+
+ // Declare our poisoning and unpoisoning functions.
+ Function *AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
+ Function *AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
+ AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
+
+ // Add a call to poison all external globals before the given function starts.
+ IRB.CreateCall2(AsanPoisonGlobals, FirstAddr, LastAddr);
+
+ // Add calls to unpoison all globals before each return instruction.
+ for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
+ I != E; ++I) {
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
+ CallInst::Create(AsanUnpoisonGlobals, "", RI);
+ }
+ }
+}
+
+bool AddressSanitizer::ShouldInstrumentGlobal(GlobalVariable *G) {
+ Type *Ty = cast<PointerType>(G->getType())->getElementType();
+ DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
+
+ if (BL->isIn(*G)) return false;
+ if (!Ty->isSized()) return false;
+ if (!G->hasInitializer()) return false;
+ if (GlobalsCreatedByAsan.count(G)) return false; // Our own global.
+ // Touch only those globals that will not be defined in other modules.
+ // Don't handle ODR type linkages since other modules may be built w/o asan.
+ if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
+ G->getLinkage() != GlobalVariable::PrivateLinkage &&
+ G->getLinkage() != GlobalVariable::InternalLinkage)
+ return false;
+ // Two problems with thread-locals:
+ // - The address of the main thread's copy can't be computed at link-time.
+ // - Need to poison all copies, not just the main thread's one.
+ if (G->isThreadLocal())
+ return false;
+ // For now, just ignore this Alloca if the alignment is large.
+ if (G->getAlignment() > RedzoneSize) return false;
+
+ // Ignore all the globals with the names starting with "\01L_OBJC_".
+ // Many of those are put into the .cstring section. The linker compresses
+ // that section by removing the spare \0s after the string terminator, so
+ // our redzones get broken.
+ if ((G->getName().find("\01L_OBJC_") == 0) ||
+ (G->getName().find("\01l_OBJC_") == 0)) {
+ DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
+ return false;
+ }
+
+ if (G->hasSection()) {
+ StringRef Section(G->getSection());
+ // Ignore the globals from the __OBJC section. The ObjC runtime assumes
+ // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
+ // them.
+ if ((Section.find("__OBJC,") == 0) ||
+ (Section.find("__DATA, __objc_") == 0)) {
+ DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
+ return false;
+ }
+ // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
+ // Constant CFString instances are compiled in the following way:
+ // -- the string buffer is emitted into
+ // __TEXT,__cstring,cstring_literals
+ // -- the constant NSConstantString structure referencing that buffer
+ // is placed into __DATA,__cfstring
+ // Therefore there's no point in placing redzones into __DATA,__cfstring.
+ // Moreover, it causes the linker to crash on OS X 10.7
+ if (Section.find("__DATA,__cfstring") == 0) {
+ DEBUG(dbgs() << "Ignoring CFString: " << *G);
+ return false;
+ }
+ }
+
+ return true;
+}
+
+// This function replaces all global variables with new variables that have
+// trailing redzones. It also creates a function that poisons
+// redzones and inserts this function into llvm.global_ctors.
+bool AddressSanitizer::insertGlobalRedzones(Module &M) {
+ SmallVector<GlobalVariable *, 16> GlobalsToChange;
+
+ for (Module::GlobalListType::iterator G = M.global_begin(),
+ E = M.global_end(); G != E; ++G) {
+ if (ShouldInstrumentGlobal(G))
+ GlobalsToChange.push_back(G);
+ }
+
+ size_t n = GlobalsToChange.size();
+ if (n == 0) return false;
+
+ // A global is described by a structure
+ // size_t beg;
+ // size_t size;
+ // size_t size_with_redzone;
+ // const char *name;
+ // size_t has_dynamic_init;
+ // We initialize an array of such structures and pass it to a run-time call.
+ StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
+ IntptrTy, IntptrTy,
+ IntptrTy, NULL);
+ SmallVector<Constant *, 16> Initializers(n), DynamicInit;
+
+ IRBuilder<> IRB(CtorInsertBefore);
+
+ if (ClInitializers)
+ FindDynamicInitializers(M);
+
+ // The addresses of the first and last dynamically initialized globals in
+ // this TU. Used in initialization order checking.
+ Value *FirstDynamic = 0, *LastDynamic = 0;
+
+ for (size_t i = 0; i < n; i++) {
+ GlobalVariable *G = GlobalsToChange[i];
+ PointerType *PtrTy = cast<PointerType>(G->getType());
+ Type *Ty = PtrTy->getElementType();
+ uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
+ uint64_t RightRedzoneSize = RedzoneSize +
+ (RedzoneSize - (SizeInBytes % RedzoneSize));
+ Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
+ // Determine whether this global should be poisoned in initialization.
+ bool GlobalHasDynamicInitializer = HasDynamicInitializer(G);
+ // Don't check initialization order if this global is blacklisted.
+ GlobalHasDynamicInitializer &= !BL->isInInit(*G);
+
+ StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
+ Constant *NewInitializer = ConstantStruct::get(
+ NewTy, G->getInitializer(),
+ Constant::getNullValue(RightRedZoneTy), NULL);
+
+ SmallString<2048> DescriptionOfGlobal = G->getName();
+ DescriptionOfGlobal += " (";
+ DescriptionOfGlobal += M.getModuleIdentifier();
+ DescriptionOfGlobal += ")";
+ GlobalVariable *Name = createPrivateGlobalForString(M, DescriptionOfGlobal);
+
+ // Create a new global variable with enough space for a redzone.
+ GlobalVariable *NewGlobal = new GlobalVariable(
+ M, NewTy, G->isConstant(), G->getLinkage(),
+ NewInitializer, "", G, G->getThreadLocalMode());
+ NewGlobal->copyAttributesFrom(G);
+ NewGlobal->setAlignment(RedzoneSize);
+
+ Value *Indices2[2];
+ Indices2[0] = IRB.getInt32(0);
+ Indices2[1] = IRB.getInt32(0);
+
+ G->replaceAllUsesWith(
+ ConstantExpr::getGetElementPtr(NewGlobal, Indices2, true));
+ NewGlobal->takeName(G);
+ G->eraseFromParent();
+
+ Initializers[i] = ConstantStruct::get(
+ GlobalStructTy,
+ ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
+ ConstantInt::get(IntptrTy, SizeInBytes),
+ ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
+ ConstantExpr::getPointerCast(Name, IntptrTy),
+ ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
+ NULL);
+
+ // Populate the first and last globals declared in this TU.
+ if (ClInitializers && GlobalHasDynamicInitializer) {
+ LastDynamic = ConstantExpr::getPointerCast(NewGlobal, IntptrTy);
+ if (FirstDynamic == 0)
+ FirstDynamic = LastDynamic;
+ }
+
+ DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
+ }
+
+ ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
+ GlobalVariable *AllGlobals = new GlobalVariable(
+ M, ArrayOfGlobalStructTy, false, GlobalVariable::PrivateLinkage,
+ ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
+
+ // Create calls for poisoning before initializers run and unpoisoning after.
+ if (ClInitializers && FirstDynamic && LastDynamic)
+ createInitializerPoisonCalls(M, FirstDynamic, LastDynamic);
+
+ Function *AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanRegisterGlobalsName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, NULL));
+ AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
+
+ IRB.CreateCall2(AsanRegisterGlobals,
+ IRB.CreatePointerCast(AllGlobals, IntptrTy),
+ ConstantInt::get(IntptrTy, n));
+
+ // We also need to unregister globals at the end, e.g. when a shared library
+ // gets closed.
+ Function *AsanDtorFunction = Function::Create(
+ FunctionType::get(Type::getVoidTy(*C), false),
+ GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
+ BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
+ IRBuilder<> IRB_Dtor(ReturnInst::Create(*C, AsanDtorBB));
+ Function *AsanUnregisterGlobals =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanUnregisterGlobalsName,
+ IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
+
+ IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
+ IRB.CreatePointerCast(AllGlobals, IntptrTy),
+ ConstantInt::get(IntptrTy, n));
+ appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
+
+ DEBUG(dbgs() << M);
+ return true;
+}
+
+// virtual
+bool AddressSanitizer::doInitialization(Module &M) {
+ // Initialize the private fields. No one has accessed them before.
+ TD = getAnalysisIfAvailable<DataLayout>();
+
+ if (!TD)
+ return false;
+ BL.reset(new BlackList(ClBlackListFile));
+
+ C = &(M.getContext());
+ LongSize = TD->getPointerSizeInBits();
+ IntptrTy = Type::getIntNTy(*C, LongSize);
+ IntptrPtrTy = PointerType::get(IntptrTy, 0);
+
+ AsanCtorFunction = Function::Create(
+ FunctionType::get(Type::getVoidTy(*C), false),
+ GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
+ BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
+ CtorInsertBefore = ReturnInst::Create(*C, AsanCtorBB);
+
+ // call __asan_init in the module ctor.
+ IRBuilder<> IRB(CtorInsertBefore);
+ AsanInitFunction = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
+ AsanInitFunction->setLinkage(Function::ExternalLinkage);
+ IRB.CreateCall(AsanInitFunction);
+
+ // Create __asan_report* callbacks.
+ for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
+ for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
+ AccessSizeIndex++) {
+ // IsWrite and TypeSize are encoded in the function name.
+ std::string FunctionName = std::string(kAsanReportErrorTemplate) +
+ (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
+ // If we are merging crash callbacks, they have two parameters.
+ AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
+ }
+ }
+
+ AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
+ AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanStackFreeName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, IntptrTy, NULL));
+ AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
+
+ // We insert an empty inline asm after __asan_report* to avoid callback merge.
+ EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
+ StringRef(""), StringRef(""),
+ /*hasSideEffects=*/true);
+
+ llvm::Triple targetTriple(M.getTargetTriple());
+ bool isAndroid = targetTriple.getEnvironment() == llvm::Triple::Android;
+
+ MappingOffset = isAndroid ? kDefaultShadowOffsetAndroid :
+ (LongSize == 32 ? kDefaultShadowOffset32 : kDefaultShadowOffset64);
+ if (ClMappingOffsetLog >= 0) {
+ if (ClMappingOffsetLog == 0) {
+ // special case
+ MappingOffset = 0;
+ } else {
+ MappingOffset = 1ULL << ClMappingOffsetLog;
+ }
+ }
+ MappingScale = kDefaultShadowScale;
+ if (ClMappingScale) {
+ MappingScale = ClMappingScale;
+ }
+ // Redzone used for stack and globals is at least 32 bytes.
+ // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
+ RedzoneSize = std::max(32, (int)(1 << MappingScale));
+
+
+ if (ClMappingOffsetLog >= 0) {
+ // Tell the run-time the current values of mapping offset and scale.
+ GlobalValue *asan_mapping_offset =
+ new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
+ ConstantInt::get(IntptrTy, MappingOffset),
+ kAsanMappingOffsetName);
+ // Read the global, otherwise it may be optimized away.
+ IRB.CreateLoad(asan_mapping_offset, true);
+ }
+ if (ClMappingScale) {
+ GlobalValue *asan_mapping_scale =
+ new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
+ ConstantInt::get(IntptrTy, MappingScale),
+ kAsanMappingScaleName);
+ // Read the global, otherwise it may be optimized away.
+ IRB.CreateLoad(asan_mapping_scale, true);
+ }
+
+ appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
+
+ return true;
+}
+
+bool AddressSanitizer::doFinalization(Module &M) {
+ // We transform the globals at the very end so that the optimization analysis
+ // works on the original globals.
+ if (ClGlobals)
+ return insertGlobalRedzones(M);
+ return false;
+}
+
+
+bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
+ // For each NSObject descendant having a +load method, this method is invoked
+ // by the ObjC runtime before any of the static constructors is called.
+ // Therefore we need to instrument such methods with a call to __asan_init
+ // at the beginning in order to initialize our runtime before any access to
+ // the shadow memory.
+ // We cannot just ignore these methods, because they may call other
+ // instrumented functions.
+ if (F.getName().find(" load]") != std::string::npos) {
+ IRBuilder<> IRB(F.begin()->begin());
+ IRB.CreateCall(AsanInitFunction);
+ return true;
+ }
+ return false;
+}
+
+bool AddressSanitizer::runOnFunction(Function &F) {
+ if (BL->isIn(F)) return false;
+ if (&F == AsanCtorFunction) return false;
+ DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
+
+ // If needed, insert __asan_init before checking for AddressSafety attr.
+ maybeInsertAsanInitAtFunctionEntry(F);
+
+ if (!F.getFnAttributes().hasAttribute(Attributes::AddressSafety))
+ return false;
+
+ if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
+ return false;
+
+ // We want to instrument every address only once per basic block (unless there
+ // are calls between uses).
+ SmallSet<Value*, 16> TempsToInstrument;
+ SmallVector<Instruction*, 16> ToInstrument;
+ SmallVector<Instruction*, 8> NoReturnCalls;
+ bool IsWrite;
+
+ // Fill the set of memory operations to instrument.
+ for (Function::iterator FI = F.begin(), FE = F.end();
+ FI != FE; ++FI) {
+ TempsToInstrument.clear();
+ int NumInsnsPerBB = 0;
+ for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
+ BI != BE; ++BI) {
+ if (LooksLikeCodeInBug11395(BI)) return false;
+ if (Value *Addr = isInterestingMemoryAccess(BI, &IsWrite)) {
+ if (ClOpt && ClOptSameTemp) {
+ if (!TempsToInstrument.insert(Addr))
+ continue; // We've seen this temp in the current BB.
+ }
+ } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
+ // ok, take it.
+ } else {
+ if (CallInst *CI = dyn_cast<CallInst>(BI)) {
+ // A call inside BB.
+ TempsToInstrument.clear();
+ if (CI->doesNotReturn()) {
+ NoReturnCalls.push_back(CI);
+ }
+ }
+ continue;
+ }
+ ToInstrument.push_back(BI);
+ NumInsnsPerBB++;
+ if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
+ break;
+ }
+ }
+
+ // Instrument.
+ int NumInstrumented = 0;
+ for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
+ Instruction *Inst = ToInstrument[i];
+ if (ClDebugMin < 0 || ClDebugMax < 0 ||
+ (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
+ if (isInterestingMemoryAccess(Inst, &IsWrite))
+ instrumentMop(Inst);
+ else
+ instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
+ }
+ NumInstrumented++;
+ }
+
+ bool ChangedStack = poisonStackInFunction(F);
+
+ // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
+ // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
+ for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
+ Instruction *CI = NoReturnCalls[i];
+ IRBuilder<> IRB(CI);
+ IRB.CreateCall(AsanHandleNoReturnFunc);
+ }
+ DEBUG(dbgs() << "ASAN done instrumenting:\n" << F << "\n");
+
+ return NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
+}
+
+static uint64_t ValueForPoison(uint64_t PoisonByte, size_t ShadowRedzoneSize) {
+ if (ShadowRedzoneSize == 1) return PoisonByte;
+ if (ShadowRedzoneSize == 2) return (PoisonByte << 8) + PoisonByte;
+ if (ShadowRedzoneSize == 4)
+ return (PoisonByte << 24) + (PoisonByte << 16) +
+ (PoisonByte << 8) + (PoisonByte);
+ llvm_unreachable("ShadowRedzoneSize is either 1, 2 or 4");
+}
+
+static void PoisonShadowPartialRightRedzone(uint8_t *Shadow,
+ size_t Size,
+ size_t RedzoneSize,
+ size_t ShadowGranularity,
+ uint8_t Magic) {
+ for (size_t i = 0; i < RedzoneSize;
+ i+= ShadowGranularity, Shadow++) {
+ if (i + ShadowGranularity <= Size) {
+ *Shadow = 0; // fully addressable
+ } else if (i >= Size) {
+ *Shadow = Magic; // unaddressable
+ } else {
+ *Shadow = Size - i; // first Size-i bytes are addressable
+ }
+ }
+}
+
+void AddressSanitizer::PoisonStack(const ArrayRef<AllocaInst*> &AllocaVec,
+ IRBuilder<> IRB,
+ Value *ShadowBase, bool DoPoison) {
+ size_t ShadowRZSize = RedzoneSize >> MappingScale;
+ assert(ShadowRZSize >= 1 && ShadowRZSize <= 4);
+ Type *RZTy = Type::getIntNTy(*C, ShadowRZSize * 8);
+ Type *RZPtrTy = PointerType::get(RZTy, 0);
+
+ Value *PoisonLeft = ConstantInt::get(RZTy,
+ ValueForPoison(DoPoison ? kAsanStackLeftRedzoneMagic : 0LL, ShadowRZSize));
+ Value *PoisonMid = ConstantInt::get(RZTy,
+ ValueForPoison(DoPoison ? kAsanStackMidRedzoneMagic : 0LL, ShadowRZSize));
+ Value *PoisonRight = ConstantInt::get(RZTy,
+ ValueForPoison(DoPoison ? kAsanStackRightRedzoneMagic : 0LL, ShadowRZSize));
+
+ // poison the first red zone.
+ IRB.CreateStore(PoisonLeft, IRB.CreateIntToPtr(ShadowBase, RZPtrTy));
+
+ // poison all other red zones.
+ uint64_t Pos = RedzoneSize;
+ for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
+ AllocaInst *AI = AllocaVec[i];
+ uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
+ uint64_t AlignedSize = getAlignedAllocaSize(AI);
+ assert(AlignedSize - SizeInBytes < RedzoneSize);
+ Value *Ptr = NULL;
+
+ Pos += AlignedSize;
+
+ assert(ShadowBase->getType() == IntptrTy);
+ if (SizeInBytes < AlignedSize) {
+ // Poison the partial redzone at right
+ Ptr = IRB.CreateAdd(
+ ShadowBase, ConstantInt::get(IntptrTy,
+ (Pos >> MappingScale) - ShadowRZSize));
+ size_t AddressableBytes = RedzoneSize - (AlignedSize - SizeInBytes);
+ uint32_t Poison = 0;
+ if (DoPoison) {
+ PoisonShadowPartialRightRedzone((uint8_t*)&Poison, AddressableBytes,
+ RedzoneSize,
+ 1ULL << MappingScale,
+ kAsanStackPartialRedzoneMagic);
+ }
+ Value *PartialPoison = ConstantInt::get(RZTy, Poison);
+ IRB.CreateStore(PartialPoison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
+ }
+
+ // Poison the full redzone at right.
+ Ptr = IRB.CreateAdd(ShadowBase,
+ ConstantInt::get(IntptrTy, Pos >> MappingScale));
+ Value *Poison = i == AllocaVec.size() - 1 ? PoisonRight : PoisonMid;
+ IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, RZPtrTy));
+
+ Pos += RedzoneSize;
+ }
+}
+
+// Workaround for bug 11395: we don't want to instrument stack in functions
+// with large assembly blobs (32-bit only), otherwise reg alloc may crash.
+// FIXME: remove once the bug 11395 is fixed.
+bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
+ if (LongSize != 32) return false;
+ CallInst *CI = dyn_cast<CallInst>(I);
+ if (!CI || !CI->isInlineAsm()) return false;
+ if (CI->getNumArgOperands() <= 5) return false;
+ // We have inline assembly with quite a few arguments.
+ return true;
+}
+
+// Find all static Alloca instructions and put
+// poisoned red zones around all of them.
+// Then unpoison everything back before the function returns.
+//
+// Stack poisoning does not play well with exception handling.
+// When an exception is thrown, we essentially bypass the code
+// that unpoisones the stack. This is why the run-time library has
+// to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
+// stack in the interceptor. This however does not work inside the
+// actual function which catches the exception. Most likely because the
+// compiler hoists the load of the shadow value somewhere too high.
+// This causes asan to report a non-existing bug on 453.povray.
+// It sounds like an LLVM bug.
+bool AddressSanitizer::poisonStackInFunction(Function &F) {
+ if (!ClStack) return false;
+ SmallVector<AllocaInst*, 16> AllocaVec;
+ SmallVector<Instruction*, 8> RetVec;
+ uint64_t TotalSize = 0;
+
+ // Filter out Alloca instructions we want (and can) handle.
+ // Collect Ret instructions.
+ for (Function::iterator FI = F.begin(), FE = F.end();
+ FI != FE; ++FI) {
+ BasicBlock &BB = *FI;
+ for (BasicBlock::iterator BI = BB.begin(), BE = BB.end();
+ BI != BE; ++BI) {
+ if (isa<ReturnInst>(BI)) {
+ RetVec.push_back(BI);
+ continue;
+ }
+
+ AllocaInst *AI = dyn_cast<AllocaInst>(BI);
+ if (!AI) continue;
+ if (AI->isArrayAllocation()) continue;
+ if (!AI->isStaticAlloca()) continue;
+ if (!AI->getAllocatedType()->isSized()) continue;
+ if (AI->getAlignment() > RedzoneSize) continue;
+ AllocaVec.push_back(AI);
+ uint64_t AlignedSize = getAlignedAllocaSize(AI);
+ TotalSize += AlignedSize;
+ }
+ }
+
+ if (AllocaVec.empty()) return false;
+
+ uint64_t LocalStackSize = TotalSize + (AllocaVec.size() + 1) * RedzoneSize;
+
+ bool DoStackMalloc = ClUseAfterReturn
+ && LocalStackSize <= kMaxStackMallocSize;
+
+ Instruction *InsBefore = AllocaVec[0];
+ IRBuilder<> IRB(InsBefore);
+
+
+ Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
+ AllocaInst *MyAlloca =
+ new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
+ MyAlloca->setAlignment(RedzoneSize);
+ assert(MyAlloca->isStaticAlloca());
+ Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
+ Value *LocalStackBase = OrigStackBase;
+
+ if (DoStackMalloc) {
+ LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
+ ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
+ }
+
+ // This string will be parsed by the run-time (DescribeStackAddress).
+ SmallString<2048> StackDescriptionStorage;
+ raw_svector_ostream StackDescription(StackDescriptionStorage);
+ StackDescription << F.getName() << " " << AllocaVec.size() << " ";
+
+ uint64_t Pos = RedzoneSize;
+ // Replace Alloca instructions with base+offset.
+ for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
+ AllocaInst *AI = AllocaVec[i];
+ uint64_t SizeInBytes = getAllocaSizeInBytes(AI);
+ StringRef Name = AI->getName();
+ StackDescription << Pos << " " << SizeInBytes << " "
+ << Name.size() << " " << Name << " ";
+ uint64_t AlignedSize = getAlignedAllocaSize(AI);
+ assert((AlignedSize % RedzoneSize) == 0);
+ AI->replaceAllUsesWith(
+ IRB.CreateIntToPtr(
+ IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Pos)),
+ AI->getType()));
+ Pos += AlignedSize + RedzoneSize;
+ }
+ assert(Pos == LocalStackSize);
+
+ // Write the Magic value and the frame description constant to the redzone.
+ Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
+ IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
+ BasePlus0);
+ Value *BasePlus1 = IRB.CreateAdd(LocalStackBase,
+ ConstantInt::get(IntptrTy, LongSize/8));
+ BasePlus1 = IRB.CreateIntToPtr(BasePlus1, IntptrPtrTy);
+ GlobalVariable *StackDescriptionGlobal =
+ createPrivateGlobalForString(*F.getParent(), StackDescription.str());
+ GlobalsCreatedByAsan.insert(StackDescriptionGlobal);
+ Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
+ IRB.CreateStore(Description, BasePlus1);
+
+ // Poison the stack redzones at the entry.
+ Value *ShadowBase = memToShadow(LocalStackBase, IRB);
+ PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRB, ShadowBase, true);
+
+ // Unpoison the stack before all ret instructions.
+ for (size_t i = 0, n = RetVec.size(); i < n; i++) {
+ Instruction *Ret = RetVec[i];
+ IRBuilder<> IRBRet(Ret);
+
+ // Mark the current frame as retired.
+ IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
+ BasePlus0);
+ // Unpoison the stack.
+ PoisonStack(ArrayRef<AllocaInst*>(AllocaVec), IRBRet, ShadowBase, false);
+
+ if (DoStackMalloc) {
+ IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
+ ConstantInt::get(IntptrTy, LocalStackSize),
+ OrigStackBase);
+ }
+ }
+
+ // We are done. Remove the old unused alloca instructions.
+ for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
+ AllocaVec[i]->eraseFromParent();
+
+ if (ClDebugStack) {
+ DEBUG(dbgs() << F);
+ }
+
+ return true;
+}
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