AddressSanitizer.cpp [plain text]
#define DEBUG_TYPE "asan"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/InstVisitor.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/system_error.h"
#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include "llvm/Transforms/Utils/SpecialCaseList.h"
#include <algorithm>
#include <string>
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 kDefaultShort64bitShadowOffset = 0x7FFF8000; static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000;
static const size_t kMinStackMallocSize = 1 << 6; static const size_t kMaxStackMallocSize = 1 << 16; static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
static const char *const kAsanModuleCtorName = "asan.module_ctor";
static const char *const kAsanModuleDtorName = "asan.module_dtor";
static const int kAsanCtorAndCtorPriority = 1;
static const char *const kAsanReportErrorTemplate = "__asan_report_";
static const char *const kAsanReportLoadN = "__asan_report_load_n";
static const char *const kAsanReportStoreN = "__asan_report_store_n";
static const char *const kAsanRegisterGlobalsName = "__asan_register_globals";
static const char *const kAsanUnregisterGlobalsName =
"__asan_unregister_globals";
static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
static const char *const kAsanInitName = "__asan_init_v3";
static const char *const kAsanCovName = "__sanitizer_cov";
static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
static const char *const kAsanMappingOffsetName = "__asan_mapping_offset";
static const char *const kAsanMappingScaleName = "__asan_mapping_scale";
static const int kMaxAsanStackMallocSizeClass = 10;
static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
static const char *const kAsanGenPrefix = "__asan_gen_";
static const char *const kAsanPoisonStackMemoryName =
"__asan_poison_stack_memory";
static const char *const kAsanUnpoisonStackMemoryName =
"__asan_unpoison_stack_memory";
static const char *const kAsanOptionDetectUAR =
"__asan_option_detect_stack_use_after_return";
#ifndef NDEBUG
static const int kAsanStackAfterReturnMagic = 0xf5;
#endif
static const size_t kNumberOfAccessSizes = 5;
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));
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);
static cl::opt<bool> ClStack("asan-stack",
cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
cl::desc("Check return-after-free"), cl::Hidden, cl::init(false));
static cl::opt<bool> ClGlobals("asan-globals",
cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
static cl::opt<int> ClCoverage("asan-coverage",
cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks"),
cl::Hidden, cl::init(false));
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));
static cl::opt<unsigned> ClRealignStack("asan-realign-stack",
cl::desc("Realign stack to the value of this flag (power of two)"),
cl::Hidden, cl::init(32));
static cl::opt<std::string> ClBlacklistFile("asan-blacklist",
cl::desc("File containing the list of objects to ignore "
"during instrumentation"), cl::Hidden);
static cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions",
cl::desc("Keep uninstrumented copies of functions"),
cl::Hidden, cl::init(false));
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));
static cl::opt<bool> ClShort64BitOffset("asan-short-64bit-mapping-offset",
cl::desc("Use short immediate constant as the mapping offset for 64bit"),
cl::Hidden, cl::init(true));
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));
static cl::opt<bool> ClCheckLifetime("asan-check-lifetime",
cl::desc("Use llvm.lifetime intrinsics to insert extra checks"),
cl::Hidden, cl::init(false));
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));
STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
STATISTIC(NumOptimizedAccessesToGlobalArray,
"Number of optimized accesses to global arrays");
STATISTIC(NumOptimizedAccessesToGlobalVar,
"Number of optimized accesses to global vars");
namespace {
class SetOfDynamicallyInitializedGlobals {
public:
void Init(Module& M) {
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);
if (!VG)
continue;
DynInitGlobals.insert(cast<GlobalVariable>(VG));
}
}
bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
private:
SmallSet<GlobalValue*, 32> DynInitGlobals;
};
struct ShadowMapping {
int Scale;
uint64_t Offset;
bool OrShadowOffset;
};
static ShadowMapping getShadowMapping(const Module &M, int LongSize) {
llvm::Triple TargetTriple(M.getTargetTriple());
bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
bool IsMacOSX = TargetTriple.getOS() == llvm::Triple::MacOSX;
bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
TargetTriple.getArch() == llvm::Triple::ppc64le;
bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
TargetTriple.getArch() == llvm::Triple::mipsel;
ShadowMapping Mapping;
Mapping.OrShadowOffset = !IsPPC64 && !ClShort64BitOffset;
Mapping.Offset = IsAndroid ? 0 :
(LongSize == 32 ?
(IsMIPS32 ? kMIPS32_ShadowOffset32 : kDefaultShadowOffset32) :
IsPPC64 ? kPPC64_ShadowOffset64 : kDefaultShadowOffset64);
if (!IsAndroid && ClShort64BitOffset && IsX86_64 && !IsMacOSX) {
assert(LongSize == 64);
Mapping.Offset = kDefaultShort64bitShadowOffset;
}
if (!IsAndroid && ClMappingOffsetLog >= 0) {
Mapping.Offset = (ClMappingOffsetLog == 0) ? 0 : 1ULL << ClMappingOffsetLog;
}
Mapping.Scale = kDefaultShadowScale;
if (ClMappingScale) {
Mapping.Scale = ClMappingScale;
}
return Mapping;
}
static size_t RedzoneSizeForScale(int MappingScale) {
return std::max(32U, 1U << MappingScale);
}
struct AddressSanitizer : public FunctionPass {
AddressSanitizer(bool CheckInitOrder = true,
bool CheckUseAfterReturn = false,
bool CheckLifetime = false,
StringRef BlacklistFile = StringRef())
: FunctionPass(ID),
CheckInitOrder(CheckInitOrder || ClInitializers),
CheckUseAfterReturn(CheckUseAfterReturn || ClUseAfterReturn),
CheckLifetime(CheckLifetime || ClCheckLifetime),
BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
: BlacklistFile) {}
virtual const char *getPassName() const {
return "AddressSanitizerFunctionPass";
}
void instrumentMop(Instruction *I);
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
Value *Addr, uint32_t TypeSize, bool IsWrite,
Value *SizeArgument);
Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
Value *ShadowValue, uint32_t TypeSize);
Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
bool IsWrite, size_t AccessSizeIndex,
Value *SizeArgument);
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);
bool maybeInsertAsanInitAtFunctionEntry(Function &F);
void emitShadowMapping(Module &M, IRBuilder<> &IRB) const;
virtual bool doInitialization(Module &M);
static char ID;
private:
void initializeCallbacks(Module &M);
bool ShouldInstrumentGlobal(GlobalVariable *G);
bool LooksLikeCodeInBug11395(Instruction *I);
void FindDynamicInitializers(Module &M);
bool GlobalIsLinkerInitialized(GlobalVariable *G);
bool InjectCoverage(Function &F, const ArrayRef<BasicBlock*> AllBlocks);
void InjectCoverageAtBlock(Function &F, BasicBlock &BB);
bool CheckInitOrder;
bool CheckUseAfterReturn;
bool CheckLifetime;
SmallString<64> BlacklistFile;
LLVMContext *C;
DataLayout *TD;
int LongSize;
Type *IntptrTy;
ShadowMapping Mapping;
Function *AsanCtorFunction;
Function *AsanInitFunction;
Function *AsanHandleNoReturnFunc;
Function *AsanCovFunction;
OwningPtr<SpecialCaseList> BL;
Function *AsanErrorCallback[2][kNumberOfAccessSizes];
Function *AsanErrorCallbackSized[2];
InlineAsm *EmptyAsm;
SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
friend struct FunctionStackPoisoner;
};
class AddressSanitizerModule : public ModulePass {
public:
AddressSanitizerModule(bool CheckInitOrder = true,
StringRef BlacklistFile = StringRef())
: ModulePass(ID),
CheckInitOrder(CheckInitOrder || ClInitializers),
BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
: BlacklistFile) {}
bool runOnModule(Module &M);
static char ID; virtual const char *getPassName() const {
return "AddressSanitizerModule";
}
private:
void initializeCallbacks(Module &M);
bool ShouldInstrumentGlobal(GlobalVariable *G);
void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
size_t MinRedzoneSizeForGlobal() const {
return RedzoneSizeForScale(Mapping.Scale);
}
bool CheckInitOrder;
SmallString<64> BlacklistFile;
OwningPtr<SpecialCaseList> BL;
SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
Type *IntptrTy;
LLVMContext *C;
DataLayout *TD;
ShadowMapping Mapping;
Function *AsanPoisonGlobals;
Function *AsanUnpoisonGlobals;
Function *AsanRegisterGlobals;
Function *AsanUnregisterGlobals;
};
struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
Function &F;
AddressSanitizer &ASan;
DIBuilder DIB;
LLVMContext *C;
Type *IntptrTy;
Type *IntptrPtrTy;
ShadowMapping Mapping;
SmallVector<AllocaInst*, 16> AllocaVec;
SmallVector<Instruction*, 8> RetVec;
unsigned StackAlignment;
Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
*AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
struct AllocaPoisonCall {
IntrinsicInst *InsBefore;
AllocaInst *AI;
uint64_t Size;
bool DoPoison;
};
SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec;
typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy;
AllocaForValueMapTy AllocaForValue;
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
: F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C),
IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)),
Mapping(ASan.Mapping),
StackAlignment(1 << Mapping.Scale) {}
bool runOnFunction() {
if (!ClStack) return false;
for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
BasicBlock *BB = *DI;
visit(*BB);
}
if (AllocaVec.empty()) return false;
initializeCallbacks(*F.getParent());
poisonStack();
if (ClDebugStack) {
DEBUG(dbgs() << F);
}
return true;
}
void poisonStack();
void visitReturnInst(ReturnInst &RI) {
RetVec.push_back(&RI);
}
void visitAllocaInst(AllocaInst &AI) {
if (!isInterestingAlloca(AI)) return;
StackAlignment = std::max(StackAlignment, AI.getAlignment());
AllocaVec.push_back(&AI);
}
void visitIntrinsicInst(IntrinsicInst &II) {
if (!ASan.CheckLifetime) return;
Intrinsic::ID ID = II.getIntrinsicID();
if (ID != Intrinsic::lifetime_start &&
ID != Intrinsic::lifetime_end)
return;
ConstantInt *Size = dyn_cast<ConstantInt>(II.getArgOperand(0));
if (Size->isMinusOne()) return;
const uint64_t SizeValue = Size->getValue().getLimitedValue();
if (SizeValue == ~0ULL ||
!ConstantInt::isValueValidForType(IntptrTy, SizeValue))
return;
AllocaInst *AI = findAllocaForValue(II.getArgOperand(1));
if (!AI) return;
bool DoPoison = (ID == Intrinsic::lifetime_end);
AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison};
AllocaPoisonCallVec.push_back(APC);
}
void initializeCallbacks(Module &M);
bool isInterestingAlloca(AllocaInst &AI) const {
return (!AI.isArrayAllocation() && AI.isStaticAlloca() &&
AI.getAllocatedType()->isSized() &&
getAllocaSizeInBytes(&AI) > 0);
}
uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
Type *Ty = AI->getAllocatedType();
uint64_t SizeInBytes = ASan.TD->getTypeAllocSize(Ty);
return SizeInBytes;
}
AllocaInst *findAllocaForValue(Value *V);
void poisonRedZones(const ArrayRef<uint8_t> ShadowBytes, IRBuilder<> &IRB,
Value *ShadowBase, bool DoPoison);
void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison);
void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase,
int Size);
};
}
char AddressSanitizer::ID = 0;
INITIALIZE_PASS(AddressSanitizer, "asan",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
false, false)
FunctionPass *llvm::createAddressSanitizerFunctionPass(
bool CheckInitOrder, bool CheckUseAfterReturn, bool CheckLifetime,
StringRef BlacklistFile) {
return new AddressSanitizer(CheckInitOrder, CheckUseAfterReturn,
CheckLifetime, BlacklistFile);
}
char AddressSanitizerModule::ID = 0;
INITIALIZE_PASS(AddressSanitizerModule, "asan-module",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
"ModulePass", false, false)
ModulePass *llvm::createAddressSanitizerModulePass(
bool CheckInitOrder, StringRef BlacklistFile) {
return new AddressSanitizerModule(CheckInitOrder, BlacklistFile);
}
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
size_t Res = countTrailingZeros(TypeSize / 8);
assert(Res < kNumberOfAccessSizes);
return Res;
}
static GlobalVariable *createPrivateGlobalForString(
Module &M, StringRef Str, bool AllowMerging) {
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
GlobalVariable *GV =
new GlobalVariable(M, StrConst->getType(), true,
GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
if (AllowMerging)
GV->setUnnamedAddr(true);
GV->setAlignment(1); return GV;
}
static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
return G->getName().find(kAsanGenPrefix) == 0;
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
if (Mapping.Offset == 0)
return Shadow;
if (Mapping.OrShadowOffset)
return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
else
return IRB.CreateAdd(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
}
void AddressSanitizer::instrumentMemIntrinsicParam(
Instruction *OrigIns,
Value *Addr, Value *Size, Instruction *InsertBefore, bool IsWrite) {
IRBuilder<> IRB(InsertBefore);
if (Size->getType() != IntptrTy)
Size = IRB.CreateIntCast(Size, IntptrTy, false);
instrumentAddress(OrigIns, InsertBefore, Addr, 8, IsWrite, Size);
IRB.SetInsertPoint(InsertBefore);
Value *SizeMinusOne = IRB.CreateSub(Size, ConstantInt::get(IntptrTy, 1));
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
Value *AddrLast = IRB.CreateAdd(AddrLong, SizeMinusOne);
instrumentAddress(OrigIns, InsertBefore, AddrLast, 8, IsWrite, Size);
}
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 {
IRBuilder<> IRB(InsertBefore);
Value *Cmp = IRB.CreateICmpNE(Length,
Constant::getNullValue(Length->getType()));
InsertBefore = SplitBlockAndInsertIfThen(Cmp, InsertBefore, false);
}
instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
if (Src)
instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
return true;
}
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;
}
bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
return G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(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 (!CheckInitOrder || GlobalIsLinkerInitialized(G)) {
NumOptimizedAccessesToGlobalVar++;
return;
}
}
ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr);
if (CE && CE->isGEPWithNoNotionalOverIndexing()) {
if (GlobalVariable *G = dyn_cast<GlobalVariable>(CE->getOperand(0))) {
if (CE->getOperand(1)->isNullValue() && GlobalIsLinkerInitialized(G)) {
NumOptimizedAccessesToGlobalArray++;
return;
}
}
}
}
Type *OrigPtrTy = Addr->getType();
Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
assert(OrigTy->isSized());
uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
assert((TypeSize % 8) == 0);
if (IsWrite)
NumInstrumentedWrites++;
else
NumInstrumentedReads++;
if (TypeSize == 8 || TypeSize == 16 ||
TypeSize == 32 || TypeSize == 64 || TypeSize == 128)
return instrumentAddress(I, I, Addr, TypeSize, IsWrite, 0);
IRBuilder<> IRB(I);
Value *LastByte = IRB.CreateIntToPtr(
IRB.CreateAdd(IRB.CreatePointerCast(Addr, IntptrTy),
ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
OrigPtrTy);
Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
instrumentAddress(I, I, Addr, 8, IsWrite, Size);
instrumentAddress(I, I, LastByte, 8, IsWrite, Size);
}
static Function *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, Value *SizeArgument) {
IRBuilder<> IRB(InsertBefore);
CallInst *Call = SizeArgument
? IRB.CreateCall2(AsanErrorCallbackSized[IsWrite], Addr, SizeArgument)
: IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
IRB.CreateCall(EmptyAsm);
return Call;
}
Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
Value *ShadowValue,
uint32_t TypeSize) {
size_t Granularity = 1 << Mapping.Scale;
Value *LastAccessedByte = IRB.CreateAnd(
AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
if (TypeSize / 8 > 1)
LastAccessedByte = IRB.CreateAdd(
LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
LastAccessedByte = IRB.CreateIntCast(
LastAccessedByte, ShadowValue->getType(), false);
return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
}
void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
Instruction *InsertBefore,
Value *Addr, uint32_t TypeSize,
bool IsWrite, Value *SizeArgument) {
IRBuilder<> IRB(InsertBefore);
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
Type *ShadowTy = IntegerType::get(
*C, std::max(8U, TypeSize >> Mapping.Scale));
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 << Mapping.Scale;
TerminatorInst *CrashTerm = 0;
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
TerminatorInst *CheckTerm =
SplitBlockAndInsertIfThen(Cmp, InsertBefore, 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(Cmp, InsertBefore, true);
}
Instruction *Crash = generateCrashCode(
CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument);
Crash->setDebugLoc(OrigIns->getDebugLoc());
}
void AddressSanitizerModule::createInitializerPoisonCalls(
Module &M, GlobalValue *ModuleName) {
Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
if (!GlobalInit)
return;
IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr);
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 AddressSanitizerModule::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 (GlobalWasGeneratedByAsan(G)) return false; if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
G->getLinkage() != GlobalVariable::PrivateLinkage &&
G->getLinkage() != GlobalVariable::InternalLinkage)
return false;
if (G->isThreadLocal())
return false;
if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
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());
if ((Section.find("__OBJC,") == 0) ||
(Section.find("__DATA, __objc_") == 0)) {
DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
return false;
}
if (Section.find("__DATA,__cfstring") == 0) {
DEBUG(dbgs() << "Ignoring CFString: " << *G);
return false;
}
}
return true;
}
void AddressSanitizerModule::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL));
AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanRegisterGlobalsName, IRB.getVoidTy(),
IntptrTy, IntptrTy, NULL));
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanUnregisterGlobalsName,
IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
}
bool AddressSanitizerModule::runOnModule(Module &M) {
if (!ClGlobals) return false;
TD = getAnalysisIfAvailable<DataLayout>();
if (!TD)
return false;
BL.reset(SpecialCaseList::createOrDie(BlacklistFile));
if (BL->isIn(M)) return false;
C = &(M.getContext());
int LongSize = TD->getPointerSizeInBits();
IntptrTy = Type::getIntNTy(*C, LongSize);
Mapping = getShadowMapping(M, LongSize);
initializeCallbacks(M);
DynamicallyInitializedGlobals.Init(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;
StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
IntptrTy, IntptrTy,
IntptrTy, IntptrTy, NULL);
SmallVector<Constant *, 16> Initializers(n);
Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
assert(CtorFunc);
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
bool HasDynamicallyInitializedGlobals = false;
GlobalVariable *ModuleName = createPrivateGlobalForString(
M, M.getModuleIdentifier(), false);
for (size_t i = 0; i < n; i++) {
static const uint64_t kMaxGlobalRedzone = 1 << 18;
GlobalVariable *G = GlobalsToChange[i];
PointerType *PtrTy = cast<PointerType>(G->getType());
Type *Ty = PtrTy->getElementType();
uint64_t SizeInBytes = TD->getTypeAllocSize(Ty);
uint64_t MinRZ = MinRedzoneSizeForGlobal();
uint64_t RZ = std::max(MinRZ,
std::min(kMaxGlobalRedzone,
(SizeInBytes / MinRZ / 4) * MinRZ));
uint64_t RightRedzoneSize = RZ;
if (SizeInBytes % MinRZ)
RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
bool GlobalHasDynamicInitializer =
DynamicallyInitializedGlobals.Contains(G);
GlobalHasDynamicInitializer &= !BL->isIn(*G, "init");
StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
Constant *NewInitializer = ConstantStruct::get(
NewTy, G->getInitializer(),
Constant::getNullValue(RightRedZoneTy), NULL);
GlobalVariable *Name =
createPrivateGlobalForString(M, G->getName(), true);
GlobalValue::LinkageTypes Linkage = G->getLinkage();
if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
Linkage = GlobalValue::InternalLinkage;
GlobalVariable *NewGlobal = new GlobalVariable(
M, NewTy, G->isConstant(), Linkage,
NewInitializer, "", G, G->getThreadLocalMode());
NewGlobal->copyAttributesFrom(G);
NewGlobal->setAlignment(MinRZ);
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),
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
ConstantInt::get(IntptrTy, GlobalHasDynamicInitializer),
NULL);
if (CheckInitOrder && GlobalHasDynamicInitializer)
HasDynamicallyInitializedGlobals = true;
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
}
ArrayType *ArrayOfGlobalStructTy = ArrayType::get(GlobalStructTy, n);
GlobalVariable *AllGlobals = new GlobalVariable(
M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
if (CheckInitOrder && HasDynamicallyInitializedGlobals)
createInitializerPoisonCalls(M, ModuleName);
IRB.CreateCall2(AsanRegisterGlobals,
IRB.CreatePointerCast(AllGlobals, IntptrTy),
ConstantInt::get(IntptrTy, n));
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));
IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
IRB.CreatePointerCast(AllGlobals, IntptrTy),
ConstantInt::get(IntptrTy, n));
appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
DEBUG(dbgs() << M);
return true;
}
void AddressSanitizer::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
AccessSizeIndex++) {
std::string FunctionName = std::string(kAsanReportErrorTemplate) +
(AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
checkInterfaceFunction(M.getOrInsertFunction(
FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
}
}
AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction(
kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction(
kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction(
kAsanCovName, IRB.getVoidTy(), NULL));
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
true);
}
void AddressSanitizer::emitShadowMapping(Module &M, IRBuilder<> &IRB) const {
GlobalValue *asan_mapping_offset =
new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
ConstantInt::get(IntptrTy, Mapping.Offset),
kAsanMappingOffsetName);
IRB.CreateLoad(asan_mapping_offset, true);
GlobalValue *asan_mapping_scale =
new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
ConstantInt::get(IntptrTy, Mapping.Scale),
kAsanMappingScaleName);
IRB.CreateLoad(asan_mapping_scale, true);
}
bool AddressSanitizer::doInitialization(Module &M) {
TD = getAnalysisIfAvailable<DataLayout>();
if (!TD)
return false;
BL.reset(SpecialCaseList::createOrDie(BlacklistFile));
DynamicallyInitializedGlobals.Init(M);
C = &(M.getContext());
LongSize = TD->getPointerSizeInBits();
IntptrTy = Type::getIntNTy(*C, LongSize);
AsanCtorFunction = Function::Create(
FunctionType::get(Type::getVoidTy(*C), false),
GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
AsanInitFunction = checkInterfaceFunction(
M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
AsanInitFunction->setLinkage(Function::ExternalLinkage);
IRB.CreateCall(AsanInitFunction);
Mapping = getShadowMapping(M, LongSize);
emitShadowMapping(M, IRB);
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
return true;
}
bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
if (F.getName().find(" load]") != std::string::npos) {
IRBuilder<> IRB(F.begin()->begin());
IRB.CreateCall(AsanInitFunction);
return true;
}
return false;
}
void AddressSanitizer::InjectCoverageAtBlock(Function &F, BasicBlock &BB) {
BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
for (; IP != BE; ++IP) {
AllocaInst *AI = dyn_cast<AllocaInst>(IP);
if (!AI || !AI->isStaticAlloca())
break;
}
IRBuilder<> IRB(IP);
Type *Int8Ty = IRB.getInt8Ty();
GlobalVariable *Guard = new GlobalVariable(
*F.getParent(), Int8Ty, false, GlobalValue::PrivateLinkage,
Constant::getNullValue(Int8Ty), "__asan_gen_cov_" + F.getName());
LoadInst *Load = IRB.CreateLoad(Guard);
Load->setAtomic(Monotonic);
Load->setAlignment(1);
Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load);
Instruction *Ins = SplitBlockAndInsertIfThen(
Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
IRB.SetInsertPoint(Ins);
Instruction *Call = IRB.CreateCall(AsanCovFunction);
Call->setDebugLoc(IP->getDebugLoc());
StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
Store->setAtomic(Monotonic);
Store->setAlignment(1);
}
bool AddressSanitizer::InjectCoverage(Function &F,
const ArrayRef<BasicBlock *> AllBlocks) {
if (!ClCoverage) return false;
if (ClCoverage == 1) {
InjectCoverageAtBlock(F, F.getEntryBlock());
} else {
for (size_t i = 0, n = AllBlocks.size(); i < n; i++)
InjectCoverageAtBlock(F, *AllBlocks[i]);
}
return true;
}
bool AddressSanitizer::runOnFunction(Function &F) {
if (BL->isIn(F)) return false;
if (&F == AsanCtorFunction) return false;
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
initializeCallbacks(*F.getParent());
maybeInsertAsanInitAtFunctionEntry(F);
if (!F.hasFnAttribute(Attribute::SanitizeAddress))
return false;
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
return false;
SmallSet<Value*, 16> TempsToInstrument;
SmallVector<Instruction*, 16> ToInstrument;
SmallVector<Instruction*, 8> NoReturnCalls;
SmallVector<BasicBlock*, 16> AllBlocks;
int NumAllocas = 0;
bool IsWrite;
for (Function::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI) {
AllBlocks.push_back(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; }
} else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
} else {
if (isa<AllocaInst>(BI))
NumAllocas++;
CallSite CS(BI);
if (CS) {
TempsToInstrument.clear();
if (CS.doesNotReturn())
NoReturnCalls.push_back(CS.getInstruction());
}
continue;
}
ToInstrument.push_back(BI);
NumInsnsPerBB++;
if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
break;
}
}
Function *UninstrumentedDuplicate = 0;
bool LikelyToInstrument =
!NoReturnCalls.empty() || !ToInstrument.empty() || (NumAllocas > 0);
if (ClKeepUninstrumented && LikelyToInstrument) {
ValueToValueMapTy VMap;
UninstrumentedDuplicate = CloneFunction(&F, VMap, false);
UninstrumentedDuplicate->removeFnAttr(Attribute::SanitizeAddress);
UninstrumentedDuplicate->setName("NOASAN_" + F.getName());
F.getParent()->getFunctionList().push_back(UninstrumentedDuplicate);
}
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++;
}
FunctionStackPoisoner FSP(F, *this);
bool ChangedStack = FSP.runOnFunction();
for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
Instruction *CI = NoReturnCalls[i];
IRBuilder<> IRB(CI);
IRB.CreateCall(AsanHandleNoReturnFunc);
}
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
if (InjectCoverage(F, AllBlocks))
res = true;
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
if (ClKeepUninstrumented) {
if (!res) {
if (UninstrumentedDuplicate)
UninstrumentedDuplicate->eraseFromParent();
} else {
assert(UninstrumentedDuplicate);
UninstrumentedDuplicate->setSection("NOASAN");
assert(!F.hasSection());
F.setSection("ASAN");
}
}
return res;
}
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;
return true;
}
void FunctionStackPoisoner::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) {
std::string Suffix = itostr(i);
AsanStackMallocFunc[i] = checkInterfaceFunction(
M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
IntptrTy, IntptrTy, NULL));
AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
IntptrTy, IntptrTy, NULL));
}
AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
}
void
FunctionStackPoisoner::poisonRedZones(const ArrayRef<uint8_t> ShadowBytes,
IRBuilder<> &IRB, Value *ShadowBase,
bool DoPoison) {
size_t n = ShadowBytes.size();
size_t i = 0;
for (size_t LargeStoreSizeInBytes = ASan.LongSize / 8;
LargeStoreSizeInBytes != 0; LargeStoreSizeInBytes /= 2) {
for (; i + LargeStoreSizeInBytes - 1 < n; i += LargeStoreSizeInBytes) {
uint64_t Val = 0;
for (size_t j = 0; j < LargeStoreSizeInBytes; j++) {
if (ASan.TD->isLittleEndian())
Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
else
Val = (Val << 8) | ShadowBytes[i + j];
}
if (!Val) continue;
Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
Type *StoreTy = Type::getIntNTy(*C, LargeStoreSizeInBytes * 8);
Value *Poison = ConstantInt::get(StoreTy, DoPoison ? Val : 0);
IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, StoreTy->getPointerTo()));
}
}
}
static int StackMallocSizeClass(uint64_t LocalStackSize) {
assert(LocalStackSize <= kMaxStackMallocSize);
uint64_t MaxSize = kMinStackMallocSize;
for (int i = 0; ; i++, MaxSize *= 2)
if (LocalStackSize <= MaxSize)
return i;
llvm_unreachable("impossible LocalStackSize");
}
void FunctionStackPoisoner::SetShadowToStackAfterReturnInlined(
IRBuilder<> &IRB, Value *ShadowBase, int Size) {
assert(!(Size % 8));
assert(kAsanStackAfterReturnMagic == 0xf5);
for (int i = 0; i < Size; i += 8) {
Value *p = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
IRB.CreateStore(ConstantInt::get(IRB.getInt64Ty(), 0xf5f5f5f5f5f5f5f5ULL),
IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo()));
}
}
void FunctionStackPoisoner::poisonStack() {
int StackMallocIdx = -1;
assert(AllocaVec.size() > 0);
Instruction *InsBefore = AllocaVec[0];
IRBuilder<> IRB(InsBefore);
SmallVector<ASanStackVariableDescription, 16> SVD;
SVD.reserve(AllocaVec.size());
for (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
AllocaInst *AI = AllocaVec[i];
ASanStackVariableDescription D = { AI->getName().data(),
getAllocaSizeInBytes(AI),
AI->getAlignment(), AI, 0};
SVD.push_back(D);
}
size_t MinHeaderSize = ASan.LongSize / 2;
ASanStackFrameLayout L;
ComputeASanStackFrameLayout(SVD, 1UL << Mapping.Scale, MinHeaderSize, &L);
DEBUG(dbgs() << L.DescriptionString << " --- " << L.FrameSize << "\n");
uint64_t LocalStackSize = L.FrameSize;
bool DoStackMalloc =
ASan.CheckUseAfterReturn && LocalStackSize <= kMaxStackMallocSize;
Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
AllocaInst *MyAlloca =
new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
assert((ClRealignStack & (ClRealignStack - 1)) == 0);
size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
MyAlloca->setAlignment(FrameAlignment);
assert(MyAlloca->isStaticAlloca());
Value *OrigStackBase = IRB.CreatePointerCast(MyAlloca, IntptrTy);
Value *LocalStackBase = OrigStackBase;
if (DoStackMalloc) {
StackMallocIdx = StackMallocSizeClass(LocalStackSize);
assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
Constant *OptionDetectUAR = F.getParent()->getOrInsertGlobal(
kAsanOptionDetectUAR, IRB.getInt32Ty());
Value *Cmp = IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR),
Constant::getNullValue(IRB.getInt32Ty()));
Instruction *Term = SplitBlockAndInsertIfThen(Cmp, InsBefore, false);
BasicBlock *CmpBlock = cast<Instruction>(Cmp)->getParent();
IRBuilder<> IRBIf(Term);
LocalStackBase = IRBIf.CreateCall2(
AsanStackMallocFunc[StackMallocIdx],
ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
BasicBlock *SetBlock = cast<Instruction>(LocalStackBase)->getParent();
IRB.SetInsertPoint(InsBefore);
PHINode *Phi = IRB.CreatePHI(IntptrTy, 2);
Phi->addIncoming(OrigStackBase, CmpBlock);
Phi->addIncoming(LocalStackBase, SetBlock);
LocalStackBase = Phi;
}
bool HavePoisonedAllocas = false;
for (size_t i = 0, n = AllocaPoisonCallVec.size(); i < n; i++) {
const AllocaPoisonCall &APC = AllocaPoisonCallVec[i];
assert(APC.InsBefore);
assert(APC.AI);
IRBuilder<> IRB(APC.InsBefore);
poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
HavePoisonedAllocas |= APC.DoPoison;
}
for (size_t i = 0, n = SVD.size(); i < n; i++) {
AllocaInst *AI = SVD[i].AI;
Value *NewAllocaPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(LocalStackBase,
ConstantInt::get(IntptrTy, SVD[i].Offset)),
AI->getType());
replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
AI->replaceAllUsesWith(NewAllocaPtr);
}
Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
IRB.CreateStore(ConstantInt::get(IntptrTy, kCurrentStackFrameMagic),
BasePlus0);
Value *BasePlus1 = IRB.CreateIntToPtr(
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)),
IntptrPtrTy);
GlobalVariable *StackDescriptionGlobal =
createPrivateGlobalForString(*F.getParent(), L.DescriptionString,
true);
Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal,
IntptrTy);
IRB.CreateStore(Description, BasePlus1);
Value *BasePlus2 = IRB.CreateIntToPtr(
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy,
2 * ASan.LongSize/8)),
IntptrPtrTy);
IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2);
Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true);
for (size_t i = 0, n = RetVec.size(); i < n; i++) {
Instruction *Ret = RetVec[i];
IRBuilder<> IRBRet(Ret);
IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
BasePlus0);
if (DoStackMalloc) {
assert(StackMallocIdx >= 0);
Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase);
TerminatorInst *ThenTerm, *ElseTerm;
SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
IRBuilder<> IRBPoison(ThenTerm);
if (StackMallocIdx <= 4) {
int ClassSize = kMinStackMallocSize << StackMallocIdx;
SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase,
ClassSize >> Mapping.Scale);
Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
LocalStackBase,
ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
Value *SavedFlagPtr = IRBPoison.CreateLoad(
IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
IRBPoison.CreateStore(
Constant::getNullValue(IRBPoison.getInt8Ty()),
IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
} else {
IRBPoison.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase,
ConstantInt::get(IntptrTy, LocalStackSize),
OrigStackBase);
}
IRBuilder<> IRBElse(ElseTerm);
poisonRedZones(L.ShadowBytes, IRBElse, ShadowBase, false);
} else if (HavePoisonedAllocas) {
assert(LocalStackBase == OrigStackBase);
poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false);
} else {
poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false);
}
}
for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
AllocaVec[i]->eraseFromParent();
}
void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
IRBuilder<> &IRB, bool DoPoison) {
Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy);
Value *SizeArg = ConstantInt::get(IntptrTy, Size);
IRB.CreateCall2(DoPoison ? AsanPoisonStackMemoryFunc
: AsanUnpoisonStackMemoryFunc,
AddrArg, SizeArg);
}
AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
return isInterestingAlloca(*AI) ? AI : 0;
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
if (I != AllocaForValue.end())
return I->second;
AllocaForValue[V] = 0;
AllocaInst *Res = 0;
if (CastInst *CI = dyn_cast<CastInst>(V))
Res = findAllocaForValue(CI->getOperand(0));
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *IncValue = PN->getIncomingValue(i);
if (IncValue == PN) continue;
AllocaInst *IncValueAI = findAllocaForValue(IncValue);
if (IncValueAI == 0 || (Res != 0 && IncValueAI != Res))
return 0;
Res = IncValueAI;
}
}
if (Res != 0)
AllocaForValue[V] = Res;
return Res;
}