#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
+#include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
+#include "llvm/MC/MCSectionMachO.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
+#include "llvm/Support/SwapByteOrder.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.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/PromoteMemToReg.h"
#include <algorithm>
#include <string>
#include <system_error>
static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
-static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 36;
+static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
+static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
+static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
-static const size_t kMinStackMallocSize = 1 << 6; // 64B
+static const size_t kMinStackMallocSize = 1 << 6; // 64B
static const size_t kMaxStackMallocSize = 1 << 16; // 64K
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 uint64_t kAsanCtorAndDtorPriority = 1;
+static const uint64_t kAsanCtorAndDtorPriority = 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_v4";
+static const char *const kAsanInitName = "__asan_init_v5";
static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp";
static const char *const kAsanPtrSub = "__sanitizer_ptr_sub";
static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
-static const int kMaxAsanStackMallocSizeClass = 10;
+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 kAsanOptionDetectUAR =
"__asan_option_detect_stack_use_after_return";
-#ifndef NDEBUG
-static const int kAsanStackAfterReturnMagic = 0xf5;
-#endif
-
// Accesses sizes are powers of two: 1, 2, 4, 8, 16.
static const size_t kNumberOfAccessSizes = 5;
+static const unsigned kAllocaRzSize = 32;
+static const unsigned kAsanAllocaLeftMagic = 0xcacacacaU;
+static const unsigned kAsanAllocaRightMagic = 0xcbcbcbcbU;
+static const unsigned kAsanAllocaPartialVal1 = 0xcbcbcb00U;
+static const unsigned kAsanAllocaPartialVal2 = 0x000000cbU;
+
// 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));
+ 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);
+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));
+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(true));
+ cl::desc("Check return-after-free"),
+ cl::Hidden, cl::init(true));
// 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));
+ 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(true));
-static cl::opt<bool> ClInvalidPointerPairs("asan-detect-invalid-pointer-pair",
- cl::desc("Instrument <, <=, >, >=, - with pointer operands"),
- cl::Hidden, cl::init(false));
-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));
+ cl::desc("Handle C++ initializer order"),
+ cl::Hidden, cl::init(true));
+static cl::opt<bool> ClInvalidPointerPairs(
+ "asan-detect-invalid-pointer-pair",
+ cl::desc("Instrument <, <=, >, >=, - with pointer operands"), cl::Hidden,
+ cl::init(false));
+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<int> ClInstrumentationWithCallsThreshold(
"asan-instrumentation-with-call-threshold",
- cl::desc("If the function being instrumented contains more than "
- "this number of memory accesses, use callbacks instead of "
- "inline checks (-1 means never use callbacks)."),
- cl::Hidden, cl::init(7000));
+ cl::desc(
+ "If the function being instrumented contains more than "
+ "this number of memory accesses, use callbacks instead of "
+ "inline checks (-1 means never use callbacks)."),
+ cl::Hidden, cl::init(7000));
static cl::opt<std::string> ClMemoryAccessCallbackPrefix(
- "asan-memory-access-callback-prefix",
- cl::desc("Prefix for memory access callbacks"), cl::Hidden,
- cl::init("__asan_"));
-
-// This is an experimental feature that will allow to choose between
-// instrumented and non-instrumented code at link-time.
-// If this option is on, just before instrumenting a function we create its
-// clone; if the function is not changed by asan the clone is deleted.
-// If we end up with a clone, we put the instrumented function into a section
-// called "ASAN" and the uninstrumented function into a section called "NOASAN".
-//
-// This is still a prototype, we need to figure out a way to keep two copies of
-// a function so that the linker can easily choose one of them.
-static cl::opt<bool> ClKeepUninstrumented("asan-keep-uninstrumented-functions",
- cl::desc("Keep uninstrumented copies of functions"),
- cl::Hidden, cl::init(false));
+ "asan-memory-access-callback-prefix",
+ cl::desc("Prefix for memory access callbacks"), cl::Hidden,
+ cl::init("__asan_"));
+static cl::opt<bool> ClInstrumentAllocas("asan-instrument-allocas",
+ cl::desc("instrument dynamic allocas"),
+ cl::Hidden, cl::init(false));
+static cl::opt<bool> ClSkipPromotableAllocas(
+ "asan-skip-promotable-allocas",
+ cl::desc("Do not instrument promotable allocas"), cl::Hidden,
+ cl::init(true));
// 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));
+ cl::desc("scale of asan shadow mapping"),
+ cl::Hidden, cl::init(0));
// 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> 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));
+ cl::desc("Don't instrument scalar globals"),
+ cl::Hidden, cl::init(true));
+static cl::opt<bool> ClOptStack(
+ "asan-opt-stack", cl::desc("Don't instrument scalar stack variables"),
+ cl::Hidden, cl::init(false));
+
+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<bool> ClDynamicAllocaStack(
+ "asan-stack-dynamic-alloca",
+ cl::desc("Use dynamic alloca to represent stack variables"), cl::Hidden,
+ cl::init(true));
+
+static cl::opt<uint32_t> ClForceExperiment(
+ "asan-force-experiment",
+ cl::desc("Force optimization experiment (for testing)"), cl::Hidden,
+ cl::init(0));
// 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<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"),
STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
-STATISTIC(NumOptimizedAccessesToGlobalArray,
- "Number of optimized accesses to global arrays");
+STATISTIC(NumInstrumentedDynamicAllocas,
+ "Number of instrumented dynamic allocas");
STATISTIC(NumOptimizedAccessesToGlobalVar,
"Number of optimized accesses to global vars");
+STATISTIC(NumOptimizedAccessesToStackVar,
+ "Number of optimized accesses to stack vars");
namespace {
/// Frontend-provided metadata for source location.
assert(MDN->getNumOperands() == 3);
MDString *MDFilename = cast<MDString>(MDN->getOperand(0));
Filename = MDFilename->getString();
- LineNo = cast<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
- ColumnNo = cast<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
+ LineNo =
+ mdconst::extract<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
+ ColumnNo =
+ mdconst::extract<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
}
};
class GlobalsMetadata {
public:
struct Entry {
- Entry()
- : SourceLoc(), Name(), IsDynInit(false),
- IsBlacklisted(false) {}
+ Entry() : SourceLoc(), Name(), IsDynInit(false), IsBlacklisted(false) {}
LocationMetadata SourceLoc;
StringRef Name;
bool IsDynInit;
GlobalsMetadata() : inited_(false) {}
- void init(Module& M) {
+ void init(Module &M) {
assert(!inited_);
inited_ = true;
NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
- if (!Globals)
- return;
+ if (!Globals) return;
for (auto MDN : Globals->operands()) {
// Metadata node contains the global and the fields of "Entry".
assert(MDN->getNumOperands() == 5);
- Value *V = MDN->getOperand(0);
+ auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
// The optimizer may optimize away a global entirely.
- if (!V)
- continue;
- GlobalVariable *GV = cast<GlobalVariable>(V);
+ if (!GV) continue;
// We can already have an entry for GV if it was merged with another
// global.
Entry &E = Entries[GV];
- if (Value *Loc = MDN->getOperand(1))
- E.SourceLoc.parse(cast<MDNode>(Loc));
- if (Value *Name = MDN->getOperand(2)) {
- MDString *MDName = cast<MDString>(Name);
- E.Name = MDName->getString();
- }
- ConstantInt *IsDynInit = cast<ConstantInt>(MDN->getOperand(3));
+ if (auto *Loc = cast_or_null<MDNode>(MDN->getOperand(1)))
+ E.SourceLoc.parse(Loc);
+ if (auto *Name = cast_or_null<MDString>(MDN->getOperand(2)))
+ E.Name = Name->getString();
+ ConstantInt *IsDynInit =
+ mdconst::extract<ConstantInt>(MDN->getOperand(3));
E.IsDynInit |= IsDynInit->isOne();
- ConstantInt *IsBlacklisted = cast<ConstantInt>(MDN->getOperand(4));
+ ConstantInt *IsBlacklisted =
+ mdconst::extract<ConstantInt>(MDN->getOperand(4));
E.IsBlacklisted |= IsBlacklisted->isOne();
}
}
private:
bool inited_;
- DenseMap<GlobalVariable*, Entry> Entries;
+ DenseMap<GlobalVariable *, Entry> Entries;
};
/// This struct defines the shadow mapping using the rule:
bool OrShadowOffset;
};
-static ShadowMapping getShadowMapping(const Module &M, int LongSize) {
- llvm::Triple TargetTriple(M.getTargetTriple());
+static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize) {
bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
bool IsIOS = TargetTriple.isiOS();
- bool IsFreeBSD = TargetTriple.getOS() == llvm::Triple::FreeBSD;
- bool IsLinux = TargetTriple.getOS() == llvm::Triple::Linux;
+ bool IsFreeBSD = TargetTriple.isOSFreeBSD();
+ bool IsLinux = TargetTriple.isOSLinux();
bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
TargetTriple.getArch() == llvm::Triple::ppc64le;
bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
TargetTriple.getArch() == llvm::Triple::mipsel;
bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
TargetTriple.getArch() == llvm::Triple::mips64el;
+ bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64;
+ bool IsWindows = TargetTriple.isOSWindows();
ShadowMapping Mapping;
Mapping.Offset = kFreeBSD_ShadowOffset32;
else if (IsIOS)
Mapping.Offset = kIOSShadowOffset32;
+ else if (IsWindows)
+ Mapping.Offset = kWindowsShadowOffset32;
else
Mapping.Offset = kDefaultShadowOffset32;
} else { // LongSize == 64
Mapping.Offset = kSmallX86_64ShadowOffset;
else if (IsMIPS64)
Mapping.Offset = kMIPS64_ShadowOffset64;
+ else if (IsAArch64)
+ Mapping.Offset = kAArch64_ShadowOffset64;
else
Mapping.Offset = kDefaultShadowOffset64;
}
/// AddressSanitizer: instrument the code in module to find memory bugs.
struct AddressSanitizer : public FunctionPass {
- AddressSanitizer() : FunctionPass(ID) {}
+ AddressSanitizer() : FunctionPass(ID) {
+ initializeAddressSanitizerPass(*PassRegistry::getPassRegistry());
+ }
const char *getPassName() const override {
return "AddressSanitizerFunctionPass";
}
- void instrumentMop(Instruction *I, bool UseCalls);
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<DominatorTreeWrapperPass>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
+ }
+ uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
+ Type *Ty = AI->getAllocatedType();
+ uint64_t SizeInBytes =
+ AI->getModule()->getDataLayout().getTypeAllocSize(Ty);
+ return SizeInBytes;
+ }
+ /// Check if we want (and can) handle this alloca.
+ bool isInterestingAlloca(AllocaInst &AI) const;
+ /// If it is an interesting memory access, return the PointerOperand
+ /// and set IsWrite/Alignment. Otherwise return nullptr.
+ Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
+ uint64_t *TypeSize,
+ unsigned *Alignment) const;
+ void instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis, Instruction *I,
+ bool UseCalls, const DataLayout &DL);
void instrumentPointerComparisonOrSubtraction(Instruction *I);
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
Value *Addr, uint32_t TypeSize, bool IsWrite,
- Value *SizeArgument, bool UseCalls);
+ Value *SizeArgument, bool UseCalls, uint32_t Exp);
+ void instrumentUnusualSizeOrAlignment(Instruction *I, Value *Addr,
+ uint32_t TypeSize, bool IsWrite,
+ Value *SizeArgument, bool UseCalls,
+ uint32_t Exp);
Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
Value *ShadowValue, uint32_t TypeSize);
Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
bool IsWrite, size_t AccessSizeIndex,
- Value *SizeArgument);
+ Value *SizeArgument, uint32_t Exp);
void instrumentMemIntrinsic(MemIntrinsic *MI);
Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
bool runOnFunction(Function &F) override;
bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid
+ DominatorTree &getDominatorTree() const { return *DT; }
+
private:
void initializeCallbacks(Module &M);
bool LooksLikeCodeInBug11395(Instruction *I);
bool GlobalIsLinkerInitialized(GlobalVariable *G);
+ bool isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis, Value *Addr,
+ uint64_t TypeSize) const;
LLVMContext *C;
- const DataLayout *DL;
+ Triple TargetTriple;
int LongSize;
Type *IntptrTy;
ShadowMapping Mapping;
+ DominatorTree *DT;
Function *AsanCtorFunction;
Function *AsanInitFunction;
Function *AsanHandleNoReturnFunc;
Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
- // This array is indexed by AccessIsWrite and log2(AccessSize).
- Function *AsanErrorCallback[2][kNumberOfAccessSizes];
- Function *AsanMemoryAccessCallback[2][kNumberOfAccessSizes];
- // This array is indexed by AccessIsWrite.
- Function *AsanErrorCallbackSized[2],
- *AsanMemoryAccessCallbackSized[2];
+ // This array is indexed by AccessIsWrite, Experiment and log2(AccessSize).
+ Function *AsanErrorCallback[2][2][kNumberOfAccessSizes];
+ Function *AsanMemoryAccessCallback[2][2][kNumberOfAccessSizes];
+ // This array is indexed by AccessIsWrite and Experiment.
+ Function *AsanErrorCallbackSized[2][2];
+ Function *AsanMemoryAccessCallbackSized[2][2];
Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
InlineAsm *EmptyAsm;
GlobalsMetadata GlobalsMD;
AddressSanitizerModule() : ModulePass(ID) {}
bool runOnModule(Module &M) override;
static char ID; // Pass identification, replacement for typeid
- const char *getPassName() const override {
- return "AddressSanitizerModule";
- }
+ const char *getPassName() const override { return "AddressSanitizerModule"; }
private:
void initializeCallbacks(Module &M);
GlobalsMetadata GlobalsMD;
Type *IntptrTy;
LLVMContext *C;
- const DataLayout *DL;
+ Triple TargetTriple;
ShadowMapping Mapping;
Function *AsanPoisonGlobals;
Function *AsanUnpoisonGlobals;
Type *IntptrPtrTy;
ShadowMapping Mapping;
- SmallVector<AllocaInst*, 16> AllocaVec;
- SmallVector<Instruction*, 8> RetVec;
+ SmallVector<AllocaInst *, 16> AllocaVec;
+ SmallVector<Instruction *, 8> RetVec;
unsigned StackAlignment;
Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
- *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
+ *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
// Stores a place and arguments of poisoning/unpoisoning call for alloca.
};
SmallVector<AllocaPoisonCall, 8> AllocaPoisonCallVec;
+ // Stores left and right redzone shadow addresses for dynamic alloca
+ // and pointer to alloca instruction itself.
+ // LeftRzAddr is a shadow address for alloca left redzone.
+ // RightRzAddr is a shadow address for alloca right redzone.
+ struct DynamicAllocaCall {
+ AllocaInst *AI;
+ Value *LeftRzAddr;
+ Value *RightRzAddr;
+ bool Poison;
+ explicit DynamicAllocaCall(AllocaInst *AI, Value *LeftRzAddr = nullptr,
+ Value *RightRzAddr = nullptr)
+ : AI(AI),
+ LeftRzAddr(LeftRzAddr),
+ RightRzAddr(RightRzAddr),
+ Poison(true) {}
+ };
+ SmallVector<DynamicAllocaCall, 1> DynamicAllocaVec;
+
// Maps Value to an AllocaInst from which the Value is originated.
- typedef DenseMap<Value*, AllocaInst*> AllocaForValueMapTy;
+ typedef DenseMap<Value *, AllocaInst *> AllocaForValueMapTy;
AllocaForValueMapTy AllocaForValue;
+ bool HasNonEmptyInlineAsm;
+ std::unique_ptr<CallInst> EmptyInlineAsm;
+
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
- : F(F), ASan(ASan), DIB(*F.getParent()), C(ASan.C),
- IntptrTy(ASan.IntptrTy), IntptrPtrTy(PointerType::get(IntptrTy, 0)),
+ : F(F),
+ ASan(ASan),
+ DIB(*F.getParent(), /*AllowUnresolved*/ false),
+ C(ASan.C),
+ IntptrTy(ASan.IntptrTy),
+ IntptrPtrTy(PointerType::get(IntptrTy, 0)),
Mapping(ASan.Mapping),
- StackAlignment(1 << Mapping.Scale) {}
+ StackAlignment(1 << Mapping.Scale),
+ HasNonEmptyInlineAsm(false),
+ EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
bool runOnFunction() {
if (!ClStack) return false;
// Collect alloca, ret, lifetime instructions etc.
- for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
- visit(*BB);
+ for (BasicBlock *BB : depth_first(&F.getEntryBlock())) visit(*BB);
- if (AllocaVec.empty()) return false;
+ if (AllocaVec.empty() && DynamicAllocaVec.empty()) return false;
initializeCallbacks(*F.getParent());
return true;
}
- // Finds all static Alloca instructions and puts
+ // Finds all Alloca instructions and puts
// poisoned red zones around all of them.
// Then unpoison everything back before the function returns.
void poisonStack();
// ----------------------- Visitors.
/// \brief Collect all Ret instructions.
- void visitReturnInst(ReturnInst &RI) {
- RetVec.push_back(&RI);
+ void visitReturnInst(ReturnInst &RI) { RetVec.push_back(&RI); }
+
+ // Unpoison dynamic allocas redzones.
+ void unpoisonDynamicAlloca(DynamicAllocaCall &AllocaCall) {
+ if (!AllocaCall.Poison) return;
+ for (auto Ret : RetVec) {
+ IRBuilder<> IRBRet(Ret);
+ PointerType *Int32PtrTy = PointerType::getUnqual(IRBRet.getInt32Ty());
+ Value *Zero = Constant::getNullValue(IRBRet.getInt32Ty());
+ Value *PartialRzAddr = IRBRet.CreateSub(AllocaCall.RightRzAddr,
+ ConstantInt::get(IntptrTy, 4));
+ IRBRet.CreateStore(
+ Zero, IRBRet.CreateIntToPtr(AllocaCall.LeftRzAddr, Int32PtrTy));
+ IRBRet.CreateStore(Zero,
+ IRBRet.CreateIntToPtr(PartialRzAddr, Int32PtrTy));
+ IRBRet.CreateStore(
+ Zero, IRBRet.CreateIntToPtr(AllocaCall.RightRzAddr, Int32PtrTy));
+ }
}
+ // Right shift for BigEndian and left shift for LittleEndian.
+ Value *shiftAllocaMagic(Value *Val, IRBuilder<> &IRB, Value *Shift) {
+ auto &DL = F.getParent()->getDataLayout();
+ return DL.isLittleEndian() ? IRB.CreateShl(Val, Shift)
+ : IRB.CreateLShr(Val, Shift);
+ }
+
+ // Compute PartialRzMagic for dynamic alloca call. Since we don't know the
+ // size of requested memory until runtime, we should compute it dynamically.
+ // If PartialSize is 0, PartialRzMagic would contain kAsanAllocaRightMagic,
+ // otherwise it would contain the value that we will use to poison the
+ // partial redzone for alloca call.
+ Value *computePartialRzMagic(Value *PartialSize, IRBuilder<> &IRB);
+
+ // Deploy and poison redzones around dynamic alloca call. To do this, we
+ // should replace this call with another one with changed parameters and
+ // replace all its uses with new address, so
+ // addr = alloca type, old_size, align
+ // is replaced by
+ // new_size = (old_size + additional_size) * sizeof(type)
+ // tmp = alloca i8, new_size, max(align, 32)
+ // addr = tmp + 32 (first 32 bytes are for the left redzone).
+ // Additional_size is added to make new memory allocation contain not only
+ // requested memory, but also left, partial and right redzones.
+ // After that, we should poison redzones:
+ // (1) Left redzone with kAsanAllocaLeftMagic.
+ // (2) Partial redzone with the value, computed in runtime by
+ // computePartialRzMagic function.
+ // (3) Right redzone with kAsanAllocaRightMagic.
+ void handleDynamicAllocaCall(DynamicAllocaCall &AllocaCall);
+
/// \brief Collect Alloca instructions we want (and can) handle.
void visitAllocaInst(AllocaInst &AI) {
- if (!isInterestingAlloca(AI)) return;
+ if (!ASan.isInterestingAlloca(AI)) return;
StackAlignment = std::max(StackAlignment, AI.getAlignment());
- AllocaVec.push_back(&AI);
+ if (isDynamicAlloca(AI))
+ DynamicAllocaVec.push_back(DynamicAllocaCall(&AI));
+ else
+ AllocaVec.push_back(&AI);
}
/// \brief Collect lifetime intrinsic calls to check for use-after-scope
void visitIntrinsicInst(IntrinsicInst &II) {
if (!ClCheckLifetime) return;
Intrinsic::ID ID = II.getIntrinsicID();
- if (ID != Intrinsic::lifetime_start &&
- ID != Intrinsic::lifetime_end)
+ if (ID != Intrinsic::lifetime_start && ID != Intrinsic::lifetime_end)
return;
// Found lifetime intrinsic, add ASan instrumentation if necessary.
ConstantInt *Size = dyn_cast<ConstantInt>(II.getArgOperand(0));
AllocaPoisonCallVec.push_back(APC);
}
+ void visitCallInst(CallInst &CI) {
+ HasNonEmptyInlineAsm |=
+ CI.isInlineAsm() && !CI.isIdenticalTo(EmptyInlineAsm.get());
+ }
+
// ---------------------- Helpers.
void initializeCallbacks(Module &M);
- // Check if we want (and can) handle this alloca.
- bool isInterestingAlloca(AllocaInst &AI) const {
- return (!AI.isArrayAllocation() && AI.isStaticAlloca() &&
- AI.getAllocatedType()->isSized() &&
- // alloca() may be called with 0 size, ignore it.
- getAllocaSizeInBytes(&AI) > 0);
+ bool doesDominateAllExits(const Instruction *I) const {
+ for (auto Ret : RetVec) {
+ if (!ASan.getDominatorTree().dominates(I, Ret)) return false;
+ }
+ return true;
}
- uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
- Type *Ty = AI->getAllocatedType();
- uint64_t SizeInBytes = ASan.DL->getTypeAllocSize(Ty);
- return SizeInBytes;
+ bool isDynamicAlloca(AllocaInst &AI) const {
+ return AI.isArrayAllocation() || !AI.isStaticAlloca();
}
/// Finds alloca where the value comes from.
AllocaInst *findAllocaForValue(Value *V);
void SetShadowToStackAfterReturnInlined(IRBuilder<> &IRB, Value *ShadowBase,
int Size);
+ Value *createAllocaForLayout(IRBuilder<> &IRB, const ASanStackFrameLayout &L,
+ bool Dynamic);
+ PHINode *createPHI(IRBuilder<> &IRB, Value *Cond, Value *ValueIfTrue,
+ Instruction *ThenTerm, Value *ValueIfFalse);
};
} // namespace
char AddressSanitizer::ID = 0;
-INITIALIZE_PASS(AddressSanitizer, "asan",
- "AddressSanitizer: detects use-after-free and out-of-bounds bugs.",
- false, false)
+INITIALIZE_PASS_BEGIN(
+ AddressSanitizer, "asan",
+ "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
+ false)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_END(
+ AddressSanitizer, "asan",
+ "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
+ false)
FunctionPass *llvm::createAddressSanitizerFunctionPass() {
return new AddressSanitizer();
}
char AddressSanitizerModule::ID = 0;
-INITIALIZE_PASS(AddressSanitizerModule, "asan-module",
+INITIALIZE_PASS(
+ AddressSanitizerModule, "asan-module",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
- "ModulePass", false, false)
+ "ModulePass",
+ false, false)
ModulePass *llvm::createAddressSanitizerModulePass() {
return new AddressSanitizerModule();
}
}
// \brief Create a constant for Str so that we can pass it to the run-time lib.
-static GlobalVariable *createPrivateGlobalForString(
- Module &M, StringRef Str, bool AllowMerging) {
+static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
+ bool AllowMerging) {
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
// We use private linkage for module-local strings. If they can be merged
// with another one, we set the unnamed_addr attribute.
GlobalVariable *GV =
new GlobalVariable(M, StrConst->getType(), true,
GlobalValue::PrivateLinkage, StrConst, kAsanGenPrefix);
- if (AllowMerging)
- GV->setUnnamedAddr(true);
+ if (AllowMerging) GV->setUnnamedAddr(true);
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
return GV;
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
// Shadow >> scale
Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
- if (Mapping.Offset == 0)
- return Shadow;
+ if (Mapping.Offset == 0) return Shadow;
// (Shadow >> scale) | offset
if (Mapping.OrShadowOffset)
return IRB.CreateOr(Shadow, ConstantInt::get(IntptrTy, Mapping.Offset));
MI->eraseFromParent();
}
-// If I is an interesting memory access, return the PointerOperand
-// and set IsWrite/Alignment. Otherwise return nullptr.
-static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
- unsigned *Alignment) {
+/// Check if we want (and can) handle this alloca.
+bool AddressSanitizer::isInterestingAlloca(AllocaInst &AI) const {
+ return (AI.getAllocatedType()->isSized() &&
+ // alloca() may be called with 0 size, ignore it.
+ getAllocaSizeInBytes(&AI) > 0 &&
+ // We are only interested in allocas not promotable to registers.
+ // Promotable allocas are common under -O0.
+ (!ClSkipPromotableAllocas || !isAllocaPromotable(&AI)));
+}
+
+/// If I is an interesting memory access, return the PointerOperand
+/// and set IsWrite/Alignment. Otherwise return nullptr.
+Value *AddressSanitizer::isInterestingMemoryAccess(Instruction *I,
+ bool *IsWrite,
+ uint64_t *TypeSize,
+ unsigned *Alignment) const {
// Skip memory accesses inserted by another instrumentation.
- if (I->getMetadata("nosanitize"))
- return nullptr;
+ if (I->getMetadata("nosanitize")) return nullptr;
+
+ Value *PtrOperand = nullptr;
+ const DataLayout &DL = I->getModule()->getDataLayout();
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (!ClInstrumentReads) return nullptr;
*IsWrite = false;
+ *TypeSize = DL.getTypeStoreSizeInBits(LI->getType());
*Alignment = LI->getAlignment();
- return LI->getPointerOperand();
- }
- if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
+ PtrOperand = LI->getPointerOperand();
+ } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
if (!ClInstrumentWrites) return nullptr;
*IsWrite = true;
+ *TypeSize = DL.getTypeStoreSizeInBits(SI->getValueOperand()->getType());
*Alignment = SI->getAlignment();
- return SI->getPointerOperand();
- }
- if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
+ PtrOperand = SI->getPointerOperand();
+ } else if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
if (!ClInstrumentAtomics) return nullptr;
*IsWrite = true;
+ *TypeSize = DL.getTypeStoreSizeInBits(RMW->getValOperand()->getType());
*Alignment = 0;
- return RMW->getPointerOperand();
- }
- if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
+ PtrOperand = RMW->getPointerOperand();
+ } else if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
if (!ClInstrumentAtomics) return nullptr;
*IsWrite = true;
+ *TypeSize = DL.getTypeStoreSizeInBits(XCHG->getCompareOperand()->getType());
*Alignment = 0;
- return XCHG->getPointerOperand();
+ PtrOperand = XCHG->getPointerOperand();
}
- return nullptr;
+
+ // Treat memory accesses to promotable allocas as non-interesting since they
+ // will not cause memory violations. This greatly speeds up the instrumented
+ // executable at -O0.
+ if (ClSkipPromotableAllocas)
+ if (auto AI = dyn_cast_or_null<AllocaInst>(PtrOperand))
+ return isInterestingAlloca(*AI) ? AI : nullptr;
+
+ return PtrOperand;
}
static bool isPointerOperand(Value *V) {
// the frontend.
static bool isInterestingPointerComparisonOrSubtraction(Instruction *I) {
if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
- if (!Cmp->isRelational())
- return false;
+ if (!Cmp->isRelational()) return false;
} else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
- if (BO->getOpcode() != Instruction::Sub)
- return false;
+ if (BO->getOpcode() != Instruction::Sub) return false;
} else {
return false;
}
if (!isPointerOperand(I->getOperand(0)) ||
!isPointerOperand(I->getOperand(1)))
- return false;
+ return false;
return true;
}
return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
}
-void
-AddressSanitizer::instrumentPointerComparisonOrSubtraction(Instruction *I) {
+void AddressSanitizer::instrumentPointerComparisonOrSubtraction(
+ Instruction *I) {
IRBuilder<> IRB(I);
Function *F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
IRB.CreateCall2(F, Param[0], Param[1]);
}
-void AddressSanitizer::instrumentMop(Instruction *I, bool UseCalls) {
+void AddressSanitizer::instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis,
+ Instruction *I, bool UseCalls,
+ const DataLayout &DL) {
bool IsWrite = false;
unsigned Alignment = 0;
- Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &Alignment);
+ uint64_t TypeSize = 0;
+ Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &TypeSize, &Alignment);
assert(Addr);
+
+ // Optimization experiments.
+ // The experiments can be used to evaluate potential optimizations that remove
+ // instrumentation (assess false negatives). Instead of completely removing
+ // some instrumentation, you set Exp to a non-zero value (mask of optimization
+ // experiments that want to remove instrumentation of this instruction).
+ // If Exp is non-zero, this pass will emit special calls into runtime
+ // (e.g. __asan_report_exp_load1 instead of __asan_report_load1). These calls
+ // make runtime terminate the program in a special way (with a different
+ // exit status). Then you run the new compiler on a buggy corpus, collect
+ // the special terminations (ideally, you don't see them at all -- no false
+ // negatives) and make the decision on the optimization.
+ uint32_t Exp = ClForceExperiment;
+
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 || 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;
- }
- }
+ // If initialization order checking is disabled, a simple access to a
+ // dynamically initialized global is always valid.
+ GlobalVariable *G = dyn_cast<GlobalVariable>(GetUnderlyingObject(Addr, DL));
+ if (G != NULL && (!ClInitializers || GlobalIsLinkerInitialized(G)) &&
+ isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
+ NumOptimizedAccessesToGlobalVar++;
+ return;
}
}
- Type *OrigPtrTy = Addr->getType();
- Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
-
- assert(OrigTy->isSized());
- uint32_t TypeSize = DL->getTypeStoreSizeInBits(OrigTy);
-
- assert((TypeSize % 8) == 0);
+ if (ClOpt && ClOptStack) {
+ // A direct inbounds access to a stack variable is always valid.
+ if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
+ isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
+ NumOptimizedAccessesToStackVar++;
+ return;
+ }
+ }
if (IsWrite)
NumInstrumentedWrites++;
if ((TypeSize == 8 || TypeSize == 16 || TypeSize == 32 || TypeSize == 64 ||
TypeSize == 128) &&
(Alignment >= Granularity || Alignment == 0 || Alignment >= TypeSize / 8))
- return instrumentAddress(I, I, Addr, TypeSize, IsWrite, nullptr, UseCalls);
- // Instrument unusual size or unusual alignment.
- // We can not do it with a single check, so we do 1-byte check for the first
- // and the last bytes. We call __asan_report_*_n(addr, real_size) to be able
- // to report the actual access size.
- IRBuilder<> IRB(I);
- Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
- Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
- if (UseCalls) {
- IRB.CreateCall2(AsanMemoryAccessCallbackSized[IsWrite], AddrLong, Size);
- } else {
- Value *LastByte = IRB.CreateIntToPtr(
- IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
- OrigPtrTy);
- instrumentAddress(I, I, Addr, 8, IsWrite, Size, false);
- instrumentAddress(I, I, LastByte, 8, IsWrite, Size, false);
- }
+ return instrumentAddress(I, I, Addr, TypeSize, IsWrite, nullptr, UseCalls,
+ Exp);
+ instrumentUnusualSizeOrAlignment(I, Addr, TypeSize, IsWrite, nullptr,
+ UseCalls, Exp);
}
// Validate the result of Module::getOrInsertFunction called for an interface
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");
+ report_fatal_error(
+ "trying to redefine an AddressSanitizer "
+ "interface function");
}
-Instruction *AddressSanitizer::generateCrashCode(
- Instruction *InsertBefore, Value *Addr,
- bool IsWrite, size_t AccessSizeIndex, Value *SizeArgument) {
+Instruction *AddressSanitizer::generateCrashCode(Instruction *InsertBefore,
+ Value *Addr, bool IsWrite,
+ size_t AccessSizeIndex,
+ Value *SizeArgument,
+ uint32_t Exp) {
IRBuilder<> IRB(InsertBefore);
- CallInst *Call = SizeArgument
- ? IRB.CreateCall2(AsanErrorCallbackSized[IsWrite], Addr, SizeArgument)
- : IRB.CreateCall(AsanErrorCallback[IsWrite][AccessSizeIndex], Addr);
+ Value *ExpVal = Exp == 0 ? nullptr : ConstantInt::get(IRB.getInt32Ty(), Exp);
+ CallInst *Call = nullptr;
+ if (SizeArgument) {
+ if (Exp == 0)
+ Call = IRB.CreateCall2(AsanErrorCallbackSized[IsWrite][0], Addr,
+ SizeArgument);
+ else
+ Call = IRB.CreateCall3(AsanErrorCallbackSized[IsWrite][1], Addr,
+ SizeArgument, ExpVal);
+ } else {
+ if (Exp == 0)
+ Call =
+ IRB.CreateCall(AsanErrorCallback[IsWrite][0][AccessSizeIndex], Addr);
+ else
+ Call = IRB.CreateCall2(AsanErrorCallback[IsWrite][1][AccessSizeIndex],
+ Addr, ExpVal);
+ }
// We don't do Call->setDoesNotReturn() because the BB already has
// UnreachableInst at the end.
}
Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
- Value *ShadowValue,
- uint32_t TypeSize) {
+ Value *ShadowValue,
+ uint32_t TypeSize) {
size_t Granularity = 1 << Mapping.Scale;
// Addr & (Granularity - 1)
- Value *LastAccessedByte = IRB.CreateAnd(
- AddrLong, ConstantInt::get(IntptrTy, 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);
+ 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,
Instruction *InsertBefore, Value *Addr,
uint32_t TypeSize, bool IsWrite,
- Value *SizeArgument, bool UseCalls) {
+ Value *SizeArgument, bool UseCalls,
+ uint32_t Exp) {
IRBuilder<> IRB(InsertBefore);
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
if (UseCalls) {
- IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][AccessSizeIndex],
- AddrLong);
+ if (Exp == 0)
+ IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][0][AccessSizeIndex],
+ AddrLong);
+ else
+ IRB.CreateCall2(AsanMemoryAccessCallback[IsWrite][1][AccessSizeIndex],
+ AddrLong, ConstantInt::get(IRB.getInt32Ty(), Exp));
return;
}
- Type *ShadowTy = IntegerType::get(
- *C, std::max(8U, TypeSize >> Mapping.Scale));
+ 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 *ShadowValue =
+ IRB.CreateLoad(IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
size_t Granularity = 1 << Mapping.Scale;
if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
// We use branch weights for the slow path check, to indicate that the slow
// path is rarely taken. This seems to be the case for SPEC benchmarks.
- TerminatorInst *CheckTerm =
- SplitBlockAndInsertIfThen(Cmp, InsertBefore, false,
- MDBuilder(*C).createBranchWeights(1, 100000));
+ TerminatorInst *CheckTerm = SplitBlockAndInsertIfThen(
+ Cmp, InsertBefore, false, MDBuilder(*C).createBranchWeights(1, 100000));
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, true);
}
- Instruction *Crash = generateCrashCode(
- CrashTerm, AddrLong, IsWrite, AccessSizeIndex, SizeArgument);
+ Instruction *Crash = generateCrashCode(CrashTerm, AddrLong, IsWrite,
+ AccessSizeIndex, SizeArgument, Exp);
Crash->setDebugLoc(OrigIns->getDebugLoc());
}
+// Instrument unusual size or unusual alignment.
+// We can not do it with a single check, so we do 1-byte check for the first
+// and the last bytes. We call __asan_report_*_n(addr, real_size) to be able
+// to report the actual access size.
+void AddressSanitizer::instrumentUnusualSizeOrAlignment(
+ Instruction *I, Value *Addr, uint32_t TypeSize, bool IsWrite,
+ Value *SizeArgument, bool UseCalls, uint32_t Exp) {
+ IRBuilder<> IRB(I);
+ Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
+ Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
+ if (UseCalls) {
+ if (Exp == 0)
+ IRB.CreateCall2(AsanMemoryAccessCallbackSized[IsWrite][0], AddrLong,
+ Size);
+ else
+ IRB.CreateCall3(AsanMemoryAccessCallbackSized[IsWrite][1], AddrLong, Size,
+ ConstantInt::get(IRB.getInt32Ty(), Exp));
+ } else {
+ Value *LastByte = IRB.CreateIntToPtr(
+ IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
+ Addr->getType());
+ instrumentAddress(I, I, Addr, 8, IsWrite, Size, false, Exp);
+ instrumentAddress(I, I, LastByte, 8, IsWrite, Size, false, Exp);
+ }
+}
+
void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit,
GlobalValue *ModuleName) {
// Set up the arguments to our poison/unpoison functions.
ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
for (Use &OP : CA->operands()) {
- if (isa<ConstantAggregateZero>(OP))
- continue;
+ if (isa<ConstantAggregateZero>(OP)) continue;
ConstantStruct *CS = cast<ConstantStruct>(OP);
// Must have a function or null ptr.
- if (Function* F = dyn_cast<Function>(CS->getOperand(1))) {
+ if (Function *F = dyn_cast<Function>(CS->getOperand(1))) {
if (F->getName() == kAsanModuleCtorName) continue;
ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
// Don't instrument CTORs that will run before asan.module_ctor.
G->getLinkage() != GlobalVariable::PrivateLinkage &&
G->getLinkage() != GlobalVariable::InternalLinkage)
return false;
- if (G->hasComdat())
- return false;
+ if (G->hasComdat()) 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;
+ if (G->isThreadLocal()) return false;
// For now, just ignore this Global if the alignment is large.
if (G->getAlignment() > MinRedzoneSizeForGlobal()) 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.startswith("__OBJC,") ||
- Section.startswith("__DATA, __objc_")) {
- DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
- 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.startswith("__DATA,__cfstring")) {
- DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
- return false;
- }
- // The linker merges the contents of cstring_literals and removes the
- // trailing zeroes.
- if (Section.startswith("__TEXT,__cstring,cstring_literals")) {
- DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
- return false;
- }
- if (Section.startswith("__TEXT,__objc_methname,cstring_literals")) {
- DEBUG(dbgs() << "Ignoring objc_methname cstring global: " << *G << "\n");
- return false;
- }
+ if (TargetTriple.isOSBinFormatMachO()) {
+ StringRef ParsedSegment, ParsedSection;
+ unsigned TAA = 0, StubSize = 0;
+ bool TAAParsed;
+ std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(
+ Section, ParsedSegment, ParsedSection, TAA, TAAParsed, StubSize);
+ if (!ErrorCode.empty()) {
+ report_fatal_error("Invalid section specifier '" + ParsedSection +
+ "': " + ErrorCode + ".");
+ }
+
+ // 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 (ParsedSegment == "__OBJC" ||
+ (ParsedSegment == "__DATA" && ParsedSection.startswith("__objc_"))) {
+ DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
+ 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 (ParsedSegment == "__DATA" && ParsedSection == "__cfstring") {
+ DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
+ return false;
+ }
+ // The linker merges the contents of cstring_literals and removes the
+ // trailing zeroes.
+ if (ParsedSegment == "__TEXT" && (TAA & MachO::S_CSTRING_LITERALS)) {
+ DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
+ return false;
+ }
+ }
// Callbacks put into the CRT initializer/terminator sections
// should not be instrumented.
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
// Declare functions that register/unregister globals.
AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanRegisterGlobalsName, IRB.getVoidTy(),
- IntptrTy, IntptrTy, nullptr));
+ kAsanRegisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
- AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanUnregisterGlobalsName,
- IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
+ AsanUnregisterGlobals = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanUnregisterGlobalsName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, nullptr));
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
}
SmallVector<GlobalVariable *, 16> GlobalsToChange;
for (auto &G : M.globals()) {
- if (ShouldInstrumentGlobal(&G))
- GlobalsToChange.push_back(&G);
+ if (ShouldInstrumentGlobal(&G)) GlobalsToChange.push_back(&G);
}
size_t n = GlobalsToChange.size();
// We shouldn't merge same module names, as this string serves as unique
// module ID in runtime.
GlobalVariable *ModuleName = createPrivateGlobalForString(
- M, M.getModuleIdentifier(), /*AllowMerging*/false);
+ M, M.getModuleIdentifier(), /*AllowMerging*/ false);
+ auto &DL = M.getDataLayout();
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 = DL->getTypeAllocSize(Ty);
+ uint64_t SizeInBytes = DL.getTypeAllocSize(Ty);
uint64_t MinRZ = MinRedzoneSizeForGlobal();
// MinRZ <= RZ <= kMaxGlobalRedzone
// and trying to make RZ to be ~ 1/4 of SizeInBytes.
- uint64_t RZ = std::max(MinRZ,
- std::min(kMaxGlobalRedzone,
- (SizeInBytes / MinRZ / 4) * MinRZ));
+ uint64_t RZ = std::max(
+ MinRZ, std::min(kMaxGlobalRedzone, (SizeInBytes / MinRZ / 4) * MinRZ));
uint64_t RightRedzoneSize = RZ;
// Round up to MinRZ
- if (SizeInBytes % MinRZ)
- RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
+ if (SizeInBytes % MinRZ) RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
StructType *NewTy = StructType::get(Ty, RightRedZoneTy, nullptr);
- Constant *NewInitializer = ConstantStruct::get(
- NewTy, G->getInitializer(),
- Constant::getNullValue(RightRedZoneTy), nullptr);
+ Constant *NewInitializer =
+ ConstantStruct::get(NewTy, G->getInitializer(),
+ Constant::getNullValue(RightRedZoneTy), nullptr);
// Create a new global variable with enough space for a redzone.
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());
+ GlobalVariable *NewGlobal =
+ new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer,
+ "", G, G->getThreadLocalMode());
NewGlobal->copyAttributesFrom(G);
NewGlobal->setAlignment(MinRZ);
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, nullptr);
- if (ClInitializers && MD.IsDynInit)
- HasDynamicallyInitializedGlobals = true;
+ if (ClInitializers && MD.IsDynInit) HasDynamicallyInitializedGlobals = true;
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\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);
+ 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,
}
bool AddressSanitizerModule::runOnModule(Module &M) {
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- if (!DLP)
- return false;
- DL = &DLP->getDataLayout();
C = &(M.getContext());
- int LongSize = DL->getPointerSizeInBits();
+ int LongSize = M.getDataLayout().getPointerSizeInBits();
IntptrTy = Type::getIntNTy(*C, LongSize);
- Mapping = getShadowMapping(M, LongSize);
+ TargetTriple = Triple(M.getTargetTriple());
+ Mapping = getShadowMapping(TargetTriple, LongSize);
initializeCallbacks(M);
bool Changed = false;
assert(CtorFunc);
IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
- if (ClGlobals)
- Changed |= InstrumentGlobals(IRB, M);
+ if (ClGlobals) Changed |= InstrumentGlobals(IRB, M);
return Changed;
}
void AddressSanitizer::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
// 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 Suffix =
- (AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
- AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
- checkInterfaceFunction(
- M.getOrInsertFunction(kAsanReportErrorTemplate + Suffix,
- IRB.getVoidTy(), IntptrTy, nullptr));
- AsanMemoryAccessCallback[AccessIsWrite][AccessSizeIndex] =
- checkInterfaceFunction(
- M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + Suffix,
- IRB.getVoidTy(), IntptrTy, nullptr));
+ // IsWrite, TypeSize and Exp are encoded in the function name.
+ for (int Exp = 0; Exp < 2; Exp++) {
+ for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
+ const std::string TypeStr = AccessIsWrite ? "store" : "load";
+ const std::string ExpStr = Exp ? "exp_" : "";
+ const Type *ExpType = Exp ? Type::getInt32Ty(*C) : nullptr;
+ AsanErrorCallbackSized[AccessIsWrite][Exp] =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanReportErrorTemplate + ExpStr + TypeStr + "_n",
+ IRB.getVoidTy(), IntptrTy, IntptrTy, ExpType, nullptr));
+ AsanMemoryAccessCallbackSized[AccessIsWrite][Exp] =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ ClMemoryAccessCallbackPrefix + ExpStr + TypeStr + "N",
+ IRB.getVoidTy(), IntptrTy, IntptrTy, ExpType, nullptr));
+ for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
+ AccessSizeIndex++) {
+ const std::string Suffix = TypeStr + itostr(1 << AccessSizeIndex);
+ AsanErrorCallback[AccessIsWrite][Exp][AccessSizeIndex] =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanReportErrorTemplate + ExpStr + Suffix, IRB.getVoidTy(),
+ IntptrTy, ExpType, nullptr));
+ AsanMemoryAccessCallback[AccessIsWrite][Exp][AccessSizeIndex] =
+ checkInterfaceFunction(M.getOrInsertFunction(
+ ClMemoryAccessCallbackPrefix + ExpStr + Suffix, IRB.getVoidTy(),
+ IntptrTy, ExpType, nullptr));
+ }
}
}
- AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
- AsanErrorCallbackSized[1] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanReportStoreN, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
-
- AsanMemoryAccessCallbackSized[0] = checkInterfaceFunction(
- M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "loadN",
- IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
- AsanMemoryAccessCallbackSized[1] = checkInterfaceFunction(
- M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + "storeN",
- IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanMemmove = checkInterfaceFunction(M.getOrInsertFunction(
ClMemoryAccessCallbackPrefix + "memmove", IRB.getInt8PtrTy(),
// virtual
bool AddressSanitizer::doInitialization(Module &M) {
// Initialize the private fields. No one has accessed them before.
- DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
- if (!DLP)
- report_fatal_error("data layout missing");
- DL = &DLP->getDataLayout();
GlobalsMD.init(M);
C = &(M.getContext());
- LongSize = DL->getPointerSizeInBits();
+ LongSize = M.getDataLayout().getPointerSizeInBits();
IntptrTy = Type::getIntNTy(*C, LongSize);
+ TargetTriple = Triple(M.getTargetTriple());
- AsanCtorFunction = Function::Create(
- FunctionType::get(Type::getVoidTy(*C), false),
- GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
+ AsanCtorFunction =
+ Function::Create(FunctionType::get(Type::getVoidTy(*C), false),
+ GlobalValue::InternalLinkage, kAsanModuleCtorName, &M);
BasicBlock *AsanCtorBB = BasicBlock::Create(*C, "", AsanCtorFunction);
// call __asan_init in the module ctor.
IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
AsanInitFunction->setLinkage(Function::ExternalLinkage);
IRB.CreateCall(AsanInitFunction);
- Mapping = getShadowMapping(M, LongSize);
+ Mapping = getShadowMapping(TargetTriple, LongSize);
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
return true;
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
initializeCallbacks(*F.getParent());
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+
// If needed, insert __asan_init before checking for SanitizeAddress attr.
maybeInsertAsanInitAtFunctionEntry(F);
- if (!F.hasFnAttribute(Attribute::SanitizeAddress))
- return false;
+ if (!F.hasFnAttribute(Attribute::SanitizeAddress)) return false;
- if (!ClDebugFunc.empty() && ClDebugFunc != F.getName())
- 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;
- SmallVector<BasicBlock*, 16> AllBlocks;
- SmallVector<Instruction*, 16> PointerComparisonsOrSubtracts;
+ SmallSet<Value *, 16> TempsToInstrument;
+ SmallVector<Instruction *, 16> ToInstrument;
+ SmallVector<Instruction *, 8> NoReturnCalls;
+ SmallVector<BasicBlock *, 16> AllBlocks;
+ SmallVector<Instruction *, 16> PointerComparisonsOrSubtracts;
int NumAllocas = 0;
bool IsWrite;
unsigned Alignment;
+ uint64_t TypeSize;
// Fill the set of memory operations to instrument.
for (auto &BB : F) {
int NumInsnsPerBB = 0;
for (auto &Inst : BB) {
if (LooksLikeCodeInBug11395(&Inst)) return false;
- if (Value *Addr =
- isInterestingMemoryAccess(&Inst, &IsWrite, &Alignment)) {
+ if (Value *Addr = isInterestingMemoryAccess(&Inst, &IsWrite, &TypeSize,
+ &Alignment)) {
if (ClOpt && ClOptSameTemp) {
if (!TempsToInstrument.insert(Addr).second)
continue; // We've seen this temp in the current BB.
} else if (isa<MemIntrinsic>(Inst)) {
// ok, take it.
} else {
- if (isa<AllocaInst>(Inst))
- NumAllocas++;
+ if (isa<AllocaInst>(Inst)) NumAllocas++;
CallSite CS(&Inst);
if (CS) {
// A call inside BB.
TempsToInstrument.clear();
- if (CS.doesNotReturn())
- NoReturnCalls.push_back(CS.getInstruction());
+ if (CS.doesNotReturn()) NoReturnCalls.push_back(CS.getInstruction());
}
continue;
}
ToInstrument.push_back(&Inst);
NumInsnsPerBB++;
- if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB)
- break;
+ if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) break;
}
}
- Function *UninstrumentedDuplicate = nullptr;
- 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);
- }
-
bool UseCalls = false;
if (ClInstrumentationWithCallsThreshold >= 0 &&
ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold)
UseCalls = true;
+ const TargetLibraryInfo *TLI =
+ &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+ const DataLayout &DL = F.getParent()->getDataLayout();
+ ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(),
+ /*RoundToAlign=*/true);
+
// Instrument.
int NumInstrumented = 0;
for (auto Inst : ToInstrument) {
if (ClDebugMin < 0 || ClDebugMax < 0 ||
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
- if (isInterestingMemoryAccess(Inst, &IsWrite, &Alignment))
- instrumentMop(Inst, UseCalls);
+ if (isInterestingMemoryAccess(Inst, &IsWrite, &TypeSize, &Alignment))
+ instrumentMop(ObjSizeVis, Inst, UseCalls,
+ F.getParent()->getDataLayout());
else
instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
}
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
- if (ClKeepUninstrumented) {
- if (!res) {
- // No instrumentation is done, no need for the duplicate.
- if (UninstrumentedDuplicate)
- UninstrumentedDuplicate->eraseFromParent();
- } else {
- // The function was instrumented. We must have the duplicate.
- assert(UninstrumentedDuplicate);
- UninstrumentedDuplicate->setSection("NOASAN");
- assert(!F.hasSection());
- F.setSection("ASAN");
- }
- }
-
return res;
}
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, nullptr));
- AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
- IntptrTy, IntptrTy, nullptr));
+ AsanStackMallocFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanStackMallocNameTemplate + Suffix, IntptrTy, IntptrTy, nullptr));
+ AsanStackFreeFunc[i] = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanStackFreeNameTemplate + Suffix,
+ IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
}
AsanPoisonStackMemoryFunc = checkInterfaceFunction(
M.getOrInsertFunction(kAsanPoisonStackMemoryName, IRB.getVoidTy(),
IntptrTy, IntptrTy, nullptr));
}
-void
-FunctionStackPoisoner::poisonRedZones(ArrayRef<uint8_t> ShadowBytes,
- IRBuilder<> &IRB, Value *ShadowBase,
- bool DoPoison) {
+void FunctionStackPoisoner::poisonRedZones(ArrayRef<uint8_t> ShadowBytes,
+ IRBuilder<> &IRB, Value *ShadowBase,
+ bool DoPoison) {
size_t n = ShadowBytes.size();
size_t i = 0;
// We need to (un)poison n bytes of stack shadow. Poison as many as we can
for (; i + LargeStoreSizeInBytes - 1 < n; i += LargeStoreSizeInBytes) {
uint64_t Val = 0;
for (size_t j = 0; j < LargeStoreSizeInBytes; j++) {
- if (ASan.DL->isLittleEndian())
+ if (F.getParent()->getDataLayout().isLittleEndian())
Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
else
Val = (Val << 8) | ShadowBytes[i + j];
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;
+ 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);
+
+ // kAsanStackAfterReturnMagic is 0xf5.
+ const uint64_t kAsanStackAfterReturnMagic64 = 0xf5f5f5f5f5f5f5f5ULL;
+
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()));
+ IRB.CreateStore(
+ ConstantInt::get(IRB.getInt64Ty(), kAsanStackAfterReturnMagic64),
+ IRB.CreateIntToPtr(p, IRB.getInt64Ty()->getPointerTo()));
}
}
static DebugLoc getFunctionEntryDebugLocation(Function &F) {
for (const auto &Inst : F.getEntryBlock())
- if (!isa<AllocaInst>(Inst))
- return Inst.getDebugLoc();
+ if (!isa<AllocaInst>(Inst)) return Inst.getDebugLoc();
return DebugLoc();
}
+PHINode *FunctionStackPoisoner::createPHI(IRBuilder<> &IRB, Value *Cond,
+ Value *ValueIfTrue,
+ Instruction *ThenTerm,
+ Value *ValueIfFalse) {
+ PHINode *PHI = IRB.CreatePHI(IntptrTy, 2);
+ BasicBlock *CondBlock = cast<Instruction>(Cond)->getParent();
+ PHI->addIncoming(ValueIfFalse, CondBlock);
+ BasicBlock *ThenBlock = ThenTerm->getParent();
+ PHI->addIncoming(ValueIfTrue, ThenBlock);
+ return PHI;
+}
+
+Value *FunctionStackPoisoner::createAllocaForLayout(
+ IRBuilder<> &IRB, const ASanStackFrameLayout &L, bool Dynamic) {
+ AllocaInst *Alloca;
+ if (Dynamic) {
+ Alloca = IRB.CreateAlloca(IRB.getInt8Ty(),
+ ConstantInt::get(IRB.getInt64Ty(), L.FrameSize),
+ "MyAlloca");
+ } else {
+ Alloca = IRB.CreateAlloca(ArrayType::get(IRB.getInt8Ty(), L.FrameSize),
+ nullptr, "MyAlloca");
+ assert(Alloca->isStaticAlloca());
+ }
+ assert((ClRealignStack & (ClRealignStack - 1)) == 0);
+ size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
+ Alloca->setAlignment(FrameAlignment);
+ return IRB.CreatePointerCast(Alloca, IntptrTy);
+}
+
void FunctionStackPoisoner::poisonStack() {
+ assert(AllocaVec.size() > 0 || DynamicAllocaVec.size() > 0);
+
+ if (ClInstrumentAllocas) {
+ // Handle dynamic allocas.
+ for (auto &AllocaCall : DynamicAllocaVec) {
+ handleDynamicAllocaCall(AllocaCall);
+ unpoisonDynamicAlloca(AllocaCall);
+ }
+ }
+
+ if (AllocaVec.size() == 0) return;
+
int StackMallocIdx = -1;
DebugLoc EntryDebugLocation = getFunctionEntryDebugLocation(F);
- assert(AllocaVec.size() > 0);
Instruction *InsBefore = AllocaVec[0];
IRBuilder<> IRB(InsBefore);
IRB.SetCurrentDebugLocation(EntryDebugLocation);
SmallVector<ASanStackVariableDescription, 16> SVD;
SVD.reserve(AllocaVec.size());
for (AllocaInst *AI : AllocaVec) {
- ASanStackVariableDescription D = { AI->getName().data(),
- getAllocaSizeInBytes(AI),
- AI->getAlignment(), AI, 0};
+ ASanStackVariableDescription D = {AI->getName().data(),
+ ASan.getAllocaSizeInBytes(AI),
+ AI->getAlignment(), AI, 0};
SVD.push_back(D);
}
// Minimal header size (left redzone) is 4 pointers,
uint64_t LocalStackSize = L.FrameSize;
bool DoStackMalloc =
ClUseAfterReturn && LocalStackSize <= kMaxStackMallocSize;
+ // Don't do dynamic alloca in presence of inline asm: too often it
+ // makes assumptions on which registers are available.
+ bool DoDynamicAlloca = ClDynamicAllocaStack && !HasNonEmptyInlineAsm;
- Type *ByteArrayTy = ArrayType::get(IRB.getInt8Ty(), LocalStackSize);
- AllocaInst *MyAlloca =
- new AllocaInst(ByteArrayTy, "MyAlloca", InsBefore);
- MyAlloca->setDebugLoc(EntryDebugLocation);
- 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;
+ Value *StaticAlloca =
+ DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);
+
+ Value *FakeStack;
+ Value *LocalStackBase;
if (DoStackMalloc) {
- // LocalStackBase = OrigStackBase
- // if (__asan_option_detect_stack_use_after_return)
- // LocalStackBase = __asan_stack_malloc_N(LocalStackBase, OrigStackBase);
- StackMallocIdx = StackMallocSizeClass(LocalStackSize);
- assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
+ // void *FakeStack = __asan_option_detect_stack_use_after_return
+ // ? __asan_stack_malloc_N(LocalStackSize)
+ // : nullptr;
+ // void *LocalStackBase = (FakeStack) ? FakeStack : alloca(LocalStackSize);
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();
+ Value *UARIsEnabled =
+ IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR),
+ Constant::getNullValue(IRB.getInt32Ty()));
+ Instruction *Term =
+ SplitBlockAndInsertIfThen(UARIsEnabled, InsBefore, false);
IRBuilder<> IRBIf(Term);
IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
- LocalStackBase = IRBIf.CreateCall2(
- AsanStackMallocFunc[StackMallocIdx],
- ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
- BasicBlock *SetBlock = cast<Instruction>(LocalStackBase)->getParent();
+ StackMallocIdx = StackMallocSizeClass(LocalStackSize);
+ assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
+ Value *FakeStackValue =
+ IRBIf.CreateCall(AsanStackMallocFunc[StackMallocIdx],
+ ConstantInt::get(IntptrTy, LocalStackSize));
IRB.SetInsertPoint(InsBefore);
IRB.SetCurrentDebugLocation(EntryDebugLocation);
- PHINode *Phi = IRB.CreatePHI(IntptrTy, 2);
- Phi->addIncoming(OrigStackBase, CmpBlock);
- Phi->addIncoming(LocalStackBase, SetBlock);
- LocalStackBase = Phi;
+ FakeStack = createPHI(IRB, UARIsEnabled, FakeStackValue, Term,
+ ConstantInt::get(IntptrTy, 0));
+
+ Value *NoFakeStack =
+ IRB.CreateICmpEQ(FakeStack, Constant::getNullValue(IntptrTy));
+ Term = SplitBlockAndInsertIfThen(NoFakeStack, InsBefore, false);
+ IRBIf.SetInsertPoint(Term);
+ IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
+ Value *AllocaValue =
+ DoDynamicAlloca ? createAllocaForLayout(IRBIf, L, true) : StaticAlloca;
+ IRB.SetInsertPoint(InsBefore);
+ IRB.SetCurrentDebugLocation(EntryDebugLocation);
+ LocalStackBase = createPHI(IRB, NoFakeStack, AllocaValue, Term, FakeStack);
+ } else {
+ // void *FakeStack = nullptr;
+ // void *LocalStackBase = alloca(LocalStackSize);
+ FakeStack = ConstantInt::get(IntptrTy, 0);
+ LocalStackBase =
+ DoDynamicAlloca ? createAllocaForLayout(IRB, L, true) : StaticAlloca;
}
// Insert poison calls for lifetime intrinsics for alloca.
Value *NewAllocaPtr = IRB.CreateIntToPtr(
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
AI->getType());
- replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
+ replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB, /*Deref=*/true);
AI->replaceAllUsesWith(NewAllocaPtr);
}
BasePlus0);
// Write the frame description constant to redzone[1].
Value *BasePlus1 = IRB.CreateIntToPtr(
- IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)),
- IntptrPtrTy);
+ IRB.CreateAdd(LocalStackBase,
+ ConstantInt::get(IntptrTy, ASan.LongSize / 8)),
+ IntptrPtrTy);
GlobalVariable *StackDescriptionGlobal =
createPrivateGlobalForString(*F.getParent(), L.DescriptionString,
- /*AllowMerging*/true);
- Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal,
- IntptrTy);
+ /*AllowMerging*/ true);
+ Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
IRB.CreateStore(Description, BasePlus1);
// Write the PC to redzone[2].
Value *BasePlus2 = IRB.CreateIntToPtr(
- IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy,
- 2 * ASan.LongSize/8)),
- IntptrPtrTy);
+ IRB.CreateAdd(LocalStackBase,
+ ConstantInt::get(IntptrTy, 2 * ASan.LongSize / 8)),
+ IntptrPtrTy);
IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2);
// Poison the stack redzones at the entry.
BasePlus0);
if (DoStackMalloc) {
assert(StackMallocIdx >= 0);
- // if LocalStackBase != OrigStackBase:
+ // if FakeStack != 0 // LocalStackBase == FakeStack
// // In use-after-return mode, poison the whole stack frame.
// if StackMallocIdx <= 4
// // For small sizes inline the whole thing:
// memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize);
- // **SavedFlagPtr(LocalStackBase) = 0
+ // **SavedFlagPtr(FakeStack) = 0
// else
- // __asan_stack_free_N(LocalStackBase, OrigStackBase)
+ // __asan_stack_free_N(FakeStack, LocalStackSize)
// else
// <This is not a fake stack; unpoison the redzones>
- Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase);
+ Value *Cmp =
+ IRBRet.CreateICmpNE(FakeStack, Constant::getNullValue(IntptrTy));
TerminatorInst *ThenTerm, *ElseTerm;
SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
SetShadowToStackAfterReturnInlined(IRBPoison, ShadowBase,
ClassSize >> Mapping.Scale);
Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
- LocalStackBase,
+ FakeStack,
ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
Value *SavedFlagPtr = IRBPoison.CreateLoad(
IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
} else {
// For larger frames call __asan_stack_free_*.
- IRBPoison.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase,
- ConstantInt::get(IntptrTy, LocalStackSize),
- OrigStackBase);
+ IRBPoison.CreateCall2(AsanStackFreeFunc[StackMallocIdx], FakeStack,
+ ConstantInt::get(IntptrTy, LocalStackSize));
}
IRBuilder<> IRBElse(ElseTerm);
} else if (HavePoisonedAllocas) {
// If we poisoned some allocas in llvm.lifetime analysis,
// unpoison whole stack frame now.
- assert(LocalStackBase == OrigStackBase);
poisonAlloca(LocalStackBase, LocalStackSize, IRBRet, false);
} else {
poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false);
}
// We are done. Remove the old unused alloca instructions.
- for (auto AI : AllocaVec)
- AI->eraseFromParent();
+ for (auto AI : AllocaVec) AI->eraseFromParent();
}
void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
// For now just insert the call to ASan runtime.
Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy);
Value *SizeArg = ConstantInt::get(IntptrTy, Size);
- IRB.CreateCall2(DoPoison ? AsanPoisonStackMemoryFunc
- : AsanUnpoisonStackMemoryFunc,
- AddrArg, SizeArg);
+ IRB.CreateCall2(
+ DoPoison ? AsanPoisonStackMemoryFunc : AsanUnpoisonStackMemoryFunc,
+ AddrArg, SizeArg);
}
// Handling llvm.lifetime intrinsics for a given %alloca:
AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
// We're intested only in allocas we can handle.
- return isInterestingAlloca(*AI) ? AI : nullptr;
+ return ASan.isInterestingAlloca(*AI) ? AI : nullptr;
// See if we've already calculated (or started to calculate) alloca for a
// given value.
AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
- if (I != AllocaForValue.end())
- return I->second;
+ if (I != AllocaForValue.end()) return I->second;
// Store 0 while we're calculating alloca for value V to avoid
// infinite recursion if the value references itself.
AllocaForValue[V] = nullptr;
Res = IncValueAI;
}
}
- if (Res)
- AllocaForValue[V] = Res;
+ if (Res) AllocaForValue[V] = Res;
return Res;
}
+
+// Compute PartialRzMagic for dynamic alloca call. PartialRzMagic is
+// constructed from two separate 32-bit numbers: PartialRzMagic = Val1 | Val2.
+// (1) Val1 is resposible for forming base value for PartialRzMagic, containing
+// only 00 for fully addressable and 0xcb for fully poisoned bytes for each
+// 8-byte chunk of user memory respectively.
+// (2) Val2 forms the value for marking first poisoned byte in shadow memory
+// with appropriate value (0x01 - 0x07 or 0xcb if Padding % 8 == 0).
+
+// Shift = Padding & ~7; // the number of bits we need to shift to access first
+// chunk in shadow memory, containing nonzero bytes.
+// Example:
+// Padding = 21 Padding = 16
+// Shadow: |00|00|05|cb| Shadow: |00|00|cb|cb|
+// ^ ^
+// | |
+// Shift = 21 & ~7 = 16 Shift = 16 & ~7 = 16
+//
+// Val1 = 0xcbcbcbcb << Shift;
+// PartialBits = Padding ? Padding & 7 : 0xcb;
+// Val2 = PartialBits << Shift;
+// Result = Val1 | Val2;
+Value *FunctionStackPoisoner::computePartialRzMagic(Value *PartialSize,
+ IRBuilder<> &IRB) {
+ PartialSize = IRB.CreateIntCast(PartialSize, IRB.getInt32Ty(), false);
+ Value *Shift = IRB.CreateAnd(PartialSize, IRB.getInt32(~7));
+ unsigned Val1Int = kAsanAllocaPartialVal1;
+ unsigned Val2Int = kAsanAllocaPartialVal2;
+ if (!F.getParent()->getDataLayout().isLittleEndian()) {
+ Val1Int = sys::getSwappedBytes(Val1Int);
+ Val2Int = sys::getSwappedBytes(Val2Int);
+ }
+ Value *Val1 = shiftAllocaMagic(IRB.getInt32(Val1Int), IRB, Shift);
+ Value *PartialBits = IRB.CreateAnd(PartialSize, IRB.getInt32(7));
+ // For BigEndian get 0x000000YZ -> 0xYZ000000.
+ if (F.getParent()->getDataLayout().isBigEndian())
+ PartialBits = IRB.CreateShl(PartialBits, IRB.getInt32(24));
+ Value *Val2 = IRB.getInt32(Val2Int);
+ Value *Cond =
+ IRB.CreateICmpNE(PartialBits, Constant::getNullValue(IRB.getInt32Ty()));
+ Val2 = IRB.CreateSelect(Cond, shiftAllocaMagic(PartialBits, IRB, Shift),
+ shiftAllocaMagic(Val2, IRB, Shift));
+ return IRB.CreateOr(Val1, Val2);
+}
+
+void FunctionStackPoisoner::handleDynamicAllocaCall(
+ DynamicAllocaCall &AllocaCall) {
+ AllocaInst *AI = AllocaCall.AI;
+ if (!doesDominateAllExits(AI)) {
+ // We do not yet handle complex allocas
+ AllocaCall.Poison = false;
+ return;
+ }
+
+ IRBuilder<> IRB(AI);
+
+ PointerType *Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
+ const unsigned Align = std::max(kAllocaRzSize, AI->getAlignment());
+ const uint64_t AllocaRedzoneMask = kAllocaRzSize - 1;
+
+ Value *Zero = Constant::getNullValue(IntptrTy);
+ Value *AllocaRzSize = ConstantInt::get(IntptrTy, kAllocaRzSize);
+ Value *AllocaRzMask = ConstantInt::get(IntptrTy, AllocaRedzoneMask);
+ Value *NotAllocaRzMask = ConstantInt::get(IntptrTy, ~AllocaRedzoneMask);
+
+ // Since we need to extend alloca with additional memory to locate
+ // redzones, and OldSize is number of allocated blocks with
+ // ElementSize size, get allocated memory size in bytes by
+ // OldSize * ElementSize.
+ unsigned ElementSize =
+ F.getParent()->getDataLayout().getTypeAllocSize(AI->getAllocatedType());
+ Value *OldSize = IRB.CreateMul(AI->getArraySize(),
+ ConstantInt::get(IntptrTy, ElementSize));
+
+ // PartialSize = OldSize % 32
+ Value *PartialSize = IRB.CreateAnd(OldSize, AllocaRzMask);
+
+ // Misalign = kAllocaRzSize - PartialSize;
+ Value *Misalign = IRB.CreateSub(AllocaRzSize, PartialSize);
+
+ // PartialPadding = Misalign != kAllocaRzSize ? Misalign : 0;
+ Value *Cond = IRB.CreateICmpNE(Misalign, AllocaRzSize);
+ Value *PartialPadding = IRB.CreateSelect(Cond, Misalign, Zero);
+
+ // AdditionalChunkSize = Align + PartialPadding + kAllocaRzSize
+ // Align is added to locate left redzone, PartialPadding for possible
+ // partial redzone and kAllocaRzSize for right redzone respectively.
+ Value *AdditionalChunkSize = IRB.CreateAdd(
+ ConstantInt::get(IntptrTy, Align + kAllocaRzSize), PartialPadding);
+
+ Value *NewSize = IRB.CreateAdd(OldSize, AdditionalChunkSize);
+
+ // Insert new alloca with new NewSize and Align params.
+ AllocaInst *NewAlloca = IRB.CreateAlloca(IRB.getInt8Ty(), NewSize);
+ NewAlloca->setAlignment(Align);
+
+ // NewAddress = Address + Align
+ Value *NewAddress = IRB.CreateAdd(IRB.CreatePtrToInt(NewAlloca, IntptrTy),
+ ConstantInt::get(IntptrTy, Align));
+
+ Value *NewAddressPtr = IRB.CreateIntToPtr(NewAddress, AI->getType());
+
+ // LeftRzAddress = NewAddress - kAllocaRzSize
+ Value *LeftRzAddress = IRB.CreateSub(NewAddress, AllocaRzSize);
+
+ // Poisoning left redzone.
+ AllocaCall.LeftRzAddr = ASan.memToShadow(LeftRzAddress, IRB);
+ IRB.CreateStore(ConstantInt::get(IRB.getInt32Ty(), kAsanAllocaLeftMagic),
+ IRB.CreateIntToPtr(AllocaCall.LeftRzAddr, Int32PtrTy));
+
+ // PartialRzAligned = PartialRzAddr & ~AllocaRzMask
+ Value *PartialRzAddr = IRB.CreateAdd(NewAddress, OldSize);
+ Value *PartialRzAligned = IRB.CreateAnd(PartialRzAddr, NotAllocaRzMask);
+
+ // Poisoning partial redzone.
+ Value *PartialRzMagic = computePartialRzMagic(PartialSize, IRB);
+ Value *PartialRzShadowAddr = ASan.memToShadow(PartialRzAligned, IRB);
+ IRB.CreateStore(PartialRzMagic,
+ IRB.CreateIntToPtr(PartialRzShadowAddr, Int32PtrTy));
+
+ // RightRzAddress
+ // = (PartialRzAddr + AllocaRzMask) & ~AllocaRzMask
+ Value *RightRzAddress = IRB.CreateAnd(
+ IRB.CreateAdd(PartialRzAddr, AllocaRzMask), NotAllocaRzMask);
+
+ // Poisoning right redzone.
+ AllocaCall.RightRzAddr = ASan.memToShadow(RightRzAddress, IRB);
+ IRB.CreateStore(ConstantInt::get(IRB.getInt32Ty(), kAsanAllocaRightMagic),
+ IRB.CreateIntToPtr(AllocaCall.RightRzAddr, Int32PtrTy));
+
+ // Replace all uses of AddessReturnedByAlloca with NewAddress.
+ AI->replaceAllUsesWith(NewAddressPtr);
+
+ // We are done. Erase old alloca and store left, partial and right redzones
+ // shadow addresses for future unpoisoning.
+ AI->eraseFromParent();
+ NumInstrumentedDynamicAllocas++;
+}
+
+// isSafeAccess returns true if Addr is always inbounds with respect to its
+// base object. For example, it is a field access or an array access with
+// constant inbounds index.
+bool AddressSanitizer::isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis,
+ Value *Addr, uint64_t TypeSize) const {
+ SizeOffsetType SizeOffset = ObjSizeVis.compute(Addr);
+ if (!ObjSizeVis.bothKnown(SizeOffset)) return false;
+ uint64_t Size = SizeOffset.first.getZExtValue();
+ int64_t Offset = SizeOffset.second.getSExtValue();
+ // Three checks are required to ensure safety:
+ // . Offset >= 0 (since the offset is given from the base ptr)
+ // . Size >= Offset (unsigned)
+ // . Size - Offset >= NeededSize (unsigned)
+ return Offset >= 0 && Size >= uint64_t(Offset) &&
+ Size - uint64_t(Offset) >= TypeSize / 8;
+}
projects / oota-llvm.git / blobdiff