diff --git a/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index f683bfb16c73fac461d1a558eb512982381179d9..25f1f022c40c9aac5926886811cf4ec22255490a 100644 (file)
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "asan"
-
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.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/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/InstVisitor.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/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/system_error.h"
+#include "llvm/Support/SwapByteOrder.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/SpecialCaseList.h"
#include <algorithm>
#include <string>
+#include <system_error>
using namespace llvm;
+#define DEBUG_TYPE "asan"
+
static const uint64_t kDefaultShadowScale = 3;
static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
+static const uint64_t kIOSShadowOffset32 = 1ULL << 30;
static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
-static const uint64_t kDefaultShort64bitShadowOffset = 0x7FFF8000; // < 2G.
+static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
-static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000;
+static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
+static const uint64_t kMIPS64_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 kMaxStackMallocSize = 1 << 16; // 64K
static const char *const kAsanModuleCtorName = "asan.module_ctor";
static const char *const kAsanModuleDtorName = "asan.module_dtor";
-static const int kAsanCtorAndCtorPriority = 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";
"__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 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 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 kSanCovGenPrefix = "__sancov_gen_";
static const char *const kAsanPoisonStackMemoryName =
"__asan_poison_stack_memory";
static const char *const kAsanUnpoisonStackMemoryName =
// 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.
// This flag may need to be replaced with -f[no]asan-stack.
static cl::opt<bool> ClStack("asan-stack",
cl::desc("Handle stack memory"), cl::Hidden, cl::init(true));
-// This flag may need to be replaced with -f[no]asan-use-after-return.
static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
- cl::desc("Check return-after-free"), cl::Hidden, cl::init(false));
+ 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));
-static cl::opt<bool> ClCoverage("asan-coverage",
- cl::desc("ASan coverage"), 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));
+ 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<std::string> ClBlacklistFile("asan-blacklist",
- cl::desc("File containing the list of objects to ignore "
- "during instrumentation"), cl::Hidden);
-
-// 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));
+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));
+static cl::opt<std::string> ClMemoryAccessCallbackPrefix(
+ "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));
// These flags allow to change the shadow mapping.
// The shadow mapping looks like
// Shadow = (Mem >> scale) + (1 << offset_log)
static cl::opt<int> ClMappingScale("asan-mapping-scale",
cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0));
-static cl::opt<int> ClMappingOffsetLog("asan-mapping-offset-log",
- cl::desc("offset of asan shadow mapping"), cl::Hidden, cl::init(-1));
-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));
// Optimization flags. Not user visible, used mostly for testing
// and benchmarking the tool.
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(false));
+
// Debug flags.
static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
cl::init(0));
STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
+STATISTIC(NumInstrumentedDynamicAllocas,
+ "Number of instrumented dynamic allocas");
STATISTIC(NumOptimizedAccessesToGlobalArray,
"Number of optimized accesses to global arrays");
STATISTIC(NumOptimizedAccessesToGlobalVar,
"Number of optimized accesses to global vars");
namespace {
-/// A set of dynamically initialized globals extracted from metadata.
-class SetOfDynamicallyInitializedGlobals {
+/// Frontend-provided metadata for source location.
+struct LocationMetadata {
+ StringRef Filename;
+ int LineNo;
+ int ColumnNo;
+
+ LocationMetadata() : Filename(), LineNo(0), ColumnNo(0) {}
+
+ bool empty() const { return Filename.empty(); }
+
+ void parse(MDNode *MDN) {
+ assert(MDN->getNumOperands() == 3);
+ MDString *MDFilename = cast<MDString>(MDN->getOperand(0));
+ Filename = MDFilename->getString();
+ LineNo =
+ mdconst::extract<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
+ ColumnNo =
+ mdconst::extract<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
+ }
+};
+
+/// Frontend-provided metadata for global variables.
+class GlobalsMetadata {
public:
- void Init(Module& M) {
- // Clang generates metadata identifying all dynamically initialized globals.
- NamedMDNode *DynamicGlobals =
- M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
- if (!DynamicGlobals)
+ struct Entry {
+ Entry()
+ : SourceLoc(), Name(), IsDynInit(false),
+ IsBlacklisted(false) {}
+ LocationMetadata SourceLoc;
+ StringRef Name;
+ bool IsDynInit;
+ bool IsBlacklisted;
+ };
+
+ GlobalsMetadata() : inited_(false) {}
+
+ void init(Module& M) {
+ assert(!inited_);
+ inited_ = true;
+ NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
+ if (!Globals)
return;
- for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
- MDNode *MDN = DynamicGlobals->getOperand(i);
- assert(MDN->getNumOperands() == 1);
- Value *VG = MDN->getOperand(0);
- // The optimizer may optimize away a global entirely, in which case we
- // cannot instrument access to it.
- if (!VG)
+ for (auto MDN : Globals->operands()) {
+ // Metadata node contains the global and the fields of "Entry".
+ assert(MDN->getNumOperands() == 5);
+ auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
+ // The optimizer may optimize away a global entirely.
+ if (!GV)
continue;
- DynInitGlobals.insert(cast<GlobalVariable>(VG));
+ // We can already have an entry for GV if it was merged with another
+ // global.
+ Entry &E = Entries[GV];
+ 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 =
+ mdconst::extract<ConstantInt>(MDN->getOperand(4));
+ E.IsBlacklisted |= IsBlacklisted->isOne();
}
}
- bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
+
+ /// Returns metadata entry for a given global.
+ Entry get(GlobalVariable *G) const {
+ auto Pos = Entries.find(G);
+ return (Pos != Entries.end()) ? Pos->second : Entry();
+ }
+
private:
- SmallSet<GlobalValue*, 32> DynInitGlobals;
+ bool inited_;
+ DenseMap<GlobalVariable*, Entry> Entries;
};
/// This struct defines the shadow mapping using the rule:
bool OrShadowOffset;
};
-static ShadowMapping getShadowMapping(const Module &M, int LongSize,
- bool ZeroBaseShadow) {
- llvm::Triple TargetTriple(M.getTargetTriple());
+static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize) {
bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
- bool IsMacOSX = TargetTriple.getOS() == llvm::Triple::MacOSX;
+ bool IsIOS = TargetTriple.isiOS();
+ 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;
bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
TargetTriple.getArch() == llvm::Triple::mipsel;
+ bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
+ TargetTriple.getArch() == llvm::Triple::mips64el;
+ bool IsWindows = TargetTriple.isOSWindows();
ShadowMapping Mapping;
- // OR-ing shadow offset if more efficient (at least on x86),
- // but on ppc64 we have to use add since the shadow offset is not neccesary
- // 1/8-th of the address space.
- Mapping.OrShadowOffset = !IsPPC64 && !ClShort64BitOffset;
-
- Mapping.Offset = (IsAndroid || ZeroBaseShadow) ? 0 :
- (LongSize == 32 ?
- (IsMIPS32 ? kMIPS32_ShadowOffset32 : kDefaultShadowOffset32) :
- IsPPC64 ? kPPC64_ShadowOffset64 : kDefaultShadowOffset64);
- if (!ZeroBaseShadow && ClShort64BitOffset && IsX86_64 && !IsMacOSX) {
- assert(LongSize == 64);
- Mapping.Offset = kDefaultShort64bitShadowOffset;
- }
- if (!ZeroBaseShadow && ClMappingOffsetLog >= 0) {
- // Zero offset log is the special case.
- Mapping.Offset = (ClMappingOffsetLog == 0) ? 0 : 1ULL << ClMappingOffsetLog;
+ if (LongSize == 32) {
+ if (IsAndroid)
+ Mapping.Offset = 0;
+ else if (IsMIPS32)
+ Mapping.Offset = kMIPS32_ShadowOffset32;
+ else if (IsFreeBSD)
+ Mapping.Offset = kFreeBSD_ShadowOffset32;
+ else if (IsIOS)
+ Mapping.Offset = kIOSShadowOffset32;
+ else if (IsWindows)
+ Mapping.Offset = kWindowsShadowOffset32;
+ else
+ Mapping.Offset = kDefaultShadowOffset32;
+ } else { // LongSize == 64
+ if (IsPPC64)
+ Mapping.Offset = kPPC64_ShadowOffset64;
+ else if (IsFreeBSD)
+ Mapping.Offset = kFreeBSD_ShadowOffset64;
+ else if (IsLinux && IsX86_64)
+ Mapping.Offset = kSmallX86_64ShadowOffset;
+ else if (IsMIPS64)
+ Mapping.Offset = kMIPS64_ShadowOffset64;
+ else
+ Mapping.Offset = kDefaultShadowOffset64;
}
Mapping.Scale = kDefaultShadowScale;
Mapping.Scale = ClMappingScale;
}
+ // OR-ing shadow offset if more efficient (at least on x86) if the offset
+ // is a power of two, but on ppc64 we have to use add since the shadow
+ // offset is not necessary 1/8-th of the address space.
+ Mapping.OrShadowOffset = !IsPPC64 && !(Mapping.Offset & (Mapping.Offset - 1));
+
return Mapping;
}
/// AddressSanitizer: instrument the code in module to find memory bugs.
struct AddressSanitizer : public FunctionPass {
- AddressSanitizer(bool CheckInitOrder = true,
- bool CheckUseAfterReturn = false,
- bool CheckLifetime = false,
- StringRef BlacklistFile = StringRef(),
- bool ZeroBaseShadow = false)
- : FunctionPass(ID),
- CheckInitOrder(CheckInitOrder || ClInitializers),
- CheckUseAfterReturn(CheckUseAfterReturn || ClUseAfterReturn),
- CheckLifetime(CheckLifetime || ClCheckLifetime),
- BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
- : BlacklistFile),
- ZeroBaseShadow(ZeroBaseShadow) {}
- virtual const char *getPassName() const {
+ AddressSanitizer() : FunctionPass(ID) {
+ initializeAddressSanitizerPass(*PassRegistry::getPassRegistry());
+ }
+ const char *getPassName() const override {
return "AddressSanitizerFunctionPass";
}
- void instrumentMop(Instruction *I);
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addRequired<DominatorTreeWrapperPass>();
+ }
+ void instrumentMop(Instruction *I, bool UseCalls);
+ void instrumentPointerComparisonOrSubtraction(Instruction *I);
void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
Value *Addr, uint32_t TypeSize, bool IsWrite,
- Value *SizeArgument);
+ Value *SizeArgument, bool UseCalls);
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);
+ void instrumentMemIntrinsic(MemIntrinsic *MI);
Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
- bool runOnFunction(Function &F);
+ bool runOnFunction(Function &F) override;
bool maybeInsertAsanInitAtFunctionEntry(Function &F);
- void emitShadowMapping(Module &M, IRBuilder<> &IRB) const;
- virtual bool doInitialization(Module &M);
+ bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid
+ DominatorTree &getDominatorTree() const { return *DT; }
+
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);
-
- bool CheckInitOrder;
- bool CheckUseAfterReturn;
- bool CheckLifetime;
- SmallString<64> BlacklistFile;
- bool ZeroBaseShadow;
LLVMContext *C;
- DataLayout *TD;
+ const DataLayout *DL;
+ Triple TargetTriple;
int LongSize;
Type *IntptrTy;
ShadowMapping Mapping;
+ DominatorTree *DT;
Function *AsanCtorFunction;
Function *AsanInitFunction;
Function *AsanHandleNoReturnFunc;
- Function *AsanCovFunction;
- OwningPtr<SpecialCaseList> BL;
+ 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];
+ Function *AsanErrorCallbackSized[2],
+ *AsanMemoryAccessCallbackSized[2];
+ Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
InlineAsm *EmptyAsm;
- SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
+ GlobalsMetadata GlobalsMD;
friend struct FunctionStackPoisoner;
};
class AddressSanitizerModule : public ModulePass {
public:
- AddressSanitizerModule(bool CheckInitOrder = true,
- StringRef BlacklistFile = StringRef(),
- bool ZeroBaseShadow = false)
- : ModulePass(ID),
- CheckInitOrder(CheckInitOrder || ClInitializers),
- BlacklistFile(BlacklistFile.empty() ? ClBlacklistFile
- : BlacklistFile),
- ZeroBaseShadow(ZeroBaseShadow) {}
- bool runOnModule(Module &M);
+ AddressSanitizerModule() : ModulePass(ID) {}
+ bool runOnModule(Module &M) override;
static char ID; // Pass identification, replacement for typeid
- virtual const char *getPassName() const {
+ const char *getPassName() const override {
return "AddressSanitizerModule";
}
private:
void initializeCallbacks(Module &M);
+ bool InstrumentGlobals(IRBuilder<> &IRB, Module &M);
bool ShouldInstrumentGlobal(GlobalVariable *G);
+ void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName);
void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
size_t MinRedzoneSizeForGlobal() const {
return RedzoneSizeForScale(Mapping.Scale);
}
- bool CheckInitOrder;
- SmallString<64> BlacklistFile;
- bool ZeroBaseShadow;
-
- OwningPtr<SpecialCaseList> BL;
- SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
+ GlobalsMetadata GlobalsMD;
Type *IntptrTy;
LLVMContext *C;
- DataLayout *TD;
+ const DataLayout *DL;
+ Triple TargetTriple;
ShadowMapping Mapping;
Function *AsanPoisonGlobals;
Function *AsanUnpoisonGlobals;
};
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;
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)),
- Mapping(ASan.Mapping),
- StackAlignment(1 << Mapping.Scale) {}
+ : 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), HasNonEmptyInlineAsm(false),
+ EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
bool runOnFunction() {
if (!ClStack) return false;
// Collect alloca, ret, lifetime instructions etc.
- for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
- DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
- BasicBlock *BB = *DI;
+ 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();
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) {
+ return ASan.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;
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
/// errors.
void visitIntrinsicInst(IntrinsicInst &II) {
- if (!ASan.CheckLifetime) return;
+ if (!ClCheckLifetime) return;
Intrinsic::ID ID = II.getIntrinsicID();
if (ID != Intrinsic::lifetime_start &&
ID != Intrinsic::lifetime_end)
AllocaPoisonCallVec.push_back(APC);
}
+ void visitCallInst(CallInst &CI) {
+ HasNonEmptyInlineAsm |=
+ CI.isInlineAsm() && !CI.isIdenticalTo(EmptyInlineAsm.get());
+ }
+
// ---------------------- Helpers.
void initializeCallbacks(Module &M);
+ bool doesDominateAllExits(const Instruction *I) const {
+ for (auto Ret : RetVec) {
+ if (!ASan.getDominatorTree().dominates(I, Ret))
+ return false;
+ }
+ return true;
+ }
+
+ bool isDynamicAlloca(AllocaInst &AI) const {
+ return AI.isArrayAllocation() || !AI.isStaticAlloca();
+ }
+
// Check if we want (and can) handle this alloca.
bool isInterestingAlloca(AllocaInst &AI) const {
- return (!AI.isArrayAllocation() && AI.isStaticAlloca() &&
- AI.getAllocatedType()->isSized() &&
+ return (AI.getAllocatedType()->isSized() &&
// alloca() may be called with 0 size, ignore it.
getAllocaSizeInBytes(&AI) > 0);
}
uint64_t getAllocaSizeInBytes(AllocaInst *AI) const {
Type *Ty = AI->getAllocatedType();
- uint64_t SizeInBytes = ASan.TD->getTypeAllocSize(Ty);
+ uint64_t SizeInBytes = ASan.DL->getTypeAllocSize(Ty);
return SizeInBytes;
}
/// Finds alloca where the value comes from.
AllocaInst *findAllocaForValue(Value *V);
- void poisonRedZones(const ArrayRef<uint8_t> ShadowBytes, IRBuilder<> &IRB,
+ void poisonRedZones(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);
+ 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",
+INITIALIZE_PASS_BEGIN(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, bool ZeroBaseShadow) {
- return new AddressSanitizer(CheckInitOrder, CheckUseAfterReturn,
- CheckLifetime, BlacklistFile, ZeroBaseShadow);
+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",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs."
"ModulePass", false, false)
-ModulePass *llvm::createAddressSanitizerModulePass(
- bool CheckInitOrder, StringRef BlacklistFile, bool ZeroBaseShadow) {
- return new AddressSanitizerModule(CheckInitOrder, BlacklistFile,
- ZeroBaseShadow);
+ModulePass *llvm::createAddressSanitizerModulePass() {
+ return new AddressSanitizerModule();
}
static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
}
// \brief Create a constant for Str so that we can pass it to the run-time lib.
-static GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str) {
+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::InternalLinkage, StrConst,
- kAsanGenPrefix);
- GV->setUnnamedAddr(true); // Ok to merge these.
+ // 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);
GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
return GV;
}
+/// \brief Create a global describing a source location.
+static GlobalVariable *createPrivateGlobalForSourceLoc(Module &M,
+ LocationMetadata MD) {
+ Constant *LocData[] = {
+ createPrivateGlobalForString(M, MD.Filename, true),
+ ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.LineNo),
+ ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.ColumnNo),
+ };
+ auto LocStruct = ConstantStruct::getAnon(LocData);
+ auto GV = new GlobalVariable(M, LocStruct->getType(), true,
+ GlobalValue::PrivateLinkage, LocStruct,
+ kAsanGenPrefix);
+ GV->setUnnamedAddr(true);
+ return GV;
+}
+
static bool GlobalWasGeneratedByAsan(GlobalVariable *G) {
- return G->getName().find(kAsanGenPrefix) == 0;
+ return G->getName().find(kAsanGenPrefix) == 0 ||
+ G->getName().find(kSanCovGenPrefix) == 0;
}
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
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);
- // Check the first byte.
- instrumentAddress(OrigIns, InsertBefore, Addr, 8, IsWrite, Size);
- // Check the last byte.
- 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);
-}
-
// Instrument memset/memmove/memcpy
-bool AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
- Value *Dst = MI->getDest();
- MemTransferInst *MemTran = dyn_cast<MemTransferInst>(MI);
- Value *Src = MemTran ? MemTran->getSource() : 0;
- Value *Length = MI->getLength();
-
- Constant *ConstLength = dyn_cast<Constant>(Length);
- Instruction *InsertBefore = MI;
- if (ConstLength) {
- if (ConstLength->isNullValue()) return false;
- } else {
- // The size is not a constant so it could be zero -- check at run-time.
- IRBuilder<> IRB(InsertBefore);
-
- Value *Cmp = IRB.CreateICmpNE(Length,
- Constant::getNullValue(Length->getType()));
- InsertBefore = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
+void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
+ IRBuilder<> IRB(MI);
+ if (isa<MemTransferInst>(MI)) {
+ IRB.CreateCall3(
+ isa<MemMoveInst>(MI) ? AsanMemmove : AsanMemcpy,
+ IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
+ IRB.CreatePointerCast(MI->getOperand(1), IRB.getInt8PtrTy()),
+ IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false));
+ } else if (isa<MemSetInst>(MI)) {
+ IRB.CreateCall3(
+ AsanMemset,
+ IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
+ IRB.CreateIntCast(MI->getOperand(1), IRB.getInt32Ty(), false),
+ IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false));
}
-
- instrumentMemIntrinsicParam(MI, Dst, Length, InsertBefore, true);
- if (Src)
- instrumentMemIntrinsicParam(MI, Src, Length, InsertBefore, false);
- return true;
+ MI->eraseFromParent();
}
// If I is an interesting memory access, return the PointerOperand
-// and set IsWrite. Otherwise return NULL.
-static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
+// and set IsWrite/Alignment. Otherwise return nullptr.
+static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
+ unsigned *Alignment) {
+ // Skip memory accesses inserted by another instrumentation.
+ if (I->getMetadata("nosanitize"))
+ return nullptr;
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- if (!ClInstrumentReads) return NULL;
+ if (!ClInstrumentReads) return nullptr;
*IsWrite = false;
+ *Alignment = LI->getAlignment();
return LI->getPointerOperand();
}
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
- if (!ClInstrumentWrites) return NULL;
+ if (!ClInstrumentWrites) return nullptr;
*IsWrite = true;
+ *Alignment = SI->getAlignment();
return SI->getPointerOperand();
}
if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
- if (!ClInstrumentAtomics) return NULL;
+ if (!ClInstrumentAtomics) return nullptr;
*IsWrite = true;
+ *Alignment = 0;
return RMW->getPointerOperand();
}
if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
- if (!ClInstrumentAtomics) return NULL;
+ if (!ClInstrumentAtomics) return nullptr;
*IsWrite = true;
+ *Alignment = 0;
return XCHG->getPointerOperand();
}
- return NULL;
+ return nullptr;
+}
+
+static bool isPointerOperand(Value *V) {
+ return V->getType()->isPointerTy() || isa<PtrToIntInst>(V);
+}
+
+// This is a rough heuristic; it may cause both false positives and
+// false negatives. The proper implementation requires cooperation with
+// the frontend.
+static bool isInterestingPointerComparisonOrSubtraction(Instruction *I) {
+ if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
+ if (!Cmp->isRelational())
+ return false;
+ } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
+ if (BO->getOpcode() != Instruction::Sub)
+ return false;
+ } else {
+ return false;
+ }
+ if (!isPointerOperand(I->getOperand(0)) ||
+ !isPointerOperand(I->getOperand(1)))
+ return false;
+ return true;
}
bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
// If a global variable does not have dynamic initialization we don't
// have to instrument it. However, if a global does not have initializer
// at all, we assume it has dynamic initializer (in other TU).
- return G->hasInitializer() && !DynamicallyInitializedGlobals.Contains(G);
+ return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
}
-void AddressSanitizer::instrumentMop(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)};
+ for (int i = 0; i < 2; i++) {
+ if (Param[i]->getType()->isPointerTy())
+ Param[i] = IRB.CreatePointerCast(Param[i], IntptrTy);
+ }
+ IRB.CreateCall2(F, Param[0], Param[1]);
+}
+
+void AddressSanitizer::instrumentMop(Instruction *I, bool UseCalls) {
bool IsWrite = false;
- Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
+ unsigned Alignment = 0;
+ Value *Addr = isInterestingMemoryAccess(I, &IsWrite, &Alignment);
assert(Addr);
if (ClOpt && ClOptGlobals) {
if (GlobalVariable *G = dyn_cast<GlobalVariable>(Addr)) {
// If initialization order checking is disabled, a simple access to a
// dynamically initialized global is always valid.
- if (!CheckInitOrder || GlobalIsLinkerInitialized(G)) {
+ if (!ClInitializers || GlobalIsLinkerInitialized(G)) {
NumOptimizedAccessesToGlobalVar++;
return;
}
Type *OrigTy = cast<PointerType>(OrigPtrTy)->getElementType();
assert(OrigTy->isSized());
- uint32_t TypeSize = TD->getTypeStoreSizeInBits(OrigTy);
+ uint32_t TypeSize = DL->getTypeStoreSizeInBits(OrigTy);
assert((TypeSize % 8) == 0);
else
NumInstrumentedReads++;
- // Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check.
- if (TypeSize == 8 || TypeSize == 16 ||
- TypeSize == 32 || TypeSize == 64 || TypeSize == 128)
- return instrumentAddress(I, I, Addr, TypeSize, IsWrite, 0);
- // Instrument unusual size (but still multiple of 8).
+ unsigned Granularity = 1 << Mapping.Scale;
+ // Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check
+ // if the data is properly aligned.
+ 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 *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);
+ 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);
+ }
}
// Validate the result of Module::getOrInsertFunction called for an interface
}
void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
- Instruction *InsertBefore,
- Value *Addr, uint32_t TypeSize,
- bool IsWrite, Value *SizeArgument) {
+ Instruction *InsertBefore, Value *Addr,
+ uint32_t TypeSize, bool IsWrite,
+ Value *SizeArgument, bool UseCalls) {
IRBuilder<> IRB(InsertBefore);
Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
+ size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
+
+ if (UseCalls) {
+ IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][AccessSizeIndex],
+ AddrLong);
+ return;
+ }
Type *ShadowTy = IntegerType::get(
*C, std::max(8U, TypeSize >> Mapping.Scale));
IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
- size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
size_t Granularity = 1 << Mapping.Scale;
- TerminatorInst *CrashTerm = 0;
+ TerminatorInst *CrashTerm = nullptr;
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(cast<Instruction>(Cmp), false);
+ SplitBlockAndInsertIfThen(Cmp, InsertBefore, false,
+ MDBuilder(*C).createBranchWeights(1, 100000));
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
ReplaceInstWithInst(CheckTerm, NewTerm);
} else {
- CrashTerm = SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), true);
+ CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, true);
}
Instruction *Crash = generateCrashCode(
Crash->setDebugLoc(OrigIns->getDebugLoc());
}
-void AddressSanitizerModule::createInitializerPoisonCalls(
- Module &M, GlobalValue *ModuleName) {
- // We do all of our poisoning and unpoisoning within _GLOBAL__I_a.
- Function *GlobalInit = M.getFunction("_GLOBAL__I_a");
- // If that function is not present, this TU contains no globals, or they have
- // all been optimized away
- if (!GlobalInit)
- return;
-
+void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit,
+ GlobalValue *ModuleName) {
// Set up the arguments to our poison/unpoison functions.
- IRBuilder<> IRB(GlobalInit->begin()->getFirstInsertionPt());
+ IRBuilder<> IRB(GlobalInit.begin()->getFirstInsertionPt());
// Add a call to poison all external globals before the given function starts.
Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr);
// Add calls to unpoison all globals before each return instruction.
- for (Function::iterator I = GlobalInit->begin(), E = GlobalInit->end();
- I != E; ++I) {
- if (ReturnInst *RI = dyn_cast<ReturnInst>(I->getTerminator())) {
+ for (auto &BB : GlobalInit.getBasicBlockList())
+ if (ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator()))
CallInst::Create(AsanUnpoisonGlobals, "", RI);
+}
+
+void AddressSanitizerModule::createInitializerPoisonCalls(
+ Module &M, GlobalValue *ModuleName) {
+ GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
+
+ ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
+ for (Use &OP : CA->operands()) {
+ 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 (F->getName() == kAsanModuleCtorName) continue;
+ ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
+ // Don't instrument CTORs that will run before asan.module_ctor.
+ if (Priority->getLimitedValue() <= kAsanCtorAndDtorPriority) continue;
+ poisonOneInitializer(*F, ModuleName);
}
}
}
Type *Ty = cast<PointerType>(G->getType())->getElementType();
DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
- if (BL->isIn(*G)) return false;
+ if (GlobalsMD.get(G).IsBlacklisted) return false;
if (!Ty->isSized()) return false;
if (!G->hasInitializer()) return false;
if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
// Touch only those globals that will not be defined in other modules.
- // Don't handle ODR type linkages since other modules may be built w/o asan.
+ // Don't handle ODR linkage types and COMDATs since other modules may be built
+ // without ASan.
if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
G->getLinkage() != GlobalVariable::PrivateLinkage &&
G->getLinkage() != GlobalVariable::InternalLinkage)
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.
// For now, just ignore this Global if the alignment is large.
if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
- // Ignore all the globals with the names starting with "\01L_OBJC_".
- // Many of those are put into the .cstring section. The linker compresses
- // that section by removing the spare \0s after the string terminator, so
- // our redzones get broken.
- if ((G->getName().find("\01L_OBJC_") == 0) ||
- (G->getName().find("\01l_OBJC_") == 0)) {
- DEBUG(dbgs() << "Ignoring \\01L_OBJC_* global: " << *G);
- return false;
- }
-
if (G->hasSection()) {
StringRef Section(G->getSection());
- // Ignore the globals from the __OBJC section. The ObjC runtime assumes
- // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
- // them.
- if ((Section.find("__OBJC,") == 0) ||
- (Section.find("__DATA, __objc_") == 0)) {
- DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G);
- return false;
+
+ 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;
+ }
}
- // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
- // Constant CFString instances are compiled in the following way:
- // -- the string buffer is emitted into
- // __TEXT,__cstring,cstring_literals
- // -- the constant NSConstantString structure referencing that buffer
- // is placed into __DATA,__cfstring
- // Therefore there's no point in placing redzones into __DATA,__cfstring.
- // Moreover, it causes the linker to crash on OS X 10.7
- if (Section.find("__DATA,__cfstring") == 0) {
- DEBUG(dbgs() << "Ignoring CFString: " << *G);
+
+ // Callbacks put into the CRT initializer/terminator sections
+ // should not be instrumented.
+ // See https://code.google.com/p/address-sanitizer/issues/detail?id=305
+ // and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
+ if (Section.startswith(".CRT")) {
+ DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
return false;
}
+
+ // Globals from llvm.metadata aren't emitted, do not instrument them.
+ if (Section == "llvm.metadata") return false;
}
return true;
IRBuilder<> IRB(*C);
// Declare our poisoning and unpoisoning functions.
AsanPoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, NULL));
+ kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy, nullptr));
AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
AsanUnpoisonGlobals = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanUnpoisonGlobalsName, IRB.getVoidTy(), NULL));
+ kAsanUnpoisonGlobalsName, IRB.getVoidTy(), nullptr));
AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
// Declare functions that register/unregister globals.
AsanRegisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanRegisterGlobalsName, IRB.getVoidTy(),
- IntptrTy, IntptrTy, NULL));
+ IntptrTy, IntptrTy, nullptr));
AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
AsanUnregisterGlobals = checkInterfaceFunction(M.getOrInsertFunction(
kAsanUnregisterGlobalsName,
- IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
}
// This function replaces all global variables with new variables that have
// trailing redzones. It also creates a function that poisons
// redzones and inserts this function into llvm.global_ctors.
-bool 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, ZeroBaseShadow);
- initializeCallbacks(M);
- DynamicallyInitializedGlobals.Init(M);
+bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M) {
+ GlobalsMD.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);
+ for (auto &G : M.globals()) {
+ if (ShouldInstrumentGlobal(&G))
+ GlobalsToChange.push_back(&G);
}
size_t n = GlobalsToChange.size();
// const char *name;
// const char *module_name;
// size_t has_dynamic_init;
+ // void *source_location;
// We initialize an array of such structures and pass it to a run-time call.
- StructType *GlobalStructTy = StructType::get(IntptrTy, IntptrTy,
- IntptrTy, IntptrTy,
- IntptrTy, IntptrTy, NULL);
+ StructType *GlobalStructTy =
+ StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
+ IntptrTy, IntptrTy, nullptr);
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());
// We shouldn't merge same module names, as this string serves as unique
// module ID in runtime.
- ModuleName->setUnnamedAddr(false);
+ GlobalVariable *ModuleName = createPrivateGlobalForString(
+ M, M.getModuleIdentifier(), /*AllowMerging*/false);
for (size_t i = 0; i < n; i++) {
static const uint64_t kMaxGlobalRedzone = 1 << 18;
GlobalVariable *G = GlobalsToChange[i];
+
+ auto MD = GlobalsMD.get(G);
+ // Create string holding the global name (use global name from metadata
+ // if it's available, otherwise just write the name of global variable).
+ GlobalVariable *Name = createPrivateGlobalForString(
+ M, MD.Name.empty() ? G->getName() : MD.Name,
+ /*AllowMerging*/ true);
+
PointerType *PtrTy = cast<PointerType>(G->getType());
Type *Ty = PtrTy->getElementType();
- uint64_t SizeInBytes = TD->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.
RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
- // Determine whether this global should be poisoned in initialization.
- bool GlobalHasDynamicInitializer =
- DynamicallyInitializedGlobals.Contains(G);
- // Don't check initialization order if this global is blacklisted.
- GlobalHasDynamicInitializer &= !BL->isIn(*G, "init");
- StructType *NewTy = StructType::get(Ty, RightRedZoneTy, NULL);
+ StructType *NewTy = StructType::get(Ty, RightRedZoneTy, nullptr);
Constant *NewInitializer = ConstantStruct::get(
NewTy, G->getInitializer(),
- Constant::getNullValue(RightRedZoneTy), NULL);
-
- GlobalVariable *Name = createPrivateGlobalForString(M, G->getName());
+ Constant::getNullValue(RightRedZoneTy), nullptr);
// Create a new global variable with enough space for a redzone.
GlobalValue::LinkageTypes Linkage = G->getLinkage();
NewGlobal->takeName(G);
G->eraseFromParent();
+ Constant *SourceLoc;
+ if (!MD.SourceLoc.empty()) {
+ auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc);
+ SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy);
+ } else {
+ SourceLoc = ConstantInt::get(IntptrTy, 0);
+ }
+
Initializers[i] = ConstantStruct::get(
- GlobalStructTy,
- ConstantExpr::getPointerCast(NewGlobal, IntptrTy),
+ 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);
+ ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, nullptr);
- // Populate the first and last globals declared in this TU.
- if (CheckInitOrder && GlobalHasDynamicInitializer)
+ if (ClInitializers && MD.IsDynInit)
HasDynamicallyInitializedGlobals = true;
DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
ConstantArray::get(ArrayOfGlobalStructTy, Initializers), "");
// Create calls for poisoning before initializers run and unpoisoning after.
- if (CheckInitOrder && HasDynamicallyInitializedGlobals)
+ if (HasDynamicallyInitializedGlobals)
createInitializerPoisonCalls(M, ModuleName);
IRB.CreateCall2(AsanRegisterGlobals,
IRB.CreatePointerCast(AllGlobals, IntptrTy),
IRB_Dtor.CreateCall2(AsanUnregisterGlobals,
IRB.CreatePointerCast(AllGlobals, IntptrTy),
ConstantInt::get(IntptrTy, n));
- appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndCtorPriority);
+ appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
DEBUG(dbgs() << M);
return true;
}
+bool AddressSanitizerModule::runOnModule(Module &M) {
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ if (!DLP)
+ return false;
+ DL = &DLP->getDataLayout();
+ C = &(M.getContext());
+ int LongSize = DL->getPointerSizeInBits();
+ IntptrTy = Type::getIntNTy(*C, LongSize);
+ TargetTriple = Triple(M.getTargetTriple());
+ Mapping = getShadowMapping(TargetTriple, LongSize);
+ initializeCallbacks(M);
+
+ bool Changed = false;
+
+ Function *CtorFunc = M.getFunction(kAsanModuleCtorName);
+ assert(CtorFunc);
+ IRBuilder<> IRB(CtorFunc->getEntryBlock().getTerminator());
+
+ if (ClGlobals)
+ Changed |= InstrumentGlobals(IRB, M);
+
+ return Changed;
+}
+
void AddressSanitizer::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
// Create __asan_report* callbacks.
for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
AccessSizeIndex++) {
// IsWrite and TypeSize are encoded in the function name.
- std::string FunctionName = std::string(kAsanReportErrorTemplate) +
+ std::string Suffix =
(AccessIsWrite ? "store" : "load") + itostr(1 << AccessSizeIndex);
- // If we are merging crash callbacks, they have two parameters.
AsanErrorCallback[AccessIsWrite][AccessSizeIndex] =
- checkInterfaceFunction(M.getOrInsertFunction(
- FunctionName, IRB.getVoidTy(), IntptrTy, NULL));
+ checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanReportErrorTemplate + Suffix,
+ IRB.getVoidTy(), IntptrTy, nullptr));
+ AsanMemoryAccessCallback[AccessIsWrite][AccessSizeIndex] =
+ checkInterfaceFunction(
+ M.getOrInsertFunction(ClMemoryAccessCallbackPrefix + Suffix,
+ IRB.getVoidTy(), IntptrTy, nullptr));
}
}
AsanErrorCallbackSized[0] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ kAsanReportLoadN, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
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(), IntptrTy, NULL));
+ 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(),
+ IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
+ AsanMemcpy = checkInterfaceFunction(M.getOrInsertFunction(
+ ClMemoryAccessCallbackPrefix + "memcpy", IRB.getInt8PtrTy(),
+ IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy, nullptr));
+ AsanMemset = checkInterfaceFunction(M.getOrInsertFunction(
+ ClMemoryAccessCallbackPrefix + "memset", IRB.getInt8PtrTy(),
+ IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy, nullptr));
+
+ AsanHandleNoReturnFunc = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), nullptr));
+
+ AsanPtrCmpFunction = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
+ AsanPtrSubFunction = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy, nullptr));
// We insert an empty inline asm after __asan_report* to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
/*hasSideEffects=*/true);
}
-void AddressSanitizer::emitShadowMapping(Module &M, IRBuilder<> &IRB) const {
- // Tell the values of mapping offset and scale to the run-time.
- GlobalValue *asan_mapping_offset =
- new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
- ConstantInt::get(IntptrTy, Mapping.Offset),
- kAsanMappingOffsetName);
- // Read the global, otherwise it may be optimized away.
- IRB.CreateLoad(asan_mapping_offset, true);
-
- GlobalValue *asan_mapping_scale =
- new GlobalVariable(M, IntptrTy, true, GlobalValue::LinkOnceODRLinkage,
- ConstantInt::get(IntptrTy, Mapping.Scale),
- kAsanMappingScaleName);
- // Read the global, otherwise it may be optimized away.
- IRB.CreateLoad(asan_mapping_scale, true);
-}
-
// virtual
bool AddressSanitizer::doInitialization(Module &M) {
// Initialize the private fields. No one has accessed them before.
- TD = getAnalysisIfAvailable<DataLayout>();
+ DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+ if (!DLP)
+ report_fatal_error("data layout missing");
+ DL = &DLP->getDataLayout();
- if (!TD)
- return false;
- BL.reset(SpecialCaseList::createOrDie(BlacklistFile));
- DynamicallyInitializedGlobals.Init(M);
+ GlobalsMD.init(M);
C = &(M.getContext());
- LongSize = TD->getPointerSizeInBits();
+ LongSize = DL->getPointerSizeInBits();
IntptrTy = Type::getIntNTy(*C, LongSize);
+ TargetTriple = Triple(M.getTargetTriple());
AsanCtorFunction = Function::Create(
FunctionType::get(Type::getVoidTy(*C), false),
// call __asan_init in the module ctor.
IRBuilder<> IRB(ReturnInst::Create(*C, AsanCtorBB));
AsanInitFunction = checkInterfaceFunction(
- M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), NULL));
+ M.getOrInsertFunction(kAsanInitName, IRB.getVoidTy(), nullptr));
AsanInitFunction->setLinkage(Function::ExternalLinkage);
IRB.CreateCall(AsanInitFunction);
- Mapping = getShadowMapping(M, LongSize, ZeroBaseShadow);
- emitShadowMapping(M, IRB);
+ Mapping = getShadowMapping(TargetTriple, LongSize);
- appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndCtorPriority);
+ appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
return true;
}
return false;
}
-// Poor man's coverage that works with ASan.
-// We create a Guard boolean variable with the same linkage
-// as the function and inject this code into the entry block:
-// if (*Guard) {
-// __sanitizer_cov(&F);
-// *Guard = 1;
-// }
-// The accesses to Guard are atomic. The rest of the logic is
-// in __sanitizer_cov (it's fine to call it more than once).
-//
-// This coverage implementation provides very limited data:
-// it only tells if a given function was ever executed.
-// No counters, no per-basic-block or per-edge data.
-// But for many use cases this is what we need and the added slowdown
-// is negligible. This simple implementation will probably be obsoleted
-// by the upcoming Clang-based coverage implementation.
-// By having it here and now we hope to
-// a) get the functionality to users earlier and
-// b) collect usage statistics to help improve Clang coverage design.
-bool AddressSanitizer::InjectCoverage(Function &F) {
- if (!ClCoverage) return false;
-
- // Skip static allocas at the top of the entry block so they don't become
- // dynamic when we split the block. If we used our optimized stack layout,
- // then there will only be one alloca and it will come first.
- BasicBlock &Entry = F.getEntryBlock();
- BasicBlock::iterator IP = Entry.getFirstInsertionPt(), BE = Entry.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(cast<Instruction>(Cmp), false);
- IRB.SetInsertPoint(Ins);
- // We pass &F to __sanitizer_cov. We could avoid this and rely on
- // GET_CALLER_PC, but having the PC of the first instruction is just nice.
- IRB.CreateCall(AsanCovFunction, IRB.CreatePointerCast(&F, IntptrTy));
- StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
- Store->setAtomic(Monotonic);
- Store->setAlignment(1);
- 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());
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+
// If needed, insert __asan_init before checking for SanitizeAddress attr.
maybeInsertAsanInitAtFunctionEntry(F);
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;
// Fill the set of memory operations to instrument.
- for (Function::iterator FI = F.begin(), FE = F.end();
- FI != FE; ++FI) {
+ for (auto &BB : F) {
+ AllBlocks.push_back(&BB);
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)) {
+ for (auto &Inst : BB) {
+ if (LooksLikeCodeInBug11395(&Inst)) return false;
+ if (Value *Addr =
+ isInterestingMemoryAccess(&Inst, &IsWrite, &Alignment)) {
if (ClOpt && ClOptSameTemp) {
- if (!TempsToInstrument.insert(Addr))
+ if (!TempsToInstrument.insert(Addr).second)
continue; // We've seen this temp in the current BB.
}
- } else if (isa<MemIntrinsic>(BI) && ClMemIntrin) {
+ } else if (ClInvalidPointerPairs &&
+ isInterestingPointerComparisonOrSubtraction(&Inst)) {
+ PointerComparisonsOrSubtracts.push_back(&Inst);
+ continue;
+ } else if (isa<MemIntrinsic>(Inst)) {
// ok, take it.
} else {
- if (isa<AllocaInst>(BI))
+ if (isa<AllocaInst>(Inst))
NumAllocas++;
- CallSite CS(BI);
+ CallSite CS(&Inst);
if (CS) {
// A call inside BB.
TempsToInstrument.clear();
}
continue;
}
- ToInstrument.push_back(BI);
+ ToInstrument.push_back(&Inst);
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);
- }
+ bool UseCalls = false;
+ if (ClInstrumentationWithCallsThreshold >= 0 &&
+ ToInstrument.size() > (unsigned)ClInstrumentationWithCallsThreshold)
+ UseCalls = true;
// Instrument.
int NumInstrumented = 0;
- for (size_t i = 0, n = ToInstrument.size(); i != n; i++) {
- Instruction *Inst = ToInstrument[i];
+ for (auto Inst : ToInstrument) {
if (ClDebugMin < 0 || ClDebugMax < 0 ||
(NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
- if (isInterestingMemoryAccess(Inst, &IsWrite))
- instrumentMop(Inst);
+ if (isInterestingMemoryAccess(Inst, &IsWrite, &Alignment))
+ instrumentMop(Inst, UseCalls);
else
instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
}
// We must unpoison the stack before every NoReturn call (throw, _exit, etc).
// See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
- for (size_t i = 0, n = NoReturnCalls.size(); i != n; i++) {
- Instruction *CI = NoReturnCalls[i];
+ for (auto CI : NoReturnCalls) {
IRBuilder<> IRB(CI);
IRB.CreateCall(AsanHandleNoReturnFunc);
}
- bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
+ for (auto Inst : PointerComparisonsOrSubtracts) {
+ instrumentPointerComparisonOrSubtraction(Inst);
+ NumInstrumented++;
+ }
- if (InjectCoverage(F))
- res = true;
+ bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
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, NULL));
- AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
- IntptrTy, IntptrTy, NULL));
+ 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, NULL));
- AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanUnpoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+ AsanPoisonStackMemoryFunc = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanPoisonStackMemoryName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, nullptr));
+ AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanUnpoisonStackMemoryName, IRB.getVoidTy(),
+ IntptrTy, IntptrTy, nullptr));
}
void
-FunctionStackPoisoner::poisonRedZones(const ArrayRef<uint8_t> ShadowBytes,
+FunctionStackPoisoner::poisonRedZones(ArrayRef<uint8_t> ShadowBytes,
IRBuilder<> &IRB, Value *ShadowBase,
bool DoPoison) {
size_t n = ShadowBytes.size();
- size_t LargeStoreSize = ASan.LongSize / 8;
- size_t i;
- for (i = 0; i + LargeStoreSize - 1 < n; i += LargeStoreSize) {
- uint64_t Val = 0;
- for (size_t j = 0; j < LargeStoreSize; j++) {
- if (ASan.TD->isLittleEndian())
- Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
- else
- Val = (Val << 8) | ShadowBytes[i + j];
+ size_t i = 0;
+ // We need to (un)poison n bytes of stack shadow. Poison as many as we can
+ // using 64-bit stores (if we are on 64-bit arch), then poison the rest
+ // with 32-bit stores, then with 16-byte stores, then with 8-byte stores.
+ 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.DL->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()));
}
- if (!Val) continue;
- Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
- Value *Poison = ConstantInt::get(IntptrTy, DoPoison ? Val : 0);
- IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, IntptrPtrTy));
- }
- for (; i < n; i++) {
- uint8_t Val = ShadowBytes[i];
- if (!Val) continue;
- Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
- Value *Poison = ConstantInt::get(IRB.getInt8Ty(), DoPoison ? Val : 0);
- IRB.CreateStore(Poison, IRB.CreateIntToPtr(Ptr, IRB.getInt8PtrTy()));
}
}
}
}
+static DebugLoc getFunctionEntryDebugLocation(Function &F) {
+ for (const auto &Inst : F.getEntryBlock())
+ 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);
+
+ 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 (size_t i = 0, n = AllocaVec.size(); i < n; i++) {
- AllocaInst *AI = AllocaVec[i];
+ for (AllocaInst *AI : AllocaVec) {
ASanStackVariableDescription D = { AI->getName().data(),
getAllocaSizeInBytes(AI),
AI->getAlignment(), AI, 0};
DEBUG(dbgs() << L.DescriptionString << " --- " << L.FrameSize << "\n");
uint64_t LocalStackSize = L.FrameSize;
bool DoStackMalloc =
- ASan.CheckUseAfterReturn && LocalStackSize <= kMaxStackMallocSize;
+ 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);
- 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()));
+ Value *UARIsEnabled =
+ IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUAR),
+ Constant::getNullValue(IRB.getInt32Ty()));
Instruction *Term =
- SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
- BasicBlock *CmpBlock = cast<Instruction>(Cmp)->getParent();
+ SplitBlockAndInsertIfThen(UARIsEnabled, InsBefore, false);
IRBuilder<> IRBIf(Term);
- LocalStackBase = IRBIf.CreateCall2(
- AsanStackMallocFunc[StackMallocIdx],
- ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
- BasicBlock *SetBlock = cast<Instruction>(LocalStackBase)->getParent();
+ IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
+ StackMallocIdx = StackMallocSizeClass(LocalStackSize);
+ assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
+ Value *FakeStackValue =
+ IRBIf.CreateCall(AsanStackMallocFunc[StackMallocIdx],
+ ConstantInt::get(IntptrTy, LocalStackSize));
+ IRB.SetInsertPoint(InsBefore);
+ IRB.SetCurrentDebugLocation(EntryDebugLocation);
+ 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);
- PHINode *Phi = IRB.CreatePHI(IntptrTy, 2);
- Phi->addIncoming(OrigStackBase, CmpBlock);
- Phi->addIncoming(LocalStackBase, SetBlock);
- LocalStackBase = Phi;
+ 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.
bool HavePoisonedAllocas = false;
- for (size_t i = 0, n = AllocaPoisonCallVec.size(); i < n; i++) {
- const AllocaPoisonCall &APC = AllocaPoisonCallVec[i];
+ for (const auto &APC : AllocaPoisonCallVec) {
assert(APC.InsBefore);
assert(APC.AI);
IRBuilder<> IRB(APC.InsBefore);
}
// Replace Alloca instructions with base+offset.
- for (size_t i = 0, n = SVD.size(); i < n; i++) {
- AllocaInst *AI = SVD[i].AI;
+ for (const auto &Desc : SVD) {
+ AllocaInst *AI = Desc.AI;
Value *NewAllocaPtr = IRB.CreateIntToPtr(
- IRB.CreateAdd(LocalStackBase,
- ConstantInt::get(IntptrTy, SVD[i].Offset)),
+ IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
AI->getType());
replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB);
AI->replaceAllUsesWith(NewAllocaPtr);
IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, ASan.LongSize/8)),
IntptrPtrTy);
GlobalVariable *StackDescriptionGlobal =
- createPrivateGlobalForString(*F.getParent(), L.DescriptionString);
+ createPrivateGlobalForString(*F.getParent(), L.DescriptionString,
+ /*AllowMerging*/true);
Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal,
IntptrTy);
IRB.CreateStore(Description, BasePlus1);
Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true);
- // Unpoison the stack before all ret instructions.
- for (size_t i = 0, n = RetVec.size(); i < n; i++) {
- Instruction *Ret = RetVec[i];
+ // (Un)poison the stack before all ret instructions.
+ for (auto Ret : RetVec) {
IRBuilder<> IRBRet(Ret);
// Mark the current frame as retired.
IRBRet.CreateStore(ConstantInt::get(IntptrTy, kRetiredStackFrameMagic),
BasePlus0);
- // Unpoison the stack.
- poisonRedZones(L.ShadowBytes, IRBRet, ShadowBase, false);
if (DoStackMalloc) {
assert(StackMallocIdx >= 0);
- // In use-after-return mode, mark the whole stack frame unaddressable.
+ // 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(FakeStack) = 0
+ // else
+ // __asan_stack_free_N(FakeStack, LocalStackSize)
+ // else
+ // <This is not a fake stack; unpoison the redzones>
+ Value *Cmp =
+ IRBRet.CreateICmpNE(FakeStack, Constant::getNullValue(IntptrTy));
+ TerminatorInst *ThenTerm, *ElseTerm;
+ SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
+
+ IRBuilder<> IRBPoison(ThenTerm);
if (StackMallocIdx <= 4) {
- // For small sizes inline the whole thing:
- // if LocalStackBase != OrigStackBase:
- // memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize);
- // **SavedFlagPtr(LocalStackBase) = 0
- // FIXME: if LocalStackBase != OrigStackBase don't call poisonRedZones.
- Value *Cmp = IRBRet.CreateICmpNE(LocalStackBase, OrigStackBase);
- TerminatorInst *PoisonTerm =
- SplitBlockAndInsertIfThen(cast<Instruction>(Cmp), false);
- IRBuilder<> IRBPoison(PoisonTerm);
int ClassSize = kMinStackMallocSize << StackMallocIdx;
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_*.
- IRBRet.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase,
- ConstantInt::get(IntptrTy, LocalStackSize),
- OrigStackBase);
+ IRBPoison.CreateCall2(AsanStackFreeFunc[StackMallocIdx], FakeStack,
+ ConstantInt::get(IntptrTy, LocalStackSize));
}
+
+ IRBuilder<> IRBElse(ElseTerm);
+ poisonRedZones(L.ShadowBytes, IRBElse, ShadowBase, false);
} 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);
}
}
+ if (ClInstrumentAllocas)
+ // Unpoison dynamic allocas.
+ for (auto &AllocaCall : DynamicAllocaVec)
+ unpoisonDynamicAlloca(AllocaCall);
+
// We are done. Remove the old unused alloca instructions.
- for (size_t i = 0, n = AllocaVec.size(); i < n; i++)
- AllocaVec[i]->eraseFromParent();
+ for (auto AI : AllocaVec)
+ AI->eraseFromParent();
}
void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
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 : 0;
+ return 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);
return I->second;
// Store 0 while we're calculating alloca for value V to avoid
// infinite recursion if the value references itself.
- AllocaForValue[V] = 0;
- AllocaInst *Res = 0;
+ AllocaForValue[V] = nullptr;
+ AllocaInst *Res = nullptr;
if (CastInst *CI = dyn_cast<CastInst>(V))
Res = findAllocaForValue(CI->getOperand(0));
else if (PHINode *PN = dyn_cast<PHINode>(V)) {
if (IncValue == PN) continue;
AllocaInst *IncValueAI = findAllocaForValue(IncValue);
// AI for incoming values should exist and should all be equal.
- if (IncValueAI == 0 || (Res != 0 && IncValueAI != Res))
- return 0;
+ if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
+ return nullptr;
Res = IncValueAI;
}
}
- if (Res != 0)
+ 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 (!ASan.DL->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 (ASan.DL->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 = ASan.DL->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++;
+}