#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
"__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_v5";
+static const char *const kAsanInitName = "__asan_init";
+static const char *const kAsanVersionCheckName =
+ "__asan_version_mismatch_check_v6";
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";
cl::init("__asan_"));
static cl::opt<bool> ClInstrumentAllocas("asan-instrument-allocas",
cl::desc("instrument dynamic allocas"),
- cl::Hidden, cl::init(false));
+ cl::Hidden, cl::init(true));
static cl::opt<bool> ClSkipPromotableAllocas(
"asan-skip-promotable-allocas",
cl::desc("Do not instrument promotable allocas"), cl::Hidden,
static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
bool IsKasan) {
- bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
+ bool IsAndroid = TargetTriple.isAndroid();
bool IsIOS = TargetTriple.isiOS();
bool IsFreeBSD = TargetTriple.isOSFreeBSD();
bool IsLinux = TargetTriple.isOSLinux();
ShadowMapping Mapping;
if (LongSize == 32) {
+ // Android is always PIE, which means that the beginning of the address
+ // space is always available.
if (IsAndroid)
Mapping.Offset = 0;
else if (IsMIPS32)
// 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));
+ Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64
+ && !(Mapping.Offset & (Mapping.Offset - 1));
return Mapping;
}
Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
bool runOnFunction(Function &F) override;
bool maybeInsertAsanInitAtFunctionEntry(Function &F);
+ void markEscapedLocalAllocas(Function &F);
bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid
bool isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis, Value *Addr,
uint64_t TypeSize) const;
+ /// Helper to cleanup per-function state.
+ struct FunctionStateRAII {
+ AddressSanitizer *Pass;
+ FunctionStateRAII(AddressSanitizer *Pass) : Pass(Pass) {
+ assert(Pass->ProcessedAllocas.empty() &&
+ "last pass forgot to clear cache");
+ }
+ ~FunctionStateRAII() { Pass->ProcessedAllocas.clear(); }
+ };
+
LLVMContext *C;
Triple TargetTriple;
int LongSize;
ShadowMapping Mapping;
SmallVector<AllocaInst *, 16> AllocaVec;
+ SmallSetVector<AllocaInst *, 16> NonInstrumentedStaticAllocaVec;
SmallVector<Instruction *, 8> RetVec;
unsigned StackAlignment;
SmallVector<AllocaInst *, 1> DynamicAllocaVec;
SmallVector<IntrinsicInst *, 1> StackRestoreVec;
AllocaInst *DynamicAllocaLayout = nullptr;
+ IntrinsicInst *LocalEscapeCall = nullptr;
// Maps Value to an AllocaInst from which the Value is originated.
typedef DenseMap<Value *, AllocaInst *> AllocaForValueMapTy;
AllocaForValueMapTy AllocaForValue;
- bool HasNonEmptyInlineAsm;
+ bool HasNonEmptyInlineAsm = false;
+ bool HasReturnsTwiceCall = false;
std::unique_ptr<CallInst> EmptyInlineAsm;
FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
IntptrPtrTy(PointerType::get(IntptrTy, 0)),
Mapping(ASan.Mapping),
StackAlignment(1 << Mapping.Scale),
- HasNonEmptyInlineAsm(false),
EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
bool runOnFunction() {
/// \brief Collect Alloca instructions we want (and can) handle.
void visitAllocaInst(AllocaInst &AI) {
- if (!ASan.isInterestingAlloca(AI)) return;
+ if (!ASan.isInterestingAlloca(AI)) {
+ if (AI.isStaticAlloca()) NonInstrumentedStaticAllocaVec.insert(&AI);
+ return;
+ }
StackAlignment = std::max(StackAlignment, AI.getAlignment());
if (ASan.isDynamicAlloca(AI))
void visitIntrinsicInst(IntrinsicInst &II) {
Intrinsic::ID ID = II.getIntrinsicID();
if (ID == Intrinsic::stackrestore) StackRestoreVec.push_back(&II);
+ if (ID == Intrinsic::localescape) LocalEscapeCall = &II;
if (!ClCheckLifetime) return;
if (ID != Intrinsic::lifetime_start && ID != Intrinsic::lifetime_end)
return;
AllocaPoisonCallVec.push_back(APC);
}
- void visitCallInst(CallInst &CI) {
- HasNonEmptyInlineAsm |=
- CI.isInlineAsm() && !CI.isIdenticalTo(EmptyInlineAsm.get());
+ void visitCallSite(CallSite CS) {
+ Instruction *I = CS.getInstruction();
+ if (CallInst *CI = dyn_cast<CallInst>(I)) {
+ HasNonEmptyInlineAsm |=
+ CI->isInlineAsm() && !CI->isIdenticalTo(EmptyInlineAsm.get());
+ HasReturnsTwiceCall |= CI->canReturnTwice();
+ }
}
// ---------------------- Helpers.
Instruction *ThenTerm, Value *ValueIfFalse);
};
-} // namespace
+} // anonymous namespace
char AddressSanitizer::ID = 0;
INITIALIZE_PASS_BEGIN(
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
false)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(
AddressSanitizer, "asan",
"AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
getAllocaSizeInBytes(&AI) > 0 &&
// We are only interested in allocas not promotable to registers.
// Promotable allocas are common under -O0.
- (!ClSkipPromotableAllocas || !isAllocaPromotable(&AI) ||
- isDynamicAlloca(AI)));
+ (!ClSkipPromotableAllocas || !isAllocaPromotable(&AI)) &&
+ // inalloca allocas are not treated as static, and we don't want
+ // dynamic alloca instrumentation for them as well.
+ !AI.isUsedWithInAlloca());
ProcessedAllocas[&AI] = IsInteresting;
return IsInteresting;
} else {
return false;
}
- if (!isPointerOperand(I->getOperand(0)) ||
- !isPointerOperand(I->getOperand(1)))
- return false;
- return true;
+ return isPointerOperand(I->getOperand(0)) &&
+ isPointerOperand(I->getOperand(1));
}
bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
// 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)) &&
+ if (G && (!ClInitializers || GlobalIsLinkerInitialized(G)) &&
isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
NumOptimizedAccessesToGlobalVar++;
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.front(),
+ GlobalInit.front().getFirstInsertionPt());
// Add a call to poison all external globals before the given function starts.
Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
// Globals from llvm.metadata aren't emitted, do not instrument them.
if (Section == "llvm.metadata") return false;
+ // Do not instrument globals from special LLVM sections.
+ if (Section.find("__llvm") != StringRef::npos) return false;
+
+ // Do not instrument function pointers to initialization and termination
+ // routines: dynamic linker will not properly handle redzones.
+ if (Section.startswith(".preinit_array") ||
+ Section.startswith(".init_array") ||
+ Section.startswith(".fini_array")) {
+ return false;
+ }
// Callbacks put into the CRT initializer/terminator sections
// should not be instrumented.
const std::string ExpStr = Exp ? "exp_" : "";
const std::string SuffixStr = CompileKernel ? "N" : "_n";
const std::string EndingStr = CompileKernel ? "_noabort" : "";
- const Type *ExpType = Exp ? Type::getInt32Ty(*C) : nullptr;
+ Type *ExpType = Exp ? Type::getInt32Ty(*C) : nullptr;
// TODO(glider): for KASan builds add _noabort to error reporting
// functions and make them actually noabort (remove the UnreachableInst).
AsanErrorCallbackSized[AccessIsWrite][Exp] =
if (!CompileKernel) {
std::tie(AsanCtorFunction, AsanInitFunction) =
- createSanitizerCtorAndInitFunctions(M, kAsanModuleCtorName, kAsanInitName,
- /*InitArgTypes=*/{},
- /*InitArgs=*/{});
+ createSanitizerCtorAndInitFunctions(
+ M, kAsanModuleCtorName, kAsanInitName,
+ /*InitArgTypes=*/{}, /*InitArgs=*/{}, kAsanVersionCheckName);
appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
}
Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
// We cannot just ignore these methods, because they may call other
// instrumented functions.
if (F.getName().find(" load]") != std::string::npos) {
- IRBuilder<> IRB(F.begin()->begin());
+ IRBuilder<> IRB(&F.front(), F.front().begin());
IRB.CreateCall(AsanInitFunction, {});
return true;
}
return false;
}
+void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
+ // Find the one possible call to llvm.localescape and pre-mark allocas passed
+ // to it as uninteresting. This assumes we haven't started processing allocas
+ // yet. This check is done up front because iterating the use list in
+ // isInterestingAlloca would be algorithmically slower.
+ assert(ProcessedAllocas.empty() && "must process localescape before allocas");
+
+ // Try to get the declaration of llvm.localescape. If it's not in the module,
+ // we can exit early.
+ if (!F.getParent()->getFunction("llvm.localescape")) return;
+
+ // Look for a call to llvm.localescape call in the entry block. It can't be in
+ // any other block.
+ for (Instruction &I : F.getEntryBlock()) {
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
+ if (II && II->getIntrinsicID() == Intrinsic::localescape) {
+ // We found a call. Mark all the allocas passed in as uninteresting.
+ for (Value *Arg : II->arg_operands()) {
+ AllocaInst *AI = dyn_cast<AllocaInst>(Arg->stripPointerCasts());
+ assert(AI && AI->isStaticAlloca() &&
+ "non-static alloca arg to localescape");
+ ProcessedAllocas[AI] = false;
+ }
+ break;
+ }
+ }
+}
+
bool AddressSanitizer::runOnFunction(Function &F) {
if (&F == AsanCtorFunction) return false;
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName()) return false;
+ FunctionStateRAII CleanupObj(this);
+
+ // We can't instrument allocas used with llvm.localescape. Only static allocas
+ // can be passed to that intrinsic.
+ markEscapedLocalAllocas(F);
+
// We want to instrument every address only once per basic block (unless there
// are calls between uses).
SmallSet<Value *, 16> TempsToInstrument;
}
}
-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,
void FunctionStackPoisoner::poisonStack() {
assert(AllocaVec.size() > 0 || DynamicAllocaVec.size() > 0);
+ // Insert poison calls for lifetime intrinsics for alloca.
+ bool HavePoisonedAllocas = false;
+ for (const auto &APC : AllocaPoisonCallVec) {
+ assert(APC.InsBefore);
+ assert(APC.AI);
+ IRBuilder<> IRB(APC.InsBefore);
+ poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
+ HavePoisonedAllocas |= APC.DoPoison;
+ }
+
if (ClInstrumentAllocas && DynamicAllocaVec.size() > 0) {
// Handle dynamic allocas.
createDynamicAllocasInitStorage();
unpoisonDynamicAllocas();
}
- if (AllocaVec.size() == 0) return;
+ if (AllocaVec.empty()) return;
int StackMallocIdx = -1;
- DebugLoc EntryDebugLocation = getFunctionEntryDebugLocation(F);
+ DebugLoc EntryDebugLocation;
+ if (auto SP = getDISubprogram(&F))
+ EntryDebugLocation = DebugLoc::get(SP->getScopeLine(), 0, SP);
Instruction *InsBefore = AllocaVec[0];
IRBuilder<> IRB(InsBefore);
IRB.SetCurrentDebugLocation(EntryDebugLocation);
+ // Make sure non-instrumented allocas stay in the entry block. Otherwise,
+ // debug info is broken, because only entry-block allocas are treated as
+ // regular stack slots.
+ auto InsBeforeB = InsBefore->getParent();
+ assert(InsBeforeB == &F.getEntryBlock());
+ for (BasicBlock::iterator I(InsBefore); I != InsBeforeB->end(); ++I)
+ if (auto *AI = dyn_cast<AllocaInst>(I))
+ if (NonInstrumentedStaticAllocaVec.count(AI) > 0)
+ AI->moveBefore(InsBefore);
+
+ // If we have a call to llvm.localescape, keep it in the entry block.
+ if (LocalEscapeCall) LocalEscapeCall->moveBefore(InsBefore);
+
SmallVector<ASanStackVariableDescription, 16> SVD;
SVD.reserve(AllocaVec.size());
for (AllocaInst *AI : AllocaVec) {
uint64_t LocalStackSize = L.FrameSize;
bool DoStackMalloc = ClUseAfterReturn && !ASan.CompileKernel &&
LocalStackSize <= kMaxStackMallocSize;
- // Don't do dynamic alloca in presence of inline asm: too often it makes
- // assumptions on which registers are available. Don't do stack malloc in the
- // presence of inline asm on 32-bit platforms for the same reason.
- bool DoDynamicAlloca = ClDynamicAllocaStack && !HasNonEmptyInlineAsm;
- DoStackMalloc &= !HasNonEmptyInlineAsm || ASan.LongSize != 32;
+ bool DoDynamicAlloca = ClDynamicAllocaStack;
+ // Don't do dynamic alloca or stack malloc if:
+ // 1) There is inline asm: too often it makes assumptions on which registers
+ // are available.
+ // 2) There is a returns_twice call (typically setjmp), which is
+ // optimization-hostile, and doesn't play well with introduced indirect
+ // register-relative calculation of local variable addresses.
+ DoDynamicAlloca &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
+ DoStackMalloc &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
Value *StaticAlloca =
DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);
DoDynamicAlloca ? createAllocaForLayout(IRB, L, true) : StaticAlloca;
}
- // Insert poison calls for lifetime intrinsics for alloca.
- bool HavePoisonedAllocas = false;
- for (const auto &APC : AllocaPoisonCallVec) {
- assert(APC.InsBefore);
- assert(APC.AI);
- IRBuilder<> IRB(APC.InsBefore);
- poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
- HavePoisonedAllocas |= APC.DoPoison;
- }
-
// Replace Alloca instructions with base+offset.
for (const auto &Desc : SVD) {
AllocaInst *AI = Desc.AI;
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