#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
+#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/ASanStackFrameLayout.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
static const char *const kAsanModuleCtorName = "asan.module_ctor";
static const char *const kAsanModuleDtorName = "asan.module_dtor";
-static const int kAsanCtorAndDtorPriority = 1;
+static const uint64_t kAsanCtorAndDtorPriority = 1;
static const char *const kAsanReportErrorTemplate = "__asan_report_";
static const char *const kAsanReportLoadN = "__asan_report_load_n";
static const char *const kAsanReportStoreN = "__asan_report_store_n";
static const char *const kAsanInitName = "__asan_init_v4";
static const char *const kAsanCovModuleInitName = "__sanitizer_cov_module_init";
static const char *const kAsanCovName = "__sanitizer_cov";
+static const char *const kAsanCovIndirCallName = "__sanitizer_cov_indir_call16";
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 cl::opt<bool> ClGlobals("asan-globals",
cl::desc("Handle global objects"), cl::Hidden, cl::init(true));
static cl::opt<int> ClCoverage("asan-coverage",
- cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks"),
+ cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks, "
+ "3: all blocks and critical edges, "
+ "4: above plus indirect calls"),
cl::Hidden, cl::init(false));
static cl::opt<int> ClCoverageBlockThreshold("asan-coverage-block-threshold",
cl::desc("Add coverage instrumentation only to the entry block if there "
"Number of optimized accesses to global vars");
namespace {
+/// 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 = cast<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
+ ColumnNo = cast<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
+ }
+};
+
/// Frontend-provided metadata for global variables.
class GlobalsMetadata {
public:
struct Entry {
Entry()
- : SourceLoc(nullptr), Name(nullptr), IsDynInit(false),
+ : SourceLoc(), Name(), IsDynInit(false),
IsBlacklisted(false) {}
- GlobalVariable *SourceLoc;
- GlobalVariable *Name;
+ LocationMetadata SourceLoc;
+ StringRef Name;
bool IsDynInit;
bool IsBlacklisted;
};
// We can already have an entry for GV if it was merged with another
// global.
Entry &E = Entries[GV];
- if (Value *Loc = MDN->getOperand(1)) {
- GlobalVariable *GVLoc = cast<GlobalVariable>(Loc);
- E.SourceLoc = GVLoc;
- addSourceLocationGlobal(GVLoc);
- }
+ if (Value *Loc = MDN->getOperand(1))
+ E.SourceLoc.parse(cast<MDNode>(Loc));
if (Value *Name = MDN->getOperand(2)) {
- GlobalVariable *GVName = cast<GlobalVariable>(Name);
- E.Name = GVName;
- InstrumentationGlobals.insert(GVName);
+ MDString *MDName = cast<MDString>(Name);
+ E.Name = MDName->getString();
}
ConstantInt *IsDynInit = cast<ConstantInt>(MDN->getOperand(3));
E.IsDynInit |= IsDynInit->isOne();
return (Pos != Entries.end()) ? Pos->second : Entry();
}
- /// Check if the global was generated by the instrumentation
- /// (we don't want to instrument it again in this case).
- bool isInstrumentationGlobal(GlobalVariable *G) const {
- return InstrumentationGlobals.count(G);
- }
-
private:
bool inited_;
DenseMap<GlobalVariable*, Entry> Entries;
- // Globals generated by the frontend instrumentation.
- DenseSet<GlobalVariable*> InstrumentationGlobals;
-
- void addSourceLocationGlobal(GlobalVariable *SourceLocGV) {
- // Source location global is a struct with layout:
- // {
- // filename,
- // i32 line_number,
- // i32 column_number,
- // }
- InstrumentationGlobals.insert(SourceLocGV);
- ConstantStruct *Contents =
- cast<ConstantStruct>(SourceLocGV->getInitializer());
- GlobalVariable *FilenameGV = cast<GlobalVariable>(Contents->getOperand(0));
- InstrumentationGlobals.insert(FilenameGV);
- }
};
/// This struct defines the shadow mapping using the rule:
static ShadowMapping getShadowMapping(const Module &M, int LongSize) {
llvm::Triple TargetTriple(M.getTargetTriple());
bool IsAndroid = TargetTriple.getEnvironment() == llvm::Triple::Android;
- bool IsIOS = TargetTriple.getOS() == llvm::Triple::IOS;
+ bool IsIOS = TargetTriple.isiOS();
bool IsFreeBSD = TargetTriple.getOS() == llvm::Triple::FreeBSD;
bool IsLinux = TargetTriple.getOS() == llvm::Triple::Linux;
bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
/// AddressSanitizer: instrument the code in module to find memory bugs.
struct AddressSanitizer : public FunctionPass {
- AddressSanitizer() : FunctionPass(ID) {}
+ AddressSanitizer() : FunctionPass(ID) {
+ initializeBreakCriticalEdgesPass(*PassRegistry::getPassRegistry());
+ }
const char *getPassName() const override {
return "AddressSanitizerFunctionPass";
}
bool doInitialization(Module &M) override;
static char ID; // Pass identification, replacement for typeid
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ if (ClCoverage >= 3)
+ AU.addRequiredID(BreakCriticalEdgesID);
+ }
+
private:
void initializeCallbacks(Module &M);
bool LooksLikeCodeInBug11395(Instruction *I);
bool GlobalIsLinkerInitialized(GlobalVariable *G);
- bool InjectCoverage(Function &F, const ArrayRef<BasicBlock*> AllBlocks);
+ void InjectCoverageForIndirectCalls(Function &F,
+ ArrayRef<Instruction *> IndirCalls);
+ bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
+ ArrayRef<Instruction *> IndirCalls);
void InjectCoverageAtBlock(Function &F, BasicBlock &BB);
LLVMContext *C;
Function *AsanInitFunction;
Function *AsanHandleNoReturnFunc;
Function *AsanCovFunction;
+ Function *AsanCovIndirCallFunction;
Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
// This array is indexed by AccessIsWrite and log2(AccessSize).
Function *AsanErrorCallback[2][kNumberOfAccessSizes];
}
/// 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);
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;
}
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(Cmp, InsertBefore, false);
+ SplitBlockAndInsertIfThen(Cmp, InsertBefore, false,
+ MDBuilder(*C).createBranchWeights(1, 100000));
assert(dyn_cast<BranchInst>(CheckTerm)->isUnconditional());
BasicBlock *NextBB = CheckTerm->getSuccessor(0);
IRB.SetInsertPoint(CheckTerm);
ConstantStruct *CS = cast<ConstantStruct>(OP);
// Must have a function or null ptr.
- // (CS->getOperand(0) is the init priority.)
if (Function* F = dyn_cast<Function>(CS->getOperand(1))) {
- if (F->getName() != kAsanModuleCtorName)
- poisonOneInitializer(*F, ModuleName);
+ 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);
}
}
}
DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
if (GlobalsMD.get(G).IsBlacklisted) return false;
- if (GlobalsMD.isInstrumentationGlobal(G)) return false;
if (!Ty->isSized()) return false;
if (!G->hasInitializer()) return false;
if (GlobalWasGeneratedByAsan(G)) return false; // Our own global.
GlobalVariable *G = GlobalsToChange[i];
auto MD = GlobalsMD.get(G);
- // Create string holding the global name unless it was provided by
- // the metadata.
- GlobalVariable *Name =
- MD.Name ? MD.Name : createPrivateGlobalForString(M, G->getName(),
- /*AllowMerging*/ true);
+ // 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();
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),
ConstantInt::get(IntptrTy, SizeInBytes),
ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
ConstantExpr::getPointerCast(Name, IntptrTy),
ConstantExpr::getPointerCast(ModuleName, IntptrTy),
- ConstantInt::get(IntptrTy, MD.IsDynInit),
- MD.SourceLoc ? ConstantExpr::getPointerCast(MD.SourceLoc, IntptrTy)
- : ConstantInt::get(IntptrTy, 0),
- NULL);
+ ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc, NULL);
if (ClInitializers && MD.IsDynInit)
HasDynamicallyInitializedGlobals = true;
M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction(
kAsanCovName, IRB.getVoidTy(), NULL));
+ AsanCovIndirCallFunction = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanCovIndirCallName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
+
AsanPtrCmpFunction = checkInterfaceFunction(M.getOrInsertFunction(
kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanPtrSubFunction = checkInterfaceFunction(M.getOrInsertFunction(
break;
}
- DebugLoc EntryLoc = IP->getDebugLoc().getFnDebugLoc(*C);
+ DebugLoc EntryLoc = &BB == &F.getEntryBlock()
+ ? IP->getDebugLoc().getFnDebugLoc(*C)
+ : IP->getDebugLoc();
IRBuilder<> IRB(IP);
IRB.SetCurrentDebugLocation(EntryLoc);
Type *Int8Ty = IRB.getInt8Ty();
Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
IRB.SetInsertPoint(Ins);
IRB.SetCurrentDebugLocation(EntryLoc);
- // 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.
+ // __sanitizer_cov gets the PC of the instruction using GET_CALLER_PC.
IRB.CreateCall(AsanCovFunction);
StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
Store->setAtomic(Monotonic);
// as the function and inject this code into the entry block (-asan-coverage=1)
// or all blocks (-asan-coverage=2):
// if (*Guard) {
-// __sanitizer_cov(&F);
+// __sanitizer_cov();
// *Guard = 1;
// }
// The accesses to Guard are atomic. The rest of the logic is
// a) get the functionality to users earlier and
// b) collect usage statistics to help improve Clang coverage design.
bool AddressSanitizer::InjectCoverage(Function &F,
- const ArrayRef<BasicBlock *> AllBlocks) {
+ ArrayRef<BasicBlock *> AllBlocks,
+ ArrayRef<Instruction*> IndirCalls) {
if (!ClCoverage) return false;
if (ClCoverage == 1 ||
for (auto BB : AllBlocks)
InjectCoverageAtBlock(F, *BB);
}
+ InjectCoverageForIndirectCalls(F, IndirCalls);
return true;
}
+// On every indirect call we call a run-time function
+// __sanitizer_cov_indir_call* with two parameters:
+// - callee address,
+// - global cache array that contains kCacheSize pointers (zero-initialed).
+// The cache is used to speed up recording the caller-callee pairs.
+// The address of the caller is passed implicitly via caller PC.
+// kCacheSize is encoded in the name of the run-time function.
+void AddressSanitizer::InjectCoverageForIndirectCalls(
+ Function &F, ArrayRef<Instruction *> IndirCalls) {
+ if (ClCoverage < 4 || IndirCalls.empty()) return;
+ const int kCacheSize = 16;
+ const int kCacheAlignment = 64; // Align for better performance.
+ Type *Ty = ArrayType::get(IntptrTy, kCacheSize);
+ GlobalVariable *CalleeCache =
+ new GlobalVariable(*F.getParent(), Ty, false, GlobalValue::PrivateLinkage,
+ Constant::getNullValue(Ty), "__asan_gen_callee_cache");
+ CalleeCache->setAlignment(kCacheAlignment);
+ for (auto I : IndirCalls) {
+ IRBuilder<> IRB(I);
+ CallSite CS(I);
+ IRB.CreateCall2(AsanCovIndirCallFunction,
+ IRB.CreatePointerCast(CS.getCalledValue(), IntptrTy),
+ IRB.CreatePointerCast(CalleeCache, IntptrTy));
+ }
+}
+
bool AddressSanitizer::runOnFunction(Function &F) {
if (&F == AsanCtorFunction) return false;
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
SmallVector<Instruction*, 8> NoReturnCalls;
SmallVector<BasicBlock*, 16> AllBlocks;
SmallVector<Instruction*, 16> PointerComparisonsOrSubtracts;
+ SmallVector<Instruction*, 8> IndirCalls;
int NumAllocas = 0;
bool IsWrite;
unsigned Alignment;
TempsToInstrument.clear();
if (CS.doesNotReturn())
NoReturnCalls.push_back(CS.getInstruction());
+ if (ClCoverage >= 4 && !CS.getCalledFunction())
+ IndirCalls.push_back(&Inst);
}
continue;
}
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
- if (InjectCoverage(F, AllBlocks))
+ if (InjectCoverage(F, AllBlocks, IndirCalls))
res = true;
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
}
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();
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