1 //===-- DataFlowSanitizer.cpp - dynamic data flow analysis ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 /// This file is a part of DataFlowSanitizer, a generalised dynamic data flow
13 /// Unlike other Sanitizer tools, this tool is not designed to detect a specific
14 /// class of bugs on its own. Instead, it provides a generic dynamic data flow
15 /// analysis framework to be used by clients to help detect application-specific
16 /// issues within their own code.
18 /// The analysis is based on automatic propagation of data flow labels (also
19 /// known as taint labels) through a program as it performs computation. Each
20 /// byte of application memory is backed by two bytes of shadow memory which
21 /// hold the label. On Linux/x86_64, memory is laid out as follows:
23 /// +--------------------+ 0x800000000000 (top of memory)
24 /// | application memory |
25 /// +--------------------+ 0x700000008000 (kAppAddr)
29 /// +--------------------+ 0x200200000000 (kUnusedAddr)
31 /// +--------------------+ 0x200000000000 (kUnionTableAddr)
33 /// +--------------------+ 0x000000010000 (kShadowAddr)
34 /// | reserved by kernel |
35 /// +--------------------+ 0x000000000000
37 /// To derive a shadow memory address from an application memory address,
38 /// bits 44-46 are cleared to bring the address into the range
39 /// [0x000000008000,0x100000000000). Then the address is shifted left by 1 to
40 /// account for the double byte representation of shadow labels and move the
41 /// address into the shadow memory range. See the function
42 /// DataFlowSanitizer::getShadowAddress below.
44 /// For more information, please refer to the design document:
45 /// http://clang.llvm.org/docs/DataFlowSanitizerDesign.html
47 #include "llvm/Transforms/Instrumentation.h"
48 #include "llvm/ADT/DenseMap.h"
49 #include "llvm/ADT/DenseSet.h"
50 #include "llvm/ADT/DepthFirstIterator.h"
51 #include "llvm/ADT/StringExtras.h"
52 #include "llvm/Analysis/ValueTracking.h"
53 #include "llvm/IR/IRBuilder.h"
54 #include "llvm/IR/InlineAsm.h"
55 #include "llvm/IR/LLVMContext.h"
56 #include "llvm/IR/MDBuilder.h"
57 #include "llvm/IR/Type.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/InstVisitor.h"
60 #include "llvm/Pass.h"
61 #include "llvm/Support/CommandLine.h"
62 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
63 #include "llvm/Transforms/Utils/Local.h"
64 #include "llvm/Transforms/Utils/SpecialCaseList.h"
69 // The -dfsan-preserve-alignment flag controls whether this pass assumes that
70 // alignment requirements provided by the input IR are correct. For example,
71 // if the input IR contains a load with alignment 8, this flag will cause
72 // the shadow load to have alignment 16. This flag is disabled by default as
73 // we have unfortunately encountered too much code (including Clang itself;
74 // see PR14291) which performs misaligned access.
75 static cl::opt<bool> ClPreserveAlignment(
76 "dfsan-preserve-alignment",
77 cl::desc("respect alignment requirements provided by input IR"), cl::Hidden,
80 // The ABI list file controls how shadow parameters are passed. The pass treats
81 // every function labelled "uninstrumented" in the ABI list file as conforming
82 // to the "native" (i.e. unsanitized) ABI. Unless the ABI list contains
83 // additional annotations for those functions, a call to one of those functions
84 // will produce a warning message, as the labelling behaviour of the function is
85 // unknown. The other supported annotations are "functional" and "discard",
86 // which are described below under DataFlowSanitizer::WrapperKind.
87 static cl::opt<std::string> ClABIListFile(
89 cl::desc("File listing native ABI functions and how the pass treats them"),
92 // Controls whether the pass uses IA_Args or IA_TLS as the ABI for instrumented
93 // functions (see DataFlowSanitizer::InstrumentedABI below).
94 static cl::opt<bool> ClArgsABI(
96 cl::desc("Use the argument ABI rather than the TLS ABI"),
99 // Controls whether the pass includes or ignores the labels of pointers in load
101 static cl::opt<bool> ClCombinePointerLabelsOnLoad(
102 "dfsan-combine-pointer-labels-on-load",
103 cl::desc("Combine the label of the pointer with the label of the data when "
104 "loading from memory."),
105 cl::Hidden, cl::init(true));
107 // Controls whether the pass includes or ignores the labels of pointers in
108 // stores instructions.
109 static cl::opt<bool> ClCombinePointerLabelsOnStore(
110 "dfsan-combine-pointer-labels-on-store",
111 cl::desc("Combine the label of the pointer with the label of the data when "
112 "storing in memory."),
113 cl::Hidden, cl::init(false));
115 static cl::opt<bool> ClDebugNonzeroLabels(
116 "dfsan-debug-nonzero-labels",
117 cl::desc("Insert calls to __dfsan_nonzero_label on observing a parameter, "
118 "load or return with a nonzero label"),
123 class DataFlowSanitizer : public ModulePass {
124 friend struct DFSanFunction;
125 friend class DFSanVisitor;
131 /// Which ABI should be used for instrumented functions?
132 enum InstrumentedABI {
133 /// Argument and return value labels are passed through additional
134 /// arguments and by modifying the return type.
137 /// Argument and return value labels are passed through TLS variables
138 /// __dfsan_arg_tls and __dfsan_retval_tls.
142 /// How should calls to uninstrumented functions be handled?
144 /// This function is present in an uninstrumented form but we don't know
145 /// how it should be handled. Print a warning and call the function anyway.
146 /// Don't label the return value.
149 /// This function does not write to (user-accessible) memory, and its return
150 /// value is unlabelled.
153 /// This function does not write to (user-accessible) memory, and the label
154 /// of its return value is the union of the label of its arguments.
157 /// Instead of calling the function, a custom wrapper __dfsw_F is called,
158 /// where F is the name of the function. This function may wrap the
159 /// original function or provide its own implementation. This is similar to
160 /// the IA_Args ABI, except that IA_Args uses a struct return type to
161 /// pass the return value shadow in a register, while WK_Custom uses an
162 /// extra pointer argument to return the shadow. This allows the wrapped
163 /// form of the function type to be expressed in C.
167 const DataLayout *DL;
170 IntegerType *ShadowTy;
171 PointerType *ShadowPtrTy;
172 IntegerType *IntptrTy;
173 ConstantInt *ZeroShadow;
174 ConstantInt *ShadowPtrMask;
175 ConstantInt *ShadowPtrMul;
178 void *(*GetArgTLSPtr)();
179 void *(*GetRetvalTLSPtr)();
181 Constant *GetRetvalTLS;
182 FunctionType *DFSanUnionFnTy;
183 FunctionType *DFSanUnionLoadFnTy;
184 FunctionType *DFSanUnimplementedFnTy;
185 FunctionType *DFSanSetLabelFnTy;
186 FunctionType *DFSanNonzeroLabelFnTy;
187 Constant *DFSanUnionFn;
188 Constant *DFSanUnionLoadFn;
189 Constant *DFSanUnimplementedFn;
190 Constant *DFSanSetLabelFn;
191 Constant *DFSanNonzeroLabelFn;
192 MDNode *ColdCallWeights;
193 OwningPtr<SpecialCaseList> ABIList;
194 DenseMap<Value *, Function *> UnwrappedFnMap;
195 AttributeSet ReadOnlyNoneAttrs;
197 Value *getShadowAddress(Value *Addr, Instruction *Pos);
198 Value *combineShadows(Value *V1, Value *V2, Instruction *Pos);
199 bool isInstrumented(const Function *F);
200 bool isInstrumented(const GlobalAlias *GA);
201 FunctionType *getArgsFunctionType(FunctionType *T);
202 FunctionType *getTrampolineFunctionType(FunctionType *T);
203 FunctionType *getCustomFunctionType(FunctionType *T);
204 InstrumentedABI getInstrumentedABI();
205 WrapperKind getWrapperKind(Function *F);
206 void addGlobalNamePrefix(GlobalValue *GV);
207 Function *buildWrapperFunction(Function *F, StringRef NewFName,
208 GlobalValue::LinkageTypes NewFLink,
209 FunctionType *NewFT);
210 Constant *getOrBuildTrampolineFunction(FunctionType *FT, StringRef FName);
213 DataFlowSanitizer(StringRef ABIListFile = StringRef(),
214 void *(*getArgTLS)() = 0, void *(*getRetValTLS)() = 0);
216 bool doInitialization(Module &M) override;
217 bool runOnModule(Module &M) override;
220 struct DFSanFunction {
221 DataFlowSanitizer &DFS;
223 DataFlowSanitizer::InstrumentedABI IA;
227 AllocaInst *LabelReturnAlloca;
228 DenseMap<Value *, Value *> ValShadowMap;
229 DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
230 std::vector<std::pair<PHINode *, PHINode *> > PHIFixups;
231 DenseSet<Instruction *> SkipInsts;
232 DenseSet<Value *> NonZeroChecks;
234 DFSanFunction(DataFlowSanitizer &DFS, Function *F, bool IsNativeABI)
235 : DFS(DFS), F(F), IA(DFS.getInstrumentedABI()),
236 IsNativeABI(IsNativeABI), ArgTLSPtr(0), RetvalTLSPtr(0),
237 LabelReturnAlloca(0) {}
238 Value *getArgTLSPtr();
239 Value *getArgTLS(unsigned Index, Instruction *Pos);
240 Value *getRetvalTLS();
241 Value *getShadow(Value *V);
242 void setShadow(Instruction *I, Value *Shadow);
243 Value *combineOperandShadows(Instruction *Inst);
244 Value *loadShadow(Value *ShadowAddr, uint64_t Size, uint64_t Align,
246 void storeShadow(Value *Addr, uint64_t Size, uint64_t Align, Value *Shadow,
250 class DFSanVisitor : public InstVisitor<DFSanVisitor> {
253 DFSanVisitor(DFSanFunction &DFSF) : DFSF(DFSF) {}
255 void visitOperandShadowInst(Instruction &I);
257 void visitBinaryOperator(BinaryOperator &BO);
258 void visitCastInst(CastInst &CI);
259 void visitCmpInst(CmpInst &CI);
260 void visitGetElementPtrInst(GetElementPtrInst &GEPI);
261 void visitLoadInst(LoadInst &LI);
262 void visitStoreInst(StoreInst &SI);
263 void visitReturnInst(ReturnInst &RI);
264 void visitCallSite(CallSite CS);
265 void visitPHINode(PHINode &PN);
266 void visitExtractElementInst(ExtractElementInst &I);
267 void visitInsertElementInst(InsertElementInst &I);
268 void visitShuffleVectorInst(ShuffleVectorInst &I);
269 void visitExtractValueInst(ExtractValueInst &I);
270 void visitInsertValueInst(InsertValueInst &I);
271 void visitAllocaInst(AllocaInst &I);
272 void visitSelectInst(SelectInst &I);
273 void visitMemSetInst(MemSetInst &I);
274 void visitMemTransferInst(MemTransferInst &I);
279 char DataFlowSanitizer::ID;
280 INITIALIZE_PASS(DataFlowSanitizer, "dfsan",
281 "DataFlowSanitizer: dynamic data flow analysis.", false, false)
283 ModulePass *llvm::createDataFlowSanitizerPass(StringRef ABIListFile,
284 void *(*getArgTLS)(),
285 void *(*getRetValTLS)()) {
286 return new DataFlowSanitizer(ABIListFile, getArgTLS, getRetValTLS);
289 DataFlowSanitizer::DataFlowSanitizer(StringRef ABIListFile,
290 void *(*getArgTLS)(),
291 void *(*getRetValTLS)())
292 : ModulePass(ID), GetArgTLSPtr(getArgTLS), GetRetvalTLSPtr(getRetValTLS),
293 ABIList(SpecialCaseList::createOrDie(ABIListFile.empty() ? ClABIListFile
297 FunctionType *DataFlowSanitizer::getArgsFunctionType(FunctionType *T) {
298 llvm::SmallVector<Type *, 4> ArgTypes;
299 std::copy(T->param_begin(), T->param_end(), std::back_inserter(ArgTypes));
300 for (unsigned i = 0, e = T->getNumParams(); i != e; ++i)
301 ArgTypes.push_back(ShadowTy);
303 ArgTypes.push_back(ShadowPtrTy);
304 Type *RetType = T->getReturnType();
305 if (!RetType->isVoidTy())
306 RetType = StructType::get(RetType, ShadowTy, (Type *)0);
307 return FunctionType::get(RetType, ArgTypes, T->isVarArg());
310 FunctionType *DataFlowSanitizer::getTrampolineFunctionType(FunctionType *T) {
311 assert(!T->isVarArg());
312 llvm::SmallVector<Type *, 4> ArgTypes;
313 ArgTypes.push_back(T->getPointerTo());
314 std::copy(T->param_begin(), T->param_end(), std::back_inserter(ArgTypes));
315 for (unsigned i = 0, e = T->getNumParams(); i != e; ++i)
316 ArgTypes.push_back(ShadowTy);
317 Type *RetType = T->getReturnType();
318 if (!RetType->isVoidTy())
319 ArgTypes.push_back(ShadowPtrTy);
320 return FunctionType::get(T->getReturnType(), ArgTypes, false);
323 FunctionType *DataFlowSanitizer::getCustomFunctionType(FunctionType *T) {
324 assert(!T->isVarArg());
325 llvm::SmallVector<Type *, 4> ArgTypes;
326 for (FunctionType::param_iterator i = T->param_begin(), e = T->param_end();
329 if (isa<PointerType>(*i) && (FT = dyn_cast<FunctionType>(cast<PointerType>(
330 *i)->getElementType()))) {
331 ArgTypes.push_back(getTrampolineFunctionType(FT)->getPointerTo());
332 ArgTypes.push_back(Type::getInt8PtrTy(*Ctx));
334 ArgTypes.push_back(*i);
337 for (unsigned i = 0, e = T->getNumParams(); i != e; ++i)
338 ArgTypes.push_back(ShadowTy);
339 Type *RetType = T->getReturnType();
340 if (!RetType->isVoidTy())
341 ArgTypes.push_back(ShadowPtrTy);
342 return FunctionType::get(T->getReturnType(), ArgTypes, false);
345 bool DataFlowSanitizer::doInitialization(Module &M) {
346 DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
349 DL = &DLP->getDataLayout();
352 Ctx = &M.getContext();
353 ShadowTy = IntegerType::get(*Ctx, ShadowWidth);
354 ShadowPtrTy = PointerType::getUnqual(ShadowTy);
355 IntptrTy = DL->getIntPtrType(*Ctx);
356 ZeroShadow = ConstantInt::getSigned(ShadowTy, 0);
357 ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
358 ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidth / 8);
360 Type *DFSanUnionArgs[2] = { ShadowTy, ShadowTy };
362 FunctionType::get(ShadowTy, DFSanUnionArgs, /*isVarArg=*/ false);
363 Type *DFSanUnionLoadArgs[2] = { ShadowPtrTy, IntptrTy };
365 FunctionType::get(ShadowTy, DFSanUnionLoadArgs, /*isVarArg=*/ false);
366 DFSanUnimplementedFnTy = FunctionType::get(
367 Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
368 Type *DFSanSetLabelArgs[3] = { ShadowTy, Type::getInt8PtrTy(*Ctx), IntptrTy };
369 DFSanSetLabelFnTy = FunctionType::get(Type::getVoidTy(*Ctx),
370 DFSanSetLabelArgs, /*isVarArg=*/false);
371 DFSanNonzeroLabelFnTy = FunctionType::get(
372 Type::getVoidTy(*Ctx), ArrayRef<Type *>(), /*isVarArg=*/false);
375 Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
377 GetArgTLS = ConstantExpr::getIntToPtr(
378 ConstantInt::get(IntptrTy, uintptr_t(GetArgTLSPtr)),
379 PointerType::getUnqual(
380 FunctionType::get(PointerType::getUnqual(ArgTLSTy), (Type *)0)));
382 if (GetRetvalTLSPtr) {
384 GetRetvalTLS = ConstantExpr::getIntToPtr(
385 ConstantInt::get(IntptrTy, uintptr_t(GetRetvalTLSPtr)),
386 PointerType::getUnqual(
387 FunctionType::get(PointerType::getUnqual(ShadowTy), (Type *)0)));
390 ColdCallWeights = MDBuilder(*Ctx).createBranchWeights(1, 1000);
394 bool DataFlowSanitizer::isInstrumented(const Function *F) {
395 return !ABIList->isIn(*F, "uninstrumented");
398 bool DataFlowSanitizer::isInstrumented(const GlobalAlias *GA) {
399 return !ABIList->isIn(*GA, "uninstrumented");
402 DataFlowSanitizer::InstrumentedABI DataFlowSanitizer::getInstrumentedABI() {
403 return ClArgsABI ? IA_Args : IA_TLS;
406 DataFlowSanitizer::WrapperKind DataFlowSanitizer::getWrapperKind(Function *F) {
407 if (ABIList->isIn(*F, "functional"))
408 return WK_Functional;
409 if (ABIList->isIn(*F, "discard"))
411 if (ABIList->isIn(*F, "custom"))
417 void DataFlowSanitizer::addGlobalNamePrefix(GlobalValue *GV) {
418 std::string GVName = GV->getName(), Prefix = "dfs$";
419 GV->setName(Prefix + GVName);
421 // Try to change the name of the function in module inline asm. We only do
422 // this for specific asm directives, currently only ".symver", to try to avoid
423 // corrupting asm which happens to contain the symbol name as a substring.
424 // Note that the substitution for .symver assumes that the versioned symbol
425 // also has an instrumented name.
426 std::string Asm = GV->getParent()->getModuleInlineAsm();
427 std::string SearchStr = ".symver " + GVName + ",";
428 size_t Pos = Asm.find(SearchStr);
429 if (Pos != std::string::npos) {
430 Asm.replace(Pos, SearchStr.size(),
431 ".symver " + Prefix + GVName + "," + Prefix);
432 GV->getParent()->setModuleInlineAsm(Asm);
437 DataFlowSanitizer::buildWrapperFunction(Function *F, StringRef NewFName,
438 GlobalValue::LinkageTypes NewFLink,
439 FunctionType *NewFT) {
440 FunctionType *FT = F->getFunctionType();
441 Function *NewF = Function::Create(NewFT, NewFLink, NewFName,
443 NewF->copyAttributesFrom(F);
444 NewF->removeAttributes(
445 AttributeSet::ReturnIndex,
446 AttributeFuncs::typeIncompatible(NewFT->getReturnType(),
447 AttributeSet::ReturnIndex));
449 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", NewF);
450 std::vector<Value *> Args;
451 unsigned n = FT->getNumParams();
452 for (Function::arg_iterator ai = NewF->arg_begin(); n != 0; ++ai, --n)
453 Args.push_back(&*ai);
454 CallInst *CI = CallInst::Create(F, Args, "", BB);
455 if (FT->getReturnType()->isVoidTy())
456 ReturnInst::Create(*Ctx, BB);
458 ReturnInst::Create(*Ctx, CI, BB);
463 Constant *DataFlowSanitizer::getOrBuildTrampolineFunction(FunctionType *FT,
465 FunctionType *FTT = getTrampolineFunctionType(FT);
466 Constant *C = Mod->getOrInsertFunction(FName, FTT);
467 Function *F = dyn_cast<Function>(C);
468 if (F && F->isDeclaration()) {
469 F->setLinkage(GlobalValue::LinkOnceODRLinkage);
470 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
471 std::vector<Value *> Args;
472 Function::arg_iterator AI = F->arg_begin(); ++AI;
473 for (unsigned N = FT->getNumParams(); N != 0; ++AI, --N)
474 Args.push_back(&*AI);
476 CallInst::Create(&F->getArgumentList().front(), Args, "", BB);
478 if (FT->getReturnType()->isVoidTy())
479 RI = ReturnInst::Create(*Ctx, BB);
481 RI = ReturnInst::Create(*Ctx, CI, BB);
483 DFSanFunction DFSF(*this, F, /*IsNativeABI=*/true);
484 Function::arg_iterator ValAI = F->arg_begin(), ShadowAI = AI; ++ValAI;
485 for (unsigned N = FT->getNumParams(); N != 0; ++ValAI, ++ShadowAI, --N)
486 DFSF.ValShadowMap[ValAI] = ShadowAI;
487 DFSanVisitor(DFSF).visitCallInst(*CI);
488 if (!FT->getReturnType()->isVoidTy())
489 new StoreInst(DFSF.getShadow(RI->getReturnValue()),
490 &F->getArgumentList().back(), RI);
496 bool DataFlowSanitizer::runOnModule(Module &M) {
500 if (ABIList->isIn(M, "skip"))
504 Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
505 ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
506 if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS))
507 G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
509 if (!GetRetvalTLSPtr) {
510 RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", ShadowTy);
511 if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS))
512 G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
515 DFSanUnionFn = Mod->getOrInsertFunction("__dfsan_union", DFSanUnionFnTy);
516 if (Function *F = dyn_cast<Function>(DFSanUnionFn)) {
517 F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
518 F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
519 F->addAttribute(1, Attribute::ZExt);
520 F->addAttribute(2, Attribute::ZExt);
523 Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
524 if (Function *F = dyn_cast<Function>(DFSanUnionLoadFn)) {
525 F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadOnly);
526 F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
528 DFSanUnimplementedFn =
529 Mod->getOrInsertFunction("__dfsan_unimplemented", DFSanUnimplementedFnTy);
531 Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy);
532 if (Function *F = dyn_cast<Function>(DFSanSetLabelFn)) {
533 F->addAttribute(1, Attribute::ZExt);
535 DFSanNonzeroLabelFn =
536 Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
538 std::vector<Function *> FnsToInstrument;
539 llvm::SmallPtrSet<Function *, 2> FnsWithNativeABI;
540 for (Module::iterator i = M.begin(), e = M.end(); i != e; ++i) {
541 if (!i->isIntrinsic() &&
543 i != DFSanUnionLoadFn &&
544 i != DFSanUnimplementedFn &&
545 i != DFSanSetLabelFn &&
546 i != DFSanNonzeroLabelFn)
547 FnsToInstrument.push_back(&*i);
550 // Give function aliases prefixes when necessary, and build wrappers where the
551 // instrumentedness is inconsistent.
552 for (Module::alias_iterator i = M.alias_begin(), e = M.alias_end(); i != e;) {
553 GlobalAlias *GA = &*i;
555 // Don't stop on weak. We assume people aren't playing games with the
556 // instrumentedness of overridden weak aliases.
557 if (Function *F = dyn_cast<Function>(
558 GA->resolveAliasedGlobal(/*stopOnWeak=*/false))) {
559 bool GAInst = isInstrumented(GA), FInst = isInstrumented(F);
560 if (GAInst && FInst) {
561 addGlobalNamePrefix(GA);
562 } else if (GAInst != FInst) {
563 // Non-instrumented alias of an instrumented function, or vice versa.
564 // Replace the alias with a native-ABI wrapper of the aliasee. The pass
565 // below will take care of instrumenting it.
567 buildWrapperFunction(F, "", GA->getLinkage(), F->getFunctionType());
568 GA->replaceAllUsesWith(NewF);
570 GA->eraseFromParent();
571 FnsToInstrument.push_back(NewF);
577 B.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
578 ReadOnlyNoneAttrs = AttributeSet::get(*Ctx, AttributeSet::FunctionIndex, B);
580 // First, change the ABI of every function in the module. ABI-listed
581 // functions keep their original ABI and get a wrapper function.
582 for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
583 e = FnsToInstrument.end();
586 FunctionType *FT = F.getFunctionType();
588 bool IsZeroArgsVoidRet = (FT->getNumParams() == 0 && !FT->isVarArg() &&
589 FT->getReturnType()->isVoidTy());
591 if (isInstrumented(&F)) {
592 // Instrumented functions get a 'dfs$' prefix. This allows us to more
593 // easily identify cases of mismatching ABIs.
594 if (getInstrumentedABI() == IA_Args && !IsZeroArgsVoidRet) {
595 FunctionType *NewFT = getArgsFunctionType(FT);
596 Function *NewF = Function::Create(NewFT, F.getLinkage(), "", &M);
597 NewF->copyAttributesFrom(&F);
598 NewF->removeAttributes(
599 AttributeSet::ReturnIndex,
600 AttributeFuncs::typeIncompatible(NewFT->getReturnType(),
601 AttributeSet::ReturnIndex));
602 for (Function::arg_iterator FArg = F.arg_begin(),
603 NewFArg = NewF->arg_begin(),
604 FArgEnd = F.arg_end();
605 FArg != FArgEnd; ++FArg, ++NewFArg) {
606 FArg->replaceAllUsesWith(NewFArg);
608 NewF->getBasicBlockList().splice(NewF->begin(), F.getBasicBlockList());
610 for (Function::use_iterator ui = F.use_begin(), ue = F.use_end();
612 BlockAddress *BA = dyn_cast<BlockAddress>(ui.getUse().getUser());
615 BA->replaceAllUsesWith(
616 BlockAddress::get(NewF, BA->getBasicBlock()));
620 F.replaceAllUsesWith(
621 ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT)));
625 addGlobalNamePrefix(NewF);
627 addGlobalNamePrefix(&F);
629 // Hopefully, nobody will try to indirectly call a vararg
631 } else if (FT->isVarArg()) {
632 UnwrappedFnMap[&F] = &F;
634 } else if (!IsZeroArgsVoidRet || getWrapperKind(&F) == WK_Custom) {
635 // Build a wrapper function for F. The wrapper simply calls F, and is
636 // added to FnsToInstrument so that any instrumentation according to its
637 // WrapperKind is done in the second pass below.
638 FunctionType *NewFT = getInstrumentedABI() == IA_Args
639 ? getArgsFunctionType(FT)
641 Function *NewF = buildWrapperFunction(
642 &F, std::string("dfsw$") + std::string(F.getName()),
643 GlobalValue::LinkOnceODRLinkage, NewFT);
644 if (getInstrumentedABI() == IA_TLS)
645 NewF->removeAttributes(AttributeSet::FunctionIndex, ReadOnlyNoneAttrs);
647 Value *WrappedFnCst =
648 ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT));
649 F.replaceAllUsesWith(WrappedFnCst);
650 UnwrappedFnMap[WrappedFnCst] = &F;
653 if (!F.isDeclaration()) {
654 // This function is probably defining an interposition of an
655 // uninstrumented function and hence needs to keep the original ABI.
656 // But any functions it may call need to use the instrumented ABI, so
657 // we instrument it in a mode which preserves the original ABI.
658 FnsWithNativeABI.insert(&F);
660 // This code needs to rebuild the iterators, as they may be invalidated
661 // by the push_back, taking care that the new range does not include
662 // any functions added by this code.
663 size_t N = i - FnsToInstrument.begin(),
664 Count = e - FnsToInstrument.begin();
665 FnsToInstrument.push_back(&F);
666 i = FnsToInstrument.begin() + N;
667 e = FnsToInstrument.begin() + Count;
672 for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
673 e = FnsToInstrument.end();
675 if (!*i || (*i)->isDeclaration())
678 removeUnreachableBlocks(**i);
680 DFSanFunction DFSF(*this, *i, FnsWithNativeABI.count(*i));
682 // DFSanVisitor may create new basic blocks, which confuses df_iterator.
683 // Build a copy of the list before iterating over it.
684 llvm::SmallVector<BasicBlock *, 4> BBList;
685 std::copy(df_begin(&(*i)->getEntryBlock()), df_end(&(*i)->getEntryBlock()),
686 std::back_inserter(BBList));
688 for (llvm::SmallVector<BasicBlock *, 4>::iterator i = BBList.begin(),
691 Instruction *Inst = &(*i)->front();
693 // DFSanVisitor may split the current basic block, changing the current
694 // instruction's next pointer and moving the next instruction to the
695 // tail block from which we should continue.
696 Instruction *Next = Inst->getNextNode();
697 // DFSanVisitor may delete Inst, so keep track of whether it was a
699 bool IsTerminator = isa<TerminatorInst>(Inst);
700 if (!DFSF.SkipInsts.count(Inst))
701 DFSanVisitor(DFSF).visit(Inst);
708 // We will not necessarily be able to compute the shadow for every phi node
709 // until we have visited every block. Therefore, the code that handles phi
710 // nodes adds them to the PHIFixups list so that they can be properly
712 for (std::vector<std::pair<PHINode *, PHINode *> >::iterator
713 i = DFSF.PHIFixups.begin(),
714 e = DFSF.PHIFixups.end();
716 for (unsigned val = 0, n = i->first->getNumIncomingValues(); val != n;
718 i->second->setIncomingValue(
719 val, DFSF.getShadow(i->first->getIncomingValue(val)));
723 // -dfsan-debug-nonzero-labels will split the CFG in all kinds of crazy
724 // places (i.e. instructions in basic blocks we haven't even begun visiting
725 // yet). To make our life easier, do this work in a pass after the main
727 if (ClDebugNonzeroLabels) {
728 for (DenseSet<Value *>::iterator i = DFSF.NonZeroChecks.begin(),
729 e = DFSF.NonZeroChecks.end();
732 if (Instruction *I = dyn_cast<Instruction>(*i))
733 Pos = I->getNextNode();
735 Pos = DFSF.F->getEntryBlock().begin();
736 while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
737 Pos = Pos->getNextNode();
738 IRBuilder<> IRB(Pos);
739 Value *Ne = IRB.CreateICmpNE(*i, DFSF.DFS.ZeroShadow);
740 BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
741 Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
742 IRBuilder<> ThenIRB(BI);
743 ThenIRB.CreateCall(DFSF.DFS.DFSanNonzeroLabelFn);
751 Value *DFSanFunction::getArgTLSPtr() {
755 return ArgTLSPtr = DFS.ArgTLS;
757 IRBuilder<> IRB(F->getEntryBlock().begin());
758 return ArgTLSPtr = IRB.CreateCall(DFS.GetArgTLS);
761 Value *DFSanFunction::getRetvalTLS() {
765 return RetvalTLSPtr = DFS.RetvalTLS;
767 IRBuilder<> IRB(F->getEntryBlock().begin());
768 return RetvalTLSPtr = IRB.CreateCall(DFS.GetRetvalTLS);
771 Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
772 IRBuilder<> IRB(Pos);
773 return IRB.CreateConstGEP2_64(getArgTLSPtr(), 0, Idx);
776 Value *DFSanFunction::getShadow(Value *V) {
777 if (!isa<Argument>(V) && !isa<Instruction>(V))
778 return DFS.ZeroShadow;
779 Value *&Shadow = ValShadowMap[V];
781 if (Argument *A = dyn_cast<Argument>(V)) {
783 return DFS.ZeroShadow;
785 case DataFlowSanitizer::IA_TLS: {
786 Value *ArgTLSPtr = getArgTLSPtr();
787 Instruction *ArgTLSPos =
788 DFS.ArgTLS ? &*F->getEntryBlock().begin()
789 : cast<Instruction>(ArgTLSPtr)->getNextNode();
790 IRBuilder<> IRB(ArgTLSPos);
791 Shadow = IRB.CreateLoad(getArgTLS(A->getArgNo(), ArgTLSPos));
794 case DataFlowSanitizer::IA_Args: {
795 unsigned ArgIdx = A->getArgNo() + F->getArgumentList().size() / 2;
796 Function::arg_iterator i = F->arg_begin();
800 assert(Shadow->getType() == DFS.ShadowTy);
804 NonZeroChecks.insert(Shadow);
806 Shadow = DFS.ZeroShadow;
812 void DFSanFunction::setShadow(Instruction *I, Value *Shadow) {
813 assert(!ValShadowMap.count(I));
814 assert(Shadow->getType() == DFS.ShadowTy);
815 ValShadowMap[I] = Shadow;
818 Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
819 assert(Addr != RetvalTLS && "Reinstrumenting?");
820 IRBuilder<> IRB(Pos);
821 return IRB.CreateIntToPtr(
823 IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy), ShadowPtrMask),
828 // Generates IR to compute the union of the two given shadows, inserting it
829 // before Pos. Returns the computed union Value.
830 Value *DataFlowSanitizer::combineShadows(Value *V1, Value *V2,
832 if (V1 == ZeroShadow)
834 if (V2 == ZeroShadow)
838 IRBuilder<> IRB(Pos);
839 BasicBlock *Head = Pos->getParent();
840 Value *Ne = IRB.CreateICmpNE(V1, V2);
841 BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
842 Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
843 IRBuilder<> ThenIRB(BI);
844 CallInst *Call = ThenIRB.CreateCall2(DFSanUnionFn, V1, V2);
845 Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
846 Call->addAttribute(1, Attribute::ZExt);
847 Call->addAttribute(2, Attribute::ZExt);
849 BasicBlock *Tail = BI->getSuccessor(0);
850 PHINode *Phi = PHINode::Create(ShadowTy, 2, "", Tail->begin());
851 Phi->addIncoming(Call, Call->getParent());
852 Phi->addIncoming(V1, Head);
857 // A convenience function which folds the shadows of each of the operands
858 // of the provided instruction Inst, inserting the IR before Inst. Returns
859 // the computed union Value.
860 Value *DFSanFunction::combineOperandShadows(Instruction *Inst) {
861 if (Inst->getNumOperands() == 0)
862 return DFS.ZeroShadow;
864 Value *Shadow = getShadow(Inst->getOperand(0));
865 for (unsigned i = 1, n = Inst->getNumOperands(); i != n; ++i) {
866 Shadow = DFS.combineShadows(Shadow, getShadow(Inst->getOperand(i)), Inst);
871 void DFSanVisitor::visitOperandShadowInst(Instruction &I) {
872 Value *CombinedShadow = DFSF.combineOperandShadows(&I);
873 DFSF.setShadow(&I, CombinedShadow);
876 // Generates IR to load shadow corresponding to bytes [Addr, Addr+Size), where
877 // Addr has alignment Align, and take the union of each of those shadows.
878 Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
880 if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
881 llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
882 AllocaShadowMap.find(AI);
883 if (i != AllocaShadowMap.end()) {
884 IRBuilder<> IRB(Pos);
885 return IRB.CreateLoad(i->second);
889 uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
890 SmallVector<Value *, 2> Objs;
891 GetUnderlyingObjects(Addr, Objs, DFS.DL);
892 bool AllConstants = true;
893 for (SmallVector<Value *, 2>::iterator i = Objs.begin(), e = Objs.end();
895 if (isa<Function>(*i) || isa<BlockAddress>(*i))
897 if (isa<GlobalVariable>(*i) && cast<GlobalVariable>(*i)->isConstant())
900 AllConstants = false;
904 return DFS.ZeroShadow;
906 Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
909 return DFS.ZeroShadow;
911 LoadInst *LI = new LoadInst(ShadowAddr, "", Pos);
912 LI->setAlignment(ShadowAlign);
916 IRBuilder<> IRB(Pos);
918 IRB.CreateGEP(ShadowAddr, ConstantInt::get(DFS.IntptrTy, 1));
919 return DFS.combineShadows(IRB.CreateAlignedLoad(ShadowAddr, ShadowAlign),
920 IRB.CreateAlignedLoad(ShadowAddr1, ShadowAlign),
924 if (Size % (64 / DFS.ShadowWidth) == 0) {
925 // Fast path for the common case where each byte has identical shadow: load
926 // shadow 64 bits at a time, fall out to a __dfsan_union_load call if any
927 // shadow is non-equal.
928 BasicBlock *FallbackBB = BasicBlock::Create(*DFS.Ctx, "", F);
929 IRBuilder<> FallbackIRB(FallbackBB);
930 CallInst *FallbackCall = FallbackIRB.CreateCall2(
931 DFS.DFSanUnionLoadFn, ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size));
932 FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
934 // Compare each of the shadows stored in the loaded 64 bits to each other,
935 // by computing (WideShadow rotl ShadowWidth) == WideShadow.
936 IRBuilder<> IRB(Pos);
938 IRB.CreateBitCast(ShadowAddr, Type::getInt64PtrTy(*DFS.Ctx));
939 Value *WideShadow = IRB.CreateAlignedLoad(WideAddr, ShadowAlign);
940 Value *TruncShadow = IRB.CreateTrunc(WideShadow, DFS.ShadowTy);
941 Value *ShlShadow = IRB.CreateShl(WideShadow, DFS.ShadowWidth);
942 Value *ShrShadow = IRB.CreateLShr(WideShadow, 64 - DFS.ShadowWidth);
943 Value *RotShadow = IRB.CreateOr(ShlShadow, ShrShadow);
944 Value *ShadowsEq = IRB.CreateICmpEQ(WideShadow, RotShadow);
946 BasicBlock *Head = Pos->getParent();
947 BasicBlock *Tail = Head->splitBasicBlock(Pos);
948 // In the following code LastBr will refer to the previous basic block's
949 // conditional branch instruction, whose true successor is fixed up to point
950 // to the next block during the loop below or to the tail after the final
952 BranchInst *LastBr = BranchInst::Create(FallbackBB, FallbackBB, ShadowsEq);
953 ReplaceInstWithInst(Head->getTerminator(), LastBr);
955 for (uint64_t Ofs = 64 / DFS.ShadowWidth; Ofs != Size;
956 Ofs += 64 / DFS.ShadowWidth) {
957 BasicBlock *NextBB = BasicBlock::Create(*DFS.Ctx, "", F);
958 IRBuilder<> NextIRB(NextBB);
959 WideAddr = NextIRB.CreateGEP(WideAddr, ConstantInt::get(DFS.IntptrTy, 1));
960 Value *NextWideShadow = NextIRB.CreateAlignedLoad(WideAddr, ShadowAlign);
961 ShadowsEq = NextIRB.CreateICmpEQ(WideShadow, NextWideShadow);
962 LastBr->setSuccessor(0, NextBB);
963 LastBr = NextIRB.CreateCondBr(ShadowsEq, FallbackBB, FallbackBB);
966 LastBr->setSuccessor(0, Tail);
967 FallbackIRB.CreateBr(Tail);
968 PHINode *Shadow = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
969 Shadow->addIncoming(FallbackCall, FallbackBB);
970 Shadow->addIncoming(TruncShadow, LastBr->getParent());
974 IRBuilder<> IRB(Pos);
975 CallInst *FallbackCall = IRB.CreateCall2(
976 DFS.DFSanUnionLoadFn, ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size));
977 FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
981 void DFSanVisitor::visitLoadInst(LoadInst &LI) {
982 uint64_t Size = DFSF.DFS.DL->getTypeStoreSize(LI.getType());
984 if (ClPreserveAlignment) {
985 Align = LI.getAlignment();
987 Align = DFSF.DFS.DL->getABITypeAlignment(LI.getType());
991 IRBuilder<> IRB(&LI);
992 Value *Shadow = DFSF.loadShadow(LI.getPointerOperand(), Size, Align, &LI);
993 if (ClCombinePointerLabelsOnLoad) {
994 Value *PtrShadow = DFSF.getShadow(LI.getPointerOperand());
995 Shadow = DFSF.DFS.combineShadows(Shadow, PtrShadow, &LI);
997 if (Shadow != DFSF.DFS.ZeroShadow)
998 DFSF.NonZeroChecks.insert(Shadow);
1000 DFSF.setShadow(&LI, Shadow);
1003 void DFSanFunction::storeShadow(Value *Addr, uint64_t Size, uint64_t Align,
1004 Value *Shadow, Instruction *Pos) {
1005 if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
1006 llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
1007 AllocaShadowMap.find(AI);
1008 if (i != AllocaShadowMap.end()) {
1009 IRBuilder<> IRB(Pos);
1010 IRB.CreateStore(Shadow, i->second);
1015 uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
1016 IRBuilder<> IRB(Pos);
1017 Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
1018 if (Shadow == DFS.ZeroShadow) {
1019 IntegerType *ShadowTy = IntegerType::get(*DFS.Ctx, Size * DFS.ShadowWidth);
1020 Value *ExtZeroShadow = ConstantInt::get(ShadowTy, 0);
1021 Value *ExtShadowAddr =
1022 IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowTy));
1023 IRB.CreateAlignedStore(ExtZeroShadow, ExtShadowAddr, ShadowAlign);
1027 const unsigned ShadowVecSize = 128 / DFS.ShadowWidth;
1028 uint64_t Offset = 0;
1029 if (Size >= ShadowVecSize) {
1030 VectorType *ShadowVecTy = VectorType::get(DFS.ShadowTy, ShadowVecSize);
1031 Value *ShadowVec = UndefValue::get(ShadowVecTy);
1032 for (unsigned i = 0; i != ShadowVecSize; ++i) {
1033 ShadowVec = IRB.CreateInsertElement(
1034 ShadowVec, Shadow, ConstantInt::get(Type::getInt32Ty(*DFS.Ctx), i));
1036 Value *ShadowVecAddr =
1037 IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowVecTy));
1039 Value *CurShadowVecAddr = IRB.CreateConstGEP1_32(ShadowVecAddr, Offset);
1040 IRB.CreateAlignedStore(ShadowVec, CurShadowVecAddr, ShadowAlign);
1041 Size -= ShadowVecSize;
1043 } while (Size >= ShadowVecSize);
1044 Offset *= ShadowVecSize;
1047 Value *CurShadowAddr = IRB.CreateConstGEP1_32(ShadowAddr, Offset);
1048 IRB.CreateAlignedStore(Shadow, CurShadowAddr, ShadowAlign);
1054 void DFSanVisitor::visitStoreInst(StoreInst &SI) {
1056 DFSF.DFS.DL->getTypeStoreSize(SI.getValueOperand()->getType());
1058 if (ClPreserveAlignment) {
1059 Align = SI.getAlignment();
1061 Align = DFSF.DFS.DL->getABITypeAlignment(SI.getValueOperand()->getType());
1066 Value* Shadow = DFSF.getShadow(SI.getValueOperand());
1067 if (ClCombinePointerLabelsOnStore) {
1068 Value *PtrShadow = DFSF.getShadow(SI.getPointerOperand());
1069 Shadow = DFSF.DFS.combineShadows(Shadow, PtrShadow, &SI);
1071 DFSF.storeShadow(SI.getPointerOperand(), Size, Align, Shadow, &SI);
1074 void DFSanVisitor::visitBinaryOperator(BinaryOperator &BO) {
1075 visitOperandShadowInst(BO);
1078 void DFSanVisitor::visitCastInst(CastInst &CI) { visitOperandShadowInst(CI); }
1080 void DFSanVisitor::visitCmpInst(CmpInst &CI) { visitOperandShadowInst(CI); }
1082 void DFSanVisitor::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
1083 visitOperandShadowInst(GEPI);
1086 void DFSanVisitor::visitExtractElementInst(ExtractElementInst &I) {
1087 visitOperandShadowInst(I);
1090 void DFSanVisitor::visitInsertElementInst(InsertElementInst &I) {
1091 visitOperandShadowInst(I);
1094 void DFSanVisitor::visitShuffleVectorInst(ShuffleVectorInst &I) {
1095 visitOperandShadowInst(I);
1098 void DFSanVisitor::visitExtractValueInst(ExtractValueInst &I) {
1099 visitOperandShadowInst(I);
1102 void DFSanVisitor::visitInsertValueInst(InsertValueInst &I) {
1103 visitOperandShadowInst(I);
1106 void DFSanVisitor::visitAllocaInst(AllocaInst &I) {
1107 bool AllLoadsStores = true;
1108 for (Instruction::use_iterator i = I.use_begin(), e = I.use_end(); i != e;
1110 if (isa<LoadInst>(*i))
1113 if (StoreInst *SI = dyn_cast<StoreInst>(*i)) {
1114 if (SI->getPointerOperand() == &I)
1118 AllLoadsStores = false;
1121 if (AllLoadsStores) {
1122 IRBuilder<> IRB(&I);
1123 DFSF.AllocaShadowMap[&I] = IRB.CreateAlloca(DFSF.DFS.ShadowTy);
1125 DFSF.setShadow(&I, DFSF.DFS.ZeroShadow);
1128 void DFSanVisitor::visitSelectInst(SelectInst &I) {
1129 Value *CondShadow = DFSF.getShadow(I.getCondition());
1130 Value *TrueShadow = DFSF.getShadow(I.getTrueValue());
1131 Value *FalseShadow = DFSF.getShadow(I.getFalseValue());
1133 if (isa<VectorType>(I.getCondition()->getType())) {
1135 &I, DFSF.DFS.combineShadows(
1137 DFSF.DFS.combineShadows(TrueShadow, FalseShadow, &I), &I));
1140 if (TrueShadow == FalseShadow) {
1141 ShadowSel = TrueShadow;
1144 SelectInst::Create(I.getCondition(), TrueShadow, FalseShadow, "", &I);
1146 DFSF.setShadow(&I, DFSF.DFS.combineShadows(CondShadow, ShadowSel, &I));
1150 void DFSanVisitor::visitMemSetInst(MemSetInst &I) {
1151 IRBuilder<> IRB(&I);
1152 Value *ValShadow = DFSF.getShadow(I.getValue());
1154 DFSF.DFS.DFSanSetLabelFn, ValShadow,
1155 IRB.CreateBitCast(I.getDest(), Type::getInt8PtrTy(*DFSF.DFS.Ctx)),
1156 IRB.CreateZExtOrTrunc(I.getLength(), DFSF.DFS.IntptrTy));
1159 void DFSanVisitor::visitMemTransferInst(MemTransferInst &I) {
1160 IRBuilder<> IRB(&I);
1161 Value *DestShadow = DFSF.DFS.getShadowAddress(I.getDest(), &I);
1162 Value *SrcShadow = DFSF.DFS.getShadowAddress(I.getSource(), &I);
1163 Value *LenShadow = IRB.CreateMul(
1165 ConstantInt::get(I.getLength()->getType(), DFSF.DFS.ShadowWidth / 8));
1167 if (ClPreserveAlignment) {
1168 AlignShadow = IRB.CreateMul(I.getAlignmentCst(),
1169 ConstantInt::get(I.getAlignmentCst()->getType(),
1170 DFSF.DFS.ShadowWidth / 8));
1172 AlignShadow = ConstantInt::get(I.getAlignmentCst()->getType(),
1173 DFSF.DFS.ShadowWidth / 8);
1175 Type *Int8Ptr = Type::getInt8PtrTy(*DFSF.DFS.Ctx);
1176 DestShadow = IRB.CreateBitCast(DestShadow, Int8Ptr);
1177 SrcShadow = IRB.CreateBitCast(SrcShadow, Int8Ptr);
1178 IRB.CreateCall5(I.getCalledValue(), DestShadow, SrcShadow, LenShadow,
1179 AlignShadow, I.getVolatileCst());
1182 void DFSanVisitor::visitReturnInst(ReturnInst &RI) {
1183 if (!DFSF.IsNativeABI && RI.getReturnValue()) {
1185 case DataFlowSanitizer::IA_TLS: {
1186 Value *S = DFSF.getShadow(RI.getReturnValue());
1187 IRBuilder<> IRB(&RI);
1188 IRB.CreateStore(S, DFSF.getRetvalTLS());
1191 case DataFlowSanitizer::IA_Args: {
1192 IRBuilder<> IRB(&RI);
1193 Type *RT = DFSF.F->getFunctionType()->getReturnType();
1195 IRB.CreateInsertValue(UndefValue::get(RT), RI.getReturnValue(), 0);
1197 IRB.CreateInsertValue(InsVal, DFSF.getShadow(RI.getReturnValue()), 1);
1198 RI.setOperand(0, InsShadow);
1205 void DFSanVisitor::visitCallSite(CallSite CS) {
1206 Function *F = CS.getCalledFunction();
1207 if ((F && F->isIntrinsic()) || isa<InlineAsm>(CS.getCalledValue())) {
1208 visitOperandShadowInst(*CS.getInstruction());
1212 IRBuilder<> IRB(CS.getInstruction());
1214 DenseMap<Value *, Function *>::iterator i =
1215 DFSF.DFS.UnwrappedFnMap.find(CS.getCalledValue());
1216 if (i != DFSF.DFS.UnwrappedFnMap.end()) {
1217 Function *F = i->second;
1218 switch (DFSF.DFS.getWrapperKind(F)) {
1219 case DataFlowSanitizer::WK_Warning: {
1220 CS.setCalledFunction(F);
1221 IRB.CreateCall(DFSF.DFS.DFSanUnimplementedFn,
1222 IRB.CreateGlobalStringPtr(F->getName()));
1223 DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1226 case DataFlowSanitizer::WK_Discard: {
1227 CS.setCalledFunction(F);
1228 DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1231 case DataFlowSanitizer::WK_Functional: {
1232 CS.setCalledFunction(F);
1233 visitOperandShadowInst(*CS.getInstruction());
1236 case DataFlowSanitizer::WK_Custom: {
1237 // Don't try to handle invokes of custom functions, it's too complicated.
1238 // Instead, invoke the dfsw$ wrapper, which will in turn call the __dfsw_
1240 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) {
1241 FunctionType *FT = F->getFunctionType();
1242 FunctionType *CustomFT = DFSF.DFS.getCustomFunctionType(FT);
1243 std::string CustomFName = "__dfsw_";
1244 CustomFName += F->getName();
1246 DFSF.DFS.Mod->getOrInsertFunction(CustomFName, CustomFT);
1247 if (Function *CustomFn = dyn_cast<Function>(CustomF)) {
1248 CustomFn->copyAttributesFrom(F);
1250 // Custom functions returning non-void will write to the return label.
1251 if (!FT->getReturnType()->isVoidTy()) {
1252 CustomFn->removeAttributes(AttributeSet::FunctionIndex,
1253 DFSF.DFS.ReadOnlyNoneAttrs);
1257 std::vector<Value *> Args;
1259 CallSite::arg_iterator i = CS.arg_begin();
1260 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n) {
1261 Type *T = (*i)->getType();
1262 FunctionType *ParamFT;
1263 if (isa<PointerType>(T) &&
1264 (ParamFT = dyn_cast<FunctionType>(
1265 cast<PointerType>(T)->getElementType()))) {
1266 std::string TName = "dfst";
1267 TName += utostr(FT->getNumParams() - n);
1269 TName += F->getName();
1270 Constant *T = DFSF.DFS.getOrBuildTrampolineFunction(ParamFT, TName);
1273 IRB.CreateBitCast(*i, Type::getInt8PtrTy(*DFSF.DFS.Ctx)));
1280 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1281 Args.push_back(DFSF.getShadow(*i));
1283 if (!FT->getReturnType()->isVoidTy()) {
1284 if (!DFSF.LabelReturnAlloca) {
1285 DFSF.LabelReturnAlloca =
1286 new AllocaInst(DFSF.DFS.ShadowTy, "labelreturn",
1287 DFSF.F->getEntryBlock().begin());
1289 Args.push_back(DFSF.LabelReturnAlloca);
1292 CallInst *CustomCI = IRB.CreateCall(CustomF, Args);
1293 CustomCI->setCallingConv(CI->getCallingConv());
1294 CustomCI->setAttributes(CI->getAttributes());
1296 if (!FT->getReturnType()->isVoidTy()) {
1297 LoadInst *LabelLoad = IRB.CreateLoad(DFSF.LabelReturnAlloca);
1298 DFSF.setShadow(CustomCI, LabelLoad);
1301 CI->replaceAllUsesWith(CustomCI);
1302 CI->eraseFromParent();
1310 FunctionType *FT = cast<FunctionType>(
1311 CS.getCalledValue()->getType()->getPointerElementType());
1312 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1313 for (unsigned i = 0, n = FT->getNumParams(); i != n; ++i) {
1314 IRB.CreateStore(DFSF.getShadow(CS.getArgument(i)),
1315 DFSF.getArgTLS(i, CS.getInstruction()));
1319 Instruction *Next = 0;
1320 if (!CS.getType()->isVoidTy()) {
1321 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1322 if (II->getNormalDest()->getSinglePredecessor()) {
1323 Next = II->getNormalDest()->begin();
1326 SplitEdge(II->getParent(), II->getNormalDest(), &DFSF.DFS);
1327 Next = NewBB->begin();
1330 Next = CS->getNextNode();
1333 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1334 IRBuilder<> NextIRB(Next);
1335 LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
1336 DFSF.SkipInsts.insert(LI);
1337 DFSF.setShadow(CS.getInstruction(), LI);
1338 DFSF.NonZeroChecks.insert(LI);
1342 // Do all instrumentation for IA_Args down here to defer tampering with the
1343 // CFG in a way that SplitEdge may be able to detect.
1344 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_Args) {
1345 FunctionType *NewFT = DFSF.DFS.getArgsFunctionType(FT);
1347 IRB.CreateBitCast(CS.getCalledValue(), PointerType::getUnqual(NewFT));
1348 std::vector<Value *> Args;
1350 CallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
1351 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1355 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1356 Args.push_back(DFSF.getShadow(*i));
1358 if (FT->isVarArg()) {
1359 unsigned VarArgSize = CS.arg_size() - FT->getNumParams();
1360 ArrayType *VarArgArrayTy = ArrayType::get(DFSF.DFS.ShadowTy, VarArgSize);
1361 AllocaInst *VarArgShadow =
1362 new AllocaInst(VarArgArrayTy, "", DFSF.F->getEntryBlock().begin());
1363 Args.push_back(IRB.CreateConstGEP2_32(VarArgShadow, 0, 0));
1364 for (unsigned n = 0; i != e; ++i, ++n) {
1365 IRB.CreateStore(DFSF.getShadow(*i),
1366 IRB.CreateConstGEP2_32(VarArgShadow, 0, n));
1372 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1373 NewCS = IRB.CreateInvoke(Func, II->getNormalDest(), II->getUnwindDest(),
1376 NewCS = IRB.CreateCall(Func, Args);
1378 NewCS.setCallingConv(CS.getCallingConv());
1379 NewCS.setAttributes(CS.getAttributes().removeAttributes(
1380 *DFSF.DFS.Ctx, AttributeSet::ReturnIndex,
1381 AttributeFuncs::typeIncompatible(NewCS.getInstruction()->getType(),
1382 AttributeSet::ReturnIndex)));
1385 ExtractValueInst *ExVal =
1386 ExtractValueInst::Create(NewCS.getInstruction(), 0, "", Next);
1387 DFSF.SkipInsts.insert(ExVal);
1388 ExtractValueInst *ExShadow =
1389 ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
1390 DFSF.SkipInsts.insert(ExShadow);
1391 DFSF.setShadow(ExVal, ExShadow);
1392 DFSF.NonZeroChecks.insert(ExShadow);
1394 CS.getInstruction()->replaceAllUsesWith(ExVal);
1397 CS.getInstruction()->eraseFromParent();
1401 void DFSanVisitor::visitPHINode(PHINode &PN) {
1403 PHINode::Create(DFSF.DFS.ShadowTy, PN.getNumIncomingValues(), "", &PN);
1405 // Give the shadow phi node valid predecessors to fool SplitEdge into working.
1406 Value *UndefShadow = UndefValue::get(DFSF.DFS.ShadowTy);
1407 for (PHINode::block_iterator i = PN.block_begin(), e = PN.block_end(); i != e;
1409 ShadowPN->addIncoming(UndefShadow, *i);
1412 DFSF.PHIFixups.push_back(std::make_pair(&PN, ShadowPN));
1413 DFSF.setShadow(&PN, ShadowPN);