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/InlineAsm.h"
54 #include "llvm/IR/IRBuilder.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.
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);
217 bool runOnModule(Module &M);
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 DL = getAnalysisIfAvailable<DataLayout>();
351 Ctx = &M.getContext();
352 ShadowTy = IntegerType::get(*Ctx, ShadowWidth);
353 ShadowPtrTy = PointerType::getUnqual(ShadowTy);
354 IntptrTy = DL->getIntPtrType(*Ctx);
355 ZeroShadow = ConstantInt::getSigned(ShadowTy, 0);
356 ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
357 ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidth / 8);
359 Type *DFSanUnionArgs[2] = { ShadowTy, ShadowTy };
361 FunctionType::get(ShadowTy, DFSanUnionArgs, /*isVarArg=*/ false);
362 Type *DFSanUnionLoadArgs[2] = { ShadowPtrTy, IntptrTy };
364 FunctionType::get(ShadowTy, DFSanUnionLoadArgs, /*isVarArg=*/ false);
365 DFSanUnimplementedFnTy = FunctionType::get(
366 Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
367 Type *DFSanSetLabelArgs[3] = { ShadowTy, Type::getInt8PtrTy(*Ctx), IntptrTy };
368 DFSanSetLabelFnTy = FunctionType::get(Type::getVoidTy(*Ctx),
369 DFSanSetLabelArgs, /*isVarArg=*/false);
370 DFSanNonzeroLabelFnTy = FunctionType::get(
371 Type::getVoidTy(*Ctx), ArrayRef<Type *>(), /*isVarArg=*/false);
374 Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
376 GetArgTLS = ConstantExpr::getIntToPtr(
377 ConstantInt::get(IntptrTy, uintptr_t(GetArgTLSPtr)),
378 PointerType::getUnqual(
379 FunctionType::get(PointerType::getUnqual(ArgTLSTy), (Type *)0)));
381 if (GetRetvalTLSPtr) {
383 GetRetvalTLS = ConstantExpr::getIntToPtr(
384 ConstantInt::get(IntptrTy, uintptr_t(GetRetvalTLSPtr)),
385 PointerType::getUnqual(
386 FunctionType::get(PointerType::getUnqual(ShadowTy), (Type *)0)));
389 ColdCallWeights = MDBuilder(*Ctx).createBranchWeights(1, 1000);
393 bool DataFlowSanitizer::isInstrumented(const Function *F) {
394 return !ABIList->isIn(*F, "uninstrumented");
397 bool DataFlowSanitizer::isInstrumented(const GlobalAlias *GA) {
398 return !ABIList->isIn(*GA, "uninstrumented");
401 DataFlowSanitizer::InstrumentedABI DataFlowSanitizer::getInstrumentedABI() {
402 return ClArgsABI ? IA_Args : IA_TLS;
405 DataFlowSanitizer::WrapperKind DataFlowSanitizer::getWrapperKind(Function *F) {
406 if (ABIList->isIn(*F, "functional"))
407 return WK_Functional;
408 if (ABIList->isIn(*F, "discard"))
410 if (ABIList->isIn(*F, "custom"))
416 void DataFlowSanitizer::addGlobalNamePrefix(GlobalValue *GV) {
417 std::string GVName = GV->getName(), Prefix = "dfs$";
418 GV->setName(Prefix + GVName);
420 // Try to change the name of the function in module inline asm. We only do
421 // this for specific asm directives, currently only ".symver", to try to avoid
422 // corrupting asm which happens to contain the symbol name as a substring.
423 // Note that the substitution for .symver assumes that the versioned symbol
424 // also has an instrumented name.
425 std::string Asm = GV->getParent()->getModuleInlineAsm();
426 std::string SearchStr = ".symver " + GVName + ",";
427 size_t Pos = Asm.find(SearchStr);
428 if (Pos != std::string::npos) {
429 Asm.replace(Pos, SearchStr.size(),
430 ".symver " + Prefix + GVName + "," + Prefix);
431 GV->getParent()->setModuleInlineAsm(Asm);
436 DataFlowSanitizer::buildWrapperFunction(Function *F, StringRef NewFName,
437 GlobalValue::LinkageTypes NewFLink,
438 FunctionType *NewFT) {
439 FunctionType *FT = F->getFunctionType();
440 Function *NewF = Function::Create(NewFT, NewFLink, NewFName,
442 NewF->copyAttributesFrom(F);
443 NewF->removeAttributes(
444 AttributeSet::ReturnIndex,
445 AttributeFuncs::typeIncompatible(NewFT->getReturnType(),
446 AttributeSet::ReturnIndex));
448 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", NewF);
449 std::vector<Value *> Args;
450 unsigned n = FT->getNumParams();
451 for (Function::arg_iterator ai = NewF->arg_begin(); n != 0; ++ai, --n)
452 Args.push_back(&*ai);
453 CallInst *CI = CallInst::Create(F, Args, "", BB);
454 if (FT->getReturnType()->isVoidTy())
455 ReturnInst::Create(*Ctx, BB);
457 ReturnInst::Create(*Ctx, CI, BB);
462 Constant *DataFlowSanitizer::getOrBuildTrampolineFunction(FunctionType *FT,
464 FunctionType *FTT = getTrampolineFunctionType(FT);
465 Constant *C = Mod->getOrInsertFunction(FName, FTT);
466 Function *F = dyn_cast<Function>(C);
467 if (F && F->isDeclaration()) {
468 F->setLinkage(GlobalValue::LinkOnceODRLinkage);
469 BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
470 std::vector<Value *> Args;
471 Function::arg_iterator AI = F->arg_begin(); ++AI;
472 for (unsigned N = FT->getNumParams(); N != 0; ++AI, --N)
473 Args.push_back(&*AI);
475 CallInst::Create(&F->getArgumentList().front(), Args, "", BB);
477 if (FT->getReturnType()->isVoidTy())
478 RI = ReturnInst::Create(*Ctx, BB);
480 RI = ReturnInst::Create(*Ctx, CI, BB);
482 DFSanFunction DFSF(*this, F, /*IsNativeABI=*/true);
483 Function::arg_iterator ValAI = F->arg_begin(), ShadowAI = AI; ++ValAI;
484 for (unsigned N = FT->getNumParams(); N != 0; ++ValAI, ++ShadowAI, --N)
485 DFSF.ValShadowMap[ValAI] = ShadowAI;
486 DFSanVisitor(DFSF).visitCallInst(*CI);
487 if (!FT->getReturnType()->isVoidTy())
488 new StoreInst(DFSF.getShadow(RI->getReturnValue()),
489 &F->getArgumentList().back(), RI);
495 bool DataFlowSanitizer::runOnModule(Module &M) {
499 if (ABIList->isIn(M, "skip"))
503 Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
504 ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
505 if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS))
506 G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
508 if (!GetRetvalTLSPtr) {
509 RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", ShadowTy);
510 if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS))
511 G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
514 DFSanUnionFn = Mod->getOrInsertFunction("__dfsan_union", DFSanUnionFnTy);
515 if (Function *F = dyn_cast<Function>(DFSanUnionFn)) {
516 F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
517 F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
518 F->addAttribute(1, Attribute::ZExt);
519 F->addAttribute(2, Attribute::ZExt);
522 Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
523 if (Function *F = dyn_cast<Function>(DFSanUnionLoadFn)) {
524 F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadOnly);
525 F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
527 DFSanUnimplementedFn =
528 Mod->getOrInsertFunction("__dfsan_unimplemented", DFSanUnimplementedFnTy);
530 Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy);
531 if (Function *F = dyn_cast<Function>(DFSanSetLabelFn)) {
532 F->addAttribute(1, Attribute::ZExt);
534 DFSanNonzeroLabelFn =
535 Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
537 std::vector<Function *> FnsToInstrument;
538 llvm::SmallPtrSet<Function *, 2> FnsWithNativeABI;
539 for (Module::iterator i = M.begin(), e = M.end(); i != e; ++i) {
540 if (!i->isIntrinsic() &&
542 i != DFSanUnionLoadFn &&
543 i != DFSanUnimplementedFn &&
544 i != DFSanSetLabelFn &&
545 i != DFSanNonzeroLabelFn)
546 FnsToInstrument.push_back(&*i);
549 // Give function aliases prefixes when necessary, and build wrappers where the
550 // instrumentedness is inconsistent.
551 for (Module::alias_iterator i = M.alias_begin(), e = M.alias_end(); i != e;) {
552 GlobalAlias *GA = &*i;
554 // Don't stop on weak. We assume people aren't playing games with the
555 // instrumentedness of overridden weak aliases.
556 if (Function *F = dyn_cast<Function>(
557 GA->resolveAliasedGlobal(/*stopOnWeak=*/false))) {
558 bool GAInst = isInstrumented(GA), FInst = isInstrumented(F);
559 if (GAInst && FInst) {
560 addGlobalNamePrefix(GA);
561 } else if (GAInst != FInst) {
562 // Non-instrumented alias of an instrumented function, or vice versa.
563 // Replace the alias with a native-ABI wrapper of the aliasee. The pass
564 // below will take care of instrumenting it.
566 buildWrapperFunction(F, "", GA->getLinkage(), F->getFunctionType());
567 GA->replaceAllUsesWith(NewF);
569 GA->eraseFromParent();
570 FnsToInstrument.push_back(NewF);
576 B.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
577 ReadOnlyNoneAttrs = AttributeSet::get(*Ctx, AttributeSet::FunctionIndex, B);
579 // First, change the ABI of every function in the module. ABI-listed
580 // functions keep their original ABI and get a wrapper function.
581 for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
582 e = FnsToInstrument.end();
585 FunctionType *FT = F.getFunctionType();
587 bool IsZeroArgsVoidRet = (FT->getNumParams() == 0 && !FT->isVarArg() &&
588 FT->getReturnType()->isVoidTy());
590 if (isInstrumented(&F)) {
591 // Instrumented functions get a 'dfs$' prefix. This allows us to more
592 // easily identify cases of mismatching ABIs.
593 if (getInstrumentedABI() == IA_Args && !IsZeroArgsVoidRet) {
594 FunctionType *NewFT = getArgsFunctionType(FT);
595 Function *NewF = Function::Create(NewFT, F.getLinkage(), "", &M);
596 NewF->copyAttributesFrom(&F);
597 NewF->removeAttributes(
598 AttributeSet::ReturnIndex,
599 AttributeFuncs::typeIncompatible(NewFT->getReturnType(),
600 AttributeSet::ReturnIndex));
601 for (Function::arg_iterator FArg = F.arg_begin(),
602 NewFArg = NewF->arg_begin(),
603 FArgEnd = F.arg_end();
604 FArg != FArgEnd; ++FArg, ++NewFArg) {
605 FArg->replaceAllUsesWith(NewFArg);
607 NewF->getBasicBlockList().splice(NewF->begin(), F.getBasicBlockList());
609 for (Function::use_iterator ui = F.use_begin(), ue = F.use_end();
611 BlockAddress *BA = dyn_cast<BlockAddress>(ui.getUse().getUser());
614 BA->replaceAllUsesWith(
615 BlockAddress::get(NewF, BA->getBasicBlock()));
619 F.replaceAllUsesWith(
620 ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT)));
624 addGlobalNamePrefix(NewF);
626 addGlobalNamePrefix(&F);
628 // Hopefully, nobody will try to indirectly call a vararg
630 } else if (FT->isVarArg()) {
631 UnwrappedFnMap[&F] = &F;
633 } else if (!IsZeroArgsVoidRet || getWrapperKind(&F) == WK_Custom) {
634 // Build a wrapper function for F. The wrapper simply calls F, and is
635 // added to FnsToInstrument so that any instrumentation according to its
636 // WrapperKind is done in the second pass below.
637 FunctionType *NewFT = getInstrumentedABI() == IA_Args
638 ? getArgsFunctionType(FT)
640 Function *NewF = buildWrapperFunction(
641 &F, std::string("dfsw$") + std::string(F.getName()),
642 GlobalValue::LinkOnceODRLinkage, NewFT);
643 if (getInstrumentedABI() == IA_TLS)
644 NewF->removeAttributes(AttributeSet::FunctionIndex, ReadOnlyNoneAttrs);
646 Value *WrappedFnCst =
647 ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT));
648 F.replaceAllUsesWith(WrappedFnCst);
649 UnwrappedFnMap[WrappedFnCst] = &F;
652 if (!F.isDeclaration()) {
653 // This function is probably defining an interposition of an
654 // uninstrumented function and hence needs to keep the original ABI.
655 // But any functions it may call need to use the instrumented ABI, so
656 // we instrument it in a mode which preserves the original ABI.
657 FnsWithNativeABI.insert(&F);
659 // This code needs to rebuild the iterators, as they may be invalidated
660 // by the push_back, taking care that the new range does not include
661 // any functions added by this code.
662 size_t N = i - FnsToInstrument.begin(),
663 Count = e - FnsToInstrument.begin();
664 FnsToInstrument.push_back(&F);
665 i = FnsToInstrument.begin() + N;
666 e = FnsToInstrument.begin() + Count;
671 for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
672 e = FnsToInstrument.end();
674 if (!*i || (*i)->isDeclaration())
677 removeUnreachableBlocks(**i);
679 DFSanFunction DFSF(*this, *i, FnsWithNativeABI.count(*i));
681 // DFSanVisitor may create new basic blocks, which confuses df_iterator.
682 // Build a copy of the list before iterating over it.
683 llvm::SmallVector<BasicBlock *, 4> BBList;
684 std::copy(df_begin(&(*i)->getEntryBlock()), df_end(&(*i)->getEntryBlock()),
685 std::back_inserter(BBList));
687 for (llvm::SmallVector<BasicBlock *, 4>::iterator i = BBList.begin(),
690 Instruction *Inst = &(*i)->front();
692 // DFSanVisitor may split the current basic block, changing the current
693 // instruction's next pointer and moving the next instruction to the
694 // tail block from which we should continue.
695 Instruction *Next = Inst->getNextNode();
696 // DFSanVisitor may delete Inst, so keep track of whether it was a
698 bool IsTerminator = isa<TerminatorInst>(Inst);
699 if (!DFSF.SkipInsts.count(Inst))
700 DFSanVisitor(DFSF).visit(Inst);
707 // We will not necessarily be able to compute the shadow for every phi node
708 // until we have visited every block. Therefore, the code that handles phi
709 // nodes adds them to the PHIFixups list so that they can be properly
711 for (std::vector<std::pair<PHINode *, PHINode *> >::iterator
712 i = DFSF.PHIFixups.begin(),
713 e = DFSF.PHIFixups.end();
715 for (unsigned val = 0, n = i->first->getNumIncomingValues(); val != n;
717 i->second->setIncomingValue(
718 val, DFSF.getShadow(i->first->getIncomingValue(val)));
722 // -dfsan-debug-nonzero-labels will split the CFG in all kinds of crazy
723 // places (i.e. instructions in basic blocks we haven't even begun visiting
724 // yet). To make our life easier, do this work in a pass after the main
726 if (ClDebugNonzeroLabels) {
727 for (DenseSet<Value *>::iterator i = DFSF.NonZeroChecks.begin(),
728 e = DFSF.NonZeroChecks.end();
731 if (Instruction *I = dyn_cast<Instruction>(*i))
732 Pos = I->getNextNode();
734 Pos = DFSF.F->getEntryBlock().begin();
735 while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
736 Pos = Pos->getNextNode();
737 IRBuilder<> IRB(Pos);
738 Value *Ne = IRB.CreateICmpNE(*i, DFSF.DFS.ZeroShadow);
739 BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
740 Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
741 IRBuilder<> ThenIRB(BI);
742 ThenIRB.CreateCall(DFSF.DFS.DFSanNonzeroLabelFn);
750 Value *DFSanFunction::getArgTLSPtr() {
754 return ArgTLSPtr = DFS.ArgTLS;
756 IRBuilder<> IRB(F->getEntryBlock().begin());
757 return ArgTLSPtr = IRB.CreateCall(DFS.GetArgTLS);
760 Value *DFSanFunction::getRetvalTLS() {
764 return RetvalTLSPtr = DFS.RetvalTLS;
766 IRBuilder<> IRB(F->getEntryBlock().begin());
767 return RetvalTLSPtr = IRB.CreateCall(DFS.GetRetvalTLS);
770 Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
771 IRBuilder<> IRB(Pos);
772 return IRB.CreateConstGEP2_64(getArgTLSPtr(), 0, Idx);
775 Value *DFSanFunction::getShadow(Value *V) {
776 if (!isa<Argument>(V) && !isa<Instruction>(V))
777 return DFS.ZeroShadow;
778 Value *&Shadow = ValShadowMap[V];
780 if (Argument *A = dyn_cast<Argument>(V)) {
782 return DFS.ZeroShadow;
784 case DataFlowSanitizer::IA_TLS: {
785 Value *ArgTLSPtr = getArgTLSPtr();
786 Instruction *ArgTLSPos =
787 DFS.ArgTLS ? &*F->getEntryBlock().begin()
788 : cast<Instruction>(ArgTLSPtr)->getNextNode();
789 IRBuilder<> IRB(ArgTLSPos);
790 Shadow = IRB.CreateLoad(getArgTLS(A->getArgNo(), ArgTLSPos));
793 case DataFlowSanitizer::IA_Args: {
794 unsigned ArgIdx = A->getArgNo() + F->getArgumentList().size() / 2;
795 Function::arg_iterator i = F->arg_begin();
799 assert(Shadow->getType() == DFS.ShadowTy);
803 NonZeroChecks.insert(Shadow);
805 Shadow = DFS.ZeroShadow;
811 void DFSanFunction::setShadow(Instruction *I, Value *Shadow) {
812 assert(!ValShadowMap.count(I));
813 assert(Shadow->getType() == DFS.ShadowTy);
814 ValShadowMap[I] = Shadow;
817 Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
818 assert(Addr != RetvalTLS && "Reinstrumenting?");
819 IRBuilder<> IRB(Pos);
820 return IRB.CreateIntToPtr(
822 IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy), ShadowPtrMask),
827 // Generates IR to compute the union of the two given shadows, inserting it
828 // before Pos. Returns the computed union Value.
829 Value *DataFlowSanitizer::combineShadows(Value *V1, Value *V2,
831 if (V1 == ZeroShadow)
833 if (V2 == ZeroShadow)
837 IRBuilder<> IRB(Pos);
838 BasicBlock *Head = Pos->getParent();
839 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);
861 // A convenience function which folds the shadows of each of the operands
862 // of the provided instruction Inst, inserting the IR before Inst. Returns
863 // the computed union Value.
864 Value *DFSanFunction::combineOperandShadows(Instruction *Inst) {
865 if (Inst->getNumOperands() == 0)
866 return DFS.ZeroShadow;
868 Value *Shadow = getShadow(Inst->getOperand(0));
869 for (unsigned i = 1, n = Inst->getNumOperands(); i != n; ++i) {
870 Shadow = DFS.combineShadows(Shadow, getShadow(Inst->getOperand(i)), Inst);
875 void DFSanVisitor::visitOperandShadowInst(Instruction &I) {
876 Value *CombinedShadow = DFSF.combineOperandShadows(&I);
877 DFSF.setShadow(&I, CombinedShadow);
880 // Generates IR to load shadow corresponding to bytes [Addr, Addr+Size), where
881 // Addr has alignment Align, and take the union of each of those shadows.
882 Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
884 if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
885 llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
886 AllocaShadowMap.find(AI);
887 if (i != AllocaShadowMap.end()) {
888 IRBuilder<> IRB(Pos);
889 return IRB.CreateLoad(i->second);
893 uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
894 SmallVector<Value *, 2> Objs;
895 GetUnderlyingObjects(Addr, Objs, DFS.DL);
896 bool AllConstants = true;
897 for (SmallVector<Value *, 2>::iterator i = Objs.begin(), e = Objs.end();
899 if (isa<Function>(*i) || isa<BlockAddress>(*i))
901 if (isa<GlobalVariable>(*i) && cast<GlobalVariable>(*i)->isConstant())
904 AllConstants = false;
908 return DFS.ZeroShadow;
910 Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
913 return DFS.ZeroShadow;
915 LoadInst *LI = new LoadInst(ShadowAddr, "", Pos);
916 LI->setAlignment(ShadowAlign);
920 IRBuilder<> IRB(Pos);
922 IRB.CreateGEP(ShadowAddr, ConstantInt::get(DFS.IntptrTy, 1));
923 return DFS.combineShadows(IRB.CreateAlignedLoad(ShadowAddr, ShadowAlign),
924 IRB.CreateAlignedLoad(ShadowAddr1, ShadowAlign),
928 if (Size % (64 / DFS.ShadowWidth) == 0) {
929 // Fast path for the common case where each byte has identical shadow: load
930 // shadow 64 bits at a time, fall out to a __dfsan_union_load call if any
931 // shadow is non-equal.
932 BasicBlock *FallbackBB = BasicBlock::Create(*DFS.Ctx, "", F);
933 IRBuilder<> FallbackIRB(FallbackBB);
934 CallInst *FallbackCall = FallbackIRB.CreateCall2(
935 DFS.DFSanUnionLoadFn, ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size));
936 FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
938 // Compare each of the shadows stored in the loaded 64 bits to each other,
939 // by computing (WideShadow rotl ShadowWidth) == WideShadow.
940 IRBuilder<> IRB(Pos);
942 IRB.CreateBitCast(ShadowAddr, Type::getInt64PtrTy(*DFS.Ctx));
943 Value *WideShadow = IRB.CreateAlignedLoad(WideAddr, ShadowAlign);
944 Value *TruncShadow = IRB.CreateTrunc(WideShadow, DFS.ShadowTy);
945 Value *ShlShadow = IRB.CreateShl(WideShadow, DFS.ShadowWidth);
946 Value *ShrShadow = IRB.CreateLShr(WideShadow, 64 - DFS.ShadowWidth);
947 Value *RotShadow = IRB.CreateOr(ShlShadow, ShrShadow);
948 Value *ShadowsEq = IRB.CreateICmpEQ(WideShadow, RotShadow);
950 BasicBlock *Head = Pos->getParent();
951 BasicBlock *Tail = Head->splitBasicBlock(Pos);
952 // In the following code LastBr will refer to the previous basic block's
953 // conditional branch instruction, whose true successor is fixed up to point
954 // to the next block during the loop below or to the tail after the final
956 BranchInst *LastBr = BranchInst::Create(FallbackBB, FallbackBB, ShadowsEq);
957 ReplaceInstWithInst(Head->getTerminator(), LastBr);
959 for (uint64_t Ofs = 64 / DFS.ShadowWidth; Ofs != Size;
960 Ofs += 64 / DFS.ShadowWidth) {
961 BasicBlock *NextBB = BasicBlock::Create(*DFS.Ctx, "", F);
962 IRBuilder<> NextIRB(NextBB);
963 WideAddr = NextIRB.CreateGEP(WideAddr, ConstantInt::get(DFS.IntptrTy, 1));
964 Value *NextWideShadow = NextIRB.CreateAlignedLoad(WideAddr, ShadowAlign);
965 ShadowsEq = NextIRB.CreateICmpEQ(WideShadow, NextWideShadow);
966 LastBr->setSuccessor(0, NextBB);
967 LastBr = NextIRB.CreateCondBr(ShadowsEq, FallbackBB, FallbackBB);
970 LastBr->setSuccessor(0, Tail);
971 FallbackIRB.CreateBr(Tail);
972 PHINode *Shadow = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
973 Shadow->addIncoming(FallbackCall, FallbackBB);
974 Shadow->addIncoming(TruncShadow, LastBr->getParent());
978 IRBuilder<> IRB(Pos);
979 CallInst *FallbackCall = IRB.CreateCall2(
980 DFS.DFSanUnionLoadFn, ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size));
981 FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
985 void DFSanVisitor::visitLoadInst(LoadInst &LI) {
986 uint64_t Size = DFSF.DFS.DL->getTypeStoreSize(LI.getType());
988 if (ClPreserveAlignment) {
989 Align = LI.getAlignment();
991 Align = DFSF.DFS.DL->getABITypeAlignment(LI.getType());
995 IRBuilder<> IRB(&LI);
996 Value *Shadow = DFSF.loadShadow(LI.getPointerOperand(), Size, Align, &LI);
997 if (ClCombinePointerLabelsOnLoad) {
998 Value *PtrShadow = DFSF.getShadow(LI.getPointerOperand());
999 Shadow = DFSF.DFS.combineShadows(Shadow, PtrShadow, &LI);
1001 if (Shadow != DFSF.DFS.ZeroShadow)
1002 DFSF.NonZeroChecks.insert(Shadow);
1004 DFSF.setShadow(&LI, Shadow);
1007 void DFSanFunction::storeShadow(Value *Addr, uint64_t Size, uint64_t Align,
1008 Value *Shadow, Instruction *Pos) {
1009 if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
1010 llvm::DenseMap<AllocaInst *, AllocaInst *>::iterator i =
1011 AllocaShadowMap.find(AI);
1012 if (i != AllocaShadowMap.end()) {
1013 IRBuilder<> IRB(Pos);
1014 IRB.CreateStore(Shadow, i->second);
1019 uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
1020 IRBuilder<> IRB(Pos);
1021 Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
1022 if (Shadow == DFS.ZeroShadow) {
1023 IntegerType *ShadowTy = IntegerType::get(*DFS.Ctx, Size * DFS.ShadowWidth);
1024 Value *ExtZeroShadow = ConstantInt::get(ShadowTy, 0);
1025 Value *ExtShadowAddr =
1026 IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowTy));
1027 IRB.CreateAlignedStore(ExtZeroShadow, ExtShadowAddr, ShadowAlign);
1031 const unsigned ShadowVecSize = 128 / DFS.ShadowWidth;
1032 uint64_t Offset = 0;
1033 if (Size >= ShadowVecSize) {
1034 VectorType *ShadowVecTy = VectorType::get(DFS.ShadowTy, ShadowVecSize);
1035 Value *ShadowVec = UndefValue::get(ShadowVecTy);
1036 for (unsigned i = 0; i != ShadowVecSize; ++i) {
1037 ShadowVec = IRB.CreateInsertElement(
1038 ShadowVec, Shadow, ConstantInt::get(Type::getInt32Ty(*DFS.Ctx), i));
1040 Value *ShadowVecAddr =
1041 IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowVecTy));
1043 Value *CurShadowVecAddr = IRB.CreateConstGEP1_32(ShadowVecAddr, Offset);
1044 IRB.CreateAlignedStore(ShadowVec, CurShadowVecAddr, ShadowAlign);
1045 Size -= ShadowVecSize;
1047 } while (Size >= ShadowVecSize);
1048 Offset *= ShadowVecSize;
1051 Value *CurShadowAddr = IRB.CreateConstGEP1_32(ShadowAddr, Offset);
1052 IRB.CreateAlignedStore(Shadow, CurShadowAddr, ShadowAlign);
1058 void DFSanVisitor::visitStoreInst(StoreInst &SI) {
1060 DFSF.DFS.DL->getTypeStoreSize(SI.getValueOperand()->getType());
1062 if (ClPreserveAlignment) {
1063 Align = SI.getAlignment();
1065 Align = DFSF.DFS.DL->getABITypeAlignment(SI.getValueOperand()->getType());
1070 Value* Shadow = DFSF.getShadow(SI.getValueOperand());
1071 if (ClCombinePointerLabelsOnStore) {
1072 Value *PtrShadow = DFSF.getShadow(SI.getPointerOperand());
1073 Shadow = DFSF.DFS.combineShadows(Shadow, PtrShadow, &SI);
1075 DFSF.storeShadow(SI.getPointerOperand(), Size, Align, Shadow, &SI);
1078 void DFSanVisitor::visitBinaryOperator(BinaryOperator &BO) {
1079 visitOperandShadowInst(BO);
1082 void DFSanVisitor::visitCastInst(CastInst &CI) { visitOperandShadowInst(CI); }
1084 void DFSanVisitor::visitCmpInst(CmpInst &CI) { visitOperandShadowInst(CI); }
1086 void DFSanVisitor::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
1087 visitOperandShadowInst(GEPI);
1090 void DFSanVisitor::visitExtractElementInst(ExtractElementInst &I) {
1091 visitOperandShadowInst(I);
1094 void DFSanVisitor::visitInsertElementInst(InsertElementInst &I) {
1095 visitOperandShadowInst(I);
1098 void DFSanVisitor::visitShuffleVectorInst(ShuffleVectorInst &I) {
1099 visitOperandShadowInst(I);
1102 void DFSanVisitor::visitExtractValueInst(ExtractValueInst &I) {
1103 visitOperandShadowInst(I);
1106 void DFSanVisitor::visitInsertValueInst(InsertValueInst &I) {
1107 visitOperandShadowInst(I);
1110 void DFSanVisitor::visitAllocaInst(AllocaInst &I) {
1111 bool AllLoadsStores = true;
1112 for (Instruction::use_iterator i = I.use_begin(), e = I.use_end(); i != e;
1114 if (isa<LoadInst>(*i))
1117 if (StoreInst *SI = dyn_cast<StoreInst>(*i)) {
1118 if (SI->getPointerOperand() == &I)
1122 AllLoadsStores = false;
1125 if (AllLoadsStores) {
1126 IRBuilder<> IRB(&I);
1127 DFSF.AllocaShadowMap[&I] = IRB.CreateAlloca(DFSF.DFS.ShadowTy);
1129 DFSF.setShadow(&I, DFSF.DFS.ZeroShadow);
1132 void DFSanVisitor::visitSelectInst(SelectInst &I) {
1133 Value *CondShadow = DFSF.getShadow(I.getCondition());
1134 Value *TrueShadow = DFSF.getShadow(I.getTrueValue());
1135 Value *FalseShadow = DFSF.getShadow(I.getFalseValue());
1137 if (isa<VectorType>(I.getCondition()->getType())) {
1139 &I, DFSF.DFS.combineShadows(
1141 DFSF.DFS.combineShadows(TrueShadow, FalseShadow, &I), &I));
1144 if (TrueShadow == FalseShadow) {
1145 ShadowSel = TrueShadow;
1148 SelectInst::Create(I.getCondition(), TrueShadow, FalseShadow, "", &I);
1150 DFSF.setShadow(&I, DFSF.DFS.combineShadows(CondShadow, ShadowSel, &I));
1154 void DFSanVisitor::visitMemSetInst(MemSetInst &I) {
1155 IRBuilder<> IRB(&I);
1156 Value *ValShadow = DFSF.getShadow(I.getValue());
1158 DFSF.DFS.DFSanSetLabelFn, ValShadow,
1159 IRB.CreateBitCast(I.getDest(), Type::getInt8PtrTy(*DFSF.DFS.Ctx)),
1160 IRB.CreateZExtOrTrunc(I.getLength(), DFSF.DFS.IntptrTy));
1163 void DFSanVisitor::visitMemTransferInst(MemTransferInst &I) {
1164 IRBuilder<> IRB(&I);
1165 Value *DestShadow = DFSF.DFS.getShadowAddress(I.getDest(), &I);
1166 Value *SrcShadow = DFSF.DFS.getShadowAddress(I.getSource(), &I);
1167 Value *LenShadow = IRB.CreateMul(
1169 ConstantInt::get(I.getLength()->getType(), DFSF.DFS.ShadowWidth / 8));
1171 if (ClPreserveAlignment) {
1172 AlignShadow = IRB.CreateMul(I.getAlignmentCst(),
1173 ConstantInt::get(I.getAlignmentCst()->getType(),
1174 DFSF.DFS.ShadowWidth / 8));
1176 AlignShadow = ConstantInt::get(I.getAlignmentCst()->getType(),
1177 DFSF.DFS.ShadowWidth / 8);
1179 Type *Int8Ptr = Type::getInt8PtrTy(*DFSF.DFS.Ctx);
1180 DestShadow = IRB.CreateBitCast(DestShadow, Int8Ptr);
1181 SrcShadow = IRB.CreateBitCast(SrcShadow, Int8Ptr);
1182 IRB.CreateCall5(I.getCalledValue(), DestShadow, SrcShadow, LenShadow,
1183 AlignShadow, I.getVolatileCst());
1186 void DFSanVisitor::visitReturnInst(ReturnInst &RI) {
1187 if (!DFSF.IsNativeABI && RI.getReturnValue()) {
1189 case DataFlowSanitizer::IA_TLS: {
1190 Value *S = DFSF.getShadow(RI.getReturnValue());
1191 IRBuilder<> IRB(&RI);
1192 IRB.CreateStore(S, DFSF.getRetvalTLS());
1195 case DataFlowSanitizer::IA_Args: {
1196 IRBuilder<> IRB(&RI);
1197 Type *RT = DFSF.F->getFunctionType()->getReturnType();
1199 IRB.CreateInsertValue(UndefValue::get(RT), RI.getReturnValue(), 0);
1201 IRB.CreateInsertValue(InsVal, DFSF.getShadow(RI.getReturnValue()), 1);
1202 RI.setOperand(0, InsShadow);
1209 void DFSanVisitor::visitCallSite(CallSite CS) {
1210 Function *F = CS.getCalledFunction();
1211 if ((F && F->isIntrinsic()) || isa<InlineAsm>(CS.getCalledValue())) {
1212 visitOperandShadowInst(*CS.getInstruction());
1216 IRBuilder<> IRB(CS.getInstruction());
1218 DenseMap<Value *, Function *>::iterator i =
1219 DFSF.DFS.UnwrappedFnMap.find(CS.getCalledValue());
1220 if (i != DFSF.DFS.UnwrappedFnMap.end()) {
1221 Function *F = i->second;
1222 switch (DFSF.DFS.getWrapperKind(F)) {
1223 case DataFlowSanitizer::WK_Warning: {
1224 CS.setCalledFunction(F);
1225 IRB.CreateCall(DFSF.DFS.DFSanUnimplementedFn,
1226 IRB.CreateGlobalStringPtr(F->getName()));
1227 DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1230 case DataFlowSanitizer::WK_Discard: {
1231 CS.setCalledFunction(F);
1232 DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1235 case DataFlowSanitizer::WK_Functional: {
1236 CS.setCalledFunction(F);
1237 visitOperandShadowInst(*CS.getInstruction());
1240 case DataFlowSanitizer::WK_Custom: {
1241 // Don't try to handle invokes of custom functions, it's too complicated.
1242 // Instead, invoke the dfsw$ wrapper, which will in turn call the __dfsw_
1244 if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) {
1245 FunctionType *FT = F->getFunctionType();
1246 FunctionType *CustomFT = DFSF.DFS.getCustomFunctionType(FT);
1247 std::string CustomFName = "__dfsw_";
1248 CustomFName += F->getName();
1250 DFSF.DFS.Mod->getOrInsertFunction(CustomFName, CustomFT);
1251 if (Function *CustomFn = dyn_cast<Function>(CustomF)) {
1252 CustomFn->copyAttributesFrom(F);
1254 // Custom functions returning non-void will write to the return label.
1255 if (!FT->getReturnType()->isVoidTy()) {
1256 CustomFn->removeAttributes(AttributeSet::FunctionIndex,
1257 DFSF.DFS.ReadOnlyNoneAttrs);
1261 std::vector<Value *> Args;
1263 CallSite::arg_iterator i = CS.arg_begin();
1264 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n) {
1265 Type *T = (*i)->getType();
1266 FunctionType *ParamFT;
1267 if (isa<PointerType>(T) &&
1268 (ParamFT = dyn_cast<FunctionType>(
1269 cast<PointerType>(T)->getElementType()))) {
1270 std::string TName = "dfst";
1271 TName += utostr(FT->getNumParams() - n);
1273 TName += F->getName();
1274 Constant *T = DFSF.DFS.getOrBuildTrampolineFunction(ParamFT, TName);
1277 IRB.CreateBitCast(*i, Type::getInt8PtrTy(*DFSF.DFS.Ctx)));
1284 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1285 Args.push_back(DFSF.getShadow(*i));
1287 if (!FT->getReturnType()->isVoidTy()) {
1288 if (!DFSF.LabelReturnAlloca) {
1289 DFSF.LabelReturnAlloca =
1290 new AllocaInst(DFSF.DFS.ShadowTy, "labelreturn",
1291 DFSF.F->getEntryBlock().begin());
1293 Args.push_back(DFSF.LabelReturnAlloca);
1296 CallInst *CustomCI = IRB.CreateCall(CustomF, Args);
1297 CustomCI->setCallingConv(CI->getCallingConv());
1298 CustomCI->setAttributes(CI->getAttributes());
1300 if (!FT->getReturnType()->isVoidTy()) {
1301 LoadInst *LabelLoad = IRB.CreateLoad(DFSF.LabelReturnAlloca);
1302 DFSF.setShadow(CustomCI, LabelLoad);
1305 CI->replaceAllUsesWith(CustomCI);
1306 CI->eraseFromParent();
1314 FunctionType *FT = cast<FunctionType>(
1315 CS.getCalledValue()->getType()->getPointerElementType());
1316 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1317 for (unsigned i = 0, n = FT->getNumParams(); i != n; ++i) {
1318 IRB.CreateStore(DFSF.getShadow(CS.getArgument(i)),
1319 DFSF.getArgTLS(i, CS.getInstruction()));
1323 Instruction *Next = 0;
1324 if (!CS.getType()->isVoidTy()) {
1325 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1326 if (II->getNormalDest()->getSinglePredecessor()) {
1327 Next = II->getNormalDest()->begin();
1330 SplitEdge(II->getParent(), II->getNormalDest(), &DFSF.DFS);
1331 Next = NewBB->begin();
1334 Next = CS->getNextNode();
1337 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1338 IRBuilder<> NextIRB(Next);
1339 LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
1340 DFSF.SkipInsts.insert(LI);
1341 DFSF.setShadow(CS.getInstruction(), LI);
1342 DFSF.NonZeroChecks.insert(LI);
1346 // Do all instrumentation for IA_Args down here to defer tampering with the
1347 // CFG in a way that SplitEdge may be able to detect.
1348 if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_Args) {
1349 FunctionType *NewFT = DFSF.DFS.getArgsFunctionType(FT);
1351 IRB.CreateBitCast(CS.getCalledValue(), PointerType::getUnqual(NewFT));
1352 std::vector<Value *> Args;
1354 CallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
1355 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1359 for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1360 Args.push_back(DFSF.getShadow(*i));
1362 if (FT->isVarArg()) {
1363 unsigned VarArgSize = CS.arg_size() - FT->getNumParams();
1364 ArrayType *VarArgArrayTy = ArrayType::get(DFSF.DFS.ShadowTy, VarArgSize);
1365 AllocaInst *VarArgShadow =
1366 new AllocaInst(VarArgArrayTy, "", DFSF.F->getEntryBlock().begin());
1367 Args.push_back(IRB.CreateConstGEP2_32(VarArgShadow, 0, 0));
1368 for (unsigned n = 0; i != e; ++i, ++n) {
1369 IRB.CreateStore(DFSF.getShadow(*i),
1370 IRB.CreateConstGEP2_32(VarArgShadow, 0, n));
1376 if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1377 NewCS = IRB.CreateInvoke(Func, II->getNormalDest(), II->getUnwindDest(),
1380 NewCS = IRB.CreateCall(Func, Args);
1382 NewCS.setCallingConv(CS.getCallingConv());
1383 NewCS.setAttributes(CS.getAttributes().removeAttributes(
1384 *DFSF.DFS.Ctx, AttributeSet::ReturnIndex,
1385 AttributeFuncs::typeIncompatible(NewCS.getInstruction()->getType(),
1386 AttributeSet::ReturnIndex)));
1389 ExtractValueInst *ExVal =
1390 ExtractValueInst::Create(NewCS.getInstruction(), 0, "", Next);
1391 DFSF.SkipInsts.insert(ExVal);
1392 ExtractValueInst *ExShadow =
1393 ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
1394 DFSF.SkipInsts.insert(ExShadow);
1395 DFSF.setShadow(ExVal, ExShadow);
1396 DFSF.NonZeroChecks.insert(ExShadow);
1398 CS.getInstruction()->replaceAllUsesWith(ExVal);
1401 CS.getInstruction()->eraseFromParent();
1405 void DFSanVisitor::visitPHINode(PHINode &PN) {
1407 PHINode::Create(DFSF.DFS.ShadowTy, PN.getNumIncomingValues(), "", &PN);
1409 // Give the shadow phi node valid predecessors to fool SplitEdge into working.
1410 Value *UndefShadow = UndefValue::get(DFSF.DFS.ShadowTy);
1411 for (PHINode::block_iterator i = PN.block_begin(), e = PN.block_end(); i != e;
1413 ShadowPN->addIncoming(UndefShadow, *i);
1416 DFSF.PHIFixups.push_back(std::make_pair(&PN, ShadowPN));
1417 DFSF.setShadow(&PN, ShadowPN);