LLVM  3.7.0
DataFlowSanitizer.cpp
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1 //===-- DataFlowSanitizer.cpp - dynamic data flow analysis ----------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 /// \file
10 /// This file is a part of DataFlowSanitizer, a generalised dynamic data flow
11 /// analysis.
12 ///
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.
17 ///
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:
22 ///
23 /// +--------------------+ 0x800000000000 (top of memory)
24 /// | application memory |
25 /// +--------------------+ 0x700000008000 (kAppAddr)
26 /// | |
27 /// | unused |
28 /// | |
29 /// +--------------------+ 0x200200000000 (kUnusedAddr)
30 /// | union table |
31 /// +--------------------+ 0x200000000000 (kUnionTableAddr)
32 /// | shadow memory |
33 /// +--------------------+ 0x000000010000 (kShadowAddr)
34 /// | reserved by kernel |
35 /// +--------------------+ 0x000000000000
36 ///
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.
43 ///
44 /// For more information, please refer to the design document:
45 /// http://clang.llvm.org/docs/DataFlowSanitizerDesign.html
46 
48 #include "llvm/ADT/DenseMap.h"
49 #include "llvm/ADT/DenseSet.h"
51 #include "llvm/ADT/StringExtras.h"
52 #include "llvm/ADT/Triple.h"
54 #include "llvm/IR/Dominators.h"
55 #include "llvm/IR/DebugInfo.h"
56 #include "llvm/IR/IRBuilder.h"
57 #include "llvm/IR/InlineAsm.h"
58 #include "llvm/IR/InstVisitor.h"
59 #include "llvm/IR/LLVMContext.h"
60 #include "llvm/IR/MDBuilder.h"
61 #include "llvm/IR/Type.h"
62 #include "llvm/IR/Value.h"
63 #include "llvm/Pass.h"
68 #include <algorithm>
69 #include <iterator>
70 #include <set>
71 #include <utility>
72 
73 using namespace llvm;
74 
75 // The -dfsan-preserve-alignment flag controls whether this pass assumes that
76 // alignment requirements provided by the input IR are correct. For example,
77 // if the input IR contains a load with alignment 8, this flag will cause
78 // the shadow load to have alignment 16. This flag is disabled by default as
79 // we have unfortunately encountered too much code (including Clang itself;
80 // see PR14291) which performs misaligned access.
82  "dfsan-preserve-alignment",
83  cl::desc("respect alignment requirements provided by input IR"), cl::Hidden,
84  cl::init(false));
85 
86 // The ABI list files control how shadow parameters are passed. The pass treats
87 // every function labelled "uninstrumented" in the ABI list file as conforming
88 // to the "native" (i.e. unsanitized) ABI. Unless the ABI list contains
89 // additional annotations for those functions, a call to one of those functions
90 // will produce a warning message, as the labelling behaviour of the function is
91 // unknown. The other supported annotations are "functional" and "discard",
92 // which are described below under DataFlowSanitizer::WrapperKind.
94  "dfsan-abilist",
95  cl::desc("File listing native ABI functions and how the pass treats them"),
96  cl::Hidden);
97 
98 // Controls whether the pass uses IA_Args or IA_TLS as the ABI for instrumented
99 // functions (see DataFlowSanitizer::InstrumentedABI below).
100 static cl::opt<bool> ClArgsABI(
101  "dfsan-args-abi",
102  cl::desc("Use the argument ABI rather than the TLS ABI"),
103  cl::Hidden);
104 
105 // Controls whether the pass includes or ignores the labels of pointers in load
106 // instructions.
108  "dfsan-combine-pointer-labels-on-load",
109  cl::desc("Combine the label of the pointer with the label of the data when "
110  "loading from memory."),
111  cl::Hidden, cl::init(true));
112 
113 // Controls whether the pass includes or ignores the labels of pointers in
114 // stores instructions.
116  "dfsan-combine-pointer-labels-on-store",
117  cl::desc("Combine the label of the pointer with the label of the data when "
118  "storing in memory."),
119  cl::Hidden, cl::init(false));
120 
122  "dfsan-debug-nonzero-labels",
123  cl::desc("Insert calls to __dfsan_nonzero_label on observing a parameter, "
124  "load or return with a nonzero label"),
125  cl::Hidden);
126 
127 namespace {
128 
129 StringRef GetGlobalTypeString(const GlobalValue &G) {
130  // Types of GlobalVariables are always pointer types.
131  Type *GType = G.getType()->getElementType();
132  // For now we support blacklisting struct types only.
133  if (StructType *SGType = dyn_cast<StructType>(GType)) {
134  if (!SGType->isLiteral())
135  return SGType->getName();
136  }
137  return "<unknown type>";
138 }
139 
140 class DFSanABIList {
141  std::unique_ptr<SpecialCaseList> SCL;
142 
143  public:
144  DFSanABIList() {}
145 
146  void set(std::unique_ptr<SpecialCaseList> List) { SCL = std::move(List); }
147 
148  /// Returns whether either this function or its source file are listed in the
149  /// given category.
150  bool isIn(const Function &F, StringRef Category) const {
151  return isIn(*F.getParent(), Category) ||
152  SCL->inSection("fun", F.getName(), Category);
153  }
154 
155  /// Returns whether this global alias is listed in the given category.
156  ///
157  /// If GA aliases a function, the alias's name is matched as a function name
158  /// would be. Similarly, aliases of globals are matched like globals.
159  bool isIn(const GlobalAlias &GA, StringRef Category) const {
160  if (isIn(*GA.getParent(), Category))
161  return true;
162 
163  if (isa<FunctionType>(GA.getType()->getElementType()))
164  return SCL->inSection("fun", GA.getName(), Category);
165 
166  return SCL->inSection("global", GA.getName(), Category) ||
167  SCL->inSection("type", GetGlobalTypeString(GA), Category);
168  }
169 
170  /// Returns whether this module is listed in the given category.
171  bool isIn(const Module &M, StringRef Category) const {
172  return SCL->inSection("src", M.getModuleIdentifier(), Category);
173  }
174 };
175 
176 class DataFlowSanitizer : public ModulePass {
177  friend struct DFSanFunction;
178  friend class DFSanVisitor;
179 
180  enum {
181  ShadowWidth = 16
182  };
183 
184  /// Which ABI should be used for instrumented functions?
185  enum InstrumentedABI {
186  /// Argument and return value labels are passed through additional
187  /// arguments and by modifying the return type.
188  IA_Args,
189 
190  /// Argument and return value labels are passed through TLS variables
191  /// __dfsan_arg_tls and __dfsan_retval_tls.
192  IA_TLS
193  };
194 
195  /// How should calls to uninstrumented functions be handled?
196  enum WrapperKind {
197  /// This function is present in an uninstrumented form but we don't know
198  /// how it should be handled. Print a warning and call the function anyway.
199  /// Don't label the return value.
200  WK_Warning,
201 
202  /// This function does not write to (user-accessible) memory, and its return
203  /// value is unlabelled.
204  WK_Discard,
205 
206  /// This function does not write to (user-accessible) memory, and the label
207  /// of its return value is the union of the label of its arguments.
208  WK_Functional,
209 
210  /// Instead of calling the function, a custom wrapper __dfsw_F is called,
211  /// where F is the name of the function. This function may wrap the
212  /// original function or provide its own implementation. This is similar to
213  /// the IA_Args ABI, except that IA_Args uses a struct return type to
214  /// pass the return value shadow in a register, while WK_Custom uses an
215  /// extra pointer argument to return the shadow. This allows the wrapped
216  /// form of the function type to be expressed in C.
217  WK_Custom
218  };
219 
220  Module *Mod;
221  LLVMContext *Ctx;
222  IntegerType *ShadowTy;
223  PointerType *ShadowPtrTy;
224  IntegerType *IntptrTy;
225  ConstantInt *ZeroShadow;
226  ConstantInt *ShadowPtrMask;
227  ConstantInt *ShadowPtrMul;
228  Constant *ArgTLS;
229  Constant *RetvalTLS;
230  void *(*GetArgTLSPtr)();
231  void *(*GetRetvalTLSPtr)();
232  Constant *GetArgTLS;
233  Constant *GetRetvalTLS;
234  FunctionType *DFSanUnionFnTy;
235  FunctionType *DFSanUnionLoadFnTy;
236  FunctionType *DFSanUnimplementedFnTy;
237  FunctionType *DFSanSetLabelFnTy;
238  FunctionType *DFSanNonzeroLabelFnTy;
239  FunctionType *DFSanVarargWrapperFnTy;
240  Constant *DFSanUnionFn;
241  Constant *DFSanCheckedUnionFn;
242  Constant *DFSanUnionLoadFn;
243  Constant *DFSanUnimplementedFn;
244  Constant *DFSanSetLabelFn;
245  Constant *DFSanNonzeroLabelFn;
246  Constant *DFSanVarargWrapperFn;
247  MDNode *ColdCallWeights;
248  DFSanABIList ABIList;
249  DenseMap<Value *, Function *> UnwrappedFnMap;
250  AttributeSet ReadOnlyNoneAttrs;
252 
253  Value *getShadowAddress(Value *Addr, Instruction *Pos);
254  bool isInstrumented(const Function *F);
255  bool isInstrumented(const GlobalAlias *GA);
256  FunctionType *getArgsFunctionType(FunctionType *T);
257  FunctionType *getTrampolineFunctionType(FunctionType *T);
258  FunctionType *getCustomFunctionType(FunctionType *T);
259  InstrumentedABI getInstrumentedABI();
260  WrapperKind getWrapperKind(Function *F);
261  void addGlobalNamePrefix(GlobalValue *GV);
262  Function *buildWrapperFunction(Function *F, StringRef NewFName,
263  GlobalValue::LinkageTypes NewFLink,
264  FunctionType *NewFT);
265  Constant *getOrBuildTrampolineFunction(FunctionType *FT, StringRef FName);
266 
267  public:
268  DataFlowSanitizer(
269  const std::vector<std::string> &ABIListFiles = std::vector<std::string>(),
270  void *(*getArgTLS)() = nullptr, void *(*getRetValTLS)() = nullptr);
271  static char ID;
272  bool doInitialization(Module &M) override;
273  bool runOnModule(Module &M) override;
274 };
275 
276 struct DFSanFunction {
277  DataFlowSanitizer &DFS;
278  Function *F;
279  DominatorTree DT;
280  DataFlowSanitizer::InstrumentedABI IA;
281  bool IsNativeABI;
282  Value *ArgTLSPtr;
283  Value *RetvalTLSPtr;
284  AllocaInst *LabelReturnAlloca;
285  DenseMap<Value *, Value *> ValShadowMap;
286  DenseMap<AllocaInst *, AllocaInst *> AllocaShadowMap;
287  std::vector<std::pair<PHINode *, PHINode *> > PHIFixups;
288  DenseSet<Instruction *> SkipInsts;
289  std::vector<Value *> NonZeroChecks;
290  bool AvoidNewBlocks;
291 
292  struct CachedCombinedShadow {
293  BasicBlock *Block;
294  Value *Shadow;
295  };
296  DenseMap<std::pair<Value *, Value *>, CachedCombinedShadow>
297  CachedCombinedShadows;
298  DenseMap<Value *, std::set<Value *>> ShadowElements;
299 
300  DFSanFunction(DataFlowSanitizer &DFS, Function *F, bool IsNativeABI)
301  : DFS(DFS), F(F), IA(DFS.getInstrumentedABI()),
302  IsNativeABI(IsNativeABI), ArgTLSPtr(nullptr), RetvalTLSPtr(nullptr),
303  LabelReturnAlloca(nullptr) {
304  DT.recalculate(*F);
305  // FIXME: Need to track down the register allocator issue which causes poor
306  // performance in pathological cases with large numbers of basic blocks.
307  AvoidNewBlocks = F->size() > 1000;
308  }
309  Value *getArgTLSPtr();
310  Value *getArgTLS(unsigned Index, Instruction *Pos);
311  Value *getRetvalTLS();
312  Value *getShadow(Value *V);
313  void setShadow(Instruction *I, Value *Shadow);
314  Value *combineShadows(Value *V1, Value *V2, Instruction *Pos);
315  Value *combineOperandShadows(Instruction *Inst);
316  Value *loadShadow(Value *ShadowAddr, uint64_t Size, uint64_t Align,
317  Instruction *Pos);
318  void storeShadow(Value *Addr, uint64_t Size, uint64_t Align, Value *Shadow,
319  Instruction *Pos);
320 };
321 
322 class DFSanVisitor : public InstVisitor<DFSanVisitor> {
323  public:
324  DFSanFunction &DFSF;
325  DFSanVisitor(DFSanFunction &DFSF) : DFSF(DFSF) {}
326 
327  void visitOperandShadowInst(Instruction &I);
328 
329  void visitBinaryOperator(BinaryOperator &BO);
330  void visitCastInst(CastInst &CI);
331  void visitCmpInst(CmpInst &CI);
332  void visitGetElementPtrInst(GetElementPtrInst &GEPI);
333  void visitLoadInst(LoadInst &LI);
334  void visitStoreInst(StoreInst &SI);
335  void visitReturnInst(ReturnInst &RI);
336  void visitCallSite(CallSite CS);
337  void visitPHINode(PHINode &PN);
338  void visitExtractElementInst(ExtractElementInst &I);
339  void visitInsertElementInst(InsertElementInst &I);
340  void visitShuffleVectorInst(ShuffleVectorInst &I);
341  void visitExtractValueInst(ExtractValueInst &I);
342  void visitInsertValueInst(InsertValueInst &I);
343  void visitAllocaInst(AllocaInst &I);
344  void visitSelectInst(SelectInst &I);
345  void visitMemSetInst(MemSetInst &I);
346  void visitMemTransferInst(MemTransferInst &I);
347 };
348 
349 }
350 
352 INITIALIZE_PASS(DataFlowSanitizer, "dfsan",
353  "DataFlowSanitizer: dynamic data flow analysis.", false, false)
354 
355 ModulePass *
356 llvm::createDataFlowSanitizerPass(const std::vector<std::string> &ABIListFiles,
357  void *(*getArgTLS)(),
358  void *(*getRetValTLS)()) {
359  return new DataFlowSanitizer(ABIListFiles, getArgTLS, getRetValTLS);
360 }
361 
362 DataFlowSanitizer::DataFlowSanitizer(
363  const std::vector<std::string> &ABIListFiles, void *(*getArgTLS)(),
364  void *(*getRetValTLS)())
365  : ModulePass(ID), GetArgTLSPtr(getArgTLS), GetRetvalTLSPtr(getRetValTLS) {
366  std::vector<std::string> AllABIListFiles(std::move(ABIListFiles));
367  AllABIListFiles.insert(AllABIListFiles.end(), ClABIListFiles.begin(),
368  ClABIListFiles.end());
369  ABIList.set(SpecialCaseList::createOrDie(AllABIListFiles));
370 }
371 
372 FunctionType *DataFlowSanitizer::getArgsFunctionType(FunctionType *T) {
374  ArgTypes.append(T->getNumParams(), ShadowTy);
375  if (T->isVarArg())
376  ArgTypes.push_back(ShadowPtrTy);
377  Type *RetType = T->getReturnType();
378  if (!RetType->isVoidTy())
379  RetType = StructType::get(RetType, ShadowTy, (Type *)nullptr);
380  return FunctionType::get(RetType, ArgTypes, T->isVarArg());
381 }
382 
383 FunctionType *DataFlowSanitizer::getTrampolineFunctionType(FunctionType *T) {
384  assert(!T->isVarArg());
386  ArgTypes.push_back(T->getPointerTo());
387  ArgTypes.append(T->param_begin(), T->param_end());
388  ArgTypes.append(T->getNumParams(), ShadowTy);
389  Type *RetType = T->getReturnType();
390  if (!RetType->isVoidTy())
391  ArgTypes.push_back(ShadowPtrTy);
392  return FunctionType::get(T->getReturnType(), ArgTypes, false);
393 }
394 
395 FunctionType *DataFlowSanitizer::getCustomFunctionType(FunctionType *T) {
397  for (FunctionType::param_iterator i = T->param_begin(), e = T->param_end();
398  i != e; ++i) {
399  FunctionType *FT;
400  if (isa<PointerType>(*i) && (FT = dyn_cast<FunctionType>(cast<PointerType>(
401  *i)->getElementType()))) {
402  ArgTypes.push_back(getTrampolineFunctionType(FT)->getPointerTo());
403  ArgTypes.push_back(Type::getInt8PtrTy(*Ctx));
404  } else {
405  ArgTypes.push_back(*i);
406  }
407  }
408  for (unsigned i = 0, e = T->getNumParams(); i != e; ++i)
409  ArgTypes.push_back(ShadowTy);
410  if (T->isVarArg())
411  ArgTypes.push_back(ShadowPtrTy);
412  Type *RetType = T->getReturnType();
413  if (!RetType->isVoidTy())
414  ArgTypes.push_back(ShadowPtrTy);
415  return FunctionType::get(T->getReturnType(), ArgTypes, T->isVarArg());
416 }
417 
418 bool DataFlowSanitizer::doInitialization(Module &M) {
419  llvm::Triple TargetTriple(M.getTargetTriple());
420  bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
421  bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
422  TargetTriple.getArch() == llvm::Triple::mips64el;
423 
424  const DataLayout &DL = M.getDataLayout();
425 
426  Mod = &M;
427  Ctx = &M.getContext();
428  ShadowTy = IntegerType::get(*Ctx, ShadowWidth);
429  ShadowPtrTy = PointerType::getUnqual(ShadowTy);
430  IntptrTy = DL.getIntPtrType(*Ctx);
431  ZeroShadow = ConstantInt::getSigned(ShadowTy, 0);
432  ShadowPtrMul = ConstantInt::getSigned(IntptrTy, ShadowWidth / 8);
433  if (IsX86_64)
434  ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0x700000000000LL);
435  else if (IsMIPS64)
436  ShadowPtrMask = ConstantInt::getSigned(IntptrTy, ~0xF000000000LL);
437  else
438  report_fatal_error("unsupported triple");
439 
440  Type *DFSanUnionArgs[2] = { ShadowTy, ShadowTy };
441  DFSanUnionFnTy =
442  FunctionType::get(ShadowTy, DFSanUnionArgs, /*isVarArg=*/ false);
443  Type *DFSanUnionLoadArgs[2] = { ShadowPtrTy, IntptrTy };
444  DFSanUnionLoadFnTy =
445  FunctionType::get(ShadowTy, DFSanUnionLoadArgs, /*isVarArg=*/ false);
446  DFSanUnimplementedFnTy = FunctionType::get(
447  Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
448  Type *DFSanSetLabelArgs[3] = { ShadowTy, Type::getInt8PtrTy(*Ctx), IntptrTy };
449  DFSanSetLabelFnTy = FunctionType::get(Type::getVoidTy(*Ctx),
450  DFSanSetLabelArgs, /*isVarArg=*/false);
451  DFSanNonzeroLabelFnTy = FunctionType::get(
452  Type::getVoidTy(*Ctx), None, /*isVarArg=*/false);
453  DFSanVarargWrapperFnTy = FunctionType::get(
454  Type::getVoidTy(*Ctx), Type::getInt8PtrTy(*Ctx), /*isVarArg=*/false);
455 
456  if (GetArgTLSPtr) {
457  Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
458  ArgTLS = nullptr;
459  GetArgTLS = ConstantExpr::getIntToPtr(
460  ConstantInt::get(IntptrTy, uintptr_t(GetArgTLSPtr)),
461  PointerType::getUnqual(
462  FunctionType::get(PointerType::getUnqual(ArgTLSTy),
463  (Type *)nullptr)));
464  }
465  if (GetRetvalTLSPtr) {
466  RetvalTLS = nullptr;
467  GetRetvalTLS = ConstantExpr::getIntToPtr(
468  ConstantInt::get(IntptrTy, uintptr_t(GetRetvalTLSPtr)),
469  PointerType::getUnqual(
470  FunctionType::get(PointerType::getUnqual(ShadowTy),
471  (Type *)nullptr)));
472  }
473 
474  ColdCallWeights = MDBuilder(*Ctx).createBranchWeights(1, 1000);
475  return true;
476 }
477 
478 bool DataFlowSanitizer::isInstrumented(const Function *F) {
479  return !ABIList.isIn(*F, "uninstrumented");
480 }
481 
482 bool DataFlowSanitizer::isInstrumented(const GlobalAlias *GA) {
483  return !ABIList.isIn(*GA, "uninstrumented");
484 }
485 
486 DataFlowSanitizer::InstrumentedABI DataFlowSanitizer::getInstrumentedABI() {
487  return ClArgsABI ? IA_Args : IA_TLS;
488 }
489 
490 DataFlowSanitizer::WrapperKind DataFlowSanitizer::getWrapperKind(Function *F) {
491  if (ABIList.isIn(*F, "functional"))
492  return WK_Functional;
493  if (ABIList.isIn(*F, "discard"))
494  return WK_Discard;
495  if (ABIList.isIn(*F, "custom"))
496  return WK_Custom;
497 
498  return WK_Warning;
499 }
500 
501 void DataFlowSanitizer::addGlobalNamePrefix(GlobalValue *GV) {
502  std::string GVName = GV->getName(), Prefix = "dfs$";
503  GV->setName(Prefix + GVName);
504 
505  // Try to change the name of the function in module inline asm. We only do
506  // this for specific asm directives, currently only ".symver", to try to avoid
507  // corrupting asm which happens to contain the symbol name as a substring.
508  // Note that the substitution for .symver assumes that the versioned symbol
509  // also has an instrumented name.
510  std::string Asm = GV->getParent()->getModuleInlineAsm();
511  std::string SearchStr = ".symver " + GVName + ",";
512  size_t Pos = Asm.find(SearchStr);
513  if (Pos != std::string::npos) {
514  Asm.replace(Pos, SearchStr.size(),
515  ".symver " + Prefix + GVName + "," + Prefix);
516  GV->getParent()->setModuleInlineAsm(Asm);
517  }
518 }
519 
520 Function *
521 DataFlowSanitizer::buildWrapperFunction(Function *F, StringRef NewFName,
522  GlobalValue::LinkageTypes NewFLink,
523  FunctionType *NewFT) {
524  FunctionType *FT = F->getFunctionType();
525  Function *NewF = Function::Create(NewFT, NewFLink, NewFName,
526  F->getParent());
527  NewF->copyAttributesFrom(F);
528  NewF->removeAttributes(
529  AttributeSet::ReturnIndex,
530  AttributeSet::get(F->getContext(), AttributeSet::ReturnIndex,
532 
533  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", NewF);
534  if (F->isVarArg()) {
535  NewF->removeAttributes(
536  AttributeSet::FunctionIndex,
537  AttributeSet().addAttribute(*Ctx, AttributeSet::FunctionIndex,
538  "split-stack"));
539  CallInst::Create(DFSanVarargWrapperFn,
540  IRBuilder<>(BB).CreateGlobalStringPtr(F->getName()), "",
541  BB);
542  new UnreachableInst(*Ctx, BB);
543  } else {
544  std::vector<Value *> Args;
545  unsigned n = FT->getNumParams();
546  for (Function::arg_iterator ai = NewF->arg_begin(); n != 0; ++ai, --n)
547  Args.push_back(&*ai);
548  CallInst *CI = CallInst::Create(F, Args, "", BB);
549  if (FT->getReturnType()->isVoidTy())
550  ReturnInst::Create(*Ctx, BB);
551  else
552  ReturnInst::Create(*Ctx, CI, BB);
553  }
554 
555  return NewF;
556 }
557 
558 Constant *DataFlowSanitizer::getOrBuildTrampolineFunction(FunctionType *FT,
559  StringRef FName) {
560  FunctionType *FTT = getTrampolineFunctionType(FT);
561  Constant *C = Mod->getOrInsertFunction(FName, FTT);
562  Function *F = dyn_cast<Function>(C);
563  if (F && F->isDeclaration()) {
564  F->setLinkage(GlobalValue::LinkOnceODRLinkage);
565  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
566  std::vector<Value *> Args;
567  Function::arg_iterator AI = F->arg_begin(); ++AI;
568  for (unsigned N = FT->getNumParams(); N != 0; ++AI, --N)
569  Args.push_back(&*AI);
570  CallInst *CI =
571  CallInst::Create(&F->getArgumentList().front(), Args, "", BB);
572  ReturnInst *RI;
573  if (FT->getReturnType()->isVoidTy())
574  RI = ReturnInst::Create(*Ctx, BB);
575  else
576  RI = ReturnInst::Create(*Ctx, CI, BB);
577 
578  DFSanFunction DFSF(*this, F, /*IsNativeABI=*/true);
579  Function::arg_iterator ValAI = F->arg_begin(), ShadowAI = AI; ++ValAI;
580  for (unsigned N = FT->getNumParams(); N != 0; ++ValAI, ++ShadowAI, --N)
581  DFSF.ValShadowMap[ValAI] = ShadowAI;
582  DFSanVisitor(DFSF).visitCallInst(*CI);
583  if (!FT->getReturnType()->isVoidTy())
584  new StoreInst(DFSF.getShadow(RI->getReturnValue()),
585  &F->getArgumentList().back(), RI);
586  }
587 
588  return C;
589 }
590 
591 bool DataFlowSanitizer::runOnModule(Module &M) {
592  if (ABIList.isIn(M, "skip"))
593  return false;
594 
595  FunctionDIs = makeSubprogramMap(M);
596 
597  if (!GetArgTLSPtr) {
598  Type *ArgTLSTy = ArrayType::get(ShadowTy, 64);
599  ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy);
600  if (GlobalVariable *G = dyn_cast<GlobalVariable>(ArgTLS))
601  G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
602  }
603  if (!GetRetvalTLSPtr) {
604  RetvalTLS = Mod->getOrInsertGlobal("__dfsan_retval_tls", ShadowTy);
605  if (GlobalVariable *G = dyn_cast<GlobalVariable>(RetvalTLS))
606  G->setThreadLocalMode(GlobalVariable::InitialExecTLSModel);
607  }
608 
609  DFSanUnionFn = Mod->getOrInsertFunction("__dfsan_union", DFSanUnionFnTy);
610  if (Function *F = dyn_cast<Function>(DFSanUnionFn)) {
611  F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
612  F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
613  F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
614  F->addAttribute(1, Attribute::ZExt);
615  F->addAttribute(2, Attribute::ZExt);
616  }
617  DFSanCheckedUnionFn = Mod->getOrInsertFunction("dfsan_union", DFSanUnionFnTy);
618  if (Function *F = dyn_cast<Function>(DFSanCheckedUnionFn)) {
619  F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
620  F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadNone);
621  F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
622  F->addAttribute(1, Attribute::ZExt);
623  F->addAttribute(2, Attribute::ZExt);
624  }
625  DFSanUnionLoadFn =
626  Mod->getOrInsertFunction("__dfsan_union_load", DFSanUnionLoadFnTy);
627  if (Function *F = dyn_cast<Function>(DFSanUnionLoadFn)) {
628  F->addAttribute(AttributeSet::FunctionIndex, Attribute::NoUnwind);
629  F->addAttribute(AttributeSet::FunctionIndex, Attribute::ReadOnly);
630  F->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
631  }
632  DFSanUnimplementedFn =
633  Mod->getOrInsertFunction("__dfsan_unimplemented", DFSanUnimplementedFnTy);
634  DFSanSetLabelFn =
635  Mod->getOrInsertFunction("__dfsan_set_label", DFSanSetLabelFnTy);
636  if (Function *F = dyn_cast<Function>(DFSanSetLabelFn)) {
637  F->addAttribute(1, Attribute::ZExt);
638  }
639  DFSanNonzeroLabelFn =
640  Mod->getOrInsertFunction("__dfsan_nonzero_label", DFSanNonzeroLabelFnTy);
641  DFSanVarargWrapperFn = Mod->getOrInsertFunction("__dfsan_vararg_wrapper",
642  DFSanVarargWrapperFnTy);
643 
644  std::vector<Function *> FnsToInstrument;
645  llvm::SmallPtrSet<Function *, 2> FnsWithNativeABI;
646  for (Module::iterator i = M.begin(), e = M.end(); i != e; ++i) {
647  if (!i->isIntrinsic() &&
648  i != DFSanUnionFn &&
649  i != DFSanCheckedUnionFn &&
650  i != DFSanUnionLoadFn &&
651  i != DFSanUnimplementedFn &&
652  i != DFSanSetLabelFn &&
653  i != DFSanNonzeroLabelFn &&
654  i != DFSanVarargWrapperFn)
655  FnsToInstrument.push_back(&*i);
656  }
657 
658  // Give function aliases prefixes when necessary, and build wrappers where the
659  // instrumentedness is inconsistent.
660  for (Module::alias_iterator i = M.alias_begin(), e = M.alias_end(); i != e;) {
661  GlobalAlias *GA = &*i;
662  ++i;
663  // Don't stop on weak. We assume people aren't playing games with the
664  // instrumentedness of overridden weak aliases.
665  if (auto F = dyn_cast<Function>(GA->getBaseObject())) {
666  bool GAInst = isInstrumented(GA), FInst = isInstrumented(F);
667  if (GAInst && FInst) {
668  addGlobalNamePrefix(GA);
669  } else if (GAInst != FInst) {
670  // Non-instrumented alias of an instrumented function, or vice versa.
671  // Replace the alias with a native-ABI wrapper of the aliasee. The pass
672  // below will take care of instrumenting it.
673  Function *NewF =
674  buildWrapperFunction(F, "", GA->getLinkage(), F->getFunctionType());
675  GA->replaceAllUsesWith(ConstantExpr::getBitCast(NewF, GA->getType()));
676  NewF->takeName(GA);
677  GA->eraseFromParent();
678  FnsToInstrument.push_back(NewF);
679  }
680  }
681  }
682 
683  AttrBuilder B;
684  B.addAttribute(Attribute::ReadOnly).addAttribute(Attribute::ReadNone);
685  ReadOnlyNoneAttrs = AttributeSet::get(*Ctx, AttributeSet::FunctionIndex, B);
686 
687  // First, change the ABI of every function in the module. ABI-listed
688  // functions keep their original ABI and get a wrapper function.
689  for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
690  e = FnsToInstrument.end();
691  i != e; ++i) {
692  Function &F = **i;
693  FunctionType *FT = F.getFunctionType();
694 
695  bool IsZeroArgsVoidRet = (FT->getNumParams() == 0 && !FT->isVarArg() &&
696  FT->getReturnType()->isVoidTy());
697 
698  if (isInstrumented(&F)) {
699  // Instrumented functions get a 'dfs$' prefix. This allows us to more
700  // easily identify cases of mismatching ABIs.
701  if (getInstrumentedABI() == IA_Args && !IsZeroArgsVoidRet) {
702  FunctionType *NewFT = getArgsFunctionType(FT);
703  Function *NewF = Function::Create(NewFT, F.getLinkage(), "", &M);
704  NewF->copyAttributesFrom(&F);
705  NewF->removeAttributes(
706  AttributeSet::ReturnIndex,
707  AttributeSet::get(NewF->getContext(), AttributeSet::ReturnIndex,
709  for (Function::arg_iterator FArg = F.arg_begin(),
710  NewFArg = NewF->arg_begin(),
711  FArgEnd = F.arg_end();
712  FArg != FArgEnd; ++FArg, ++NewFArg) {
713  FArg->replaceAllUsesWith(NewFArg);
714  }
715  NewF->getBasicBlockList().splice(NewF->begin(), F.getBasicBlockList());
716 
717  for (Function::user_iterator UI = F.user_begin(), UE = F.user_end();
718  UI != UE;) {
719  BlockAddress *BA = dyn_cast<BlockAddress>(*UI);
720  ++UI;
721  if (BA) {
722  BA->replaceAllUsesWith(
723  BlockAddress::get(NewF, BA->getBasicBlock()));
724  delete BA;
725  }
726  }
728  ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT)));
729  NewF->takeName(&F);
730  F.eraseFromParent();
731  *i = NewF;
732  addGlobalNamePrefix(NewF);
733  } else {
734  addGlobalNamePrefix(&F);
735  }
736  } else if (!IsZeroArgsVoidRet || getWrapperKind(&F) == WK_Custom) {
737  // Build a wrapper function for F. The wrapper simply calls F, and is
738  // added to FnsToInstrument so that any instrumentation according to its
739  // WrapperKind is done in the second pass below.
740  FunctionType *NewFT = getInstrumentedABI() == IA_Args
741  ? getArgsFunctionType(FT)
742  : FT;
743  Function *NewF = buildWrapperFunction(
744  &F, std::string("dfsw$") + std::string(F.getName()),
745  GlobalValue::LinkOnceODRLinkage, NewFT);
746  if (getInstrumentedABI() == IA_TLS)
747  NewF->removeAttributes(AttributeSet::FunctionIndex, ReadOnlyNoneAttrs);
748 
749  Value *WrappedFnCst =
750  ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT));
751  F.replaceAllUsesWith(WrappedFnCst);
752 
753  // Patch the pointer to LLVM function in debug info descriptor.
754  auto DI = FunctionDIs.find(&F);
755  if (DI != FunctionDIs.end())
756  DI->second->replaceFunction(&F);
757 
758  UnwrappedFnMap[WrappedFnCst] = &F;
759  *i = NewF;
760 
761  if (!F.isDeclaration()) {
762  // This function is probably defining an interposition of an
763  // uninstrumented function and hence needs to keep the original ABI.
764  // But any functions it may call need to use the instrumented ABI, so
765  // we instrument it in a mode which preserves the original ABI.
766  FnsWithNativeABI.insert(&F);
767 
768  // This code needs to rebuild the iterators, as they may be invalidated
769  // by the push_back, taking care that the new range does not include
770  // any functions added by this code.
771  size_t N = i - FnsToInstrument.begin(),
772  Count = e - FnsToInstrument.begin();
773  FnsToInstrument.push_back(&F);
774  i = FnsToInstrument.begin() + N;
775  e = FnsToInstrument.begin() + Count;
776  }
777  // Hopefully, nobody will try to indirectly call a vararg
778  // function... yet.
779  } else if (FT->isVarArg()) {
780  UnwrappedFnMap[&F] = &F;
781  *i = nullptr;
782  }
783  }
784 
785  for (std::vector<Function *>::iterator i = FnsToInstrument.begin(),
786  e = FnsToInstrument.end();
787  i != e; ++i) {
788  if (!*i || (*i)->isDeclaration())
789  continue;
790 
792 
793  DFSanFunction DFSF(*this, *i, FnsWithNativeABI.count(*i));
794 
795  // DFSanVisitor may create new basic blocks, which confuses df_iterator.
796  // Build a copy of the list before iterating over it.
798  depth_first(&(*i)->getEntryBlock()));
799 
800  for (llvm::SmallVector<BasicBlock *, 4>::iterator i = BBList.begin(),
801  e = BBList.end();
802  i != e; ++i) {
803  Instruction *Inst = &(*i)->front();
804  while (1) {
805  // DFSanVisitor may split the current basic block, changing the current
806  // instruction's next pointer and moving the next instruction to the
807  // tail block from which we should continue.
808  Instruction *Next = Inst->getNextNode();
809  // DFSanVisitor may delete Inst, so keep track of whether it was a
810  // terminator.
811  bool IsTerminator = isa<TerminatorInst>(Inst);
812  if (!DFSF.SkipInsts.count(Inst))
813  DFSanVisitor(DFSF).visit(Inst);
814  if (IsTerminator)
815  break;
816  Inst = Next;
817  }
818  }
819 
820  // We will not necessarily be able to compute the shadow for every phi node
821  // until we have visited every block. Therefore, the code that handles phi
822  // nodes adds them to the PHIFixups list so that they can be properly
823  // handled here.
824  for (std::vector<std::pair<PHINode *, PHINode *> >::iterator
825  i = DFSF.PHIFixups.begin(),
826  e = DFSF.PHIFixups.end();
827  i != e; ++i) {
828  for (unsigned val = 0, n = i->first->getNumIncomingValues(); val != n;
829  ++val) {
830  i->second->setIncomingValue(
831  val, DFSF.getShadow(i->first->getIncomingValue(val)));
832  }
833  }
834 
835  // -dfsan-debug-nonzero-labels will split the CFG in all kinds of crazy
836  // places (i.e. instructions in basic blocks we haven't even begun visiting
837  // yet). To make our life easier, do this work in a pass after the main
838  // instrumentation.
839  if (ClDebugNonzeroLabels) {
840  for (Value *V : DFSF.NonZeroChecks) {
841  Instruction *Pos;
842  if (Instruction *I = dyn_cast<Instruction>(V))
843  Pos = I->getNextNode();
844  else
845  Pos = DFSF.F->getEntryBlock().begin();
846  while (isa<PHINode>(Pos) || isa<AllocaInst>(Pos))
847  Pos = Pos->getNextNode();
848  IRBuilder<> IRB(Pos);
849  Value *Ne = IRB.CreateICmpNE(V, DFSF.DFS.ZeroShadow);
850  BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
851  Ne, Pos, /*Unreachable=*/false, ColdCallWeights));
852  IRBuilder<> ThenIRB(BI);
853  ThenIRB.CreateCall(DFSF.DFS.DFSanNonzeroLabelFn, {});
854  }
855  }
856  }
857 
858  return false;
859 }
860 
861 Value *DFSanFunction::getArgTLSPtr() {
862  if (ArgTLSPtr)
863  return ArgTLSPtr;
864  if (DFS.ArgTLS)
865  return ArgTLSPtr = DFS.ArgTLS;
866 
867  IRBuilder<> IRB(F->getEntryBlock().begin());
868  return ArgTLSPtr = IRB.CreateCall(DFS.GetArgTLS, {});
869 }
870 
871 Value *DFSanFunction::getRetvalTLS() {
872  if (RetvalTLSPtr)
873  return RetvalTLSPtr;
874  if (DFS.RetvalTLS)
875  return RetvalTLSPtr = DFS.RetvalTLS;
876 
877  IRBuilder<> IRB(F->getEntryBlock().begin());
878  return RetvalTLSPtr = IRB.CreateCall(DFS.GetRetvalTLS, {});
879 }
880 
881 Value *DFSanFunction::getArgTLS(unsigned Idx, Instruction *Pos) {
882  IRBuilder<> IRB(Pos);
883  return IRB.CreateConstGEP2_64(getArgTLSPtr(), 0, Idx);
884 }
885 
886 Value *DFSanFunction::getShadow(Value *V) {
887  if (!isa<Argument>(V) && !isa<Instruction>(V))
888  return DFS.ZeroShadow;
889  Value *&Shadow = ValShadowMap[V];
890  if (!Shadow) {
891  if (Argument *A = dyn_cast<Argument>(V)) {
892  if (IsNativeABI)
893  return DFS.ZeroShadow;
894  switch (IA) {
895  case DataFlowSanitizer::IA_TLS: {
896  Value *ArgTLSPtr = getArgTLSPtr();
897  Instruction *ArgTLSPos =
898  DFS.ArgTLS ? &*F->getEntryBlock().begin()
899  : cast<Instruction>(ArgTLSPtr)->getNextNode();
900  IRBuilder<> IRB(ArgTLSPos);
901  Shadow = IRB.CreateLoad(getArgTLS(A->getArgNo(), ArgTLSPos));
902  break;
903  }
904  case DataFlowSanitizer::IA_Args: {
905  unsigned ArgIdx = A->getArgNo() + F->getArgumentList().size() / 2;
907  while (ArgIdx--)
908  ++i;
909  Shadow = i;
910  assert(Shadow->getType() == DFS.ShadowTy);
911  break;
912  }
913  }
914  NonZeroChecks.push_back(Shadow);
915  } else {
916  Shadow = DFS.ZeroShadow;
917  }
918  }
919  return Shadow;
920 }
921 
922 void DFSanFunction::setShadow(Instruction *I, Value *Shadow) {
923  assert(!ValShadowMap.count(I));
924  assert(Shadow->getType() == DFS.ShadowTy);
925  ValShadowMap[I] = Shadow;
926 }
927 
928 Value *DataFlowSanitizer::getShadowAddress(Value *Addr, Instruction *Pos) {
929  assert(Addr != RetvalTLS && "Reinstrumenting?");
930  IRBuilder<> IRB(Pos);
931  return IRB.CreateIntToPtr(
932  IRB.CreateMul(
933  IRB.CreateAnd(IRB.CreatePtrToInt(Addr, IntptrTy), ShadowPtrMask),
934  ShadowPtrMul),
935  ShadowPtrTy);
936 }
937 
938 // Generates IR to compute the union of the two given shadows, inserting it
939 // before Pos. Returns the computed union Value.
940 Value *DFSanFunction::combineShadows(Value *V1, Value *V2, Instruction *Pos) {
941  if (V1 == DFS.ZeroShadow)
942  return V2;
943  if (V2 == DFS.ZeroShadow)
944  return V1;
945  if (V1 == V2)
946  return V1;
947 
948  auto V1Elems = ShadowElements.find(V1);
949  auto V2Elems = ShadowElements.find(V2);
950  if (V1Elems != ShadowElements.end() && V2Elems != ShadowElements.end()) {
951  if (std::includes(V1Elems->second.begin(), V1Elems->second.end(),
952  V2Elems->second.begin(), V2Elems->second.end())) {
953  return V1;
954  } else if (std::includes(V2Elems->second.begin(), V2Elems->second.end(),
955  V1Elems->second.begin(), V1Elems->second.end())) {
956  return V2;
957  }
958  } else if (V1Elems != ShadowElements.end()) {
959  if (V1Elems->second.count(V2))
960  return V1;
961  } else if (V2Elems != ShadowElements.end()) {
962  if (V2Elems->second.count(V1))
963  return V2;
964  }
965 
966  auto Key = std::make_pair(V1, V2);
967  if (V1 > V2)
968  std::swap(Key.first, Key.second);
969  CachedCombinedShadow &CCS = CachedCombinedShadows[Key];
970  if (CCS.Block && DT.dominates(CCS.Block, Pos->getParent()))
971  return CCS.Shadow;
972 
973  IRBuilder<> IRB(Pos);
974  if (AvoidNewBlocks) {
975  CallInst *Call = IRB.CreateCall(DFS.DFSanCheckedUnionFn, {V1, V2});
976  Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
977  Call->addAttribute(1, Attribute::ZExt);
978  Call->addAttribute(2, Attribute::ZExt);
979 
980  CCS.Block = Pos->getParent();
981  CCS.Shadow = Call;
982  } else {
983  BasicBlock *Head = Pos->getParent();
984  Value *Ne = IRB.CreateICmpNE(V1, V2);
985  BranchInst *BI = cast<BranchInst>(SplitBlockAndInsertIfThen(
986  Ne, Pos, /*Unreachable=*/false, DFS.ColdCallWeights, &DT));
987  IRBuilder<> ThenIRB(BI);
988  CallInst *Call = ThenIRB.CreateCall(DFS.DFSanUnionFn, {V1, V2});
989  Call->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
990  Call->addAttribute(1, Attribute::ZExt);
991  Call->addAttribute(2, Attribute::ZExt);
992 
993  BasicBlock *Tail = BI->getSuccessor(0);
994  PHINode *Phi = PHINode::Create(DFS.ShadowTy, 2, "", Tail->begin());
995  Phi->addIncoming(Call, Call->getParent());
996  Phi->addIncoming(V1, Head);
997 
998  CCS.Block = Tail;
999  CCS.Shadow = Phi;
1000  }
1001 
1002  std::set<Value *> UnionElems;
1003  if (V1Elems != ShadowElements.end()) {
1004  UnionElems = V1Elems->second;
1005  } else {
1006  UnionElems.insert(V1);
1007  }
1008  if (V2Elems != ShadowElements.end()) {
1009  UnionElems.insert(V2Elems->second.begin(), V2Elems->second.end());
1010  } else {
1011  UnionElems.insert(V2);
1012  }
1013  ShadowElements[CCS.Shadow] = std::move(UnionElems);
1014 
1015  return CCS.Shadow;
1016 }
1017 
1018 // A convenience function which folds the shadows of each of the operands
1019 // of the provided instruction Inst, inserting the IR before Inst. Returns
1020 // the computed union Value.
1021 Value *DFSanFunction::combineOperandShadows(Instruction *Inst) {
1022  if (Inst->getNumOperands() == 0)
1023  return DFS.ZeroShadow;
1024 
1025  Value *Shadow = getShadow(Inst->getOperand(0));
1026  for (unsigned i = 1, n = Inst->getNumOperands(); i != n; ++i) {
1027  Shadow = combineShadows(Shadow, getShadow(Inst->getOperand(i)), Inst);
1028  }
1029  return Shadow;
1030 }
1031 
1032 void DFSanVisitor::visitOperandShadowInst(Instruction &I) {
1033  Value *CombinedShadow = DFSF.combineOperandShadows(&I);
1034  DFSF.setShadow(&I, CombinedShadow);
1035 }
1036 
1037 // Generates IR to load shadow corresponding to bytes [Addr, Addr+Size), where
1038 // Addr has alignment Align, and take the union of each of those shadows.
1039 Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
1040  Instruction *Pos) {
1041  if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
1043  AllocaShadowMap.find(AI);
1044  if (i != AllocaShadowMap.end()) {
1045  IRBuilder<> IRB(Pos);
1046  return IRB.CreateLoad(i->second);
1047  }
1048  }
1049 
1050  uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
1052  GetUnderlyingObjects(Addr, Objs, Pos->getModule()->getDataLayout());
1053  bool AllConstants = true;
1054  for (SmallVector<Value *, 2>::iterator i = Objs.begin(), e = Objs.end();
1055  i != e; ++i) {
1056  if (isa<Function>(*i) || isa<BlockAddress>(*i))
1057  continue;
1058  if (isa<GlobalVariable>(*i) && cast<GlobalVariable>(*i)->isConstant())
1059  continue;
1060 
1061  AllConstants = false;
1062  break;
1063  }
1064  if (AllConstants)
1065  return DFS.ZeroShadow;
1066 
1067  Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
1068  switch (Size) {
1069  case 0:
1070  return DFS.ZeroShadow;
1071  case 1: {
1072  LoadInst *LI = new LoadInst(ShadowAddr, "", Pos);
1073  LI->setAlignment(ShadowAlign);
1074  return LI;
1075  }
1076  case 2: {
1077  IRBuilder<> IRB(Pos);
1078  Value *ShadowAddr1 = IRB.CreateGEP(DFS.ShadowTy, ShadowAddr,
1079  ConstantInt::get(DFS.IntptrTy, 1));
1080  return combineShadows(IRB.CreateAlignedLoad(ShadowAddr, ShadowAlign),
1081  IRB.CreateAlignedLoad(ShadowAddr1, ShadowAlign), Pos);
1082  }
1083  }
1084  if (!AvoidNewBlocks && Size % (64 / DFS.ShadowWidth) == 0) {
1085  // Fast path for the common case where each byte has identical shadow: load
1086  // shadow 64 bits at a time, fall out to a __dfsan_union_load call if any
1087  // shadow is non-equal.
1088  BasicBlock *FallbackBB = BasicBlock::Create(*DFS.Ctx, "", F);
1089  IRBuilder<> FallbackIRB(FallbackBB);
1090  CallInst *FallbackCall = FallbackIRB.CreateCall(
1091  DFS.DFSanUnionLoadFn,
1092  {ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size)});
1093  FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
1094 
1095  // Compare each of the shadows stored in the loaded 64 bits to each other,
1096  // by computing (WideShadow rotl ShadowWidth) == WideShadow.
1097  IRBuilder<> IRB(Pos);
1098  Value *WideAddr =
1099  IRB.CreateBitCast(ShadowAddr, Type::getInt64PtrTy(*DFS.Ctx));
1100  Value *WideShadow = IRB.CreateAlignedLoad(WideAddr, ShadowAlign);
1101  Value *TruncShadow = IRB.CreateTrunc(WideShadow, DFS.ShadowTy);
1102  Value *ShlShadow = IRB.CreateShl(WideShadow, DFS.ShadowWidth);
1103  Value *ShrShadow = IRB.CreateLShr(WideShadow, 64 - DFS.ShadowWidth);
1104  Value *RotShadow = IRB.CreateOr(ShlShadow, ShrShadow);
1105  Value *ShadowsEq = IRB.CreateICmpEQ(WideShadow, RotShadow);
1106 
1107  BasicBlock *Head = Pos->getParent();
1108  BasicBlock *Tail = Head->splitBasicBlock(Pos);
1109 
1110  if (DomTreeNode *OldNode = DT.getNode(Head)) {
1111  std::vector<DomTreeNode *> Children(OldNode->begin(), OldNode->end());
1112 
1113  DomTreeNode *NewNode = DT.addNewBlock(Tail, Head);
1114  for (auto Child : Children)
1115  DT.changeImmediateDominator(Child, NewNode);
1116  }
1117 
1118  // In the following code LastBr will refer to the previous basic block's
1119  // conditional branch instruction, whose true successor is fixed up to point
1120  // to the next block during the loop below or to the tail after the final
1121  // iteration.
1122  BranchInst *LastBr = BranchInst::Create(FallbackBB, FallbackBB, ShadowsEq);
1123  ReplaceInstWithInst(Head->getTerminator(), LastBr);
1124  DT.addNewBlock(FallbackBB, Head);
1125 
1126  for (uint64_t Ofs = 64 / DFS.ShadowWidth; Ofs != Size;
1127  Ofs += 64 / DFS.ShadowWidth) {
1128  BasicBlock *NextBB = BasicBlock::Create(*DFS.Ctx, "", F);
1129  DT.addNewBlock(NextBB, LastBr->getParent());
1130  IRBuilder<> NextIRB(NextBB);
1131  WideAddr = NextIRB.CreateGEP(Type::getInt64Ty(*DFS.Ctx), WideAddr,
1132  ConstantInt::get(DFS.IntptrTy, 1));
1133  Value *NextWideShadow = NextIRB.CreateAlignedLoad(WideAddr, ShadowAlign);
1134  ShadowsEq = NextIRB.CreateICmpEQ(WideShadow, NextWideShadow);
1135  LastBr->setSuccessor(0, NextBB);
1136  LastBr = NextIRB.CreateCondBr(ShadowsEq, FallbackBB, FallbackBB);
1137  }
1138 
1139  LastBr->setSuccessor(0, Tail);
1140  FallbackIRB.CreateBr(Tail);
1141  PHINode *Shadow = PHINode::Create(DFS.ShadowTy, 2, "", &Tail->front());
1142  Shadow->addIncoming(FallbackCall, FallbackBB);
1143  Shadow->addIncoming(TruncShadow, LastBr->getParent());
1144  return Shadow;
1145  }
1146 
1147  IRBuilder<> IRB(Pos);
1148  CallInst *FallbackCall = IRB.CreateCall(
1149  DFS.DFSanUnionLoadFn, {ShadowAddr, ConstantInt::get(DFS.IntptrTy, Size)});
1150  FallbackCall->addAttribute(AttributeSet::ReturnIndex, Attribute::ZExt);
1151  return FallbackCall;
1152 }
1153 
1154 void DFSanVisitor::visitLoadInst(LoadInst &LI) {
1155  auto &DL = LI.getModule()->getDataLayout();
1156  uint64_t Size = DL.getTypeStoreSize(LI.getType());
1157  if (Size == 0) {
1158  DFSF.setShadow(&LI, DFSF.DFS.ZeroShadow);
1159  return;
1160  }
1161 
1162  uint64_t Align;
1163  if (ClPreserveAlignment) {
1164  Align = LI.getAlignment();
1165  if (Align == 0)
1166  Align = DL.getABITypeAlignment(LI.getType());
1167  } else {
1168  Align = 1;
1169  }
1170  IRBuilder<> IRB(&LI);
1171  Value *Shadow = DFSF.loadShadow(LI.getPointerOperand(), Size, Align, &LI);
1173  Value *PtrShadow = DFSF.getShadow(LI.getPointerOperand());
1174  Shadow = DFSF.combineShadows(Shadow, PtrShadow, &LI);
1175  }
1176  if (Shadow != DFSF.DFS.ZeroShadow)
1177  DFSF.NonZeroChecks.push_back(Shadow);
1178 
1179  DFSF.setShadow(&LI, Shadow);
1180 }
1181 
1182 void DFSanFunction::storeShadow(Value *Addr, uint64_t Size, uint64_t Align,
1183  Value *Shadow, Instruction *Pos) {
1184  if (AllocaInst *AI = dyn_cast<AllocaInst>(Addr)) {
1186  AllocaShadowMap.find(AI);
1187  if (i != AllocaShadowMap.end()) {
1188  IRBuilder<> IRB(Pos);
1189  IRB.CreateStore(Shadow, i->second);
1190  return;
1191  }
1192  }
1193 
1194  uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
1195  IRBuilder<> IRB(Pos);
1196  Value *ShadowAddr = DFS.getShadowAddress(Addr, Pos);
1197  if (Shadow == DFS.ZeroShadow) {
1198  IntegerType *ShadowTy = IntegerType::get(*DFS.Ctx, Size * DFS.ShadowWidth);
1199  Value *ExtZeroShadow = ConstantInt::get(ShadowTy, 0);
1200  Value *ExtShadowAddr =
1201  IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowTy));
1202  IRB.CreateAlignedStore(ExtZeroShadow, ExtShadowAddr, ShadowAlign);
1203  return;
1204  }
1205 
1206  const unsigned ShadowVecSize = 128 / DFS.ShadowWidth;
1207  uint64_t Offset = 0;
1208  if (Size >= ShadowVecSize) {
1209  VectorType *ShadowVecTy = VectorType::get(DFS.ShadowTy, ShadowVecSize);
1210  Value *ShadowVec = UndefValue::get(ShadowVecTy);
1211  for (unsigned i = 0; i != ShadowVecSize; ++i) {
1212  ShadowVec = IRB.CreateInsertElement(
1213  ShadowVec, Shadow, ConstantInt::get(Type::getInt32Ty(*DFS.Ctx), i));
1214  }
1215  Value *ShadowVecAddr =
1216  IRB.CreateBitCast(ShadowAddr, PointerType::getUnqual(ShadowVecTy));
1217  do {
1218  Value *CurShadowVecAddr =
1219  IRB.CreateConstGEP1_32(ShadowVecTy, ShadowVecAddr, Offset);
1220  IRB.CreateAlignedStore(ShadowVec, CurShadowVecAddr, ShadowAlign);
1221  Size -= ShadowVecSize;
1222  ++Offset;
1223  } while (Size >= ShadowVecSize);
1224  Offset *= ShadowVecSize;
1225  }
1226  while (Size > 0) {
1227  Value *CurShadowAddr =
1228  IRB.CreateConstGEP1_32(DFS.ShadowTy, ShadowAddr, Offset);
1229  IRB.CreateAlignedStore(Shadow, CurShadowAddr, ShadowAlign);
1230  --Size;
1231  ++Offset;
1232  }
1233 }
1234 
1235 void DFSanVisitor::visitStoreInst(StoreInst &SI) {
1236  auto &DL = SI.getModule()->getDataLayout();
1237  uint64_t Size = DL.getTypeStoreSize(SI.getValueOperand()->getType());
1238  if (Size == 0)
1239  return;
1240 
1241  uint64_t Align;
1242  if (ClPreserveAlignment) {
1243  Align = SI.getAlignment();
1244  if (Align == 0)
1245  Align = DL.getABITypeAlignment(SI.getValueOperand()->getType());
1246  } else {
1247  Align = 1;
1248  }
1249 
1250  Value* Shadow = DFSF.getShadow(SI.getValueOperand());
1252  Value *PtrShadow = DFSF.getShadow(SI.getPointerOperand());
1253  Shadow = DFSF.combineShadows(Shadow, PtrShadow, &SI);
1254  }
1255  DFSF.storeShadow(SI.getPointerOperand(), Size, Align, Shadow, &SI);
1256 }
1257 
1258 void DFSanVisitor::visitBinaryOperator(BinaryOperator &BO) {
1259  visitOperandShadowInst(BO);
1260 }
1261 
1262 void DFSanVisitor::visitCastInst(CastInst &CI) { visitOperandShadowInst(CI); }
1263 
1264 void DFSanVisitor::visitCmpInst(CmpInst &CI) { visitOperandShadowInst(CI); }
1265 
1266 void DFSanVisitor::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
1267  visitOperandShadowInst(GEPI);
1268 }
1269 
1270 void DFSanVisitor::visitExtractElementInst(ExtractElementInst &I) {
1271  visitOperandShadowInst(I);
1272 }
1273 
1274 void DFSanVisitor::visitInsertElementInst(InsertElementInst &I) {
1275  visitOperandShadowInst(I);
1276 }
1277 
1278 void DFSanVisitor::visitShuffleVectorInst(ShuffleVectorInst &I) {
1279  visitOperandShadowInst(I);
1280 }
1281 
1282 void DFSanVisitor::visitExtractValueInst(ExtractValueInst &I) {
1283  visitOperandShadowInst(I);
1284 }
1285 
1286 void DFSanVisitor::visitInsertValueInst(InsertValueInst &I) {
1287  visitOperandShadowInst(I);
1288 }
1289 
1290 void DFSanVisitor::visitAllocaInst(AllocaInst &I) {
1291  bool AllLoadsStores = true;
1292  for (User *U : I.users()) {
1293  if (isa<LoadInst>(U))
1294  continue;
1295 
1296  if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
1297  if (SI->getPointerOperand() == &I)
1298  continue;
1299  }
1300 
1301  AllLoadsStores = false;
1302  break;
1303  }
1304  if (AllLoadsStores) {
1305  IRBuilder<> IRB(&I);
1306  DFSF.AllocaShadowMap[&I] = IRB.CreateAlloca(DFSF.DFS.ShadowTy);
1307  }
1308  DFSF.setShadow(&I, DFSF.DFS.ZeroShadow);
1309 }
1310 
1311 void DFSanVisitor::visitSelectInst(SelectInst &I) {
1312  Value *CondShadow = DFSF.getShadow(I.getCondition());
1313  Value *TrueShadow = DFSF.getShadow(I.getTrueValue());
1314  Value *FalseShadow = DFSF.getShadow(I.getFalseValue());
1315 
1316  if (isa<VectorType>(I.getCondition()->getType())) {
1317  DFSF.setShadow(
1318  &I,
1319  DFSF.combineShadows(
1320  CondShadow, DFSF.combineShadows(TrueShadow, FalseShadow, &I), &I));
1321  } else {
1322  Value *ShadowSel;
1323  if (TrueShadow == FalseShadow) {
1324  ShadowSel = TrueShadow;
1325  } else {
1326  ShadowSel =
1327  SelectInst::Create(I.getCondition(), TrueShadow, FalseShadow, "", &I);
1328  }
1329  DFSF.setShadow(&I, DFSF.combineShadows(CondShadow, ShadowSel, &I));
1330  }
1331 }
1332 
1333 void DFSanVisitor::visitMemSetInst(MemSetInst &I) {
1334  IRBuilder<> IRB(&I);
1335  Value *ValShadow = DFSF.getShadow(I.getValue());
1336  IRB.CreateCall(DFSF.DFS.DFSanSetLabelFn,
1337  {ValShadow, IRB.CreateBitCast(I.getDest(), Type::getInt8PtrTy(
1338  *DFSF.DFS.Ctx)),
1339  IRB.CreateZExtOrTrunc(I.getLength(), DFSF.DFS.IntptrTy)});
1340 }
1341 
1342 void DFSanVisitor::visitMemTransferInst(MemTransferInst &I) {
1343  IRBuilder<> IRB(&I);
1344  Value *DestShadow = DFSF.DFS.getShadowAddress(I.getDest(), &I);
1345  Value *SrcShadow = DFSF.DFS.getShadowAddress(I.getSource(), &I);
1346  Value *LenShadow = IRB.CreateMul(
1347  I.getLength(),
1348  ConstantInt::get(I.getLength()->getType(), DFSF.DFS.ShadowWidth / 8));
1349  Value *AlignShadow;
1350  if (ClPreserveAlignment) {
1351  AlignShadow = IRB.CreateMul(I.getAlignmentCst(),
1352  ConstantInt::get(I.getAlignmentCst()->getType(),
1353  DFSF.DFS.ShadowWidth / 8));
1354  } else {
1355  AlignShadow = ConstantInt::get(I.getAlignmentCst()->getType(),
1356  DFSF.DFS.ShadowWidth / 8);
1357  }
1358  Type *Int8Ptr = Type::getInt8PtrTy(*DFSF.DFS.Ctx);
1359  DestShadow = IRB.CreateBitCast(DestShadow, Int8Ptr);
1360  SrcShadow = IRB.CreateBitCast(SrcShadow, Int8Ptr);
1361  IRB.CreateCall(I.getCalledValue(), {DestShadow, SrcShadow, LenShadow,
1362  AlignShadow, I.getVolatileCst()});
1363 }
1364 
1365 void DFSanVisitor::visitReturnInst(ReturnInst &RI) {
1366  if (!DFSF.IsNativeABI && RI.getReturnValue()) {
1367  switch (DFSF.IA) {
1368  case DataFlowSanitizer::IA_TLS: {
1369  Value *S = DFSF.getShadow(RI.getReturnValue());
1370  IRBuilder<> IRB(&RI);
1371  IRB.CreateStore(S, DFSF.getRetvalTLS());
1372  break;
1373  }
1374  case DataFlowSanitizer::IA_Args: {
1375  IRBuilder<> IRB(&RI);
1376  Type *RT = DFSF.F->getFunctionType()->getReturnType();
1377  Value *InsVal =
1378  IRB.CreateInsertValue(UndefValue::get(RT), RI.getReturnValue(), 0);
1379  Value *InsShadow =
1380  IRB.CreateInsertValue(InsVal, DFSF.getShadow(RI.getReturnValue()), 1);
1381  RI.setOperand(0, InsShadow);
1382  break;
1383  }
1384  }
1385  }
1386 }
1387 
1388 void DFSanVisitor::visitCallSite(CallSite CS) {
1389  Function *F = CS.getCalledFunction();
1390  if ((F && F->isIntrinsic()) || isa<InlineAsm>(CS.getCalledValue())) {
1391  visitOperandShadowInst(*CS.getInstruction());
1392  return;
1393  }
1394 
1395  // Calls to this function are synthesized in wrappers, and we shouldn't
1396  // instrument them.
1397  if (F == DFSF.DFS.DFSanVarargWrapperFn)
1398  return;
1399 
1400  assert(!(cast<FunctionType>(
1401  CS.getCalledValue()->getType()->getPointerElementType())->isVarArg() &&
1403 
1404  IRBuilder<> IRB(CS.getInstruction());
1405 
1407  DFSF.DFS.UnwrappedFnMap.find(CS.getCalledValue());
1408  if (i != DFSF.DFS.UnwrappedFnMap.end()) {
1409  Function *F = i->second;
1410  switch (DFSF.DFS.getWrapperKind(F)) {
1411  case DataFlowSanitizer::WK_Warning: {
1412  CS.setCalledFunction(F);
1413  IRB.CreateCall(DFSF.DFS.DFSanUnimplementedFn,
1414  IRB.CreateGlobalStringPtr(F->getName()));
1415  DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1416  return;
1417  }
1418  case DataFlowSanitizer::WK_Discard: {
1419  CS.setCalledFunction(F);
1420  DFSF.setShadow(CS.getInstruction(), DFSF.DFS.ZeroShadow);
1421  return;
1422  }
1423  case DataFlowSanitizer::WK_Functional: {
1424  CS.setCalledFunction(F);
1425  visitOperandShadowInst(*CS.getInstruction());
1426  return;
1427  }
1428  case DataFlowSanitizer::WK_Custom: {
1429  // Don't try to handle invokes of custom functions, it's too complicated.
1430  // Instead, invoke the dfsw$ wrapper, which will in turn call the __dfsw_
1431  // wrapper.
1432  if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) {
1433  FunctionType *FT = F->getFunctionType();
1434  FunctionType *CustomFT = DFSF.DFS.getCustomFunctionType(FT);
1435  std::string CustomFName = "__dfsw_";
1436  CustomFName += F->getName();
1437  Constant *CustomF =
1438  DFSF.DFS.Mod->getOrInsertFunction(CustomFName, CustomFT);
1439  if (Function *CustomFn = dyn_cast<Function>(CustomF)) {
1440  CustomFn->copyAttributesFrom(F);
1441 
1442  // Custom functions returning non-void will write to the return label.
1443  if (!FT->getReturnType()->isVoidTy()) {
1444  CustomFn->removeAttributes(AttributeSet::FunctionIndex,
1445  DFSF.DFS.ReadOnlyNoneAttrs);
1446  }
1447  }
1448 
1449  std::vector<Value *> Args;
1450 
1451  CallSite::arg_iterator i = CS.arg_begin();
1452  for (unsigned n = FT->getNumParams(); n != 0; ++i, --n) {
1453  Type *T = (*i)->getType();
1454  FunctionType *ParamFT;
1455  if (isa<PointerType>(T) &&
1456  (ParamFT = dyn_cast<FunctionType>(
1457  cast<PointerType>(T)->getElementType()))) {
1458  std::string TName = "dfst";
1459  TName += utostr(FT->getNumParams() - n);
1460  TName += "$";
1461  TName += F->getName();
1462  Constant *T = DFSF.DFS.getOrBuildTrampolineFunction(ParamFT, TName);
1463  Args.push_back(T);
1464  Args.push_back(
1465  IRB.CreateBitCast(*i, Type::getInt8PtrTy(*DFSF.DFS.Ctx)));
1466  } else {
1467  Args.push_back(*i);
1468  }
1469  }
1470 
1471  i = CS.arg_begin();
1472  for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1473  Args.push_back(DFSF.getShadow(*i));
1474 
1475  if (FT->isVarArg()) {
1476  auto *LabelVATy = ArrayType::get(DFSF.DFS.ShadowTy,
1477  CS.arg_size() - FT->getNumParams());
1478  auto *LabelVAAlloca = new AllocaInst(LabelVATy, "labelva",
1479  DFSF.F->getEntryBlock().begin());
1480 
1481  for (unsigned n = 0; i != CS.arg_end(); ++i, ++n) {
1482  auto LabelVAPtr = IRB.CreateStructGEP(LabelVATy, LabelVAAlloca, n);
1483  IRB.CreateStore(DFSF.getShadow(*i), LabelVAPtr);
1484  }
1485 
1486  Args.push_back(IRB.CreateStructGEP(LabelVATy, LabelVAAlloca, 0));
1487  }
1488 
1489  if (!FT->getReturnType()->isVoidTy()) {
1490  if (!DFSF.LabelReturnAlloca) {
1491  DFSF.LabelReturnAlloca =
1492  new AllocaInst(DFSF.DFS.ShadowTy, "labelreturn",
1493  DFSF.F->getEntryBlock().begin());
1494  }
1495  Args.push_back(DFSF.LabelReturnAlloca);
1496  }
1497 
1498  for (i = CS.arg_begin() + FT->getNumParams(); i != CS.arg_end(); ++i)
1499  Args.push_back(*i);
1500 
1501  CallInst *CustomCI = IRB.CreateCall(CustomF, Args);
1502  CustomCI->setCallingConv(CI->getCallingConv());
1503  CustomCI->setAttributes(CI->getAttributes());
1504 
1505  if (!FT->getReturnType()->isVoidTy()) {
1506  LoadInst *LabelLoad = IRB.CreateLoad(DFSF.LabelReturnAlloca);
1507  DFSF.setShadow(CustomCI, LabelLoad);
1508  }
1509 
1510  CI->replaceAllUsesWith(CustomCI);
1511  CI->eraseFromParent();
1512  return;
1513  }
1514  break;
1515  }
1516  }
1517  }
1518 
1519  FunctionType *FT = cast<FunctionType>(
1521  if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1522  for (unsigned i = 0, n = FT->getNumParams(); i != n; ++i) {
1523  IRB.CreateStore(DFSF.getShadow(CS.getArgument(i)),
1524  DFSF.getArgTLS(i, CS.getInstruction()));
1525  }
1526  }
1527 
1528  Instruction *Next = nullptr;
1529  if (!CS.getType()->isVoidTy()) {
1530  if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1531  if (II->getNormalDest()->getSinglePredecessor()) {
1532  Next = II->getNormalDest()->begin();
1533  } else {
1534  BasicBlock *NewBB =
1535  SplitEdge(II->getParent(), II->getNormalDest(), &DFSF.DT);
1536  Next = NewBB->begin();
1537  }
1538  } else {
1539  Next = CS->getNextNode();
1540  }
1541 
1542  if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_TLS) {
1543  IRBuilder<> NextIRB(Next);
1544  LoadInst *LI = NextIRB.CreateLoad(DFSF.getRetvalTLS());
1545  DFSF.SkipInsts.insert(LI);
1546  DFSF.setShadow(CS.getInstruction(), LI);
1547  DFSF.NonZeroChecks.push_back(LI);
1548  }
1549  }
1550 
1551  // Do all instrumentation for IA_Args down here to defer tampering with the
1552  // CFG in a way that SplitEdge may be able to detect.
1553  if (DFSF.DFS.getInstrumentedABI() == DataFlowSanitizer::IA_Args) {
1554  FunctionType *NewFT = DFSF.DFS.getArgsFunctionType(FT);
1555  Value *Func =
1556  IRB.CreateBitCast(CS.getCalledValue(), PointerType::getUnqual(NewFT));
1557  std::vector<Value *> Args;
1558 
1559  CallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
1560  for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1561  Args.push_back(*i);
1562 
1563  i = CS.arg_begin();
1564  for (unsigned n = FT->getNumParams(); n != 0; ++i, --n)
1565  Args.push_back(DFSF.getShadow(*i));
1566 
1567  if (FT->isVarArg()) {
1568  unsigned VarArgSize = CS.arg_size() - FT->getNumParams();
1569  ArrayType *VarArgArrayTy = ArrayType::get(DFSF.DFS.ShadowTy, VarArgSize);
1570  AllocaInst *VarArgShadow =
1571  new AllocaInst(VarArgArrayTy, "", DFSF.F->getEntryBlock().begin());
1572  Args.push_back(IRB.CreateConstGEP2_32(VarArgArrayTy, VarArgShadow, 0, 0));
1573  for (unsigned n = 0; i != e; ++i, ++n) {
1574  IRB.CreateStore(
1575  DFSF.getShadow(*i),
1576  IRB.CreateConstGEP2_32(VarArgArrayTy, VarArgShadow, 0, n));
1577  Args.push_back(*i);
1578  }
1579  }
1580 
1581  CallSite NewCS;
1582  if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
1583  NewCS = IRB.CreateInvoke(Func, II->getNormalDest(), II->getUnwindDest(),
1584  Args);
1585  } else {
1586  NewCS = IRB.CreateCall(Func, Args);
1587  }
1588  NewCS.setCallingConv(CS.getCallingConv());
1590  *DFSF.DFS.Ctx, AttributeSet::ReturnIndex,
1592 
1593  if (Next) {
1594  ExtractValueInst *ExVal =
1595  ExtractValueInst::Create(NewCS.getInstruction(), 0, "", Next);
1596  DFSF.SkipInsts.insert(ExVal);
1597  ExtractValueInst *ExShadow =
1598  ExtractValueInst::Create(NewCS.getInstruction(), 1, "", Next);
1599  DFSF.SkipInsts.insert(ExShadow);
1600  DFSF.setShadow(ExVal, ExShadow);
1601  DFSF.NonZeroChecks.push_back(ExShadow);
1602 
1603  CS.getInstruction()->replaceAllUsesWith(ExVal);
1604  }
1605 
1607  }
1608 }
1609 
1610 void DFSanVisitor::visitPHINode(PHINode &PN) {
1611  PHINode *ShadowPN =
1612  PHINode::Create(DFSF.DFS.ShadowTy, PN.getNumIncomingValues(), "", &PN);
1613 
1614  // Give the shadow phi node valid predecessors to fool SplitEdge into working.
1615  Value *UndefShadow = UndefValue::get(DFSF.DFS.ShadowTy);
1616  for (PHINode::block_iterator i = PN.block_begin(), e = PN.block_end(); i != e;
1617  ++i) {
1618  ShadowPN->addIncoming(UndefShadow, *i);
1619  }
1620 
1621  DFSF.PHIFixups.push_back(std::make_pair(&PN, ShadowPN));
1622  DFSF.setShadow(&PN, ShadowPN);
1623 }
const NoneType None
Definition: None.h:23
ReturnInst - Return a value (possibly void), from a function.
Value * getValueOperand()
Definition: Instructions.h:406
const Value * getCalledValue() const
getCalledValue - Get a pointer to the function that is invoked by this instruction.
iplist< Instruction >::iterator eraseFromParent()
eraseFromParent - This method unlinks 'this' from the containing basic block and deletes it...
Definition: Instruction.cpp:70
static cl::list< std::string > ClABIListFiles("dfsan-abilist", cl::desc("File listing native ABI functions and how the pass treats them"), cl::Hidden)
void push_back(const T &Elt)
Definition: SmallVector.h:222
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:104
LinkageTypes getLinkage() const
Definition: GlobalValue.h:289
IntegerType * getType() const
getType - Specialize the getType() method to always return an IntegerType, which reduces the amount o...
Definition: Constants.h:140
void ReplaceInstWithInst(BasicBlock::InstListType &BIL, BasicBlock::iterator &BI, Instruction *I)
ReplaceInstWithInst - Replace the instruction specified by BI with the instruction specified by I...
This class is the base class for the comparison instructions.
Definition: InstrTypes.h:679
void addIncoming(Value *V, BasicBlock *BB)
addIncoming - Add an incoming value to the end of the PHI list
ExtractValueInst - This instruction extracts a struct member or array element value from an aggregate...
LLVMContext & getContext() const
getContext - Return a reference to the LLVMContext associated with this function. ...
Definition: Function.cpp:223
LLVM Argument representation.
Definition: Argument.h:35
Base class for instruction visitors.
Definition: InstVisitor.h:81
ValTy * getArgument(unsigned ArgNo) const
Definition: CallSite.h:119
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:114
unsigned getNumParams() const
getNumParams - Return the number of fixed parameters this function type requires. ...
Definition: DerivedTypes.h:136
InstrTy * getInstruction() const
Definition: CallSite.h:82
ConstantInt * getAlignmentCst() const
Value * getValue() const
get* - Return the arguments to the instruction.
DenseSet - This implements a dense probed hash-table based set.
Definition: DenseSet.h:39
unsigned getNumOperands() const
Definition: User.h:138
Type::subtype_iterator param_iterator
Definition: DerivedTypes.h:123
CallInst - This class represents a function call, abstracting a target machine's calling convention...
bool isIntrinsic() const
Definition: Function.h:160
size_type count(PtrType Ptr) const
count - Return 1 if the specified pointer is in the set, 0 otherwise.
Definition: SmallPtrSet.h:276
TerminatorInst * SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore, bool Unreachable, MDNode *BranchWeights=nullptr, DominatorTree *DT=nullptr)
SplitBlockAndInsertIfThen - Split the containing block at the specified instruction - everything befo...
ShuffleVectorInst - This instruction constructs a fixed permutation of two input vectors.
MemSetInst - This class wraps the llvm.memset intrinsic.
void setAttributes(const AttributeSet &PAL)
Definition: CallSite.h:232
arg_iterator arg_end()
Definition: Function.h:480
const Instruction & front() const
Definition: BasicBlock.h:243
Metadata node.
Definition: Metadata.h:740
F(f)
LoadInst - an instruction for reading from memory.
Definition: Instructions.h:177
AttrBuilder & addAttribute(Attribute::AttrKind Val)
Add an attribute to the builder.
void GetUnderlyingObjects(Value *V, SmallVectorImpl< Value * > &Objects, const DataLayout &DL, LoopInfo *LI=nullptr, unsigned MaxLookup=6)
This method is similar to GetUnderlyingObject except that it can look through phi and select instruct...
const std::string & getTargetTriple() const
Get the target triple which is a string describing the target host.
Definition: Module.h:261
LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason, bool gen_crash_diag=true)
Reports a serious error, calling any installed error handler.
Type * getPointerElementType() const
Definition: Type.h:366
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:188
block_iterator block_end()
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:231
void setCallingConv(CallingConv::ID CC)
static cl::opt< bool > ClArgsABI("dfsan-args-abi", cl::desc("Use the argument ABI rather than the TLS ABI"), cl::Hidden)
IterTy arg_end() const
Definition: CallSite.h:157
BlockAddress - The address of a basic block.
Definition: Constants.h:802
SelectInst - This class represents the LLVM 'select' instruction.
Value * getReturnValue() const
Convenience accessor. Returns null if there is no return value.
This is the base class for all instructions that perform data casts.
Definition: InstrTypes.h:389
NodeTy * getNextNode()
Get the next node, or 0 for the list tail.
Definition: ilist_node.h:80
StructType - Class to represent struct types.
Definition: DerivedTypes.h:191
param_iterator param_end() const
Definition: DerivedTypes.h:125
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:517
void setThreadLocalMode(ThreadLocalMode Val)
Definition: GlobalValue.h:156
void setModuleInlineAsm(StringRef Asm)
Set the module-scope inline assembly blocks.
Definition: Module.h:298
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:250
const std::string & getModuleIdentifier() const
Get the module identifier which is, essentially, the name of the module.
Definition: Module.h:242
static cl::opt< bool > ClCombinePointerLabelsOnStore("dfsan-combine-pointer-labels-on-store", cl::desc("Combine the label of the pointer with the label of the data when ""storing in memory."), cl::Hidden, cl::init(false))
block_iterator block_begin()
#define G(x, y, z)
Definition: MD5.cpp:52
FunctionType - Class to represent function types.
Definition: DerivedTypes.h:96
ValTy * getCalledValue() const
getCalledValue - Return the pointer to function that is being called.
Definition: CallSite.h:91
ArrayType - Class to represent array types.
Definition: DerivedTypes.h:336
BasicBlock * getSuccessor(unsigned i) const
Base class for the actual dominator tree node.
static std::string utostr(uint64_t X, bool isNeg=false)
Definition: StringExtras.h:93
ArchType getArch() const
getArch - Get the parsed architecture type of this triple.
Definition: Triple.h:242
StoreInst - an instruction for storing to memory.
Definition: Instructions.h:316
void setCallingConv(CallingConv::ID CC)
Definition: CallSite.h:215
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:351
void removeAttributes(unsigned i, AttributeSet attr)
removes the attributes from the list of attributes.
Definition: Function.cpp:353
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:256
iterator begin()
Definition: Function.h:457
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:67
Type * getElementType() const
Definition: DerivedTypes.h:323
void addAttribute(unsigned i, Attribute::AttrKind attr)
addAttribute - adds the attribute to the list of attributes.
PointerType - Class to represent pointers.
Definition: DerivedTypes.h:449
unsigned getNumIncomingValues() const
getNumIncomingValues - Return the number of incoming edges
GetElementPtrInst - an instruction for type-safe pointer arithmetic to access elements of arrays and ...
Definition: Instructions.h:830
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:325
InsertElementInst - This instruction inserts a single (scalar) element into a VectorType value...
unsigned getAlignment() const
getAlignment - Return the alignment of the access that is being performed
Definition: Instructions.h:365
alias_iterator alias_end()
Definition: Module.h:593
LLVM Basic Block Representation.
Definition: BasicBlock.h:65
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:41
BranchInst - Conditional or Unconditional Branch instruction.
FunTy * getCalledFunction() const
getCalledFunction - Return the function being called if this is a direct call, otherwise return null ...
Definition: CallSite.h:99
size_type LLVM_ATTRIBUTE_UNUSED_RESULT size() const
Definition: ilist.h:539
UnreachableInst - This function has undefined behavior.
This is an important base class in LLVM.
Definition: Constant.h:41
const Value * getCondition() const
param_iterator param_begin() const
Definition: DerivedTypes.h:124
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:264
ConstantInt * getVolatileCst() const
size_t size() const
Definition: Function.h:462
void copyAttributesFrom(const GlobalValue *Src) override
copyAttributesFrom - copy all additional attributes (those not needed to create a Function) from the ...
Definition: Function.cpp:416
Value * getOperand(unsigned i) const
Definition: User.h:118
Value * getPointerOperand()
Definition: Instructions.h:284
arg_iterator arg_begin()
Definition: Function.h:472
Class to represent integer types.
Definition: DerivedTypes.h:37
void setAlignment(unsigned Align)
void append(in_iter in_start, in_iter in_end)
Add the specified range to the end of the SmallVector.
Definition: SmallVector.h:416
CallInst * CreateCall(Value *Callee, ArrayRef< Value * > Args=None, const Twine &Name="")
Definition: IRBuilder.h:1467
PointerType * getPointerTo(unsigned AddrSpace=0)
getPointerTo - Return a pointer to the current type.
Definition: Type.cpp:764
MDNode * createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight)
Return metadata containing two branch weights.
Definition: MDBuilder.cpp:37
const Value * getTrueValue() const
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
void setSuccessor(unsigned idx, BasicBlock *NewSucc)
const std::string & getModuleInlineAsm() const
Get any module-scope inline assembly blocks.
Definition: Module.h:269
IntegerType * getIntPtrType(LLVMContext &C, unsigned AddressSpace=0) const
Returns an integer type with size at least as big as that of a pointer in the given address space...
Definition: DataLayout.cpp:694
unsigned getABITypeAlignment(Type *Ty) const
Returns the minimum ABI-required alignment for the specified type.
Definition: DataLayout.cpp:674
const BasicBlockListType & getBasicBlockList() const
Definition: Function.h:436
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:299
This is the shared class of boolean and integer constants.
Definition: Constants.h:47
Value * getDest() const
getDest - This is just like getRawDest, but it strips off any cast instructions that feed it...
const Module * getModule() const
Return the module owning the function this instruction belongs to or nullptr it the function does not...
Definition: Instruction.cpp:57
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:861
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:222
static cl::opt< bool > ClDebugNonzeroLabels("dfsan-debug-nonzero-labels", cl::desc("Insert calls to __dfsan_nonzero_label on observing a parameter, ""load or return with a nonzero label"), cl::Hidden)
Value * getLength() const
alias_iterator alias_begin()
Definition: Module.h:591
unsigned arg_size() const
Definition: CallSite.h:162
BasicBlock * getBasicBlock() const
Definition: Constants.h:829
const BasicBlock & getEntryBlock() const
Definition: Function.h:442
static cl::opt< AlignMode > Align(cl::desc("Load/store alignment support"), cl::Hidden, cl::init(NoStrictAlign), cl::values(clEnumValN(StrictAlign,"aarch64-strict-align","Disallow all unaligned memory accesses"), clEnumValN(NoStrictAlign,"aarch64-no-strict-align","Allow unaligned memory accesses"), clEnumValEnd))
void setLinkage(LinkageTypes LT)
Definition: GlobalValue.h:284
void splice(iterator where, iplist &L2)
Definition: ilist.h:570
void setOperand(unsigned i, Value *Val)
Definition: User.h:122
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:576
static cl::opt< bool > ClPreserveAlignment("dfsan-preserve-alignment", cl::desc("respect alignment requirements provided by input IR"), cl::Hidden, cl::init(false))
AttributeSet removeAttributes(LLVMContext &C, unsigned Index, AttributeSet Attrs) const
Remove the specified attributes at the specified index from this attribute list.
Definition: Attributes.cpp:828
VectorType - Class to represent vector types.
Definition: DerivedTypes.h:362
void eraseFromParent() override
eraseFromParent - This method unlinks 'this' from the containing module and deletes it...
Definition: Globals.cpp:277
LinkageTypes
An enumeration for the kinds of linkage for global values.
Definition: GlobalValue.h:39
INITIALIZE_PASS(DataFlowSanitizer,"dfsan","DataFlowSanitizer: dynamic data flow analysis.", false, false) ModulePass *llvm
void addAttribute(unsigned i, Attribute::AttrKind attr)
adds the attribute to the list of attributes.
Definition: Function.cpp:341
iterator_range< user_iterator > users()
Definition: Value.h:300
LLVM_ATTRIBUTE_UNUSED_RESULT std::enable_if< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:285
void eraseFromParent() override
eraseFromParent - This method unlinks 'this' from the containing module and deletes it...
Definition: Function.cpp:241
const AttributeSet & getAttributes() const
getAttributes - Return the parameter attributes for this call.
reference front()
Definition: ilist.h:390
Value * getSource() const
getSource - This is just like getRawSource, but it strips off any cast instructions that feed it...
PointerType * getType() const
Global values are always pointers.
Definition: GlobalValue.h:185
MemTransferInst - This class wraps the llvm.memcpy/memmove intrinsics.
const DataLayout & getDataLayout() const
Get the data layout for the module's target platform.
Definition: Module.cpp:372
iterator end()
Definition: Module.h:571
bool isDeclaration() const
Return true if the primary definition of this global value is outside of the current translation unit...
Definition: Globals.cpp:128
void setCalledFunction(Value *V)
setCalledFunction - Set the callee to the specified value.
Definition: CallSite.h:105
unsigned getAlignment() const
getAlignment - Return the alignment of the access that is being performed
Definition: Instructions.h:243
AttrBuilder typeIncompatible(const Type *Ty)
Which attributes cannot be applied to a type.
CallingConv::ID getCallingConv() const
getCallingConv/setCallingConv - get or set the calling convention of the call.
Definition: CallSite.h:212
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
TerminatorInst * getTerminator()
Returns the terminator instruction if the block is well formed or null if the block is not well forme...
Definition: BasicBlock.cpp:124
FunctionType * getFunctionType() const
Definition: Function.cpp:227
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:236
iterator begin()
Definition: Module.h:569
const AttributeSet & getAttributes() const
getAttributes/setAttributes - get or set the parameter attributes of the call.
Definition: CallSite.h:229
ExtractElementInst - This instruction extracts a single (scalar) element from a VectorType value...
BasicBlock * splitBasicBlock(iterator I, const Twine &BBName="")
Split the basic block into two basic blocks at the specified instruction.
Definition: BasicBlock.cpp:348
uint64_t getTypeStoreSize(Type *Ty) const
Returns the maximum number of bytes that may be overwritten by storing the specified type...
Definition: DataLayout.h:371
reference back()
Definition: ilist.h:398
bool isVarArg() const
Definition: DerivedTypes.h:120
Type * getType() const
getType - Return the type of the instruction that generated this call site
Definition: CallSite.h:166
iterator_range< df_iterator< T > > depth_first(const T &G)
void setAttributes(const AttributeSet &Attrs)
setAttributes - Set the parameter attributes for this call.
Type * getReturnType() const
Definition: DerivedTypes.h:121
const GlobalObject * getBaseObject() const
Definition: GlobalAlias.h:88
user_iterator user_begin()
Definition: Value.h:294
DenseMap< const Function *, DISubprogram * > makeSubprogramMap(const Module &M)
Definition: DebugInfo.cpp:377
aarch64 promote const
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:365
LLVM Value Representation.
Definition: Value.h:69
const ArgumentListType & getArgumentList() const
Get the underlying elements of the Function...
Definition: Function.h:424
ModulePass * createDataFlowSanitizerPass(const std::vector< std::string > &ABIListFiles=std::vector< std::string >(), void *(*getArgTLS)()=nullptr, void *(*getRetValTLS)()=nullptr)
InvokeInst - Invoke instruction.
BasicBlock * SplitEdge(BasicBlock *From, BasicBlock *To, DominatorTree *DT=nullptr, LoopInfo *LI=nullptr)
SplitEdge - Split the edge connecting specified block.
IterTy arg_begin() const
arg_begin/arg_end - Return iterators corresponding to the actual argument list for a call site...
Definition: CallSite.h:151
C - The default llvm calling convention, compatible with C.
Definition: CallingConv.h:34
const Value * getFalseValue() const
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:40
bool removeUnreachableBlocks(Function &F)
Remove all blocks that can not be reached from the function's entry.
Definition: Local.cpp:1254
CallingConv::ID getCallingConv() const
getCallingConv/setCallingConv - Get or set the calling convention of this function call...
static cl::opt< bool > ClCombinePointerLabelsOnLoad("dfsan-combine-pointer-labels-on-load", cl::desc("Combine the label of the pointer with the label of the data when ""loading from memory."), cl::Hidden, cl::init(true))
bool isVarArg() const
isVarArg - Return true if this function takes a variable number of arguments.
Definition: Function.cpp:229
Value * getPointerOperand()
Definition: Instructions.h:409
const BasicBlock * getParent() const
Definition: Instruction.h:72
LLVMContext & getContext() const
Get the global data context.
Definition: Module.h:265
bool isVoidTy() const
isVoidTy - Return true if this is 'void'.
Definition: Type.h:137
AllocaInst - an instruction to allocate memory on the stack.
Definition: Instructions.h:76
InsertValueInst - This instruction inserts a struct field of array element value into an aggregate va...
user_iterator user_end()
Definition: Value.h:296