diff options
| author | Dimitry Andric <dim@FreeBSD.org> | 2019-01-20 11:41:25 +0000 | 
|---|---|---|
| committer | Dimitry Andric <dim@FreeBSD.org> | 2019-01-20 11:41:25 +0000 | 
| commit | d9484dd61cc151c4f34c31e07f693fefa66316b5 (patch) | |
| tree | ab0560b3da293f1fafd3269c59692e929418f5c2 /contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp | |
| parent | 79e0962d4c3cf1f0acf359a9d69cb3ac68c414c4 (diff) | |
| parent | d8e91e46262bc44006913e6796843909f1ac7bcd (diff) | |
Notes
Diffstat (limited to 'contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp | 673 | 
1 files changed, 673 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp b/contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp new file mode 100644 index 000000000000..66b03845864f --- /dev/null +++ b/contrib/llvm/lib/Analysis/StackSafetyAnalysis.cpp @@ -0,0 +1,673 @@ +//===- StackSafetyAnalysis.cpp - Stack memory safety analysis -------------===// +// +//                     The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +//===----------------------------------------------------------------------===// + +#include "llvm/Analysis/StackSafetyAnalysis.h" +#include "llvm/Analysis/ScalarEvolutionExpressions.h" +#include "llvm/IR/CallSite.h" +#include "llvm/IR/InstIterator.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/Support/raw_ostream.h" + +using namespace llvm; + +#define DEBUG_TYPE "stack-safety" + +static cl::opt<int> StackSafetyMaxIterations("stack-safety-max-iterations", +                                             cl::init(20), cl::Hidden); + +namespace { + +/// Rewrite an SCEV expression for a memory access address to an expression that +/// represents offset from the given alloca. +class AllocaOffsetRewriter : public SCEVRewriteVisitor<AllocaOffsetRewriter> { +  const Value *AllocaPtr; + +public: +  AllocaOffsetRewriter(ScalarEvolution &SE, const Value *AllocaPtr) +      : SCEVRewriteVisitor(SE), AllocaPtr(AllocaPtr) {} + +  const SCEV *visit(const SCEV *Expr) { +    // Only re-write the expression if the alloca is used in an addition +    // expression (it can be used in other types of expressions if it's cast to +    // an int and passed as an argument.) +    if (!isa<SCEVAddRecExpr>(Expr) && !isa<SCEVAddExpr>(Expr) && +        !isa<SCEVUnknown>(Expr)) +      return Expr; +    return SCEVRewriteVisitor<AllocaOffsetRewriter>::visit(Expr); +  } + +  const SCEV *visitUnknown(const SCEVUnknown *Expr) { +    // FIXME: look through one or several levels of definitions? +    // This can be inttoptr(AllocaPtr) and SCEV would not unwrap +    // it for us. +    if (Expr->getValue() == AllocaPtr) +      return SE.getZero(Expr->getType()); +    return Expr; +  } +}; + +/// Describes use of address in as a function call argument. +struct PassAsArgInfo { +  /// Function being called. +  const GlobalValue *Callee = nullptr; +  /// Index of argument which pass address. +  size_t ParamNo = 0; +  // Offset range of address from base address (alloca or calling function +  // argument). +  // Range should never set to empty-set, that is an invalid access range +  // that can cause empty-set to be propagated with ConstantRange::add +  ConstantRange Offset; +  PassAsArgInfo(const GlobalValue *Callee, size_t ParamNo, ConstantRange Offset) +      : Callee(Callee), ParamNo(ParamNo), Offset(Offset) {} + +  StringRef getName() const { return Callee->getName(); } +}; + +raw_ostream &operator<<(raw_ostream &OS, const PassAsArgInfo &P) { +  return OS << "@" << P.getName() << "(arg" << P.ParamNo << ", " << P.Offset +            << ")"; +} + +/// Describe uses of address (alloca or parameter) inside of the function. +struct UseInfo { +  // Access range if the address (alloca or parameters). +  // It is allowed to be empty-set when there are no known accesses. +  ConstantRange Range; + +  // List of calls which pass address as an argument. +  SmallVector<PassAsArgInfo, 4> Calls; + +  explicit UseInfo(unsigned PointerSize) : Range{PointerSize, false} {} + +  void updateRange(ConstantRange R) { Range = Range.unionWith(R); } +}; + +raw_ostream &operator<<(raw_ostream &OS, const UseInfo &U) { +  OS << U.Range; +  for (auto &Call : U.Calls) +    OS << ", " << Call; +  return OS; +} + +struct AllocaInfo { +  const AllocaInst *AI = nullptr; +  uint64_t Size = 0; +  UseInfo Use; + +  AllocaInfo(unsigned PointerSize, const AllocaInst *AI, uint64_t Size) +      : AI(AI), Size(Size), Use(PointerSize) {} + +  StringRef getName() const { return AI->getName(); } +}; + +raw_ostream &operator<<(raw_ostream &OS, const AllocaInfo &A) { +  return OS << A.getName() << "[" << A.Size << "]: " << A.Use; +} + +struct ParamInfo { +  const Argument *Arg = nullptr; +  UseInfo Use; + +  explicit ParamInfo(unsigned PointerSize, const Argument *Arg) +      : Arg(Arg), Use(PointerSize) {} + +  StringRef getName() const { return Arg ? Arg->getName() : "<N/A>"; } +}; + +raw_ostream &operator<<(raw_ostream &OS, const ParamInfo &P) { +  return OS << P.getName() << "[]: " << P.Use; +} + +/// Calculate the allocation size of a given alloca. Returns 0 if the +/// size can not be statically determined. +uint64_t getStaticAllocaAllocationSize(const AllocaInst *AI) { +  const DataLayout &DL = AI->getModule()->getDataLayout(); +  uint64_t Size = DL.getTypeAllocSize(AI->getAllocatedType()); +  if (AI->isArrayAllocation()) { +    auto C = dyn_cast<ConstantInt>(AI->getArraySize()); +    if (!C) +      return 0; +    Size *= C->getZExtValue(); +  } +  return Size; +} + +} // end anonymous namespace + +/// Describes uses of allocas and parameters inside of a single function. +struct StackSafetyInfo::FunctionInfo { +  // May be a Function or a GlobalAlias +  const GlobalValue *GV = nullptr; +  // Informations about allocas uses. +  SmallVector<AllocaInfo, 4> Allocas; +  // Informations about parameters uses. +  SmallVector<ParamInfo, 4> Params; +  // TODO: describe return value as depending on one or more of its arguments. + +  // StackSafetyDataFlowAnalysis counter stored here for faster access. +  int UpdateCount = 0; + +  FunctionInfo(const StackSafetyInfo &SSI) : FunctionInfo(*SSI.Info) {} + +  explicit FunctionInfo(const Function *F) : GV(F){}; +  // Creates FunctionInfo that forwards all the parameters to the aliasee. +  explicit FunctionInfo(const GlobalAlias *A); + +  FunctionInfo(FunctionInfo &&) = default; + +  bool IsDSOLocal() const { return GV->isDSOLocal(); }; + +  bool IsInterposable() const { return GV->isInterposable(); }; + +  StringRef getName() const { return GV->getName(); } + +  void print(raw_ostream &O) const { +    // TODO: Consider different printout format after +    // StackSafetyDataFlowAnalysis. Calls and parameters are irrelevant then. +    O << "  @" << getName() << (IsDSOLocal() ? "" : " dso_preemptable") +      << (IsInterposable() ? " interposable" : "") << "\n"; +    O << "    args uses:\n"; +    for (auto &P : Params) +      O << "      " << P << "\n"; +    O << "    allocas uses:\n"; +    for (auto &AS : Allocas) +      O << "      " << AS << "\n"; +  } + +private: +  FunctionInfo(const FunctionInfo &) = default; +}; + +StackSafetyInfo::FunctionInfo::FunctionInfo(const GlobalAlias *A) : GV(A) { +  unsigned PointerSize = A->getParent()->getDataLayout().getPointerSizeInBits(); +  const GlobalObject *Aliasee = A->getBaseObject(); +  const FunctionType *Type = cast<FunctionType>(Aliasee->getValueType()); +  // 'Forward' all parameters to this alias to the aliasee +  for (unsigned ArgNo = 0; ArgNo < Type->getNumParams(); ArgNo++) { +    Params.emplace_back(PointerSize, nullptr); +    UseInfo &US = Params.back().Use; +    US.Calls.emplace_back(Aliasee, ArgNo, ConstantRange(APInt(PointerSize, 0))); +  } +} + +namespace { + +class StackSafetyLocalAnalysis { +  const Function &F; +  const DataLayout &DL; +  ScalarEvolution &SE; +  unsigned PointerSize = 0; + +  const ConstantRange UnknownRange; + +  ConstantRange offsetFromAlloca(Value *Addr, const Value *AllocaPtr); +  ConstantRange getAccessRange(Value *Addr, const Value *AllocaPtr, +                               uint64_t AccessSize); +  ConstantRange getMemIntrinsicAccessRange(const MemIntrinsic *MI, const Use &U, +                                           const Value *AllocaPtr); + +  bool analyzeAllUses(const Value *Ptr, UseInfo &AS); + +  ConstantRange getRange(uint64_t Lower, uint64_t Upper) const { +    return ConstantRange(APInt(PointerSize, Lower), APInt(PointerSize, Upper)); +  } + +public: +  StackSafetyLocalAnalysis(const Function &F, ScalarEvolution &SE) +      : F(F), DL(F.getParent()->getDataLayout()), SE(SE), +        PointerSize(DL.getPointerSizeInBits()), +        UnknownRange(PointerSize, true) {} + +  // Run the transformation on the associated function. +  StackSafetyInfo run(); +}; + +ConstantRange +StackSafetyLocalAnalysis::offsetFromAlloca(Value *Addr, +                                           const Value *AllocaPtr) { +  if (!SE.isSCEVable(Addr->getType())) +    return UnknownRange; + +  AllocaOffsetRewriter Rewriter(SE, AllocaPtr); +  const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr)); +  ConstantRange Offset = SE.getUnsignedRange(Expr).zextOrTrunc(PointerSize); +  assert(!Offset.isEmptySet()); +  return Offset; +} + +ConstantRange StackSafetyLocalAnalysis::getAccessRange(Value *Addr, +                                                       const Value *AllocaPtr, +                                                       uint64_t AccessSize) { +  if (!SE.isSCEVable(Addr->getType())) +    return UnknownRange; + +  AllocaOffsetRewriter Rewriter(SE, AllocaPtr); +  const SCEV *Expr = Rewriter.visit(SE.getSCEV(Addr)); + +  ConstantRange AccessStartRange = +      SE.getUnsignedRange(Expr).zextOrTrunc(PointerSize); +  ConstantRange SizeRange = getRange(0, AccessSize); +  ConstantRange AccessRange = AccessStartRange.add(SizeRange); +  assert(!AccessRange.isEmptySet()); +  return AccessRange; +} + +ConstantRange StackSafetyLocalAnalysis::getMemIntrinsicAccessRange( +    const MemIntrinsic *MI, const Use &U, const Value *AllocaPtr) { +  if (auto MTI = dyn_cast<MemTransferInst>(MI)) { +    if (MTI->getRawSource() != U && MTI->getRawDest() != U) +      return getRange(0, 1); +  } else { +    if (MI->getRawDest() != U) +      return getRange(0, 1); +  } +  const auto *Len = dyn_cast<ConstantInt>(MI->getLength()); +  // Non-constant size => unsafe. FIXME: try SCEV getRange. +  if (!Len) +    return UnknownRange; +  ConstantRange AccessRange = getAccessRange(U, AllocaPtr, Len->getZExtValue()); +  return AccessRange; +} + +/// The function analyzes all local uses of Ptr (alloca or argument) and +/// calculates local access range and all function calls where it was used. +bool StackSafetyLocalAnalysis::analyzeAllUses(const Value *Ptr, UseInfo &US) { +  SmallPtrSet<const Value *, 16> Visited; +  SmallVector<const Value *, 8> WorkList; +  WorkList.push_back(Ptr); + +  // A DFS search through all uses of the alloca in bitcasts/PHI/GEPs/etc. +  while (!WorkList.empty()) { +    const Value *V = WorkList.pop_back_val(); +    for (const Use &UI : V->uses()) { +      auto I = cast<const Instruction>(UI.getUser()); +      assert(V == UI.get()); + +      switch (I->getOpcode()) { +      case Instruction::Load: { +        US.updateRange( +            getAccessRange(UI, Ptr, DL.getTypeStoreSize(I->getType()))); +        break; +      } + +      case Instruction::VAArg: +        // "va-arg" from a pointer is safe. +        break; +      case Instruction::Store: { +        if (V == I->getOperand(0)) { +          // Stored the pointer - conservatively assume it may be unsafe. +          US.updateRange(UnknownRange); +          return false; +        } +        US.updateRange(getAccessRange( +            UI, Ptr, DL.getTypeStoreSize(I->getOperand(0)->getType()))); +        break; +      } + +      case Instruction::Ret: +        // Information leak. +        // FIXME: Process parameters correctly. This is a leak only if we return +        // alloca. +        US.updateRange(UnknownRange); +        return false; + +      case Instruction::Call: +      case Instruction::Invoke: { +        ImmutableCallSite CS(I); + +        if (I->isLifetimeStartOrEnd()) +          break; + +        if (const MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I)) { +          US.updateRange(getMemIntrinsicAccessRange(MI, UI, Ptr)); +          break; +        } + +        // FIXME: consult devirt? +        // Do not follow aliases, otherwise we could inadvertently follow +        // dso_preemptable aliases or aliases with interposable linkage. +        const GlobalValue *Callee = dyn_cast<GlobalValue>( +            CS.getCalledValue()->stripPointerCastsNoFollowAliases()); +        if (!Callee) { +          US.updateRange(UnknownRange); +          return false; +        } + +        assert(isa<Function>(Callee) || isa<GlobalAlias>(Callee)); + +        ImmutableCallSite::arg_iterator B = CS.arg_begin(), E = CS.arg_end(); +        for (ImmutableCallSite::arg_iterator A = B; A != E; ++A) { +          if (A->get() == V) { +            ConstantRange Offset = offsetFromAlloca(UI, Ptr); +            US.Calls.emplace_back(Callee, A - B, Offset); +          } +        } + +        break; +      } + +      default: +        if (Visited.insert(I).second) +          WorkList.push_back(cast<const Instruction>(I)); +      } +    } +  } + +  return true; +} + +StackSafetyInfo StackSafetyLocalAnalysis::run() { +  StackSafetyInfo::FunctionInfo Info(&F); +  assert(!F.isDeclaration() && +         "Can't run StackSafety on a function declaration"); + +  LLVM_DEBUG(dbgs() << "[StackSafety] " << F.getName() << "\n"); + +  for (auto &I : instructions(F)) { +    if (auto AI = dyn_cast<AllocaInst>(&I)) { +      Info.Allocas.emplace_back(PointerSize, AI, +                                getStaticAllocaAllocationSize(AI)); +      AllocaInfo &AS = Info.Allocas.back(); +      analyzeAllUses(AI, AS.Use); +    } +  } + +  for (const Argument &A : make_range(F.arg_begin(), F.arg_end())) { +    Info.Params.emplace_back(PointerSize, &A); +    ParamInfo &PS = Info.Params.back(); +    analyzeAllUses(&A, PS.Use); +  } + +  LLVM_DEBUG(dbgs() << "[StackSafety] done\n"); +  LLVM_DEBUG(Info.print(dbgs())); +  return StackSafetyInfo(std::move(Info)); +} + +class StackSafetyDataFlowAnalysis { +  using FunctionMap = +      std::map<const GlobalValue *, StackSafetyInfo::FunctionInfo>; + +  FunctionMap Functions; +  // Callee-to-Caller multimap. +  DenseMap<const GlobalValue *, SmallVector<const GlobalValue *, 4>> Callers; +  SetVector<const GlobalValue *> WorkList; + +  unsigned PointerSize = 0; +  const ConstantRange UnknownRange; + +  ConstantRange getArgumentAccessRange(const GlobalValue *Callee, +                                       unsigned ParamNo) const; +  bool updateOneUse(UseInfo &US, bool UpdateToFullSet); +  void updateOneNode(const GlobalValue *Callee, +                     StackSafetyInfo::FunctionInfo &FS); +  void updateOneNode(const GlobalValue *Callee) { +    updateOneNode(Callee, Functions.find(Callee)->second); +  } +  void updateAllNodes() { +    for (auto &F : Functions) +      updateOneNode(F.first, F.second); +  } +  void runDataFlow(); +  void verifyFixedPoint(); + +public: +  StackSafetyDataFlowAnalysis( +      Module &M, std::function<const StackSafetyInfo &(Function &)> FI); +  StackSafetyGlobalInfo run(); +}; + +StackSafetyDataFlowAnalysis::StackSafetyDataFlowAnalysis( +    Module &M, std::function<const StackSafetyInfo &(Function &)> FI) +    : PointerSize(M.getDataLayout().getPointerSizeInBits()), +      UnknownRange(PointerSize, true) { +  // Without ThinLTO, run the local analysis for every function in the TU and +  // then run the DFA. +  for (auto &F : M.functions()) +    if (!F.isDeclaration()) +      Functions.emplace(&F, FI(F)); +  for (auto &A : M.aliases()) +    if (isa<Function>(A.getBaseObject())) +      Functions.emplace(&A, StackSafetyInfo::FunctionInfo(&A)); +} + +ConstantRange +StackSafetyDataFlowAnalysis::getArgumentAccessRange(const GlobalValue *Callee, +                                                    unsigned ParamNo) const { +  auto IT = Functions.find(Callee); +  // Unknown callee (outside of LTO domain or an indirect call). +  if (IT == Functions.end()) +    return UnknownRange; +  const StackSafetyInfo::FunctionInfo &FS = IT->second; +  // The definition of this symbol may not be the definition in this linkage +  // unit. +  if (!FS.IsDSOLocal() || FS.IsInterposable()) +    return UnknownRange; +  if (ParamNo >= FS.Params.size()) // possibly vararg +    return UnknownRange; +  return FS.Params[ParamNo].Use.Range; +} + +bool StackSafetyDataFlowAnalysis::updateOneUse(UseInfo &US, +                                               bool UpdateToFullSet) { +  bool Changed = false; +  for (auto &CS : US.Calls) { +    assert(!CS.Offset.isEmptySet() && +           "Param range can't be empty-set, invalid offset range"); + +    ConstantRange CalleeRange = getArgumentAccessRange(CS.Callee, CS.ParamNo); +    CalleeRange = CalleeRange.add(CS.Offset); +    if (!US.Range.contains(CalleeRange)) { +      Changed = true; +      if (UpdateToFullSet) +        US.Range = UnknownRange; +      else +        US.Range = US.Range.unionWith(CalleeRange); +    } +  } +  return Changed; +} + +void StackSafetyDataFlowAnalysis::updateOneNode( +    const GlobalValue *Callee, StackSafetyInfo::FunctionInfo &FS) { +  bool UpdateToFullSet = FS.UpdateCount > StackSafetyMaxIterations; +  bool Changed = false; +  for (auto &AS : FS.Allocas) +    Changed |= updateOneUse(AS.Use, UpdateToFullSet); +  for (auto &PS : FS.Params) +    Changed |= updateOneUse(PS.Use, UpdateToFullSet); + +  if (Changed) { +    LLVM_DEBUG(dbgs() << "=== update [" << FS.UpdateCount +                      << (UpdateToFullSet ? ", full-set" : "") << "] " +                      << FS.getName() << "\n"); +    // Callers of this function may need updating. +    for (auto &CallerID : Callers[Callee]) +      WorkList.insert(CallerID); + +    ++FS.UpdateCount; +  } +} + +void StackSafetyDataFlowAnalysis::runDataFlow() { +  Callers.clear(); +  WorkList.clear(); + +  SmallVector<const GlobalValue *, 16> Callees; +  for (auto &F : Functions) { +    Callees.clear(); +    StackSafetyInfo::FunctionInfo &FS = F.second; +    for (auto &AS : FS.Allocas) +      for (auto &CS : AS.Use.Calls) +        Callees.push_back(CS.Callee); +    for (auto &PS : FS.Params) +      for (auto &CS : PS.Use.Calls) +        Callees.push_back(CS.Callee); + +    llvm::sort(Callees); +    Callees.erase(std::unique(Callees.begin(), Callees.end()), Callees.end()); + +    for (auto &Callee : Callees) +      Callers[Callee].push_back(F.first); +  } + +  updateAllNodes(); + +  while (!WorkList.empty()) { +    const GlobalValue *Callee = WorkList.back(); +    WorkList.pop_back(); +    updateOneNode(Callee); +  } +} + +void StackSafetyDataFlowAnalysis::verifyFixedPoint() { +  WorkList.clear(); +  updateAllNodes(); +  assert(WorkList.empty()); +} + +StackSafetyGlobalInfo StackSafetyDataFlowAnalysis::run() { +  runDataFlow(); +  LLVM_DEBUG(verifyFixedPoint()); + +  StackSafetyGlobalInfo SSI; +  for (auto &F : Functions) +    SSI.emplace(F.first, std::move(F.second)); +  return SSI; +} + +void print(const StackSafetyGlobalInfo &SSI, raw_ostream &O, const Module &M) { +  size_t Count = 0; +  for (auto &F : M.functions()) +    if (!F.isDeclaration()) { +      SSI.find(&F)->second.print(O); +      O << "\n"; +      ++Count; +    } +  for (auto &A : M.aliases()) { +    SSI.find(&A)->second.print(O); +    O << "\n"; +    ++Count; +  } +  assert(Count == SSI.size() && "Unexpected functions in the result"); +} + +} // end anonymous namespace + +StackSafetyInfo::StackSafetyInfo() = default; +StackSafetyInfo::StackSafetyInfo(StackSafetyInfo &&) = default; +StackSafetyInfo &StackSafetyInfo::operator=(StackSafetyInfo &&) = default; + +StackSafetyInfo::StackSafetyInfo(FunctionInfo &&Info) +    : Info(new FunctionInfo(std::move(Info))) {} + +StackSafetyInfo::~StackSafetyInfo() = default; + +void StackSafetyInfo::print(raw_ostream &O) const { Info->print(O); } + +AnalysisKey StackSafetyAnalysis::Key; + +StackSafetyInfo StackSafetyAnalysis::run(Function &F, +                                         FunctionAnalysisManager &AM) { +  StackSafetyLocalAnalysis SSLA(F, AM.getResult<ScalarEvolutionAnalysis>(F)); +  return SSLA.run(); +} + +PreservedAnalyses StackSafetyPrinterPass::run(Function &F, +                                              FunctionAnalysisManager &AM) { +  OS << "'Stack Safety Local Analysis' for function '" << F.getName() << "'\n"; +  AM.getResult<StackSafetyAnalysis>(F).print(OS); +  return PreservedAnalyses::all(); +} + +char StackSafetyInfoWrapperPass::ID = 0; + +StackSafetyInfoWrapperPass::StackSafetyInfoWrapperPass() : FunctionPass(ID) { +  initializeStackSafetyInfoWrapperPassPass(*PassRegistry::getPassRegistry()); +} + +void StackSafetyInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { +  AU.addRequired<ScalarEvolutionWrapperPass>(); +  AU.setPreservesAll(); +} + +void StackSafetyInfoWrapperPass::print(raw_ostream &O, const Module *M) const { +  SSI.print(O); +} + +bool StackSafetyInfoWrapperPass::runOnFunction(Function &F) { +  StackSafetyLocalAnalysis SSLA( +      F, getAnalysis<ScalarEvolutionWrapperPass>().getSE()); +  SSI = StackSafetyInfo(SSLA.run()); +  return false; +} + +AnalysisKey StackSafetyGlobalAnalysis::Key; + +StackSafetyGlobalInfo +StackSafetyGlobalAnalysis::run(Module &M, ModuleAnalysisManager &AM) { +  FunctionAnalysisManager &FAM = +      AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); + +  StackSafetyDataFlowAnalysis SSDFA( +      M, [&FAM](Function &F) -> const StackSafetyInfo & { +        return FAM.getResult<StackSafetyAnalysis>(F); +      }); +  return SSDFA.run(); +} + +PreservedAnalyses StackSafetyGlobalPrinterPass::run(Module &M, +                                                    ModuleAnalysisManager &AM) { +  OS << "'Stack Safety Analysis' for module '" << M.getName() << "'\n"; +  print(AM.getResult<StackSafetyGlobalAnalysis>(M), OS, M); +  return PreservedAnalyses::all(); +} + +char StackSafetyGlobalInfoWrapperPass::ID = 0; + +StackSafetyGlobalInfoWrapperPass::StackSafetyGlobalInfoWrapperPass() +    : ModulePass(ID) { +  initializeStackSafetyGlobalInfoWrapperPassPass( +      *PassRegistry::getPassRegistry()); +} + +void StackSafetyGlobalInfoWrapperPass::print(raw_ostream &O, +                                             const Module *M) const { +  ::print(SSI, O, *M); +} + +void StackSafetyGlobalInfoWrapperPass::getAnalysisUsage( +    AnalysisUsage &AU) const { +  AU.addRequired<StackSafetyInfoWrapperPass>(); +} + +bool StackSafetyGlobalInfoWrapperPass::runOnModule(Module &M) { +  StackSafetyDataFlowAnalysis SSDFA( +      M, [this](Function &F) -> const StackSafetyInfo & { +        return getAnalysis<StackSafetyInfoWrapperPass>(F).getResult(); +      }); +  SSI = SSDFA.run(); +  return false; +} + +static const char LocalPassArg[] = "stack-safety-local"; +static const char LocalPassName[] = "Stack Safety Local Analysis"; +INITIALIZE_PASS_BEGIN(StackSafetyInfoWrapperPass, LocalPassArg, LocalPassName, +                      false, true) +INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass) +INITIALIZE_PASS_END(StackSafetyInfoWrapperPass, LocalPassArg, LocalPassName, +                    false, true) + +static const char GlobalPassName[] = "Stack Safety Analysis"; +INITIALIZE_PASS_BEGIN(StackSafetyGlobalInfoWrapperPass, DEBUG_TYPE, +                      GlobalPassName, false, false) +INITIALIZE_PASS_DEPENDENCY(StackSafetyInfoWrapperPass) +INITIALIZE_PASS_END(StackSafetyGlobalInfoWrapperPass, DEBUG_TYPE, +                    GlobalPassName, false, false)  | 
