text: //===--- APValue.cpp - Union class for APFloat/APSInt/Complex -------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  //  This file implements the APValue class.
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/AST/APValue.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/CharUnits.h"
  #include "clang/AST/DeclCXX.h"
  #include "clang/AST/Expr.h"
  #include "clang/AST/Type.h"
  #include "clang/Basic/Diagnostic.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/Support/raw_ostream.h"
  #include "llvm/Support/ErrorHandling.h"
  using namespace clang;
  
  namespace {
    struct LVBase {
      llvm::PointerIntPair<APValue::LValueBase, 1, bool> BaseAndIsOnePastTheEnd;
      CharUnits Offset;
      unsigned PathLength;
      unsigned CallIndex;
    };
  }
  
  struct APValue::LV : LVBase {
    static const unsigned InlinePathSpace =
        (MaxSize - sizeof(LVBase)) / sizeof(LValuePathEntry);
  
    /// Path - The sequence of base classes, fields and array indices to follow to
    /// walk from Base to the subobject. When performing GCC-style folding, there
    /// may not be such a path.
    union {
      LValuePathEntry Path[InlinePathSpace];
      LValuePathEntry *PathPtr;
    };
  
    LV() { PathLength = (unsigned)-1; }
    ~LV() { resizePath(0); }
  
    void resizePath(unsigned Length) {
      if (Length == PathLength)
        return;
      if (hasPathPtr())
        delete [] PathPtr;
      PathLength = Length;
      if (hasPathPtr())
        PathPtr = new LValuePathEntry[Length];
    }
  
    bool hasPath() const { return PathLength != (unsigned)-1; }
    bool hasPathPtr() const { return hasPath() && PathLength > InlinePathSpace; }
  
    LValuePathEntry *getPath() { return hasPathPtr() ? PathPtr : Path; }
    const LValuePathEntry *getPath() const {
      return hasPathPtr() ? PathPtr : Path;
    }
  };
  
  namespace {
    struct MemberPointerBase {
      llvm::PointerIntPair<const ValueDecl*, 1, bool> MemberAndIsDerivedMember;
      unsigned PathLength;
    };
  }
  
  struct APValue::MemberPointerData : MemberPointerBase {
    static const unsigned InlinePathSpace =
        (MaxSize - sizeof(MemberPointerBase)) / sizeof(const CXXRecordDecl*);
    typedef const CXXRecordDecl *PathElem;
    union {
      PathElem Path[InlinePathSpace];
      PathElem *PathPtr;
    };
  
    MemberPointerData() { PathLength = 0; }
    ~MemberPointerData() { resizePath(0); }
  
    void resizePath(unsigned Length) {
      if (Length == PathLength)
        return;
      if (hasPathPtr())
        delete [] PathPtr;
      PathLength = Length;
      if (hasPathPtr())
        PathPtr = new PathElem[Length];
    }
  
    bool hasPathPtr() const { return PathLength > InlinePathSpace; }
  
    PathElem *getPath() { return hasPathPtr() ? PathPtr : Path; }
    const PathElem *getPath() const {
      return hasPathPtr() ? PathPtr : Path;
    }
  };
  
  // FIXME: Reduce the malloc traffic here.
  
  APValue::Arr::Arr(unsigned NumElts, unsigned Size) :
    Elts(new APValue[NumElts + (NumElts != Size ? 1 : 0)]),
    NumElts(NumElts), ArrSize(Size) {}
  APValue::Arr::~Arr() { delete [] Elts; }
  
  APValue::StructData::StructData(unsigned NumBases, unsigned NumFields) :
    Elts(new APValue[NumBases+NumFields]),
    NumBases(NumBases), NumFields(NumFields) {}
  APValue::StructData::~StructData() {
    delete [] Elts;
  }
  
  APValue::UnionData::UnionData() : Field(0), Value(new APValue) {}
  APValue::UnionData::~UnionData () {
    delete Value;
  }
  
  APValue::APValue(const APValue &RHS) : Kind(Uninitialized) {
    switch (RHS.getKind()) {
    case Uninitialized:
      break;
    case Int:
      MakeInt();
      setInt(RHS.getInt());
      break;
    case Float:
      MakeFloat();
      setFloat(RHS.getFloat());
      break;
    case Vector:
      MakeVector();
      setVector(((const Vec *)(const char *)RHS.Data)->Elts,
                RHS.getVectorLength());
      break;
    case ComplexInt:
      MakeComplexInt();
      setComplexInt(RHS.getComplexIntReal(), RHS.getComplexIntImag());
      break;
    case ComplexFloat:
      MakeComplexFloat();
      setComplexFloat(RHS.getComplexFloatReal(), RHS.getComplexFloatImag());
      break;
    case LValue:
      MakeLValue();
      if (RHS.hasLValuePath())
        setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), RHS.getLValuePath(),
                  RHS.isLValueOnePastTheEnd(), RHS.getLValueCallIndex());
      else
        setLValue(RHS.getLValueBase(), RHS.getLValueOffset(), NoLValuePath(),
                  RHS.getLValueCallIndex());
      break;
    case Array:
      MakeArray(RHS.getArrayInitializedElts(), RHS.getArraySize());
      for (unsigned I = 0, N = RHS.getArrayInitializedElts(); I != N; ++I)
        getArrayInitializedElt(I) = RHS.getArrayInitializedElt(I);
      if (RHS.hasArrayFiller())
        getArrayFiller() = RHS.getArrayFiller();
      break;
    case Struct:
      MakeStruct(RHS.getStructNumBases(), RHS.getStructNumFields());
      for (unsigned I = 0, N = RHS.getStructNumBases(); I != N; ++I)
        getStructBase(I) = RHS.getStructBase(I);
      for (unsigned I = 0, N = RHS.getStructNumFields(); I != N; ++I)
        getStructField(I) = RHS.getStructField(I);
      break;
    case Union:
      MakeUnion();
      setUnion(RHS.getUnionField(), RHS.getUnionValue());
      break;
    case MemberPointer:
      MakeMemberPointer(RHS.getMemberPointerDecl(),
                        RHS.isMemberPointerToDerivedMember(),
                        RHS.getMemberPointerPath());
      break;
    case AddrLabelDiff:
      MakeAddrLabelDiff();
      setAddrLabelDiff(RHS.getAddrLabelDiffLHS(), RHS.getAddrLabelDiffRHS());
      break;
    }
  }
  
  void APValue::DestroyDataAndMakeUninit() {
    if (Kind == Int)
      ((APSInt*)(char*)Data)->~APSInt();
    else if (Kind == Float)
      ((APFloat*)(char*)Data)->~APFloat();
    else if (Kind == Vector)
      ((Vec*)(char*)Data)->~Vec();
    else if (Kind == ComplexInt)
      ((ComplexAPSInt*)(char*)Data)->~ComplexAPSInt();
    else if (Kind == ComplexFloat)
      ((ComplexAPFloat*)(char*)Data)->~ComplexAPFloat();
    else if (Kind == LValue)
      ((LV*)(char*)Data)->~LV();
    else if (Kind == Array)
      ((Arr*)(char*)Data)->~Arr();
    else if (Kind == Struct)
      ((StructData*)(char*)Data)->~StructData();
    else if (Kind == Union)
      ((UnionData*)(char*)Data)->~UnionData();
    else if (Kind == MemberPointer)
      ((MemberPointerData*)(char*)Data)->~MemberPointerData();
    else if (Kind == AddrLabelDiff)
      ((AddrLabelDiffData*)(char*)Data)->~AddrLabelDiffData();
    Kind = Uninitialized;
  }
  
  void APValue::swap(APValue &RHS) {
    std::swap(Kind, RHS.Kind);
    char TmpData[MaxSize];
    memcpy(TmpData, Data, MaxSize);
    memcpy(Data, RHS.Data, MaxSize);
    memcpy(RHS.Data, TmpData, MaxSize);
  }
  
  void APValue::dump() const {
    dump(llvm::errs());
    llvm::errs() << '\n';
  }
  
  static double GetApproxValue(const llvm::APFloat &F) {
    llvm::APFloat V = F;
    bool ignored;
    V.convert(llvm::APFloat::IEEEdouble, llvm::APFloat::rmNearestTiesToEven,
              &ignored);
    return V.convertToDouble();
  }
  
  void APValue::dump(raw_ostream &OS) const {
    switch (getKind()) {
    case Uninitialized:
      OS << "Uninitialized";
      return;
    case Int:
      OS << "Int: " << getInt();
      return;
    case Float:
      OS << "Float: " << GetApproxValue(getFloat());
      return;
    case Vector:
      OS << "Vector: ";
      getVectorElt(0).dump(OS);
      for (unsigned i = 1; i != getVectorLength(); ++i) {
        OS << ", ";
        getVectorElt(i).dump(OS);
      }
      return;
    case ComplexInt:
      OS << "ComplexInt: " << getComplexIntReal() << ", " << getComplexIntImag();
      return;
    case ComplexFloat:
      OS << "ComplexFloat: " << GetApproxValue(getComplexFloatReal())
         << ", " << GetApproxValue(getComplexFloatImag());
      return;
    case LValue:
      OS << "LValue: <todo>";
      return;
    case Array:
      OS << "Array: ";
      for (unsigned I = 0, N = getArrayInitializedElts(); I != N; ++I) {
        getArrayInitializedElt(I).dump(OS);
        if (I != getArraySize() - 1) OS << ", ";
      }
      if (hasArrayFiller()) {
        OS << getArraySize() - getArrayInitializedElts() << " x ";
        getArrayFiller().dump(OS);
      }
      return;
    case Struct:
      OS << "Struct ";
      if (unsigned N = getStructNumBases()) {
        OS << " bases: ";
        getStructBase(0).dump(OS);
        for (unsigned I = 1; I != N; ++I) {
          OS << ", ";
          getStructBase(I).dump(OS);
        }
      }
      if (unsigned N = getStructNumFields()) {
        OS << " fields: ";
        getStructField(0).dump(OS);
        for (unsigned I = 1; I != N; ++I) {
          OS << ", ";
          getStructField(I).dump(OS);
        }
      }
      return;
    case Union:
      OS << "Union: ";
      getUnionValue().dump(OS);
      return;
    case MemberPointer:
      OS << "MemberPointer: <todo>";
      return;
    case AddrLabelDiff:
      OS << "AddrLabelDiff: <todo>";
      return;
    }
    llvm_unreachable("Unknown APValue kind!");
  }
  
  void APValue::printPretty(raw_ostream &Out, ASTContext &Ctx, QualType Ty) const{
    switch (getKind()) {
    case APValue::Uninitialized:
      Out << "<uninitialized>";
      return;
    case APValue::Int:
      if (Ty->isBooleanType())
        Out << (getInt().getBoolValue() ? "true" : "false");
      else
        Out << getInt();
      return;
    case APValue::Float:
      Out << GetApproxValue(getFloat());
      return;
    case APValue::Vector: {
      Out << '{';
      QualType ElemTy = Ty->getAs<VectorType>()->getElementType();
      getVectorElt(0).printPretty(Out, Ctx, ElemTy);
      for (unsigned i = 1; i != getVectorLength(); ++i) {
        Out << ", ";
        getVectorElt(i).printPretty(Out, Ctx, ElemTy);
      }
      Out << '}';
      return;
    }
    case APValue::ComplexInt:
      Out << getComplexIntReal() << "+" << getComplexIntImag() << "i";
      return;
    case APValue::ComplexFloat:
      Out << GetApproxValue(getComplexFloatReal()) << "+"
          << GetApproxValue(getComplexFloatImag()) << "i";
      return;
    case APValue::LValue: {
      LValueBase Base = getLValueBase();
      if (!Base) {
        Out << "0";
        return;
      }
  
      bool IsReference = Ty->isReferenceType();
      QualType InnerTy
        = IsReference ? Ty.getNonReferenceType() : Ty->getPointeeType();
  
      if (!hasLValuePath()) {
        // No lvalue path: just print the offset.
        CharUnits O = getLValueOffset();
        CharUnits S = Ctx.getTypeSizeInChars(InnerTy);
        if (!O.isZero()) {
          if (IsReference)
            Out << "*(";
          if (O % S) {
            Out << "(char*)";
            S = CharUnits::One();
          }
          Out << '&';
        } else if (!IsReference)
          Out << '&';
  
        if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>())
          Out << *VD;
        else
          Base.get<const Expr*>()->printPretty(Out, 0, Ctx.getPrintingPolicy());
        if (!O.isZero()) {
          Out << " + " << (O / S);
          if (IsReference)
            Out << ')';
        }
        return;
      }
  
      // We have an lvalue path. Print it out nicely.
      if (!IsReference)
        Out << '&';
      else if (isLValueOnePastTheEnd())
        Out << "*(&";
  
      QualType ElemTy;
      if (const ValueDecl *VD = Base.dyn_cast<const ValueDecl*>()) {
        Out << *VD;
        ElemTy = VD->getType();
      } else {
        const Expr *E = Base.get<const Expr*>();
        E->printPretty(Out, 0, Ctx.getPrintingPolicy());
        ElemTy = E->getType();
      }
  
      ArrayRef<LValuePathEntry> Path = getLValuePath();
      const CXXRecordDecl *CastToBase = 0;
      for (unsigned I = 0, N = Path.size(); I != N; ++I) {
        if (ElemTy->getAs<RecordType>()) {
          // The lvalue refers to a class type, so the next path entry is a base
          // or member.
          const Decl *BaseOrMember =
          BaseOrMemberType::getFromOpaqueValue(Path[I].BaseOrMember).getPointer();
          if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(BaseOrMember)) {
            CastToBase = RD;
            ElemTy = Ctx.getRecordType(RD);
          } else {
            const ValueDecl *VD = cast<ValueDecl>(BaseOrMember);
            Out << ".";
            if (CastToBase)
              Out << *CastToBase << "::";
            Out << *VD;
            ElemTy = VD->getType();
          }
        } else {
          // The lvalue must refer to an array.
          Out << '[' << Path[I].ArrayIndex << ']';
          ElemTy = Ctx.getAsArrayType(ElemTy)->getElementType();
        }
      }
  
      // Handle formatting of one-past-the-end lvalues.
      if (isLValueOnePastTheEnd()) {
        // FIXME: If CastToBase is non-0, we should prefix the output with
        // "(CastToBase*)".
        Out << " + 1";
        if (IsReference)
          Out << ')';
      }
      return;
    }
    case APValue::Array: {
      const ArrayType *AT = Ctx.getAsArrayType(Ty);
      QualType ElemTy = AT->getElementType();
      Out << '{';
      if (unsigned N = getArrayInitializedElts()) {
        getArrayInitializedElt(0).printPretty(Out, Ctx, ElemTy);
        for (unsigned I = 1; I != N; ++I) {
          Out << ", ";
          if (I == 10) {
            // Avoid printing out the entire contents of large arrays.
            Out << "...";
            break;
          }
          getArrayInitializedElt(I).printPretty(Out, Ctx, ElemTy);
        }
      }
      Out << '}';
      return;
    }
    case APValue::Struct: {
      Out << '{';
      const RecordDecl *RD = Ty->getAs<RecordType>()->getDecl();
      bool First = true;
      if (unsigned N = getStructNumBases()) {
        const CXXRecordDecl *CD = cast<CXXRecordDecl>(RD);
        CXXRecordDecl::base_class_const_iterator BI = CD->bases_begin();
        for (unsigned I = 0; I != N; ++I, ++BI) {
          assert(BI != CD->bases_end());
          if (!First)
            Out << ", ";
          getStructBase(I).printPretty(Out, Ctx, BI->getType());
          First = false;
        }
      }
      for (RecordDecl::field_iterator FI = RD->field_begin();
           FI != RD->field_end(); ++FI) {
        if (!First)
          Out << ", ";
        if (FI->isUnnamedBitfield()) continue;
        getStructField(FI->getFieldIndex()).
          printPretty(Out, Ctx, FI->getType());
        First = false;
      }
      Out << '}';
      return;
    }
    case APValue::Union:
      Out << '{';
      if (const FieldDecl *FD = getUnionField()) {
        Out << "." << *FD << " = ";
        getUnionValue().printPretty(Out, Ctx, FD->getType());
      }
      Out << '}';
      return;
    case APValue::MemberPointer:
      // FIXME: This is not enough to unambiguously identify the member in a
      // multiple-inheritance scenario.
      if (const ValueDecl *VD = getMemberPointerDecl()) {
        Out << '&' << *cast<CXXRecordDecl>(VD->getDeclContext()) << "::" << *VD;
        return;
      }
      Out << "0";
      return;
    case APValue::AddrLabelDiff:
      Out << "&&" << getAddrLabelDiffLHS()->getLabel()->getName();
      Out << " - ";
      Out << "&&" << getAddrLabelDiffRHS()->getLabel()->getName();
      return;
    }
    llvm_unreachable("Unknown APValue kind!");
  }
  
  std::string APValue::getAsString(ASTContext &Ctx, QualType Ty) const {
    std::string Result;
    llvm::raw_string_ostream Out(Result);
    printPretty(Out, Ctx, Ty);
    Out.flush();
    return Result;
  }
  
  const APValue::LValueBase APValue::getLValueBase() const {
    assert(isLValue() && "Invalid accessor");
    return ((const LV*)(const void*)Data)->BaseAndIsOnePastTheEnd.getPointer();
  }
  
  bool APValue::isLValueOnePastTheEnd() const {
    assert(isLValue() && "Invalid accessor");
    return ((const LV*)(const void*)Data)->BaseAndIsOnePastTheEnd.getInt();
  }
  
  CharUnits &APValue::getLValueOffset() {
    assert(isLValue() && "Invalid accessor");
    return ((LV*)(void*)Data)->Offset;
  }
  
  bool APValue::hasLValuePath() const {
    assert(isLValue() && "Invalid accessor");
    return ((const LV*)(const char*)Data)->hasPath();
  }
  
  ArrayRef<APValue::LValuePathEntry> APValue::getLValuePath() const {
    assert(isLValue() && hasLValuePath() && "Invalid accessor");
    const LV &LVal = *((const LV*)(const char*)Data);
    return ArrayRef<LValuePathEntry>(LVal.getPath(), LVal.PathLength);
  }
  
  unsigned APValue::getLValueCallIndex() const {
    assert(isLValue() && "Invalid accessor");
    return ((const LV*)(const char*)Data)->CallIndex;
  }
  
  void APValue::setLValue(LValueBase B, const CharUnits &O, NoLValuePath,
                          unsigned CallIndex) {
    assert(isLValue() && "Invalid accessor");
    LV &LVal = *((LV*)(char*)Data);
    LVal.BaseAndIsOnePastTheEnd.setPointer(B);
    LVal.BaseAndIsOnePastTheEnd.setInt(false);
    LVal.Offset = O;
    LVal.CallIndex = CallIndex;
    LVal.resizePath((unsigned)-1);
  }
  
  void APValue::setLValue(LValueBase B, const CharUnits &O,
                          ArrayRef<LValuePathEntry> Path, bool IsOnePastTheEnd,
                          unsigned CallIndex) {
    assert(isLValue() && "Invalid accessor");
    LV &LVal = *((LV*)(char*)Data);
    LVal.BaseAndIsOnePastTheEnd.setPointer(B);
    LVal.BaseAndIsOnePastTheEnd.setInt(IsOnePastTheEnd);
    LVal.Offset = O;
    LVal.CallIndex = CallIndex;
    LVal.resizePath(Path.size());
    memcpy(LVal.getPath(), Path.data(), Path.size() * sizeof(LValuePathEntry));
  }
  
  const ValueDecl *APValue::getMemberPointerDecl() const {
    assert(isMemberPointer() && "Invalid accessor");
    const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
    return MPD.MemberAndIsDerivedMember.getPointer();
  }
  
  bool APValue::isMemberPointerToDerivedMember() const {
    assert(isMemberPointer() && "Invalid accessor");
    const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
    return MPD.MemberAndIsDerivedMember.getInt();
  }
  
  ArrayRef<const CXXRecordDecl*> APValue::getMemberPointerPath() const {
    assert(isMemberPointer() && "Invalid accessor");
    const MemberPointerData &MPD = *((const MemberPointerData*)(const char*)Data);
    return ArrayRef<const CXXRecordDecl*>(MPD.getPath(), MPD.PathLength);
  }
  
  void APValue::MakeLValue() {
    assert(isUninit() && "Bad state change");
    assert(sizeof(LV) <= MaxSize && "LV too big");
    new ((void*)(char*)Data) LV();
    Kind = LValue;
  }
  
  void APValue::MakeArray(unsigned InitElts, unsigned Size) {
    assert(isUninit() && "Bad state change");
    new ((void*)(char*)Data) Arr(InitElts, Size);
    Kind = Array;
  }
  
  void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
                                  ArrayRef<const CXXRecordDecl*> Path) {
    assert(isUninit() && "Bad state change");
    MemberPointerData *MPD = new ((void*)(char*)Data) MemberPointerData;
    Kind = MemberPointer;
    MPD->MemberAndIsDerivedMember.setPointer(Member);
    MPD->MemberAndIsDerivedMember.setInt(IsDerivedMember);
    MPD->resizePath(Path.size());
    memcpy(MPD->getPath(), Path.data(), Path.size()*sizeof(const CXXRecordDecl*));
  }
  