include/clang/AST/Type.h

//===--- Type.h - C Language Family Type Representation ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file defines the Type interface and subclasses.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_TYPE_H
#define LLVM_CLANG_AST_TYPE_H

#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/TemplateName.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/ExceptionSpecificationType.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/Linkage.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/Visibility.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ErrorHandling.h"

namespace clang {
  enum {
    TypeAlignmentInBits = 4,
    TypeAlignment = 1 << TypeAlignmentInBits
  };
  class Type;
  class ExtQuals;
  class QualType;
}

namespace llvm {
  template <typename T>
  class PointerLikeTypeTraits;
  template<>
  class PointerLikeTypeTraits< ::clang::Type*> {
  public:
    static inline void *getAsVoidPointer(::clang::Type *P) { return P; }
    static inline ::clang::Type *getFromVoidPointer(void *P) {
      return static_cast< ::clang::Type*>(P);
    }
    enum { NumLowBitsAvailable = clang::TypeAlignmentInBits };
  };
  template<>
  class PointerLikeTypeTraits< ::clang::ExtQuals*> {
  public:
    static inline void *getAsVoidPointer(::clang::ExtQuals *P) { return P; }
    static inline ::clang::ExtQuals *getFromVoidPointer(void *P) {
      return static_cast< ::clang::ExtQuals*>(P);
    }
    enum { NumLowBitsAvailable = clang::TypeAlignmentInBits };
  };

  template <>
  struct isPodLike<clang::QualType> { static const bool value = true; };
}

namespace clang {
  class ASTContext;
  class TypedefNameDecl;
  class TemplateDecl;
  class TemplateTypeParmDecl;
  class NonTypeTemplateParmDecl;
  class TemplateTemplateParmDecl;
  class TagDecl;
  class RecordDecl;
  class CXXRecordDecl;
  class EnumDecl;
  class FieldDecl;
  class FunctionDecl;
  class ObjCInterfaceDecl;
  class ObjCProtocolDecl;
  class ObjCMethodDecl;
  class UnresolvedUsingTypenameDecl;
  class Expr;
  class Stmt;
  class SourceLocation;
  class StmtIteratorBase;
  class TemplateArgument;
  class TemplateArgumentLoc;
  class TemplateArgumentListInfo;
  class ElaboratedType;
  class ExtQuals;
  class ExtQualsTypeCommonBase;
  struct PrintingPolicy;

  template <typename> class CanQual;
  typedef CanQual<Type> CanQualType;

  // Provide forward declarations for all of the *Type classes
#define TYPE(Class, Base) class Class##Type;
#include "clang/AST/TypeNodes.def"

/// Qualifiers - The collection of all-type qualifiers we support.
/// Clang supports five independent qualifiers:
/// * C99: const, volatile, and restrict
/// * Embedded C (TR18037): address spaces
/// * Objective C: the GC attributes (none, weak, or strong)
class Qualifiers {
public:
  enum TQ { // NOTE: These flags must be kept in sync with DeclSpec::TQ.
    Const    = 0x1,
    Restrict = 0x2,
    Volatile = 0x4,
    CVRMask = Const | Volatile | Restrict
  };

  enum GC {
    GCNone = 0,
    Weak,
    Strong
  };

  enum ObjCLifetime {
    /// There is no lifetime qualification on this type.
    OCL_None,

    /// This object can be modified without requiring retains or
    /// releases.
    OCL_ExplicitNone,

    /// Assigning into this object requires the old value to be
    /// released and the new value to be retained.  The timing of the
    /// release of the old value is inexact: it may be moved to
    /// immediately after the last known point where the value is
    /// live.
    OCL_Strong,

    /// Reading or writing from this object requires a barrier call.
    OCL_Weak,

    /// Assigning into this object requires a lifetime extension.
    OCL_Autoreleasing
  };

  enum {
    /// The maximum supported address space number.
    /// 24 bits should be enough for anyone.
    MaxAddressSpace = 0xffffffu,

    /// The width of the "fast" qualifier mask.
    FastWidth = 3,

    /// The fast qualifier mask.
    FastMask = (1 << FastWidth) - 1
  };

  Qualifiers() : Mask(0) {}

  /// \brief Returns the common set of qualifiers while removing them from
  /// the given sets.
  static Qualifiers removeCommonQualifiers(Qualifiers &L, Qualifiers &R) {
    // If both are only CVR-qualified, bit operations are sufficient.
    if (!(L.Mask & ~CVRMask) && !(R.Mask & ~CVRMask)) {
      Qualifiers Q;
      Q.Mask = L.Mask & R.Mask;
      L.Mask &= ~Q.Mask;
      R.Mask &= ~Q.Mask;
      return Q;
    }

    Qualifiers Q;
    unsigned CommonCRV = L.getCVRQualifiers() & R.getCVRQualifiers();
    Q.addCVRQualifiers(CommonCRV);
    L.removeCVRQualifiers(CommonCRV);
    R.removeCVRQualifiers(CommonCRV);

    if (L.getObjCGCAttr() == R.getObjCGCAttr()) {
      Q.setObjCGCAttr(L.getObjCGCAttr());
      L.removeObjCGCAttr();
      R.removeObjCGCAttr();
    }

    if (L.getObjCLifetime() == R.getObjCLifetime()) {
      Q.setObjCLifetime(L.getObjCLifetime());
      L.removeObjCLifetime();
      R.removeObjCLifetime();
    }

    if (L.getAddressSpace() == R.getAddressSpace()) {
      Q.setAddressSpace(L.getAddressSpace());
      L.removeAddressSpace();
      R.removeAddressSpace();
    }
    return Q;
  }

  static Qualifiers fromFastMask(unsigned Mask) {
    Qualifiers Qs;
    Qs.addFastQualifiers(Mask);
    return Qs;
  }

  static Qualifiers fromCVRMask(unsigned CVR) {
    Qualifiers Qs;
    Qs.addCVRQualifiers(CVR);
    return Qs;
  }

  // Deserialize qualifiers from an opaque representation.
  static Qualifiers fromOpaqueValue(unsigned opaque) {
    Qualifiers Qs;
    Qs.Mask = opaque;
    return Qs;
  }

  // Serialize these qualifiers into an opaque representation.
  unsigned getAsOpaqueValue() const {
    return Mask;
  }

  bool hasConst() const { return Mask & Const; }
  void setConst(bool flag) {
    Mask = (Mask & ~Const) | (flag ? Const : 0);
  }
  void removeConst() { Mask &= ~Const; }
  void addConst() { Mask |= Const; }

  bool hasVolatile() const { return Mask & Volatile; }
  void setVolatile(bool flag) {
    Mask = (Mask & ~Volatile) | (flag ? Volatile : 0);
  }
  void removeVolatile() { Mask &= ~Volatile; }
  void addVolatile() { Mask |= Volatile; }

  bool hasRestrict() const { return Mask & Restrict; }
  void setRestrict(bool flag) {
    Mask = (Mask & ~Restrict) | (flag ? Restrict : 0);
  }
  void removeRestrict() { Mask &= ~Restrict; }
  void addRestrict() { Mask |= Restrict; }

  bool hasCVRQualifiers() const { return getCVRQualifiers(); }
  unsigned getCVRQualifiers() const { return Mask & CVRMask; }
  void setCVRQualifiers(unsigned mask) {
    assert(!(mask & ~CVRMask) && "bitmask contains non-CVR bits");
    Mask = (Mask & ~CVRMask) | mask;
  }
  void removeCVRQualifiers(unsigned mask) {
    assert(!(mask & ~CVRMask) && "bitmask contains non-CVR bits");
    Mask &= ~mask;
  }
  void removeCVRQualifiers() {
    removeCVRQualifiers(CVRMask);
  }
  void addCVRQualifiers(unsigned mask) {
    assert(!(mask & ~CVRMask) && "bitmask contains non-CVR bits");
    Mask |= mask;
  }

  bool hasObjCGCAttr() const { return Mask & GCAttrMask; }
  GC getObjCGCAttr() const { return GC((Mask & GCAttrMask) >> GCAttrShift); }
  void setObjCGCAttr(GC type) {
    Mask = (Mask & ~GCAttrMask) | (type << GCAttrShift);
  }
  void removeObjCGCAttr() { setObjCGCAttr(GCNone); }
  void addObjCGCAttr(GC type) {
    assert(type);
    setObjCGCAttr(type);
  }
  Qualifiers withoutObjCGCAttr() const {
    Qualifiers qs = *this;
    qs.removeObjCGCAttr();
    return qs;
  }
  Qualifiers withoutObjCLifetime() const {
    Qualifiers qs = *this;
    qs.removeObjCLifetime();
    return qs;
  }

  bool hasObjCLifetime() const { return Mask & LifetimeMask; }
  ObjCLifetime getObjCLifetime() const {
    return ObjCLifetime((Mask & LifetimeMask) >> LifetimeShift);
  }
  void setObjCLifetime(ObjCLifetime type) {
    Mask = (Mask & ~LifetimeMask) | (type << LifetimeShift);
  }
  void removeObjCLifetime() { setObjCLifetime(OCL_None); }
  void addObjCLifetime(ObjCLifetime type) {
    assert(type);
    assert(!hasObjCLifetime());
    Mask |= (type << LifetimeShift);
  }

  /// True if the lifetime is neither None or ExplicitNone.
  bool hasNonTrivialObjCLifetime() const {
    ObjCLifetime lifetime = getObjCLifetime();
    return (lifetime > OCL_ExplicitNone);
  }

  /// True if the lifetime is either strong or weak.
  bool hasStrongOrWeakObjCLifetime() const {
    ObjCLifetime lifetime = getObjCLifetime();
    return (lifetime == OCL_Strong || lifetime == OCL_Weak);
  }

  bool hasAddressSpace() const { return Mask & AddressSpaceMask; }
  unsigned getAddressSpace() const { return Mask >> AddressSpaceShift; }
  void setAddressSpace(unsigned space) {
    assert(space <= MaxAddressSpace);
    Mask = (Mask & ~AddressSpaceMask)
         | (((uint32_t) space) << AddressSpaceShift);
  }
  void removeAddressSpace() { setAddressSpace(0); }
  void addAddressSpace(unsigned space) {
    assert(space);
    setAddressSpace(space);
  }

  // Fast qualifiers are those that can be allocated directly
  // on a QualType object.
  bool hasFastQualifiers() const { return getFastQualifiers(); }
  unsigned getFastQualifiers() const { return Mask & FastMask; }
  void setFastQualifiers(unsigned mask) {
    assert(!(mask & ~FastMask) && "bitmask contains non-fast qualifier bits");
    Mask = (Mask & ~FastMask) | mask;
  }
  void removeFastQualifiers(unsigned mask) {
    assert(!(mask & ~FastMask) && "bitmask contains non-fast qualifier bits");
    Mask &= ~mask;
  }
  void removeFastQualifiers() {
    removeFastQualifiers(FastMask);
  }
  void addFastQualifiers(unsigned mask) {
    assert(!(mask & ~FastMask) && "bitmask contains non-fast qualifier bits");
    Mask |= mask;
  }

  /// hasNonFastQualifiers - Return true if the set contains any
  /// qualifiers which require an ExtQuals node to be allocated.
  bool hasNonFastQualifiers() const { return Mask & ~FastMask; }
  Qualifiers getNonFastQualifiers() const {
    Qualifiers Quals = *this;
    Quals.setFastQualifiers(0);
    return Quals;
  }

  /// hasQualifiers - Return true if the set contains any qualifiers.
  bool hasQualifiers() const { return Mask; }
  bool empty() const { return !Mask; }

  /// \brief Add the qualifiers from the given set to this set.
  void addQualifiers(Qualifiers Q) {
    // If the other set doesn't have any non-boolean qualifiers, just
    // bit-or it in.
    if (!(Q.Mask & ~CVRMask))
      Mask |= Q.Mask;
    else {
      Mask |= (Q.Mask & CVRMask);
      if (Q.hasAddressSpace())
        addAddressSpace(Q.getAddressSpace());
      if (Q.hasObjCGCAttr())
        addObjCGCAttr(Q.getObjCGCAttr());
      if (Q.hasObjCLifetime())
        addObjCLifetime(Q.getObjCLifetime());
    }
  }

  /// \brief Remove the qualifiers from the given set from this set.
  void removeQualifiers(Qualifiers Q) {
    // If the other set doesn't have any non-boolean qualifiers, just
    // bit-and the inverse in.
    if (!(Q.Mask & ~CVRMask))
      Mask &= ~Q.Mask;
    else {
      Mask &= ~(Q.Mask & CVRMask);
      if (getObjCGCAttr() == Q.getObjCGCAttr())
        removeObjCGCAttr();
      if (getObjCLifetime() == Q.getObjCLifetime())
        removeObjCLifetime();
      if (getAddressSpace() == Q.getAddressSpace())
        removeAddressSpace();
    }
  }

  /// \brief Add the qualifiers from the given set to this set, given that
  /// they don't conflict.
  void addConsistentQualifiers(Qualifiers qs) {
    assert(getAddressSpace() == qs.getAddressSpace() ||
           !hasAddressSpace() || !qs.hasAddressSpace());
    assert(getObjCGCAttr() == qs.getObjCGCAttr() ||
           !hasObjCGCAttr() || !qs.hasObjCGCAttr());
    assert(getObjCLifetime() == qs.getObjCLifetime() ||
           !hasObjCLifetime() || !qs.hasObjCLifetime());
    Mask |= qs.Mask;
  }

  /// \brief Determines if these qualifiers compatibly include another set.
  /// Generally this answers the question of whether an object with the other
  /// qualifiers can be safely used as an object with these qualifiers.
  bool compatiblyIncludes(Qualifiers other) const {
    return
      // Address spaces must match exactly.
      getAddressSpace() == other.getAddressSpace() &&
      // ObjC GC qualifiers can match, be added, or be removed, but can't be
      // changed.
      (getObjCGCAttr() == other.getObjCGCAttr() ||
       !hasObjCGCAttr() || !other.hasObjCGCAttr()) &&
      // ObjC lifetime qualifiers must match exactly.
      getObjCLifetime() == other.getObjCLifetime() &&
      // CVR qualifiers may subset.
      (((Mask & CVRMask) | (other.Mask & CVRMask)) == (Mask & CVRMask));
  }

  /// \brief Determines if these qualifiers compatibly include another set of
  /// qualifiers from the narrow perspective of Objective-C ARC lifetime.
  ///
  /// One set of Objective-C lifetime qualifiers compatibly includes the other
  /// if the lifetime qualifiers match, or if both are non-__weak and the
  /// including set also contains the 'const' qualifier.
  bool compatiblyIncludesObjCLifetime(Qualifiers other) const {
    if (getObjCLifetime() == other.getObjCLifetime())
      return true;

    if (getObjCLifetime() == OCL_Weak || other.getObjCLifetime() == OCL_Weak)
      return false;

    return hasConst();
  }

  /// \brief Determine whether this set of qualifiers is a strict superset of
  /// another set of qualifiers, not considering qualifier compatibility.
  bool isStrictSupersetOf(Qualifiers Other) const;

  bool operator==(Qualifiers Other) const { return Mask == Other.Mask; }
  bool operator!=(Qualifiers Other) const { return Mask != Other.Mask; }

  LLVM_EXPLICIT operator bool() const { return hasQualifiers(); }

  Qualifiers &operator+=(Qualifiers R) {
    addQualifiers(R);
    return *this;
  }

  // Union two qualifier sets.  If an enumerated qualifier appears
  // in both sets, use the one from the right.
  friend Qualifiers operator+(Qualifiers L, Qualifiers R) {
    L += R;
    return L;
  }

  Qualifiers &operator-=(Qualifiers R) {
    removeQualifiers(R);
    return *this;
  }

  /// \brief Compute the difference between two qualifier sets.
  friend Qualifiers operator-(Qualifiers L, Qualifiers R) {
    L -= R;
    return L;
  }

  std::string getAsString() const;
  std::string getAsString(const PrintingPolicy &Policy) const;

  bool isEmptyWhenPrinted(const PrintingPolicy &Policy) const;
  void print(raw_ostream &OS, const PrintingPolicy &Policy,
             bool appendSpaceIfNonEmpty = false) const;

  void Profile(llvm::FoldingSetNodeID &ID) const {
    ID.AddInteger(Mask);
  }

private:

  // bits:     |0 1 2|3 .. 4|5  ..  7|8   ...   31|
  //           |C R V|GCAttr|Lifetime|AddressSpace|
  uint32_t Mask;

  static const uint32_t GCAttrMask = 0x18;
  static const uint32_t GCAttrShift = 3;
  static const uint32_t LifetimeMask = 0xE0;
  static const uint32_t LifetimeShift = 5;
  static const uint32_t AddressSpaceMask = ~(CVRMask|GCAttrMask|LifetimeMask);
  static const uint32_t AddressSpaceShift = 8;
};

/// A std::pair-like structure for storing a qualified type split
/// into its local qualifiers and its locally-unqualified type.
struct SplitQualType {
  /// The locally-unqualified type.
  const Type *Ty;

  /// The local qualifiers.
  Qualifiers Quals;

  SplitQualType() : Ty(0), Quals() {}
  SplitQualType(const Type *ty, Qualifiers qs) : Ty(ty), Quals(qs) {}

  SplitQualType getSingleStepDesugaredType() const; // end of this file

  // Make std::tie work.
  std::pair<const Type *,Qualifiers> asPair() const {
    return std::pair<const Type *, Qualifiers>(Ty, Quals);
  }

  friend bool operator==(SplitQualType a, SplitQualType b) {
    return a.Ty == b.Ty && a.Quals == b.Quals;
  }
  friend bool operator!=(SplitQualType a, SplitQualType b) {
    return a.Ty != b.Ty || a.Quals != b.Quals;
  }
};

/// QualType - For efficiency, we don't store CV-qualified types as nodes on
/// their own: instead each reference to a type stores the qualifiers.  This
/// greatly reduces the number of nodes we need to allocate for types (for
/// example we only need one for 'int', 'const int', 'volatile int',
/// 'const volatile int', etc).
///
/// As an added efficiency bonus, instead of making this a pair, we
/// just store the two bits we care about in the low bits of the
/// pointer.  To handle the packing/unpacking, we make QualType be a
/// simple wrapper class that acts like a smart pointer.  A third bit
/// indicates whether there are extended qualifiers present, in which
/// case the pointer points to a special structure.
class QualType {
  // Thankfully, these are efficiently composable.
  llvm::PointerIntPair<llvm::PointerUnion<const Type*,const ExtQuals*>,
                       Qualifiers::FastWidth> Value;

  const ExtQuals *getExtQualsUnsafe() const {
    return Value.getPointer().get<const ExtQuals*>();
  }

  const Type *getTypePtrUnsafe() const {
    return Value.getPointer().get<const Type*>();
  }

  const ExtQualsTypeCommonBase *getCommonPtr() const {
    assert(!isNull() && "Cannot retrieve a NULL type pointer");
    uintptr_t CommonPtrVal
      = reinterpret_cast<uintptr_t>(Value.getOpaqueValue());
    CommonPtrVal &= ~(uintptr_t)((1 << TypeAlignmentInBits) - 1);
    return reinterpret_cast<ExtQualsTypeCommonBase*>(CommonPtrVal);
  }

  friend class QualifierCollector;
public:
  QualType() {}

  QualType(const Type *Ptr, unsigned Quals)
    : Value(Ptr, Quals) {}
  QualType(const ExtQuals *Ptr, unsigned Quals)
    : Value(Ptr, Quals) {}

  unsigned getLocalFastQualifiers() const { return Value.getInt(); }
  void setLocalFastQualifiers(unsigned Quals) { Value.setInt(Quals); }

  /// Retrieves a pointer to the underlying (unqualified) type.
  ///
  /// This function requires that the type not be NULL. If the type might be
  /// NULL, use the (slightly less efficient) \c getTypePtrOrNull().
  const Type *getTypePtr() const;

  const Type *getTypePtrOrNull() const;

  /// Retrieves a pointer to the name of the base type.
  const IdentifierInfo *getBaseTypeIdentifier() const;

  /// Divides a QualType into its unqualified type and a set of local
  /// qualifiers.
  SplitQualType split() const;

  void *getAsOpaquePtr() const { return Value.getOpaqueValue(); }
  static QualType getFromOpaquePtr(const void *Ptr) {
    QualType T;
    T.Value.setFromOpaqueValue(const_cast<void*>(Ptr));
    return T;
  }

  const Type &operator*() const {
    return *getTypePtr();
  }

  const Type *operator->() const {
    return getTypePtr();
  }

  bool isCanonical() const;
  bool isCanonicalAsParam() const;

  /// isNull - Return true if this QualType doesn't point to a type yet.
  bool isNull() const {
    return Value.getPointer().isNull();
  }

  /// \brief Determine whether this particular QualType instance has the
  /// "const" qualifier set, without looking through typedefs that may have
  /// added "const" at a different level.
  bool isLocalConstQualified() const {
    return (getLocalFastQualifiers() & Qualifiers::Const);
  }

  /// \brief Determine whether this type is const-qualified.
  bool isConstQualified() const;

  /// \brief Determine whether this particular QualType instance has the
  /// "restrict" qualifier set, without looking through typedefs that may have
  /// added "restrict" at a different level.
  bool isLocalRestrictQualified() const {
    return (getLocalFastQualifiers() & Qualifiers::Restrict);
  }

  /// \brief Determine whether this type is restrict-qualified.
  bool isRestrictQualified() const;

  /// \brief Determine whether this particular QualType instance has the
  /// "volatile" qualifier set, without looking through typedefs that may have
  /// added "volatile" at a different level.
  bool isLocalVolatileQualified() const {
    return (getLocalFastQualifiers() & Qualifiers::Volatile);
  }

  /// \brief Determine whether this type is volatile-qualified.
  bool isVolatileQualified() const;

  /// \brief Determine whether this particular QualType instance has any
  /// qualifiers, without looking through any typedefs that might add
  /// qualifiers at a different level.
  bool hasLocalQualifiers() const {
    return getLocalFastQualifiers() || hasLocalNonFastQualifiers();
  }

  /// \brief Determine whether this type has any qualifiers.
  bool hasQualifiers() const;

  /// \brief Determine whether this particular QualType instance has any
  /// "non-fast" qualifiers, e.g., those that are stored in an ExtQualType
  /// instance.
  bool hasLocalNonFastQualifiers() const {
    return Value.getPointer().is<const ExtQuals*>();
  }

  /// \brief Retrieve the set of qualifiers local to this particular QualType
  /// instance, not including any qualifiers acquired through typedefs or
  /// other sugar.
  Qualifiers getLocalQualifiers() const;

  /// \brief Retrieve the set of qualifiers applied to this type.
  Qualifiers getQualifiers() const;

  /// \brief Retrieve the set of CVR (const-volatile-restrict) qualifiers
  /// local to this particular QualType instance, not including any qualifiers
  /// acquired through typedefs or other sugar.
  unsigned getLocalCVRQualifiers() const {
    return getLocalFastQualifiers();
  }

  /// \brief Retrieve the set of CVR (const-volatile-restrict) qualifiers
  /// applied to this type.
  unsigned getCVRQualifiers() const;

  bool isConstant(ASTContext& Ctx) const {
    return QualType::isConstant(*this, Ctx);
  }

  /// \brief Determine whether this is a Plain Old Data (POD) type (C++ 3.9p10).
  bool isPODType(ASTContext &Context) const;

  /// isCXX98PODType() - Return true if this is a POD type according to the
  /// rules of the C++98 standard, regardless of the current compilation's
  /// language.
  bool isCXX98PODType(ASTContext &Context) const;

  /// isCXX11PODType() - Return true if this is a POD type according to the
  /// more relaxed rules of the C++11 standard, regardless of the current
  /// compilation's language.
  /// (C++0x [basic.types]p9)
  bool isCXX11PODType(ASTContext &Context) const;

  /// isTrivialType - Return true if this is a trivial type
  /// (C++0x [basic.types]p9)
  bool isTrivialType(ASTContext &Context) const;

  /// isTriviallyCopyableType - Return true if this is a trivially
  /// copyable type (C++0x [basic.types]p9)
  bool isTriviallyCopyableType(ASTContext &Context) const;

  // Don't promise in the API that anything besides 'const' can be
  // easily added.

  /// addConst - add the specified type qualifier to this QualType.
  void addConst() {
    addFastQualifiers(Qualifiers::Const);
  }
  QualType withConst() const {
    return withFastQualifiers(Qualifiers::Const);
  }

  /// addVolatile - add the specified type qualifier to this QualType.
  void addVolatile() {
    addFastQualifiers(Qualifiers::Volatile);
  }
  QualType withVolatile() const {
    return withFastQualifiers(Qualifiers::Volatile);
  }
  
  /// Add the restrict qualifier to this QualType.
  void addRestrict() {
    addFastQualifiers(Qualifiers::Restrict);
  }
  QualType withRestrict() const {
    return withFastQualifiers(Qualifiers::Restrict);
  }

  QualType withCVRQualifiers(unsigned CVR) const {
    return withFastQualifiers(CVR);
  }

  void addFastQualifiers(unsigned TQs) {
    assert(!(TQs & ~Qualifiers::FastMask)
           && "non-fast qualifier bits set in mask!");
    Value.setInt(Value.getInt() | TQs);
  }

  void removeLocalConst();
  void removeLocalVolatile();
  void removeLocalRestrict();
  void removeLocalCVRQualifiers(unsigned Mask);

  void removeLocalFastQualifiers() { Value.setInt(0); }
  void removeLocalFastQualifiers(unsigned Mask) {
    assert(!(Mask & ~Qualifiers::FastMask) && "mask has non-fast qualifiers");
    Value.setInt(Value.getInt() & ~Mask);
  }

  // Creates a type with the given qualifiers in addition to any
  // qualifiers already on this type.
  QualType withFastQualifiers(unsigned TQs) const {
    QualType T = *this;
    T.addFastQualifiers(TQs);
    return T;
  }

  // Creates a type with exactly the given fast qualifiers, removing
  // any existing fast qualifiers.
  QualType withExactLocalFastQualifiers(unsigned TQs) const {
    return withoutLocalFastQualifiers().withFastQualifiers(TQs);
  }

  // Removes fast qualifiers, but leaves any extended qualifiers in place.
  QualType withoutLocalFastQualifiers() const {
    QualType T = *this;
    T.removeLocalFastQualifiers();
    return T;
  }

  QualType getCanonicalType() const;

  /// \brief Return this type with all of the instance-specific qualifiers
  /// removed, but without removing any qualifiers that may have been applied
  /// through typedefs.
  QualType getLocalUnqualifiedType() const { return QualType(getTypePtr(), 0); }

  /// \brief Retrieve the unqualified variant of the given type,
  /// removing as little sugar as possible.
  ///
  /// This routine looks through various kinds of sugar to find the
  /// least-desugared type that is unqualified. For example, given:
  ///
  /// \code
  /// typedef int Integer;
  /// typedef const Integer CInteger;
  /// typedef CInteger DifferenceType;
  /// \endcode
  ///
  /// Executing \c getUnqualifiedType() on the type \c DifferenceType will
  /// desugar until we hit the type \c Integer, which has no qualifiers on it.
  ///
  /// The resulting type might still be qualified if it's sugar for an array
  /// type.  To strip qualifiers even from within a sugared array type, use
  /// ASTContext::getUnqualifiedArrayType.
  inline QualType getUnqualifiedType() const;

  /// getSplitUnqualifiedType - Retrieve the unqualified variant of the
  /// given type, removing as little sugar as possible.
  ///
  /// Like getUnqualifiedType(), but also returns the set of
  /// qualifiers that were built up.
  ///
  /// The resulting type might still be qualified if it's sugar for an array
  /// type.  To strip qualifiers even from within a sugared array type, use
  /// ASTContext::getUnqualifiedArrayType.
  inline SplitQualType getSplitUnqualifiedType() const;

  /// \brief Determine whether this type is more qualified than the other
  /// given type, requiring exact equality for non-CVR qualifiers.
  bool isMoreQualifiedThan(QualType Other) const;

  /// \brief Determine whether this type is at least as qualified as the other
  /// given type, requiring exact equality for non-CVR qualifiers.
  bool isAtLeastAsQualifiedAs(QualType Other) const;

  QualType getNonReferenceType() const;

  /// \brief Determine the type of a (typically non-lvalue) expression with the
  /// specified result type.
  ///
  /// This routine should be used for expressions for which the return type is
  /// explicitly specified (e.g., in a cast or call) and isn't necessarily
  /// an lvalue. It removes a top-level reference (since there are no
  /// expressions of reference type) and deletes top-level cvr-qualifiers
  /// from non-class types (in C++) or all types (in C).
  QualType getNonLValueExprType(const ASTContext &Context) const;

  /// getDesugaredType - Return the specified type with any "sugar" removed from
  /// the type.  This takes off typedefs, typeof's etc.  If the outer level of
  /// the type is already concrete, it returns it unmodified.  This is similar
  /// to getting the canonical type, but it doesn't remove *all* typedefs.  For
  /// example, it returns "T*" as "T*", (not as "int*"), because the pointer is
  /// concrete.
  ///
  /// Qualifiers are left in place.
  QualType getDesugaredType(const ASTContext &Context) const {
    return getDesugaredType(*this, Context);
  }

  SplitQualType getSplitDesugaredType() const {
    return getSplitDesugaredType(*this);
  }

  /// \brief Return the specified type with one level of "sugar" removed from
  /// the type.
  ///
  /// This routine takes off the first typedef, typeof, etc. If the outer level
  /// of the type is already concrete, it returns it unmodified.
  QualType getSingleStepDesugaredType(const ASTContext &Context) const {
    return getSingleStepDesugaredTypeImpl(*this, Context);
  }

  /// IgnoreParens - Returns the specified type after dropping any
  /// outer-level parentheses.
  QualType IgnoreParens() const {
    if (isa<ParenType>(*this))
      return QualType::IgnoreParens(*this);
    return *this;
  }

  /// operator==/!= - Indicate whether the specified types and qualifiers are
  /// identical.
  friend bool operator==(const QualType &LHS, const QualType &RHS) {
    return LHS.Value == RHS.Value;
  }
  friend bool operator!=(const QualType &LHS, const QualType &RHS) {
    return LHS.Value != RHS.Value;
  }
  std::string getAsString() const {
    return getAsString(split());
  }
  static std::string getAsString(SplitQualType split) {
    return getAsString(split.Ty, split.Quals);
  }
  static std::string getAsString(const Type *ty, Qualifiers qs);

  std::string getAsString(const PrintingPolicy &Policy) const;

  void print(raw_ostream &OS, const PrintingPolicy &Policy,
             const Twine &PlaceHolder = Twine()) const {
    print(split(), OS, Policy, PlaceHolder);
  }
  static void print(SplitQualType split, raw_ostream &OS,
                    const PrintingPolicy &policy, const Twine &PlaceHolder) {
    return print(split.Ty, split.Quals, OS, policy, PlaceHolder);
  }
  static void print(const Type *ty, Qualifiers qs,
                    raw_ostream &OS, const PrintingPolicy &policy,
                    const Twine &PlaceHolder);

  void getAsStringInternal(std::string &Str,
                           const PrintingPolicy &Policy) const {
    return getAsStringInternal(split(), Str, Policy);
  }
  static void getAsStringInternal(SplitQualType split, std::string &out,
                                  const PrintingPolicy &policy) {
    return getAsStringInternal(split.Ty, split.Quals, out, policy);
  }
  static void getAsStringInternal(const Type *ty, Qualifiers qs,
                                  std::string &out,
                                  const PrintingPolicy &policy);

  class StreamedQualTypeHelper {
    const QualType &T;
    const PrintingPolicy &Policy;
    const Twine &PlaceHolder;
  public:
    StreamedQualTypeHelper(const QualType &T, const PrintingPolicy &Policy,
                           const Twine &PlaceHolder)
      : T(T), Policy(Policy), PlaceHolder(PlaceHolder) { }

    friend raw_ostream &operator<<(raw_ostream &OS,
                                   const StreamedQualTypeHelper &SQT) {
      SQT.T.print(OS, SQT.Policy, SQT.PlaceHolder);
      return OS;
    }
  };

  StreamedQualTypeHelper stream(const PrintingPolicy &Policy,
                                const Twine &PlaceHolder = Twine()) const {
    return StreamedQualTypeHelper(*this, Policy, PlaceHolder);
  }

  void dump(const char *s) const;
  void dump() const;

  void Profile(llvm::FoldingSetNodeID &ID) const {
    ID.AddPointer(getAsOpaquePtr());
  }

  /// getAddressSpace - Return the address space of this type.
  inline unsigned getAddressSpace() const;

  /// getObjCGCAttr - Returns gc attribute of this type.
  inline Qualifiers::GC getObjCGCAttr() const;

  /// isObjCGCWeak true when Type is objc's weak.
  bool isObjCGCWeak() const {
    return getObjCGCAttr() == Qualifiers::Weak;
  }

  /// isObjCGCStrong true when Type is objc's strong.
  bool isObjCGCStrong() const {
    return getObjCGCAttr() == Qualifiers::Strong;
  }

  /// getObjCLifetime - Returns lifetime attribute of this type.
  Qualifiers::ObjCLifetime getObjCLifetime() const {
    return getQualifiers().getObjCLifetime();
  }

  bool hasNonTrivialObjCLifetime() const {
    return getQualifiers().hasNonTrivialObjCLifetime();
  }

  bool hasStrongOrWeakObjCLifetime() const {
    return getQualifiers().hasStrongOrWeakObjCLifetime();
  }

  enum DestructionKind {
    DK_none,
    DK_cxx_destructor,
    DK_objc_strong_lifetime,
    DK_objc_weak_lifetime
  };

  /// isDestructedType - nonzero if objects of this type require
  /// non-trivial work to clean up after.  Non-zero because it's
  /// conceivable that qualifiers (objc_gc(weak)?) could make
  /// something require destruction.
  DestructionKind isDestructedType() const {
    return isDestructedTypeImpl(*this);
  }

  /// \brief Determine whether expressions of the given type are forbidden
  /// from being lvalues in C.
  ///
  /// The expression types that are forbidden to be lvalues are:
  ///   - 'void', but not qualified void
  ///   - function types
  ///
  /// The exact rule here is C99 6.3.2.1:
  ///   An lvalue is an expression with an object type or an incomplete
  ///   type other than void.
  bool isCForbiddenLValueType() const;

private:
  // These methods are implemented in a separate translation unit;
  // "static"-ize them to avoid creating temporary QualTypes in the
  // caller.
  static bool isConstant(QualType T, ASTContext& Ctx);
  static QualType getDesugaredType(QualType T, const ASTContext &Context);
  static SplitQualType getSplitDesugaredType(QualType T);
  static SplitQualType getSplitUnqualifiedTypeImpl(QualType type);
  static QualType getSingleStepDesugaredTypeImpl(QualType type,
                                                 const ASTContext &C);
  static QualType IgnoreParens(QualType T);
  static DestructionKind isDestructedTypeImpl(QualType type);
};

} // end clang.

namespace llvm {
/// Implement simplify_type for QualType, so that we can dyn_cast from QualType
/// to a specific Type class.
template<> struct simplify_type< ::clang::QualType> {
  typedef const ::clang::Type *SimpleType;
  static SimpleType getSimplifiedValue(::clang::QualType Val) {
    return Val.getTypePtr();
  }
};

// Teach SmallPtrSet that QualType is "basically a pointer".
template<>
class PointerLikeTypeTraits<clang::QualType> {
public:
  static inline void *getAsVoidPointer(clang::QualType P) {
    return P.getAsOpaquePtr();
  }
  static inline clang::QualType getFromVoidPointer(void *P) {
    return clang::QualType::getFromOpaquePtr(P);
  }
  // Various qualifiers go in low bits.
  enum { NumLowBitsAvailable = 0 };
};

} // end namespace llvm

namespace clang {

/// \brief Base class that is common to both the \c ExtQuals and \c Type
/// classes, which allows \c QualType to access the common fields between the
/// two.
///
class ExtQualsTypeCommonBase {
  ExtQualsTypeCommonBase(const Type *baseType, QualType canon)
    : BaseType(baseType), CanonicalType(canon) {}

  /// \brief The "base" type of an extended qualifiers type (\c ExtQuals) or
  /// a self-referential pointer (for \c Type).
  ///
  /// This pointer allows an efficient mapping from a QualType to its
  /// underlying type pointer.
  const Type *const BaseType;

  /// \brief The canonical type of this type.  A QualType.
  QualType CanonicalType;

  friend class QualType;
  friend class Type;
  friend class ExtQuals;
};

/// ExtQuals - We can encode up to four bits in the low bits of a
/// type pointer, but there are many more type qualifiers that we want
/// to be able to apply to an arbitrary type.  Therefore we have this
/// struct, intended to be heap-allocated and used by QualType to
/// store qualifiers.
///
/// The current design tags the 'const', 'restrict', and 'volatile' qualifiers
/// in three low bits on the QualType pointer; a fourth bit records whether
/// the pointer is an ExtQuals node. The extended qualifiers (address spaces,
/// Objective-C GC attributes) are much more rare.
class ExtQuals : public ExtQualsTypeCommonBase, public llvm::FoldingSetNode {
  // NOTE: changing the fast qualifiers should be straightforward as
  // long as you don't make 'const' non-fast.
  // 1. Qualifiers:
  //    a) Modify the bitmasks (Qualifiers::TQ and DeclSpec::TQ).
  //       Fast qualifiers must occupy the low-order bits.
  //    b) Update Qualifiers::FastWidth and FastMask.
  // 2. QualType:
  //    a) Update is{Volatile,Restrict}Qualified(), defined inline.
  //    b) Update remove{Volatile,Restrict}, defined near the end of
  //       this header.
  // 3. ASTContext:
  //    a) Update get{Volatile,Restrict}Type.

  /// Quals - the immutable set of qualifiers applied by this
  /// node;  always contains extended qualifiers.
  Qualifiers Quals;

  ExtQuals *this_() { return this; }

public:
  ExtQuals(const Type *baseType, QualType canon, Qualifiers quals)
    : ExtQualsTypeCommonBase(baseType,
                             canon.isNull() ? QualType(this_(), 0) : canon),
      Quals(quals)
  {
    assert(Quals.hasNonFastQualifiers()
           && "ExtQuals created with no fast qualifiers");
    assert(!Quals.hasFastQualifiers()
           && "ExtQuals created with fast qualifiers");
  }

  Qualifiers getQualifiers() const { return Quals; }

  bool hasObjCGCAttr() const { return Quals.hasObjCGCAttr(); }
  Qualifiers::GC getObjCGCAttr() const { return Quals.getObjCGCAttr(); }

  bool hasObjCLifetime() const { return Quals.hasObjCLifetime(); }
  Qualifiers::ObjCLifetime getObjCLifetime() const {
    return Quals.getObjCLifetime();
  }

  bool hasAddressSpace() const { return Quals.hasAddressSpace(); }
  unsigned getAddressSpace() const { return Quals.getAddressSpace(); }

  const Type *getBaseType() const { return BaseType; }

public:
  void Profile(llvm::FoldingSetNodeID &ID) const {
    Profile(ID, getBaseType(), Quals);
  }
  static void Profile(llvm::FoldingSetNodeID &ID,
                      const Type *BaseType,
                      Qualifiers Quals) {
    assert(!Quals.hasFastQualifiers() && "fast qualifiers in ExtQuals hash!");
    ID.AddPointer(BaseType);
    Quals.Profile(ID);
  }
};

/// \brief The kind of C++0x ref-qualifier associated with a function type,
/// which determines whether a member function's "this" object can be an
/// lvalue, rvalue, or neither.
enum RefQualifierKind {
  /// \brief No ref-qualifier was provided.
  RQ_None = 0,
  /// \brief An lvalue ref-qualifier was provided (\c &).
  RQ_LValue,
  /// \brief An rvalue ref-qualifier was provided (\c &&).
  RQ_RValue
};

/// Type - This is the base class of the type hierarchy.  A central concept
/// with types is that each type always has a canonical type.  A canonical type
/// is the type with any typedef names stripped out of it or the types it
/// references.  For example, consider:
///
///  typedef int  foo;
///  typedef foo* bar;
///    'int *'    'foo *'    'bar'
///
/// There will be a Type object created for 'int'.  Since int is canonical, its
/// canonicaltype pointer points to itself.  There is also a Type for 'foo' (a
/// TypedefType).  Its CanonicalType pointer points to the 'int' Type.  Next
/// there is a PointerType that represents 'int*', which, like 'int', is
/// canonical.  Finally, there is a PointerType type for 'foo*' whose canonical
/// type is 'int*', and there is a TypedefType for 'bar', whose canonical type
/// is also 'int*'.
///
/// Non-canonical types are useful for emitting diagnostics, without losing
/// information about typedefs being used.  Canonical types are useful for type
/// comparisons (they allow by-pointer equality tests) and useful for reasoning
/// about whether something has a particular form (e.g. is a function type),
/// because they implicitly, recursively, strip all typedefs out of a type.
///
/// Types, once created, are immutable.
///
class Type : public ExtQualsTypeCommonBase {
public:
  enum TypeClass {
#define TYPE(Class, Base) Class,
#define LAST_TYPE(Class) TypeLast = Class,
#define ABSTRACT_TYPE(Class, Base)
#include "clang/AST/TypeNodes.def"
    TagFirst = Record, TagLast = Enum
  };

private:
  Type(const Type &) LLVM_DELETED_FUNCTION;
  void operator=(const Type &) LLVM_DELETED_FUNCTION;

  /// Bitfields required by the Type class.
  class TypeBitfields {
    friend class Type;
    template <class T> friend class TypePropertyCache;

    /// TypeClass bitfield - Enum that specifies what subclass this belongs to.
    unsigned TC : 8;

    /// Dependent - Whether this type is a dependent type (C++ [temp.dep.type]).
    unsigned Dependent : 1;

    /// \brief Whether this type somehow involves a template parameter, even
    /// if the resolution of the type does not depend on a template parameter.
    unsigned InstantiationDependent : 1;

    /// \brief Whether this type is a variably-modified type (C99 6.7.5).
    unsigned VariablyModified : 1;

    /// \brief Whether this type contains an unexpanded parameter pack
    /// (for C++0x variadic templates).
    unsigned ContainsUnexpandedParameterPack : 1;

    /// \brief True if the cache (i.e. the bitfields here starting with
    /// 'Cache') is valid.
    mutable unsigned CacheValid : 1;

    /// \brief Linkage of this type.
    mutable unsigned CachedLinkage : 3;

    /// \brief Whether this type involves and local or unnamed types.
    mutable unsigned CachedLocalOrUnnamed : 1;

    /// \brief FromAST - Whether this type comes from an AST file.
    mutable unsigned FromAST : 1;

    bool isCacheValid() const {
      return CacheValid;
    }
    Linkage getLinkage() const {
      assert(isCacheValid() && "getting linkage from invalid cache");
      return static_cast<Linkage>(CachedLinkage);
    }
    bool hasLocalOrUnnamedType() const {
      assert(isCacheValid() && "getting linkage from invalid cache");
      return CachedLocalOrUnnamed;
    }
  };
  enum { NumTypeBits = 18 };

protected:
  // These classes allow subclasses to somewhat cleanly pack bitfields
  // into Type.

  class ArrayTypeBitfields {
    friend class ArrayType;

    unsigned : NumTypeBits;

    /// IndexTypeQuals - CVR qualifiers from declarations like
    /// 'int X[static restrict 4]'. For function parameters only.
    unsigned IndexTypeQuals : 3;

    /// SizeModifier - storage class qualifiers from declarations like
    /// 'int X[static restrict 4]'. For function parameters only.
    /// Actually an ArrayType::ArraySizeModifier.
    unsigned SizeModifier : 3;
  };

  class BuiltinTypeBitfields {
    friend class BuiltinType;

    unsigned : NumTypeBits;

    /// The kind (BuiltinType::Kind) of builtin type this is.
    unsigned Kind : 8;
  };

  class FunctionTypeBitfields {
    friend class FunctionType;

    unsigned : NumTypeBits;

    /// Extra information which affects how the function is called, like
    /// regparm and the calling convention.
    unsigned ExtInfo : 9;

    /// TypeQuals - Used only by FunctionProtoType, put here to pack with the
    /// other bitfields.
    /// The qualifiers are part of FunctionProtoType because...
    ///
    /// C++ 8.3.5p4: The return type, the parameter type list and the
    /// cv-qualifier-seq, [...], are part of the function type.
    unsigned TypeQuals : 3;
  };

  class ObjCObjectTypeBitfields {
    friend class ObjCObjectType;

    unsigned : NumTypeBits;

    /// NumProtocols - The number of protocols stored directly on this
    /// object type.
    unsigned NumProtocols : 32 - NumTypeBits;
  };

  class ReferenceTypeBitfields {
    friend class ReferenceType;

    unsigned : NumTypeBits;

    /// True if the type was originally spelled with an lvalue sigil.
    /// This is never true of rvalue references but can also be false
    /// on lvalue references because of C++0x [dcl.typedef]p9,
    /// as follows:
    ///
    ///   typedef int &ref;    // lvalue, spelled lvalue
    ///   typedef int &&rvref; // rvalue
    ///   ref &a;              // lvalue, inner ref, spelled lvalue
    ///   ref &&a;             // lvalue, inner ref
    ///   rvref &a;            // lvalue, inner ref, spelled lvalue
    ///   rvref &&a;           // rvalue, inner ref
    unsigned SpelledAsLValue : 1;

    /// True if the inner type is a reference type.  This only happens
    /// in non-canonical forms.
    unsigned InnerRef : 1;
  };

  class TypeWithKeywordBitfields {
    friend class TypeWithKeyword;

    unsigned : NumTypeBits;

    /// An ElaboratedTypeKeyword.  8 bits for efficient access.
    unsigned Keyword : 8;
  };

  class VectorTypeBitfields {
    friend class VectorType;

    unsigned : NumTypeBits;

    /// VecKind - The kind of vector, either a generic vector type or some
    /// target-specific vector type such as for AltiVec or Neon.
    unsigned VecKind : 3;

    /// NumElements - The number of elements in the vector.
    unsigned NumElements : 29 - NumTypeBits;

    enum { MaxNumElements = (1 << (29 - NumTypeBits)) - 1 };
  };

  class AttributedTypeBitfields {
    friend class AttributedType;

    unsigned : NumTypeBits;

    /// AttrKind - an AttributedType::Kind
    unsigned AttrKind : 32 - NumTypeBits;
  };

  class AutoTypeBitfields {
    friend class AutoType;

    unsigned : NumTypeBits;

    /// Was this placeholder type spelled as 'decltype(auto)'?
    unsigned IsDecltypeAuto : 1;
  };

  union {
    TypeBitfields TypeBits;
    ArrayTypeBitfields ArrayTypeBits;
    AttributedTypeBitfields AttributedTypeBits;
    AutoTypeBitfields AutoTypeBits;
    BuiltinTypeBitfields BuiltinTypeBits;
    FunctionTypeBitfields FunctionTypeBits;
    ObjCObjectTypeBitfields ObjCObjectTypeBits;
    ReferenceTypeBitfields ReferenceTypeBits;
    TypeWithKeywordBitfields TypeWithKeywordBits;
    VectorTypeBitfields VectorTypeBits;
  };

private:
  /// \brief Set whether this type comes from an AST file.
  void setFromAST(bool V = true) const {
    TypeBits.FromAST = V;
  }

  template <class T> friend class TypePropertyCache;

protected:
  // silence VC++ warning C4355: 'this' : used in base member initializer list
  Type *this_() { return this; }
  Type(TypeClass tc, QualType canon, bool Dependent,
       bool InstantiationDependent, bool VariablyModified,
       bool ContainsUnexpandedParameterPack)
    : ExtQualsTypeCommonBase(this,
                             canon.isNull() ? QualType(this_(), 0) : canon) {
    TypeBits.TC = tc;
    TypeBits.Dependent = Dependent;
    TypeBits.InstantiationDependent = Dependent || InstantiationDependent;
    TypeBits.VariablyModified = VariablyModified;
    TypeBits.ContainsUnexpandedParameterPack = ContainsUnexpandedParameterPack;
    TypeBits.CacheValid = false;
    TypeBits.CachedLocalOrUnnamed = false;
    TypeBits.CachedLinkage = NoLinkage;
    TypeBits.FromAST = false;
  }
  friend class ASTContext;

  void setDependent(bool D = true) {
    TypeBits.Dependent = D;
    if (D)
      TypeBits.InstantiationDependent = true;
  }
  void setInstantiationDependent(bool D = true) {
    TypeBits.InstantiationDependent = D; }
  void setVariablyModified(bool VM = true) { TypeBits.VariablyModified = VM;
  }
  void setContainsUnexpandedParameterPack(bool PP = true) {
    TypeBits.ContainsUnexpandedParameterPack = PP;
  }

public:
  TypeClass getTypeClass() const { return static_cast<TypeClass>(TypeBits.TC); }

  /// \brief Whether this type comes from an AST file.
  bool isFromAST() const { return TypeBits.FromAST; }

  /// \brief Whether this type is or contains an unexpanded parameter
  /// pack, used to support C++0x variadic templates.
  ///
  /// A type that contains a parameter pack shall be expanded by the
  /// ellipsis operator at some point. For example, the typedef in the
  /// following example contains an unexpanded parameter pack 'T':
  ///
  /// \code
  /// template<typename ...T>
  /// struct X {
  ///   typedef T* pointer_types; // ill-formed; T is a parameter pack.
  /// };
  /// \endcode
  ///
  /// Note that this routine does not specify which
  bool containsUnexpandedParameterPack() const {
    return TypeBits.ContainsUnexpandedParameterPack;
  }

  /// Determines if this type would be canonical if it had no further
  /// qualification.
  bool isCanonicalUnqualified() const {
    return CanonicalType == QualType(this, 0);
  }

  /// Pull a single level of sugar off of this locally-unqualified type.
  /// Users should generally prefer SplitQualType::getSingleStepDesugaredType()
  /// or QualType::getSingleStepDesugaredType(const ASTContext&).
  QualType getLocallyUnqualifiedSingleStepDesugaredType() const;

  /// Types are partitioned into 3 broad categories (C99 6.2.5p1):
  /// object types, function types, and incomplete types.

  /// isIncompleteType - Return true if this is an incomplete type.
  /// A type that can describe objects, but which lacks information needed to
  /// determine its size (e.g. void, or a fwd declared struct). Clients of this
  /// routine will need to determine if the size is actually required.
  ///
  /// \brief Def If non-NULL, and the type refers to some kind of declaration
  /// that can be completed (such as a C struct, C++ class, or Objective-C
  /// class), will be set to the declaration.
  bool isIncompleteType(NamedDecl **Def = 0) const;

  /// isIncompleteOrObjectType - Return true if this is an incomplete or object
  /// type, in other words, not a function type.
  bool isIncompleteOrObjectType() const {
    return !isFunctionType();
  }

  /// \brief Determine whether this type is an object type.
  bool isObjectType() const {
    // C++ [basic.types]p8:
    //   An object type is a (possibly cv-qualified) type that is not a
    //   function type, not a reference type, and not a void type.
    return !isReferenceType() && !isFunctionType() && !isVoidType();
  }

  /// isLiteralType - Return true if this is a literal type
  /// (C++11 [basic.types]p10)
  bool isLiteralType(const ASTContext &Ctx) const;

  /// \brief Test if this type is a standard-layout type.
  /// (C++0x [basic.type]p9)
  bool isStandardLayoutType() const;

  /// Helper methods to distinguish type categories. All type predicates
  /// operate on the canonical type, ignoring typedefs and qualifiers.

  /// isBuiltinType - returns true if the type is a builtin type.
  bool isBuiltinType() const;

  /// isSpecificBuiltinType - Test for a particular builtin type.
  bool isSpecificBuiltinType(unsigned K) const;

  /// isPlaceholderType - Test for a type which does not represent an
  /// actual type-system type but is instead used as a placeholder for
  /// various convenient purposes within Clang.  All such types are
  /// BuiltinTypes.
  bool isPlaceholderType() const;
  const BuiltinType *getAsPlaceholderType() const;

  /// isSpecificPlaceholderType - Test for a specific placeholder type.
  bool isSpecificPlaceholderType(unsigned K) const;

  /// isNonOverloadPlaceholderType - Test for a placeholder type
  /// other than Overload;  see BuiltinType::isNonOverloadPlaceholderType.
  bool isNonOverloadPlaceholderType() const;

  /// isIntegerType() does *not* include complex integers (a GCC extension).
  /// isComplexIntegerType() can be used to test for complex integers.
  bool isIntegerType() const;     // C99 6.2.5p17 (int, char, bool, enum)
  bool isEnumeralType() const;
  bool isBooleanType() const;
  bool isCharType() const;
  bool isWideCharType() const;
  bool isChar16Type() const;
  bool isChar32Type() const;
  bool isAnyCharacterType() const;
  bool isIntegralType(ASTContext &Ctx) const;

  /// \brief Determine whether this type is an integral or enumeration type.
  bool isIntegralOrEnumerationType() const;
  /// \brief Determine whether this type is an integral or unscoped enumeration
  /// type.
  bool isIntegralOrUnscopedEnumerationType() const;

  /// Floating point categories.
  bool isRealFloatingType() const; // C99 6.2.5p10 (float, double, long double)
  /// isComplexType() does *not* include complex integers (a GCC extension).
  /// isComplexIntegerType() can be used to test for complex integers.
  bool isComplexType() const;      // C99 6.2.5p11 (complex)
  bool isAnyComplexType() const;   // C99 6.2.5p11 (complex) + Complex Int.
  bool isFloatingType() const;     // C99 6.2.5p11 (real floating + complex)
  bool isHalfType() const;         // OpenCL 6.1.1.1, NEON (IEEE 754-2008 half)
  bool isRealType() const;         // C99 6.2.5p17 (real floating + integer)
  bool isArithmeticType() const;   // C99 6.2.5p18 (integer + floating)
  bool isVoidType() const;         // C99 6.2.5p19
  bool isScalarType() const;       // C99 6.2.5p21 (arithmetic + pointers)
  bool isAggregateType() const;
  bool isFundamentalType() const;
  bool isCompoundType() const;

  // Type Predicates: Check to see if this type is structurally the specified
  // type, ignoring typedefs and qualifiers.
  bool isFunctionType() const;
  bool isFunctionNoProtoType() const { return getAs<FunctionNoProtoType>(); }
  bool isFunctionProtoType() const { return getAs<FunctionProtoType>(); }
  bool isPointerType() const;
  bool isAnyPointerType() const;   // Any C pointer or ObjC object pointer
  bool isBlockPointerType() const;
  bool isVoidPointerType() const;
  bool isReferenceType() const;
  bool isLValueReferenceType() const;
  bool isRValueReferenceType() const;
  bool isFunctionPointerType() const;
  bool isMemberPointerType() const;
  bool isMemberFunctionPointerType() const;
  bool isMemberDataPointerType() const;
  bool isArrayType() const;
  bool isConstantArrayType() const;
  bool isIncompleteArrayType() const;
  bool isVariableArrayType() const;
  bool isDependentSizedArrayType() const;
  bool isRecordType() const;
  bool isClassType() const;
  bool isStructureType() const;
  bool isInterfaceType() const;
  bool isStructureOrClassType() const;
  bool isUnionType() const;
  bool isComplexIntegerType() const;            // GCC _Complex integer type.
  bool isVectorType() const;                    // GCC vector type.
  bool isExtVectorType() const;                 // Extended vector type.
  bool isObjCObjectPointerType() const;         // pointer to ObjC object
  bool isObjCRetainableType() const;            // ObjC object or block pointer
  bool isObjCLifetimeType() const;              // (array of)* retainable type
  bool isObjCIndirectLifetimeType() const;      // (pointer to)* lifetime type
  bool isObjCNSObjectType() const;              // __attribute__((NSObject))
  // FIXME: change this to 'raw' interface type, so we can used 'interface' type
  // for the common case.
  bool isObjCObjectType() const;                // NSString or typeof(*(id)0)
  bool isObjCQualifiedInterfaceType() const;    // NSString<foo>
  bool isObjCQualifiedIdType() const;           // id<foo>
  bool isObjCQualifiedClassType() const;        // Class<foo>
  bool isObjCObjectOrInterfaceType() const;
  bool isObjCIdType() const;                    // id
  bool isObjCClassType() const;                 // Class
  bool isObjCSelType() const;                 // Class
  bool isObjCBuiltinType() const;               // 'id' or 'Class'
  bool isObjCARCBridgableType() const;
  bool isCARCBridgableType() const;
  bool isTemplateTypeParmType() const;          // C++ template type parameter
  bool isNullPtrType() const;                   // C++0x nullptr_t
  bool isAtomicType() const;                    // C11 _Atomic()

  bool isImage1dT() const;                      // OpenCL image1d_t
  bool isImage1dArrayT() const;                 // OpenCL image1d_array_t
  bool isImage1dBufferT() const;                // OpenCL image1d_buffer_t
  bool isImage2dT() const;                      // OpenCL image2d_t
  bool isImage2dArrayT() const;                 // OpenCL image2d_array_t
  bool isImage3dT() const;                      // OpenCL image3d_t

  bool isImageType() const;                     // Any OpenCL image type

  bool isSamplerT() const;                      // OpenCL sampler_t
  bool isEventT() const;                        // OpenCL event_t

  bool isOpenCLSpecificType() const;            // Any OpenCL specific type

  /// Determines if this type, which must satisfy
  /// isObjCLifetimeType(), is implicitly __unsafe_unretained rather
  /// than implicitly __strong.
  bool isObjCARCImplicitlyUnretainedType() const;

  /// Return the implicit lifetime for this type, which must not be dependent.
  Qualifiers::ObjCLifetime getObjCARCImplicitLifetime() const;

  enum ScalarTypeKind {
    STK_CPointer,
    STK_BlockPointer,
    STK_ObjCObjectPointer,
    STK_MemberPointer,
    STK_Bool,
    STK_Integral,
    STK_Floating,
    STK_IntegralComplex,
    STK_FloatingComplex
  };
  /// getScalarTypeKind - Given that this is a scalar type, classify it.
  ScalarTypeKind getScalarTypeKind() const;

  /// isDependentType - Whether this type is a dependent type, meaning
  /// that its definition somehow depends on a template parameter
  /// (C++ [temp.dep.type]).
  bool isDependentType() const { return TypeBits.Dependent; }

  /// \brief Determine whether this type is an instantiation-dependent type,
  /// meaning that the type involves a template parameter (even if the
  /// definition does not actually depend on the type substituted for that
  /// template parameter).
  bool isInstantiationDependentType() const {
    return TypeBits.InstantiationDependent;
  }

  /// \brief Determine whether this type is an undeduced type, meaning that
  /// it somehow involves a C++11 'auto' type which has not yet been deduced.
  bool isUndeducedType() const;

  /// \brief Whether this type is a variably-modified type (C99 6.7.5).
  bool isVariablyModifiedType() const { return TypeBits.VariablyModified; }

  /// \brief Whether this type involves a variable-length array type
  /// with a definite size.
  bool hasSizedVLAType() const;

  /// \brief Whether this type is or contains a local or unnamed type.
  bool hasUnnamedOrLocalType() const;

  bool isOverloadableType() const;

  /// \brief Determine wither this type is a C++ elaborated-type-specifier.
  bool isElaboratedTypeSpecifier() const;

  bool canDecayToPointerType() const;

  /// hasPointerRepresentation - Whether this type is represented
  /// natively as a pointer; this includes pointers, references, block
  /// pointers, and Objective-C interface, qualified id, and qualified
  /// interface types, as well as nullptr_t.
  bool hasPointerRepresentation() const;

  /// hasObjCPointerRepresentation - Whether this type can represent
  /// an objective pointer type for the purpose of GC'ability
  bool hasObjCPointerRepresentation() const;

  /// \brief Determine whether this type has an integer representation
  /// of some sort, e.g., it is an integer type or a vector.
  bool hasIntegerRepresentation() const;

  /// \brief Determine whether this type has an signed integer representation
  /// of some sort, e.g., it is an signed integer type or a vector.
  bool hasSignedIntegerRepresentation() const;

  /// \brief Determine whether this type has an unsigned integer representation
  /// of some sort, e.g., it is an unsigned integer type or a vector.
  bool hasUnsignedIntegerRepresentation() const;

  /// \brief Determine whether this type has a floating-point representation
  /// of some sort, e.g., it is a floating-point type or a vector thereof.
  bool hasFloatingRepresentation() const;

  // Type Checking Functions: Check to see if this type is structurally the
  // specified type, ignoring typedefs and qualifiers, and return a pointer to
  // the best type we can.
  const RecordType *getAsStructureType() const;
  /// NOTE: getAs*ArrayType are methods on ASTContext.
  const RecordType *getAsUnionType() const;
  const ComplexType *getAsComplexIntegerType() const; // GCC complex int type.
  // The following is a convenience method that returns an ObjCObjectPointerType
  // for object declared using an interface.
  const ObjCObjectPointerType *getAsObjCInterfacePointerType() const;
  const ObjCObjectPointerType *getAsObjCQualifiedIdType() const;
  const ObjCObjectPointerType *getAsObjCQualifiedClassType() const;
  const ObjCObjectType *getAsObjCQualifiedInterfaceType() const;

  /// \brief Retrieves the CXXRecordDecl that this type refers to, either
  /// because the type is a RecordType or because it is the injected-class-name
  /// type of a class template or class template partial specialization.
  CXXRecordDecl *getAsCXXRecordDecl() const;

  /// If this is a pointer or reference to a RecordType, return the
  /// CXXRecordDecl that that type refers to.
  ///
  /// If this is not a pointer or reference, or the type being pointed to does
  /// not refer to a CXXRecordDecl, returns NULL.
  const CXXRecordDecl *getPointeeCXXRecordDecl() const;

  /// \brief Get the AutoType whose type will be deduced for a variable with
  /// an initializer of this type. This looks through declarators like pointer
  /// types, but not through decltype or typedefs.
  AutoType *getContainedAutoType() const;

  /// Member-template getAs<specific type>'.  Look through sugar for
  /// an instance of \<specific type>.   This scheme will eventually
  /// replace the specific getAsXXXX methods above.
  ///
  /// There are some specializations of this member template listed
  /// immediately following this class.
  template <typename T> const T *getAs() const;

  /// A variant of getAs<> for array types which silently discards
  /// qualifiers from the outermost type.
  const ArrayType *getAsArrayTypeUnsafe() const;

  /// Member-template castAs<specific type>.  Look through sugar for
  /// the underlying instance of \<specific type>.
  ///
  /// This method has the same relationship to getAs<T> as cast<T> has
  /// to dyn_cast<T>; which is to say, the underlying type *must*
  /// have the intended type, and this method will never return null.
  template <typename T> const T *castAs() const;

  /// A variant of castAs<> for array type which silently discards
  /// qualifiers from the outermost type.
  const ArrayType *castAsArrayTypeUnsafe() const;

  /// getBaseElementTypeUnsafe - Get the base element type of this
  /// type, potentially discarding type qualifiers.  This method
  /// should never be used when type qualifiers are meaningful.
  const Type *getBaseElementTypeUnsafe() const;

  /// getArrayElementTypeNoTypeQual - If this is an array type, return the
  /// element type of the array, potentially with type qualifiers missing.
  /// This method should never be used when type qualifiers are meaningful.
  const Type *getArrayElementTypeNoTypeQual() const;

  /// getPointeeType - If this is a pointer, ObjC object pointer, or block
  /// pointer, this returns the respective pointee.
  QualType getPointeeType() const;

  /// getUnqualifiedDesugaredType() - Return the specified type with
  /// any "sugar" removed from the type, removing any typedefs,
  /// typeofs, etc., as well as any qualifiers.
  const Type *getUnqualifiedDesugaredType() const;

  /// More type predicates useful for type checking/promotion
  bool isPromotableIntegerType() const; // C99 6.3.1.1p2

  /// isSignedIntegerType - Return true if this is an integer type that is
  /// signed, according to C99 6.2.5p4 [char, signed char, short, int, long..],
  /// or an enum decl which has a signed representation.
  bool isSignedIntegerType() const;

  /// isUnsignedIntegerType - Return true if this is an integer type that is
  /// unsigned, according to C99 6.2.5p6 [which returns true for _Bool],
  /// or an enum decl which has an unsigned representation.
  bool isUnsignedIntegerType() const;

  /// Determines whether this is an integer type that is signed or an
  /// enumeration types whose underlying type is a signed integer type.
  bool isSignedIntegerOrEnumerationType() const;

  /// Determines whether this is an integer type that is unsigned or an
  /// enumeration types whose underlying type is a unsigned integer type.
  bool isUnsignedIntegerOrEnumerationType() const;

  /// isConstantSizeType - Return true if this is not a variable sized type,
  /// according to the rules of C99 6.7.5p3.  It is not legal to call this on
  /// incomplete types.
  bool isConstantSizeType() const;

  /// isSpecifierType - Returns true if this type can be represented by some
  /// set of type specifiers.
  bool isSpecifierType() const;

  /// \brief Determine the linkage of this type.
  Linkage getLinkage() const;

  /// \brief Determine the visibility of this type.
  Visibility getVisibility() const {
    return getLinkageAndVisibility().getVisibility();
  }

  /// \brief Return true if the visibility was explicitly set is the code.
  bool isVisibilityExplicit() const {
    return getLinkageAndVisibility().isVisibilityExplicit();
  }

  /// \brief Determine the linkage and visibility of this type.
  LinkageInfo getLinkageAndVisibility() const;

  /// \brief True if the computed linkage is valid. Used for consistency
  /// checking. Should always return true.
  bool isLinkageValid() const;

  const char *getTypeClassName() const;

  QualType getCanonicalTypeInternal() const {
    return CanonicalType;
  }
  CanQualType getCanonicalTypeUnqualified() const; // in CanonicalType.h
  void dump() const;

  friend class ASTReader;
  friend class ASTWriter;
};

/// \brief This will check for a TypedefType by removing any existing sugar
/// until it reaches a TypedefType or a non-sugared type.
template <> const TypedefType *Type::getAs() const;

/// \brief This will check for a TemplateSpecializationType by removing any
/// existing sugar until it reaches a TemplateSpecializationType or a
/// non-sugared type.
template <> const TemplateSpecializationType *Type::getAs() const;

/// \brief This will check for an AttributedType by removing any existing sugar
/// until it reaches an AttributedType or a non-sugared type.
template <> const AttributedType *Type::getAs() const;

// We can do canonical leaf types faster, because we don't have to
// worry about preserving child type decoration.
#define TYPE(Class, Base)
#define LEAF_TYPE(Class) \
template <> inline const Class##Type *Type::getAs() const { \
  return dyn_cast<Class##Type>(CanonicalType); \
} \
template <> inline const Class##Type *Type::castAs() const { \
  return cast<Class##Type>(CanonicalType); \
}
#include "clang/AST/TypeNodes.def"


/// BuiltinType - This class is used for builtin types like 'int'.  Builtin
/// types are always canonical and have a literal name field.
class BuiltinType : public Type {
public:
  enum Kind {
#define BUILTIN_TYPE(Id, SingletonId) Id,
#define LAST_BUILTIN_TYPE(Id) LastKind = Id
#include "clang/AST/BuiltinTypes.def"
  };

public:
  BuiltinType(Kind K)
    : Type(Builtin, QualType(), /*Dependent=*/(K == Dependent),
           /*InstantiationDependent=*/(K == Dependent),
           /*VariablyModified=*/false,
           /*Unexpanded paramter pack=*/false) {
    BuiltinTypeBits.Kind = K;
  }

  Kind getKind() const { return static_cast<Kind>(BuiltinTypeBits.Kind); }
  StringRef getName(const PrintingPolicy &Policy) const;
  const char *getNameAsCString(const PrintingPolicy &Policy) const {
    // The StringRef is null-terminated.
    StringRef str = getName(Policy);
    assert(!str.empty() && str.data()[str.size()] == '\0');
    return str.data();
  }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  bool isInteger() const {
    return getKind() >= Bool && getKind() <= Int128;
  }

  bool isSignedInteger() const {
    return getKind() >= Char_S && getKind() <= Int128;
  }

  bool isUnsignedInteger() const {
    return getKind() >= Bool && getKind() <= UInt128;
  }

  bool isFloatingPoint() const {
    return getKind() >= Half && getKind() <= LongDouble;
  }

  /// Determines whether the given kind corresponds to a placeholder type.
  static bool isPlaceholderTypeKind(Kind K) {
    return K >= Overload;
  }

  /// Determines whether this type is a placeholder type, i.e. a type
  /// which cannot appear in arbitrary positions in a fully-formed
  /// expression.
  bool isPlaceholderType() const {
    return isPlaceholderTypeKind(getKind());
  }

  /// Determines whether this type is a placeholder type other than
  /// Overload.  Most placeholder types require only syntactic
  /// information about their context in order to be resolved (e.g.
  /// whether it is a call expression), which means they can (and
  /// should) be resolved in an earlier "phase" of analysis.
  /// Overload expressions sometimes pick up further information
  /// from their context, like whether the context expects a
  /// specific function-pointer type, and so frequently need
  /// special treatment.
  bool isNonOverloadPlaceholderType() const {
    return getKind() > Overload;
  }

  static bool classof(const Type *T) { return T->getTypeClass() == Builtin; }
};

/// ComplexType - C99 6.2.5p11 - Complex values.  This supports the C99 complex
/// types (_Complex float etc) as well as the GCC integer complex extensions.
///
class ComplexType : public Type, public llvm::FoldingSetNode {
  QualType ElementType;
  ComplexType(QualType Element, QualType CanonicalPtr) :
    Type(Complex, CanonicalPtr, Element->isDependentType(),
         Element->isInstantiationDependentType(),
         Element->isVariablyModifiedType(),
         Element->containsUnexpandedParameterPack()),
    ElementType(Element) {
  }
  friend class ASTContext;  // ASTContext creates these.

public:
  QualType getElementType() const { return ElementType; }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getElementType());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Element) {
    ID.AddPointer(Element.getAsOpaquePtr());
  }

  static bool classof(const Type *T) { return T->getTypeClass() == Complex; }
};

/// ParenType - Sugar for parentheses used when specifying types.
///
class ParenType : public Type, public llvm::FoldingSetNode {
  QualType Inner;

  ParenType(QualType InnerType, QualType CanonType) :
    Type(Paren, CanonType, InnerType->isDependentType(),
         InnerType->isInstantiationDependentType(),
         InnerType->isVariablyModifiedType(),
         InnerType->containsUnexpandedParameterPack()),
    Inner(InnerType) {
  }
  friend class ASTContext;  // ASTContext creates these.

public:

  QualType getInnerType() const { return Inner; }

  bool isSugared() const { return true; }
  QualType desugar() const { return getInnerType(); }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getInnerType());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Inner) {
    Inner.Profile(ID);
  }

  static bool classof(const Type *T) { return T->getTypeClass() == Paren; }
};

/// PointerType - C99 6.7.5.1 - Pointer Declarators.
///
class PointerType : public Type, public llvm::FoldingSetNode {
  QualType PointeeType;

  PointerType(QualType Pointee, QualType CanonicalPtr) :
    Type(Pointer, CanonicalPtr, Pointee->isDependentType(),
         Pointee->isInstantiationDependentType(),
         Pointee->isVariablyModifiedType(),
         Pointee->containsUnexpandedParameterPack()),
    PointeeType(Pointee) {
  }
  friend class ASTContext;  // ASTContext creates these.

public:

  QualType getPointeeType() const { return PointeeType; }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getPointeeType());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Pointee) {
    ID.AddPointer(Pointee.getAsOpaquePtr());
  }

  static bool classof(const Type *T) { return T->getTypeClass() == Pointer; }
};

/// \brief Represents a type which was implicitly adjusted by the semantic
/// engine for arbitrary reasons.  For example, array and function types can
/// decay, and function types can have their calling conventions adjusted.
class AdjustedType : public Type, public llvm::FoldingSetNode {
  QualType OriginalTy;
  QualType AdjustedTy;

protected:
  AdjustedType(TypeClass TC, QualType OriginalTy, QualType AdjustedTy,
               QualType CanonicalPtr)
      : Type(TC, CanonicalPtr, OriginalTy->isDependentType(),
             OriginalTy->isInstantiationDependentType(),
             OriginalTy->isVariablyModifiedType(),
             OriginalTy->containsUnexpandedParameterPack()),
        OriginalTy(OriginalTy), AdjustedTy(AdjustedTy) {}

  friend class ASTContext;  // ASTContext creates these.

public:
  QualType getOriginalType() const { return OriginalTy; }
  QualType getAdjustedType() const { return AdjustedTy; }

  bool isSugared() const { return true; }
  QualType desugar() const { return AdjustedTy; }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, OriginalTy, AdjustedTy);
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Orig, QualType New) {
    ID.AddPointer(Orig.getAsOpaquePtr());
    ID.AddPointer(New.getAsOpaquePtr());
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == Adjusted || T->getTypeClass() == Decayed;
  }
};

/// \brief Represents a pointer type decayed from an array or function type.
class DecayedType : public AdjustedType {

  DecayedType(QualType OriginalType, QualType DecayedPtr, QualType CanonicalPtr)
      : AdjustedType(Decayed, OriginalType, DecayedPtr, CanonicalPtr) {
    assert(isa<PointerType>(getAdjustedType()));
  }

  friend class ASTContext;  // ASTContext creates these.

public:
  QualType getDecayedType() const { return getAdjustedType(); }

  QualType getPointeeType() const {
    return cast<PointerType>(getDecayedType())->getPointeeType();
  }

  static bool classof(const Type *T) { return T->getTypeClass() == Decayed; }
};

/// BlockPointerType - pointer to a block type.
/// This type is to represent types syntactically represented as
/// "void (^)(int)", etc. Pointee is required to always be a function type.
///
class BlockPointerType : public Type, public llvm::FoldingSetNode {
  QualType PointeeType;  // Block is some kind of pointer type
  BlockPointerType(QualType Pointee, QualType CanonicalCls) :
    Type(BlockPointer, CanonicalCls, Pointee->isDependentType(),
         Pointee->isInstantiationDependentType(),
         Pointee->isVariablyModifiedType(),
         Pointee->containsUnexpandedParameterPack()),
    PointeeType(Pointee) {
  }
  friend class ASTContext;  // ASTContext creates these.

public:

  // Get the pointee type. Pointee is required to always be a function type.
  QualType getPointeeType() const { return PointeeType; }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  void Profile(llvm::FoldingSetNodeID &ID) {
      Profile(ID, getPointeeType());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Pointee) {
      ID.AddPointer(Pointee.getAsOpaquePtr());
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == BlockPointer;
  }
};

/// ReferenceType - Base for LValueReferenceType and RValueReferenceType
///
class ReferenceType : public Type, public llvm::FoldingSetNode {
  QualType PointeeType;

protected:
  ReferenceType(TypeClass tc, QualType Referencee, QualType CanonicalRef,
                bool SpelledAsLValue) :
    Type(tc, CanonicalRef, Referencee->isDependentType(),
         Referencee->isInstantiationDependentType(),
         Referencee->isVariablyModifiedType(),
         Referencee->containsUnexpandedParameterPack()),
    PointeeType(Referencee)
  {
    ReferenceTypeBits.SpelledAsLValue = SpelledAsLValue;
    ReferenceTypeBits.InnerRef = Referencee->isReferenceType();
  }

public:
  bool isSpelledAsLValue() const { return ReferenceTypeBits.SpelledAsLValue; }
  bool isInnerRef() const { return ReferenceTypeBits.InnerRef; }

  QualType getPointeeTypeAsWritten() const { return PointeeType; }
  QualType getPointeeType() const {
    // FIXME: this might strip inner qualifiers; okay?
    const ReferenceType *T = this;
    while (T->isInnerRef())
      T = T->PointeeType->castAs<ReferenceType>();
    return T->PointeeType;
  }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, PointeeType, isSpelledAsLValue());
  }
  static void Profile(llvm::FoldingSetNodeID &ID,
                      QualType Referencee,
                      bool SpelledAsLValue) {
    ID.AddPointer(Referencee.getAsOpaquePtr());
    ID.AddBoolean(SpelledAsLValue);
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == LValueReference ||
           T->getTypeClass() == RValueReference;
  }
};

/// LValueReferenceType - C++ [dcl.ref] - Lvalue reference
///
class LValueReferenceType : public ReferenceType {
  LValueReferenceType(QualType Referencee, QualType CanonicalRef,
                      bool SpelledAsLValue) :
    ReferenceType(LValueReference, Referencee, CanonicalRef, SpelledAsLValue)
  {}
  friend class ASTContext; // ASTContext creates these
public:
  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == LValueReference;
  }
};

/// RValueReferenceType - C++0x [dcl.ref] - Rvalue reference
///
class RValueReferenceType : public ReferenceType {
  RValueReferenceType(QualType Referencee, QualType CanonicalRef) :
    ReferenceType(RValueReference, Referencee, CanonicalRef, false) {
  }
  friend class ASTContext; // ASTContext creates these
public:
  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == RValueReference;
  }
};

/// MemberPointerType - C++ 8.3.3 - Pointers to members
///
class MemberPointerType : public Type, public llvm::FoldingSetNode {
  QualType PointeeType;
  /// The class of which the pointee is a member. Must ultimately be a
  /// RecordType, but could be a typedef or a template parameter too.
  const Type *Class;

  MemberPointerType(QualType Pointee, const Type *Cls, QualType CanonicalPtr) :
    Type(MemberPointer, CanonicalPtr,
         Cls->isDependentType() || Pointee->isDependentType(),
         (Cls->isInstantiationDependentType() ||
          Pointee->isInstantiationDependentType()),
         Pointee->isVariablyModifiedType(),
         (Cls->containsUnexpandedParameterPack() ||
          Pointee->containsUnexpandedParameterPack())),
    PointeeType(Pointee), Class(Cls) {
  }
  friend class ASTContext; // ASTContext creates these.

public:
  QualType getPointeeType() const { return PointeeType; }

  /// Returns true if the member type (i.e. the pointee type) is a
  /// function type rather than a data-member type.
  bool isMemberFunctionPointer() const {
    return PointeeType->isFunctionProtoType();
  }

  /// Returns true if the member type (i.e. the pointee type) is a
  /// data type rather than a function type.
  bool isMemberDataPointer() const {
    return !PointeeType->isFunctionProtoType();
  }

  const Type *getClass() const { return Class; }
  CXXRecordDecl *getMostRecentCXXRecordDecl() const;

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getPointeeType(), getClass());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType Pointee,
                      const Type *Class) {
    ID.AddPointer(Pointee.getAsOpaquePtr());
    ID.AddPointer(Class);
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == MemberPointer;
  }
};

/// ArrayType - C99 6.7.5.2 - Array Declarators.
///
class ArrayType : public Type, public llvm::FoldingSetNode {
public:
  /// ArraySizeModifier - Capture whether this is a normal array (e.g. int X[4])
  /// an array with a static size (e.g. int X[static 4]), or an array
  /// with a star size (e.g. int X[*]).
  /// 'static' is only allowed on function parameters.
  enum ArraySizeModifier {
    Normal, Static, Star
  };
private:
  /// ElementType - The element type of the array.
  QualType ElementType;

protected:
  // C++ [temp.dep.type]p1:
  //   A type is dependent if it is...
  //     - an array type constructed from any dependent type or whose
  //       size is specified by a constant expression that is
  //       value-dependent,
  ArrayType(TypeClass tc, QualType et, QualType can,
            ArraySizeModifier sm, unsigned tq,
            bool ContainsUnexpandedParameterPack)
    : Type(tc, can, et->isDependentType() || tc == DependentSizedArray,
           et->isInstantiationDependentType() || tc == DependentSizedArray,
           (tc == VariableArray || et->isVariablyModifiedType()),
           ContainsUnexpandedParameterPack),
      ElementType(et) {
    ArrayTypeBits.IndexTypeQuals = tq;
    ArrayTypeBits.SizeModifier = sm;
  }

  friend class ASTContext;  // ASTContext creates these.

public:
  QualType getElementType() const { return ElementType; }
  ArraySizeModifier getSizeModifier() const {
    return ArraySizeModifier(ArrayTypeBits.SizeModifier);
  }
  Qualifiers getIndexTypeQualifiers() const {
    return Qualifiers::fromCVRMask(getIndexTypeCVRQualifiers());
  }
  unsigned getIndexTypeCVRQualifiers() const {
    return ArrayTypeBits.IndexTypeQuals;
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == ConstantArray ||
           T->getTypeClass() == VariableArray ||
           T->getTypeClass() == IncompleteArray ||
           T->getTypeClass() == DependentSizedArray;
  }
};

/// ConstantArrayType - This class represents the canonical version of
/// C arrays with a specified constant size.  For example, the canonical
/// type for 'int A[4 + 4*100]' is a ConstantArrayType where the element
/// type is 'int' and the size is 404.
class ConstantArrayType : public ArrayType {
  llvm::APInt Size; // Allows us to unique the type.

  ConstantArrayType(QualType et, QualType can, const llvm::APInt &size,
                    ArraySizeModifier sm, unsigned tq)
    : ArrayType(ConstantArray, et, can, sm, tq,
                et->containsUnexpandedParameterPack()),
      Size(size) {}
protected:
  ConstantArrayType(TypeClass tc, QualType et, QualType can,
                    const llvm::APInt &size, ArraySizeModifier sm, unsigned tq)
    : ArrayType(tc, et, can, sm, tq, et->containsUnexpandedParameterPack()),
      Size(size) {}
  friend class ASTContext;  // ASTContext creates these.
public:
  const llvm::APInt &getSize() const { return Size; }
  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }


  /// \brief Determine the number of bits required to address a member of
  // an array with the given element type and number of elements.
  static unsigned getNumAddressingBits(ASTContext &Context,
                                       QualType ElementType,
                                       const llvm::APInt &NumElements);

  /// \brief Determine the maximum number of active bits that an array's size
  /// can require, which limits the maximum size of the array.
  static unsigned getMaxSizeBits(ASTContext &Context);

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getElementType(), getSize(),
            getSizeModifier(), getIndexTypeCVRQualifiers());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType ET,
                      const llvm::APInt &ArraySize, ArraySizeModifier SizeMod,
                      unsigned TypeQuals) {
    ID.AddPointer(ET.getAsOpaquePtr());
    ID.AddInteger(ArraySize.getZExtValue());
    ID.AddInteger(SizeMod);
    ID.AddInteger(TypeQuals);
  }
  static bool classof(const Type *T) {
    return T->getTypeClass() == ConstantArray;
  }
};

/// IncompleteArrayType - This class represents C arrays with an unspecified
/// size.  For example 'int A[]' has an IncompleteArrayType where the element
/// type is 'int' and the size is unspecified.
class IncompleteArrayType : public ArrayType {

  IncompleteArrayType(QualType et, QualType can,
                      ArraySizeModifier sm, unsigned tq)
    : ArrayType(IncompleteArray, et, can, sm, tq,
                et->containsUnexpandedParameterPack()) {}
  friend class ASTContext;  // ASTContext creates these.
public:
  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == IncompleteArray;
  }

  friend class StmtIteratorBase;

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getElementType(), getSizeModifier(),
            getIndexTypeCVRQualifiers());
  }

  static void Profile(llvm::FoldingSetNodeID &ID, QualType ET,
                      ArraySizeModifier SizeMod, unsigned TypeQuals) {
    ID.AddPointer(ET.getAsOpaquePtr());
    ID.AddInteger(SizeMod);
    ID.AddInteger(TypeQuals);
  }
};

/// VariableArrayType - This class represents C arrays with a specified size
/// which is not an integer-constant-expression.  For example, 'int s[x+foo()]'.
/// Since the size expression is an arbitrary expression, we store it as such.
///
/// Note: VariableArrayType's aren't uniqued (since the expressions aren't) and
/// should not be: two lexically equivalent variable array types could mean
/// different things, for example, these variables do not have the same type
/// dynamically:
///
/// void foo(int x) {
///   int Y[x];
///   ++x;
///   int Z[x];
/// }
///
class VariableArrayType : public ArrayType {
  /// SizeExpr - An assignment expression. VLA's are only permitted within
  /// a function block.
  Stmt *SizeExpr;
  /// Brackets - The left and right array brackets.
  SourceRange Brackets;

  VariableArrayType(QualType et, QualType can, Expr *e,
                    ArraySizeModifier sm, unsigned tq,
                    SourceRange brackets)
    : ArrayType(VariableArray, et, can, sm, tq,
                et->containsUnexpandedParameterPack()),
      SizeExpr((Stmt*) e), Brackets(brackets) {}
  friend class ASTContext;  // ASTContext creates these.

public:
  Expr *getSizeExpr() const {
    // We use C-style casts instead of cast<> here because we do not wish
    // to have a dependency of Type.h on Stmt.h/Expr.h.
    return (Expr*) SizeExpr;
  }
  SourceRange getBracketsRange() const { return Brackets; }
  SourceLocation getLBracketLoc() const { return Brackets.getBegin(); }
  SourceLocation getRBracketLoc() const { return Brackets.getEnd(); }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == VariableArray;
  }

  friend class StmtIteratorBase;

  void Profile(llvm::FoldingSetNodeID &ID) {
    llvm_unreachable("Cannot unique VariableArrayTypes.");
  }
};

/// DependentSizedArrayType - This type represents an array type in
/// C++ whose size is a value-dependent expression. For example:
///
/// \code
/// template<typename T, int Size>
/// class array {
///   T data[Size];
/// };
/// \endcode
///
/// For these types, we won't actually know what the array bound is
/// until template instantiation occurs, at which point this will
/// become either a ConstantArrayType or a VariableArrayType.
class DependentSizedArrayType : public ArrayType {
  const ASTContext &Context;

  /// \brief An assignment expression that will instantiate to the
  /// size of the array.
  ///
  /// The expression itself might be NULL, in which case the array
  /// type will have its size deduced from an initializer.
  Stmt *SizeExpr;

  /// Brackets - The left and right array brackets.
  SourceRange Brackets;

  DependentSizedArrayType(const ASTContext &Context, QualType et, QualType can,
                          Expr *e, ArraySizeModifier sm, unsigned tq,
                          SourceRange brackets);

  friend class ASTContext;  // ASTContext creates these.

public:
  Expr *getSizeExpr() const {
    // We use C-style casts instead of cast<> here because we do not wish
    // to have a dependency of Type.h on Stmt.h/Expr.h.
    return (Expr*) SizeExpr;
  }
  SourceRange getBracketsRange() const { return Brackets; }
  SourceLocation getLBracketLoc() const { return Brackets.getBegin(); }
  SourceLocation getRBracketLoc() const { return Brackets.getEnd(); }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == DependentSizedArray;
  }

  friend class StmtIteratorBase;


  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, Context, getElementType(),
            getSizeModifier(), getIndexTypeCVRQualifiers(), getSizeExpr());
  }

  static void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context,
                      QualType ET, ArraySizeModifier SizeMod,
                      unsigned TypeQuals, Expr *E);
};

/// DependentSizedExtVectorType - This type represent an extended vector type
/// where either the type or size is dependent. For example:
/// @code
/// template<typename T, int Size>
/// class vector {
///   typedef T __attribute__((ext_vector_type(Size))) type;
/// }
/// @endcode
class DependentSizedExtVectorType : public Type, public llvm::FoldingSetNode {
  const ASTContext &Context;
  Expr *SizeExpr;
  /// ElementType - The element type of the array.
  QualType ElementType;
  SourceLocation loc;

  DependentSizedExtVectorType(const ASTContext &Context, QualType ElementType,
                              QualType can, Expr *SizeExpr, SourceLocation loc);

  friend class ASTContext;

public:
  Expr *getSizeExpr() const { return SizeExpr; }
  QualType getElementType() const { return ElementType; }
  SourceLocation getAttributeLoc() const { return loc; }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == DependentSizedExtVector;
  }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, Context, getElementType(), getSizeExpr());
  }

  static void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context,
                      QualType ElementType, Expr *SizeExpr);
};


/// VectorType - GCC generic vector type. This type is created using
/// __attribute__((vector_size(n)), where "n" specifies the vector size in
/// bytes; or from an Altivec __vector or vector declaration.
/// Since the constructor takes the number of vector elements, the
/// client is responsible for converting the size into the number of elements.
class VectorType : public Type, public llvm::FoldingSetNode {
public:
  enum VectorKind {
    GenericVector,  // not a target-specific vector type
    AltiVecVector,  // is AltiVec vector
    AltiVecPixel,   // is AltiVec 'vector Pixel'
    AltiVecBool,    // is AltiVec 'vector bool ...'
    NeonVector,     // is ARM Neon vector
    NeonPolyVector  // is ARM Neon polynomial vector
  };
protected:
  /// ElementType - The element type of the vector.
  QualType ElementType;

  VectorType(QualType vecType, unsigned nElements, QualType canonType,
             VectorKind vecKind);

  VectorType(TypeClass tc, QualType vecType, unsigned nElements,
             QualType canonType, VectorKind vecKind);

  friend class ASTContext;  // ASTContext creates these.

public:

  QualType getElementType() const { return ElementType; }
  unsigned getNumElements() const { return VectorTypeBits.NumElements; }
  static bool isVectorSizeTooLarge(unsigned NumElements) {
    return NumElements > VectorTypeBitfields::MaxNumElements;
  }

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  VectorKind getVectorKind() const {
    return VectorKind(VectorTypeBits.VecKind);
  }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getElementType(), getNumElements(),
            getTypeClass(), getVectorKind());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType ElementType,
                      unsigned NumElements, TypeClass TypeClass,
                      VectorKind VecKind) {
    ID.AddPointer(ElementType.getAsOpaquePtr());
    ID.AddInteger(NumElements);
    ID.AddInteger(TypeClass);
    ID.AddInteger(VecKind);
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == Vector || T->getTypeClass() == ExtVector;
  }
};

/// ExtVectorType - Extended vector type. This type is created using
/// __attribute__((ext_vector_type(n)), where "n" is the number of elements.
/// Unlike vector_size, ext_vector_type is only allowed on typedef's. This
/// class enables syntactic extensions, like Vector Components for accessing
/// points, colors, and textures (modeled after OpenGL Shading Language).
class ExtVectorType : public VectorType {
  ExtVectorType(QualType vecType, unsigned nElements, QualType canonType) :
    VectorType(ExtVector, vecType, nElements, canonType, GenericVector) {}
  friend class ASTContext;  // ASTContext creates these.
public:
  static int getPointAccessorIdx(char c) {
    switch (c) {
    default: return -1;
    case 'x': case 'r': return 0;
    case 'y': case 'g': return 1;
    case 'z': case 'b': return 2;
    case 'w': case 'a': return 3;
    }
  }
  static int getNumericAccessorIdx(char c) {
    switch (c) {
      default: return -1;
      case '0': return 0;
      case '1': return 1;
      case '2': return 2;
      case '3': return 3;
      case '4': return 4;
      case '5': return 5;
      case '6': return 6;
      case '7': return 7;
      case '8': return 8;
      case '9': return 9;
      case 'A':
      case 'a': return 10;
      case 'B':
      case 'b': return 11;
      case 'C':
      case 'c': return 12;
      case 'D':
      case 'd': return 13;
      case 'E':
      case 'e': return 14;
      case 'F':
      case 'f': return 15;
    }
  }

  static int getAccessorIdx(char c) {
    if (int idx = getPointAccessorIdx(c)+1) return idx-1;
    return getNumericAccessorIdx(c);
  }

  bool isAccessorWithinNumElements(char c) const {
    if (int idx = getAccessorIdx(c)+1)
      return unsigned(idx-1) < getNumElements();
    return false;
  }
  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  static bool classof(const Type *T) {
    return T->getTypeClass() == ExtVector;
  }
};

/// FunctionType - C99 6.7.5.3 - Function Declarators.  This is the common base
/// class of FunctionNoProtoType and FunctionProtoType.
///
class FunctionType : public Type {
  // The type returned by the function.
  QualType ResultType;

 public:
  /// ExtInfo - A class which abstracts out some details necessary for
  /// making a call.
  ///
  /// It is not actually used directly for storing this information in
  /// a FunctionType, although FunctionType does currently use the
  /// same bit-pattern.
  ///
  // If you add a field (say Foo), other than the obvious places (both,
  // constructors, compile failures), what you need to update is
  // * Operator==
  // * getFoo
  // * withFoo
  // * functionType. Add Foo, getFoo.
  // * ASTContext::getFooType
  // * ASTContext::mergeFunctionTypes
  // * FunctionNoProtoType::Profile
  // * FunctionProtoType::Profile
  // * TypePrinter::PrintFunctionProto
  // * AST read and write
  // * Codegen
  class ExtInfo {
    // Feel free to rearrange or add bits, but if you go over 9,
    // you'll need to adjust both the Bits field below and
    // Type::FunctionTypeBitfields.

    //   |  CC  |noreturn|produces|regparm|
    //   |0 .. 3|   4    |    5   | 6 .. 8|
    //
    // regparm is either 0 (no regparm attribute) or the regparm value+1.
    enum { CallConvMask = 0xF };
    enum { NoReturnMask = 0x10 };
    enum { ProducesResultMask = 0x20 };
    enum { RegParmMask = ~(CallConvMask | NoReturnMask | ProducesResultMask),
           RegParmOffset = 6 }; // Assumed to be the last field

    uint16_t Bits;

    ExtInfo(unsigned Bits) : Bits(static_cast<uint16_t>(Bits)) {}

    friend class FunctionType;

   public:
    // Constructor with no defaults. Use this when you know that you
    // have all the elements (when reading an AST file for example).
    ExtInfo(bool noReturn, bool hasRegParm, unsigned regParm, CallingConv cc,
            bool producesResult) {
      assert((!hasRegParm || regParm < 7) && "Invalid regparm value");
      Bits = ((unsigned) cc) |
             (noReturn ? NoReturnMask : 0) |
             (producesResult ? ProducesResultMask : 0) |
             (hasRegParm ? ((regParm + 1) << RegParmOffset) : 0);
    }

    // Constructor with all defaults. Use when for example creating a
    // function know to use defaults.
    ExtInfo() : Bits(CC_C) { }

    // Constructor with just the calling convention, which is an important part
    // of the canonical type.
    ExtInfo(CallingConv CC) : Bits(CC) { }

    bool getNoReturn() const { return Bits & NoReturnMask; }
    bool getProducesResult() const { return Bits & ProducesResultMask; }
    bool getHasRegParm() const { return (Bits >> RegParmOffset) != 0; }
    unsigned getRegParm() const {
      unsigned RegParm = Bits >> RegParmOffset;
      if (RegParm > 0)
        --RegParm;
      return RegParm;
    }
    CallingConv getCC() const { return CallingConv(Bits & CallConvMask); }

    bool operator==(ExtInfo Other) const {
      return Bits == Other.Bits;
    }
    bool operator!=(ExtInfo Other) const {
      return Bits != Other.Bits;
    }

    // Note that we don't have setters. That is by design, use
    // the following with methods instead of mutating these objects.

    ExtInfo withNoReturn(bool noReturn) const {
      if (noReturn)
        return ExtInfo(Bits | NoReturnMask);
      else
        return ExtInfo(Bits & ~NoReturnMask);
    }

    ExtInfo withProducesResult(bool producesResult) const {
      if (producesResult)
        return ExtInfo(Bits | ProducesResultMask);
      else
        return ExtInfo(Bits & ~ProducesResultMask);
    }

    ExtInfo withRegParm(unsigned RegParm) const {
      assert(RegParm < 7 && "Invalid regparm value");
      return ExtInfo((Bits & ~RegParmMask) |
                     ((RegParm + 1) << RegParmOffset));
    }

    ExtInfo withCallingConv(CallingConv cc) const {
      return ExtInfo((Bits & ~CallConvMask) | (unsigned) cc);
    }

    void Profile(llvm::FoldingSetNodeID &ID) const {
      ID.AddInteger(Bits);
    }
  };

protected:
  FunctionType(TypeClass tc, QualType res,
               unsigned typeQuals, QualType Canonical, bool Dependent,
               bool InstantiationDependent,
               bool VariablyModified, bool ContainsUnexpandedParameterPack,
               ExtInfo Info)
    : Type(tc, Canonical, Dependent, InstantiationDependent, VariablyModified,
           ContainsUnexpandedParameterPack),
      ResultType(res) {
    FunctionTypeBits.ExtInfo = Info.Bits;
    FunctionTypeBits.TypeQuals = typeQuals;
  }
  unsigned getTypeQuals() const { return FunctionTypeBits.TypeQuals; }

public:
  QualType getReturnType() const { return ResultType; }

  bool getHasRegParm() const { return getExtInfo().getHasRegParm(); }
  unsigned getRegParmType() const { return getExtInfo().getRegParm(); }
  /// \brief Determine whether this function type includes the GNU noreturn
  /// attribute. The C++11 [[noreturn]] attribute does not affect the function
  /// type.
  bool getNoReturnAttr() const { return getExtInfo().getNoReturn(); }
  CallingConv getCallConv() const { return getExtInfo().getCC(); }
  ExtInfo getExtInfo() const { return ExtInfo(FunctionTypeBits.ExtInfo); }
  bool isConst() const { return getTypeQuals() & Qualifiers::Const; }
  bool isVolatile() const { return getTypeQuals() & Qualifiers::Volatile; }
  bool isRestrict() const { return getTypeQuals() & Qualifiers::Restrict; }

  /// \brief Determine the type of an expression that calls a function of
  /// this type.
  QualType getCallResultType(ASTContext &Context) const {
    return getReturnType().getNonLValueExprType(Context);
  }

  static StringRef getNameForCallConv(CallingConv CC);

  static bool classof(const Type *T) {
    return T->getTypeClass() == FunctionNoProto ||
           T->getTypeClass() == FunctionProto;
  }
};

/// FunctionNoProtoType - Represents a K&R-style 'int foo()' function, which has
/// no information available about its arguments.
class FunctionNoProtoType : public FunctionType, public llvm::FoldingSetNode {
  FunctionNoProtoType(QualType Result, QualType Canonical, ExtInfo Info)
    : FunctionType(FunctionNoProto, Result, 0, Canonical,
                   /*Dependent=*/false, /*InstantiationDependent=*/false,
                   Result->isVariablyModifiedType(),
                   /*ContainsUnexpandedParameterPack=*/false, Info) {}

  friend class ASTContext;  // ASTContext creates these.

public:
  // No additional state past what FunctionType provides.

  bool isSugared() const { return false; }
  QualType desugar() const { return QualType(this, 0); }

  void Profile(llvm::FoldingSetNodeID &ID) {
    Profile(ID, getReturnType(), getExtInfo());
  }
  static void Profile(llvm::FoldingSetNodeID &ID, QualType ResultType,
                      ExtInfo Info) {
    Info.Profile(ID);
    ID.AddPointer(ResultType.getAsOpaquePtr());
  }

  static bool classof(const Type *T) {
    return T->getTypeClass() == FunctionNoProto;
  }
};

/// FunctionProtoType - Represents a prototype with parameter type info, e.g.
/// 'int foo(int)' or 'int foo(void)'.  'void' is represented as having no
/// parameters, not as having a single void parameter. Such a type can have an
/// exception specification, but this specification is not part of the canonical
/// type.
class FunctionProtoType : public FunctionType, public llvm::FoldingSetNode {
public:
  /// ExtProtoInfo - Extra information about a function prototype.
  struct ExtProtoInfo {
    ExtProtoInfo()
        : Variadic(false), HasTrailingReturn(false), TypeQuals(0),
          ExceptionSpecType(EST_None), RefQualifier(RQ_None), NumExceptions(0),
          Exceptions(0), NoexceptExpr(0), ExceptionSpecDecl(0),
          ExceptionSpecTemplate(0), ConsumedParameters(0) {}

    ExtProtoInfo(CallingConv CC)
        : ExtInfo(CC), Variadic(false), HasTrailingReturn(false), TypeQuals(0),
          ExceptionSpecType(EST_None), RefQualifier(RQ_None), NumExceptions(0),
          Exceptions(0), NoexceptExpr(0), ExceptionSpecDecl(0),
          ExceptionSpecTemplate(0), ConsumedParameters(0) {}

    FunctionType::ExtInfo ExtInfo;
    bool Variadic : 1;
    bool HasTrailingReturn : 1;
    unsigned char TypeQuals;
    ExceptionSpecificationType ExceptionSpecType;
    RefQualifierKind RefQualifier;
    unsigned NumExceptions;
    const QualType *Exceptions;
    Expr *NoexceptExpr;
    FunctionDecl *ExceptionSpecDecl;
    FunctionDecl *ExceptionSpecTemplate;
    const bool *ConsumedParameters;
  };

private:
  /// \brief Determine whether there are any argument types that
  /// contain an unexpanded parameter pack.
  static bool containsAnyUnexpandedParameterPack(const QualType *ArgArray,
                                                 unsigned numArgs) {
    for (unsigned Idx = 0; Idx < numArgs; ++Idx)