path: root/include/clang/AST/Type.h

//===--- Type.h - C Language Family Type Representation ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and 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 "llvm/Support/Casting.h"
#include "llvm/ADT/FoldingSet.h"

using llvm::isa;
using llvm::cast;
using llvm::cast_or_null;
using llvm::dyn_cast;
using llvm::dyn_cast_or_null;

namespace clang {
  class ASTContext;
  class Type;
  class TypedefDecl;
  class TagDecl;
  class RecordDecl;
  class EnumDecl;
  class Expr;
  class SourceLocation;
  class PointerType;
  class ReferenceType;
  class VectorType;
  
/// QualType - For efficiency, we don't store CVR-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 three 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.
class QualType {
  uintptr_t ThePtr;
public:
  enum TQ {   // NOTE: These flags must be kept in sync with DeclSpec::TQ.
    Const    = 0x1,
    Restrict = 0x2,
    Volatile = 0x4,
    CVRFlags = Const|Restrict|Volatile
  };
  
  QualType() : ThePtr(0) {}
  
  QualType(Type *Ptr, unsigned Quals) {
    assert((Quals & ~CVRFlags) == 0 && "Invalid type qualifiers!");
    ThePtr = reinterpret_cast<uintptr_t>(Ptr);
    assert((ThePtr & CVRFlags) == 0 && "Type pointer not 8-byte aligned?");
    ThePtr |= Quals;
  }

  static QualType getFromOpaquePtr(void *Ptr) {
    QualType T;
    T.ThePtr = reinterpret_cast<uintptr_t>(Ptr);
    return T;
  }
  
  unsigned getQualifiers() const {
    return ThePtr & CVRFlags;
  }
  Type *getTypePtr() const {
    return reinterpret_cast<Type*>(ThePtr & ~CVRFlags);
  }
  
  void *getAsOpaquePtr() const {
    return reinterpret_cast<void*>(ThePtr);
  }
  
  Type &operator*() const {
    return *getTypePtr();
  }

  Type *operator->() const {
    return getTypePtr();
  }
  
  /// isNull - Return true if this QualType doesn't point to a type yet.
  bool isNull() const {
    return ThePtr == 0;
  }

  bool isConstQualified() const {
    return ThePtr & Const;
  }
  bool isVolatileQualified() const {
    return ThePtr & Volatile;
  }
  bool isRestrictQualified() const {
    return ThePtr & Restrict;
  }

  QualType getQualifiedType(unsigned TQs) const {
    return QualType(getTypePtr(), TQs);
  }
  
  QualType getUnqualifiedType() const {
    return QualType(getTypePtr(), 0);
  }
  
  /// operator==/!= - Indicate whether the specified types and qualifiers are
  /// identical.
  bool operator==(const QualType &RHS) const {
    return ThePtr == RHS.ThePtr;
  }
  bool operator!=(const QualType &RHS) const {
    return ThePtr != RHS.ThePtr;
  }
  std::string getAsString() const {
    std::string S;
    getAsStringInternal(S);
    return S;
  }
  void getAsStringInternal(std::string &Str) const;
  
  void dump(const char *s = 0) const;

  /// getCanonicalType - Return the canonical version of this type, with the
  /// appropriate type qualifiers on it.
  inline QualType getCanonicalType() const;
  
private:
};

} // 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<const ::clang::QualType> {
  typedef ::clang::Type* SimpleType;
  static SimpleType getSimplifiedValue(const ::clang::QualType &Val) {
    return Val.getTypePtr();
  }
};
template<> struct simplify_type< ::clang::QualType>
  : public simplify_type<const ::clang::QualType> {};
}

namespace clang {

/// 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
/// TypeNameType).  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 TypeNameType 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:
  enum TypeClass {
    Builtin, Complex, Pointer, Reference, Array, Vector, OCUVector,
    FunctionNoProto, FunctionProto,
    TypeName, Tagged
  };
private:
  QualType CanonicalType;

  /// TypeClass bitfield - Enum that specifies what subclass this belongs to.
  /// Note that this should stay at the end of the ivars for Type so that
  /// subclasses can pack their bitfields into the same word.
  TypeClass TC : 4;
protected:
  Type(TypeClass tc, QualType Canonical)
    : CanonicalType(Canonical.isNull() ? QualType(this,0) : Canonical), TC(tc){}
  virtual ~Type();
  friend class ASTContext;
public:
  TypeClass getTypeClass() const { return TC; }
  
  bool isCanonical() const { return CanonicalType.getTypePtr() == this; }

  /// Types are partitioned into 3 broad categories (C99 6.2.5p1): 
  /// object types, function types, and incomplete types.
  
  /// isObjectType - types that fully describe objects. An object is a region
  /// of memory that can be examined and stored into (H&S).
  bool isObjectType() const;

  /// isFunctionType - types that describe functions.
  bool isFunctionType() const;   

  /// 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.  
  bool isIncompleteType() const;
  
  /// Helper methods to distinguish type categories. All type predicates
  /// operate on the canonical type, ignoring typedefs.
  bool isIntegerType() const;     // C99 6.2.5p17 (int, char, bool, enum)
  
  /// Floating point categories.
  bool isRealFloatingType() const; // C99 6.2.5p10 (float, double, long double)
  bool isComplexType() const;      // C99 6.2.5p11 (complex)
  bool isFloatingType() const;     // C99 6.2.5p11 (real floating + complex)
  bool isRealType() const;         // C99 6.2.5p17 (real floating + integer)
  bool isArithmeticType() const;   // C99 6.2.5p18 (integer + floating)
  
  /// Vector types
  const VectorType *isVectorType() const; // GCC vector type.
  
  /// Derived types (C99 6.2.5p20). isFun