path: root/include/llvm/DerivedTypes.h

//===-- llvm/DerivedTypes.h - Classes for handling data types ---*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declarations of classes that represent "derived
// types".  These are things like "arrays of x" or "structure of x, y, z" or
// "method returning x taking (y,z) as parameters", etc...
//
// The implementations of these classes live in the Type.cpp file.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_DERIVED_TYPES_H
#define LLVM_DERIVED_TYPES_H

#include "llvm/Type.h"

namespace llvm {

class Value;
template<class ValType, class TypeClass> class TypeMap;
class FunctionValType;
class ArrayValType;
class StructValType;
class UnionValType;
class PointerValType;
class VectorValType;
class IntegerValType;
class APInt;
class LLVMContext;

class DerivedType : public Type {
  friend class Type;

protected:
  explicit DerivedType(LLVMContext &C, TypeID id) : Type(C, id) {}

  /// notifyUsesThatTypeBecameConcrete - Notify AbstractTypeUsers of this type
  /// that the current type has transitioned from being abstract to being
  /// concrete.
  ///
  void notifyUsesThatTypeBecameConcrete();

  /// dropAllTypeUses - When this (abstract) type is resolved to be equal to
  /// another (more concrete) type, we must eliminate all references to other
  /// types, to avoid some circular reference problems.
  ///
  void dropAllTypeUses();

  /// unlockedRefineAbstractTypeTo - Internal version of refineAbstractTypeTo
  /// that performs no locking.  Only used for internal recursion.
  void unlockedRefineAbstractTypeTo(const Type *NewType);
  
public:

  //===--------------------------------------------------------------------===//
  // Abstract Type handling methods - These types have special lifetimes, which
  // are managed by (add|remove)AbstractTypeUser. See comments in
  // AbstractTypeUser.h for more information.

  /// refineAbstractTypeTo - This function is used to when it is discovered that
  /// the 'this' abstract type is actually equivalent to the NewType specified.
  /// This causes all users of 'this' to switch to reference the more concrete
  /// type NewType and for 'this' to be deleted.
  ///
  void refineAbstractTypeTo(const Type *NewType);

  void dump() const { Type::dump(); }

  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const DerivedType *) { return true; }
  static inline bool classof(const Type *T) {
    return T->isDerivedType();
  }
};

/// Class to represent integer types. Note that this class is also used to
/// represent the built-in integer types: Int1Ty, Int8Ty, Int16Ty, Int32Ty and
/// Int64Ty.
/// @brief Integer representation type
class IntegerType : public DerivedType {
  friend class LLVMContextImpl;
  
protected:
  explicit IntegerType(LLVMContext &C, unsigned NumBits) : 
      DerivedType(C, IntegerTyID) {
    setSubclassData(NumBits);
  }
  friend class TypeMap<IntegerValType, IntegerType>;
public:
  /// This enum is just used to hold constants we need for IntegerType.
  enum {
    MIN_INT_BITS = 1,        ///< Minimum number of bits that can be specified
    MAX_INT_BITS = (1<<23)-1 ///< Maximum number of bits that can be specified
      ///< Note that bit width is stored in the Type classes SubclassData field
      ///< which has 23 bits. This yields a maximum bit width of 8,388,607 bits.
  };

  /// This static method is the primary way of constructing an IntegerType.
  /// If an IntegerType with the same NumBits value was previously instantiated,
  /// that instance will be returned. Otherwise a new one will be created. Only
  /// one instance with a given NumBits value is ever created.
  /// @brief Get or create an IntegerType instance.
  static const IntegerType* get(LLVMContext &C, unsigned NumBits);

  /// @brief Get the number of bits in this IntegerType
  unsigned getBitWidth() const { return getSubclassData(); }

  /// getBitMask - Return a bitmask with ones set for all of the bits
  /// that can be set by an unsigned version of this type.  This is 0xFF for
  /// i8, 0xFFFF for i16, etc.
  uint64_t getBitMask() const {
    return ~uint64_t(0UL) >> (64-getBitWidth());
  }

  /// getSignBit - Return a uint64_t with just the most significant bit set (the
  /// sign bit, if the value is treated as a signed number).
  uint64_t getSignBit() const {
    return 1ULL << (getBitWidth()-1);
  }

  /// For example, this is 0xFF for an 8 bit integer, 0xFFFF for i16, etc.
  /// @returns a bit mask with ones set for all the bits of this type.
  /// @brief Get a bit mask for this type.
  APInt getMask() const;

  /// This method determines if the width of this IntegerType is a power-of-2
  /// in terms of 8 bit bytes.
  /// @returns true if this is a power-of-2 byte width.
  /// @brief Is this a power-of-2 byte-width IntegerType ?
  bool isPowerOf2ByteWidth() const;

  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const IntegerType *) { return true; }
  static inline bool classof(const Type *T) {
    return T->getTypeID() == IntegerTyID;
  }
};


/// FunctionType - Class to represent function types
///
class FunctionType : public DerivedType {
  friend class TypeMap<FunctionValType, FunctionType>;
  bool isVarArgs;

  FunctionType(const FunctionType &);                   // Do not implement
  const FunctionType &operator=(const FunctionType &);  // Do not implement
  FunctionType(const Type *Result, const std::vector<const Type*> &Params,
               bool IsVarArgs);

public:
  /// FunctionType::get - This static method is the primary way of constructing
  /// a FunctionType.
  ///
  static FunctionType *get(
    const Type *Result, ///< The result type
    const std::vector<const Type*> &Params, ///< The types of the parameters
    bool isVarArg  ///< Whether this is a variable argument length function
  );

  /// FunctionType::get - Create a FunctionType taking no parameters.
  ///
  static FunctionType *get(
    const Type *Result, ///< The result type
    bool isVarArg  ///< Whether this is a variable argument length function
  ) {
    return get(Result, std::vector<const Type *>(), isVarArg);
  }

  /// isValidReturnType - Return true if the specified type is valid as a return
  /// type.
  static bool isValidReturnType(const Type *RetTy);

  /// isValidArgumentType - Return true if the specified type is valid as an
  /// argument type.
  static bool isValidArgumentType(const Type *ArgTy);

  inline bool isVarArg() const { return isVarArgs; }
  inline const Type *getReturnType() const { return ContainedTys[0]; }

  typedef Type::subtype_iterator param_iterator;
  param_iterator param_begin() const { return ContainedTys + 1; }
  param_iterator param_end() const { return &ContainedTys[NumContainedTys]; }

  // Parameter type accessors...
  const Type *getParamType(unsigned i) const { return ContainedTys[i+1]; }

  /// getNumParams - Return the number of fixed parameters this function type
  /// requires.  This does not consider varargs.
  ///
  unsigned getNumParams() const { return NumContainedTys - 1; }

  // Implement the AbstractTypeUser interface.
  virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
  virtual void typeBecameConcrete(const DerivedType *AbsTy);

  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const FunctionType *) { return true; }
  static inline bool classof(const Type *T) {
    return T->getTypeID() == FunctionTyID;
  }
};


/// CompositeType - Common super class of ArrayType, StructType, PointerType
/// and VectorType
class CompositeType : public DerivedType {
protected:
  inline explicit CompositeType(LLVMContext &C, TypeID id) :
    DerivedType(C, id) { }
public:

  /// getTypeAtIndex - Given an index value into the type, return the type of
  /// the element.
  ///
  virtual const Type *getTypeAtIndex(const Value *V) const = 0;
  virtual const Type *getTypeAtIndex(unsigned Idx) const = 0;
  virtual bool indexValid(const Value *V) const = 0;
  virtual bool indexValid(unsigned Idx) const = 0;

  // Methods for support type inquiry through isa, cast, and dyn_cast:
  static inline bool classof(const CompositeType *) { return true; }
  static inline bool classof(const Type *T) {
    return T->getTypeID() ==