path: root/include/llvm/Constants.h

//===-- llvm/Constants.h - Constant class subclass definitions --*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// @file
/// This file contains the declarations for the subclasses of Constant, 
/// which represent the different flavors of constant values that live in LLVM.
/// Note that Constants are immutable (once created they never change) and are 
/// fully shared by structural equivalence.  This means that two structurally
/// equivalent constants will always have the same address.  Constant's are
/// created on demand as needed and never deleted: thus clients don't have to
/// worry about the lifetime of the objects.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CONSTANTS_H
#define LLVM_CONSTANTS_H

#include "llvm/Constant.h"
#include "llvm/OperandTraits.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/SmallVector.h"
#include <vector>

namespace llvm {

class ArrayType;
class IntegerType;
class StructType;
class UnionType;
class PointerType;
class VectorType;

template<class ConstantClass, class TypeClass, class ValType>
struct ConstantCreator;
template<class ConstantClass, class TypeClass>
struct ConvertConstantType;

//===----------------------------------------------------------------------===//
/// This is the shared class of boolean and integer constants. This class 
/// represents both boolean and integral constants.
/// @brief Class for constant integers.
class ConstantInt : public Constant {
  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
  ConstantInt(const ConstantInt &);      // DO NOT IMPLEMENT
  ConstantInt(const IntegerType *Ty, const APInt& V);
  APInt Val;
protected:
  // allocate space for exactly zero operands
  void *operator new(size_t s) {
    return User::operator new(s, 0);
  }
public:
  static ConstantInt *getTrue(LLVMContext &Context);
  static ConstantInt *getFalse(LLVMContext &Context);
  
  /// If Ty is a vector type, return a Constant with a splat of the given
  /// value. Otherwise return a ConstantInt for the given value.
  static Constant *get(const Type *Ty, uint64_t V, bool isSigned = false);
                              
  /// Return a ConstantInt with the specified integer value for the specified
  /// type. If the type is wider than 64 bits, the value will be zero-extended
  /// to fit the type, unless isSigned is true, in which case the value will
  /// be interpreted as a 64-bit signed integer and sign-extended to fit
  /// the type.
  /// @brief Get a ConstantInt for a specific value.
  static ConstantInt *get(const IntegerType *Ty, uint64_t V,
                          bool isSigned = false);

  /// Return a ConstantInt with the specified value for the specified type. The
  /// value V will be canonicalized to a an unsigned APInt. Accessing it with
  /// either getSExtValue() or getZExtValue() will yield a correctly sized and
  /// signed value for the type Ty.
  /// @brief Get a ConstantInt for a specific signed value.
  static ConstantInt *getSigned(const IntegerType *Ty, int64_t V);
  static Constant *getSigned(const Type *Ty, int64_t V);
  
  /// Return a ConstantInt with the specified value and an implied Type. The
  /// type is the integer type that corresponds to the bit width of the value.
  static ConstantInt *get(LLVMContext &Context, const APInt &V);

  /// Return a ConstantInt constructed from the string strStart with the given
  /// radix. 
  static ConstantInt *get(const IntegerType *Ty, StringRef Str,
                          uint8_t radix);
  
  /// If Ty is a vector type, return a Constant with a splat of the given
  /// value. Otherwise return a ConstantInt for the given value.
  static Constant *get(const Type* Ty, const APInt& V);
  
  /// Return the constant as an APInt value reference. This allows clients to
  /// obtain a copy of the value, with all its precision in tact.
  /// @brief Return the constant's value.
  inline const APInt &getValue() const {
    return Val;
  }
  
  /// getBitWidth - Return the bitwidth of this constant.
  unsigned getBitWidth() const { return Val.getBitWidth(); }

  /// Return the constant as a 64-bit unsigned integer value after it
  /// has been zero extended as appropriate for the type of this constant. Note
  /// that this method can assert if the value does not fit in 64 bits.
  /// @deprecated
  /// @brief Return the zero extended value.
  inline uint64_t getZExtValue() const {
    return Val.getZExtValue();
  }

  /// Return the constant as a 64-bit integer value after it has been sign
  /// extended as appropriate for the type of this constant. Note that
  /// this method can assert if the value does not fit in 64 bits.
  /// @deprecated
  /// @brief Return the sign extended value.
  inline int64_t getSExtValue() const {
    return Val.getSExtValue();
  }

  /// A helper method that can be used to determine if the constant contained 
  /// within is equal to a constant.  This only works for very small values, 
  /// because this is all that can be represented with all types.
  /// @brief Determine if this constant's value is same as an unsigned char.
  bool equalsInt(uint64_t V) const {
    return Val == V;
  }

  /// getType - Specialize the getType() method to always return an IntegerType,
  /// which reduces the amount of casting needed in parts of the compiler.
  ///
  inline const IntegerType *getType() const {
    return reinterpret_cast<const IntegerType*>(Value::getType());
  }

  /// This static method returns true if the type Ty is big enough to 
  /// represent the value V. This can be used to avoid having the get method 
  /// assert when V is larger than Ty can represent. Note that there are two
  /// versions of this method, one for unsigned and one for signed integers.
  /// Although ConstantInt canonicalizes everything to an unsigned integer, 
  /// the signed version avoids callers having to convert a signed quantity
  /// to the appropriate unsigned type before calling the method.
  /// @returns true if V is a valid value for type Ty
  /// @brief Determine if the value is in range for the given type.
  static bool isValueValidForType(const Type *Ty, uint64_t V);
  static bool isValueValidForType(const Type *Ty, int64_t V);

  /// This function will return true iff this constant represents the "null"
  /// value that would be returned by the getNullValue method.
  /// @returns true if this is the null integer value.
  /// @brief Determine if the value is null.
  virtual bool isNullValue() const { 
    return Val == 0; 
  }

  /// This is just a convenience method to make client code smaller for a
  /// common code. It also correctly performs the comparison without the
  /// potential for an assertion from getZExtValue().
  bool isZero() const {
    return Val == 0;
  }

  /// This is just a convenience method to make client code smaller for a 
  /// common case. It also correctly performs the comparison without the
  /// potential for an assertion from getZExtValue().
  /// @brief Determine if the value is