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Constants.h

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00001 //===-- llvm/Constants.h - Constant class subclass definitions --*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file contains the declarations for the subclasses of Constant, which
00011 // represent the different flavors of constant values that live in LLVM.  Note
00012 // that Constants are immutable (once created they never change) and are fully
00013 // shared by structural equivalence.  This means that two structurally
00014 // equivalent constants will always have the same address.  Constant's are
00015 // created on demand as needed and never deleted: thus clients don't have to
00016 // worry about the lifetime of the objects.
00017 //
00018 //===----------------------------------------------------------------------===//
00019 
00020 #ifndef LLVM_CONSTANTS_H
00021 #define LLVM_CONSTANTS_H
00022 
00023 #include "llvm/Constant.h"
00024 #include "llvm/Type.h"
00025 #include "llvm/Support/DataTypes.h"
00026 
00027 namespace llvm {
00028 
00029 class ArrayType;
00030 class StructType;
00031 class PointerType;
00032 class PackedType;
00033 
00034 template<class ConstantClass, class TypeClass, class ValType>
00035 struct ConstantCreator;
00036 template<class ConstantClass, class TypeClass>
00037 struct ConvertConstantType;
00038 
00039 //===----------------------------------------------------------------------===//
00040 /// ConstantIntegral - Shared superclass of boolean and integer constants.
00041 ///
00042 /// This class just defines some common interfaces to be implemented.
00043 ///
00044 class ConstantIntegral : public Constant {
00045 protected:
00046   union {
00047     int64_t  Signed;
00048     uint64_t Unsigned;
00049   } Val;
00050   ConstantIntegral(const Type *Ty, uint64_t V);
00051 public:
00052 
00053   /// getRawValue - return the underlying value of this constant as a 64-bit
00054   /// unsigned integer value.
00055   ///
00056   inline uint64_t getRawValue() const { return Val.Unsigned; }
00057 
00058   /// isNullValue - Return true if this is the value that would be returned by
00059   /// getNullValue.
00060   ///
00061   virtual bool isNullValue() const = 0;
00062 
00063   /// isMaxValue - Return true if this is the largest value that may be
00064   /// represented by this type.
00065   ///
00066   virtual bool isMaxValue() const = 0;
00067 
00068   /// isMinValue - Return true if this is the smallest value that may be
00069   /// represented by this type.
00070   ///
00071   virtual bool isMinValue() const = 0;
00072 
00073   /// isAllOnesValue - Return true if every bit in this constant is set to true.
00074   ///
00075   virtual bool isAllOnesValue() const = 0;
00076 
00077   /// Static constructor to get the maximum/minimum/allones constant of
00078   /// specified (integral) type...
00079   ///
00080   static ConstantIntegral *getMaxValue(const Type *Ty);
00081   static ConstantIntegral *getMinValue(const Type *Ty);
00082   static ConstantIntegral *getAllOnesValue(const Type *Ty);
00083 
00084   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00085   static inline bool classof(const ConstantIntegral *) { return true; }
00086   static bool classof(const Value *V) {
00087     return V->getValueType() == SimpleConstantVal &&
00088            V->getType()->isIntegral();
00089   }
00090 };
00091 
00092 
00093 //===----------------------------------------------------------------------===//
00094 /// ConstantBool - Boolean Values
00095 ///
00096 class ConstantBool : public ConstantIntegral {
00097   ConstantBool(bool V);
00098 public:
00099   static ConstantBool *True, *False;  // The True & False values
00100 
00101   /// get() - Static factory methods - Return objects of the specified value
00102   static ConstantBool *get(bool Value) { return Value ? True : False; }
00103   static ConstantBool *get(const Type *Ty, bool Value) { return get(Value); }
00104 
00105   /// inverted - Return the opposite value of the current value.
00106   inline ConstantBool *inverted() const { return (this==True) ? False : True; }
00107 
00108   /// getValue - return the boolean value of this constant.
00109   ///
00110   inline bool getValue() const { return static_cast<bool>(getRawValue()); }
00111 
00112   /// isNullValue - Return true if this is the value that would be returned by
00113   /// getNullValue.
00114   ///
00115   virtual bool isNullValue() const { return this == False; }
00116   virtual bool isMaxValue() const { return this == True; }
00117   virtual bool isMinValue() const { return this == False; }
00118   virtual bool isAllOnesValue() const { return this == True; }
00119 
00120   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00121   static inline bool classof(const ConstantBool *) { return true; }
00122   static bool classof(const Value *V) {
00123     return (V == True) | (V == False);
00124   }
00125 };
00126 
00127 
00128 //===----------------------------------------------------------------------===//
00129 /// ConstantInt - Superclass of ConstantSInt & ConstantUInt, to make dealing
00130 /// with integral constants easier.
00131 ///
00132 class ConstantInt : public ConstantIntegral {
00133 protected:
00134   ConstantInt(const ConstantInt &);      // DO NOT IMPLEMENT
00135   ConstantInt(const Type *Ty, uint64_t V);
00136 public:
00137   /// equalsInt - Provide a helper method that can be used to determine if the
00138   /// constant contained within is equal to a constant.  This only works for
00139   /// very small values, because this is all that can be represented with all
00140   /// types.
00141   ///
00142   bool equalsInt(unsigned char V) const {
00143     assert(V <= 127 &&
00144            "equalsInt: Can only be used with very small positive constants!");
00145     return Val.Unsigned == V;
00146   }
00147 
00148   /// ConstantInt::get static method: return a ConstantInt with the specified
00149   /// value.  as above, we work only with very small values here.
00150   ///
00151   static ConstantInt *get(const Type *Ty, unsigned char V);
00152 
00153   /// isNullValue - Return true if this is the value that would be returned by
00154   /// getNullValue.
00155   virtual bool isNullValue() const { return Val.Unsigned == 0; }
00156   virtual bool isMaxValue() const = 0;
00157   virtual bool isMinValue() const = 0;
00158 
00159   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00160   static inline bool classof(const ConstantInt *) { return true; }
00161   static bool classof(const Value *V) {
00162     return V->getValueType() == SimpleConstantVal &&
00163            V->getType()->isInteger();
00164   }
00165 };
00166 
00167 
00168 //===----------------------------------------------------------------------===//
00169 /// ConstantSInt - Signed Integer Values [sbyte, short, int, long]
00170 ///
00171 class ConstantSInt : public ConstantInt {
00172   ConstantSInt(const ConstantSInt &);      // DO NOT IMPLEMENT
00173   friend struct ConstantCreator<ConstantSInt, Type, int64_t>;
00174 
00175 protected:
00176   ConstantSInt(const Type *Ty, int64_t V);
00177 public:
00178   /// get() - Static factory methods - Return objects of the specified value
00179   ///
00180   static ConstantSInt *get(const Type *Ty, int64_t V);
00181 
00182   /// isValueValidForType - return true if Ty is big enough to represent V.
00183   ///
00184   static bool isValueValidForType(const Type *Ty, int64_t V);
00185 
00186   /// getValue - return the underlying value of this constant.
00187   ///
00188   inline int64_t getValue() const { return Val.Signed; }
00189 
00190   virtual bool isAllOnesValue() const { return getValue() == -1; }
00191 
00192   /// isMaxValue - Return true if this is the largest value that may be
00193   /// represented by this type.
00194   ///
00195   virtual bool isMaxValue() const {
00196     int64_t V = getValue();
00197     if (V < 0) return false;    // Be careful about wrap-around on 'long's
00198     ++V;
00199     return !isValueValidForType(getType(), V) || V < 0;
00200   }
00201 
00202   /// isMinValue - Return true if this is the smallest value that may be
00203   /// represented by this type.
00204   ///
00205   virtual bool isMinValue() const {
00206     int64_t V = getValue();
00207     if (V > 0) return false;    // Be careful about wrap-around on 'long's
00208     --V;
00209     return !isValueValidForType(getType(), V) || V > 0;
00210   }
00211 
00212   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00213   ///
00214   static inline bool classof(const ConstantSInt *) { return true; }
00215   static bool classof(const Value *V) {
00216     return V->getValueType() == SimpleConstantVal &&
00217            V->getType()->isSigned();
00218   }
00219 };
00220 
00221 //===----------------------------------------------------------------------===//
00222 /// ConstantUInt - Unsigned Integer Values [ubyte, ushort, uint, ulong]
00223 ///
00224 class ConstantUInt : public ConstantInt {
00225   ConstantUInt(const ConstantUInt &);      // DO NOT IMPLEMENT
00226   friend struct ConstantCreator<ConstantUInt, Type, uint64_t>;
00227 protected:
00228   ConstantUInt(const Type *Ty, uint64_t V);
00229 public:
00230   /// get() - Static factory methods - Return objects of the specified value
00231   ///
00232   static ConstantUInt *get(const Type *Ty, uint64_t V);
00233 
00234   /// isValueValidForType - return true if Ty is big enough to represent V.
00235   ///
00236   static bool isValueValidForType(const Type *Ty, uint64_t V);
00237 
00238   /// getValue - return the underlying value of this constant.
00239   ///
00240   inline uint64_t getValue() const { return Val.Unsigned; }
00241 
00242   /// isMaxValue - Return true if this is the largest value that may be
00243   /// represented by this type.
00244   ///
00245   virtual bool isAllOnesValue() const;
00246   virtual bool isMaxValue() const { return isAllOnesValue(); }
00247   virtual bool isMinValue() const { return getValue() == 0; }
00248 
00249   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00250   static inline bool classof(const ConstantUInt *) { return true; }
00251   static bool classof(const Value *V) {
00252     return V->getValueType() == SimpleConstantVal &&
00253            V->getType()->isUnsigned();
00254   }
00255 };
00256 
00257 
00258 //===----------------------------------------------------------------------===//
00259 /// ConstantFP - Floating Point Values [float, double]
00260 ///
00261 class ConstantFP : public Constant {
00262   double Val;
00263   friend struct ConstantCreator<ConstantFP, Type, uint64_t>;
00264   friend struct ConstantCreator<ConstantFP, Type, uint32_t>;
00265   ConstantFP(const ConstantFP &);      // DO NOT IMPLEMENT
00266 protected:
00267   ConstantFP(const Type *Ty, double V);
00268 public:
00269   /// get() - Static factory methods - Return objects of the specified value
00270   static ConstantFP *get(const Type *Ty, double V);
00271 
00272   /// isValueValidForType - return true if Ty is big enough to represent V.
00273   static bool isValueValidForType(const Type *Ty, double V);
00274   inline double getValue() const { return Val; }
00275 
00276   /// isNullValue - Return true if this is the value that would be returned by
00277   /// getNullValue.  Don't depend on == for doubles to tell us it's zero, it
00278   /// considers -0.0 to be null as well as 0.0.  :(
00279   virtual bool isNullValue() const {
00280     union {
00281       double V;
00282       uint64_t I;
00283     } T;
00284     T.V = Val;
00285     return T.I == 0;
00286   }
00287 
00288   /// isExactlyValue - We don't rely on operator== working on double values, as
00289   /// it returns true for things that are clearly not equal, like -0.0 and 0.0.
00290   /// As such, this method can be used to do an exact bit-for-bit comparison of
00291   /// two floating point values.
00292   bool isExactlyValue(double V) const {
00293     union {
00294       double V;
00295       uint64_t I;
00296     } T1;
00297     T1.V = Val;
00298     union {
00299       double V;
00300       uint64_t I;
00301     } T2;
00302     T2.V = V;
00303     return T1.I == T2.I;
00304   }
00305 
00306   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00307   static inline bool classof(const ConstantFP *) { return true; }
00308   static bool classof(const Value *V) {
00309     return V->getValueType() == SimpleConstantVal &&
00310            V->getType()->isFloatingPoint();
00311   }
00312 };
00313 
00314 //===----------------------------------------------------------------------===//
00315 /// ConstantAggregateZero - All zero aggregate value
00316 ///
00317 class ConstantAggregateZero : public Constant {
00318   friend struct ConstantCreator<ConstantAggregateZero, Type, char>;
00319   ConstantAggregateZero(const ConstantAggregateZero &);      // DO NOT IMPLEMENT
00320 protected:
00321   ConstantAggregateZero(const Type *Ty)
00322     : Constant(Ty, ConstantAggregateZeroVal) {}
00323 public:
00324   /// get() - static factory method for creating a null aggregate.  It is
00325   /// illegal to call this method with a non-aggregate type.
00326   static Constant *get(const Type *Ty);
00327 
00328   /// isNullValue - Return true if this is the value that would be returned by
00329   /// getNullValue.
00330   virtual bool isNullValue() const { return true; }
00331 
00332   virtual void destroyConstant();
00333   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
00334                                            bool DisableChecking = false);
00335 
00336   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00337   ///
00338   static bool classof(const ConstantAggregateZero *) { return true; }
00339   static bool classof(const Value *V) {
00340     return V->getValueType() == ConstantAggregateZeroVal;
00341   }
00342 };
00343 
00344 
00345 //===----------------------------------------------------------------------===//
00346 /// ConstantArray - Constant Array Declarations
00347 ///
00348 class ConstantArray : public Constant {
00349   friend struct ConstantCreator<ConstantArray, ArrayType,
00350                                     std::vector<Constant*> >;
00351   ConstantArray(const ConstantArray &);      // DO NOT IMPLEMENT
00352 protected:
00353   ConstantArray(const ArrayType *T, const std::vector<Constant*> &Val);
00354 public:
00355   /// get() - Static factory methods - Return objects of the specified value
00356   static Constant *get(const ArrayType *T, const std::vector<Constant*> &);
00357   static Constant *get(const std::string &Initializer);
00358   
00359   /// getType - Specialize the getType() method to always return an ArrayType,
00360   /// which reduces the amount of casting needed in parts of the compiler.
00361   ///
00362   inline const ArrayType *getType() const {
00363     return reinterpret_cast<const ArrayType*>(Value::getType());
00364   }
00365 
00366   /// isString - This method returns true if the array is an array of sbyte or
00367   /// ubyte, and if the elements of the array are all ConstantInt's.
00368   bool isString() const;
00369 
00370   /// getAsString - If this array is isString(), then this method converts the
00371   /// array to an std::string and returns it.  Otherwise, it asserts out.
00372   ///
00373   std::string getAsString() const;
00374 
00375   /// isNullValue - Return true if this is the value that would be returned by
00376   /// getNullValue.  This always returns false because zero arrays are always
00377   /// created as ConstantAggregateZero objects.
00378   virtual bool isNullValue() const { return false; }
00379 
00380   virtual void destroyConstant();
00381   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
00382                                            bool DisableChecking = false);
00383 
00384   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00385   static inline bool classof(const ConstantArray *) { return true; }
00386   static bool classof(const Value *V) {
00387     return V->getValueType() == SimpleConstantVal &&
00388            V->getType()->getTypeID() == Type::ArrayTyID;
00389   }
00390 };
00391 
00392 
00393 //===----------------------------------------------------------------------===//
00394 // ConstantStruct - Constant Struct Declarations
00395 //
00396 class ConstantStruct : public Constant {
00397   friend struct ConstantCreator<ConstantStruct, StructType,
00398                                     std::vector<Constant*> >;
00399   ConstantStruct(const ConstantStruct &);      // DO NOT IMPLEMENT
00400 protected:
00401   ConstantStruct(const StructType *T, const std::vector<Constant*> &Val);
00402 public:
00403   /// get() - Static factory methods - Return objects of the specified value
00404   ///
00405   static Constant *get(const StructType *T, const std::vector<Constant*> &V);
00406   static Constant *get(const std::vector<Constant*> &V);
00407 
00408   /// getType() specialization - Reduce amount of casting...
00409   ///
00410   inline const StructType *getType() const {
00411     return reinterpret_cast<const StructType*>(Value::getType());
00412   }
00413 
00414   /// isNullValue - Return true if this is the value that would be returned by
00415   /// getNullValue.  This always returns false because zero structs are always
00416   /// created as ConstantAggregateZero objects.
00417   virtual bool isNullValue() const {
00418     return false;
00419   }
00420 
00421   virtual void destroyConstant();
00422   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
00423                                            bool DisableChecking = false);
00424   
00425   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00426   static inline bool classof(const ConstantStruct *) { return true; }
00427   static bool classof(const Value *V) {
00428     return V->getValueType() == SimpleConstantVal &&
00429            V->getType()->getTypeID() == Type::StructTyID;
00430   }
00431 };
00432 
00433 //===----------------------------------------------------------------------===//
00434 /// ConstantPacked - Constant Packed Declarations
00435 ///
00436 class ConstantPacked : public Constant {
00437   friend struct ConstantCreator<ConstantPacked, PackedType,
00438                                     std::vector<Constant*> >;
00439   ConstantPacked(const ConstantPacked &);      // DO NOT IMPLEMENT
00440 protected:
00441   ConstantPacked(const PackedType *T, const std::vector<Constant*> &Val);
00442 public:
00443   /// get() - Static factory methods - Return objects of the specified value
00444   static Constant *get(const PackedType *T, const std::vector<Constant*> &);
00445   static Constant *get(const std::vector<Constant*> &V);
00446   
00447   /// getType - Specialize the getType() method to always return an PackedType,
00448   /// which reduces the amount of casting needed in parts of the compiler.
00449   ///
00450   inline const PackedType *getType() const {
00451     return reinterpret_cast<const PackedType*>(Value::getType());
00452   }
00453 
00454   /// isNullValue - Return true if this is the value that would be returned by
00455   /// getNullValue.  This always returns false because zero arrays are always
00456   /// created as ConstantAggregateZero objects.
00457   virtual bool isNullValue() const { return false; }
00458 
00459   virtual void destroyConstant();
00460   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
00461                                            bool DisableChecking = false);
00462 
00463   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00464   static inline bool classof(const ConstantPacked *) { return true; }
00465   static bool classof(const Value *V) {
00466     return V->getValueType() == SimpleConstantVal &&
00467            V->getType()->getTypeID() == Type::PackedTyID;
00468   }
00469 };
00470 
00471 //===----------------------------------------------------------------------===//
00472 /// ConstantPointerNull - a constant pointer value that points to null
00473 ///
00474 class ConstantPointerNull : public Constant {
00475   friend struct ConstantCreator<ConstantPointerNull, PointerType, char>;
00476   ConstantPointerNull(const ConstantPointerNull &);      // DO NOT IMPLEMENT
00477 protected:
00478   ConstantPointerNull(const PointerType *T)
00479     : Constant(reinterpret_cast<const Type*>(T)) {}
00480 
00481 public:
00482 
00483   /// get() - Static factory methods - Return objects of the specified value
00484   static ConstantPointerNull *get(const PointerType *T);
00485 
00486   /// isNullValue - Return true if this is the value that would be returned by
00487   /// getNullValue.
00488   virtual bool isNullValue() const { return true; }
00489 
00490   virtual void destroyConstant();
00491 
00492   /// getType - Specialize the getType() method to always return an PointerType,
00493   /// which reduces the amount of casting needed in parts of the compiler.
00494   ///
00495   inline const PointerType *getType() const {
00496     return reinterpret_cast<const PointerType*>(Value::getType());
00497   }
00498 
00499   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00500   static inline bool classof(const ConstantPointerNull *) { return true; }
00501   static bool classof(const Value *V) {
00502     return V->getValueType() == SimpleConstantVal &&
00503            isa<PointerType>(V->getType());
00504   }
00505 };
00506 
00507 
00508 /// ConstantExpr - a constant value that is initialized with an expression using
00509 /// other constant values.  This is only used to represent values that cannot be
00510 /// evaluated at compile-time (e.g., something derived from an address) because
00511 /// it does not have a mechanism to store the actual value.  Use the appropriate
00512 /// Constant subclass above for known constants.
00513 ///
00514 class ConstantExpr : public Constant {
00515   unsigned iType;      // Operation type (an Instruction opcode)
00516   friend struct ConstantCreator<ConstantExpr,Type,
00517                             std::pair<unsigned, std::vector<Constant*> > >;
00518   friend struct ConvertConstantType<ConstantExpr, Type>;
00519   
00520 protected:
00521   // Cast creation ctor
00522   ConstantExpr(unsigned Opcode, Constant *C, const Type *Ty);
00523   // Binary/Shift instruction creation ctor
00524   ConstantExpr(unsigned Opcode, Constant *C1, Constant *C2);
00525   // Select instruction creation ctor
00526   ConstantExpr(Constant *C, Constant *V1, Constant *V2);
00527   // GEP instruction creation ctor
00528   ConstantExpr(Constant *C, const std::vector<Constant*> &IdxList,
00529                const Type *DestTy);
00530 
00531   // These private methods are used by the type resolution code to create
00532   // ConstantExprs in intermediate forms.
00533   static Constant *getTy(const Type *Ty, unsigned Opcode,
00534                          Constant *C1, Constant *C2);
00535   static Constant *getShiftTy(const Type *Ty,
00536                               unsigned Opcode, Constant *C1, Constant *C2);
00537   static Constant *getSelectTy(const Type *Ty,
00538                                Constant *C1, Constant *C2, Constant *C3);
00539   static Constant *getGetElementPtrTy(const Type *Ty, Constant *C,
00540                                       const std::vector<Value*> &IdxList);
00541   
00542 public:
00543   // Static methods to construct a ConstantExpr of different kinds.  Note that
00544   // these methods may return a object that is not an instance of the
00545   // ConstantExpr class, because they will attempt to fold the constant
00546   // expression into something simpler if possible.
00547   
00548   /// Cast constant expr
00549   ///
00550   static Constant *getCast(Constant *C, const Type *Ty);
00551   static Constant *getSignExtend(Constant *C, const Type *Ty);
00552   static Constant *getZeroExtend(Constant *C, const Type *Ty);
00553 
00554   /// Select constant expr
00555   ///
00556   static Constant *getSelect(Constant *C, Constant *V1, Constant *V2) {
00557     return getSelectTy(V1->getType(), C, V1, V2);
00558   }
00559 
00560   /// getSizeOf constant expr - computes the size of a type in a target
00561   /// independent way (Note: the return type is UInt but the object is not
00562   /// necessarily a ConstantUInt).
00563   ///
00564   static Constant *getSizeOf(const Type *Ty);
00565 
00566   /// ConstantExpr::get - Return a binary or shift operator constant expression,
00567   /// folding if possible.
00568   ///
00569   static Constant *get(unsigned Opcode, Constant *C1, Constant *C2);
00570 
00571   /// ConstantExpr::get* - Return some common constants without having to
00572   /// specify the full Instruction::OPCODE identifier.
00573   ///
00574   static Constant *getNeg(Constant *C);
00575   static Constant *getNot(Constant *C);
00576   static Constant *getAdd(Constant *C1, Constant *C2);
00577   static Constant *getSub(Constant *C1, Constant *C2);
00578   static Constant *getMul(Constant *C1, Constant *C2);
00579   static Constant *getDiv(Constant *C1, Constant *C2);
00580   static Constant *getRem(Constant *C1, Constant *C2);
00581   static Constant *getAnd(Constant *C1, Constant *C2);
00582   static Constant *getOr(Constant *C1, Constant *C2);
00583   static Constant *getXor(Constant *C1, Constant *C2);
00584   static Constant *getSetEQ(Constant *C1, Constant *C2);
00585   static Constant *getSetNE(Constant *C1, Constant *C2);
00586   static Constant *getSetLT(Constant *C1, Constant *C2);
00587   static Constant *getSetGT(Constant *C1, Constant *C2);
00588   static Constant *getSetLE(Constant *C1, Constant *C2);
00589   static Constant *getSetGE(Constant *C1, Constant *C2);
00590   static Constant *getShl(Constant *C1, Constant *C2);
00591   static Constant *getShr(Constant *C1, Constant *C2);
00592 
00593   static Constant *getUShr(Constant *C1, Constant *C2); // unsigned shr
00594   static Constant *getSShr(Constant *C1, Constant *C2); // signed shr
00595 
00596   /// Getelementptr form.  std::vector<Value*> is only accepted for convenience:
00597   /// all elements must be Constant's.
00598   ///
00599   static Constant *getGetElementPtr(Constant *C,
00600                                     const std::vector<Constant*> &IdxList);
00601   static Constant *getGetElementPtr(Constant *C,
00602                                     const std::vector<Value*> &IdxList);
00603   
00604   /// isNullValue - Return true if this is the value that would be returned by
00605   /// getNullValue.
00606   virtual bool isNullValue() const { return false; }
00607   
00608   /// getOpcode - Return the opcode at the root of this constant expression
00609   unsigned getOpcode() const { return iType; }
00610 
00611   /// getOpcodeName - Return a string representation for an opcode.
00612   const char *getOpcodeName() const;
00613   
00614   virtual void destroyConstant();
00615   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To,
00616                                            bool DisableChecking = false);
00617     
00618   /// Override methods to provide more type information...
00619   inline Constant *getOperand(unsigned i) { 
00620     return cast<Constant>(User::getOperand(i));
00621   }
00622   inline Constant *getOperand(unsigned i) const {
00623     return const_cast<Constant*>(cast<Constant>(User::getOperand(i)));
00624   }
00625   
00626 
00627   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00628   static inline bool classof(const ConstantExpr *) { return true; }
00629   static inline bool classof(const Value *V) {
00630     return V->getValueType() == ConstantExprVal;
00631   }
00632 };
00633 
00634 
00635 //===----------------------------------------------------------------------===//
00636 /// UndefValue - 'undef' values are things that do not have specified contents.
00637 /// These are used for a variety of purposes, including global variable
00638 /// initializers and operands to instructions.  'undef' values can occur with
00639 /// any type.
00640 ///
00641 class UndefValue : public Constant {
00642   friend struct ConstantCreator<UndefValue, Type, char>;
00643   UndefValue(const UndefValue &);      // DO NOT IMPLEMENT
00644 protected:
00645   UndefValue(const Type *T) : Constant(T, UndefValueVal) {}
00646 public:
00647   /// get() - Static factory methods - Return an 'undef' object of the specified
00648   /// type.
00649   ///
00650   static UndefValue *get(const Type *T);
00651 
00652   /// isNullValue - Return true if this is the value that would be returned by
00653   /// getNullValue.
00654   virtual bool isNullValue() const { return false; }
00655 
00656   virtual void destroyConstant();
00657 
00658   /// Methods for support type inquiry through isa, cast, and dyn_cast:
00659   static inline bool classof(const UndefValue *) { return true; }
00660   static bool classof(const Value *V) {
00661     return V->getValueType() == UndefValueVal;
00662   }
00663 };
00664 
00665 } // End llvm namespace
00666 
00667 #endif