Type.h revision 26199059268a05739c84ebf465fcdbf7ded861df 
1//===-- llvm/Type.h - Classes for handling data types ------------*- C++ -*--=//
2//
3// This file contains the declaration of the Type class.  For more "Type" type
4// stuff, look in DerivedTypes.h.
5//
6// Note that instances of the Type class are immutable: once they are created,
7// they are never changed.  Also note that only one instance of a particular
8// type is ever created.  Thus seeing if two types are equal is a matter of
9// doing a trivial pointer comparison.
10//
11// Types, once allocated, are never free'd.
12//
13// Opaque types are simple derived types with no state.  There may be many
14// different Opaque type objects floating around, but two are only considered
15// identical if they are pointer equals of each other.  This allows us to have
16// two opaque types that end up resolving to different concrete types later.
17//
18// Opaque types are also kinda wierd and scary and different because they have
19// to keep a list of uses of the type.  When, through linking, parsing, or
20// bytecode reading, they become resolved, they need to find and update all
21// users of the unknown type, causing them to reference a new, more concrete
22// type.  Opaque types are deleted when their use list dwindles to zero users.
23//
24//===----------------------------------------------------------------------===//
25
26#ifndef LLVM_TYPE_H
27#define LLVM_TYPE_H
28
29#include "llvm/Value.h"
30#include "Support/GraphTraits.h"
31#include "Support/iterator"
32
33class DerivedType;
34class FunctionType;
35class ArrayType;
36class PointerType;
37class StructType;
38class OpaqueType;
39
40class Type : public Value {
41public:
42  ///===-------------------------------------------------------------------===//
43  /// Definitions of all of the base types for the Type system.  Based on this
44  /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
45  /// Note: If you add an element to this, you need to add an element to the
46  /// Type::getPrimitiveType function, or else things will break!
47  ///
48  enum PrimitiveID {
49    VoidTyID = 0  , BoolTyID,           //  0, 1: Basics...
50    UByteTyID     , SByteTyID,          //  2, 3: 8 bit types...
51    UShortTyID    , ShortTyID,          //  4, 5: 16 bit types...
52    UIntTyID      , IntTyID,            //  6, 7: 32 bit types...
53    ULongTyID     , LongTyID,           //  8, 9: 64 bit types...
54
55    FloatTyID     , DoubleTyID,         // 10,11: Floating point types...
56
57    TypeTyID,                           // 12   : Type definitions
58    LabelTyID     ,                     // 13   : Labels...
59
60    // Derived types... see DerivedTypes.h file...
61    // Make sure FirstDerivedTyID stays up to date!!!
62    FunctionTyID  , StructTyID,         // Functions... Structs...
63    ArrayTyID     , PointerTyID,        // Array... pointer...
64    OpaqueTyID,                         // Opaque type instances...
65    //PackedTyID  ,                     // SIMD 'packed' format... TODO
66    //...
67
68    NumPrimitiveIDs,                    // Must remain as last defined ID
69    FirstDerivedTyID = FunctionTyID,
70  };
71
72private:
73  PrimitiveID ID;        // The current base type of this type...
74  unsigned    UID;       // The unique ID number for this class
75  std::string Desc;      // The printed name of the string...
76  bool        Abstract;  // True if type contains an OpaqueType
77  bool        Recursive; // True if the type is recursive
78
79protected:
80  /// ctor is protected, so only subclasses can create Type objects...
81  Type(const std::string &Name, PrimitiveID id);
82  virtual ~Type() {}
83
84  /// When types are refined, they update their description to be more concrete.
85  ///
86  inline void setDescription(const std::string &D) { Desc = D; }
87
88  /// setName - Associate the name with this type in the symbol table, but don't
89  /// set the local name to be equal specified name.
90  ///
91  virtual void setName(const std::string &Name, SymbolTable *ST = 0);
92
93  /// Types can become nonabstract later, if they are refined.
94  ///
95  inline void setAbstract(bool Val) { Abstract = Val; }
96
97  /// Types can become recursive later, if they are refined.
98  ///
99  inline void setRecursive(bool Val) { Recursive = Val; }
100
101public:
102  virtual void print(std::ostream &O) const;
103
104  //===--------------------------------------------------------------------===//
105  // Property accessors for dealing with types... Some of these virtual methods
106  // are defined in private classes defined in Type.cpp for primitive types.
107  //
108
109  /// getPrimitiveID - Return the base type of the type.  This will return one
110  /// of the PrimitiveID enum elements defined above.
111  ///
112  inline PrimitiveID getPrimitiveID() const { return ID; }
113
114  /// getUniqueID - Returns the UID of the type.  This can be thought of as a
115  /// small integer version of the pointer to the type class.  Two types that
116  /// are structurally different have different UIDs.  This can be used for
117  /// indexing types into an array.
118  ///
119  inline unsigned getUniqueID() const { return UID; }
120
121  /// getDescription - Return the string representation of the type...
122  inline const std::string &getDescription() const { return Desc; }
123
124  /// isSigned - Return whether a numeric type is signed.
125  virtual bool isSigned() const { return 0; }
126
127  /// isUnsigned - Return whether a numeric type is unsigned.  This is not
128  /// quite the complement of isSigned... nonnumeric types return false as they
129  /// do with isSigned.
130  ///
131  virtual bool isUnsigned() const { return 0; }
132
133  /// isIntegral - Equilivent to isSigned() || isUnsigned, but with only a
134  /// single virtual function invocation.
135  ///
136  virtual bool isIntegral() const { return 0; }
137
138  /// isFloatingPoint - Return true if this is one of the two floating point
139  /// types
140  bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
141
142  /// isAbstract - True if the type is either an Opaque type, or is a derived
143  /// type that includes an opaque type somewhere in it.
144  ///
145  inline bool isAbstract() const { return Abstract; }
146
147  /// isRecursive - True if the type graph contains a cycle.
148  ///
149  inline bool isRecursive() const { return Recursive; }
150
151  /// isLosslesslyConvertableTo - Return true if this type can be converted to
152  /// 'Ty' without any reinterpretation of bits.  For example, uint to int.
153  ///
154  bool isLosslesslyConvertableTo(const Type *Ty) const;
155
156
157  /// Here are some useful little methods to query what type derived types are
158  /// Note that all other types can just compare to see if this == Type::xxxTy;
159  ///
160  inline bool isPrimitiveType() const { return ID < FirstDerivedTyID;  }
161  inline bool isDerivedType()   const { return ID >= FirstDerivedTyID; }
162
163  /// isFirstClassType - Return true if the value is holdable in a register.
164  inline bool isFirstClassType() const {
165    return isPrimitiveType() || ID == PointerTyID;
166  }
167
168  /// isSized - Return true if it makes sense to take the size of this type.  To
169  /// get the actual size for a particular target, it is reasonable to use the
170  /// TargetData subsystem to do this.
171  ///
172  bool isSized() const {
173    return ID != VoidTyID && ID != TypeTyID &&
174           ID != FunctionTyID && ID != LabelTyID && ID != OpaqueTyID;
175  }
176
177  /// getPrimitiveSize - Return the basic size of this type if it is a primative
178  /// type.  These are fixed by LLVM and are not target dependant.  This will
179  /// return zero if the type does not have a size or is not a primitive type.
180  ///
181  unsigned getPrimitiveSize() const;
182
183
184  //===--------------------------------------------------------------------===//
185  // Type Iteration support
186  //
187  class TypeIterator;
188  typedef TypeIterator subtype_iterator;
189  inline subtype_iterator subtype_begin() const;   // DEFINED BELOW
190  inline subtype_iterator subtype_end() const;     // DEFINED BELOW
191
192  /// getContainedType - This method is used to implement the type iterator
193  /// (defined a the end of the file).  For derived types, this returns the
194  /// types 'contained' in the derived type, returning 0 when 'i' becomes
195  /// invalid. This allows the user to iterate over the types in a struct, for
196  /// example, really easily.
197  ///
198  virtual const Type *getContainedType(unsigned i) const { return 0; }
199
200  /// getNumContainedTypes - Return the number of types in the derived type
201  virtual unsigned getNumContainedTypes() const { return 0; }
202
203  //===--------------------------------------------------------------------===//
204  // Static members exported by the Type class itself.  Useful for getting
205  // instances of Type.
206  //
207
208  /// getPrimitiveType/getUniqueIDType - Return a type based on an identifier.
209  static const Type *getPrimitiveType(PrimitiveID IDNumber);
210  static const Type *getUniqueIDType(unsigned UID);
211
212  //===--------------------------------------------------------------------===//
213  // These are the builtin types that are always available...
214  //
215  static Type *VoidTy , *BoolTy;
216  static Type *SByteTy, *UByteTy,
217              *ShortTy, *UShortTy,
218              *IntTy  , *UIntTy,
219              *LongTy , *ULongTy;
220  static Type *FloatTy, *DoubleTy;
221
222  static Type *TypeTy , *LabelTy;
223
224  /// Methods for support type inquiry through isa, cast, and dyn_cast:
225  static inline bool classof(const Type *T) { return true; }
226  static inline bool classof(const Value *V) {
227    return V->getValueType() == Value::TypeVal;
228  }
229
230#include "llvm/Type.def"
231
232private:
233  class TypeIterator : public bidirectional_iterator<const Type, ptrdiff_t> {
234    const Type * const Ty;
235    unsigned Idx;
236
237    typedef TypeIterator _Self;
238  public:
239    inline TypeIterator(const Type *ty, unsigned idx) : Ty(ty), Idx(idx) {}
240    inline ~TypeIterator() {}
241
242    inline bool operator==(const _Self& x) const { return Idx == x.Idx; }
243    inline bool operator!=(const _Self& x) const { return !operator==(x); }
244
245    inline pointer operator*() const { return Ty->getContainedType(Idx); }
246    inline pointer operator->() const { return operator*(); }
247
248    inline _Self& operator++() { ++Idx; return *this; } // Preincrement
249    inline _Self operator++(int) { // Postincrement
250      _Self tmp = *this; ++*this; return tmp;
251    }
252
253    inline _Self& operator--() { --Idx; return *this; }  // Predecrement
254    inline _Self operator--(int) { // Postdecrement
255      _Self tmp = *this; --*this; return tmp;
256    }
257  };
258};
259
260inline Type::TypeIterator Type::subtype_begin() const {
261  return TypeIterator(this, 0);
262}
263
264inline Type::TypeIterator Type::subtype_end() const {
265  return TypeIterator(this, getNumContainedTypes());
266}
267
268
269// Provide specializations of GraphTraits to be able to treat a type as a
270// graph of sub types...
271
272template <> struct GraphTraits<Type*> {
273  typedef Type NodeType;
274  typedef Type::subtype_iterator ChildIteratorType;
275
276  static inline NodeType *getEntryNode(Type *T) { return T; }
277  static inline ChildIteratorType child_begin(NodeType *N) {
278    return N->subtype_begin();
279  }
280  static inline ChildIteratorType child_end(NodeType *N) {
281    return N->subtype_end();
282  }
283};
284
285template <> struct GraphTraits<const Type*> {
286  typedef const Type NodeType;
287  typedef Type::subtype_iterator ChildIteratorType;
288
289  static inline NodeType *getEntryNode(const Type *T) { return T; }
290  static inline ChildIteratorType child_begin(NodeType *N) {
291    return N->subtype_begin();
292  }
293  static inline ChildIteratorType child_end(NodeType *N) {
294    return N->subtype_end();
295  }
296};
297
298template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
299  return Ty.getPrimitiveID() == Type::PointerTyID;
300}
301
302#endif
303