1 //===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===//
3 // This file contains the declaration of the Type class. For more "Type" type
4 // stuff, look in DerivedTypes.h.
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.
11 // Types, once allocated, are never free'd.
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.
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.
24 //===----------------------------------------------------------------------===//
29 #include "llvm/Value.h"
30 #include "Support/GraphTraits.h"
31 #include "Support/iterator"
40 struct Type : public Value {
41 ///===-------------------------------------------------------------------===//
42 /// Definitions of all of the base types for the Type system. Based on this
43 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
44 /// Note: If you add an element to this, you need to add an element to the
45 /// Type::getPrimitiveType function, or else things will break!
48 VoidTyID = 0 , BoolTyID, // 0, 1: Basics...
49 UByteTyID , SByteTyID, // 2, 3: 8 bit types...
50 UShortTyID , ShortTyID, // 4, 5: 16 bit types...
51 UIntTyID , IntTyID, // 6, 7: 32 bit types...
52 ULongTyID , LongTyID, // 8, 9: 64 bit types...
54 FloatTyID , DoubleTyID, // 10,11: Floating point types...
56 TypeTyID, // 12 : Type definitions
57 LabelTyID , // 13 : Labels...
59 // Derived types... see DerivedTypes.h file...
60 // Make sure FirstDerivedTyID stays up to date!!!
61 FunctionTyID , StructTyID, // Functions... Structs...
62 ArrayTyID , PointerTyID, // Array... pointer...
63 OpaqueTyID, // Opaque type instances...
64 //PackedTyID , // SIMD 'packed' format... TODO
67 NumPrimitiveIDs, // Must remain as last defined ID
68 FirstDerivedTyID = FunctionTyID,
72 PrimitiveID ID; // The current base type of this type...
73 unsigned UID; // The unique ID number for this class
74 bool Abstract; // True if type contains an OpaqueType
76 const Type *getForwardedTypeInternal() const;
78 /// ctor is protected, so only subclasses can create Type objects...
79 Type(const std::string &Name, PrimitiveID id);
82 /// setName - Associate the name with this type in the symbol table, but don't
83 /// set the local name to be equal specified name.
85 virtual void setName(const std::string &Name, SymbolTable *ST = 0);
87 /// Types can become nonabstract later, if they are refined.
89 inline void setAbstract(bool Val) { Abstract = Val; }
91 /// isTypeAbstract - This method is used to calculate the Abstract bit.
93 bool isTypeAbstract();
95 /// ForwardType - This field is used to implement the union find scheme for
96 /// abstract types. When types are refined to other types, this field is set
97 /// to the more refined type. Only abstract types can be forwarded.
98 mutable const Type *ForwardType;
101 virtual void print(std::ostream &O) const;
103 //===--------------------------------------------------------------------===//
104 // Property accessors for dealing with types... Some of these virtual methods
105 // are defined in private classes defined in Type.cpp for primitive types.
108 /// getPrimitiveID - Return the base type of the type. This will return one
109 /// of the PrimitiveID enum elements defined above.
111 inline PrimitiveID getPrimitiveID() const { return ID; }
113 /// getUniqueID - Returns the UID of the type. This can be thought of as a
114 /// small integer version of the pointer to the type class. Two types that
115 /// are structurally different have different UIDs. This can be used for
116 /// indexing types into an array.
118 inline unsigned getUniqueID() const { return UID; }
120 /// getDescription - Return the string representation of the type...
121 const std::string &getDescription() const;
123 /// isSigned - Return whether an integral numeric type is signed. This is
124 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for
125 /// Float and Double.
127 virtual bool isSigned() const { return 0; }
129 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite
130 /// the complement of isSigned... nonnumeric types return false as they do
131 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and
134 virtual bool isUnsigned() const { return 0; }
136 /// isInteger - Equilivent to isSigned() || isUnsigned(), but with only a
137 /// single virtual function invocation.
139 virtual bool isInteger() const { return 0; }
141 /// isIntegral - Returns true if this is an integral type, which is either
142 /// BoolTy or one of the Integer types.
144 bool isIntegral() const { return isInteger() || this == BoolTy; }
146 /// isFloatingPoint - Return true if this is one of the two floating point
148 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
150 /// isAbstract - True if the type is either an Opaque type, or is a derived
151 /// type that includes an opaque type somewhere in it.
153 inline bool isAbstract() const { return Abstract; }
155 /// isLosslesslyConvertibleTo - Return true if this type can be converted to
156 /// 'Ty' without any reinterpretation of bits. For example, uint to int.
158 bool isLosslesslyConvertibleTo(const Type *Ty) const;
161 /// Here are some useful little methods to query what type derived types are
162 /// Note that all other types can just compare to see if this == Type::xxxTy;
164 inline bool isPrimitiveType() const { return ID < FirstDerivedTyID; }
165 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
167 /// isFirstClassType - Return true if the value is holdable in a register.
168 inline bool isFirstClassType() const {
169 return isPrimitiveType() || ID == PointerTyID;
172 /// isSized - Return true if it makes sense to take the size of this type. To
173 /// get the actual size for a particular target, it is reasonable to use the
174 /// TargetData subsystem to do this.
176 bool isSized() const {
177 return ID != VoidTyID && ID != TypeTyID &&
178 ID != FunctionTyID && ID != LabelTyID && ID != OpaqueTyID;
181 /// getPrimitiveSize - Return the basic size of this type if it is a primative
182 /// type. These are fixed by LLVM and are not target dependent. This will
183 /// return zero if the type does not have a size or is not a primitive type.
185 unsigned getPrimitiveSize() const;
187 /// getForwaredType - Return the type that this type has been resolved to if
188 /// it has been resolved to anything. This is used to implement the
189 /// union-find algorithm for type resolution.
190 const Type *getForwardedType() const {
191 if (!ForwardType) return 0;
192 return getForwardedTypeInternal();
195 //===--------------------------------------------------------------------===//
196 // Type Iteration support
199 typedef TypeIterator subtype_iterator;
200 inline subtype_iterator subtype_begin() const; // DEFINED BELOW
201 inline subtype_iterator subtype_end() const; // DEFINED BELOW
203 /// getContainedType - This method is used to implement the type iterator
204 /// (defined a the end of the file). For derived types, this returns the
205 /// types 'contained' in the derived type.
207 virtual const Type *getContainedType(unsigned i) const {
208 assert(0 && "No contained types!");
212 /// getNumContainedTypes - Return the number of types in the derived type
213 virtual unsigned getNumContainedTypes() const { return 0; }
215 //===--------------------------------------------------------------------===//
216 // Static members exported by the Type class itself. Useful for getting
217 // instances of Type.
220 /// getPrimitiveType/getUniqueIDType - Return a type based on an identifier.
221 static const Type *getPrimitiveType(PrimitiveID IDNumber);
222 static const Type *getUniqueIDType(unsigned UID);
224 //===--------------------------------------------------------------------===//
225 // These are the builtin types that are always available...
227 static Type *VoidTy , *BoolTy;
228 static Type *SByteTy, *UByteTy,
232 static Type *FloatTy, *DoubleTy;
234 static Type *TypeTy , *LabelTy;
236 /// Methods for support type inquiry through isa, cast, and dyn_cast:
237 static inline bool classof(const Type *T) { return true; }
238 static inline bool classof(const Value *V) {
239 return V->getValueType() == Value::TypeVal;
242 #include "llvm/Type.def"
245 class TypeIterator : public bidirectional_iterator<const Type, ptrdiff_t> {
246 const Type * const Ty;
249 typedef TypeIterator _Self;
251 TypeIterator(const Type *ty, unsigned idx) : Ty(ty), Idx(idx) {}
254 bool operator==(const _Self& x) const { return Idx == x.Idx; }
255 bool operator!=(const _Self& x) const { return !operator==(x); }
257 pointer operator*() const { return Ty->getContainedType(Idx); }
258 pointer operator->() const { return operator*(); }
260 _Self& operator++() { ++Idx; return *this; } // Preincrement
261 _Self operator++(int) { // Postincrement
262 _Self tmp = *this; ++*this; return tmp;
265 _Self& operator--() { --Idx; return *this; } // Predecrement
266 _Self operator--(int) { // Postdecrement
267 _Self tmp = *this; --*this; return tmp;
272 inline Type::TypeIterator Type::subtype_begin() const {
273 return TypeIterator(this, 0);
276 inline Type::TypeIterator Type::subtype_end() const {
277 return TypeIterator(this, getNumContainedTypes());
281 // Provide specializations of GraphTraits to be able to treat a type as a
282 // graph of sub types...
284 template <> struct GraphTraits<Type*> {
285 typedef Type NodeType;
286 typedef Type::subtype_iterator ChildIteratorType;
288 static inline NodeType *getEntryNode(Type *T) { return T; }
289 static inline ChildIteratorType child_begin(NodeType *N) {
290 return N->subtype_begin();
292 static inline ChildIteratorType child_end(NodeType *N) {
293 return N->subtype_end();
297 template <> struct GraphTraits<const Type*> {
298 typedef const Type NodeType;
299 typedef Type::subtype_iterator ChildIteratorType;
301 static inline NodeType *getEntryNode(const Type *T) { return T; }
302 static inline ChildIteratorType child_begin(NodeType *N) {
303 return N->subtype_begin();
305 static inline ChildIteratorType child_end(NodeType *N) {
306 return N->subtype_end();
310 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
311 return Ty.getPrimitiveID() == Type::PointerTyID;