1 //===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the declaration of the Type class. For more "Type" type
11 // stuff, look in DerivedTypes.h.
13 // Note that instances of the Type class are immutable: once they are created,
14 // they are never changed. Also note that only one instance of a particular
15 // type is ever created. Thus seeing if two types are equal is a matter of
16 // doing a trivial pointer comparison.
18 // Types, once allocated, are never free'd.
20 // Opaque types are simple derived types with no state. There may be many
21 // different Opaque type objects floating around, but two are only considered
22 // identical if they are pointer equals of each other. This allows us to have
23 // two opaque types that end up resolving to different concrete types later.
25 // Opaque types are also kinda wierd and scary and different because they have
26 // to keep a list of uses of the type. When, through linking, parsing, or
27 // bytecode reading, they become resolved, they need to find and update all
28 // users of the unknown type, causing them to reference a new, more concrete
29 // type. Opaque types are deleted when their use list dwindles to zero users.
31 //===----------------------------------------------------------------------===//
36 #include "llvm/Value.h"
37 #include "Support/GraphTraits.h"
38 #include "Support/iterator"
50 struct Type : public Value {
51 ///===-------------------------------------------------------------------===//
52 /// Definitions of all of the base types for the Type system. Based on this
53 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
54 /// Note: If you add an element to this, you need to add an element to the
55 /// Type::getPrimitiveType function, or else things will break!
58 VoidTyID = 0 , BoolTyID, // 0, 1: Basics...
59 UByteTyID , SByteTyID, // 2, 3: 8 bit types...
60 UShortTyID , ShortTyID, // 4, 5: 16 bit types...
61 UIntTyID , IntTyID, // 6, 7: 32 bit types...
62 ULongTyID , LongTyID, // 8, 9: 64 bit types...
64 FloatTyID , DoubleTyID, // 10,11: Floating point types...
66 TypeTyID, // 12 : Type definitions
67 LabelTyID , // 13 : Labels...
69 // Derived types... see DerivedTypes.h file...
70 // Make sure FirstDerivedTyID stays up to date!!!
71 FunctionTyID , StructTyID, // Functions... Structs...
72 ArrayTyID , PointerTyID, // Array... pointer...
73 OpaqueTyID, // Opaque type instances...
74 //PackedTyID , // SIMD 'packed' format... TODO
77 NumPrimitiveIDs, // Must remain as last defined ID
78 FirstDerivedTyID = FunctionTyID,
82 PrimitiveID ID; // The current base type of this type...
83 unsigned UID; // The unique ID number for this class
84 bool Abstract; // True if type contains an OpaqueType
86 /// RefCount - This counts the number of PATypeHolders that are pointing to
87 /// this type. When this number falls to zero, if the type is abstract and
88 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
91 mutable unsigned RefCount;
93 const Type *getForwardedTypeInternal() const;
95 /// ctor is protected, so only subclasses can create Type objects...
96 Type(const std::string &Name, PrimitiveID id);
100 /// Types can become nonabstract later, if they are refined.
102 inline void setAbstract(bool Val) { Abstract = Val; }
104 /// isTypeAbstract - This method is used to calculate the Abstract bit.
106 bool isTypeAbstract();
108 unsigned getRefCount() const { return RefCount; }
110 /// ForwardType - This field is used to implement the union find scheme for
111 /// abstract types. When types are refined to other types, this field is set
112 /// to the more refined type. Only abstract types can be forwarded.
113 mutable const Type *ForwardType;
115 /// ContainedTys - The list of types contained by this one. For example, this
116 /// includes the arguments of a function type, the elements of the structure,
117 /// the pointee of a pointer, etc. Note that keeping this vector in the Type
118 /// class wastes some space for types that do not contain anything (such as
119 /// primitive types). However, keeping it here allows the subtype_* members
120 /// to be implemented MUCH more efficiently, and dynamically very few types do
121 /// not contain any elements (most are derived).
122 std::vector<PATypeHandle> ContainedTys;
125 virtual void print(std::ostream &O) const;
127 /// @brief Debugging support: print to stderr
128 virtual void dump() const;
130 /// setName - Associate the name with this type in the symbol table, but don't
131 /// set the local name to be equal specified name.
133 virtual void setName(const std::string &Name, SymbolTable *ST = 0);
135 //===--------------------------------------------------------------------===//
136 // Property accessors for dealing with types... Some of these virtual methods
137 // are defined in private classes defined in Type.cpp for primitive types.
140 /// getPrimitiveID - Return the base type of the type. This will return one
141 /// of the PrimitiveID enum elements defined above.
143 inline PrimitiveID getPrimitiveID() const { return ID; }
145 /// getUniqueID - Returns the UID of the type. This can be thought of as a
146 /// small integer version of the pointer to the type class. Two types that
147 /// are structurally different have different UIDs. This can be used for
148 /// indexing types into an array.
150 inline unsigned getUniqueID() const { return UID; }
152 /// getDescription - Return the string representation of the type...
153 const std::string &getDescription() const;
155 /// isSigned - Return whether an integral numeric type is signed. This is
156 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for
157 /// Float and Double.
159 virtual bool isSigned() const { return 0; }
161 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite
162 /// the complement of isSigned... nonnumeric types return false as they do
163 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and
166 virtual bool isUnsigned() const { return 0; }
168 /// isInteger - Equilivent to isSigned() || isUnsigned(), but with only a
169 /// single virtual function invocation.
171 virtual bool isInteger() const { return 0; }
173 /// isIntegral - Returns true if this is an integral type, which is either
174 /// BoolTy or one of the Integer types.
176 bool isIntegral() const { return isInteger() || this == BoolTy; }
178 /// isFloatingPoint - Return true if this is one of the two floating point
180 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
182 /// isAbstract - True if the type is either an Opaque type, or is a derived
183 /// type that includes an opaque type somewhere in it.
185 inline bool isAbstract() const { return Abstract; }
187 /// isLosslesslyConvertibleTo - Return true if this type can be converted to
188 /// 'Ty' without any reinterpretation of bits. For example, uint to int.
190 bool isLosslesslyConvertibleTo(const Type *Ty) const;
193 /// Here are some useful little methods to query what type derived types are
194 /// Note that all other types can just compare to see if this == Type::xxxTy;
196 inline bool isPrimitiveType() const { return ID < FirstDerivedTyID; }
197 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
199 /// isFirstClassType - Return true if the value is holdable in a register.
200 inline bool isFirstClassType() const {
201 return (ID != VoidTyID && ID < TypeTyID) || ID == PointerTyID;
204 /// isSized - Return true if it makes sense to take the size of this type. To
205 /// get the actual size for a particular target, it is reasonable to use the
206 /// TargetData subsystem to do this.
208 bool isSized() const {
209 return ID != VoidTyID && ID != TypeTyID &&
210 ID != FunctionTyID && ID != LabelTyID && ID != OpaqueTyID;
213 /// getPrimitiveSize - Return the basic size of this type if it is a primative
214 /// type. These are fixed by LLVM and are not target dependent. This will
215 /// return zero if the type does not have a size or is not a primitive type.
217 unsigned getPrimitiveSize() const;
219 /// getUnsignedVersion - If this is an integer type, return the unsigned
220 /// variant of this type. For example int -> uint.
221 const Type *getUnsignedVersion() const;
223 /// getSignedVersion - If this is an integer type, return the signed variant
224 /// of this type. For example uint -> int.
225 const Type *getSignedVersion() const;
227 /// getForwaredType - Return the type that this type has been resolved to if
228 /// it has been resolved to anything. This is used to implement the
229 /// union-find algorithm for type resolution, and shouldn't be used by general
231 const Type *getForwardedType() const {
232 if (!ForwardType) return 0;
233 return getForwardedTypeInternal();
236 //===--------------------------------------------------------------------===//
237 // Type Iteration support
239 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator;
240 subtype_iterator subtype_begin() const { return ContainedTys.begin(); }
241 subtype_iterator subtype_end() const { return ContainedTys.end(); }
243 /// getContainedType - This method is used to implement the type iterator
244 /// (defined a the end of the file). For derived types, this returns the
245 /// types 'contained' in the derived type.
247 const Type *getContainedType(unsigned i) const {
248 assert(i < ContainedTys.size() && "Index out of range!");
249 return ContainedTys[i];
252 /// getNumContainedTypes - Return the number of types in the derived type.
254 unsigned getNumContainedTypes() const { return ContainedTys.size(); }
256 //===--------------------------------------------------------------------===//
257 // Static members exported by the Type class itself. Useful for getting
258 // instances of Type.
261 /// getPrimitiveType/getUniqueIDType - Return a type based on an identifier.
262 static const Type *getPrimitiveType(PrimitiveID IDNumber);
263 static const Type *getUniqueIDType(unsigned UID);
265 //===--------------------------------------------------------------------===//
266 // These are the builtin types that are always available...
268 static Type *VoidTy , *BoolTy;
269 static Type *SByteTy, *UByteTy,
273 static Type *FloatTy, *DoubleTy;
275 static Type *TypeTy , *LabelTy;
277 /// Methods for support type inquiry through isa, cast, and dyn_cast:
278 static inline bool classof(const Type *T) { return true; }
279 static inline bool classof(const Value *V) {
280 return V->getValueType() == Value::TypeVal;
283 #include "llvm/Type.def"
285 // Virtual methods used by callbacks below. These should only be implemented
286 // in the DerivedType class.
287 virtual void addAbstractTypeUser(AbstractTypeUser *U) const {
288 abort(); // Only on derived types!
290 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const {
291 abort(); // Only on derived types!
294 void addRef() const {
295 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
299 void dropRef() const {
300 assert(isAbstract() && "Cannot drop a refernce to a non-abstract type!");
301 assert(RefCount && "No objects are currently referencing this object!");
303 // If this is the last PATypeHolder using this object, and there are no
304 // PATypeHandles using it, the type is dead, delete it now.
309 virtual void RefCountIsZero() const {
310 abort(); // only on derived types!
315 //===----------------------------------------------------------------------===//
316 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
317 // These are defined here because they MUST be inlined, yet are dependent on
318 // the definition of the Type class. Of course Type derives from Value, which
319 // contains an AbstractTypeUser instance, so there is no good way to factor out
320 // the code. Hence this bit of uglyness.
322 // In the long term, Type should not derive from Value, allowing
323 // AbstractTypeUser.h to #include Type.h, allowing us to eliminate this
324 // nastyness entirely.
326 inline void PATypeHandle::addUser() {
327 assert(Ty && "Type Handle has a null type!");
328 if (Ty->isAbstract())
329 Ty->addAbstractTypeUser(User);
331 inline void PATypeHandle::removeUser() {
332 if (Ty->isAbstract())
333 Ty->removeAbstractTypeUser(User);
336 inline void PATypeHandle::removeUserFromConcrete() {
337 if (!Ty->isAbstract())
338 Ty->removeAbstractTypeUser(User);
341 // Define inline methods for PATypeHolder...
343 inline void PATypeHolder::addRef() {
344 if (Ty->isAbstract())
348 inline void PATypeHolder::dropRef() {
349 if (Ty->isAbstract())
353 /// get - This implements the forwarding part of the union-find algorithm for
354 /// abstract types. Before every access to the Type*, we check to see if the
355 /// type we are pointing to is forwarding to a new type. If so, we drop our
356 /// reference to the type.
358 inline const Type* PATypeHolder::get() const {
359 const Type *NewTy = Ty->getForwardedType();
360 if (!NewTy) return Ty;
361 return *const_cast<PATypeHolder*>(this) = NewTy;
366 //===----------------------------------------------------------------------===//
367 // Provide specializations of GraphTraits to be able to treat a type as a
368 // graph of sub types...
370 template <> struct GraphTraits<Type*> {
371 typedef Type NodeType;
372 typedef Type::subtype_iterator ChildIteratorType;
374 static inline NodeType *getEntryNode(Type *T) { return T; }
375 static inline ChildIteratorType child_begin(NodeType *N) {
376 return N->subtype_begin();
378 static inline ChildIteratorType child_end(NodeType *N) {
379 return N->subtype_end();
383 template <> struct GraphTraits<const Type*> {
384 typedef const Type NodeType;
385 typedef Type::subtype_iterator ChildIteratorType;
387 static inline NodeType *getEntryNode(const Type *T) { return T; }
388 static inline ChildIteratorType child_begin(NodeType *N) {
389 return N->subtype_begin();
391 static inline ChildIteratorType child_end(NodeType *N) {
392 return N->subtype_end();
396 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
397 return Ty.getPrimitiveID() == Type::PointerTyID;
400 } // End llvm namespace