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, unless they are an abstract type
19 // that is resolved to a more concrete type.
21 // Opaque types are simple derived types with no state. There may be many
22 // different Opaque type objects floating around, but two are only considered
23 // identical if they are pointer equals of each other. This allows us to have
24 // two opaque types that end up resolving to different concrete types later.
26 // Opaque types are also kinda wierd and scary and different because they have
27 // to keep a list of uses of the type. When, through linking, parsing, or
28 // bytecode reading, they become resolved, they need to find and update all
29 // users of the unknown type, causing them to reference a new, more concrete
30 // type. Opaque types are deleted when their use list dwindles to zero users.
32 // Opaque types are considered to be first-class types.
34 //===----------------------------------------------------------------------===//
39 #include "AbstractTypeUser.h"
40 #include "llvm/Support/Casting.h"
41 #include "llvm/ADT/GraphTraits.h"
42 #include "llvm/ADT/iterator"
57 ///===-------------------------------------------------------------------===//
58 /// Definitions of all of the base types for the Type system. Based on this
59 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
60 /// Note: If you add an element to this, you need to add an element to the
61 /// Type::getPrimitiveType function, or else things will break!
64 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
65 VoidTyID = 0 , BoolTyID, // 0, 1: Basics...
66 UByteTyID , SByteTyID, // 2, 3: 8 bit types...
67 UShortTyID , ShortTyID, // 4, 5: 16 bit types...
68 UIntTyID , IntTyID, // 6, 7: 32 bit types...
69 ULongTyID , LongTyID, // 8, 9: 64 bit types...
70 FloatTyID , DoubleTyID, // 10,11: Floating point types...
71 LabelTyID , // 12 : Labels...
73 // Derived types... see DerivedTypes.h file...
74 // Make sure FirstDerivedTyID stays up to date!!!
75 FunctionTyID , StructTyID, // Functions... Structs...
76 ArrayTyID , PointerTyID, // Array... pointer...
77 OpaqueTyID, // Opaque type instances...
78 PackedTyID, // SIMD 'packed' format...
81 NumTypeIDs, // Must remain as last defined ID
82 LastPrimitiveTyID = LabelTyID,
83 FirstDerivedTyID = FunctionTyID,
87 TypeID ID : 8; // The current base type of this type.
88 bool Abstract; // True if type contains an OpaqueType
90 /// RefCount - This counts the number of PATypeHolders that are pointing to
91 /// this type. When this number falls to zero, if the type is abstract and
92 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
95 mutable unsigned RefCount;
97 const Type *getForwardedTypeInternal() const;
99 Type(const std::string& Name, TypeID id);
102 /// Types can become nonabstract later, if they are refined.
104 inline void setAbstract(bool Val) { Abstract = Val; }
106 // PromoteAbstractToConcrete - This is an internal method used to calculate
107 // change "Abstract" from true to false when types are refined.
108 void PromoteAbstractToConcrete();
110 unsigned getRefCount() const { return RefCount; }
112 /// ForwardType - This field is used to implement the union find scheme for
113 /// abstract types. When types are refined to other types, this field is set
114 /// to the more refined type. Only abstract types can be forwarded.
115 mutable const Type *ForwardType;
117 /// ContainedTys - The list of types contained by this one. For example, this
118 /// includes the arguments of a function type, the elements of the structure,
119 /// the pointee of a pointer, etc. Note that keeping this vector in the Type
120 /// class wastes some space for types that do not contain anything (such as
121 /// primitive types). However, keeping it here allows the subtype_* members
122 /// to be implemented MUCH more efficiently, and dynamically very few types do
123 /// not contain any elements (most are derived).
124 std::vector<PATypeHandle> ContainedTys;
127 virtual void print(std::ostream &O) const;
129 /// @brief Debugging support: print to stderr
130 virtual void dump() const;
132 //===--------------------------------------------------------------------===//
133 // Property accessors for dealing with types... Some of these virtual methods
134 // are defined in private classes defined in Type.cpp for primitive types.
137 /// getTypeID - Return the type id for the type. This will return one
138 /// of the TypeID enum elements defined above.
140 inline TypeID getTypeID() const { return ID; }
142 /// getDescription - Return the string representation of the type...
143 const std::string &getDescription() const;
145 /// isSigned - Return whether an integral numeric type is signed. This is
146 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for
147 /// Float and Double.
149 bool isSigned() const {
150 return ID == SByteTyID || ID == ShortTyID ||
151 ID == IntTyID || ID == LongTyID;
154 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite
155 /// the complement of isSigned... nonnumeric types return false as they do
156 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and
159 bool isUnsigned() const {
160 return ID == UByteTyID || ID == UShortTyID ||
161 ID == UIntTyID || ID == ULongTyID;
164 /// isInteger - Equivalent to isSigned() || isUnsigned()
166 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; }
168 /// isIntegral - Returns true if this is an integral type, which is either
169 /// BoolTy or one of the Integer types.
171 bool isIntegral() const { return isInteger() || this == BoolTy; }
173 /// isFloatingPoint - Return true if this is one of the two floating point
175 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
177 /// isAbstract - True if the type is either an Opaque type, or is a derived
178 /// type that includes an opaque type somewhere in it.
180 inline bool isAbstract() const { return Abstract; }
182 /// isLosslesslyConvertibleTo - Return true if this type can be converted to
183 /// 'Ty' without any reinterpretation of bits. For example, uint to int.
185 bool isLosslesslyConvertibleTo(const Type *Ty) const;
188 /// Here are some useful little methods to query what type derived types are
189 /// Note that all other types can just compare to see if this == Type::xxxTy;
191 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
192 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
194 /// isFirstClassType - Return true if the value is holdable in a register.
195 /// Note that we consider opaque types to be first class, as they may be
196 /// resolved to a first class type later.
197 inline bool isFirstClassType() const {
198 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
199 ID == PointerTyID || ID == PackedTyID || ID == OpaqueTyID;
202 /// isSized - Return true if it makes sense to take the size of this type. To
203 /// get the actual size for a particular target, it is reasonable to use the
204 /// TargetData subsystem to do this.
206 bool isSized() const {
207 return (ID >= BoolTyID && ID <= DoubleTyID) || ID == PointerTyID ||
208 isSizedDerivedType();
211 /// getPrimitiveSize - Return the basic size of this type if it is a primitive
212 /// type. These are fixed by LLVM and are not target dependent. This will
213 /// return zero if the type does not have a size or is not a primitive type.
215 unsigned getPrimitiveSize() const;
217 /// getUnsignedVersion - If this is an integer type, return the unsigned
218 /// variant of this type. For example int -> uint.
219 const Type *getUnsignedVersion() const;
221 /// getSignedVersion - If this is an integer type, return the signed variant
222 /// of this type. For example uint -> int.
223 const Type *getSignedVersion() const;
225 /// getForwaredType - Return the type that this type has been resolved to if
226 /// it has been resolved to anything. This is used to implement the
227 /// union-find algorithm for type resolution, and shouldn't be used by general
229 const Type *getForwardedType() const {
230 if (!ForwardType) return 0;
231 return getForwardedTypeInternal();
234 //===--------------------------------------------------------------------===//
235 // Type Iteration support
237 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator;
238 subtype_iterator subtype_begin() const { return ContainedTys.begin(); }
239 subtype_iterator subtype_end() const { return ContainedTys.end(); }
241 /// getContainedType - This method is used to implement the type iterator
242 /// (defined a the end of the file). For derived types, this returns the
243 /// types 'contained' in the derived type.
245 const Type *getContainedType(unsigned i) const {
246 assert(i < ContainedTys.size() && "Index out of range!");
247 return ContainedTys[i];
250 /// getNumContainedTypes - Return the number of types in the derived type.
252 unsigned getNumContainedTypes() const { return ContainedTys.size(); }
254 //===--------------------------------------------------------------------===//
255 // Static members exported by the Type class itself. Useful for getting
256 // instances of Type.
259 /// getPrimitiveType - Return a type based on an identifier.
260 static const Type *getPrimitiveType(TypeID IDNumber);
262 //===--------------------------------------------------------------------===//
263 // These are the builtin types that are always available...
265 static Type *VoidTy , *BoolTy;
266 static Type *SByteTy, *UByteTy,
270 static Type *FloatTy, *DoubleTy;
272 static Type* LabelTy;
274 /// Methods for support type inquiry through isa, cast, and dyn_cast:
275 static inline bool classof(const Type *T) { return true; }
277 #include "llvm/Type.def"
279 // Virtual methods used by callbacks below. These should only be implemented
280 // in the DerivedType class.
281 virtual void addAbstractTypeUser(AbstractTypeUser *U) const {
282 abort(); // Only on derived types!
284 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const {
285 abort(); // Only on derived types!
288 void addRef() const {
289 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
293 void dropRef() const {
294 assert(isAbstract() && "Cannot drop a refernce to a non-abstract type!");
295 assert(RefCount && "No objects are currently referencing this object!");
297 // If this is the last PATypeHolder using this object, and there are no
298 // PATypeHandles using it, the type is dead, delete it now.
303 /// isSizedDerivedType - Derived types like structures and arrays are sized
304 /// iff all of the members of the type are sized as well. Since asking for
305 /// their size is relatively uncommon, move this operation out of line.
306 bool isSizedDerivedType() const;
308 virtual void RefCountIsZero() const {
309 abort(); // only on derived types!
314 //===----------------------------------------------------------------------===//
315 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
316 // These are defined here because they MUST be inlined, yet are dependent on
317 // the definition of the Type class. Of course Type derives from Value, which
318 // contains an AbstractTypeUser instance, so there is no good way to factor out
319 // the code. Hence this bit of uglyness.
321 // In the long term, Type should not derive from Value, allowing
322 // AbstractTypeUser.h to #include Type.h, allowing us to eliminate this
323 // nastyness entirely.
325 inline void PATypeHandle::addUser() {
326 assert(Ty && "Type Handle has a null type!");
327 if (Ty->isAbstract())
328 Ty->addAbstractTypeUser(User);
330 inline void PATypeHandle::removeUser() {
331 if (Ty->isAbstract())
332 Ty->removeAbstractTypeUser(User);
335 inline void PATypeHandle::removeUserFromConcrete() {
336 if (!Ty->isAbstract())
337 Ty->removeAbstractTypeUser(User);
340 // Define inline methods for PATypeHolder...
342 inline void PATypeHolder::addRef() {
343 if (Ty->isAbstract())
347 inline void PATypeHolder::dropRef() {
348 if (Ty->isAbstract())
352 /// get - This implements the forwarding part of the union-find algorithm for
353 /// abstract types. Before every access to the Type*, we check to see if the
354 /// type we are pointing to is forwarding to a new type. If so, we drop our
355 /// reference to the type.
357 inline Type* PATypeHolder::get() const {
358 const Type *NewTy = Ty->getForwardedType();
359 if (!NewTy) return const_cast<Type*>(Ty);
360 return *const_cast<PATypeHolder*>(this) = NewTy;
365 //===----------------------------------------------------------------------===//
366 // Provide specializations of GraphTraits to be able to treat a type as a
367 // graph of sub types...
369 template <> struct GraphTraits<Type*> {
370 typedef Type NodeType;
371 typedef Type::subtype_iterator ChildIteratorType;
373 static inline NodeType *getEntryNode(Type *T) { return T; }
374 static inline ChildIteratorType child_begin(NodeType *N) {
375 return N->subtype_begin();
377 static inline ChildIteratorType child_end(NodeType *N) {
378 return N->subtype_end();
382 template <> struct GraphTraits<const Type*> {
383 typedef const Type NodeType;
384 typedef Type::subtype_iterator ChildIteratorType;
386 static inline NodeType *getEntryNode(const Type *T) { return T; }
387 static inline ChildIteratorType child_begin(NodeType *N) {
388 return N->subtype_begin();
390 static inline ChildIteratorType child_end(NodeType *N) {
391 return N->subtype_end();
395 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
396 return Ty.getTypeID() == Type::PointerTyID;
399 std::ostream &operator<<(std::ostream &OS, const Type &T);
401 } // End llvm namespace