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 //===----------------------------------------------------------------------===//
37 #include "AbstractTypeUser.h"
38 #include "llvm/Support/Casting.h"
39 #include "llvm/ADT/GraphTraits.h"
40 #include "llvm/ADT/iterator"
55 ///===-------------------------------------------------------------------===//
56 /// Definitions of all of the base types for the Type system. Based on this
57 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
58 /// Note: If you add an element to this, you need to add an element to the
59 /// Type::getPrimitiveType function, or else things will break!
62 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
63 VoidTyID = 0 , BoolTyID, // 0, 1: Basics...
64 UByteTyID , SByteTyID, // 2, 3: 8 bit types...
65 UShortTyID , ShortTyID, // 4, 5: 16 bit types...
66 UIntTyID , IntTyID, // 6, 7: 32 bit types...
67 ULongTyID , LongTyID, // 8, 9: 64 bit types...
68 FloatTyID , DoubleTyID, // 10,11: Floating point types...
69 LabelTyID , // 12 : Labels...
71 // Derived types... see DerivedTypes.h file...
72 // Make sure FirstDerivedTyID stays up to date!!!
73 FunctionTyID , StructTyID, // Functions... Structs...
74 ArrayTyID , PointerTyID, // Array... pointer...
75 OpaqueTyID, // Opaque type instances...
76 PackedTyID, // SIMD 'packed' format...
79 NumTypeIDs, // Must remain as last defined ID
80 LastPrimitiveTyID = LabelTyID,
81 FirstDerivedTyID = FunctionTyID,
85 TypeID ID : 8; // The current base type of this type.
86 bool Abstract; // True if type contains an OpaqueType
88 /// RefCount - This counts the number of PATypeHolders that are pointing to
89 /// this type. When this number falls to zero, if the type is abstract and
90 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
93 mutable unsigned RefCount;
95 const Type *getForwardedTypeInternal() const;
97 Type(const std::string& Name, TypeID id);
100 /// Types can become nonabstract later, if they are refined.
102 inline void setAbstract(bool Val) { Abstract = Val; }
104 // PromoteAbstractToConcrete - This is an internal method used to calculate
105 // change "Abstract" from true to false when types are refined.
106 void PromoteAbstractToConcrete();
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 //===--------------------------------------------------------------------===//
131 // Property accessors for dealing with types... Some of these virtual methods
132 // are defined in private classes defined in Type.cpp for primitive types.
135 /// getTypeID - Return the type id for the type. This will return one
136 /// of the TypeID enum elements defined above.
138 inline TypeID getTypeID() const { return ID; }
140 /// getDescription - Return the string representation of the type...
141 const std::string &getDescription() const;
143 /// isSigned - Return whether an integral numeric type is signed. This is
144 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for
145 /// Float and Double.
147 bool isSigned() const {
148 return ID == SByteTyID || ID == ShortTyID ||
149 ID == IntTyID || ID == LongTyID;
152 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite
153 /// the complement of isSigned... nonnumeric types return false as they do
154 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and
157 bool isUnsigned() const {
158 return ID == UByteTyID || ID == UShortTyID ||
159 ID == UIntTyID || ID == ULongTyID;
162 /// isInteger - Equivalent to isSigned() || isUnsigned()
164 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; }
166 /// isIntegral - Returns true if this is an integral type, which is either
167 /// BoolTy or one of the Integer types.
169 bool isIntegral() const { return isInteger() || this == BoolTy; }
171 /// isFloatingPoint - Return true if this is one of the two floating point
173 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
175 /// isAbstract - True if the type is either an Opaque type, or is a derived
176 /// type that includes an opaque type somewhere in it.
178 inline bool isAbstract() const { return Abstract; }
180 /// isLosslesslyConvertibleTo - Return true if this type can be converted to
181 /// 'Ty' without any reinterpretation of bits. For example, uint to int.
183 bool isLosslesslyConvertibleTo(const Type *Ty) const;
186 /// Here are some useful little methods to query what type derived types are
187 /// Note that all other types can just compare to see if this == Type::xxxTy;
189 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
190 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
192 /// isFirstClassType - Return true if the value is holdable in a register.
194 inline bool isFirstClassType() const {
195 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
196 ID == PointerTyID || ID == PackedTyID;
199 /// isSized - Return true if it makes sense to take the size of this type. To
200 /// get the actual size for a particular target, it is reasonable to use the
201 /// TargetData subsystem to do this.
203 bool isSized() const {
204 return !isAbstract() || ID == PointerTyID || isSizedDerivedType();
207 /// getPrimitiveSize - Return the basic size of this type if it is a primitive
208 /// type. These are fixed by LLVM and are not target dependent. This will
209 /// return zero if the type does not have a size or is not a primitive type.
211 unsigned getPrimitiveSize() const;
213 /// getUnsignedVersion - If this is an integer type, return the unsigned
214 /// variant of this type. For example int -> uint.
215 const Type *getUnsignedVersion() const;
217 /// getSignedVersion - If this is an integer type, return the signed variant
218 /// of this type. For example uint -> int.
219 const Type *getSignedVersion() const;
221 /// getForwaredType - Return the type that this type has been resolved to if
222 /// it has been resolved to anything. This is used to implement the
223 /// union-find algorithm for type resolution, and shouldn't be used by general
225 const Type *getForwardedType() const {
226 if (!ForwardType) return 0;
227 return getForwardedTypeInternal();
230 //===--------------------------------------------------------------------===//
231 // Type Iteration support
233 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator;
234 subtype_iterator subtype_begin() const { return ContainedTys.begin(); }
235 subtype_iterator subtype_end() const { return ContainedTys.end(); }
237 /// getContainedType - This method is used to implement the type iterator
238 /// (defined a the end of the file). For derived types, this returns the
239 /// types 'contained' in the derived type.
241 const Type *getContainedType(unsigned i) const {
242 assert(i < ContainedTys.size() && "Index out of range!");
243 return ContainedTys[i];
246 /// getNumContainedTypes - Return the number of types in the derived type.
248 typedef std::vector<PATypeHandle>::size_type size_type;
249 size_type getNumContainedTypes() const { return ContainedTys.size(); }
251 //===--------------------------------------------------------------------===//
252 // Static members exported by the Type class itself. Useful for getting
253 // instances of Type.
256 /// getPrimitiveType - Return a type based on an identifier.
257 static const Type *getPrimitiveType(TypeID IDNumber);
259 //===--------------------------------------------------------------------===//
260 // These are the builtin types that are always available...
262 static Type *VoidTy , *BoolTy;
263 static Type *SByteTy, *UByteTy,
267 static Type *FloatTy, *DoubleTy;
269 static Type* LabelTy;
271 /// Methods for support type inquiry through isa, cast, and dyn_cast:
272 static inline bool classof(const Type *T) { return true; }
274 #include "llvm/Type.def"
276 // Virtual methods used by callbacks below. These should only be implemented
277 // in the DerivedType class.
278 virtual void addAbstractTypeUser(AbstractTypeUser *U) const {
279 abort(); // Only on derived types!
281 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const {
282 abort(); // Only on derived types!
285 void addRef() const {
286 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
290 void dropRef() const {
291 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
292 assert(RefCount && "No objects are currently referencing this object!");
294 // If this is the last PATypeHolder using this object, and there are no
295 // PATypeHandles using it, the type is dead, delete it now.
300 /// clearAllTypeMaps - This method frees all internal memory used by the
301 /// type subsystem, which can be used in environments where this memory is
302 /// otherwise reported as a leak.
303 static void clearAllTypeMaps();
306 /// isSizedDerivedType - Derived types like structures and arrays are sized
307 /// iff all of the members of the type are sized as well. Since asking for
308 /// their size is relatively uncommon, move this operation out of line.
309 bool isSizedDerivedType() const;
311 virtual void RefCountIsZero() const {
312 abort(); // only on derived types!
317 //===----------------------------------------------------------------------===//
318 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
319 // These are defined here because they MUST be inlined, yet are dependent on
320 // the definition of the Type class. Of course Type derives from Value, which
321 // contains an AbstractTypeUser instance, so there is no good way to factor out
322 // the code. Hence this bit of uglyness.
324 // In the long term, Type should not derive from Value, allowing
325 // AbstractTypeUser.h to #include Type.h, allowing us to eliminate this
326 // nastyness entirely.
328 inline void PATypeHandle::addUser() {
329 assert(Ty && "Type Handle has a null type!");
330 if (Ty->isAbstract())
331 Ty->addAbstractTypeUser(User);
333 inline void PATypeHandle::removeUser() {
334 if (Ty->isAbstract())
335 Ty->removeAbstractTypeUser(User);
338 inline void PATypeHandle::removeUserFromConcrete() {
339 if (!Ty->isAbstract())
340 Ty->removeAbstractTypeUser(User);
343 // Define inline methods for PATypeHolder...
345 inline void PATypeHolder::addRef() {
346 if (Ty->isAbstract())
350 inline void PATypeHolder::dropRef() {
351 if (Ty->isAbstract())
355 /// get - This implements the forwarding part of the union-find algorithm for
356 /// abstract types. Before every access to the Type*, we check to see if the
357 /// type we are pointing to is forwarding to a new type. If so, we drop our
358 /// reference to the type.
360 inline Type* PATypeHolder::get() const {
361 const Type *NewTy = Ty->getForwardedType();
362 if (!NewTy) return const_cast<Type*>(Ty);
363 return *const_cast<PATypeHolder*>(this) = NewTy;
368 //===----------------------------------------------------------------------===//
369 // Provide specializations of GraphTraits to be able to treat a type as a
370 // graph of sub types...
372 template <> struct GraphTraits<Type*> {
373 typedef Type NodeType;
374 typedef Type::subtype_iterator ChildIteratorType;
376 static inline NodeType *getEntryNode(Type *T) { return T; }
377 static inline ChildIteratorType child_begin(NodeType *N) {
378 return N->subtype_begin();
380 static inline ChildIteratorType child_end(NodeType *N) {
381 return N->subtype_end();
385 template <> struct GraphTraits<const Type*> {
386 typedef const Type NodeType;
387 typedef Type::subtype_iterator ChildIteratorType;
389 static inline NodeType *getEntryNode(const Type *T) { return T; }
390 static inline ChildIteratorType child_begin(NodeType *N) {
391 return N->subtype_begin();
393 static inline ChildIteratorType child_end(NodeType *N) {
394 return N->subtype_end();
398 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
399 return Ty.getTypeID() == Type::PointerTyID;
402 std::ostream &operator<<(std::ostream &OS, const Type &T);
404 } // End llvm namespace