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);
99 /// setName - Associate the name with this type in the symbol table, but don't
100 /// set the local name to be equal specified name.
102 virtual void setName(const std::string &Name, SymbolTable *ST = 0);
104 /// Types can become nonabstract later, if they are refined.
106 inline void setAbstract(bool Val) { Abstract = Val; }
108 /// isTypeAbstract - This method is used to calculate the Abstract bit.
110 bool isTypeAbstract();
112 unsigned getRefCount() const { return RefCount; }
114 /// ForwardType - This field is used to implement the union find scheme for
115 /// abstract types. When types are refined to other types, this field is set
116 /// to the more refined type. Only abstract types can be forwarded.
117 mutable const Type *ForwardType;
119 /// ContainedTys - The list of types contained by this one. For example, this
120 /// includes the arguments of a function type, the elements of the structure,
121 /// the pointee of a pointer, etc. Note that keeping this vector in the Type
122 /// class wastes some space for types that do not contain anything (such as
123 /// primitive types). However, keeping it here allows the subtype_* members
124 /// to be implemented MUCH more efficiently, and dynamically very few types do
125 /// not contain any elements (most are derived).
126 std::vector<PATypeHandle> ContainedTys;
129 virtual void print(std::ostream &O) const;
131 //===--------------------------------------------------------------------===//
132 // Property accessors for dealing with types... Some of these virtual methods
133 // are defined in private classes defined in Type.cpp for primitive types.
136 /// getPrimitiveID - Return the base type of the type. This will return one
137 /// of the PrimitiveID enum elements defined above.
139 inline PrimitiveID getPrimitiveID() const { return ID; }
141 /// getUniqueID - Returns the UID of the type. This can be thought of as a
142 /// small integer version of the pointer to the type class. Two types that
143 /// are structurally different have different UIDs. This can be used for
144 /// indexing types into an array.
146 inline unsigned getUniqueID() const { return UID; }
148 /// getDescription - Return the string representation of the type...
149 const std::string &getDescription() const;
151 /// isSigned - Return whether an integral numeric type is signed. This is
152 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for
153 /// Float and Double.
155 virtual bool isSigned() const { return 0; }
157 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite
158 /// the complement of isSigned... nonnumeric types return false as they do
159 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and
162 virtual bool isUnsigned() const { return 0; }
164 /// isInteger - Equilivent to isSigned() || isUnsigned(), but with only a
165 /// single virtual function invocation.
167 virtual bool isInteger() const { return 0; }
169 /// isIntegral - Returns true if this is an integral type, which is either
170 /// BoolTy or one of the Integer types.
172 bool isIntegral() const { return isInteger() || this == BoolTy; }
174 /// isFloatingPoint - Return true if this is one of the two floating point
176 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
178 /// isAbstract - True if the type is either an Opaque type, or is a derived
179 /// type that includes an opaque type somewhere in it.
181 inline bool isAbstract() const { return Abstract; }
183 /// isLosslesslyConvertibleTo - Return true if this type can be converted to
184 /// 'Ty' without any reinterpretation of bits. For example, uint to int.
186 bool isLosslesslyConvertibleTo(const Type *Ty) const;
189 /// Here are some useful little methods to query what type derived types are
190 /// Note that all other types can just compare to see if this == Type::xxxTy;
192 inline bool isPrimitiveType() const { return ID < FirstDerivedTyID; }
193 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
195 /// isFirstClassType - Return true if the value is holdable in a register.
196 inline bool isFirstClassType() const {
197 return (ID != VoidTyID && ID < TypeTyID) || ID == PointerTyID;
200 /// isSized - Return true if it makes sense to take the size of this type. To
201 /// get the actual size for a particular target, it is reasonable to use the
202 /// TargetData subsystem to do this.
204 bool isSized() const {
205 return ID != VoidTyID && ID != TypeTyID &&
206 ID != FunctionTyID && ID != LabelTyID && ID != OpaqueTyID;
209 /// getPrimitiveSize - Return the basic size of this type if it is a primative
210 /// type. These are fixed by LLVM and are not target dependent. This will
211 /// return zero if the type does not have a size or is not a primitive type.
213 unsigned getPrimitiveSize() const;
215 /// getUnsignedVersion - If this is an integer type, return the unsigned
216 /// variant of this type. For example int -> uint.
217 const Type *getUnsignedVersion() const;
219 /// getSignedVersion - If this is an integer type, return the signed variant
220 /// of this type. For example uint -> int.
221 const Type *getSignedVersion() const;
223 /// getForwaredType - Return the type that this type has been resolved to if
224 /// it has been resolved to anything. This is used to implement the
225 /// union-find algorithm for type resolution, and shouldn't be used by general
227 const Type *getForwardedType() const {
228 if (!ForwardType) return 0;
229 return getForwardedTypeInternal();
232 //===--------------------------------------------------------------------===//
233 // Type Iteration support
235 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator;
236 subtype_iterator subtype_begin() const { return ContainedTys.begin(); }
237 subtype_iterator subtype_end() const { return ContainedTys.end(); }
239 /// getContainedType - This method is used to implement the type iterator
240 /// (defined a the end of the file). For derived types, this returns the
241 /// types 'contained' in the derived type.
243 const Type *getContainedType(unsigned i) const {
244 assert(i < ContainedTys.size() && "Index out of range!");
245 return ContainedTys[i];
248 /// getNumContainedTypes - Return the number of types in the derived type.
250 unsigned getNumContainedTypes() const { return ContainedTys.size(); }
252 //===--------------------------------------------------------------------===//
253 // Static members exported by the Type class itself. Useful for getting
254 // instances of Type.
257 /// getPrimitiveType/getUniqueIDType - Return a type based on an identifier.
258 static const Type *getPrimitiveType(PrimitiveID IDNumber);
259 static const Type *getUniqueIDType(unsigned UID);
261 //===--------------------------------------------------------------------===//
262 // These are the builtin types that are always available...
264 static Type *VoidTy , *BoolTy;
265 static Type *SByteTy, *UByteTy,
269 static Type *FloatTy, *DoubleTy;
271 static Type *TypeTy , *LabelTy;
273 /// Methods for support type inquiry through isa, cast, and dyn_cast:
274 static inline bool classof(const Type *T) { return true; }
275 static inline bool classof(const Value *V) {
276 return V->getValueType() == Value::TypeVal;
279 #include "llvm/Type.def"
281 // Virtual methods used by callbacks below. These should only be implemented
282 // in the DerivedType class.
283 virtual void addAbstractTypeUser(AbstractTypeUser *U) const {
284 abort(); // Only on derived types!
286 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const {
287 abort(); // Only on derived types!
290 void addRef() const {
291 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
295 void dropRef() const {
296 assert(isAbstract() && "Cannot drop a refernce to a non-abstract type!");
297 assert(RefCount && "No objects are currently referencing this object!");
299 // If this is the last PATypeHolder using this object, and there are no
300 // PATypeHandles using it, the type is dead, delete it now.
305 virtual void RefCountIsZero() const {
306 abort(); // only on derived types!
311 //===----------------------------------------------------------------------===//
312 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
313 // These are defined here because they MUST be inlined, yet are dependent on
314 // the definition of the Type class. Of course Type derives from Value, which
315 // contains an AbstractTypeUser instance, so there is no good way to factor out
316 // the code. Hence this bit of uglyness.
318 // In the long term, Type should not derive from Value, allowing
319 // AbstractTypeUser.h to #include Type.h, allowing us to eliminate this
320 // nastyness entirely.
322 inline void PATypeHandle::addUser() {
323 assert(Ty && "Type Handle has a null type!");
324 if (Ty->isAbstract())
325 Ty->addAbstractTypeUser(User);
327 inline void PATypeHandle::removeUser() {
328 if (Ty->isAbstract())
329 Ty->removeAbstractTypeUser(User);
332 inline void PATypeHandle::removeUserFromConcrete() {
333 if (!Ty->isAbstract())
334 Ty->removeAbstractTypeUser(User);
337 // Define inline methods for PATypeHolder...
339 inline void PATypeHolder::addRef() {
340 if (Ty->isAbstract())
344 inline void PATypeHolder::dropRef() {
345 if (Ty->isAbstract())
349 /// get - This implements the forwarding part of the union-find algorithm for
350 /// abstract types. Before every access to the Type*, we check to see if the
351 /// type we are pointing to is forwarding to a new type. If so, we drop our
352 /// reference to the type.
354 inline const Type* PATypeHolder::get() const {
355 const Type *NewTy = Ty->getForwardedType();
356 if (!NewTy) return Ty;
357 return *const_cast<PATypeHolder*>(this) = NewTy;
362 //===----------------------------------------------------------------------===//
363 // Provide specializations of GraphTraits to be able to treat a type as a
364 // graph of sub types...
366 template <> struct GraphTraits<Type*> {
367 typedef Type NodeType;
368 typedef Type::subtype_iterator ChildIteratorType;
370 static inline NodeType *getEntryNode(Type *T) { return T; }
371 static inline ChildIteratorType child_begin(NodeType *N) {
372 return N->subtype_begin();
374 static inline ChildIteratorType child_end(NodeType *N) {
375 return N->subtype_end();
379 template <> struct GraphTraits<const Type*> {
380 typedef const Type NodeType;
381 typedef Type::subtype_iterator ChildIteratorType;
383 static inline NodeType *getEntryNode(const Type *T) { return T; }
384 static inline ChildIteratorType child_begin(NodeType *N) {
385 return N->subtype_begin();
387 static inline ChildIteratorType child_end(NodeType *N) {
388 return N->subtype_end();
392 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
393 return Ty.getPrimitiveID() == Type::PointerTyID;
396 } // End llvm namespace