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 //===----------------------------------------------------------------------===//
14 #include "llvm/AbstractTypeUser.h"
15 #include "llvm/Support/Casting.h"
16 #include "llvm/Support/DataTypes.h"
17 #include "llvm/Support/Streams.h"
18 #include "llvm/ADT/GraphTraits.h"
19 #include "llvm/ADT/iterator"
30 /// This file contains the declaration of the Type class. For more "Type" type
31 /// stuff, look in DerivedTypes.h.
33 /// The instances of the Type class are immutable: once they are created,
34 /// they are never changed. Also note that only one instance of a particular
35 /// type is ever created. Thus seeing if two types are equal is a matter of
36 /// doing a trivial pointer comparison. To enforce that no two equal instances
37 /// are created, Type instances can only be created via static factory methods
38 /// in class Type and in derived classes.
40 /// Once allocated, Types are never free'd, unless they are an abstract type
41 /// that is resolved to a more concrete type.
43 /// Types themself don't have a name, and can be named either by:
44 /// - using SymbolTable instance, typically from some Module,
45 /// - using convenience methods in the Module class (which uses module's
48 /// Opaque types are simple derived types with no state. There may be many
49 /// different Opaque type objects floating around, but two are only considered
50 /// identical if they are pointer equals of each other. This allows us to have
51 /// two opaque types that end up resolving to different concrete types later.
53 /// Opaque types are also kinda weird and scary and different because they have
54 /// to keep a list of uses of the type. When, through linking, parsing, or
55 /// bytecode reading, they become resolved, they need to find and update all
56 /// users of the unknown type, causing them to reference a new, more concrete
57 /// type. Opaque types are deleted when their use list dwindles to zero users.
59 /// @brief Root of type hierarchy
60 class Type : public AbstractTypeUser {
62 //===-------------------------------------------------------------------===//
63 /// Definitions of all of the base types for the Type system. Based on this
64 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
65 /// Note: If you add an element to this, you need to add an element to the
66 /// Type::getPrimitiveType function, or else things will break!
69 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
70 VoidTyID = 0, ///< 0: type with no size
71 FloatTyID, ///< 1: 32 bit floating point type
72 DoubleTyID, ///< 2: 64 bit floating point type
73 LabelTyID, ///< 3: Labels
75 // Derived types... see DerivedTypes.h file...
76 // Make sure FirstDerivedTyID stays up to date!!!
77 IntegerTyID, ///< 4: Arbitrary bit width integers
78 FunctionTyID, ///< 5: Functions
79 StructTyID, ///< 6: Structures
80 PackedStructTyID,///< 7: Packed Structure. This is for bytecode only
81 ArrayTyID, ///< 8: Arrays
82 PointerTyID, ///< 9: Pointers
83 OpaqueTyID, ///< 10: Opaque: type with unknown structure
84 VectorTyID, ///< 11: SIMD 'packed' format, or other vector type
86 NumTypeIDs, // Must remain as last defined ID
87 LastPrimitiveTyID = LabelTyID,
88 FirstDerivedTyID = IntegerTyID
92 TypeID ID : 8; // The current base type of this type.
93 bool Abstract : 1; // True if type contains an OpaqueType
94 unsigned SubclassData : 23; //Space for subclasses to store data
96 /// RefCount - This counts the number of PATypeHolders that are pointing to
97 /// this type. When this number falls to zero, if the type is abstract and
98 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
101 mutable unsigned RefCount;
103 const Type *getForwardedTypeInternal() const;
105 Type(const char *Name, TypeID id);
106 Type(TypeID id) : ID(id), Abstract(false), SubclassData(0), RefCount(0),
109 assert(AbstractTypeUsers.empty());
112 /// Types can become nonabstract later, if they are refined.
114 inline void setAbstract(bool Val) { Abstract = Val; }
116 unsigned getRefCount() const { return RefCount; }
118 unsigned getSubclassData() const { return SubclassData; }
119 void setSubclassData(unsigned val) { SubclassData = val; }
121 /// ForwardType - This field is used to implement the union find scheme for
122 /// abstract types. When types are refined to other types, this field is set
123 /// to the more refined type. Only abstract types can be forwarded.
124 mutable const Type *ForwardType;
126 /// ContainedTys - The list of types contained by this one. For example, this
127 /// includes the arguments of a function type, the elements of the structure,
128 /// the pointee of a pointer, etc. Note that keeping this vector in the Type
129 /// class wastes some space for types that do not contain anything (such as
130 /// primitive types). However, keeping it here allows the subtype_* members
131 /// to be implemented MUCH more efficiently, and dynamically very few types do
132 /// not contain any elements (most are derived).
133 std::vector<PATypeHandle> ContainedTys;
135 /// AbstractTypeUsers - Implement a list of the users that need to be notified
136 /// if I am a type, and I get resolved into a more concrete type.
138 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers;
140 void print(std::ostream &O) const;
141 void print(std::ostream *O) const { if (O) print(*O); }
143 /// @brief Debugging support: print to stderr
146 //===--------------------------------------------------------------------===//
147 // Property accessors for dealing with types... Some of these virtual methods
148 // are defined in private classes defined in Type.cpp for primitive types.
151 /// getTypeID - Return the type id for the type. This will return one
152 /// of the TypeID enum elements defined above.
154 inline TypeID getTypeID() const { return ID; }
156 /// getDescription - Return the string representation of the type...
157 const std::string &getDescription() const;
159 /// isInteger - True if this is an instance of IntegerType.
161 bool isInteger() const { return ID == IntegerTyID; }
163 /// isFloatingPoint - Return true if this is one of the two floating point
165 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; }
167 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types.
169 bool isFPOrFPVector() const;
171 /// isAbstract - True if the type is either an Opaque type, or is a derived
172 /// type that includes an opaque type somewhere in it.
174 inline bool isAbstract() const { return Abstract; }
176 /// canLosslesslyBitCastTo - Return true if this type could be converted
177 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts
178 /// are valid for types of the same size only where no re-interpretation of
179 /// the bits is done.
180 /// @brief Determine if this type could be losslessly bitcast to Ty
181 bool canLosslesslyBitCastTo(const Type *Ty) const;
184 /// Here are some useful little methods to query what type derived types are
185 /// Note that all other types can just compare to see if this == Type::xxxTy;
187 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
188 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
190 /// isFirstClassType - Return true if the value is holdable in a register.
192 inline bool isFirstClassType() const {
193 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
194 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID;
197 /// isSized - Return true if it makes sense to take the size of this type. To
198 /// get the actual size for a particular target, it is reasonable to use the
199 /// TargetData subsystem to do this.
201 bool isSized() const {
202 // If it's a primitive, it is always sized.
203 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID)
205 // If it is not something that can have a size (e.g. a function or label),
206 // it doesn't have a size.
207 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID &&
208 ID != PackedStructTyID)
210 // If it is something that can have a size and it's concrete, it definitely
211 // has a size, otherwise we have to try harder to decide.
212 return !isAbstract() || isSizedDerivedType();
215 /// getPrimitiveSize - Return the basic size of this type if it is a primitive
216 /// type. These are fixed by LLVM and are not target dependent. This will
217 /// return zero if the type does not have a size or is not a primitive type.
219 unsigned getPrimitiveSizeInBits() 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 /// getVAArgsPromotedType - Return the type an argument of this type
231 /// will be promoted to if passed through a variable argument
233 const Type *getVAArgsPromotedType() const;
235 //===--------------------------------------------------------------------===//
236 // Type Iteration support
238 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator;
239 subtype_iterator subtype_begin() const { return ContainedTys.begin(); }
240 subtype_iterator subtype_end() const { return ContainedTys.end(); }
242 /// getContainedType - This method is used to implement the type iterator
243 /// (defined a the end of the file). For derived types, this returns the
244 /// types 'contained' in the derived type.
246 const Type *getContainedType(unsigned i) const {
247 assert(i < ContainedTys.size() && "Index out of range!");
248 return ContainedTys[i];
251 /// getNumContainedTypes - Return the number of types in the derived type.
253 typedef std::vector<PATypeHandle>::size_type size_type;
254 size_type getNumContainedTypes() const { return ContainedTys.size(); }
256 //===--------------------------------------------------------------------===//
257 // Static members exported by the Type class itself. Useful for getting
258 // instances of Type.
261 /// getPrimitiveType - Return a type based on an identifier.
262 static const Type *getPrimitiveType(TypeID IDNumber);
264 //===--------------------------------------------------------------------===//
265 // These are the builtin types that are always available...
267 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy;
268 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty;
270 /// Methods for support type inquiry through isa, cast, and dyn_cast:
271 static inline bool classof(const Type *T) { return true; }
273 void addRef() const {
274 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
278 void dropRef() const {
279 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
280 assert(RefCount && "No objects are currently referencing this object!");
282 // If this is the last PATypeHolder using this object, and there are no
283 // PATypeHandles using it, the type is dead, delete it now.
284 if (--RefCount == 0 && AbstractTypeUsers.empty())
288 /// addAbstractTypeUser - Notify an abstract type that there is a new user of
289 /// it. This function is called primarily by the PATypeHandle class.
291 void addAbstractTypeUser(AbstractTypeUser *U) const {
292 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!");
293 AbstractTypeUsers.push_back(U);
296 /// removeAbstractTypeUser - Notify an abstract type that a user of the class
297 /// no longer has a handle to the type. This function is called primarily by
298 /// the PATypeHandle class. When there are no users of the abstract type, it
299 /// is annihilated, because there is no way to get a reference to it ever
302 void removeAbstractTypeUser(AbstractTypeUser *U) const;
305 /// isSizedDerivedType - Derived types like structures and arrays are sized
306 /// iff all of the members of the type are sized as well. Since asking for
307 /// their size is relatively uncommon, move this operation out of line.
308 bool isSizedDerivedType() const;
310 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
311 virtual void typeBecameConcrete(const DerivedType *AbsTy);
314 // PromoteAbstractToConcrete - This is an internal method used to calculate
315 // change "Abstract" from true to false when types are refined.
316 void PromoteAbstractToConcrete();
317 friend class TypeMapBase;
320 //===----------------------------------------------------------------------===//
321 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
322 // These are defined here because they MUST be inlined, yet are dependent on
323 // the definition of the Type class.
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 // Define inline methods for PATypeHolder...
337 inline void PATypeHolder::addRef() {
338 if (Ty->isAbstract())
342 inline void PATypeHolder::dropRef() {
343 if (Ty->isAbstract())
348 //===----------------------------------------------------------------------===//
349 // Provide specializations of GraphTraits to be able to treat a type as a
350 // graph of sub types...
352 template <> struct GraphTraits<Type*> {
353 typedef Type NodeType;
354 typedef Type::subtype_iterator ChildIteratorType;
356 static inline NodeType *getEntryNode(Type *T) { return T; }
357 static inline ChildIteratorType child_begin(NodeType *N) {
358 return N->subtype_begin();
360 static inline ChildIteratorType child_end(NodeType *N) {
361 return N->subtype_end();
365 template <> struct GraphTraits<const Type*> {
366 typedef const Type NodeType;
367 typedef Type::subtype_iterator ChildIteratorType;
369 static inline NodeType *getEntryNode(const Type *T) { return T; }
370 static inline ChildIteratorType child_begin(NodeType *N) {
371 return N->subtype_begin();
373 static inline ChildIteratorType child_end(NodeType *N) {
374 return N->subtype_end();
378 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
379 return Ty.getTypeID() == Type::PointerTyID;
382 std::ostream &operator<<(std::ostream &OS, const Type &T);
384 } // End llvm namespace