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 /// bitcode 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 X86_FP80TyID, ///< 3: 80 bit floating point type (X87)
74 FP128TyID, ///< 4: 128 bit floating point type (112-bit mantissa)
75 PPC_FP128TyID, ///< 5: 128 bit floating point type (two 64-bits)
76 LabelTyID, ///< 6: Labels
78 // Derived types... see DerivedTypes.h file...
79 // Make sure FirstDerivedTyID stays up to date!!!
80 IntegerTyID, ///< 7: Arbitrary bit width integers
81 FunctionTyID, ///< 8: Functions
82 StructTyID, ///< 9: Structures
83 PackedStructTyID,///< 10: Packed Structure. This is for bitcode only
84 ArrayTyID, ///< 11: Arrays
85 PointerTyID, ///< 12: Pointers
86 OpaqueTyID, ///< 13: Opaque: type with unknown structure
87 VectorTyID, ///< 14: SIMD 'packed' format, or other vector type
89 NumTypeIDs, // Must remain as last defined ID
90 LastPrimitiveTyID = LabelTyID,
91 FirstDerivedTyID = IntegerTyID
95 TypeID ID : 8; // The current base type of this type.
96 bool Abstract : 1; // True if type contains an OpaqueType
97 unsigned SubclassData : 23; //Space for subclasses to store data
99 /// RefCount - This counts the number of PATypeHolders that are pointing to
100 /// this type. When this number falls to zero, if the type is abstract and
101 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
104 mutable unsigned RefCount;
106 const Type *getForwardedTypeInternal() const;
108 // Some Type instances are allocated as arrays, some aren't. So we provide
109 // this method to get the right kind of destruction for the type of Type.
110 void destroy() const; // const is a lie, this does "delete this"!
113 explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0),
114 RefCount(0), ForwardType(0), NumContainedTys(0),
117 assert(AbstractTypeUsers.empty() && "Abstract types remain");
120 /// Types can become nonabstract later, if they are refined.
122 inline void setAbstract(bool Val) { Abstract = Val; }
124 unsigned getRefCount() const { return RefCount; }
126 unsigned getSubclassData() const { return SubclassData; }
127 void setSubclassData(unsigned val) { SubclassData = val; }
129 /// ForwardType - This field is used to implement the union find scheme for
130 /// abstract types. When types are refined to other types, this field is set
131 /// to the more refined type. Only abstract types can be forwarded.
132 mutable const Type *ForwardType;
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 /// NumContainedTys - Keeps track of how many PATypeHandle instances there
141 /// are at the end of this type instance for the list of contained types. It
142 /// is the subclasses responsibility to set this up. Set to 0 if there are no
143 /// contained types in this type.
144 unsigned NumContainedTys;
146 /// ContainedTys - A pointer to the array of Types (PATypeHandle) contained
147 /// by this Type. For example, this includes the arguments of a function
148 /// type, the elements of a structure, the pointee of a pointer, the element
149 /// type of an array, etc. This pointer may be 0 for types that don't
150 /// contain other types (Integer, Double, Float). In general, the subclass
151 /// should arrange for space for the PATypeHandles to be included in the
152 /// allocation of the type object and set this pointer to the address of the
153 /// first element. This allows the Type class to manipulate the ContainedTys
154 /// without understanding the subclass's placement for this array. keeping
155 /// it here also allows the subtype_* members to be implemented MUCH more
156 /// efficiently, and dynamically very few types do not contain any elements.
157 PATypeHandle *ContainedTys;
160 void print(std::ostream &O) const;
161 void print(std::ostream *O) const { if (O) print(*O); }
163 /// @brief Debugging support: print to stderr
166 //===--------------------------------------------------------------------===//
167 // Property accessors for dealing with types... Some of these virtual methods
168 // are defined in private classes defined in Type.cpp for primitive types.
171 /// getTypeID - Return the type id for the type. This will return one
172 /// of the TypeID enum elements defined above.
174 inline TypeID getTypeID() const { return ID; }
176 /// getDescription - Return the string representation of the type...
177 const std::string &getDescription() const;
179 /// isInteger - True if this is an instance of IntegerType.
181 bool isInteger() const { return ID == IntegerTyID; }
183 /// isFloatingPoint - Return true if this is one of the two floating point
185 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID ||
186 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; }
188 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types.
190 bool isFPOrFPVector() const;
192 /// isAbstract - True if the type is either an Opaque type, or is a derived
193 /// type that includes an opaque type somewhere in it.
195 inline bool isAbstract() const { return Abstract; }
197 /// canLosslesslyBitCastTo - Return true if this type could be converted
198 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts
199 /// are valid for types of the same size only where no re-interpretation of
200 /// the bits is done.
201 /// @brief Determine if this type could be losslessly bitcast to Ty
202 bool canLosslesslyBitCastTo(const Type *Ty) const;
205 /// Here are some useful little methods to query what type derived types are
206 /// Note that all other types can just compare to see if this == Type::xxxTy;
208 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
209 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
211 /// isFirstClassType - Return true if the value is holdable in a register.
213 inline bool isFirstClassType() const {
214 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
215 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID;
218 /// isSized - Return true if it makes sense to take the size of this type. To
219 /// get the actual size for a particular target, it is reasonable to use the
220 /// TargetData subsystem to do this.
222 bool isSized() const {
223 // If it's a primitive, it is always sized.
224 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID)
226 // If it is not something that can have a size (e.g. a function or label),
227 // it doesn't have a size.
228 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID &&
229 ID != PackedStructTyID)
231 // If it is something that can have a size and it's concrete, it definitely
232 // has a size, otherwise we have to try harder to decide.
233 return !isAbstract() || isSizedDerivedType();
236 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a
237 /// primitive type. These are fixed by LLVM and are not target dependent.
238 /// This will return zero if the type does not have a size or is not a
241 unsigned getPrimitiveSizeInBits() const;
243 /// getForwaredType - Return the type that this type has been resolved to if
244 /// it has been resolved to anything. This is used to implement the
245 /// union-find algorithm for type resolution, and shouldn't be used by general
247 const Type *getForwardedType() const {
248 if (!ForwardType) return 0;
249 return getForwardedTypeInternal();
252 /// getVAArgsPromotedType - Return the type an argument of this type
253 /// will be promoted to if passed through a variable argument
255 const Type *getVAArgsPromotedType() const;
257 //===--------------------------------------------------------------------===//
258 // Type Iteration support
260 typedef PATypeHandle *subtype_iterator;
261 subtype_iterator subtype_begin() const { return ContainedTys; }
262 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];}
264 /// getContainedType - This method is used to implement the type iterator
265 /// (defined a the end of the file). For derived types, this returns the
266 /// types 'contained' in the derived type.
268 const Type *getContainedType(unsigned i) const {
269 assert(i < NumContainedTys && "Index out of range!");
270 return ContainedTys[i].get();
273 /// getNumContainedTypes - Return the number of types in the derived type.
275 unsigned getNumContainedTypes() const { return NumContainedTys; }
277 //===--------------------------------------------------------------------===//
278 // Static members exported by the Type class itself. Useful for getting
279 // instances of Type.
282 /// getPrimitiveType - Return a type based on an identifier.
283 static const Type *getPrimitiveType(TypeID IDNumber);
285 //===--------------------------------------------------------------------===//
286 // These are the builtin types that are always available...
288 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy;
289 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty;
290 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty;
292 /// Methods for support type inquiry through isa, cast, and dyn_cast:
293 static inline bool classof(const Type *T) { return true; }
295 void addRef() const {
296 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
300 void dropRef() const {
301 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
302 assert(RefCount && "No objects are currently referencing this object!");
304 // If this is the last PATypeHolder using this object, and there are no
305 // PATypeHandles using it, the type is dead, delete it now.
306 if (--RefCount == 0 && AbstractTypeUsers.empty())
310 /// addAbstractTypeUser - Notify an abstract type that there is a new user of
311 /// it. This function is called primarily by the PATypeHandle class.
313 void addAbstractTypeUser(AbstractTypeUser *U) const {
314 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!");
315 AbstractTypeUsers.push_back(U);
318 /// removeAbstractTypeUser - Notify an abstract type that a user of the class
319 /// no longer has a handle to the type. This function is called primarily by
320 /// the PATypeHandle class. When there are no users of the abstract type, it
321 /// is annihilated, because there is no way to get a reference to it ever
324 void removeAbstractTypeUser(AbstractTypeUser *U) const;
327 /// isSizedDerivedType - Derived types like structures and arrays are sized
328 /// iff all of the members of the type are sized as well. Since asking for
329 /// their size is relatively uncommon, move this operation out of line.
330 bool isSizedDerivedType() const;
332 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
333 virtual void typeBecameConcrete(const DerivedType *AbsTy);
336 // PromoteAbstractToConcrete - This is an internal method used to calculate
337 // change "Abstract" from true to false when types are refined.
338 void PromoteAbstractToConcrete();
339 friend class TypeMapBase;
342 //===----------------------------------------------------------------------===//
343 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
344 // These are defined here because they MUST be inlined, yet are dependent on
345 // the definition of the Type class.
347 inline void PATypeHandle::addUser() {
348 assert(Ty && "Type Handle has a null type!");
349 if (Ty->isAbstract())
350 Ty->addAbstractTypeUser(User);
352 inline void PATypeHandle::removeUser() {
353 if (Ty->isAbstract())
354 Ty->removeAbstractTypeUser(User);
357 // Define inline methods for PATypeHolder...
359 inline void PATypeHolder::addRef() {
360 if (Ty->isAbstract())
364 inline void PATypeHolder::dropRef() {
365 if (Ty->isAbstract())
370 //===----------------------------------------------------------------------===//
371 // Provide specializations of GraphTraits to be able to treat a type as a
372 // graph of sub types...
374 template <> struct GraphTraits<Type*> {
375 typedef Type NodeType;
376 typedef Type::subtype_iterator ChildIteratorType;
378 static inline NodeType *getEntryNode(Type *T) { return T; }
379 static inline ChildIteratorType child_begin(NodeType *N) {
380 return N->subtype_begin();
382 static inline ChildIteratorType child_end(NodeType *N) {
383 return N->subtype_end();
387 template <> struct GraphTraits<const Type*> {
388 typedef const Type NodeType;
389 typedef Type::subtype_iterator ChildIteratorType;
391 static inline NodeType *getEntryNode(const Type *T) { return T; }
392 static inline ChildIteratorType child_begin(NodeType *N) {
393 return N->subtype_begin();
395 static inline ChildIteratorType child_end(NodeType *N) {
396 return N->subtype_end();
400 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
401 return Ty.getTypeID() == Type::PointerTyID;
404 std::ostream &operator<<(std::ostream &OS, const Type &T);
406 } // End llvm namespace