1 //===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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/ADT/GraphTraits.h"
18 #include "llvm/ADT/iterator.h"
31 /// This file contains the declaration of the Type class. For more "Type" type
32 /// stuff, look in DerivedTypes.h.
34 /// The instances of the Type class are immutable: once they are created,
35 /// they are never changed. Also note that only one instance of a particular
36 /// type is ever created. Thus seeing if two types are equal is a matter of
37 /// doing a trivial pointer comparison. To enforce that no two equal instances
38 /// are created, Type instances can only be created via static factory methods
39 /// in class Type and in derived classes.
41 /// Once allocated, Types are never free'd, unless they are an abstract type
42 /// that is resolved to a more concrete type.
44 /// Types themself don't have a name, and can be named either by:
45 /// - using SymbolTable instance, typically from some Module,
46 /// - using convenience methods in the Module class (which uses module's
49 /// Opaque types are simple derived types with no state. There may be many
50 /// different Opaque type objects floating around, but two are only considered
51 /// identical if they are pointer equals of each other. This allows us to have
52 /// two opaque types that end up resolving to different concrete types later.
54 /// Opaque types are also kinda weird and scary and different because they have
55 /// to keep a list of uses of the type. When, through linking, parsing, or
56 /// bitcode reading, they become resolved, they need to find and update all
57 /// users of the unknown type, causing them to reference a new, more concrete
58 /// type. Opaque types are deleted when their use list dwindles to zero users.
60 /// @brief Root of type hierarchy
61 class Type : public AbstractTypeUser {
63 //===-------------------------------------------------------------------===//
64 /// Definitions of all of the base types for the Type system. Based on this
65 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
66 /// Note: If you add an element to this, you need to add an element to the
67 /// Type::getPrimitiveType function, or else things will break!
70 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
71 VoidTyID = 0, ///< 0: type with no size
72 FloatTyID, ///< 1: 32 bit floating point type
73 DoubleTyID, ///< 2: 64 bit floating point type
74 X86_FP80TyID, ///< 3: 80 bit floating point type (X87)
75 FP128TyID, ///< 4: 128 bit floating point type (112-bit mantissa)
76 PPC_FP128TyID, ///< 5: 128 bit floating point type (two 64-bits)
77 LabelTyID, ///< 6: Labels
79 // Derived types... see DerivedTypes.h file...
80 // Make sure FirstDerivedTyID stays up to date!!!
81 IntegerTyID, ///< 7: Arbitrary bit width integers
82 FunctionTyID, ///< 8: Functions
83 StructTyID, ///< 9: Structures
84 ArrayTyID, ///< 10: Arrays
85 PointerTyID, ///< 11: Pointers
86 OpaqueTyID, ///< 12: Opaque: type with unknown structure
87 VectorTyID, ///< 13: 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(raw_ostream &O) const;
161 void print(std::ostream &O) const;
163 /// @brief Debugging support: print to stderr
166 /// @brief Debugging support: print to stderr (use type names from context
168 void dump(const Module *Context) const;
170 //===--------------------------------------------------------------------===//
171 // Property accessors for dealing with types... Some of these virtual methods
172 // are defined in private classes defined in Type.cpp for primitive types.
175 /// getTypeID - Return the type id for the type. This will return one
176 /// of the TypeID enum elements defined above.
178 inline TypeID getTypeID() const { return ID; }
180 /// getDescription - Return the string representation of the type.
181 std::string getDescription() const;
183 /// isInteger - True if this is an instance of IntegerType.
185 bool isInteger() const { return ID == IntegerTyID; }
187 /// isIntOrIntVector - Return true if this is an integer type or a vector of
190 bool isIntOrIntVector() const;
192 /// isFloatingPoint - Return true if this is one of the two floating point
194 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID ||
195 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; }
197 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types.
199 bool isFPOrFPVector() const;
201 /// isAbstract - True if the type is either an Opaque type, or is a derived
202 /// type that includes an opaque type somewhere in it.
204 inline bool isAbstract() const { return Abstract; }
206 /// canLosslesslyBitCastTo - Return true if this type could be converted
207 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts
208 /// are valid for types of the same size only where no re-interpretation of
209 /// the bits is done.
210 /// @brief Determine if this type could be losslessly bitcast to Ty
211 bool canLosslesslyBitCastTo(const Type *Ty) const;
214 /// Here are some useful little methods to query what type derived types are
215 /// Note that all other types can just compare to see if this == Type::xxxTy;
217 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
218 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
220 /// isFirstClassType - Return true if the type is "first class", meaning it
221 /// is a valid type for a Value.
223 inline bool isFirstClassType() const {
224 // There are more first-class kinds than non-first-class kinds, so a
225 // negative test is simpler than a positive one.
226 return ID != FunctionTyID && ID != VoidTyID && ID != OpaqueTyID;
229 /// isSingleValueType - Return true if the type is a valid type for a
230 /// virtual register in codegen. This includes all first-class types
231 /// except struct and array types.
233 inline bool isSingleValueType() const {
234 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
235 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID;
238 /// isAggregateType - Return true if the type is an aggregate type. This
239 /// means it is valid as the first operand of an insertvalue or
240 /// extractvalue instruction. This includes struct and array types, but
241 /// does not include vector types.
243 inline bool isAggregateType() const {
244 return ID == StructTyID || ID == ArrayTyID;
247 /// isSized - Return true if it makes sense to take the size of this type. To
248 /// get the actual size for a particular target, it is reasonable to use the
249 /// TargetData subsystem to do this.
251 bool isSized() const {
252 // If it's a primitive, it is always sized.
253 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID)
255 // If it is not something that can have a size (e.g. a function or label),
256 // it doesn't have a size.
257 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID)
259 // If it is something that can have a size and it's concrete, it definitely
260 // has a size, otherwise we have to try harder to decide.
261 return !isAbstract() || isSizedDerivedType();
264 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a
265 /// primitive type. These are fixed by LLVM and are not target dependent.
266 /// This will return zero if the type does not have a size or is not a
269 unsigned getPrimitiveSizeInBits() const;
271 /// getFPMantissaWidth - Return the width of the mantissa of this type. This
272 /// is only valid on scalar floating point types. If the FP type does not
273 /// have a stable mantissa (e.g. ppc long double), this method returns -1.
274 int getFPMantissaWidth() const {
275 assert(isFloatingPoint() && "Not a floating point type!");
276 if (ID == FloatTyID) return 24;
277 if (ID == DoubleTyID) return 53;
278 if (ID == X86_FP80TyID) return 64;
279 if (ID == FP128TyID) return 113;
280 assert(ID == PPC_FP128TyID && "unknown fp type");
284 /// getForwardedType - Return the type that this type has been resolved to if
285 /// it has been resolved to anything. This is used to implement the
286 /// union-find algorithm for type resolution, and shouldn't be used by general
288 const Type *getForwardedType() const {
289 if (!ForwardType) return 0;
290 return getForwardedTypeInternal();
293 /// getVAArgsPromotedType - Return the type an argument of this type
294 /// will be promoted to if passed through a variable argument
296 const Type *getVAArgsPromotedType() const;
298 //===--------------------------------------------------------------------===//
299 // Type Iteration support
301 typedef PATypeHandle *subtype_iterator;
302 subtype_iterator subtype_begin() const { return ContainedTys; }
303 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];}
305 /// getContainedType - This method is used to implement the type iterator
306 /// (defined a the end of the file). For derived types, this returns the
307 /// types 'contained' in the derived type.
309 const Type *getContainedType(unsigned i) const {
310 assert(i < NumContainedTys && "Index out of range!");
311 return ContainedTys[i].get();
314 /// getNumContainedTypes - Return the number of types in the derived type.
316 unsigned getNumContainedTypes() const { return NumContainedTys; }
318 //===--------------------------------------------------------------------===//
319 // Static members exported by the Type class itself. Useful for getting
320 // instances of Type.
323 /// getPrimitiveType - Return a type based on an identifier.
324 static const Type *getPrimitiveType(TypeID IDNumber);
326 //===--------------------------------------------------------------------===//
327 // These are the builtin types that are always available...
329 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy, *EmptyStructTy;
330 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty;
331 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty;
333 /// Methods for support type inquiry through isa, cast, and dyn_cast:
334 static inline bool classof(const Type *) { return true; }
336 void addRef() const {
337 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
341 void dropRef() const {
342 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
343 assert(RefCount && "No objects are currently referencing this object!");
345 // If this is the last PATypeHolder using this object, and there are no
346 // PATypeHandles using it, the type is dead, delete it now.
347 if (--RefCount == 0 && AbstractTypeUsers.empty())
351 /// addAbstractTypeUser - Notify an abstract type that there is a new user of
352 /// it. This function is called primarily by the PATypeHandle class.
354 void addAbstractTypeUser(AbstractTypeUser *U) const {
355 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!");
356 AbstractTypeUsers.push_back(U);
359 /// removeAbstractTypeUser - Notify an abstract type that a user of the class
360 /// no longer has a handle to the type. This function is called primarily by
361 /// the PATypeHandle class. When there are no users of the abstract type, it
362 /// is annihilated, because there is no way to get a reference to it ever
365 void removeAbstractTypeUser(AbstractTypeUser *U) const;
368 /// isSizedDerivedType - Derived types like structures and arrays are sized
369 /// iff all of the members of the type are sized as well. Since asking for
370 /// their size is relatively uncommon, move this operation out of line.
371 bool isSizedDerivedType() const;
373 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
374 virtual void typeBecameConcrete(const DerivedType *AbsTy);
377 // PromoteAbstractToConcrete - This is an internal method used to calculate
378 // change "Abstract" from true to false when types are refined.
379 void PromoteAbstractToConcrete();
380 friend class TypeMapBase;
383 //===----------------------------------------------------------------------===//
384 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
385 // These are defined here because they MUST be inlined, yet are dependent on
386 // the definition of the Type class.
388 inline void PATypeHandle::addUser() {
389 assert(Ty && "Type Handle has a null type!");
390 if (Ty->isAbstract())
391 Ty->addAbstractTypeUser(User);
393 inline void PATypeHandle::removeUser() {
394 if (Ty->isAbstract())
395 Ty->removeAbstractTypeUser(User);
398 // Define inline methods for PATypeHolder.
400 /// get - This implements the forwarding part of the union-find algorithm for
401 /// abstract types. Before every access to the Type*, we check to see if the
402 /// type we are pointing to is forwarding to a new type. If so, we drop our
403 /// reference to the type.
405 inline Type* PATypeHolder::get() const {
406 const Type *NewTy = Ty->getForwardedType();
407 if (!NewTy) return const_cast<Type*>(Ty);
408 return *const_cast<PATypeHolder*>(this) = NewTy;
411 inline void PATypeHolder::addRef() {
412 assert(Ty && "Type Holder has a null type!");
413 if (Ty->isAbstract())
417 inline void PATypeHolder::dropRef() {
418 if (Ty->isAbstract())
423 //===----------------------------------------------------------------------===//
424 // Provide specializations of GraphTraits to be able to treat a type as a
425 // graph of sub types...
427 template <> struct GraphTraits<Type*> {
428 typedef Type NodeType;
429 typedef Type::subtype_iterator ChildIteratorType;
431 static inline NodeType *getEntryNode(Type *T) { return T; }
432 static inline ChildIteratorType child_begin(NodeType *N) {
433 return N->subtype_begin();
435 static inline ChildIteratorType child_end(NodeType *N) {
436 return N->subtype_end();
440 template <> struct GraphTraits<const Type*> {
441 typedef const Type NodeType;
442 typedef Type::subtype_iterator ChildIteratorType;
444 static inline NodeType *getEntryNode(const Type *T) { return T; }
445 static inline ChildIteratorType child_begin(NodeType *N) {
446 return N->subtype_begin();
448 static inline ChildIteratorType child_end(NodeType *N) {
449 return N->subtype_end();
453 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
454 return Ty.getTypeID() == Type::PointerTyID;
457 std::ostream &operator<<(std::ostream &OS, const Type &T);
458 raw_ostream &operator<<(raw_ostream &OS, const Type &T);
460 } // End llvm namespace