Type.h revision ef1af7d6d5be039e7eea46f8f3a2720fb5a1a153
1//===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 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. 7// 8//===----------------------------------------------------------------------===// 9 10 11#ifndef LLVM_TYPE_H 12#define LLVM_TYPE_H 13 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" 20#include <string> 21#include <vector> 22 23namespace llvm { 24 25class DerivedType; 26class PointerType; 27class IntegerType; 28class TypeMapBase; 29 30/// This file contains the declaration of the Type class. For more "Type" type 31/// stuff, look in DerivedTypes.h. 32/// 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. 39/// 40/// Once allocated, Types are never free'd, unless they are an abstract type 41/// that is resolved to a more concrete type. 42/// 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 46/// SymbolTable too). 47/// 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. 52/// 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. 58/// 59/// @brief Root of type hierarchy 60class Type : public AbstractTypeUser { 61public: 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! 67 /// 68 enum TypeID { 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 77 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 88 89 NumTypeIDs, // Must remain as last defined ID 90 LastPrimitiveTyID = LabelTyID, 91 FirstDerivedTyID = IntegerTyID 92 }; 93 94private: 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 98 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 102 /// derived types. 103 /// 104 mutable unsigned RefCount; 105 106 const Type *getForwardedTypeInternal() const; 107 108 // 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"! 111 112protected: 113 explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0), 114 RefCount(0), ForwardType(0), NumContainedTys(0), 115 ContainedTys(0) {} 116 virtual ~Type() { 117 assert(AbstractTypeUsers.empty() && "Abstract types remain"); 118 } 119 120 /// Types can become nonabstract later, if they are refined. 121 /// 122 inline void setAbstract(bool Val) { Abstract = Val; } 123 124 unsigned getRefCount() const { return RefCount; } 125 126 unsigned getSubclassData() const { return SubclassData; } 127 void setSubclassData(unsigned val) { SubclassData = val; } 128 129 /// 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; 133 134 135 /// 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. 137 /// 138 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 139 140 /// 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; 145 146 /// 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; 158 159public: 160 void print(std::ostream &O) const; 161 void print(std::ostream *O) const { if (O) print(*O); } 162 163 /// @brief Debugging support: print to stderr 164 void dump() const; 165 166 //===--------------------------------------------------------------------===// 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. 169 // 170 171 /// getTypeID - Return the type id for the type. This will return one 172 /// of the TypeID enum elements defined above. 173 /// 174 inline TypeID getTypeID() const { return ID; } 175 176 /// getDescription - Return the string representation of the type... 177 const std::string &getDescription() const; 178 179 /// isInteger - True if this is an instance of IntegerType. 180 /// 181 bool isInteger() const { return ID == IntegerTyID; } 182 183 /// isIntOrIntVector - Return true if this is an integer type or a vector of 184 /// integer types. 185 /// 186 bool isIntOrIntVector() const; 187 188 /// isFloatingPoint - Return true if this is one of the two floating point 189 /// types 190 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID || 191 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; } 192 193 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types. 194 /// 195 bool isFPOrFPVector() const; 196 197 /// isAbstract - True if the type is either an Opaque type, or is a derived 198 /// type that includes an opaque type somewhere in it. 199 /// 200 inline bool isAbstract() const { return Abstract; } 201 202 /// canLosslesslyBitCastTo - Return true if this type could be converted 203 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts 204 /// are valid for types of the same size only where no re-interpretation of 205 /// the bits is done. 206 /// @brief Determine if this type could be losslessly bitcast to Ty 207 bool canLosslesslyBitCastTo(const Type *Ty) const; 208 209 210 /// Here are some useful little methods to query what type derived types are 211 /// Note that all other types can just compare to see if this == Type::xxxTy; 212 /// 213 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 214 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 215 216 /// isFirstClassType - Return true if the value is holdable in a register. 217 /// 218 inline bool isFirstClassType() const { 219 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 220 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID; 221 } 222 223 /// isSized - Return true if it makes sense to take the size of this type. To 224 /// get the actual size for a particular target, it is reasonable to use the 225 /// TargetData subsystem to do this. 226 /// 227 bool isSized() const { 228 // If it's a primitive, it is always sized. 229 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID) 230 return true; 231 // If it is not something that can have a size (e.g. a function or label), 232 // it doesn't have a size. 233 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID && 234 ID != PackedStructTyID) 235 return false; 236 // If it is something that can have a size and it's concrete, it definitely 237 // has a size, otherwise we have to try harder to decide. 238 return !isAbstract() || isSizedDerivedType(); 239 } 240 241 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a 242 /// primitive type. These are fixed by LLVM and are not target dependent. 243 /// This will return zero if the type does not have a size or is not a 244 /// primitive type. 245 /// 246 unsigned getPrimitiveSizeInBits() const; 247 248 /// getForwaredType - Return the type that this type has been resolved to if 249 /// it has been resolved to anything. This is used to implement the 250 /// union-find algorithm for type resolution, and shouldn't be used by general 251 /// purpose clients. 252 const Type *getForwardedType() const { 253 if (!ForwardType) return 0; 254 return getForwardedTypeInternal(); 255 } 256 257 /// getVAArgsPromotedType - Return the type an argument of this type 258 /// will be promoted to if passed through a variable argument 259 /// function. 260 const Type *getVAArgsPromotedType() const; 261 262 //===--------------------------------------------------------------------===// 263 // Type Iteration support 264 // 265 typedef PATypeHandle *subtype_iterator; 266 subtype_iterator subtype_begin() const { return ContainedTys; } 267 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];} 268 269 /// getContainedType - This method is used to implement the type iterator 270 /// (defined a the end of the file). For derived types, this returns the 271 /// types 'contained' in the derived type. 272 /// 273 const Type *getContainedType(unsigned i) const { 274 assert(i < NumContainedTys && "Index out of range!"); 275 return ContainedTys[i].get(); 276 } 277 278 /// getNumContainedTypes - Return the number of types in the derived type. 279 /// 280 unsigned getNumContainedTypes() const { return NumContainedTys; } 281 282 //===--------------------------------------------------------------------===// 283 // Static members exported by the Type class itself. Useful for getting 284 // instances of Type. 285 // 286 287 /// getPrimitiveType - Return a type based on an identifier. 288 static const Type *getPrimitiveType(TypeID IDNumber); 289 290 //===--------------------------------------------------------------------===// 291 // These are the builtin types that are always available... 292 // 293 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy; 294 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty; 295 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty; 296 297 /// Methods for support type inquiry through isa, cast, and dyn_cast: 298 static inline bool classof(const Type *T) { return true; } 299 300 void addRef() const { 301 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 302 ++RefCount; 303 } 304 305 void dropRef() const { 306 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 307 assert(RefCount && "No objects are currently referencing this object!"); 308 309 // If this is the last PATypeHolder using this object, and there are no 310 // PATypeHandles using it, the type is dead, delete it now. 311 if (--RefCount == 0 && AbstractTypeUsers.empty()) 312 this->destroy(); 313 } 314 315 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 316 /// it. This function is called primarily by the PATypeHandle class. 317 /// 318 void addAbstractTypeUser(AbstractTypeUser *U) const { 319 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 320 AbstractTypeUsers.push_back(U); 321 } 322 323 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 324 /// no longer has a handle to the type. This function is called primarily by 325 /// the PATypeHandle class. When there are no users of the abstract type, it 326 /// is annihilated, because there is no way to get a reference to it ever 327 /// again. 328 /// 329 void removeAbstractTypeUser(AbstractTypeUser *U) const; 330 331private: 332 /// isSizedDerivedType - Derived types like structures and arrays are sized 333 /// iff all of the members of the type are sized as well. Since asking for 334 /// their size is relatively uncommon, move this operation out of line. 335 bool isSizedDerivedType() const; 336 337 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 338 virtual void typeBecameConcrete(const DerivedType *AbsTy); 339 340protected: 341 // PromoteAbstractToConcrete - This is an internal method used to calculate 342 // change "Abstract" from true to false when types are refined. 343 void PromoteAbstractToConcrete(); 344 friend class TypeMapBase; 345}; 346 347//===----------------------------------------------------------------------===// 348// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 349// These are defined here because they MUST be inlined, yet are dependent on 350// the definition of the Type class. 351// 352inline void PATypeHandle::addUser() { 353 assert(Ty && "Type Handle has a null type!"); 354 if (Ty->isAbstract()) 355 Ty->addAbstractTypeUser(User); 356} 357inline void PATypeHandle::removeUser() { 358 if (Ty->isAbstract()) 359 Ty->removeAbstractTypeUser(User); 360} 361 362// Define inline methods for PATypeHolder... 363 364inline void PATypeHolder::addRef() { 365 if (Ty->isAbstract()) 366 Ty->addRef(); 367} 368 369inline void PATypeHolder::dropRef() { 370 if (Ty->isAbstract()) 371 Ty->dropRef(); 372} 373 374 375//===----------------------------------------------------------------------===// 376// Provide specializations of GraphTraits to be able to treat a type as a 377// graph of sub types... 378 379template <> struct GraphTraits<Type*> { 380 typedef Type NodeType; 381 typedef Type::subtype_iterator ChildIteratorType; 382 383 static inline NodeType *getEntryNode(Type *T) { return T; } 384 static inline ChildIteratorType child_begin(NodeType *N) { 385 return N->subtype_begin(); 386 } 387 static inline ChildIteratorType child_end(NodeType *N) { 388 return N->subtype_end(); 389 } 390}; 391 392template <> struct GraphTraits<const Type*> { 393 typedef const Type NodeType; 394 typedef Type::subtype_iterator ChildIteratorType; 395 396 static inline NodeType *getEntryNode(const Type *T) { return T; } 397 static inline ChildIteratorType child_begin(NodeType *N) { 398 return N->subtype_begin(); 399 } 400 static inline ChildIteratorType child_end(NodeType *N) { 401 return N->subtype_end(); 402 } 403}; 404 405template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 406 return Ty.getTypeID() == Type::PointerTyID; 407} 408 409std::ostream &operator<<(std::ostream &OS, const Type &T); 410 411} // End llvm namespace 412 413#endif 414