Type.h revision 7353404303d84169bb8f422698949be79957eb1a
1//===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// 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/ADT/GraphTraits.h" 18#include "llvm/ADT/iterator.h" 19#include <string> 20#include <vector> 21 22namespace llvm { 23 24class DerivedType; 25class PointerType; 26class IntegerType; 27class TypeMapBase; 28class raw_ostream; 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 ArrayTyID, ///< 10: Arrays 84 PointerTyID, ///< 11: Pointers 85 OpaqueTyID, ///< 12: Opaque: type with unknown structure 86 VectorTyID, ///< 13: SIMD 'packed' format, or other vector type 87 88 NumTypeIDs, // Must remain as last defined ID 89 LastPrimitiveTyID = LabelTyID, 90 FirstDerivedTyID = IntegerTyID 91 }; 92 93private: 94 TypeID ID : 8; // The current base type of this type. 95 bool Abstract : 1; // True if type contains an OpaqueType 96 unsigned SubclassData : 23; //Space for subclasses to store data 97 98 /// RefCount - This counts the number of PATypeHolders that are pointing to 99 /// this type. When this number falls to zero, if the type is abstract and 100 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 101 /// derived types. 102 /// 103 mutable unsigned RefCount; 104 105 const Type *getForwardedTypeInternal() const; 106 107 // Some Type instances are allocated as arrays, some aren't. So we provide 108 // this method to get the right kind of destruction for the type of Type. 109 void destroy() const; // const is a lie, this does "delete this"! 110 111protected: 112 explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0), 113 RefCount(0), ForwardType(0), NumContainedTys(0), 114 ContainedTys(0) {} 115 virtual ~Type() { 116 assert(AbstractTypeUsers.empty() && "Abstract types remain"); 117 } 118 119 /// Types can become nonabstract later, if they are refined. 120 /// 121 inline void setAbstract(bool Val) { Abstract = Val; } 122 123 unsigned getRefCount() const { return RefCount; } 124 125 unsigned getSubclassData() const { return SubclassData; } 126 void setSubclassData(unsigned val) { SubclassData = val; } 127 128 /// ForwardType - This field is used to implement the union find scheme for 129 /// abstract types. When types are refined to other types, this field is set 130 /// to the more refined type. Only abstract types can be forwarded. 131 mutable const Type *ForwardType; 132 133 134 /// AbstractTypeUsers - Implement a list of the users that need to be notified 135 /// if I am a type, and I get resolved into a more concrete type. 136 /// 137 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 138 139 /// NumContainedTys - Keeps track of how many PATypeHandle instances there 140 /// are at the end of this type instance for the list of contained types. It 141 /// is the subclasses responsibility to set this up. Set to 0 if there are no 142 /// contained types in this type. 143 unsigned NumContainedTys; 144 145 /// ContainedTys - A pointer to the array of Types (PATypeHandle) contained 146 /// by this Type. For example, this includes the arguments of a function 147 /// type, the elements of a structure, the pointee of a pointer, the element 148 /// type of an array, etc. This pointer may be 0 for types that don't 149 /// contain other types (Integer, Double, Float). In general, the subclass 150 /// should arrange for space for the PATypeHandles to be included in the 151 /// allocation of the type object and set this pointer to the address of the 152 /// first element. This allows the Type class to manipulate the ContainedTys 153 /// without understanding the subclass's placement for this array. keeping 154 /// it here also allows the subtype_* members to be implemented MUCH more 155 /// efficiently, and dynamically very few types do not contain any elements. 156 PATypeHandle *ContainedTys; 157 158public: 159 void print(raw_ostream &O) const; 160 void print(std::ostream &O) const; 161 162 /// @brief Debugging support: print to stderr 163 void dump() const; 164 165 //===--------------------------------------------------------------------===// 166 // Property accessors for dealing with types... Some of these virtual methods 167 // are defined in private classes defined in Type.cpp for primitive types. 168 // 169 170 /// getTypeID - Return the type id for the type. This will return one 171 /// of the TypeID enum elements defined above. 172 /// 173 inline TypeID getTypeID() const { return ID; } 174 175 /// getDescription - Return the string representation of the type... 176 const std::string &getDescription() const; 177 178 /// isInteger - True if this is an instance of IntegerType. 179 /// 180 bool isInteger() const { return ID == IntegerTyID; } 181 182 /// isIntOrIntVector - Return true if this is an integer type or a vector of 183 /// integer types. 184 /// 185 bool isIntOrIntVector() const; 186 187 /// isFloatingPoint - Return true if this is one of the two floating point 188 /// types 189 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID || 190 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; } 191 192 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types. 193 /// 194 bool isFPOrFPVector() const; 195 196 /// isAbstract - True if the type is either an Opaque type, or is a derived 197 /// type that includes an opaque type somewhere in it. 198 /// 199 inline bool isAbstract() const { return Abstract; } 200 201 /// canLosslesslyBitCastTo - Return true if this type could be converted 202 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts 203 /// are valid for types of the same size only where no re-interpretation of 204 /// the bits is done. 205 /// @brief Determine if this type could be losslessly bitcast to Ty 206 bool canLosslesslyBitCastTo(const Type *Ty) const; 207 208 209 /// Here are some useful little methods to query what type derived types are 210 /// Note that all other types can just compare to see if this == Type::xxxTy; 211 /// 212 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 213 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 214 215 /// isFirstClassType - Return true if the type is "first class", meaning it 216 /// is a valid type for a Value. 217 /// 218 inline bool isFirstClassType() const { 219 // There are more first-class kinds than non-first-class kinds, so a 220 // negative test is simpler than a positive one. 221 return ID != FunctionTyID && ID != VoidTyID && ID != OpaqueTyID; 222 } 223 224 /// isSingleValueType - Return true if the type is a valid type for a 225 /// virtual register in codegen. This includes all first-class types 226 /// except struct and array types. 227 /// 228 inline bool isSingleValueType() const { 229 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 230 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID; 231 } 232 233 /// isAggregateType - Return true if the type is an aggregate type. This 234 /// means it is valid as the first operand of an insertvalue or 235 /// extractvalue instruction. This includes struct and array types, but 236 /// does not include vector types. 237 /// 238 inline bool isAggregateType() const { 239 return ID == StructTyID || ID == ArrayTyID; 240 } 241 242 /// isSized - Return true if it makes sense to take the size of this type. To 243 /// get the actual size for a particular target, it is reasonable to use the 244 /// TargetData subsystem to do this. 245 /// 246 bool isSized() const { 247 // If it's a primitive, it is always sized. 248 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID) 249 return true; 250 // If it is not something that can have a size (e.g. a function or label), 251 // it doesn't have a size. 252 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID) 253 return false; 254 // If it is something that can have a size and it's concrete, it definitely 255 // has a size, otherwise we have to try harder to decide. 256 return !isAbstract() || isSizedDerivedType(); 257 } 258 259 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a 260 /// primitive type. These are fixed by LLVM and are not target dependent. 261 /// This will return zero if the type does not have a size or is not a 262 /// primitive type. 263 /// 264 unsigned getPrimitiveSizeInBits() const; 265 266 /// getFPMantissaWidth - Return the width of the mantissa of this type. This 267 /// is only valid on scalar floating point types. If the FP type does not 268 /// have a stable mantissa (e.g. ppc long double), this method returns -1. 269 int getFPMantissaWidth() const { 270 assert(isFloatingPoint() && "Not a floating point type!"); 271 if (ID == FloatTyID) return 24; 272 if (ID == DoubleTyID) return 53; 273 if (ID == X86_FP80TyID) return 64; 274 if (ID == FP128TyID) return 113; 275 assert(ID == PPC_FP128TyID && "unknown fp type"); 276 return -1; 277 } 278 279 /// getForwardedType - Return the type that this type has been resolved to if 280 /// it has been resolved to anything. This is used to implement the 281 /// union-find algorithm for type resolution, and shouldn't be used by general 282 /// purpose clients. 283 const Type *getForwardedType() const { 284 if (!ForwardType) return 0; 285 return getForwardedTypeInternal(); 286 } 287 288 /// getVAArgsPromotedType - Return the type an argument of this type 289 /// will be promoted to if passed through a variable argument 290 /// function. 291 const Type *getVAArgsPromotedType() const; 292 293 //===--------------------------------------------------------------------===// 294 // Type Iteration support 295 // 296 typedef PATypeHandle *subtype_iterator; 297 subtype_iterator subtype_begin() const { return ContainedTys; } 298 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];} 299 300 /// getContainedType - This method is used to implement the type iterator 301 /// (defined a the end of the file). For derived types, this returns the 302 /// types 'contained' in the derived type. 303 /// 304 const Type *getContainedType(unsigned i) const { 305 assert(i < NumContainedTys && "Index out of range!"); 306 return ContainedTys[i].get(); 307 } 308 309 /// getNumContainedTypes - Return the number of types in the derived type. 310 /// 311 unsigned getNumContainedTypes() const { return NumContainedTys; } 312 313 //===--------------------------------------------------------------------===// 314 // Static members exported by the Type class itself. Useful for getting 315 // instances of Type. 316 // 317 318 /// getPrimitiveType - Return a type based on an identifier. 319 static const Type *getPrimitiveType(TypeID IDNumber); 320 321 //===--------------------------------------------------------------------===// 322 // These are the builtin types that are always available... 323 // 324 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy; 325 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty; 326 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty; 327 328 /// Methods for support type inquiry through isa, cast, and dyn_cast: 329 static inline bool classof(const Type *) { return true; } 330 331 void addRef() const { 332 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 333 ++RefCount; 334 } 335 336 void dropRef() const { 337 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 338 assert(RefCount && "No objects are currently referencing this object!"); 339 340 // If this is the last PATypeHolder using this object, and there are no 341 // PATypeHandles using it, the type is dead, delete it now. 342 if (--RefCount == 0 && AbstractTypeUsers.empty()) 343 this->destroy(); 344 } 345 346 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 347 /// it. This function is called primarily by the PATypeHandle class. 348 /// 349 void addAbstractTypeUser(AbstractTypeUser *U) const { 350 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 351 AbstractTypeUsers.push_back(U); 352 } 353 354 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 355 /// no longer has a handle to the type. This function is called primarily by 356 /// the PATypeHandle class. When there are no users of the abstract type, it 357 /// is annihilated, because there is no way to get a reference to it ever 358 /// again. 359 /// 360 void removeAbstractTypeUser(AbstractTypeUser *U) const; 361 362private: 363 /// isSizedDerivedType - Derived types like structures and arrays are sized 364 /// iff all of the members of the type are sized as well. Since asking for 365 /// their size is relatively uncommon, move this operation out of line. 366 bool isSizedDerivedType() const; 367 368 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 369 virtual void typeBecameConcrete(const DerivedType *AbsTy); 370 371protected: 372 // PromoteAbstractToConcrete - This is an internal method used to calculate 373 // change "Abstract" from true to false when types are refined. 374 void PromoteAbstractToConcrete(); 375 friend class TypeMapBase; 376}; 377 378//===----------------------------------------------------------------------===// 379// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 380// These are defined here because they MUST be inlined, yet are dependent on 381// the definition of the Type class. 382// 383inline void PATypeHandle::addUser() { 384 assert(Ty && "Type Handle has a null type!"); 385 if (Ty->isAbstract()) 386 Ty->addAbstractTypeUser(User); 387} 388inline void PATypeHandle::removeUser() { 389 if (Ty->isAbstract()) 390 Ty->removeAbstractTypeUser(User); 391} 392 393// Define inline methods for PATypeHolder. 394 395/// get - This implements the forwarding part of the union-find algorithm for 396/// abstract types. Before every access to the Type*, we check to see if the 397/// type we are pointing to is forwarding to a new type. If so, we drop our 398/// reference to the type. 399/// 400inline Type* PATypeHolder::get() const { 401 const Type *NewTy = Ty->getForwardedType(); 402 if (!NewTy) return const_cast<Type*>(Ty); 403 return *const_cast<PATypeHolder*>(this) = NewTy; 404} 405 406inline void PATypeHolder::addRef() { 407 assert(Ty && "Type Holder has a null type!"); 408 if (Ty->isAbstract()) 409 Ty->addRef(); 410} 411 412inline void PATypeHolder::dropRef() { 413 if (Ty->isAbstract()) 414 Ty->dropRef(); 415} 416 417 418//===----------------------------------------------------------------------===// 419// Provide specializations of GraphTraits to be able to treat a type as a 420// graph of sub types... 421 422template <> struct GraphTraits<Type*> { 423 typedef Type NodeType; 424 typedef Type::subtype_iterator ChildIteratorType; 425 426 static inline NodeType *getEntryNode(Type *T) { return T; } 427 static inline ChildIteratorType child_begin(NodeType *N) { 428 return N->subtype_begin(); 429 } 430 static inline ChildIteratorType child_end(NodeType *N) { 431 return N->subtype_end(); 432 } 433}; 434 435template <> struct GraphTraits<const Type*> { 436 typedef const Type NodeType; 437 typedef Type::subtype_iterator ChildIteratorType; 438 439 static inline NodeType *getEntryNode(const Type *T) { return T; } 440 static inline ChildIteratorType child_begin(NodeType *N) { 441 return N->subtype_begin(); 442 } 443 static inline ChildIteratorType child_end(NodeType *N) { 444 return N->subtype_end(); 445 } 446}; 447 448template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 449 return Ty.getTypeID() == Type::PointerTyID; 450} 451 452std::ostream &operator<<(std::ostream &OS, const Type &T); 453raw_ostream &operator<<(raw_ostream &OS, const Type &T); 454 455} // End llvm namespace 456 457#endif 458