Type.h revision 795daece23cdc66bc7c16e9a2043dd4a4d0bbfc0
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; 29class Module; 30 31/// This file contains the declaration of the Type class. For more "Type" type 32/// stuff, look in DerivedTypes.h. 33/// 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. 40/// 41/// Once allocated, Types are never free'd, unless they are an abstract type 42/// that is resolved to a more concrete type. 43/// 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 47/// SymbolTable too). 48/// 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. 53/// 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. 59/// 60/// @brief Root of type hierarchy 61class Type : public AbstractTypeUser { 62public: 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! 68 /// 69 enum TypeID { 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 78 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 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(raw_ostream &O) const; 161 void print(std::ostream &O) const; 162 163 /// @brief Debugging support: print to stderr 164 void dump() const; 165 166 /// @brief Debugging support: print to stderr (use type names from context 167 /// module). 168 void dump(const Module *Context) const; 169 170 //===--------------------------------------------------------------------===// 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. 173 // 174 175 /// getTypeID - Return the type id for the type. This will return one 176 /// of the TypeID enum elements defined above. 177 /// 178 inline TypeID getTypeID() const { return ID; } 179 180 /// getDescription - Return the string representation of the type... 181 const std::string &getDescription() const; 182 183 /// isInteger - True if this is an instance of IntegerType. 184 /// 185 bool isInteger() const { return ID == IntegerTyID; } 186 187 /// isIntOrIntVector - Return true if this is an integer type or a vector of 188 /// integer types. 189 /// 190 bool isIntOrIntVector() const; 191 192 /// isFloatingPoint - Return true if this is one of the two floating point 193 /// types 194 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID || 195 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; } 196 197 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types. 198 /// 199 bool isFPOrFPVector() const; 200 201 /// isAbstract - True if the type is either an Opaque type, or is a derived 202 /// type that includes an opaque type somewhere in it. 203 /// 204 inline bool isAbstract() const { return Abstract; } 205 206 /// 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; 212 213 214 /// 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; 216 /// 217 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 218 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 219 220 /// isFirstClassType - Return true if the type is "first class", meaning it 221 /// is a valid type for a Value. 222 /// 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; 227 } 228 229 /// 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. 232 /// 233 inline bool isSingleValueType() const { 234 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 235 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID; 236 } 237 238 /// 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. 242 /// 243 inline bool isAggregateType() const { 244 return ID == StructTyID || ID == ArrayTyID; 245 } 246 247 /// 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. 250 /// 251 bool isSized() const { 252 // If it's a primitive, it is always sized. 253 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID) 254 return true; 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) 258 return false; 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(); 262 } 263 264 /// 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 267 /// primitive type. 268 /// 269 unsigned getPrimitiveSizeInBits() const; 270 271 /// 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"); 281 return -1; 282 } 283 284 /// 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 287 /// purpose clients. 288 const Type *getForwardedType() const { 289 if (!ForwardType) return 0; 290 return getForwardedTypeInternal(); 291 } 292 293 /// getVAArgsPromotedType - Return the type an argument of this type 294 /// will be promoted to if passed through a variable argument 295 /// function. 296 const Type *getVAArgsPromotedType() const; 297 298 //===--------------------------------------------------------------------===// 299 // Type Iteration support 300 // 301 typedef PATypeHandle *subtype_iterator; 302 subtype_iterator subtype_begin() const { return ContainedTys; } 303 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];} 304 305 /// 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. 308 /// 309 const Type *getContainedType(unsigned i) const { 310 assert(i < NumContainedTys && "Index out of range!"); 311 return ContainedTys[i].get(); 312 } 313 314 /// getNumContainedTypes - Return the number of types in the derived type. 315 /// 316 unsigned getNumContainedTypes() const { return NumContainedTys; } 317 318 //===--------------------------------------------------------------------===// 319 // Static members exported by the Type class itself. Useful for getting 320 // instances of Type. 321 // 322 323 /// getPrimitiveType - Return a type based on an identifier. 324 static const Type *getPrimitiveType(TypeID IDNumber); 325 326 //===--------------------------------------------------------------------===// 327 // These are the builtin types that are always available... 328 // 329 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy; 330 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty; 331 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty; 332 333 /// Methods for support type inquiry through isa, cast, and dyn_cast: 334 static inline bool classof(const Type *) { return true; } 335 336 void addRef() const { 337 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 338 ++RefCount; 339 } 340 341 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!"); 344 345 // 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()) 348 this->destroy(); 349 } 350 351 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 352 /// it. This function is called primarily by the PATypeHandle class. 353 /// 354 void addAbstractTypeUser(AbstractTypeUser *U) const { 355 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 356 AbstractTypeUsers.push_back(U); 357 } 358 359 /// 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 363 /// again. 364 /// 365 void removeAbstractTypeUser(AbstractTypeUser *U) const; 366 367private: 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; 372 373 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 374 virtual void typeBecameConcrete(const DerivedType *AbsTy); 375 376protected: 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; 381}; 382 383//===----------------------------------------------------------------------===// 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. 387// 388inline void PATypeHandle::addUser() { 389 assert(Ty && "Type Handle has a null type!"); 390 if (Ty->isAbstract()) 391 Ty->addAbstractTypeUser(User); 392} 393inline void PATypeHandle::removeUser() { 394 if (Ty->isAbstract()) 395 Ty->removeAbstractTypeUser(User); 396} 397 398// Define inline methods for PATypeHolder. 399 400/// 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. 404/// 405inline 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; 409} 410 411inline void PATypeHolder::addRef() { 412 assert(Ty && "Type Holder has a null type!"); 413 if (Ty->isAbstract()) 414 Ty->addRef(); 415} 416 417inline void PATypeHolder::dropRef() { 418 if (Ty->isAbstract()) 419 Ty->dropRef(); 420} 421 422 423//===----------------------------------------------------------------------===// 424// Provide specializations of GraphTraits to be able to treat a type as a 425// graph of sub types... 426 427template <> struct GraphTraits<Type*> { 428 typedef Type NodeType; 429 typedef Type::subtype_iterator ChildIteratorType; 430 431 static inline NodeType *getEntryNode(Type *T) { return T; } 432 static inline ChildIteratorType child_begin(NodeType *N) { 433 return N->subtype_begin(); 434 } 435 static inline ChildIteratorType child_end(NodeType *N) { 436 return N->subtype_end(); 437 } 438}; 439 440template <> struct GraphTraits<const Type*> { 441 typedef const Type NodeType; 442 typedef Type::subtype_iterator ChildIteratorType; 443 444 static inline NodeType *getEntryNode(const Type *T) { return T; } 445 static inline ChildIteratorType child_begin(NodeType *N) { 446 return N->subtype_begin(); 447 } 448 static inline ChildIteratorType child_end(NodeType *N) { 449 return N->subtype_end(); 450 } 451}; 452 453template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 454 return Ty.getTypeID() == Type::PointerTyID; 455} 456 457std::ostream &operator<<(std::ostream &OS, const Type &T); 458raw_ostream &operator<<(raw_ostream &OS, const Type &T); 459 460} // End llvm namespace 461 462#endif 463