Type.h revision 6f2c64d70aad5328a843a6f6a6547ada69ead33b
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/System/Atomic.h" 18#include "llvm/ADT/GraphTraits.h" 19#include "llvm/ADT/iterator.h" 20#include <string> 21#include <vector> 22 23namespace llvm { 24 25class DerivedType; 26class PointerType; 27class IntegerType; 28class TypeMapBase; 29class raw_ostream; 30class Module; 31 32/// This file contains the declaration of the Type class. For more "Type" type 33/// stuff, look in DerivedTypes.h. 34/// 35/// The instances of the Type class are immutable: once they are created, 36/// they are never changed. Also note that only one instance of a particular 37/// type is ever created. Thus seeing if two types are equal is a matter of 38/// doing a trivial pointer comparison. To enforce that no two equal instances 39/// are created, Type instances can only be created via static factory methods 40/// in class Type and in derived classes. 41/// 42/// Once allocated, Types are never free'd, unless they are an abstract type 43/// that is resolved to a more concrete type. 44/// 45/// Types themself don't have a name, and can be named either by: 46/// - using SymbolTable instance, typically from some Module, 47/// - using convenience methods in the Module class (which uses module's 48/// SymbolTable too). 49/// 50/// Opaque types are simple derived types with no state. There may be many 51/// different Opaque type objects floating around, but two are only considered 52/// identical if they are pointer equals of each other. This allows us to have 53/// two opaque types that end up resolving to different concrete types later. 54/// 55/// Opaque types are also kinda weird and scary and different because they have 56/// to keep a list of uses of the type. When, through linking, parsing, or 57/// bitcode reading, they become resolved, they need to find and update all 58/// users of the unknown type, causing them to reference a new, more concrete 59/// type. Opaque types are deleted when their use list dwindles to zero users. 60/// 61/// @brief Root of type hierarchy 62class Type : public AbstractTypeUser { 63public: 64 //===-------------------------------------------------------------------===// 65 /// Definitions of all of the base types for the Type system. Based on this 66 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h) 67 /// Note: If you add an element to this, you need to add an element to the 68 /// Type::getPrimitiveType function, or else things will break! 69 /// 70 enum TypeID { 71 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date 72 VoidTyID = 0, ///< 0: type with no size 73 FloatTyID, ///< 1: 32 bit floating point type 74 DoubleTyID, ///< 2: 64 bit floating point type 75 X86_FP80TyID, ///< 3: 80 bit floating point type (X87) 76 FP128TyID, ///< 4: 128 bit floating point type (112-bit mantissa) 77 PPC_FP128TyID, ///< 5: 128 bit floating point type (two 64-bits) 78 LabelTyID, ///< 6: Labels 79 MetadataTyID, ///< 7: Metadata 80 81 // Derived types... see DerivedTypes.h file... 82 // Make sure FirstDerivedTyID stays up to date!!! 83 IntegerTyID, ///< 8: Arbitrary bit width integers 84 FunctionTyID, ///< 9: Functions 85 StructTyID, ///< 10: Structures 86 ArrayTyID, ///< 11: Arrays 87 PointerTyID, ///< 12: Pointers 88 OpaqueTyID, ///< 13: Opaque: type with unknown structure 89 VectorTyID, ///< 14: SIMD 'packed' format, or other vector type 90 91 NumTypeIDs, // Must remain as last defined ID 92 LastPrimitiveTyID = LabelTyID, 93 FirstDerivedTyID = IntegerTyID 94 }; 95 96private: 97 TypeID ID : 8; // The current base type of this type. 98 bool Abstract : 1; // True if type contains an OpaqueType 99 unsigned SubclassData : 23; //Space for subclasses to store data 100 101 /// RefCount - This counts the number of PATypeHolders that are pointing to 102 /// this type. When this number falls to zero, if the type is abstract and 103 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 104 /// derived types. 105 /// 106 mutable sys::cas_flag RefCount; 107 108 const Type *getForwardedTypeInternal() const; 109 110 // Some Type instances are allocated as arrays, some aren't. So we provide 111 // this method to get the right kind of destruction for the type of Type. 112 void destroy() const; // const is a lie, this does "delete this"! 113 114protected: 115 explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0), 116 RefCount(0), ForwardType(0), NumContainedTys(0), 117 ContainedTys(0) {} 118 virtual ~Type() { 119 assert(AbstractTypeUsers.empty() && "Abstract types remain"); 120 } 121 122 /// Types can become nonabstract later, if they are refined. 123 /// 124 inline void setAbstract(bool Val) { Abstract = Val; } 125 126 unsigned getRefCount() const { return RefCount; } 127 128 unsigned getSubclassData() const { return SubclassData; } 129 void setSubclassData(unsigned val) { SubclassData = val; } 130 131 /// ForwardType - This field is used to implement the union find scheme for 132 /// abstract types. When types are refined to other types, this field is set 133 /// to the more refined type. Only abstract types can be forwarded. 134 mutable const Type *ForwardType; 135 136 137 /// AbstractTypeUsers - Implement a list of the users that need to be notified 138 /// if I am a type, and I get resolved into a more concrete type. 139 /// 140 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 141 142 /// NumContainedTys - Keeps track of how many PATypeHandle instances there 143 /// are at the end of this type instance for the list of contained types. It 144 /// is the subclasses responsibility to set this up. Set to 0 if there are no 145 /// contained types in this type. 146 unsigned NumContainedTys; 147 148 /// ContainedTys - A pointer to the array of Types (PATypeHandle) contained 149 /// by this Type. For example, this includes the arguments of a function 150 /// type, the elements of a structure, the pointee of a pointer, the element 151 /// type of an array, etc. This pointer may be 0 for types that don't 152 /// contain other types (Integer, Double, Float). In general, the subclass 153 /// should arrange for space for the PATypeHandles to be included in the 154 /// allocation of the type object and set this pointer to the address of the 155 /// first element. This allows the Type class to manipulate the ContainedTys 156 /// without understanding the subclass's placement for this array. keeping 157 /// it here also allows the subtype_* members to be implemented MUCH more 158 /// efficiently, and dynamically very few types do not contain any elements. 159 PATypeHandle *ContainedTys; 160 161public: 162 void print(raw_ostream &O) const; 163 void print(std::ostream &O) const; 164 165 /// @brief Debugging support: print to stderr 166 void dump() const; 167 168 /// @brief Debugging support: print to stderr (use type names from context 169 /// module). 170 void dump(const Module *Context) const; 171 172 //===--------------------------------------------------------------------===// 173 // Property accessors for dealing with types... Some of these virtual methods 174 // are defined in private classes defined in Type.cpp for primitive types. 175 // 176 177 /// getTypeID - Return the type id for the type. This will return one 178 /// of the TypeID enum elements defined above. 179 /// 180 inline TypeID getTypeID() const { return ID; } 181 182 /// getDescription - Return the string representation of the type. 183 std::string getDescription() const; 184 185 /// isInteger - True if this is an instance of IntegerType. 186 /// 187 bool isInteger() const { return ID == IntegerTyID; } 188 189 /// isIntOrIntVector - Return true if this is an integer type or a vector of 190 /// integer types. 191 /// 192 bool isIntOrIntVector() const; 193 194 /// isFloatingPoint - Return true if this is one of the two floating point 195 /// types 196 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID || 197 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; } 198 199 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types. 200 /// 201 bool isFPOrFPVector() const; 202 203 /// isAbstract - True if the type is either an Opaque type, or is a derived 204 /// type that includes an opaque type somewhere in it. 205 /// 206 inline bool isAbstract() const { return Abstract; } 207 208 /// canLosslesslyBitCastTo - Return true if this type could be converted 209 /// with a lossless BitCast to type 'Ty'. For example, i8* to i32*. BitCasts 210 /// are valid for types of the same size only where no re-interpretation of 211 /// the bits is done. 212 /// @brief Determine if this type could be losslessly bitcast to Ty 213 bool canLosslesslyBitCastTo(const Type *Ty) const; 214 215 216 /// Here are some useful little methods to query what type derived types are 217 /// Note that all other types can just compare to see if this == Type::xxxTy; 218 /// 219 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 220 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 221 222 /// isFirstClassType - Return true if the type is "first class", meaning it 223 /// is a valid type for a Value. 224 /// 225 inline bool isFirstClassType() const { 226 // There are more first-class kinds than non-first-class kinds, so a 227 // negative test is simpler than a positive one. 228 return ID != FunctionTyID && ID != VoidTyID && ID != OpaqueTyID; 229 } 230 231 /// isSingleValueType - Return true if the type is a valid type for a 232 /// virtual register in codegen. This includes all first-class types 233 /// except struct and array types. 234 /// 235 inline bool isSingleValueType() const { 236 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 237 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID; 238 } 239 240 /// isAggregateType - Return true if the type is an aggregate type. This 241 /// means it is valid as the first operand of an insertvalue or 242 /// extractvalue instruction. This includes struct and array types, but 243 /// does not include vector types. 244 /// 245 inline bool isAggregateType() const { 246 return ID == StructTyID || ID == ArrayTyID; 247 } 248 249 /// isSized - Return true if it makes sense to take the size of this type. To 250 /// get the actual size for a particular target, it is reasonable to use the 251 /// TargetData subsystem to do this. 252 /// 253 bool isSized() const { 254 // If it's a primitive, it is always sized. 255 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID) 256 return true; 257 // If it is not something that can have a size (e.g. a function or label), 258 // it doesn't have a size. 259 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID) 260 return false; 261 // If it is something that can have a size and it's concrete, it definitely 262 // has a size, otherwise we have to try harder to decide. 263 return !isAbstract() || isSizedDerivedType(); 264 } 265 266 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a 267 /// primitive type. These are fixed by LLVM and are not target dependent. 268 /// This will return zero if the type does not have a size or is not a 269 /// primitive type. 270 /// 271 unsigned getPrimitiveSizeInBits() const; 272 273 /// getScalarSizeInBits - If this is a vector type, return the 274 /// getPrimitiveSizeInBits value for the element type. Otherwise return the 275 /// getPrimitiveSizeInBits value for this type. 276 unsigned getScalarSizeInBits() const; 277 278 /// getFPMantissaWidth - Return the width of the mantissa of this type. This 279 /// is only valid on floating point types. If the FP type does not 280 /// have a stable mantissa (e.g. ppc long double), this method returns -1. 281 int getFPMantissaWidth() const; 282 283 /// getForwardedType - Return the type that this type has been resolved to if 284 /// it has been resolved to anything. This is used to implement the 285 /// union-find algorithm for type resolution, and shouldn't be used by general 286 /// purpose clients. 287 const Type *getForwardedType() const { 288 if (!ForwardType) return 0; 289 return getForwardedTypeInternal(); 290 } 291 292 /// getVAArgsPromotedType - Return the type an argument of this type 293 /// will be promoted to if passed through a variable argument 294 /// function. 295 const Type *getVAArgsPromotedType() const; 296 297 /// getScalarType - If this is a vector type, return the element type, 298 /// otherwise return this. 299 const Type *getScalarType() const; 300 301 //===--------------------------------------------------------------------===// 302 // Type Iteration support 303 // 304 typedef PATypeHandle *subtype_iterator; 305 subtype_iterator subtype_begin() const { return ContainedTys; } 306 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];} 307 308 /// getContainedType - This method is used to implement the type iterator 309 /// (defined a the end of the file). For derived types, this returns the 310 /// types 'contained' in the derived type. 311 /// 312 const Type *getContainedType(unsigned i) const { 313 assert(i < NumContainedTys && "Index out of range!"); 314 return ContainedTys[i].get(); 315 } 316 317 /// getNumContainedTypes - Return the number of types in the derived type. 318 /// 319 unsigned getNumContainedTypes() const { return NumContainedTys; } 320 321 //===--------------------------------------------------------------------===// 322 // Static members exported by the Type class itself. Useful for getting 323 // instances of Type. 324 // 325 326 /// getPrimitiveType - Return a type based on an identifier. 327 static const Type *getPrimitiveType(TypeID IDNumber); 328 329 //===--------------------------------------------------------------------===// 330 // These are the builtin types that are always available... 331 // 332 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy, *MetadataTy; 333 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty; 334 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty; 335 336 /// Methods for support type inquiry through isa, cast, and dyn_cast: 337 static inline bool classof(const Type *) { return true; } 338 339 void addRef() const { 340 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 341 sys::AtomicIncrement(&RefCount); 342 } 343 344 void dropRef() const { 345 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 346 assert(RefCount && "No objects are currently referencing this object!"); 347 348 // If this is the last PATypeHolder using this object, and there are no 349 // PATypeHandles using it, the type is dead, delete it now. 350 sys::cas_flag OldCount = sys::AtomicDecrement(&RefCount); 351 if (OldCount == 0 && AbstractTypeUsers.empty()) 352 this->destroy(); 353 } 354 355 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 356 /// it. This function is called primarily by the PATypeHandle class. 357 /// 358 void addAbstractTypeUser(AbstractTypeUser *U) const; 359 360 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 361 /// no longer has a handle to the type. This function is called primarily by 362 /// the PATypeHandle class. When there are no users of the abstract type, it 363 /// is annihilated, because there is no way to get a reference to it ever 364 /// again. 365 /// 366 void removeAbstractTypeUser(AbstractTypeUser *U) const; 367 368 /// getPointerTo - Return a pointer to the current type. This is equivalent 369 /// to PointerType::get(Foo, AddrSpace). 370 PointerType *getPointerTo(unsigned AddrSpace = 0) const; 371 372private: 373 /// isSizedDerivedType - Derived types like structures and arrays are sized 374 /// iff all of the members of the type are sized as well. Since asking for 375 /// their size is relatively uncommon, move this operation out of line. 376 bool isSizedDerivedType() const; 377 378 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 379 virtual void typeBecameConcrete(const DerivedType *AbsTy); 380 381protected: 382 // PromoteAbstractToConcrete - This is an internal method used to calculate 383 // change "Abstract" from true to false when types are refined. 384 void PromoteAbstractToConcrete(); 385 friend class TypeMapBase; 386}; 387 388//===----------------------------------------------------------------------===// 389// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 390// These are defined here because they MUST be inlined, yet are dependent on 391// the definition of the Type class. 392// 393inline void PATypeHandle::addUser() { 394 assert(Ty && "Type Handle has a null type!"); 395 if (Ty->isAbstract()) 396 Ty->addAbstractTypeUser(User); 397} 398inline void PATypeHandle::removeUser() { 399 if (Ty->isAbstract()) 400 Ty->removeAbstractTypeUser(User); 401} 402 403// Define inline methods for PATypeHolder. 404 405/// get - This implements the forwarding part of the union-find algorithm for 406/// abstract types. Before every access to the Type*, we check to see if the 407/// type we are pointing to is forwarding to a new type. If so, we drop our 408/// reference to the type. 409/// 410inline Type* PATypeHolder::get() const { 411 const Type *NewTy = Ty->getForwardedType(); 412 if (!NewTy) return const_cast<Type*>(Ty); 413 return *const_cast<PATypeHolder*>(this) = NewTy; 414} 415 416inline void PATypeHolder::addRef() { 417 assert(Ty && "Type Holder has a null type!"); 418 if (Ty->isAbstract()) 419 Ty->addRef(); 420} 421 422inline void PATypeHolder::dropRef() { 423 if (Ty->isAbstract()) 424 Ty->dropRef(); 425} 426 427 428//===----------------------------------------------------------------------===// 429// Provide specializations of GraphTraits to be able to treat a type as a 430// graph of sub types... 431 432template <> struct GraphTraits<Type*> { 433 typedef Type NodeType; 434 typedef Type::subtype_iterator ChildIteratorType; 435 436 static inline NodeType *getEntryNode(Type *T) { return T; } 437 static inline ChildIteratorType child_begin(NodeType *N) { 438 return N->subtype_begin(); 439 } 440 static inline ChildIteratorType child_end(NodeType *N) { 441 return N->subtype_end(); 442 } 443}; 444 445template <> struct GraphTraits<const Type*> { 446 typedef const Type NodeType; 447 typedef Type::subtype_iterator ChildIteratorType; 448 449 static inline NodeType *getEntryNode(const Type *T) { return T; } 450 static inline ChildIteratorType child_begin(NodeType *N) { 451 return N->subtype_begin(); 452 } 453 static inline ChildIteratorType child_end(NodeType *N) { 454 return N->subtype_end(); 455 } 456}; 457 458template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 459 return Ty.getTypeID() == Type::PointerTyID; 460} 461 462std::ostream &operator<<(std::ostream &OS, const Type &T); 463raw_ostream &operator<<(raw_ostream &OS, const Type &T); 464 465} // End llvm namespace 466 467#endif 468