Type.h revision 42a75517250017a52afb03a0ade03cbd49559fe5
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 ArrayType; 26class DerivedType; 27class FunctionType; 28class OpaqueType; 29class PointerType; 30class StructType; 31class PackedType; 32class TypeMapBase; 33 34/// This file contains the declaration of the Type class. For more "Type" type 35/// stuff, look in DerivedTypes.h. 36/// 37/// The instances of the Type class are immutable: once they are created, 38/// they are never changed. Also note that only one instance of a particular 39/// type is ever created. Thus seeing if two types are equal is a matter of 40/// doing a trivial pointer comparison. To enforce that no two equal instances 41/// are created, Type instances can only be created via static factory methods 42/// in class Type and in derived classes. 43/// 44/// Once allocated, Types are never free'd, unless they are an abstract type 45/// that is resolved to a more concrete type. 46/// 47/// Types themself don't have a name, and can be named either by: 48/// - using SymbolTable instance, typically from some Module, 49/// - using convenience methods in the Module class (which uses module's 50/// SymbolTable too). 51/// 52/// Opaque types are simple derived types with no state. There may be many 53/// different Opaque type objects floating around, but two are only considered 54/// identical if they are pointer equals of each other. This allows us to have 55/// two opaque types that end up resolving to different concrete types later. 56/// 57/// Opaque types are also kinda weird and scary and different because they have 58/// to keep a list of uses of the type. When, through linking, parsing, or 59/// bytecode reading, they become resolved, they need to find and update all 60/// users of the unknown type, causing them to reference a new, more concrete 61/// type. Opaque types are deleted when their use list dwindles to zero users. 62/// 63/// @brief Root of type hierarchy 64class Type : public AbstractTypeUser { 65public: 66 ///===-------------------------------------------------------------------===// 67 /// Definitions of all of the base types for the Type system. Based on this 68 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h) 69 /// Note: If you add an element to this, you need to add an element to the 70 /// Type::getPrimitiveType function, or else things will break! 71 /// 72 enum TypeID { 73 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date 74 VoidTyID = 0, ///< 0: type with no size 75 FloatTyID, ///< 1: 32 bit floating point type 76 DoubleTyID, ///< 2: 64 bit floating point type 77 LabelTyID, ///< 3: Labels 78 79 // Derived types... see DerivedTypes.h file... 80 // Make sure FirstDerivedTyID stays up to date!!! 81 IntegerTyID, ///< 4: Arbitrary bit width integers 82 FunctionTyID, ///< 5: Functions 83 StructTyID, ///< 6: Structures 84 PackedStructTyID,///< 7: Packed Structure. This is for bytecode only 85 ArrayTyID, ///< 8: Arrays 86 PointerTyID, ///< 9: Pointers 87 OpaqueTyID, ///< 10: Opaque: type with unknown structure 88 PackedTyID, ///< 11: SIMD 'packed' format, or other vector type 89 90 NumTypeIDs, // Must remain as last defined ID 91 LastPrimitiveTyID = LabelTyID, 92 FirstDerivedTyID = IntegerTyID 93 }; 94 95private: 96 TypeID ID : 8; // The current base type of this type. 97 bool Abstract : 1; // True if type contains an OpaqueType 98 unsigned SubclassData : 23; //Space for subclasses to store data 99 100 /// RefCount - This counts the number of PATypeHolders that are pointing to 101 /// this type. When this number falls to zero, if the type is abstract and 102 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 103 /// derived types. 104 /// 105 mutable unsigned RefCount; 106 107 const Type *getForwardedTypeInternal() const; 108protected: 109 Type(const char *Name, TypeID id); 110 Type(TypeID id) : ID(id), Abstract(false), SubclassData(0), RefCount(0), 111 ForwardType(0) {} 112 virtual ~Type() { 113 assert(AbstractTypeUsers.empty()); 114 } 115 116 /// Types can become nonabstract later, if they are refined. 117 /// 118 inline void setAbstract(bool Val) { Abstract = Val; } 119 120 unsigned getRefCount() const { return RefCount; } 121 122 unsigned getSubclassData() const { return SubclassData; } 123 void setSubclassData(unsigned val) { SubclassData = val; } 124 125 /// ForwardType - This field is used to implement the union find scheme for 126 /// abstract types. When types are refined to other types, this field is set 127 /// to the more refined type. Only abstract types can be forwarded. 128 mutable const Type *ForwardType; 129 130 /// ContainedTys - The list of types contained by this one. For example, this 131 /// includes the arguments of a function type, the elements of the structure, 132 /// the pointee of a pointer, etc. Note that keeping this vector in the Type 133 /// class wastes some space for types that do not contain anything (such as 134 /// primitive types). However, keeping it here allows the subtype_* members 135 /// to be implemented MUCH more efficiently, and dynamically very few types do 136 /// not contain any elements (most are derived). 137 std::vector<PATypeHandle> ContainedTys; 138 139 /// AbstractTypeUsers - Implement a list of the users that need to be notified 140 /// if I am a type, and I get resolved into a more concrete type. 141 /// 142 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 143public: 144 void print(std::ostream &O) const; 145 void print(std::ostream *O) const { if (O) print(*O); } 146 147 /// @brief Debugging support: print to stderr 148 void dump() const; 149 150 //===--------------------------------------------------------------------===// 151 // Property accessors for dealing with types... Some of these virtual methods 152 // are defined in private classes defined in Type.cpp for primitive types. 153 // 154 155 /// getTypeID - Return the type id for the type. This will return one 156 /// of the TypeID enum elements defined above. 157 /// 158 inline TypeID getTypeID() const { return ID; } 159 160 /// getDescription - Return the string representation of the type... 161 const std::string &getDescription() const; 162 163 /// isInteger - True if this is an instance of IntegerType. 164 /// 165 bool isInteger() const { return ID == IntegerTyID; } 166 167 /// isFloatingPoint - Return true if this is one of the two floating point 168 /// types 169 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; } 170 171 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types. 172 /// 173 bool isFPOrFPVector() const; 174 175 /// isAbstract - True if the type is either an Opaque type, or is a derived 176 /// type that includes an opaque type somewhere in it. 177 /// 178 inline bool isAbstract() const { return Abstract; } 179 180 /// canLosslesslyBitCastTo - Return true if this type could be converted 181 /// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts 182 /// are valid for types of the same size only where no re-interpretation of 183 /// the bits is done. 184 /// @brief Determine if this type could be losslessly bitcast to Ty 185 bool canLosslesslyBitCastTo(const Type *Ty) const; 186 187 188 /// Here are some useful little methods to query what type derived types are 189 /// Note that all other types can just compare to see if this == Type::xxxTy; 190 /// 191 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 192 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 193 194 /// isFirstClassType - Return true if the value is holdable in a register. 195 /// 196 inline bool isFirstClassType() const { 197 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 198 ID == IntegerTyID || ID == PointerTyID || ID == PackedTyID; 199 } 200 201 /// isSized - Return true if it makes sense to take the size of this type. To 202 /// get the actual size for a particular target, it is reasonable to use the 203 /// TargetData subsystem to do this. 204 /// 205 bool isSized() const { 206 // If it's a primitive, it is always sized. 207 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID) 208 return true; 209 // If it is not something that can have a size (e.g. a function or label), 210 // it doesn't have a size. 211 if (ID != StructTyID && ID != ArrayTyID && ID != PackedTyID && 212 ID != PackedStructTyID) 213 return false; 214 // If it is something that can have a size and it's concrete, it definitely 215 // has a size, otherwise we have to try harder to decide. 216 return !isAbstract() || isSizedDerivedType(); 217 } 218 219 /// getPrimitiveSize - Return the basic size of this type if it is a primitive 220 /// type. These are fixed by LLVM and are not target dependent. This will 221 /// return zero if the type does not have a size or is not a primitive type. 222 /// 223 unsigned getPrimitiveSizeInBits() const; 224 225 /// getIntegerTypeMask - Return a bitmask with ones set for all of the bits 226 /// that can be set by an unsigned version of this type. This is 0xFF for 227 /// sbyte/ubyte, 0xFFFF for shorts, etc. 228 uint64_t getIntegerTypeMask() const { 229 assert(isInteger() && "This only works for integer types!"); 230 return ~uint64_t(0UL) >> (64-getPrimitiveSizeInBits()); 231 } 232 233 /// getForwaredType - Return the type that this type has been resolved to if 234 /// it has been resolved to anything. This is used to implement the 235 /// union-find algorithm for type resolution, and shouldn't be used by general 236 /// purpose clients. 237 const Type *getForwardedType() const { 238 if (!ForwardType) return 0; 239 return getForwardedTypeInternal(); 240 } 241 242 /// getVAArgsPromotedType - Return the type an argument of this type 243 /// will be promoted to if passed through a variable argument 244 /// function. 245 const Type *getVAArgsPromotedType() const { 246 if (ID == IntegerTyID && getSubclassData() < 32) 247 return Type::Int32Ty; 248 else if (ID == FloatTyID) 249 return Type::DoubleTy; 250 else 251 return this; 252 } 253 254 //===--------------------------------------------------------------------===// 255 // Type Iteration support 256 // 257 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator; 258 subtype_iterator subtype_begin() const { return ContainedTys.begin(); } 259 subtype_iterator subtype_end() const { return ContainedTys.end(); } 260 261 /// getContainedType - This method is used to implement the type iterator 262 /// (defined a the end of the file). For derived types, this returns the 263 /// types 'contained' in the derived type. 264 /// 265 const Type *getContainedType(unsigned i) const { 266 assert(i < ContainedTys.size() && "Index out of range!"); 267 return ContainedTys[i]; 268 } 269 270 /// getNumContainedTypes - Return the number of types in the derived type. 271 /// 272 typedef std::vector<PATypeHandle>::size_type size_type; 273 size_type getNumContainedTypes() const { return ContainedTys.size(); } 274 275 //===--------------------------------------------------------------------===// 276 // Static members exported by the Type class itself. Useful for getting 277 // instances of Type. 278 // 279 280 /// getPrimitiveType - Return a type based on an identifier. 281 static const Type *getPrimitiveType(TypeID IDNumber); 282 283 //===--------------------------------------------------------------------===// 284 // These are the builtin types that are always available... 285 // 286 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy; 287 static const Type *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty; 288 289 /// Methods for support type inquiry through isa, cast, and dyn_cast: 290 static inline bool classof(const Type *T) { return true; } 291 292 void addRef() const { 293 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 294 ++RefCount; 295 } 296 297 void dropRef() const { 298 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 299 assert(RefCount && "No objects are currently referencing this object!"); 300 301 // If this is the last PATypeHolder using this object, and there are no 302 // PATypeHandles using it, the type is dead, delete it now. 303 if (--RefCount == 0 && AbstractTypeUsers.empty()) 304 delete this; 305 } 306 307 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 308 /// it. This function is called primarily by the PATypeHandle class. 309 /// 310 void addAbstractTypeUser(AbstractTypeUser *U) const { 311 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 312 AbstractTypeUsers.push_back(U); 313 } 314 315 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 316 /// no longer has a handle to the type. This function is called primarily by 317 /// the PATypeHandle class. When there are no users of the abstract type, it 318 /// is annihilated, because there is no way to get a reference to it ever 319 /// again. 320 /// 321 void removeAbstractTypeUser(AbstractTypeUser *U) const; 322 323private: 324 /// isSizedDerivedType - Derived types like structures and arrays are sized 325 /// iff all of the members of the type are sized as well. Since asking for 326 /// their size is relatively uncommon, move this operation out of line. 327 bool isSizedDerivedType() const; 328 329 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 330 virtual void typeBecameConcrete(const DerivedType *AbsTy); 331 332protected: 333 // PromoteAbstractToConcrete - This is an internal method used to calculate 334 // change "Abstract" from true to false when types are refined. 335 void PromoteAbstractToConcrete(); 336 friend class TypeMapBase; 337}; 338 339//===----------------------------------------------------------------------===// 340// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 341// These are defined here because they MUST be inlined, yet are dependent on 342// the definition of the Type class. 343// 344inline void PATypeHandle::addUser() { 345 assert(Ty && "Type Handle has a null type!"); 346 if (Ty->isAbstract()) 347 Ty->addAbstractTypeUser(User); 348} 349inline void PATypeHandle::removeUser() { 350 if (Ty->isAbstract()) 351 Ty->removeAbstractTypeUser(User); 352} 353 354// Define inline methods for PATypeHolder... 355 356inline void PATypeHolder::addRef() { 357 if (Ty->isAbstract()) 358 Ty->addRef(); 359} 360 361inline void PATypeHolder::dropRef() { 362 if (Ty->isAbstract()) 363 Ty->dropRef(); 364} 365 366 367//===----------------------------------------------------------------------===// 368// Provide specializations of GraphTraits to be able to treat a type as a 369// graph of sub types... 370 371template <> struct GraphTraits<Type*> { 372 typedef Type NodeType; 373 typedef Type::subtype_iterator ChildIteratorType; 374 375 static inline NodeType *getEntryNode(Type *T) { return T; } 376 static inline ChildIteratorType child_begin(NodeType *N) { 377 return N->subtype_begin(); 378 } 379 static inline ChildIteratorType child_end(NodeType *N) { 380 return N->subtype_end(); 381 } 382}; 383 384template <> struct GraphTraits<const Type*> { 385 typedef const Type NodeType; 386 typedef Type::subtype_iterator ChildIteratorType; 387 388 static inline NodeType *getEntryNode(const Type *T) { return T; } 389 static inline ChildIteratorType child_begin(NodeType *N) { 390 return N->subtype_begin(); 391 } 392 static inline ChildIteratorType child_end(NodeType *N) { 393 return N->subtype_end(); 394 } 395}; 396 397template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 398 return Ty.getTypeID() == Type::PointerTyID; 399} 400 401std::ostream &operator<<(std::ostream &OS, const Type &T); 402 403} // End llvm namespace 404 405#endif 406