Type.h revision e1d6799661f9b7fe7f5729005f9ff4afb9df9592
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// This file contains the declaration of the Type class. For more "Type" type 11// stuff, look in DerivedTypes.h. 12// 13// Note that instances of the Type class are immutable: once they are created, 14// they are never changed. Also note that only one instance of a particular 15// type is ever created. Thus seeing if two types are equal is a matter of 16// doing a trivial pointer comparison. 17// 18// Types, once allocated, are never free'd, unless they are an abstract type 19// that is resolved to a more concrete type. 20// 21// Opaque types are simple derived types with no state. There may be many 22// different Opaque type objects floating around, but two are only considered 23// identical if they are pointer equals of each other. This allows us to have 24// two opaque types that end up resolving to different concrete types later. 25// 26// Opaque types are also kinda wierd and scary and different because they have 27// to keep a list of uses of the type. When, through linking, parsing, or 28// bytecode reading, they become resolved, they need to find and update all 29// users of the unknown type, causing them to reference a new, more concrete 30// type. Opaque types are deleted when their use list dwindles to zero users. 31// 32//===----------------------------------------------------------------------===// 33 34#ifndef LLVM_TYPE_H 35#define LLVM_TYPE_H 36 37#include "AbstractTypeUser.h" 38#include "Support/Casting.h" 39#include "Support/GraphTraits.h" 40#include "Support/iterator" 41#include <vector> 42 43namespace llvm { 44 45class ArrayType; 46class DerivedType; 47class FunctionType; 48class OpaqueType; 49class PointerType; 50class StructType; 51class SymbolTable; 52 53struct Type { 54 ///===-------------------------------------------------------------------===// 55 /// Definitions of all of the base types for the Type system. Based on this 56 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h) 57 /// Note: If you add an element to this, you need to add an element to the 58 /// Type::getPrimitiveType function, or else things will break! 59 /// 60 enum TypeID { 61 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date 62 VoidTyID = 0 , BoolTyID, // 0, 1: Basics... 63 UByteTyID , SByteTyID, // 2, 3: 8 bit types... 64 UShortTyID , ShortTyID, // 4, 5: 16 bit types... 65 UIntTyID , IntTyID, // 6, 7: 32 bit types... 66 ULongTyID , LongTyID, // 8, 9: 64 bit types... 67 FloatTyID , DoubleTyID, // 10,11: Floating point types... 68 LabelTyID , // 12 : Labels... 69 70 // Derived types... see DerivedTypes.h file... 71 // Make sure FirstDerivedTyID stays up to date!!! 72 FunctionTyID , StructTyID, // Functions... Structs... 73 ArrayTyID , PointerTyID, // Array... pointer... 74 OpaqueTyID, // Opaque type instances... 75 //PackedTyID , // SIMD 'packed' format... TODO 76 //... 77 78 NumTypeIDs, // Must remain as last defined ID 79 LastPrimitiveTyID = LabelTyID, 80 FirstDerivedTyID = FunctionTyID, 81 }; 82 83private: 84 TypeID ID : 8; // The current base type of this type. 85 bool Abstract; // True if type contains an OpaqueType 86 unsigned UID; // The unique ID number for this class 87 88 /// RefCount - This counts the number of PATypeHolders that are pointing to 89 /// this type. When this number falls to zero, if the type is abstract and 90 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 91 /// derived types. 92 /// 93 mutable unsigned RefCount; 94 95 const Type *getForwardedTypeInternal() const; 96protected: 97 Type(const std::string& Name, TypeID id); 98 virtual ~Type() {} 99 100 101 /// Types can become nonabstract later, if they are refined. 102 /// 103 inline void setAbstract(bool Val) { Abstract = Val; } 104 105 /// isTypeAbstract - This method is used to calculate the Abstract bit. 106 /// 107 bool isTypeAbstract(); 108 109 unsigned getRefCount() const { return RefCount; } 110 111 /// ForwardType - This field is used to implement the union find scheme for 112 /// abstract types. When types are refined to other types, this field is set 113 /// to the more refined type. Only abstract types can be forwarded. 114 mutable const Type *ForwardType; 115 116 /// ContainedTys - The list of types contained by this one. For example, this 117 /// includes the arguments of a function type, the elements of the structure, 118 /// the pointee of a pointer, etc. Note that keeping this vector in the Type 119 /// class wastes some space for types that do not contain anything (such as 120 /// primitive types). However, keeping it here allows the subtype_* members 121 /// to be implemented MUCH more efficiently, and dynamically very few types do 122 /// not contain any elements (most are derived). 123 std::vector<PATypeHandle> ContainedTys; 124 125public: 126 virtual void print(std::ostream &O) const; 127 128 /// @brief Debugging support: print to stderr 129 virtual void dump() const; 130 131 /// setName - Associate the name with this type in the symbol table, but don't 132 /// set the local name to be equal specified name. 133 /// 134 virtual void setName(const std::string &Name, SymbolTable *ST = 0); 135 136 //===--------------------------------------------------------------------===// 137 // Property accessors for dealing with types... Some of these virtual methods 138 // are defined in private classes defined in Type.cpp for primitive types. 139 // 140 141 /// getTypeID - Return the type id for the type. This will return one 142 /// of the TypeID enum elements defined above. 143 /// 144 inline TypeID getTypeID() const { return ID; } 145 146 /// getUniqueID - Returns the UID of the type. This can be thought of as a 147 /// small integer version of the pointer to the type class. Two types that 148 /// are structurally different have different UIDs. This can be used for 149 /// indexing types into an array. 150 /// 151 inline unsigned getUniqueID() const { return UID; } 152 153 /// getDescription - Return the string representation of the type... 154 const std::string &getDescription() const; 155 156 /// isSigned - Return whether an integral numeric type is signed. This is 157 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for 158 /// Float and Double. 159 /// 160 bool isSigned() const { 161 return ID == SByteTyID || ID == ShortTyID || 162 ID == IntTyID || ID == LongTyID; 163 } 164 165 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite 166 /// the complement of isSigned... nonnumeric types return false as they do 167 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and 168 /// ULongTy 169 /// 170 bool isUnsigned() const { 171 return ID == UByteTyID || ID == UShortTyID || 172 ID == UIntTyID || ID == ULongTyID; 173 } 174 175 /// isInteger - Equilivant to isSigned() || isUnsigned() 176 /// 177 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; } 178 179 /// isIntegral - Returns true if this is an integral type, which is either 180 /// BoolTy or one of the Integer types. 181 /// 182 bool isIntegral() const { return isInteger() || this == BoolTy; } 183 184 /// isFloatingPoint - Return true if this is one of the two floating point 185 /// types 186 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; } 187 188 /// isAbstract - True if the type is either an Opaque type, or is a derived 189 /// type that includes an opaque type somewhere in it. 190 /// 191 inline bool isAbstract() const { return Abstract; } 192 193 /// isLosslesslyConvertibleTo - Return true if this type can be converted to 194 /// 'Ty' without any reinterpretation of bits. For example, uint to int. 195 /// 196 bool isLosslesslyConvertibleTo(const Type *Ty) const; 197 198 199 /// Here are some useful little methods to query what type derived types are 200 /// Note that all other types can just compare to see if this == Type::xxxTy; 201 /// 202 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 203 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 204 205 /// isFirstClassType - Return true if the value is holdable in a register. 206 inline bool isFirstClassType() const { 207 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || ID == PointerTyID; 208 } 209 210 /// isSized - Return true if it makes sense to take the size of this type. To 211 /// get the actual size for a particular target, it is reasonable to use the 212 /// TargetData subsystem to do this. 213 /// 214 bool isSized() const { 215 return (ID >= BoolTyID && ID <= DoubleTyID) || ID == PointerTyID || 216 isSizedDerivedType(); 217 } 218 219 /// getPrimitiveSize - Return the basic size of this type if it is a primative 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 getPrimitiveSize() const; 224 225 /// getUnsignedVersion - If this is an integer type, return the unsigned 226 /// variant of this type. For example int -> uint. 227 const Type *getUnsignedVersion() const; 228 229 /// getSignedVersion - If this is an integer type, return the signed variant 230 /// of this type. For example uint -> int. 231 const Type *getSignedVersion() const; 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 //===--------------------------------------------------------------------===// 243 // Type Iteration support 244 // 245 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator; 246 subtype_iterator subtype_begin() const { return ContainedTys.begin(); } 247 subtype_iterator subtype_end() const { return ContainedTys.end(); } 248 249 /// getContainedType - This method is used to implement the type iterator 250 /// (defined a the end of the file). For derived types, this returns the 251 /// types 'contained' in the derived type. 252 /// 253 const Type *getContainedType(unsigned i) const { 254 assert(i < ContainedTys.size() && "Index out of range!"); 255 return ContainedTys[i]; 256 } 257 258 /// getNumContainedTypes - Return the number of types in the derived type. 259 /// 260 unsigned getNumContainedTypes() const { return ContainedTys.size(); } 261 262 //===--------------------------------------------------------------------===// 263 // Static members exported by the Type class itself. Useful for getting 264 // instances of Type. 265 // 266 267 /// getPrimitiveType/getUniqueIDType - Return a type based on an identifier. 268 static const Type *getPrimitiveType(TypeID IDNumber); 269 static const Type *getUniqueIDType(unsigned UID); 270 271 //===--------------------------------------------------------------------===// 272 // These are the builtin types that are always available... 273 // 274 static Type *VoidTy , *BoolTy; 275 static Type *SByteTy, *UByteTy, 276 *ShortTy, *UShortTy, 277 *IntTy , *UIntTy, 278 *LongTy , *ULongTy; 279 static Type *FloatTy, *DoubleTy; 280 281 static Type* LabelTy; 282 283 /// Methods for support type inquiry through isa, cast, and dyn_cast: 284 static inline bool classof(const Type *T) { return true; } 285 286#include "llvm/Type.def" 287 288 // Virtual methods used by callbacks below. These should only be implemented 289 // in the DerivedType class. 290 virtual void addAbstractTypeUser(AbstractTypeUser *U) const { 291 abort(); // Only on derived types! 292 } 293 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const { 294 abort(); // Only on derived types! 295 } 296 297 void addRef() const { 298 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 299 ++RefCount; 300 } 301 302 void dropRef() const { 303 assert(isAbstract() && "Cannot drop a refernce to a non-abstract type!"); 304 assert(RefCount && "No objects are currently referencing this object!"); 305 306 // If this is the last PATypeHolder using this object, and there are no 307 // PATypeHandles using it, the type is dead, delete it now. 308 if (--RefCount == 0) 309 RefCountIsZero(); 310 } 311private: 312 /// isSizedDerivedType - Derived types like structures and arrays are sized 313 /// iff all of the members of the type are sized as well. Since asking for 314 /// their size is relatively uncommon, move this operation out of line. 315 bool isSizedDerivedType() const; 316 317 virtual void RefCountIsZero() const { 318 abort(); // only on derived types! 319 } 320 321}; 322 323//===----------------------------------------------------------------------===// 324// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 325// These are defined here because they MUST be inlined, yet are dependent on 326// the definition of the Type class. Of course Type derives from Value, which 327// contains an AbstractTypeUser instance, so there is no good way to factor out 328// the code. Hence this bit of uglyness. 329// 330// In the long term, Type should not derive from Value, allowing 331// AbstractTypeUser.h to #include Type.h, allowing us to eliminate this 332// nastyness entirely. 333// 334inline void PATypeHandle::addUser() { 335 assert(Ty && "Type Handle has a null type!"); 336 if (Ty->isAbstract()) 337 Ty->addAbstractTypeUser(User); 338} 339inline void PATypeHandle::removeUser() { 340 if (Ty->isAbstract()) 341 Ty->removeAbstractTypeUser(User); 342} 343 344inline void PATypeHandle::removeUserFromConcrete() { 345 if (!Ty->isAbstract()) 346 Ty->removeAbstractTypeUser(User); 347} 348 349// Define inline methods for PATypeHolder... 350 351inline void PATypeHolder::addRef() { 352 if (Ty->isAbstract()) 353 Ty->addRef(); 354} 355 356inline void PATypeHolder::dropRef() { 357 if (Ty->isAbstract()) 358 Ty->dropRef(); 359} 360 361/// get - This implements the forwarding part of the union-find algorithm for 362/// abstract types. Before every access to the Type*, we check to see if the 363/// type we are pointing to is forwarding to a new type. If so, we drop our 364/// reference to the type. 365/// 366inline const Type* PATypeHolder::get() const { 367 const Type *NewTy = Ty->getForwardedType(); 368 if (!NewTy) return Ty; 369 return *const_cast<PATypeHolder*>(this) = NewTy; 370} 371 372 373 374//===----------------------------------------------------------------------===// 375// Provide specializations of GraphTraits to be able to treat a type as a 376// graph of sub types... 377 378template <> struct GraphTraits<Type*> { 379 typedef Type NodeType; 380 typedef Type::subtype_iterator ChildIteratorType; 381 382 static inline NodeType *getEntryNode(Type *T) { return T; } 383 static inline ChildIteratorType child_begin(NodeType *N) { 384 return N->subtype_begin(); 385 } 386 static inline ChildIteratorType child_end(NodeType *N) { 387 return N->subtype_end(); 388 } 389}; 390 391template <> struct GraphTraits<const Type*> { 392 typedef const Type NodeType; 393 typedef Type::subtype_iterator ChildIteratorType; 394 395 static inline NodeType *getEntryNode(const Type *T) { return T; } 396 static inline ChildIteratorType child_begin(NodeType *N) { 397 return N->subtype_begin(); 398 } 399 static inline ChildIteratorType child_end(NodeType *N) { 400 return N->subtype_end(); 401 } 402}; 403 404template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 405 return Ty.getTypeID() == Type::PointerTyID; 406} 407 408std::ostream &operator<<(std::ostream &OS, const Type *T); 409std::ostream &operator<<(std::ostream &OS, const Type &T); 410 411} // End llvm namespace 412 413#endif 414