Type.h revision 207f2d4056ac6991419603179911cb09cf4a9966
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// Opaque types are considered to be first-class types. 33// 34//===----------------------------------------------------------------------===// 35 36#ifndef LLVM_TYPE_H 37#define LLVM_TYPE_H 38 39#include "AbstractTypeUser.h" 40#include "llvm/Support/Casting.h" 41#include "llvm/ADT/GraphTraits.h" 42#include "llvm/ADT/iterator" 43#include <vector> 44 45namespace llvm { 46 47class ArrayType; 48class DerivedType; 49class FunctionType; 50class OpaqueType; 51class PointerType; 52class StructType; 53class PackedType; 54 55class Type { 56public: 57 ///===-------------------------------------------------------------------===// 58 /// Definitions of all of the base types for the Type system. Based on this 59 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h) 60 /// Note: If you add an element to this, you need to add an element to the 61 /// Type::getPrimitiveType function, or else things will break! 62 /// 63 enum TypeID { 64 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date 65 VoidTyID = 0 , BoolTyID, // 0, 1: Basics... 66 UByteTyID , SByteTyID, // 2, 3: 8 bit types... 67 UShortTyID , ShortTyID, // 4, 5: 16 bit types... 68 UIntTyID , IntTyID, // 6, 7: 32 bit types... 69 ULongTyID , LongTyID, // 8, 9: 64 bit types... 70 FloatTyID , DoubleTyID, // 10,11: Floating point types... 71 LabelTyID , // 12 : Labels... 72 73 // Derived types... see DerivedTypes.h file... 74 // Make sure FirstDerivedTyID stays up to date!!! 75 FunctionTyID , StructTyID, // Functions... Structs... 76 ArrayTyID , PointerTyID, // Array... pointer... 77 OpaqueTyID, // Opaque type instances... 78 PackedTyID, // SIMD 'packed' format... 79 //... 80 81 NumTypeIDs, // Must remain as last defined ID 82 LastPrimitiveTyID = LabelTyID, 83 FirstDerivedTyID = FunctionTyID, 84 }; 85 86private: 87 TypeID ID : 8; // The current base type of this type. 88 bool Abstract; // True if type contains an OpaqueType 89 90 /// RefCount - This counts the number of PATypeHolders that are pointing to 91 /// this type. When this number falls to zero, if the type is abstract and 92 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 93 /// derived types. 94 /// 95 mutable unsigned RefCount; 96 97 const Type *getForwardedTypeInternal() const; 98protected: 99 Type(const std::string& Name, TypeID id); 100 virtual ~Type() {} 101 102 /// Types can become nonabstract later, if they are refined. 103 /// 104 inline void setAbstract(bool Val) { Abstract = Val; } 105 106 // PromoteAbstractToConcrete - This is an internal method used to calculate 107 // change "Abstract" from true to false when types are refined. 108 void PromoteAbstractToConcrete(); 109 110 unsigned getRefCount() const { return RefCount; } 111 112 /// ForwardType - This field is used to implement the union find scheme for 113 /// abstract types. When types are refined to other types, this field is set 114 /// to the more refined type. Only abstract types can be forwarded. 115 mutable const Type *ForwardType; 116 117 /// ContainedTys - The list of types contained by this one. For example, this 118 /// includes the arguments of a function type, the elements of the structure, 119 /// the pointee of a pointer, etc. Note that keeping this vector in the Type 120 /// class wastes some space for types that do not contain anything (such as 121 /// primitive types). However, keeping it here allows the subtype_* members 122 /// to be implemented MUCH more efficiently, and dynamically very few types do 123 /// not contain any elements (most are derived). 124 std::vector<PATypeHandle> ContainedTys; 125 126public: 127 virtual void print(std::ostream &O) const; 128 129 /// @brief Debugging support: print to stderr 130 virtual void dump() const; 131 132 //===--------------------------------------------------------------------===// 133 // Property accessors for dealing with types... Some of these virtual methods 134 // are defined in private classes defined in Type.cpp for primitive types. 135 // 136 137 /// getTypeID - Return the type id for the type. This will return one 138 /// of the TypeID enum elements defined above. 139 /// 140 inline TypeID getTypeID() const { return ID; } 141 142 /// getDescription - Return the string representation of the type... 143 const std::string &getDescription() const; 144 145 /// isSigned - Return whether an integral numeric type is signed. This is 146 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for 147 /// Float and Double. 148 /// 149 bool isSigned() const { 150 return ID == SByteTyID || ID == ShortTyID || 151 ID == IntTyID || ID == LongTyID; 152 } 153 154 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite 155 /// the complement of isSigned... nonnumeric types return false as they do 156 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and 157 /// ULongTy 158 /// 159 bool isUnsigned() const { 160 return ID == UByteTyID || ID == UShortTyID || 161 ID == UIntTyID || ID == ULongTyID; 162 } 163 164 /// isInteger - Equivalent to isSigned() || isUnsigned() 165 /// 166 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; } 167 168 /// isIntegral - Returns true if this is an integral type, which is either 169 /// BoolTy or one of the Integer types. 170 /// 171 bool isIntegral() const { return isInteger() || this == BoolTy; } 172 173 /// isFloatingPoint - Return true if this is one of the two floating point 174 /// types 175 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; } 176 177 /// isAbstract - True if the type is either an Opaque type, or is a derived 178 /// type that includes an opaque type somewhere in it. 179 /// 180 inline bool isAbstract() const { return Abstract; } 181 182 /// isLosslesslyConvertibleTo - Return true if this type can be converted to 183 /// 'Ty' without any reinterpretation of bits. For example, uint to int. 184 /// 185 bool isLosslesslyConvertibleTo(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 inline bool isFirstClassType() const { 196 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 197 ID == PointerTyID || ID == PackedTyID || ID == OpaqueTyID; 198 } 199 200 /// isSized - Return true if it makes sense to take the size of this type. To 201 /// get the actual size for a particular target, it is reasonable to use the 202 /// TargetData subsystem to do this. 203 /// 204 bool isSized() const { 205 return (ID >= BoolTyID && ID <= DoubleTyID) || ID == PointerTyID || 206 isSizedDerivedType(); 207 } 208 209 /// getPrimitiveSize - Return the basic size of this type if it is a primitive 210 /// type. These are fixed by LLVM and are not target dependent. This will 211 /// return zero if the type does not have a size or is not a primitive type. 212 /// 213 unsigned getPrimitiveSize() const; 214 215 /// getUnsignedVersion - If this is an integer type, return the unsigned 216 /// variant of this type. For example int -> uint. 217 const Type *getUnsignedVersion() const; 218 219 /// getSignedVersion - If this is an integer type, return the signed variant 220 /// of this type. For example uint -> int. 221 const Type *getSignedVersion() const; 222 223 /// getForwaredType - Return the type that this type has been resolved to if 224 /// it has been resolved to anything. This is used to implement the 225 /// union-find algorithm for type resolution, and shouldn't be used by general 226 /// purpose clients. 227 const Type *getForwardedType() const { 228 if (!ForwardType) return 0; 229 return getForwardedTypeInternal(); 230 } 231 232 //===--------------------------------------------------------------------===// 233 // Type Iteration support 234 // 235 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator; 236 subtype_iterator subtype_begin() const { return ContainedTys.begin(); } 237 subtype_iterator subtype_end() const { return ContainedTys.end(); } 238 239 /// getContainedType - This method is used to implement the type iterator 240 /// (defined a the end of the file). For derived types, this returns the 241 /// types 'contained' in the derived type. 242 /// 243 const Type *getContainedType(unsigned i) const { 244 assert(i < ContainedTys.size() && "Index out of range!"); 245 return ContainedTys[i]; 246 } 247 248 /// getNumContainedTypes - Return the number of types in the derived type. 249 /// 250 unsigned getNumContainedTypes() const { return ContainedTys.size(); } 251 252 //===--------------------------------------------------------------------===// 253 // Static members exported by the Type class itself. Useful for getting 254 // instances of Type. 255 // 256 257 /// getPrimitiveType - Return a type based on an identifier. 258 static const Type *getPrimitiveType(TypeID IDNumber); 259 260 //===--------------------------------------------------------------------===// 261 // These are the builtin types that are always available... 262 // 263 static Type *VoidTy , *BoolTy; 264 static Type *SByteTy, *UByteTy, 265 *ShortTy, *UShortTy, 266 *IntTy , *UIntTy, 267 *LongTy , *ULongTy; 268 static Type *FloatTy, *DoubleTy; 269 270 static Type* LabelTy; 271 272 /// Methods for support type inquiry through isa, cast, and dyn_cast: 273 static inline bool classof(const Type *T) { return true; } 274 275#include "llvm/Type.def" 276 277 // Virtual methods used by callbacks below. These should only be implemented 278 // in the DerivedType class. 279 virtual void addAbstractTypeUser(AbstractTypeUser *U) const { 280 abort(); // Only on derived types! 281 } 282 virtual void removeAbstractTypeUser(AbstractTypeUser *U) const { 283 abort(); // Only on derived types! 284 } 285 286 void addRef() const { 287 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 288 ++RefCount; 289 } 290 291 void dropRef() const { 292 assert(isAbstract() && "Cannot drop a refernce to a non-abstract type!"); 293 assert(RefCount && "No objects are currently referencing this object!"); 294 295 // If this is the last PATypeHolder using this object, and there are no 296 // PATypeHandles using it, the type is dead, delete it now. 297 if (--RefCount == 0) 298 RefCountIsZero(); 299 } 300private: 301 /// isSizedDerivedType - Derived types like structures and arrays are sized 302 /// iff all of the members of the type are sized as well. Since asking for 303 /// their size is relatively uncommon, move this operation out of line. 304 bool isSizedDerivedType() const; 305 306 virtual void RefCountIsZero() const { 307 abort(); // only on derived types! 308 } 309 310}; 311 312//===----------------------------------------------------------------------===// 313// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 314// These are defined here because they MUST be inlined, yet are dependent on 315// the definition of the Type class. Of course Type derives from Value, which 316// contains an AbstractTypeUser instance, so there is no good way to factor out 317// the code. Hence this bit of uglyness. 318// 319// In the long term, Type should not derive from Value, allowing 320// AbstractTypeUser.h to #include Type.h, allowing us to eliminate this 321// nastyness entirely. 322// 323inline void PATypeHandle::addUser() { 324 assert(Ty && "Type Handle has a null type!"); 325 if (Ty->isAbstract()) 326 Ty->addAbstractTypeUser(User); 327} 328inline void PATypeHandle::removeUser() { 329 if (Ty->isAbstract()) 330 Ty->removeAbstractTypeUser(User); 331} 332 333inline void PATypeHandle::removeUserFromConcrete() { 334 if (!Ty->isAbstract()) 335 Ty->removeAbstractTypeUser(User); 336} 337 338// Define inline methods for PATypeHolder... 339 340inline void PATypeHolder::addRef() { 341 if (Ty->isAbstract()) 342 Ty->addRef(); 343} 344 345inline void PATypeHolder::dropRef() { 346 if (Ty->isAbstract()) 347 Ty->dropRef(); 348} 349 350/// get - This implements the forwarding part of the union-find algorithm for 351/// abstract types. Before every access to the Type*, we check to see if the 352/// type we are pointing to is forwarding to a new type. If so, we drop our 353/// reference to the type. 354/// 355inline Type* PATypeHolder::get() const { 356 const Type *NewTy = Ty->getForwardedType(); 357 if (!NewTy) return const_cast<Type*>(Ty); 358 return *const_cast<PATypeHolder*>(this) = NewTy; 359} 360 361 362 363//===----------------------------------------------------------------------===// 364// Provide specializations of GraphTraits to be able to treat a type as a 365// graph of sub types... 366 367template <> struct GraphTraits<Type*> { 368 typedef Type NodeType; 369 typedef Type::subtype_iterator ChildIteratorType; 370 371 static inline NodeType *getEntryNode(Type *T) { return T; } 372 static inline ChildIteratorType child_begin(NodeType *N) { 373 return N->subtype_begin(); 374 } 375 static inline ChildIteratorType child_end(NodeType *N) { 376 return N->subtype_end(); 377 } 378}; 379 380template <> struct GraphTraits<const Type*> { 381 typedef const Type NodeType; 382 typedef Type::subtype_iterator ChildIteratorType; 383 384 static inline NodeType *getEntryNode(const Type *T) { return T; } 385 static inline ChildIteratorType child_begin(NodeType *N) { 386 return N->subtype_begin(); 387 } 388 static inline ChildIteratorType child_end(NodeType *N) { 389 return N->subtype_end(); 390 } 391}; 392 393template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 394 return Ty.getTypeID() == Type::PointerTyID; 395} 396 397std::ostream &operator<<(std::ostream &OS, const Type &T); 398 399} // End llvm namespace 400 401#endif 402