Type.h revision 2abbe867ab7a50e658712624b34c8957e9600674
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 weird 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 "llvm/Support/Casting.h" 39#include "llvm/ADT/GraphTraits.h" 40#include "llvm/ADT/iterator" 41#include <string> 42#include <vector> 43 44namespace llvm { 45 46class ArrayType; 47class DerivedType; 48class FunctionType; 49class OpaqueType; 50class PointerType; 51class StructType; 52class PackedType; 53class TypeMapBase; 54 55class Type : public AbstractTypeUser { 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 : 1; // 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 char *Name, TypeID id); 100 Type(TypeID id) : ID(id), Abstract(false), RefCount(0), ForwardType(0) {} 101 virtual ~Type() { 102 assert(AbstractTypeUsers.empty()); 103 } 104 105 /// Types can become nonabstract later, if they are refined. 106 /// 107 inline void setAbstract(bool Val) { Abstract = Val; } 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; 124 125 /// AbstractTypeUsers - Implement a list of the users that need to be notified 126 /// if I am a type, and I get resolved into a more concrete type. 127 /// 128 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 129public: 130 void print(std::ostream &O) const; 131 132 /// @brief Debugging support: print to stderr 133 void dump() const; 134 135 //===--------------------------------------------------------------------===// 136 // Property accessors for dealing with types... Some of these virtual methods 137 // are defined in private classes defined in Type.cpp for primitive types. 138 // 139 140 /// getTypeID - Return the type id for the type. This will return one 141 /// of the TypeID enum elements defined above. 142 /// 143 inline TypeID getTypeID() const { return ID; } 144 145 /// getDescription - Return the string representation of the type... 146 const std::string &getDescription() const; 147 148 /// isSigned - Return whether an integral numeric type is signed. This is 149 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for 150 /// Float and Double. 151 /// 152 bool isSigned() const { 153 return ID == SByteTyID || ID == ShortTyID || 154 ID == IntTyID || ID == LongTyID; 155 } 156 157 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite 158 /// the complement of isSigned... nonnumeric types return false as they do 159 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and 160 /// ULongTy 161 /// 162 bool isUnsigned() const { 163 return ID == UByteTyID || ID == UShortTyID || 164 ID == UIntTyID || ID == ULongTyID; 165 } 166 167 /// isInteger - Equivalent to isSigned() || isUnsigned() 168 /// 169 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; } 170 171 /// isIntegral - Returns true if this is an integral type, which is either 172 /// BoolTy or one of the Integer types. 173 /// 174 bool isIntegral() const { return isInteger() || this == BoolTy; } 175 176 /// isFloatingPoint - Return true if this is one of the two floating point 177 /// types 178 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; } 179 180 /// isAbstract - True if the type is either an Opaque type, or is a derived 181 /// type that includes an opaque type somewhere in it. 182 /// 183 inline bool isAbstract() const { return Abstract; } 184 185 /// isLosslesslyConvertibleTo - Return true if this type can be converted to 186 /// 'Ty' without any reinterpretation of bits. For example, uint to int. 187 /// 188 bool isLosslesslyConvertibleTo(const Type *Ty) const; 189 190 191 /// Here are some useful little methods to query what type derived types are 192 /// Note that all other types can just compare to see if this == Type::xxxTy; 193 /// 194 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 195 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 196 197 /// isFirstClassType - Return true if the value is holdable in a register. 198 /// 199 inline bool isFirstClassType() const { 200 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 201 ID == PointerTyID || ID == PackedTyID; 202 } 203 204 /// isSized - Return true if it makes sense to take the size of this type. To 205 /// get the actual size for a particular target, it is reasonable to use the 206 /// TargetData subsystem to do this. 207 /// 208 bool isSized() const { 209 // If it's a primitive, it is always sized. 210 if (ID >= BoolTyID && ID <= DoubleTyID || ID == PointerTyID) 211 return true; 212 // If it is not something that can have a size (e.g. a function or label), 213 // it doesn't have a size. 214 if (ID != StructTyID && ID != ArrayTyID && ID != PackedTyID) 215 return false; 216 // If it is something that can have a size and it's concrete, it definitely 217 // has a size, otherwise we have to try harder to decide. 218 return !isAbstract() || isSizedDerivedType(); 219 } 220 221 /// getPrimitiveSize - Return the basic size of this type if it is a primitive 222 /// type. These are fixed by LLVM and are not target dependent. This will 223 /// return zero if the type does not have a size or is not a primitive type. 224 /// 225 unsigned getPrimitiveSize() const; 226 unsigned getPrimitiveSizeInBits() const; 227 228 /// getUnsignedVersion - If this is an integer type, return the unsigned 229 /// variant of this type. For example int -> uint. 230 const Type *getUnsignedVersion() const; 231 232 /// getSignedVersion - If this is an integer type, return the signed variant 233 /// of this type. For example uint -> int. 234 const Type *getSignedVersion() const; 235 236 /// getForwaredType - Return the type that this type has been resolved to if 237 /// it has been resolved to anything. This is used to implement the 238 /// union-find algorithm for type resolution, and shouldn't be used by general 239 /// purpose clients. 240 const Type *getForwardedType() const { 241 if (!ForwardType) return 0; 242 return getForwardedTypeInternal(); 243 } 244 245 /// getVAArgsPromotedType - Return the type an argument of this type 246 /// will be promoted to if passed through a variable argument 247 /// function. 248 const Type *getVAArgsPromotedType() const { 249 if (ID == BoolTyID || ID == UByteTyID || ID == UShortTyID) 250 return Type::UIntTy; 251 else if (ID == SByteTyID || ID == ShortTyID) 252 return Type::IntTy; 253 else if (ID == FloatTyID) 254 return Type::DoubleTy; 255 else 256 return this; 257 } 258 259 //===--------------------------------------------------------------------===// 260 // Type Iteration support 261 // 262 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator; 263 subtype_iterator subtype_begin() const { return ContainedTys.begin(); } 264 subtype_iterator subtype_end() const { return ContainedTys.end(); } 265 266 /// getContainedType - This method is used to implement the type iterator 267 /// (defined a the end of the file). For derived types, this returns the 268 /// types 'contained' in the derived type. 269 /// 270 const Type *getContainedType(unsigned i) const { 271 assert(i < ContainedTys.size() && "Index out of range!"); 272 return ContainedTys[i]; 273 } 274 275 /// getNumContainedTypes - Return the number of types in the derived type. 276 /// 277 typedef std::vector<PATypeHandle>::size_type size_type; 278 size_type getNumContainedTypes() const { return ContainedTys.size(); } 279 280 //===--------------------------------------------------------------------===// 281 // Static members exported by the Type class itself. Useful for getting 282 // instances of Type. 283 // 284 285 /// getPrimitiveType - Return a type based on an identifier. 286 static const Type *getPrimitiveType(TypeID IDNumber); 287 288 //===--------------------------------------------------------------------===// 289 // These are the builtin types that are always available... 290 // 291 static Type *VoidTy , *BoolTy; 292 static Type *SByteTy, *UByteTy, 293 *ShortTy, *UShortTy, 294 *IntTy , *UIntTy, 295 *LongTy , *ULongTy; 296 static Type *FloatTy, *DoubleTy; 297 298 static Type* LabelTy; 299 300 /// Methods for support type inquiry through isa, cast, and dyn_cast: 301 static inline bool classof(const Type *T) { return true; } 302 303 void addRef() const { 304 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 305 ++RefCount; 306 } 307 308 void dropRef() const { 309 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 310 assert(RefCount && "No objects are currently referencing this object!"); 311 312 // If this is the last PATypeHolder using this object, and there are no 313 // PATypeHandles using it, the type is dead, delete it now. 314 if (--RefCount == 0 && AbstractTypeUsers.empty()) 315 delete this; 316 } 317 318 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 319 /// it. This function is called primarily by the PATypeHandle class. 320 /// 321 void addAbstractTypeUser(AbstractTypeUser *U) const { 322 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 323 AbstractTypeUsers.push_back(U); 324 } 325 326 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 327 /// no longer has a handle to the type. This function is called primarily by 328 /// the PATypeHandle class. When there are no users of the abstract type, it 329 /// is annihilated, because there is no way to get a reference to it ever 330 /// again. 331 /// 332 void removeAbstractTypeUser(AbstractTypeUser *U) const; 333 334 /// clearAllTypeMaps - This method frees all internal memory used by the 335 /// type subsystem, which can be used in environments where this memory is 336 /// otherwise reported as a leak. 337 static void clearAllTypeMaps(); 338 339private: 340 /// isSizedDerivedType - Derived types like structures and arrays are sized 341 /// iff all of the members of the type are sized as well. Since asking for 342 /// their size is relatively uncommon, move this operation out of line. 343 bool isSizedDerivedType() const; 344 345 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 346 virtual void typeBecameConcrete(const DerivedType *AbsTy); 347 348protected: 349 // PromoteAbstractToConcrete - This is an internal method used to calculate 350 // change "Abstract" from true to false when types are refined. 351 void PromoteAbstractToConcrete(); 352 friend class TypeMapBase; 353}; 354 355//===----------------------------------------------------------------------===// 356// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 357// These are defined here because they MUST be inlined, yet are dependent on 358// the definition of the Type class. Of course Type derives from Value, which 359// contains an AbstractTypeUser instance, so there is no good way to factor out 360// the code. Hence this bit of uglyness. 361// 362// In the long term, Type should not derive from Value, allowing 363// AbstractTypeUser.h to #include Type.h, allowing us to eliminate this 364// nastyness entirely. 365// 366inline void PATypeHandle::addUser() { 367 assert(Ty && "Type Handle has a null type!"); 368 if (Ty->isAbstract()) 369 Ty->addAbstractTypeUser(User); 370} 371inline void PATypeHandle::removeUser() { 372 if (Ty->isAbstract()) 373 Ty->removeAbstractTypeUser(User); 374} 375 376// Define inline methods for PATypeHolder... 377 378inline void PATypeHolder::addRef() { 379 if (Ty->isAbstract()) 380 Ty->addRef(); 381} 382 383inline void PATypeHolder::dropRef() { 384 if (Ty->isAbstract()) 385 Ty->dropRef(); 386} 387 388/// get - This implements the forwarding part of the union-find algorithm for 389/// abstract types. Before every access to the Type*, we check to see if the 390/// type we are pointing to is forwarding to a new type. If so, we drop our 391/// reference to the type. 392/// 393inline Type* PATypeHolder::get() const { 394 const Type *NewTy = Ty->getForwardedType(); 395 if (!NewTy) return const_cast<Type*>(Ty); 396 return *const_cast<PATypeHolder*>(this) = NewTy; 397} 398 399 400 401//===----------------------------------------------------------------------===// 402// Provide specializations of GraphTraits to be able to treat a type as a 403// graph of sub types... 404 405template <> struct GraphTraits<Type*> { 406 typedef Type NodeType; 407 typedef Type::subtype_iterator ChildIteratorType; 408 409 static inline NodeType *getEntryNode(Type *T) { return T; } 410 static inline ChildIteratorType child_begin(NodeType *N) { 411 return N->subtype_begin(); 412 } 413 static inline ChildIteratorType child_end(NodeType *N) { 414 return N->subtype_end(); 415 } 416}; 417 418template <> struct GraphTraits<const Type*> { 419 typedef const Type NodeType; 420 typedef Type::subtype_iterator ChildIteratorType; 421 422 static inline NodeType *getEntryNode(const Type *T) { return T; } 423 static inline ChildIteratorType child_begin(NodeType *N) { 424 return N->subtype_begin(); 425 } 426 static inline ChildIteratorType child_end(NodeType *N) { 427 return N->subtype_end(); 428 } 429}; 430 431template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 432 return Ty.getTypeID() == Type::PointerTyID; 433} 434 435std::ostream &operator<<(std::ostream &OS, const Type &T); 436 437} // End llvm namespace 438 439#endif 440