LLVM API Documentation
00001 //===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License. See LICENSE.TXT for details. 00007 // 00008 //===----------------------------------------------------------------------===// 00009 00010 00011 #ifndef LLVM_TYPE_H 00012 #define LLVM_TYPE_H 00013 00014 #include "llvm/AbstractTypeUser.h" 00015 #include "llvm/Support/Casting.h" 00016 #include "llvm/Support/DataTypes.h" 00017 #include "llvm/ADT/GraphTraits.h" 00018 #include "llvm/ADT/iterator" 00019 #include <string> 00020 #include <vector> 00021 00022 namespace llvm { 00023 00024 class ArrayType; 00025 class DerivedType; 00026 class FunctionType; 00027 class OpaqueType; 00028 class PointerType; 00029 class StructType; 00030 class PackedType; 00031 class TypeMapBase; 00032 00033 /// This file contains the declaration of the Type class. For more "Type" type 00034 /// stuff, look in DerivedTypes.h. 00035 /// 00036 /// The instances of the Type class are immutable: once they are created, 00037 /// they are never changed. Also note that only one instance of a particular 00038 /// type is ever created. Thus seeing if two types are equal is a matter of 00039 /// doing a trivial pointer comparison. To enforce that no two equal instances 00040 /// are created, Type instances can only be created via static factory methods 00041 /// in class Type and in derived classes. 00042 /// 00043 /// Once allocated, Types are never free'd, unless they are an abstract type 00044 /// that is resolved to a more concrete type. 00045 /// 00046 /// Types themself don't have a name, and can be named either by: 00047 /// - using SymbolTable instance, typically from some Module, 00048 /// - using convenience methods in the Module class (which uses module's 00049 /// SymbolTable too). 00050 /// 00051 /// Opaque types are simple derived types with no state. There may be many 00052 /// different Opaque type objects floating around, but two are only considered 00053 /// identical if they are pointer equals of each other. This allows us to have 00054 /// two opaque types that end up resolving to different concrete types later. 00055 /// 00056 /// Opaque types are also kinda weird and scary and different because they have 00057 /// to keep a list of uses of the type. When, through linking, parsing, or 00058 /// bytecode reading, they become resolved, they need to find and update all 00059 /// users of the unknown type, causing them to reference a new, more concrete 00060 /// type. Opaque types are deleted when their use list dwindles to zero users. 00061 /// 00062 /// @brief Root of type hierarchy 00063 class Type : public AbstractTypeUser { 00064 public: 00065 ///===-------------------------------------------------------------------===// 00066 /// Definitions of all of the base types for the Type system. Based on this 00067 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h) 00068 /// Note: If you add an element to this, you need to add an element to the 00069 /// Type::getPrimitiveType function, or else things will break! 00070 /// 00071 enum TypeID { 00072 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date 00073 VoidTyID = 0 , BoolTyID, // 0, 1: Basics... 00074 UByteTyID , SByteTyID, // 2, 3: 8 bit types... 00075 UShortTyID , ShortTyID, // 4, 5: 16 bit types... 00076 UIntTyID , IntTyID, // 6, 7: 32 bit types... 00077 ULongTyID , LongTyID, // 8, 9: 64 bit types... 00078 FloatTyID , DoubleTyID, // 10,11: Floating point types... 00079 LabelTyID , // 12 : Labels... 00080 00081 // Derived types... see DerivedTypes.h file... 00082 // Make sure FirstDerivedTyID stays up to date!!! 00083 FunctionTyID , StructTyID, // Functions... Structs... 00084 ArrayTyID , PointerTyID, // Array... pointer... 00085 OpaqueTyID, // Opaque type instances... 00086 PackedTyID, // SIMD 'packed' format... 00087 //... 00088 00089 NumTypeIDs, // Must remain as last defined ID 00090 LastPrimitiveTyID = LabelTyID, 00091 FirstDerivedTyID = FunctionTyID 00092 }; 00093 00094 private: 00095 TypeID ID : 8; // The current base type of this type. 00096 bool Abstract : 1; // True if type contains an OpaqueType 00097 00098 /// RefCount - This counts the number of PATypeHolders that are pointing to 00099 /// this type. When this number falls to zero, if the type is abstract and 00100 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for 00101 /// derived types. 00102 /// 00103 mutable unsigned RefCount; 00104 00105 const Type *getForwardedTypeInternal() const; 00106 protected: 00107 Type(const char *Name, TypeID id); 00108 Type(TypeID id) : ID(id), Abstract(false), RefCount(0), ForwardType(0) {} 00109 virtual ~Type() { 00110 assert(AbstractTypeUsers.empty()); 00111 } 00112 00113 /// Types can become nonabstract later, if they are refined. 00114 /// 00115 inline void setAbstract(bool Val) { Abstract = Val; } 00116 00117 unsigned getRefCount() const { return RefCount; } 00118 00119 /// ForwardType - This field is used to implement the union find scheme for 00120 /// abstract types. When types are refined to other types, this field is set 00121 /// to the more refined type. Only abstract types can be forwarded. 00122 mutable const Type *ForwardType; 00123 00124 /// ContainedTys - The list of types contained by this one. For example, this 00125 /// includes the arguments of a function type, the elements of the structure, 00126 /// the pointee of a pointer, etc. Note that keeping this vector in the Type 00127 /// class wastes some space for types that do not contain anything (such as 00128 /// primitive types). However, keeping it here allows the subtype_* members 00129 /// to be implemented MUCH more efficiently, and dynamically very few types do 00130 /// not contain any elements (most are derived). 00131 std::vector<PATypeHandle> ContainedTys; 00132 00133 /// AbstractTypeUsers - Implement a list of the users that need to be notified 00134 /// if I am a type, and I get resolved into a more concrete type. 00135 /// 00136 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers; 00137 public: 00138 void print(std::ostream &O) const; 00139 00140 /// @brief Debugging support: print to stderr 00141 void dump() const; 00142 00143 //===--------------------------------------------------------------------===// 00144 // Property accessors for dealing with types... Some of these virtual methods 00145 // are defined in private classes defined in Type.cpp for primitive types. 00146 // 00147 00148 /// getTypeID - Return the type id for the type. This will return one 00149 /// of the TypeID enum elements defined above. 00150 /// 00151 inline TypeID getTypeID() const { return ID; } 00152 00153 /// getDescription - Return the string representation of the type... 00154 const std::string &getDescription() const; 00155 00156 /// isSigned - Return whether an integral numeric type is signed. This is 00157 /// true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for 00158 /// Float and Double. 00159 /// 00160 bool isSigned() const { 00161 return ID == SByteTyID || ID == ShortTyID || 00162 ID == IntTyID || ID == LongTyID; 00163 } 00164 00165 /// isUnsigned - Return whether a numeric type is unsigned. This is not quite 00166 /// the complement of isSigned... nonnumeric types return false as they do 00167 /// with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and 00168 /// ULongTy 00169 /// 00170 bool isUnsigned() const { 00171 return ID == UByteTyID || ID == UShortTyID || 00172 ID == UIntTyID || ID == ULongTyID; 00173 } 00174 00175 /// isInteger - Equivalent to isSigned() || isUnsigned() 00176 /// 00177 bool isInteger() const { return ID >= UByteTyID && ID <= LongTyID; } 00178 00179 /// isIntegral - Returns true if this is an integral type, which is either 00180 /// BoolTy or one of the Integer types. 00181 /// 00182 bool isIntegral() const { return isInteger() || this == BoolTy; } 00183 00184 /// isFloatingPoint - Return true if this is one of the two floating point 00185 /// types 00186 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID; } 00187 00188 /// isAbstract - True if the type is either an Opaque type, or is a derived 00189 /// type that includes an opaque type somewhere in it. 00190 /// 00191 inline bool isAbstract() const { return Abstract; } 00192 00193 /// isLosslesslyConvertibleTo - Return true if this type can be converted to 00194 /// 'Ty' without any reinterpretation of bits. For example, uint to int. 00195 /// 00196 bool isLosslesslyConvertibleTo(const Type *Ty) const; 00197 00198 00199 /// Here are some useful little methods to query what type derived types are 00200 /// Note that all other types can just compare to see if this == Type::xxxTy; 00201 /// 00202 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; } 00203 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; } 00204 00205 /// isFirstClassType - Return true if the value is holdable in a register. 00206 /// 00207 inline bool isFirstClassType() const { 00208 return (ID != VoidTyID && ID <= LastPrimitiveTyID) || 00209 ID == PointerTyID || ID == PackedTyID; 00210 } 00211 00212 /// isSized - Return true if it makes sense to take the size of this type. To 00213 /// get the actual size for a particular target, it is reasonable to use the 00214 /// TargetData subsystem to do this. 00215 /// 00216 bool isSized() const { 00217 // If it's a primitive, it is always sized. 00218 if (ID >= BoolTyID && ID <= DoubleTyID || ID == PointerTyID) 00219 return true; 00220 // If it is not something that can have a size (e.g. a function or label), 00221 // it doesn't have a size. 00222 if (ID != StructTyID && ID != ArrayTyID && ID != PackedTyID) 00223 return false; 00224 // If it is something that can have a size and it's concrete, it definitely 00225 // has a size, otherwise we have to try harder to decide. 00226 return !isAbstract() || isSizedDerivedType(); 00227 } 00228 00229 /// getPrimitiveSize - Return the basic size of this type if it is a primitive 00230 /// type. These are fixed by LLVM and are not target dependent. This will 00231 /// return zero if the type does not have a size or is not a primitive type. 00232 /// 00233 unsigned getPrimitiveSize() const; 00234 unsigned getPrimitiveSizeInBits() const; 00235 00236 /// getUnsignedVersion - If this is an integer type, return the unsigned 00237 /// variant of this type. For example int -> uint. 00238 const Type *getUnsignedVersion() const; 00239 00240 /// getSignedVersion - If this is an integer type, return the signed variant 00241 /// of this type. For example uint -> int. 00242 const Type *getSignedVersion() const; 00243 00244 /// getIntegralTypeMask - Return a bitmask with ones set for all of the bits 00245 /// that can be set by an unsigned version of this type. This is 0xFF for 00246 /// sbyte/ubyte, 0xFFFF for shorts, etc. 00247 uint64_t getIntegralTypeMask() const { 00248 assert(isIntegral() && "This only works for integral types!"); 00249 return ~uint64_t(0UL) >> (64-getPrimitiveSizeInBits()); 00250 } 00251 00252 /// getForwaredType - Return the type that this type has been resolved to if 00253 /// it has been resolved to anything. This is used to implement the 00254 /// union-find algorithm for type resolution, and shouldn't be used by general 00255 /// purpose clients. 00256 const Type *getForwardedType() const { 00257 if (!ForwardType) return 0; 00258 return getForwardedTypeInternal(); 00259 } 00260 00261 /// getVAArgsPromotedType - Return the type an argument of this type 00262 /// will be promoted to if passed through a variable argument 00263 /// function. 00264 const Type *getVAArgsPromotedType() const { 00265 if (ID == BoolTyID || ID == UByteTyID || ID == UShortTyID) 00266 return Type::UIntTy; 00267 else if (ID == SByteTyID || ID == ShortTyID) 00268 return Type::IntTy; 00269 else if (ID == FloatTyID) 00270 return Type::DoubleTy; 00271 else 00272 return this; 00273 } 00274 00275 //===--------------------------------------------------------------------===// 00276 // Type Iteration support 00277 // 00278 typedef std::vector<PATypeHandle>::const_iterator subtype_iterator; 00279 subtype_iterator subtype_begin() const { return ContainedTys.begin(); } 00280 subtype_iterator subtype_end() const { return ContainedTys.end(); } 00281 00282 /// getContainedType - This method is used to implement the type iterator 00283 /// (defined a the end of the file). For derived types, this returns the 00284 /// types 'contained' in the derived type. 00285 /// 00286 const Type *getContainedType(unsigned i) const { 00287 assert(i < ContainedTys.size() && "Index out of range!"); 00288 return ContainedTys[i]; 00289 } 00290 00291 /// getNumContainedTypes - Return the number of types in the derived type. 00292 /// 00293 typedef std::vector<PATypeHandle>::size_type size_type; 00294 size_type getNumContainedTypes() const { return ContainedTys.size(); } 00295 00296 //===--------------------------------------------------------------------===// 00297 // Static members exported by the Type class itself. Useful for getting 00298 // instances of Type. 00299 // 00300 00301 /// getPrimitiveType - Return a type based on an identifier. 00302 static const Type *getPrimitiveType(TypeID IDNumber); 00303 00304 //===--------------------------------------------------------------------===// 00305 // These are the builtin types that are always available... 00306 // 00307 static Type *VoidTy , *BoolTy; 00308 static Type *SByteTy, *UByteTy, 00309 *ShortTy, *UShortTy, 00310 *IntTy , *UIntTy, 00311 *LongTy , *ULongTy; 00312 static Type *FloatTy, *DoubleTy; 00313 00314 static Type* LabelTy; 00315 00316 /// Methods for support type inquiry through isa, cast, and dyn_cast: 00317 static inline bool classof(const Type *T) { return true; } 00318 00319 void addRef() const { 00320 assert(isAbstract() && "Cannot add a reference to a non-abstract type!"); 00321 ++RefCount; 00322 } 00323 00324 void dropRef() const { 00325 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!"); 00326 assert(RefCount && "No objects are currently referencing this object!"); 00327 00328 // If this is the last PATypeHolder using this object, and there are no 00329 // PATypeHandles using it, the type is dead, delete it now. 00330 if (--RefCount == 0 && AbstractTypeUsers.empty()) 00331 delete this; 00332 } 00333 00334 /// addAbstractTypeUser - Notify an abstract type that there is a new user of 00335 /// it. This function is called primarily by the PATypeHandle class. 00336 /// 00337 void addAbstractTypeUser(AbstractTypeUser *U) const { 00338 assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!"); 00339 AbstractTypeUsers.push_back(U); 00340 } 00341 00342 /// removeAbstractTypeUser - Notify an abstract type that a user of the class 00343 /// no longer has a handle to the type. This function is called primarily by 00344 /// the PATypeHandle class. When there are no users of the abstract type, it 00345 /// is annihilated, because there is no way to get a reference to it ever 00346 /// again. 00347 /// 00348 void removeAbstractTypeUser(AbstractTypeUser *U) const; 00349 00350 /// clearAllTypeMaps - This method frees all internal memory used by the 00351 /// type subsystem, which can be used in environments where this memory is 00352 /// otherwise reported as a leak. 00353 static void clearAllTypeMaps(); 00354 00355 private: 00356 /// isSizedDerivedType - Derived types like structures and arrays are sized 00357 /// iff all of the members of the type are sized as well. Since asking for 00358 /// their size is relatively uncommon, move this operation out of line. 00359 bool isSizedDerivedType() const; 00360 00361 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy); 00362 virtual void typeBecameConcrete(const DerivedType *AbsTy); 00363 00364 protected: 00365 // PromoteAbstractToConcrete - This is an internal method used to calculate 00366 // change "Abstract" from true to false when types are refined. 00367 void PromoteAbstractToConcrete(); 00368 friend class TypeMapBase; 00369 }; 00370 00371 //===----------------------------------------------------------------------===// 00372 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class. 00373 // These are defined here because they MUST be inlined, yet are dependent on 00374 // the definition of the Type class. Of course Type derives from Value, which 00375 // contains an AbstractTypeUser instance, so there is no good way to factor out 00376 // the code. Hence this bit of uglyness. 00377 // 00378 // In the long term, Type should not derive from Value, allowing 00379 // AbstractTypeUser.h to #include Type.h, allowing us to eliminate this 00380 // nastyness entirely. 00381 // 00382 inline void PATypeHandle::addUser() { 00383 assert(Ty && "Type Handle has a null type!"); 00384 if (Ty->isAbstract()) 00385 Ty->addAbstractTypeUser(User); 00386 } 00387 inline void PATypeHandle::removeUser() { 00388 if (Ty->isAbstract()) 00389 Ty->removeAbstractTypeUser(User); 00390 } 00391 00392 // Define inline methods for PATypeHolder... 00393 00394 inline void PATypeHolder::addRef() { 00395 if (Ty->isAbstract()) 00396 Ty->addRef(); 00397 } 00398 00399 inline void PATypeHolder::dropRef() { 00400 if (Ty->isAbstract()) 00401 Ty->dropRef(); 00402 } 00403 00404 00405 //===----------------------------------------------------------------------===// 00406 // Provide specializations of GraphTraits to be able to treat a type as a 00407 // graph of sub types... 00408 00409 template <> struct GraphTraits<Type*> { 00410 typedef Type NodeType; 00411 typedef Type::subtype_iterator ChildIteratorType; 00412 00413 static inline NodeType *getEntryNode(Type *T) { return T; } 00414 static inline ChildIteratorType child_begin(NodeType *N) { 00415 return N->subtype_begin(); 00416 } 00417 static inline ChildIteratorType child_end(NodeType *N) { 00418 return N->subtype_end(); 00419 } 00420 }; 00421 00422 template <> struct GraphTraits<const Type*> { 00423 typedef const Type NodeType; 00424 typedef Type::subtype_iterator ChildIteratorType; 00425 00426 static inline NodeType *getEntryNode(const Type *T) { return T; } 00427 static inline ChildIteratorType child_begin(NodeType *N) { 00428 return N->subtype_begin(); 00429 } 00430 static inline ChildIteratorType child_end(NodeType *N) { 00431 return N->subtype_end(); 00432 } 00433 }; 00434 00435 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) { 00436 return Ty.getTypeID() == Type::PointerTyID; 00437 } 00438 00439 std::ostream &operator<<(std::ostream &OS, const Type &T); 00440 00441 } // End llvm namespace 00442 00443 #endif