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