1 //===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
14 #include "llvm/AbstractTypeUser.h"
15 #include "llvm/LLVMContext.h"
16 #include "llvm/Support/Casting.h"
17 #include "llvm/Support/DataTypes.h"
18 #include "llvm/System/Atomic.h"
19 #include "llvm/ADT/GraphTraits.h"
20 #include "llvm/ADT/iterator.h"
33 /// This file contains the declaration of the Type class. For more "Type" type
34 /// stuff, look in DerivedTypes.h.
36 /// The instances of the Type class are immutable: once they are created,
37 /// they are never changed. Also note that only one instance of a particular
38 /// type is ever created. Thus seeing if two types are equal is a matter of
39 /// doing a trivial pointer comparison. To enforce that no two equal instances
40 /// are created, Type instances can only be created via static factory methods
41 /// in class Type and in derived classes.
43 /// Once allocated, Types are never free'd, unless they are an abstract type
44 /// that is resolved to a more concrete type.
46 /// Types themself don't have a name, and can be named either by:
47 /// - using SymbolTable instance, typically from some Module,
48 /// - using convenience methods in the Module class (which uses module's
51 /// Opaque types are simple derived types with no state. There may be many
52 /// different Opaque type objects floating around, but two are only considered
53 /// identical if they are pointer equals of each other. This allows us to have
54 /// two opaque types that end up resolving to different concrete types later.
56 /// Opaque types are also kinda weird and scary and different because they have
57 /// to keep a list of uses of the type. When, through linking, parsing, or
58 /// bitcode reading, they become resolved, they need to find and update all
59 /// users of the unknown type, causing them to reference a new, more concrete
60 /// type. Opaque types are deleted when their use list dwindles to zero users.
62 /// @brief Root of type hierarchy
63 class Type : public AbstractTypeUser {
65 //===-------------------------------------------------------------------===//
66 /// Definitions of all of the base types for the Type system. Based on this
67 /// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
68 /// Note: If you add an element to this, you need to add an element to the
69 /// Type::getPrimitiveType function, or else things will break!
70 /// Also update LLVMTypeKind and LLVMGetTypeKind () in the C binding.
73 // PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
74 VoidTyID = 0, ///< 0: type with no size
75 FloatTyID, ///< 1: 32 bit floating point type
76 DoubleTyID, ///< 2: 64 bit floating point type
77 X86_FP80TyID, ///< 3: 80 bit floating point type (X87)
78 FP128TyID, ///< 4: 128 bit floating point type (112-bit mantissa)
79 PPC_FP128TyID, ///< 5: 128 bit floating point type (two 64-bits)
80 LabelTyID, ///< 6: Labels
81 MetadataTyID, ///< 7: Metadata
83 // Derived types... see DerivedTypes.h file...
84 // Make sure FirstDerivedTyID stays up to date!!!
85 IntegerTyID, ///< 8: Arbitrary bit width integers
86 FunctionTyID, ///< 9: Functions
87 StructTyID, ///< 10: Structures
88 ArrayTyID, ///< 11: Arrays
89 PointerTyID, ///< 12: Pointers
90 OpaqueTyID, ///< 13: Opaque: type with unknown structure
91 VectorTyID, ///< 14: SIMD 'packed' format, or other vector type
93 NumTypeIDs, // Must remain as last defined ID
94 LastPrimitiveTyID = LabelTyID,
95 FirstDerivedTyID = IntegerTyID
99 TypeID ID : 8; // The current base type of this type.
100 bool Abstract : 1; // True if type contains an OpaqueType
101 unsigned SubclassData : 23; //Space for subclasses to store data
103 /// RefCount - This counts the number of PATypeHolders that are pointing to
104 /// this type. When this number falls to zero, if the type is abstract and
105 /// has no AbstractTypeUsers, the type is deleted. This is only sensical for
108 mutable sys::cas_flag RefCount;
110 /// Context - This refers to the LLVMContext in which this type was uniqued.
111 LLVMContext &Context;
113 const Type *getForwardedTypeInternal() const;
115 // Some Type instances are allocated as arrays, some aren't. So we provide
116 // this method to get the right kind of destruction for the type of Type.
117 void destroy() const; // const is a lie, this does "delete this"!
120 explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0),
121 RefCount(0), Context(getGlobalContext()),
122 ForwardType(0), NumContainedTys(0),
125 assert(AbstractTypeUsers.empty() && "Abstract types remain");
128 /// Types can become nonabstract later, if they are refined.
130 inline void setAbstract(bool Val) { Abstract = Val; }
132 unsigned getRefCount() const { return RefCount; }
134 unsigned getSubclassData() const { return SubclassData; }
135 void setSubclassData(unsigned val) { SubclassData = val; }
137 /// ForwardType - This field is used to implement the union find scheme for
138 /// abstract types. When types are refined to other types, this field is set
139 /// to the more refined type. Only abstract types can be forwarded.
140 mutable const Type *ForwardType;
143 /// AbstractTypeUsers - Implement a list of the users that need to be notified
144 /// if I am a type, and I get resolved into a more concrete type.
146 mutable std::vector<AbstractTypeUser *> AbstractTypeUsers;
148 /// NumContainedTys - Keeps track of how many PATypeHandle instances there
149 /// are at the end of this type instance for the list of contained types. It
150 /// is the subclasses responsibility to set this up. Set to 0 if there are no
151 /// contained types in this type.
152 unsigned NumContainedTys;
154 /// ContainedTys - A pointer to the array of Types (PATypeHandle) contained
155 /// by this Type. For example, this includes the arguments of a function
156 /// type, the elements of a structure, the pointee of a pointer, the element
157 /// type of an array, etc. This pointer may be 0 for types that don't
158 /// contain other types (Integer, Double, Float). In general, the subclass
159 /// should arrange for space for the PATypeHandles to be included in the
160 /// allocation of the type object and set this pointer to the address of the
161 /// first element. This allows the Type class to manipulate the ContainedTys
162 /// without understanding the subclass's placement for this array. keeping
163 /// it here also allows the subtype_* members to be implemented MUCH more
164 /// efficiently, and dynamically very few types do not contain any elements.
165 PATypeHandle *ContainedTys;
168 void print(raw_ostream &O) const;
169 void print(std::ostream &O) const;
171 /// @brief Debugging support: print to stderr
174 /// @brief Debugging support: print to stderr (use type names from context
176 void dump(const Module *Context) const;
178 /// getContext - Fetch the LLVMContext in which this type was uniqued.
179 LLVMContext &getContext() const { return Context; }
181 //===--------------------------------------------------------------------===//
182 // Property accessors for dealing with types... Some of these virtual methods
183 // are defined in private classes defined in Type.cpp for primitive types.
186 /// getTypeID - Return the type id for the type. This will return one
187 /// of the TypeID enum elements defined above.
189 inline TypeID getTypeID() const { return ID; }
191 /// getDescription - Return the string representation of the type.
192 std::string getDescription() const;
194 /// isInteger - True if this is an instance of IntegerType.
196 bool isInteger() const { return ID == IntegerTyID; }
198 /// isIntOrIntVector - Return true if this is an integer type or a vector of
201 bool isIntOrIntVector() const;
203 /// isFloatingPoint - Return true if this is one of the five floating point
205 bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID ||
206 ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; }
208 /// isFPOrFPVector - Return true if this is a FP type or a vector of FP types.
210 bool isFPOrFPVector() const;
212 /// isAbstract - True if the type is either an Opaque type, or is a derived
213 /// type that includes an opaque type somewhere in it.
215 inline bool isAbstract() const { return Abstract; }
217 /// canLosslesslyBitCastTo - Return true if this type could be converted
218 /// with a lossless BitCast to type 'Ty'. For example, i8* to i32*. BitCasts
219 /// are valid for types of the same size only where no re-interpretation of
220 /// the bits is done.
221 /// @brief Determine if this type could be losslessly bitcast to Ty
222 bool canLosslesslyBitCastTo(const Type *Ty) const;
225 /// Here are some useful little methods to query what type derived types are
226 /// Note that all other types can just compare to see if this == Type::xxxTy;
228 inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
229 inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
231 /// isFirstClassType - Return true if the type is "first class", meaning it
232 /// is a valid type for a Value.
234 inline bool isFirstClassType() const {
235 // There are more first-class kinds than non-first-class kinds, so a
236 // negative test is simpler than a positive one.
237 return ID != FunctionTyID && ID != VoidTyID && ID != OpaqueTyID;
240 /// isSingleValueType - Return true if the type is a valid type for a
241 /// virtual register in codegen. This includes all first-class types
242 /// except struct and array types.
244 inline bool isSingleValueType() const {
245 return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
246 ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID;
249 /// isAggregateType - Return true if the type is an aggregate type. This
250 /// means it is valid as the first operand of an insertvalue or
251 /// extractvalue instruction. This includes struct and array types, but
252 /// does not include vector types.
254 inline bool isAggregateType() const {
255 return ID == StructTyID || ID == ArrayTyID;
258 /// isSized - Return true if it makes sense to take the size of this type. To
259 /// get the actual size for a particular target, it is reasonable to use the
260 /// TargetData subsystem to do this.
262 bool isSized() const {
263 // If it's a primitive, it is always sized.
264 if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID)
266 // If it is not something that can have a size (e.g. a function or label),
267 // it doesn't have a size.
268 if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID)
270 // If it is something that can have a size and it's concrete, it definitely
271 // has a size, otherwise we have to try harder to decide.
272 return !isAbstract() || isSizedDerivedType();
275 /// getPrimitiveSizeInBits - Return the basic size of this type if it is a
276 /// primitive type. These are fixed by LLVM and are not target dependent.
277 /// This will return zero if the type does not have a size or is not a
280 /// Note that this may not reflect the size of memory allocated for an
281 /// instance of the type or the number of bytes that are written when an
282 /// instance of the type is stored to memory. The TargetData class provides
283 /// additional query functions to provide this information.
285 unsigned getPrimitiveSizeInBits() const;
287 /// getScalarSizeInBits - If this is a vector type, return the
288 /// getPrimitiveSizeInBits value for the element type. Otherwise return the
289 /// getPrimitiveSizeInBits value for this type.
290 unsigned getScalarSizeInBits() const;
292 /// getFPMantissaWidth - Return the width of the mantissa of this type. This
293 /// is only valid on floating point types. If the FP type does not
294 /// have a stable mantissa (e.g. ppc long double), this method returns -1.
295 int getFPMantissaWidth() const;
297 /// getForwardedType - Return the type that this type has been resolved to if
298 /// it has been resolved to anything. This is used to implement the
299 /// union-find algorithm for type resolution, and shouldn't be used by general
301 const Type *getForwardedType() const {
302 if (!ForwardType) return 0;
303 return getForwardedTypeInternal();
306 /// getVAArgsPromotedType - Return the type an argument of this type
307 /// will be promoted to if passed through a variable argument
309 const Type *getVAArgsPromotedType() const;
311 /// getScalarType - If this is a vector type, return the element type,
312 /// otherwise return this.
313 const Type *getScalarType() const;
315 //===--------------------------------------------------------------------===//
316 // Type Iteration support
318 typedef PATypeHandle *subtype_iterator;
319 subtype_iterator subtype_begin() const { return ContainedTys; }
320 subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];}
322 /// getContainedType - This method is used to implement the type iterator
323 /// (defined a the end of the file). For derived types, this returns the
324 /// types 'contained' in the derived type.
326 const Type *getContainedType(unsigned i) const {
327 assert(i < NumContainedTys && "Index out of range!");
328 return ContainedTys[i].get();
331 /// getNumContainedTypes - Return the number of types in the derived type.
333 unsigned getNumContainedTypes() const { return NumContainedTys; }
335 //===--------------------------------------------------------------------===//
336 // Static members exported by the Type class itself. Useful for getting
337 // instances of Type.
340 /// getPrimitiveType - Return a type based on an identifier.
341 static const Type *getPrimitiveType(TypeID IDNumber);
343 //===--------------------------------------------------------------------===//
344 // These are the builtin types that are always available...
346 static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy, *MetadataTy;
347 static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty;
348 static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty;
350 /// Methods for support type inquiry through isa, cast, and dyn_cast:
351 static inline bool classof(const Type *) { return true; }
353 void addRef() const {
354 assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
355 sys::AtomicIncrement(&RefCount);
358 void dropRef() const {
359 assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
360 assert(RefCount && "No objects are currently referencing this object!");
362 // If this is the last PATypeHolder using this object, and there are no
363 // PATypeHandles using it, the type is dead, delete it now.
364 sys::cas_flag OldCount = sys::AtomicDecrement(&RefCount);
365 if (OldCount == 0 && AbstractTypeUsers.empty())
369 /// addAbstractTypeUser - Notify an abstract type that there is a new user of
370 /// it. This function is called primarily by the PATypeHandle class.
372 void addAbstractTypeUser(AbstractTypeUser *U) const;
374 /// removeAbstractTypeUser - Notify an abstract type that a user of the class
375 /// no longer has a handle to the type. This function is called primarily by
376 /// the PATypeHandle class. When there are no users of the abstract type, it
377 /// is annihilated, because there is no way to get a reference to it ever
380 void removeAbstractTypeUser(AbstractTypeUser *U) const;
382 /// getPointerTo - Return a pointer to the current type. This is equivalent
383 /// to PointerType::get(Foo, AddrSpace).
384 PointerType *getPointerTo(unsigned AddrSpace = 0) const;
387 /// isSizedDerivedType - Derived types like structures and arrays are sized
388 /// iff all of the members of the type are sized as well. Since asking for
389 /// their size is relatively uncommon, move this operation out of line.
390 bool isSizedDerivedType() const;
392 virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
393 virtual void typeBecameConcrete(const DerivedType *AbsTy);
396 // PromoteAbstractToConcrete - This is an internal method used to calculate
397 // change "Abstract" from true to false when types are refined.
398 void PromoteAbstractToConcrete();
399 friend class TypeMapBase;
402 //===----------------------------------------------------------------------===//
403 // Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
404 // These are defined here because they MUST be inlined, yet are dependent on
405 // the definition of the Type class.
407 inline void PATypeHandle::addUser() {
408 assert(Ty && "Type Handle has a null type!");
409 if (Ty->isAbstract())
410 Ty->addAbstractTypeUser(User);
412 inline void PATypeHandle::removeUser() {
413 if (Ty->isAbstract())
414 Ty->removeAbstractTypeUser(User);
417 // Define inline methods for PATypeHolder.
419 /// get - This implements the forwarding part of the union-find algorithm for
420 /// abstract types. Before every access to the Type*, we check to see if the
421 /// type we are pointing to is forwarding to a new type. If so, we drop our
422 /// reference to the type.
424 inline Type* PATypeHolder::get() const {
425 const Type *NewTy = Ty->getForwardedType();
426 if (!NewTy) return const_cast<Type*>(Ty);
427 return *const_cast<PATypeHolder*>(this) = NewTy;
430 inline void PATypeHolder::addRef() {
431 assert(Ty && "Type Holder has a null type!");
432 if (Ty->isAbstract())
436 inline void PATypeHolder::dropRef() {
437 if (Ty->isAbstract())
442 //===----------------------------------------------------------------------===//
443 // Provide specializations of GraphTraits to be able to treat a type as a
444 // graph of sub types...
446 template <> struct GraphTraits<Type*> {
447 typedef Type NodeType;
448 typedef Type::subtype_iterator ChildIteratorType;
450 static inline NodeType *getEntryNode(Type *T) { return T; }
451 static inline ChildIteratorType child_begin(NodeType *N) {
452 return N->subtype_begin();
454 static inline ChildIteratorType child_end(NodeType *N) {
455 return N->subtype_end();
459 template <> struct GraphTraits<const Type*> {
460 typedef const Type NodeType;
461 typedef Type::subtype_iterator ChildIteratorType;
463 static inline NodeType *getEntryNode(const Type *T) { return T; }
464 static inline ChildIteratorType child_begin(NodeType *N) {
465 return N->subtype_begin();
467 static inline ChildIteratorType child_end(NodeType *N) {
468 return N->subtype_end();
472 template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
473 return Ty.getTypeID() == Type::PointerTyID;
476 std::ostream &operator<<(std::ostream &OS, const Type &T);
477 raw_ostream &operator<<(raw_ostream &OS, const Type &T);
479 } // End llvm namespace