llvm-6502/include/llvm/Type.h
2008-02-25 21:28:46 +00:00

413 lines
16 KiB
C++

//===-- llvm/Type.h - Classes for handling data types -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TYPE_H
#define LLVM_TYPE_H
#include "llvm/AbstractTypeUser.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Streams.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/iterator"
#include <string>
#include <vector>
namespace llvm {
class DerivedType;
class PointerType;
class IntegerType;
class TypeMapBase;
/// This file contains the declaration of the Type class. For more "Type" type
/// stuff, look in DerivedTypes.h.
///
/// The instances of the Type class are immutable: once they are created,
/// they are never changed. Also note that only one instance of a particular
/// type is ever created. Thus seeing if two types are equal is a matter of
/// doing a trivial pointer comparison. To enforce that no two equal instances
/// are created, Type instances can only be created via static factory methods
/// in class Type and in derived classes.
///
/// Once allocated, Types are never free'd, unless they are an abstract type
/// that is resolved to a more concrete type.
///
/// Types themself don't have a name, and can be named either by:
/// - using SymbolTable instance, typically from some Module,
/// - using convenience methods in the Module class (which uses module's
/// SymbolTable too).
///
/// Opaque types are simple derived types with no state. There may be many
/// different Opaque type objects floating around, but two are only considered
/// identical if they are pointer equals of each other. This allows us to have
/// two opaque types that end up resolving to different concrete types later.
///
/// Opaque types are also kinda weird and scary and different because they have
/// to keep a list of uses of the type. When, through linking, parsing, or
/// bitcode reading, they become resolved, they need to find and update all
/// users of the unknown type, causing them to reference a new, more concrete
/// type. Opaque types are deleted when their use list dwindles to zero users.
///
/// @brief Root of type hierarchy
class Type : public AbstractTypeUser {
public:
//===-------------------------------------------------------------------===//
/// Definitions of all of the base types for the Type system. Based on this
/// value, you can cast to a "DerivedType" subclass (see DerivedTypes.h)
/// Note: If you add an element to this, you need to add an element to the
/// Type::getPrimitiveType function, or else things will break!
///
enum TypeID {
// PrimitiveTypes .. make sure LastPrimitiveTyID stays up to date
VoidTyID = 0, ///< 0: type with no size
FloatTyID, ///< 1: 32 bit floating point type
DoubleTyID, ///< 2: 64 bit floating point type
X86_FP80TyID, ///< 3: 80 bit floating point type (X87)
FP128TyID, ///< 4: 128 bit floating point type (112-bit mantissa)
PPC_FP128TyID, ///< 5: 128 bit floating point type (two 64-bits)
LabelTyID, ///< 6: Labels
// Derived types... see DerivedTypes.h file...
// Make sure FirstDerivedTyID stays up to date!!!
IntegerTyID, ///< 7: Arbitrary bit width integers
FunctionTyID, ///< 8: Functions
StructTyID, ///< 9: Structures
ArrayTyID, ///< 10: Arrays
PointerTyID, ///< 11: Pointers
OpaqueTyID, ///< 12: Opaque: type with unknown structure
VectorTyID, ///< 13: SIMD 'packed' format, or other vector type
NumTypeIDs, // Must remain as last defined ID
LastPrimitiveTyID = LabelTyID,
FirstDerivedTyID = IntegerTyID
};
private:
TypeID ID : 8; // The current base type of this type.
bool Abstract : 1; // True if type contains an OpaqueType
unsigned SubclassData : 23; //Space for subclasses to store data
/// RefCount - This counts the number of PATypeHolders that are pointing to
/// this type. When this number falls to zero, if the type is abstract and
/// has no AbstractTypeUsers, the type is deleted. This is only sensical for
/// derived types.
///
mutable unsigned RefCount;
const Type *getForwardedTypeInternal() const;
// Some Type instances are allocated as arrays, some aren't. So we provide
// this method to get the right kind of destruction for the type of Type.
void destroy() const; // const is a lie, this does "delete this"!
protected:
explicit Type(TypeID id) : ID(id), Abstract(false), SubclassData(0),
RefCount(0), ForwardType(0), NumContainedTys(0),
ContainedTys(0) {}
virtual ~Type() {
assert(AbstractTypeUsers.empty() && "Abstract types remain");
}
/// Types can become nonabstract later, if they are refined.
///
inline void setAbstract(bool Val) { Abstract = Val; }
unsigned getRefCount() const { return RefCount; }
unsigned getSubclassData() const { return SubclassData; }
void setSubclassData(unsigned val) { SubclassData = val; }
/// ForwardType - This field is used to implement the union find scheme for
/// abstract types. When types are refined to other types, this field is set
/// to the more refined type. Only abstract types can be forwarded.
mutable const Type *ForwardType;
/// AbstractTypeUsers - Implement a list of the users that need to be notified
/// if I am a type, and I get resolved into a more concrete type.
///
mutable std::vector<AbstractTypeUser *> AbstractTypeUsers;
/// NumContainedTys - Keeps track of how many PATypeHandle instances there
/// are at the end of this type instance for the list of contained types. It
/// is the subclasses responsibility to set this up. Set to 0 if there are no
/// contained types in this type.
unsigned NumContainedTys;
/// ContainedTys - A pointer to the array of Types (PATypeHandle) contained
/// by this Type. For example, this includes the arguments of a function
/// type, the elements of a structure, the pointee of a pointer, the element
/// type of an array, etc. This pointer may be 0 for types that don't
/// contain other types (Integer, Double, Float). In general, the subclass
/// should arrange for space for the PATypeHandles to be included in the
/// allocation of the type object and set this pointer to the address of the
/// first element. This allows the Type class to manipulate the ContainedTys
/// without understanding the subclass's placement for this array. keeping
/// it here also allows the subtype_* members to be implemented MUCH more
/// efficiently, and dynamically very few types do not contain any elements.
PATypeHandle *ContainedTys;
public:
void print(std::ostream &O) const;
void print(std::ostream *O) const { if (O) print(*O); }
/// @brief Debugging support: print to stderr
void dump() const;
//===--------------------------------------------------------------------===//
// Property accessors for dealing with types... Some of these virtual methods
// are defined in private classes defined in Type.cpp for primitive types.
//
/// getTypeID - Return the type id for the type. This will return one
/// of the TypeID enum elements defined above.
///
inline TypeID getTypeID() const { return ID; }
/// getDescription - Return the string representation of the type...
const std::string &getDescription() const;
/// isInteger - True if this is an instance of IntegerType.
///
bool isInteger() const { return ID == IntegerTyID; }
/// isIntOrIntVector - Return true if this is an integer type or a vector of
/// integer types.
///
bool isIntOrIntVector() const;
/// isFloatingPoint - Return true if this is one of the two floating point
/// types
bool isFloatingPoint() const { return ID == FloatTyID || ID == DoubleTyID ||
ID == X86_FP80TyID || ID == FP128TyID || ID == PPC_FP128TyID; }
/// isFPOrFPVector - Return true if this is a FP type or a vector of FP types.
///
bool isFPOrFPVector() const;
/// isAbstract - True if the type is either an Opaque type, or is a derived
/// type that includes an opaque type somewhere in it.
///
inline bool isAbstract() const { return Abstract; }
/// canLosslesslyBitCastTo - Return true if this type could be converted
/// with a lossless BitCast to type 'Ty'. For example, uint to int. BitCasts
/// are valid for types of the same size only where no re-interpretation of
/// the bits is done.
/// @brief Determine if this type could be losslessly bitcast to Ty
bool canLosslesslyBitCastTo(const Type *Ty) const;
/// Here are some useful little methods to query what type derived types are
/// Note that all other types can just compare to see if this == Type::xxxTy;
///
inline bool isPrimitiveType() const { return ID <= LastPrimitiveTyID; }
inline bool isDerivedType() const { return ID >= FirstDerivedTyID; }
/// isFirstClassType - Return true if the value is holdable in a register.
///
inline bool isFirstClassType() const {
return (ID != VoidTyID && ID <= LastPrimitiveTyID) ||
ID == IntegerTyID || ID == PointerTyID || ID == VectorTyID;
}
/// isSized - Return true if it makes sense to take the size of this type. To
/// get the actual size for a particular target, it is reasonable to use the
/// TargetData subsystem to do this.
///
bool isSized() const {
// If it's a primitive, it is always sized.
if (ID == IntegerTyID || isFloatingPoint() || ID == PointerTyID)
return true;
// If it is not something that can have a size (e.g. a function or label),
// it doesn't have a size.
if (ID != StructTyID && ID != ArrayTyID && ID != VectorTyID)
return false;
// If it is something that can have a size and it's concrete, it definitely
// has a size, otherwise we have to try harder to decide.
return !isAbstract() || isSizedDerivedType();
}
/// getPrimitiveSizeInBits - Return the basic size of this type if it is a
/// primitive type. These are fixed by LLVM and are not target dependent.
/// This will return zero if the type does not have a size or is not a
/// primitive type.
///
unsigned getPrimitiveSizeInBits() const;
/// getForwardedType - Return the type that this type has been resolved to if
/// it has been resolved to anything. This is used to implement the
/// union-find algorithm for type resolution, and shouldn't be used by general
/// purpose clients.
const Type *getForwardedType() const {
if (!ForwardType) return 0;
return getForwardedTypeInternal();
}
/// getVAArgsPromotedType - Return the type an argument of this type
/// will be promoted to if passed through a variable argument
/// function.
const Type *getVAArgsPromotedType() const;
//===--------------------------------------------------------------------===//
// Type Iteration support
//
typedef PATypeHandle *subtype_iterator;
subtype_iterator subtype_begin() const { return ContainedTys; }
subtype_iterator subtype_end() const { return &ContainedTys[NumContainedTys];}
/// getContainedType - This method is used to implement the type iterator
/// (defined a the end of the file). For derived types, this returns the
/// types 'contained' in the derived type.
///
const Type *getContainedType(unsigned i) const {
assert(i < NumContainedTys && "Index out of range!");
return ContainedTys[i].get();
}
/// getNumContainedTypes - Return the number of types in the derived type.
///
unsigned getNumContainedTypes() const { return NumContainedTys; }
//===--------------------------------------------------------------------===//
// Static members exported by the Type class itself. Useful for getting
// instances of Type.
//
/// getPrimitiveType - Return a type based on an identifier.
static const Type *getPrimitiveType(TypeID IDNumber);
//===--------------------------------------------------------------------===//
// These are the builtin types that are always available...
//
static const Type *VoidTy, *LabelTy, *FloatTy, *DoubleTy;
static const Type *X86_FP80Ty, *FP128Ty, *PPC_FP128Ty;
static const IntegerType *Int1Ty, *Int8Ty, *Int16Ty, *Int32Ty, *Int64Ty;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Type *T) { return true; }
void addRef() const {
assert(isAbstract() && "Cannot add a reference to a non-abstract type!");
++RefCount;
}
void dropRef() const {
assert(isAbstract() && "Cannot drop a reference to a non-abstract type!");
assert(RefCount && "No objects are currently referencing this object!");
// If this is the last PATypeHolder using this object, and there are no
// PATypeHandles using it, the type is dead, delete it now.
if (--RefCount == 0 && AbstractTypeUsers.empty())
this->destroy();
}
/// addAbstractTypeUser - Notify an abstract type that there is a new user of
/// it. This function is called primarily by the PATypeHandle class.
///
void addAbstractTypeUser(AbstractTypeUser *U) const {
assert(isAbstract() && "addAbstractTypeUser: Current type not abstract!");
AbstractTypeUsers.push_back(U);
}
/// removeAbstractTypeUser - Notify an abstract type that a user of the class
/// no longer has a handle to the type. This function is called primarily by
/// the PATypeHandle class. When there are no users of the abstract type, it
/// is annihilated, because there is no way to get a reference to it ever
/// again.
///
void removeAbstractTypeUser(AbstractTypeUser *U) const;
private:
/// isSizedDerivedType - Derived types like structures and arrays are sized
/// iff all of the members of the type are sized as well. Since asking for
/// their size is relatively uncommon, move this operation out of line.
bool isSizedDerivedType() const;
virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy);
virtual void typeBecameConcrete(const DerivedType *AbsTy);
protected:
// PromoteAbstractToConcrete - This is an internal method used to calculate
// change "Abstract" from true to false when types are refined.
void PromoteAbstractToConcrete();
friend class TypeMapBase;
};
//===----------------------------------------------------------------------===//
// Define some inline methods for the AbstractTypeUser.h:PATypeHandle class.
// These are defined here because they MUST be inlined, yet are dependent on
// the definition of the Type class.
//
inline void PATypeHandle::addUser() {
assert(Ty && "Type Handle has a null type!");
if (Ty->isAbstract())
Ty->addAbstractTypeUser(User);
}
inline void PATypeHandle::removeUser() {
if (Ty->isAbstract())
Ty->removeAbstractTypeUser(User);
}
// Define inline methods for PATypeHolder.
inline void PATypeHolder::addRef() {
assert(Ty && "Type Holder has a null type!");
if (Ty->isAbstract())
Ty->addRef();
}
inline void PATypeHolder::dropRef() {
if (Ty->isAbstract())
Ty->dropRef();
}
//===----------------------------------------------------------------------===//
// Provide specializations of GraphTraits to be able to treat a type as a
// graph of sub types...
template <> struct GraphTraits<Type*> {
typedef Type NodeType;
typedef Type::subtype_iterator ChildIteratorType;
static inline NodeType *getEntryNode(Type *T) { return T; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->subtype_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->subtype_end();
}
};
template <> struct GraphTraits<const Type*> {
typedef const Type NodeType;
typedef Type::subtype_iterator ChildIteratorType;
static inline NodeType *getEntryNode(const Type *T) { return T; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->subtype_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->subtype_end();
}
};
template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
return Ty.getTypeID() == Type::PointerTyID;
}
std::ostream &operator<<(std::ostream &OS, const Type &T);
} // End llvm namespace
#endif