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//===-- llvm/AbstractTypeUser.h - AbstractTypeUser Interface ----*- C++ -*-===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file declares the AbstractTypeUser class.
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ABSTRACT_TYPE_USER_H
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#define LLVM_ABSTRACT_TYPE_USER_H
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#if !defined(LLVM_TYPE_H) && !defined(LLVM_VALUE_H)
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#error Do not include this file directly. Include Type.h instead.
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#error Some versions of GCC (e.g. 3.4 and 4.1) can not handle the inlined method
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#error PATypeHolder::dropRef() correctly otherwise.
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// This is the "master" include for <cassert> Whether this file needs it or not,
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// it must always include <cassert> for the files which include
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// llvm/AbstractTypeUser.h
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// In this way, most every LLVM source file will have access to the assert()
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// macro without having to #include <cassert> directly.
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template<typename T> struct simplify_type;
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/// The AbstractTypeUser class is an interface to be implemented by classes who
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/// could possibly use an abstract type. Abstract types are denoted by the
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/// isAbstract flag set to true in the Type class. These are classes that
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/// contain an Opaque type in their structure somewhere.
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/// Classes must implement this interface so that they may be notified when an
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/// abstract type is resolved. Abstract types may be resolved into more
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/// concrete types through: linking, parsing, and bitcode reading. When this
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/// happens, all of the users of the type must be updated to reference the new,
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/// more concrete type. They are notified through the AbstractTypeUser
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/// In addition to this, AbstractTypeUsers must keep the use list of the
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/// potentially abstract type that they reference up-to-date. To do this in a
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/// nice, transparent way, the PATypeHandle class is used to hold "Potentially
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/// Abstract Types", and keep the use list of the abstract types up-to-date.
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/// @brief LLVM Abstract Type User Representation
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class AbstractTypeUser {
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virtual ~AbstractTypeUser(); // Derive from me
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/// setType - It's normally not possible to change a Value's type in place,
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/// but an AbstractTypeUser subclass that knows what its doing can be
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/// permitted to do so with care.
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void setType(Value *V, const Type *NewTy);
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/// refineAbstractType - The callback method invoked when an abstract type is
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/// resolved to another type. An object must override this method to update
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/// its internal state to reference NewType instead of OldType.
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virtual void refineAbstractType(const DerivedType *OldTy,
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const Type *NewTy) = 0;
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/// The other case which AbstractTypeUsers must be aware of is when a type
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/// makes the transition from being abstract (where it has clients on its
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/// AbstractTypeUsers list) to concrete (where it does not). This method
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/// notifies ATU's when this occurs for a type.
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virtual void typeBecameConcrete(const DerivedType *AbsTy) = 0;
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virtual void dump() const = 0;
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/// PATypeHandle - Handle to a Type subclass. This class is used to keep the
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/// use list of abstract types up-to-date.
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AbstractTypeUser * const User;
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// These functions are defined at the bottom of Type.h. See the comment there
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// ctor - Add use to type if abstract. Note that Ty must not be null
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inline PATypeHandle(const Type *ty, AbstractTypeUser *user)
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: Ty(ty), User(user) {
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// ctor - Add use to type if abstract.
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inline PATypeHandle(const PATypeHandle &T) : Ty(T.Ty), User(T.User) {
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// dtor - Remove reference to type...
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inline ~PATypeHandle() { removeUser(); }
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// Automatic casting operator so that the handle may be used naturally
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inline operator Type *() const { return const_cast<Type*>(Ty); }
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inline Type *get() const { return const_cast<Type*>(Ty); }
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// operator= - Allow assignment to handle
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inline Type *operator=(const Type *ty) {
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if (Ty != ty) { // Ensure we don't accidentally drop last ref to Ty
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// operator= - Allow assignment to handle
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inline const Type *operator=(const PATypeHandle &T) {
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return operator=(T.Ty);
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inline bool operator==(const Type *ty) {
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// operator-> - Allow user to dereference handle naturally...
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inline const Type *operator->() const { return Ty; }
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/// PATypeHolder - Holder class for a potentially abstract type. This uses
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/// efficient union-find techniques to handle dynamic type resolution. Unless
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/// you need to do custom processing when types are resolved, you should always
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/// use PATypeHolders in preference to PATypeHandles.
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mutable const Type *Ty;
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PATypeHolder() : Ty(0) {}
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PATypeHolder(const Type *ty) : Ty(ty) {
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PATypeHolder(const PATypeHolder &T) : Ty(T.Ty) {
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~PATypeHolder() { dropRef(); }
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operator Type *() const { return get(); }
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// operator-> - Allow user to dereference handle naturally...
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Type *operator->() const { return get(); }
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// operator= - Allow assignment to handle
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Type *operator=(const Type *ty) {
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if (Ty != ty) { // Don't accidentally drop last ref to Ty.
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Type *operator=(const PATypeHolder &H) {
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return operator=(H.Ty);
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/// getRawType - This should only be used to implement the vmcore library.
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const Type *getRawType() const { return Ty; }
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friend class TypeMapBase;
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// simplify_type - Allow clients to treat uses just like values when using
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// casting operators.
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template<> struct simplify_type<PATypeHolder> {
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typedef const Type* SimpleType;
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static SimpleType getSimplifiedValue(const PATypeHolder &Val) {
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return static_cast<SimpleType>(Val.get());
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template<> struct simplify_type<const PATypeHolder> {
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typedef const Type* SimpleType;
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static SimpleType getSimplifiedValue(const PATypeHolder &Val) {
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return static_cast<SimpleType>(Val.get());
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} // End llvm namespace