| //===-- llvm/AbstractTypeUser.h - AbstractTypeUser Interface ----*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // The AbstractTypeUser class is an interface to be implemented by classes who |
| // could possible use an abstract type. Abstract types are denoted by the |
| // isAbstract flag set to true in the Type class. These are classes that |
| // contain an Opaque type in their structure somehow. |
| // |
| // Classes must implement this interface so that they may be notified when an |
| // abstract type is resolved. Abstract types may be resolved into more concrete |
| // types through: linking, parsing, and bytecode reading. When this happens, |
| // all of the users of the type must be updated to reference the new, more |
| // concrete type. They are notified through the AbstractTypeUser interface. |
| // |
| // In addition to this, AbstractTypeUsers must keep the use list of the |
| // potentially abstract type that they reference up-to-date. To do this in a |
| // nice, transparent way, the PATypeHandle class is used to hold "Potentially |
| // Abstract Types", and keep the use list of the abstract types up-to-date. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ABSTRACT_TYPE_USER_H |
| #define LLVM_ABSTRACT_TYPE_USER_H |
| |
| // This is the "master" include for <cassert> Whether this file needs it or not, |
| // it must always include <cassert> for the files which include |
| // llvm/AbstractTypeUser.h |
| // |
| // In this way, most every LLVM source file will have access to the assert() |
| // macro without having to #include <cassert> directly. |
| // |
| #include <cassert> |
| |
| namespace llvm { |
| |
| class Type; |
| class DerivedType; |
| |
| class AbstractTypeUser { |
| protected: |
| virtual ~AbstractTypeUser() {} // Derive from me |
| public: |
| |
| /// refineAbstractType - The callback method invoked when an abstract type is |
| /// resolved to another type. An object must override this method to update |
| /// its internal state to reference NewType instead of OldType. |
| /// |
| virtual void refineAbstractType(const DerivedType *OldTy, |
| const Type *NewTy) = 0; |
| |
| /// The other case which AbstractTypeUsers must be aware of is when a type |
| /// makes the transition from being abstract (where it has clients on it's |
| /// AbstractTypeUsers list) to concrete (where it does not). This method |
| /// notifies ATU's when this occurs for a type. |
| /// |
| virtual void typeBecameConcrete(const DerivedType *AbsTy) = 0; |
| |
| // for debugging... |
| virtual void dump() const = 0; |
| }; |
| |
| |
| /// PATypeHandle - Handle to a Type subclass. This class is used to keep the |
| /// use list of abstract types up-to-date. |
| /// |
| class PATypeHandle { |
| const Type *Ty; |
| AbstractTypeUser * const User; |
| |
| // These functions are defined at the bottom of Type.h. See the comment there |
| // for justification. |
| void addUser(); |
| void removeUser(); |
| public: |
| // ctor - Add use to type if abstract. Note that Ty must not be null |
| inline PATypeHandle(const Type *ty, AbstractTypeUser *user) |
| : Ty(ty), User(user) { |
| addUser(); |
| } |
| |
| // ctor - Add use to type if abstract. |
| inline PATypeHandle(const PATypeHandle &T) : Ty(T.Ty), User(T.User) { |
| addUser(); |
| } |
| |
| // dtor - Remove reference to type... |
| inline ~PATypeHandle() { removeUser(); } |
| |
| // Automatic casting operator so that the handle may be used naturally |
| inline operator const Type *() const { return Ty; } |
| inline const Type *get() const { return Ty; } |
| |
| // operator= - Allow assignment to handle |
| inline const Type *operator=(const Type *ty) { |
| if (Ty != ty) { // Ensure we don't accidentally drop last ref to Ty |
| removeUser(); |
| Ty = ty; |
| addUser(); |
| } |
| return Ty; |
| } |
| |
| // operator= - Allow assignment to handle |
| inline const Type *operator=(const PATypeHandle &T) { |
| return operator=(T.Ty); |
| } |
| |
| inline bool operator==(const Type *ty) { |
| return Ty == ty; |
| } |
| |
| // operator-> - Allow user to dereference handle naturally... |
| inline const Type *operator->() const { return Ty; } |
| |
| // removeUserFromConcrete - This function should be called when the User is |
| // notified that our type is refined... and the type is being refined to |
| // itself, which is now a concrete type. When a type becomes concrete like |
| // this, we MUST remove ourself from the AbstractTypeUser list, even though |
| // the type is apparently concrete. |
| // |
| void removeUserFromConcrete(); |
| }; |
| |
| |
| /// PATypeHolder - Holder class for a potentially abstract type. This uses |
| /// efficient union-find techniques to handle dynamic type resolution. Unless |
| /// you need to do custom processing when types are resolved, you should always |
| /// use PATypeHolders in preference to PATypeHandles. |
| /// |
| class PATypeHolder { |
| mutable const Type *Ty; |
| public: |
| PATypeHolder(const Type *ty) : Ty(ty) { |
| addRef(); |
| } |
| PATypeHolder(const PATypeHolder &T) : Ty(T.Ty) { |
| addRef(); |
| } |
| |
| operator const Type *() const { return get(); } |
| const Type *get() const; |
| |
| // operator-> - Allow user to dereference handle naturally... |
| const Type *operator->() const { return get(); } |
| |
| // operator= - Allow assignment to handle |
| const Type *operator=(const Type *ty) { |
| if (Ty != ty) { // Don't accidentally drop last ref to Ty. |
| dropRef(); |
| Ty = ty; |
| addRef(); |
| } |
| return get(); |
| } |
| const Type *operator=(const PATypeHolder &H) { |
| return operator=(H.Ty); |
| } |
| |
| private: |
| void addRef(); |
| void dropRef(); |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |