//===-- 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
//
#include <cassert>
+namespace llvm {
+
class Type;
class DerivedType;
class AbstractTypeUser {
protected:
- virtual ~AbstractTypeUser() {} // Derive from me
+ virtual ~AbstractTypeUser(); // Derive from me
public:
- // refineAbstractType - The callback method invoked when an abstract type
- // has been found to be more concrete. A class must override this method to
- // update its internal state to reference NewType instead of OldType. Soon
- // after this method is invoked, OldType shall be deleted, so referencing it
- // is quite unwise.
- //
- // Another case that is important to consider is when a type is refined, but
- // stays in the same place in memory. In this case OldTy will equal NewTy.
- // This callback just notifies ATU's that the underlying structure of the type
- // has changed... but any previously used properties are still valid.
- //
- // Note that it is possible to refine a type with parameters OldTy==NewTy, and
- // OldTy is no longer abstract. In this case, abstract type users should
- // release their hold on a type, because it went from being abstract to
- // concrete.
- //
+ /// 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;
+ 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.
-//
+/// 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;
void removeUser();
public:
// ctor - Add use to type if abstract. Note that Ty must not be null
- inline PATypeHandle(const Type *ty, AbstractTypeUser *user)
+ inline PATypeHandle(const Type *ty, AbstractTypeUser *user)
: Ty(ty), User(user) {
addUser();
}
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; }
+ inline operator Type *() const { return const_cast<Type*>(Ty); }
+ inline Type *get() const { return const_cast<Type*>(Ty); }
// operator= - Allow assignment to handle
- inline const Type *operator=(const Type *ty) {
+ inline Type *operator=(const Type *ty) {
if (Ty != ty) { // Ensure we don't accidentally drop last ref to Ty
removeUser();
Ty = ty;
addUser();
}
- return Ty;
+ return get();
}
// operator= - Allow assignment to handle
};
-// PATypeHolder - Holder class for a potentially abstract type. This functions
-// as both a handle (as above) and an AbstractTypeUser. It uses the callback to
-// keep its pointer member updated to the current version of the type.
-//
-class PATypeHolder : public AbstractTypeUser {
- PATypeHandle Handle;
+/// 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) : Handle(ty, this) {}
- PATypeHolder(const PATypeHolder &T) : AbstractTypeUser(), Handle(T, this) {}
-
- operator const Type *() const { return Handle; }
- const Type *get() const { return Handle; }
-
- // operator-> - Allow user to dereference handle naturally...
- inline const Type *operator->() const { return Handle; }
-
- // refineAbstractType - All we do is update our PATypeHandle member to point
- // to the new type.
- //
- virtual void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
- assert(get() == (const Type*)OldTy && "Can't refine to unknown value!");
+ PATypeHolder(const Type *ty) : Ty(ty) {
+ addRef();
+ }
+ PATypeHolder(const PATypeHolder &T) : Ty(T.Ty) {
+ addRef();
+ }
- // Check to see if the type just became concrete. If so, we have to
- // removeUser to get off its AbstractTypeUser list
- Handle.removeUserFromConcrete();
+ ~PATypeHolder() { dropRef(); }
- if ((const Type*)OldTy != NewTy)
- Handle.operator=(NewTy);
- }
+ operator Type *() const { return get(); }
+ Type *get() const;
- // operator= - Allow assignment to handle
- const Type *operator=(const Type *ty) {
- return Handle = ty;
- }
+ // operator-> - Allow user to dereference handle naturally...
+ Type *operator->() const { return get(); }
// operator= - Allow assignment to handle
- const Type *operator=(const PATypeHandle &T) {
- return Handle = T;
+ 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 Handle = H;
+ Type *operator=(const PATypeHolder &H) {
+ return operator=(H.Ty);
}
- void dump() const;
+ /// getRawType - This should only be used to implement the vmcore library.
+ ///
+ const Type *getRawType() const { return Ty; }
+
+private:
+ void addRef();
+ void dropRef();
};
+} // End llvm namespace
+
#endif
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