improve comments.

[oota-llvm.git] / include / llvm / AbstractTypeUser.h

diff --git a/include/llvm/AbstractTypeUser.h b/include/llvm/AbstractTypeUser.h
index f7fabfcb2fe4b4fa18559eb0130ae13019907e3a..c1216baabf8fac950ba59fcd29efd55897f0b6aa 100644 (file)
--- a/include/llvm/AbstractTypeUser.h
+++ b/include/llvm/AbstractTypeUser.h
@@ -33,6 +33,7 @@ namespace llvm {
 
 class Type;
 class DerivedType;
+template<typename T> struct simplify_type;
 
 /// The AbstractTypeUser class is an interface to be implemented by classes who
 /// could possibly use an abstract type.  Abstract types are denoted by the
@@ -136,6 +137,7 @@ public:
 ///
 class PATypeHolder {
   mutable const Type *Ty;
+  void destroy();
 public:
   PATypeHolder(const Type *ty) : Ty(ty) {
     addRef();
@@ -144,7 +146,7 @@ public:
     addRef();
   }
 
-  ~PATypeHolder() { dropRef(); }
+  ~PATypeHolder() { if (Ty) dropRef(); }
 
   operator Type *() const { return get(); }
   Type *get() const;
@@ -172,8 +174,24 @@ public:
 private:
   void addRef();
   void dropRef();
+  friend class TypeMapBase;
 };
 
+// simplify_type - Allow clients to treat uses just like values when using
+// casting operators.
+template<> struct simplify_type<PATypeHolder> {
+  typedef const Type* SimpleType;
+  static SimpleType getSimplifiedValue(const PATypeHolder &Val) {
+    return static_cast<SimpleType>(Val.get());
+  }
+};
+template<> struct simplify_type<const PATypeHolder> {
+  typedef const Type* SimpleType;
+  static SimpleType getSimplifiedValue(const PATypeHolder &Val) {
+    return static_cast<SimpleType>(Val.get());
+  }
+};
+  
 } // End llvm namespace
 
 #endif