Apply Jeffrey Yasskin's CallbackVH patch, with minor tweaks from me

to make the copy constructor and destructor protected, and corresponding
adjustments to the unittests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70644 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp
index af3f4e7078..35c8ccfae6 100644
--- a/lib/VMCore/Value.cpp
+++ b/lib/VMCore/Value.cpp
@@ -511,7 +511,9 @@ void ValueHandleBase::ValueIsDeleted(Value *V) {
       ThisNode->operator=(0);
       break;
     case Callback:
-      assert(0 && "Callback not implemented yet!");
+      // Forward to the subclass's implementation.
+      static_cast<CallbackVH*>(ThisNode)->deleted();
+      break;
     }
   }
   
@@ -543,11 +545,17 @@ void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
       ThisNode->operator=(New);
       break;
     case Callback:
-      assert(0 && "Callback not implemented yet!");
+      // Forward to the subclass's implementation.
+      static_cast<CallbackVH*>(ThisNode)->allUsesReplacedWith(New);
+      break;
     }
   }
 }
 
+/// ~CallbackVH. Empty, but defined here to avoid emitting the vtable
+/// more than once.
+CallbackVH::~CallbackVH() {}
+
 
 //===----------------------------------------------------------------------===//
 //                                 User Class