Make MDNode use CallbackVH. Also change MDNode to store Value* instead of
Constant* in preperation of a future change to support holding non-Constants
in an MDNode.
llvm-svn: 71407
diff --git a/llvm/docs/LangRef.html b/llvm/docs/LangRef.html
index 36eae71..3f16e38 100644
--- a/llvm/docs/LangRef.html
+++ b/llvm/docs/LangRef.html
@@ -2061,6 +2061,10 @@
exclamation point). For example: "<tt>!{ { } !"test\00", i32 10}</tt>".
</p>
+<p>A metadata node will attempt to track changes to the values it holds. In
+the event that a value is deleted, it will be replaced with a typeless
+"<tt>null</tt>", such as "<tt>{ } !{null, i32 0}</tt>".</p>
+
<p>Optimizations may rely on metadata to provide additional information about
the program that isn't available in the instructions, or that isn't easily
computable. Similarly, the code generator may expect a certain metadata format