[weak vtables] Remove a bunch of weak vtables

This patch removes most of the trivial cases of weak vtables by pinning them to
a single object file. The memory leaks in this version have been fixed. Thanks
Alexey for pointing them out.

Differential Revision: http://llvm-reviews.chandlerc.com/D2068

Reviewed by Andy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195064 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/YAMLTraits.cpp

@@ -60,6 +60,11 @@ error_code Input::error() {
   return EC;
 }
 
+// Pin the vtables to this file.
+void Input::HNode::anchor() {}
+void Input::EmptyHNode::anchor() {}
+void Input::ScalarHNode::anchor() {}
+
 bool Input::outputting() const {
   return false;
 }