[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

include/llvm/ExecutionEngine/ObjectCache.h

@@ -20,6 +20,7 @@ class Module;
 /// ExecutionEngine for the purpose of avoiding compilation for Modules that
 /// have already been compiled and an object file is available.
 class ObjectCache {
+  virtual void anchor();
 public:
   ObjectCache() { }