[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
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 3144dfe..e71c4df 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/lib/CodeGen/MachineScheduler.cpp
@@ -72,6 +72,10 @@
 // DAG subtrees must have at least this many nodes.
 static const unsigned MinSubtreeSize = 8;
 
+// Pin the vtables to this file.
+void MachineSchedStrategy::anchor() {}
+void ScheduleDAGMutation::anchor() {}
+
 //===----------------------------------------------------------------------===//
 // Machine Instruction Scheduling Pass and Registry
 //===----------------------------------------------------------------------===//