[weak vtables] Place class definitions into anonymous namespaces to prevent weak vtables.

This patch places class definitions in implementation files into anonymous
namespaces to prevent weak vtables. This eliminates the need of providing an
out-of-line definition to pin the vtable explicitly to the file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195092 91177308-0d34-0410-b5e6-96231b3b80d8
Add an abstraction to handle patchpoint operands.

Hard-coded operand indices were scattered throughout lowering stages
and layers. It was super bug prone.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195093 91177308-0d34-0410-b5e6-96231b3b80d8
Use symbolic operands in the patchpoint folding routine and fix a spilling bug.

Fixes <rdar://15487687> [JS] AnyRegCC argument ends up being spilled

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195094 91177308-0d34-0410-b5e6-96231b3b80d8