Add support for optimization reports.

Summary:
This patch adds a new flag -Rpass=. The flag indicates the name
of the optimization pass that should emit remarks stating when it
made a transformation to the code.

This implements the design I proposed in:

https://docs.google.com/document/d/1FYUatSjZZO-zmFBxjOiuOzAy9mhHA8hqdvklZv68WuQ/edit?usp=sharing

Other changes:
- Add DiagnosticIDs::isRemark(). Use it in printDiagnosticOptions to
  print "-R" instead of "-W" in the diagnostic message.

- In BackendConsumer::OptimizationRemarkHandler, get a SourceLocation
  object out of the file name, line and column number. Use that location
  in the call to Diags.Report().

- When -Rpass is used without debug info a note is emitted alerting
  the user that they need to use -gline-tables-only -gcolumn-info to
  get this information.

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3226

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206401 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C rewriter. Use _WIN64 instead of __LLP64__
to conditinalize on 64bit length in a generated meta-data.
// rdar://16489050


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206402 91177308-0d34-0410-b5e6-96231b3b80d8
Minor cleanups for deleted functions to ensure they're a bit more robustly "deleted".

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206404 91177308-0d34-0410-b5e6-96231b3b80d8
More minor refactoring. Updated for const-correctness, moved another deleted function to be private, 0 -> nullptr and some style corrections. No functional changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@206406 91177308-0d34-0410-b5e6-96231b3b80d8