Adding some comments about AST node requirements for attributes which create AST nodes but never actually make use of them. No functional changes.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197582 91177308-0d34-0410-b5e6-96231b3b80d8
Implement the MSABI and SysVABI calling conventions for Objective-C method declarations. This appears to be an omission from r189644.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197584 91177308-0d34-0410-b5e6-96231b3b80d8
clang-format parts of the file.

I am about to send a patch for review touching these and clang-formating first
makes the patch much easier to read.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197585 91177308-0d34-0410-b5e6-96231b3b80d8
ObjectiveC. Fixes the sentence in a diagnostic.
// rdar://15397430


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197586 91177308-0d34-0410-b5e6-96231b3b80d8