Formatter: Initial support for formatting Objective-C method expressions.        
                                                                                 
This follows the approach suggested by djasper in PR14911: When a '[' is         
seen that's at the start of a line, follows a binary operator, or follows one    
of : [ ( return throw, that '[' and its closing ']' are marked as
TT_ObjCMethodExpr and every ':' in that range that isn't part of a ternary
?: is marked as TT_ObjCMethodExpr as well.

Update the layout routines to not output spaces around ':' tokens that are
marked TT_ObjCMethodExpr, and only allow breaking after such tokens, not
before.

Before:
    [self adjustButton : closeButton_ ofKind : NSWindowCloseButton];

Now:
    [self adjustButton:closeButton_ ofKind:NSWindowCloseButton];



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172304 91177308-0d34-0410-b5e6-96231b3b80d8
Disable caching of visibility.

The testcase in pr14929 shows that this is extremely hard to do. If we choose
to apply the attribute, that causes the visibility of some decls to change and
that can happen really late (during codegen).

Current gcc warns and ignores the attribute in this testcase with a warning.
This suggest that the correct solution is to find a point in the compilation
where we can compute the visibility and
* assert it was never computed before
* reject any attempts to compute it again in the future (with warnings).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172305 91177308-0d34-0410-b5e6-96231b3b80d8