unique_ptr-ify PathDiagnosticPiece ownership

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216751 91177308-0d34-0410-b5e6-96231b3b80d8
unique_ptrify PathDiagnostic::setEndOfPath's argument

Again, if shared ownership is the right model here (I assume it is,
given graph algorithms & such) this could be tidied up (the 'release'
call removed in favor of something safer) by having
IntrunsiveRefCntPointer constructible from a unique_ptr.

(& honestly I'd probably favor taking a page out of shared_ptr's book,
allowing implicit construction from a unique_ptr rvalue, and only allow
explicit from a raw pointer - currently IntrusiveRefCntPointer can
implicitly own from a raw pointer, which seems unsafe)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216752 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C. Tweak diagnosing properties that are not auto-synthesized.
Do not warn when property declared in class's protocol will be auto-synthesized
by its uper class implementation because super class has also declared this
property while this class has not. Continue to warn if current class
has declared the property also (because this declaration will not result
in a 2nd synthesis).
rdar://18152478


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216753 91177308-0d34-0410-b5e6-96231b3b80d8
unique_ptrify the diagnostics in CXDiagnosticSetImpl

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216754 91177308-0d34-0410-b5e6-96231b3b80d8