Support __PRETTY_FUNCTION__ and friends in Obj-C methods.

Add CodeGenFunction::EmitUnsupportedLValue 
 - Gives error and returns undef value.

Swap some asserts() over to using EmitUnsupportedLValue
 - Rumor has it users (and even some developers) prefer carat
   diagnostics to backtraces.
 - Works better in Release-Asserts to boot.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@55328 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed