objective-c - This patch buffers method implementations

and does the Sema on their body after the entire 
class/category @implementation is seen. This change allows messaging 
of forward private methods, as well as, access to 
synthesized ivars of properties with foward synthesize
declarations; among others. In effect, this patch removes
several restrictions placed on objective-c due to in-place
semantics processing of methods.
This is part of // rdar://8843851.

llvm-svn: 138865