Initial patch to support definitions of id and Class from headers in Objective-C code.

This currently breaks test/SemaObjC/id-isa-ref.m and issues some spurious warnings when you attempt to assign a struct objc_class* value to a Class variable.  The test case probably should fail as it's written, because without the definition of Class the compiler should not assume struct objc_class* is a valid receiver type, but it's left broken because it would be nice if we could get that passing too for the special case of isa.

Approved by snaroff.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@79248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 53a5f6d..5425c4f 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -159,6 +159,7 @@
       );
     PushOnScopeChains(IdTypedef, TUScope);
     Context.setObjCIdType(Context.getTypeDeclType(IdTypedef));
+    Context.ObjCIdRedefinitionType = Context.getObjCIdType();
   }
   // Create the built-in typedef for 'Class'.
   if (Context.getObjCClassType().isNull()) {
@@ -169,6 +170,7 @@
       );
     PushOnScopeChains(ClassTypedef, TUScope);
     Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef));
+    Context.ObjCClassRedefinitionType = Context.getObjCClassType();
   }
 }