Substantially alter the design of the Objective C type AST by introducing
ObjCObjectType, which is basically just a pair of
  one of {primitive-id, primitive-Class, user-defined @class}
with
  a list of protocols.
An ObjCObjectPointerType is therefore just a pointer which always points to
one of these types (possibly sugared).  ObjCInterfaceType is now just a kind
of ObjCObjectType which happens to not carry any protocols.

Alter a rather large number of use sites to use ObjCObjectType instead of
ObjCInterfaceType.  Store an ObjCInterfaceType as a pointer on the decl rather
than hashing them in a FoldingSet.  Remove some number of methods that are no
longer used, at least after this patch.

By simplifying ObjCObjectPointerType, we are now able to easily remove and apply
pointers to Objective-C types, which is crucial for a certain kind of ObjC++
metaprogramming common in WebKit.

llvm-svn: 103870
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index d904907..3200288 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -30,7 +30,7 @@
 Sema::OwningStmtResult Sema::ActOnExprStmt(FullExprArg expr) {
   Expr *E = expr->takeAs<Expr>();
   assert(E && "ActOnExprStmt(): missing expression");
-  if (E->getType()->isObjCInterfaceType()) {
+  if (E->getType()->isObjCObjectType()) {
     if (LangOpts.ObjCNonFragileABI)
       Diag(E->getLocEnd(), diag::err_indirection_requires_nonfragile_object)
              << E->getType();