Rename CGT::VerifyFuncTypeComplete to isFuncTypeConvertible since

it is a predicate, not an action.  Change the return type to be a bool,
not the incomplete member.  Enhace it to detect the recursive compilation
case, allowing us to compile Eli's testcase on llvmdev:

struct T {
 struct T (*p)(void);
} t;

into:

%struct.T = type { {}* }

@t = common global %struct.T zeroinitializer, align 8

llvm-svn: 134853

clang/lib/CodeGen/CGVTables.cpp

@@ -2937,7 +2937,8 @@ void CodeGenVTables::MaybeEmitThunkAvailableExternally(GlobalDecl GD,
 
   // We can't emit thunks for member functions with incomplete types.
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
-  if (CGM.getTypes().VerifyFuncTypeComplete(MD->getType().getTypePtr()))
+  if (!CGM.getTypes().isFuncTypeConvertible(
+                                cast<FunctionType>(MD->getType().getTypePtr())))
     return;
 
   EmitThunk(GD, Thunk, /*UseAvailableExternallyLinkage=*/true);