ObjCGNU: Fix empty v3 protocols being emitted two fields short

Summary:
Protocols that were being referenced but could not be fully realized were being emitted without `properties`/`optional_properties`. Since all v3 protocols must be 9 processor words wide, the lack of these fields is catastrophic for the runtime.

As an example, the runtime cannot know [here](https://github.com/gnustep/libobjc2/blob/master/protocol.c#L73) that `properties` and `optional_properties` are invalid.

Reviewers: rjmccall, theraven

Reviewed By: rjmccall, theraven

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D45305

llvm-svn: 329882

1 files changed, 7 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CGObjCGNU.cpp b/clang/lib/CodeGen/CGObjCGNU.cpp
index a6b6c38d5cc..6f4cde569f8 100644
--- a/clang/lib/CodeGen/CGObjCGNU.cpp
+++ b/clang/lib/CodeGen/CGObjCGNU.cpp
@@ -1748,11 +1748,13 @@ CGObjCGNU::GenerateEmptyProtocol(const std::string &ProtocolName) {
           llvm::ConstantInt::get(Int32Ty, ProtocolVersion), IdTy));
 
   Elements.add(MakeConstantString(ProtocolName, ".objc_protocol_name"));
-  Elements.add(ProtocolList);
-  Elements.add(MethodList);
-  Elements.add(MethodList);
-  Elements.add(MethodList);
-  Elements.add(MethodList);
+  Elements.add(ProtocolList); /* .protocol_list */
+  Elements.add(MethodList);   /* .instance_methods */
+  Elements.add(MethodList);   /* .class_methods */
+  Elements.add(MethodList);   /* .optional_instance_methods */
+  Elements.add(MethodList);   /* .optional_class_methods */
+  Elements.add(NULLPtr);      /* .properties */
+  Elements.add(NULLPtr);      /* .optional_properties */
   return Elements.finishAndCreateGlobal(".objc_protocol",
                                         CGM.getPointerAlign());
 }