[CodeGen][ObjC] Include all referenced protocols in protocol list (#148827)

When constructing the protocol list in the class metadata generation
(`GenerateClass`), only the protocols from the base class are added but
not protocols declared in class extensions.

This is fixed by using `all_referenced_protocol_{begin, end}` instead of
`protocol_{begin, end}`, matching the behaviour on Apple platforms.

A unit test is included to check if all protocol metadata was emitted
and that no duplication occurs in the protocol list.

Fixes https://github.com/gnustep/libobjc2/issues/339

CC: @davidchisnall

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGObjCGNU.cpp b/clang/lib/CodeGen/CGObjCGNU.cpp
index d828702..8acf8d2 100644
--- a/clang/lib/CodeGen/CGObjCGNU.cpp
+++ b/clang/lib/CodeGen/CGObjCGNU.cpp
@@ -1942,8 +1942,9 @@ class CGObjCGNUstep2 : public CGObjCGNUstep {
     // struct objc_class *sibling_class
     classFields.addNullPointer(PtrTy);
     // struct objc_protocol_list *protocols;
-    auto RuntimeProtocols = GetRuntimeProtocolList(classDecl->protocol_begin(),
-                                                   classDecl->protocol_end());
+    auto RuntimeProtocols =
+        GetRuntimeProtocolList(classDecl->all_referenced_protocol_begin(),
+                               classDecl->all_referenced_protocol_end());
     SmallVector<llvm::Constant *, 16> Protocols;
     for (const auto *I : RuntimeProtocols)
       Protocols.push_back(GenerateProtocolRef(I));