Introduce the core infrastructure needed to model redeclaration chains

for Objective-C protocols, including:
  - Using the first declaration as the canonical declaration
  - Using the definition as the primary DeclContext
  - Making sure that all declarations have a pointer to the definition
  data, and that we know which declaration is the definition
  - Serialization support for redeclaration chains and for adding
  definitions to already-serialized declarations.

However, note that we're not taking advantage of much of this code
yet, because we're still re-using ObjCProtocolDecls.

llvm-svn: 147410

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 121395676fd..a782db76f68 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -1787,6 +1787,10 @@ llvm::Constant *CGObjCMac::GetOrEmitProtocol(const ObjCProtocolDecl *PD) {
   if (Entry && Entry->hasInitializer())
     return Entry;
 
+  // Use the protocol definition, if there is one.
+  if (const ObjCProtocolDecl *Def = PD->getDefinition())
+    PD = Def;
+
   // FIXME: I don't understand why gcc generates this, or where it is
   // resolved. Investigate. Its also wasteful to look this up over and over.
   LazySymbols.insert(&CGM.getContext().Idents.get("Protocol"));
@@ -5413,6 +5417,10 @@ llvm::Constant *CGObjCNonFragileABIMac::GetOrEmitProtocol(
   if (Entry && Entry->hasInitializer())
     return Entry;
 
+  // Use the protocol definition, if there is one.
+  if (const ObjCProtocolDecl *Def = PD->getDefinition())
+    PD = Def;
+  
   // Construct method lists.
   std::vector<llvm::Constant*> InstanceMethods, ClassMethods;
   std::vector<llvm::Constant*> OptInstanceMethods, OptClassMethods;