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, 5 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGObjCGNU.cpp b/clang/lib/CodeGen/CGObjCGNU.cpp
index 0a207ab76d5..3a591e88ddb 100644
--- a/clang/lib/CodeGen/CGObjCGNU.cpp
+++ b/clang/lib/CodeGen/CGObjCGNU.cpp
@@ -1529,6 +1529,11 @@ llvm::Constant *CGObjCGNU::GenerateEmptyProtocol(
 void CGObjCGNU::GenerateProtocol(const ObjCProtocolDecl *PD) {
   ASTContext &Context = CGM.getContext();
   std::string ProtocolName = PD->getNameAsString();
+  
+  // Use the protocol definition, if there is one.
+  if (const ObjCProtocolDecl *Def = PD->getDefinition())
+    PD = Def;
+
   SmallVector<std::string, 16> Protocols;
   for (ObjCProtocolDecl::protocol_iterator PI = PD->protocol_begin(),
        E = PD->protocol_end(); PI != E; ++PI)