Introduce the core infrastructure needed to model a complete

redeclaration chain for Objective-C classes, 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 the definition knows that it is the definition.
  - Serialization support for when a definition gets added to a
  declaration that comes from an AST file.

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



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146667 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 39 insertions, 7 deletions

diff --git a/lib/Serialization/ASTCommon.h b/lib/Serialization/ASTCommon.h
index 367f57f715..2e3d70b853 100644
--- a/lib/Serialization/ASTCommon.h
+++ b/lib/Serialization/ASTCommon.h
@@ -26,7 +26,8 @@ enum DeclUpdateKind {
   UPD_CXX_ADDED_IMPLICIT_MEMBER,
   UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION,
   UPD_CXX_ADDED_ANONYMOUS_NAMESPACE,
-  UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER
+  UPD_CXX_INSTANTIATED_STATIC_DATA_MEMBER,
+  UPD_OBJC_SET_CLASS_DEFINITIONDATA
 };
 
 TypeIdx TypeIdxFromBuiltin(const BuiltinType *BT);
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index f7f93af9ce..6fc5764006 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -554,6 +554,7 @@ void ASTDeclReader::VisitObjCContainerDecl(ObjCContainerDecl *CD) {
 }
 
 void ASTDeclReader::VisitObjCInterfaceDecl(ObjCInterfaceDecl *ID) {
+  VisitRedeclarable(ID);
   VisitObjCContainerDecl(ID);
   ID->setTypeForDecl(Reader.readType(F, Record, Idx).getTypePtrOrNull());
   
@@ -618,10 +619,9 @@ void ASTDeclReader::VisitObjCInterfaceDecl(ObjCInterfaceDecl *ID) {
       // pending references were linked.
       Reader.PendingForwardRefs.erase(ID);
 #endif
-    
     } else if (Def) {
-      if (Def->Definition) {
-        ID->Definition = Def->Definition;
+      if (Def->Definition.getPointer()) {
+        ID->Definition.setPointer(Def->Definition.getPointer());
       } else {
         // The definition is still initializing.
         Reader.PendingForwardRefs[Def].push_back(ID);
@@ -2067,6 +2067,19 @@ void ASTDeclReader::UpdateDecl(Decl *D, ModuleFile &ModuleFile,
       cast<VarDecl>(D)->getMemberSpecializationInfo()->setPointOfInstantiation(
           Reader.ReadSourceLocation(ModuleFile, Record, Idx));
       break;
+    
+    case UPD_OBJC_SET_CLASS_DEFINITIONDATA: {
+      ObjCInterfaceDecl *ID = cast<ObjCInterfaceDecl>(D);
+      ObjCInterfaceDecl *Def
+        = Reader.ReadDeclAs<ObjCInterfaceDecl>(ModuleFile, Record, Idx);
+      if (Def->Definition.getPointer()) {
+        ID->Definition.setPointer(Def->Definition.getPointer());
+      } else {
+        // The definition is still initializing.
+        Reader.PendingForwardRefs[Def].push_back(ID);
+      }
+      break;
+    }
     }
   }
 }
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index 6cce0afc50..b3f76f7494 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -3439,6 +3439,7 @@ void ASTWriter::ResolveDeclUpdatesBlocks() {
       case UPD_CXX_ADDED_IMPLICIT_MEMBER:
       case UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION:
       case UPD_CXX_ADDED_ANONYMOUS_NAMESPACE:
+      case UPD_OBJC_SET_CLASS_DEFINITIONDATA:
         URec[Idx] = GetDeclRef(reinterpret_cast<Decl *>(URec[Idx]));
         ++Idx;
         break;
@@ -4379,10 +4380,26 @@ void ASTWriter::AddedObjCCategoryToInterface(const ObjCCategoryDecl *CatD,
 
 void ASTWriter::CompletedObjCForwardRef(const ObjCContainerDecl *D) {
   assert(!WritingAST && "Already writing the AST!");
-  if (!D->isFromASTFile())
-    return; // Declaration not imported from PCH.
+  if (D->isFromASTFile())
+    RewriteDecl(D);
 
-  RewriteDecl(D);
+  if (const ObjCInterfaceDecl *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
+    for (ObjCInterfaceDecl::redecl_iterator I = ID->redecls_begin(), 
+                                            E = ID->redecls_end(); 
+         I != E; ++I) {
+      if (*I == ID)
+        continue;
+      
+      // We are interested when a PCH decl is modified.
+      if (I->isFromASTFile()) {
+        UpdateRecord &Record = DeclUpdates[*I];
+        Record.push_back(UPD_OBJC_SET_CLASS_DEFINITIONDATA);
+        assert((*I)->hasDefinition());
+        assert((*I)->getDefinition() == D);
+        Record.push_back(reinterpret_cast<uint64_t>(D)); // the DefinitionDecl
+      }
+    }
+  }
 }
 
 void ASTWriter::AddedObjCPropertyInClassExtension(const ObjCPropertyDecl *Prop,
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index 9396958659..e641c101a1 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -447,6 +447,7 @@ void ASTDeclWriter::VisitObjCContainerDecl(ObjCContainerDecl *D) {
 }
 
 void ASTDeclWriter::VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
+  VisitRedeclarable(D);
   VisitObjCContainerDecl(D);
   Writer.AddTypeRef(QualType(D->getTypeForDecl(), 0), Record);