[PCH] When completing an objc forward reference, do not serialize the chain of its categories because

it is going to be rewritten (and the chain will be serialized again), otherwise we may form a cycle in its
categories list when deserializing.

Also introduce ASTMutationListener::CompletedObjCForwardRef to notify that a forward reference
was completed; using Decl's isChangedSinceDeserialization/setChangedSinceDeserialization
is bug inducing and kinda gross, we should phase it out.

Fixes infinite loop in rdar://10418538.

llvm-svn: 144465

1 files changed, 6 insertions, 10 deletions

diff --git a/clang/lib/Sema/SemaDeclObjC.cpp b/clang/lib/Sema/SemaDeclObjC.cpp
index 1632e092e3b..3d1f5bd0640 100644
--- a/clang/lib/Sema/SemaDeclObjC.cpp
+++ b/clang/lib/Sema/SemaDeclObjC.cpp
@@ -377,18 +377,16 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
       return ActOnObjCContainerStartDefinition(IDecl);
     } else {
       IDecl->setLocation(ClassLoc);
-      IDecl->setForwardDecl(false);
       IDecl->setAtStartLoc(AtInterfaceLoc);
-      // If the forward decl was in a PCH, we need to write it again in a
-      // dependent AST file.
-      IDecl->setChangedSinceDeserialization(true);
       
       // Since this ObjCInterfaceDecl was created by a forward declaration,
       // we now add it to the DeclContext since it wasn't added before
       // (see ActOnForwardClassDeclaration).
       IDecl->setLexicalDeclContext(CurContext);
       CurContext->addDecl(IDecl);
-      
+
+      IDecl->completedForwardDecl();
+
       if (AttrList)
         ProcessDeclAttributeList(TUScope, IDecl, AttrList);
     }
@@ -588,19 +586,16 @@ Sema::ActOnStartProtocolInterface(SourceLocation AtProtoInterfaceLoc,
     // Make sure the cached decl gets a valid start location.
     PDecl->setAtStartLoc(AtProtoInterfaceLoc);
     PDecl->setLocation(ProtocolLoc);
-    PDecl->setForwardDecl(false);
     // Since this ObjCProtocolDecl was created by a forward declaration,
     // we now add it to the DeclContext since it wasn't added before
     PDecl->setLexicalDeclContext(CurContext);
     CurContext->addDecl(PDecl);
-    // Repeat in dependent AST files.
-    PDecl->setChangedSinceDeserialization(true);
+    PDecl->completedForwardDecl();
   } else {
     PDecl = ObjCProtocolDecl::Create(Context, CurContext, ProtocolName,
                                      ProtocolLoc, AtProtoInterfaceLoc,
                                      /*isForwardDecl=*/false);
     PushOnScopeChains(PDecl, TUScope);
-    PDecl->setForwardDecl(false);
   }
   if (AttrList)
     ProcessDeclAttributeList(TUScope, PDecl, AttrList);
@@ -925,7 +920,8 @@ Decl *Sema::ActOnStartClassImplementation(
     // Mark the interface as being completed, even if it was just as
     //   @class ....;
     // declaration; the user cannot reopen it.
-    IDecl->setForwardDecl(false);
+    if (IDecl->isForwardDecl())
+      IDecl->completedForwardDecl();
   }
 
   ObjCImplementationDecl* IMPDecl =