Move the definition-specific data of ObjCInterfaceDecl into a

separately-allocated DefinitionData structure, which we manage the
same way as CXXRecordDecl::DefinitionData. This prepares the way for
making ObjCInterfaceDecls redeclarable, to more accurately model
forward declarations of Objective-C classes and eliminate the mutation
of ObjCInterfaceDecl that causes us serious trouble in the AST reader.

Note that ObjCInterfaceDecl's accessors are fairly robust against
being applied to forward declarations, because Clang (and Sema in
particular) doesn't perform RequireCompleteType/hasDefinition() checks
everywhere it has to. Each of these overly-robust cases is marked with
a FIXME, which we can tackle over time.




git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146644 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 7 deletions

diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index b70c982955..6947d7e211 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -368,10 +368,10 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
   ObjCInterfaceDecl* IDecl = dyn_cast_or_null<ObjCInterfaceDecl>(PrevDecl);
   if (IDecl) {
     // Class already seen. Is it a forward declaration?
-    if (!IDecl->isForwardDecl()) {
+    if (ObjCInterfaceDecl *Def = IDecl->getDefinition()) {
       IDecl->setInvalidDecl();
       Diag(AtInterfaceLoc, diag::err_duplicate_class_def)<<IDecl->getDeclName();
-      Diag(IDecl->getLocation(), diag::note_previous_definition);
+      Diag(Def->getLocation(), diag::note_previous_definition);
 
       // Create a new one; the other may be in a different DeclContex, (e.g.
       // this one may be in a LinkageSpecDecl while the other is not) which
@@ -392,8 +392,6 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
       IDecl->setLexicalDeclContext(CurContext);
       CurContext->addDecl(IDecl);
 
-      IDecl->completedForwardDecl();
-
       if (AttrList)
         ProcessDeclAttributeList(TUScope, IDecl, AttrList);
     }
@@ -406,6 +404,9 @@ ActOnStartClassInterface(SourceLocation AtInterfaceLoc,
     PushOnScopeChains(IDecl, TUScope);
   }
 
+  if (!IDecl->hasDefinition())
+    IDecl->startDefinition();
+  
   if (SuperName) {
     // Check if a different kind of symbol declared in this scope.
     PrevDecl = LookupSingleName(TUScope, SuperName, SuperLoc,
@@ -942,6 +943,7 @@ Decl *Sema::ActOnStartClassImplementation(
     // copy them over.
     IDecl = ObjCInterfaceDecl::Create(Context, CurContext, AtClassImplLoc,
                                       ClassName, ClassLoc, false, true);
+    IDecl->startDefinition();
     IDecl->setSuperClass(SDecl);
     IDecl->setLocEnd(ClassLoc);
 
@@ -950,8 +952,8 @@ Decl *Sema::ActOnStartClassImplementation(
     // Mark the interface as being completed, even if it was just as
     //   @class ....;
     // declaration; the user cannot reopen it.
-    if (IDecl->isForwardDecl())
-      IDecl->completedForwardDecl();
+    if (!IDecl->hasDefinition())
+      IDecl->startDefinition();
   }
 
   ObjCImplementationDecl* IMPDecl =
@@ -2540,7 +2542,9 @@ private:
 
   void searchFrom(ObjCInterfaceDecl *iface) {
     // A method in a class declaration overrides declarations from
-
+    if (!iface->hasDefinition())
+      return;
+    
     //   - categories,
     for (ObjCCategoryDecl *category = iface->getCategoryList();
            category; category = category->getNextClassCategory())