Rework the traversal of Objective-C categories and extensions to

consider (sub)module visibility.

The bulk of this change replaces myriad hand-rolled loops over the
linked list of Objective-C categories/extensions attached to an
interface declaration with loops using one of the four new category
iterator kinds:

  visible_categories_iterator: Iterates over all visible categories
  and extensions, hiding any that have their "hidden" bit set. This is
  by far the most commonly used iterator.

  known_categories_iterator: Iterates over all categories and
  extensions, ignoring the "hidden" bit. This tends to be used for
  redeclaration-like traversals.

  visible_extensions_iterator: Iterates over all visible extensions,
  hiding any that have their "hidden" bit set.

  known_extensions_iterator: Iterates over all extensions, whether
  they are visible to normal name lookup or not.

The effect of this change is that any uses of the visible_ iterators
will respect module-import visibility. See the new tests for examples.

Note that the old accessors for categories and extensions are gone;
there are *Raw() forms for some of them, for those (few) areas of the
compiler that have to manipulate the linked list of categories
directly. This is generally discouraged.

Part two of <rdar://problem/10634711>.
 

llvm-svn: 172665

1 files changed, 6 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 5d655e24c06..994b2126132 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -10472,11 +10472,12 @@ void Sema::ActOnFields(Scope* S,
             Diag(ClsIvar->getLocation(), diag::note_previous_definition);
             continue;
           }
-          for (const ObjCCategoryDecl *ClsExtDecl = 
-                IDecl->getFirstClassExtension();
-               ClsExtDecl; ClsExtDecl = ClsExtDecl->getNextClassExtension()) {
-            if (const ObjCIvarDecl *ClsExtIvar = 
-                ClsExtDecl->getIvarDecl(ClsFields[i]->getIdentifier())) {
+          for (ObjCInterfaceDecl::known_extensions_iterator
+                 Ext = IDecl->known_extensions_begin(),
+                 ExtEnd = IDecl->known_extensions_end();
+               Ext != ExtEnd; ++Ext) {
+            if (const ObjCIvarDecl *ClsExtIvar
+                  = Ext->getIvarDecl(ClsFields[i]->getIdentifier())) {
               Diag(ClsFields[i]->getLocation(), 
                    diag::err_duplicate_ivar_declaration); 
               Diag(ClsExtIvar->getLocation(), diag::note_previous_definition);