arphaman updated this revision to Diff 76019.
arphaman marked 3 inline comments as done.
arphaman added a comment.
The updated patch adds documentation and modifies the diagnostic message.
Repository:
rL LLVM
https://reviews.llvm.org/D25993
Files:
include/clang/Basic/Attr.td
include/clang/Basic/AttrDocs.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaDeclAttr.cpp
lib/Sema/SemaDeclObjC.cpp
test/SemaObjC/subclassing-restricted-attr.m
Index: test/SemaObjC/subclassing-restricted-attr.m
===================================================================
--- /dev/null
+++ test/SemaObjC/subclassing-restricted-attr.m
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -x objective-c++ -fsyntax-only -verify -Wno-objc-root-class %s
+// rdar://16560476
+
+__attribute__((objc_subclassing_restricted))
+@interface Leaf // okay
+@end
+
+__attribute__((objc_subclassing_restricted))
+@interface SubClassOfLeaf : Leaf // expected-note {{class is declared here}}
+@end
+
+
+@interface SubClass : SubClassOfLeaf // expected-error {{cannot subclass a class that was declared with the 'objc_subclassing_restricted' attribute}}
+@end
+
+__attribute__((objc_root_class))
+@interface PlainRoot
+@end
+
+__attribute__((objc_subclassing_restricted))
+@interface Sub2Class : PlainRoot // okay
+@end
+
+// rdar://28753587
+__attribute__((objc_subclassing_restricted))
+@interface SuperImplClass // expected-note {{class is declared here}}
+@end
+@implementation SuperImplClass
+@end
+
+__attribute__((objc_subclassing_restricted))
+@interface SubImplClass : SuperImplClass
+@end
+@implementation SubImplClass // expected-error {{cannot subclass a class that was declared with the 'objc_subclassing_restricted' attribute}}
+@end
Index: lib/Sema/SemaDeclObjC.cpp
===================================================================
--- lib/Sema/SemaDeclObjC.cpp
+++ lib/Sema/SemaDeclObjC.cpp
@@ -3853,6 +3853,18 @@
Diag(IDecl->getLocation(), diag::err_objc_root_class_subclass);
}
+ if (const ObjCInterfaceDecl *Super = IDecl->getSuperClass()) {
+ // An interface can subclass another interface with a
+ // objc_subclassing_restricted attribute when it has that attribute as
+ // well (because of interfaces imported from Swift). Therefore we have
+ // to check if we can subclass in the implementation as well.
+ if (IDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
+ Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
+ Diag(IC->getLocation(), diag::err_restricted_superclass_mismatch);
+ Diag(Super->getLocation(), diag::note_class_declared);
+ }
+ }
+
if (LangOpts.ObjCRuntime.isNonFragile()) {
while (IDecl->getSuperClass()) {
DiagnoseDuplicateIvars(IDecl, IDecl->getSuperClass());
@@ -3873,6 +3885,14 @@
ImplMethodsVsClassMethods(S, CatImplClass, Cat);
}
}
+ } else if (const auto *IntfDecl = dyn_cast<ObjCInterfaceDecl>(ClassDecl)) {
+ if (const ObjCInterfaceDecl *Super = IntfDecl->getSuperClass()) {
+ if (!IntfDecl->hasAttr<ObjCSubclassingRestrictedAttr>() &&
+ Super->hasAttr<ObjCSubclassingRestrictedAttr>()) {
+ Diag(IntfDecl->getLocation(), diag::err_restricted_superclass_mismatch);
+ Diag(Super->getLocation(), diag::note_class_declared);
+ }
+ }
}
if (isInterfaceDeclKind) {
// Reject invalid vardecls.
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -5776,6 +5776,9 @@
case AttributeList::AT_ObjCRootClass:
handleSimpleAttribute<ObjCRootClassAttr>(S, D, Attr);
break;
+ case AttributeList::AT_ObjCSubclassingRestricted:
+ handleSimpleAttribute<ObjCSubclassingRestrictedAttr>(S, D, Attr);
+ break;
case AttributeList::AT_ObjCExplicitProtocolImpl:
handleObjCSuppresProtocolAttr(S, D, Attr);
break;
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -781,6 +781,9 @@
"class with specified objc_requires_property_definitions attribute is declared here">;
def err_objc_root_class_subclass : Error<
"objc_root_class attribute may only be specified on a root class declaration">;
+def err_restricted_superclass_mismatch : Error<
+ "cannot subclass a class that was declared with the "
+ "'objc_subclassing_restricted' attribute">;
def warn_objc_root_class_missing : Warning<
"class %0 defined without specifying a base class">,
InGroup<ObjCRootClass>;
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -2649,3 +2649,11 @@
If a function has neither of these attributes, they become subject to the XRay heuristics used to determine whether a function should be instrumented or otherwise.
}];
}
+
+def ObjCSubclassingRestrictedDocs : Documentation {
+ let Category = DocCatType;
+ let Content = [{
+This attribute can be added to an Objective-C ``@interface`` declaration to
+ensure that this class cannot be subclassed.
+ }];
+}
Index: include/clang/Basic/Attr.td
===================================================================
--- include/clang/Basic/Attr.td
+++ include/clang/Basic/Attr.td
@@ -1285,6 +1285,12 @@
let Documentation = [Undocumented];
}
+def ObjCSubclassingRestricted : InheritableAttr {
+ let Spellings = [GNU<"objc_subclassing_restricted">];
+ let Subjects = SubjectList<[ObjCInterface], ErrorDiag>;
+ let Documentation = [ObjCSubclassingRestrictedDocs];
+}
+
def ObjCExplicitProtocolImpl : InheritableAttr {
let Spellings = [GNU<"objc_protocol_requires_explicit_implementation">];
let Subjects = SubjectList<[ObjCProtocol], ErrorDiag>;
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