r196314 - [objc] Introduce attribute 'objc_designated_initializer'.

[Aaron Ballman]

On Tue, Dec 3, 2013 at 4:11 PM, Argyrios Kyrtzidis <akyrtzi at gmail.com> wrote:
> Author: akirtzidis
> Date: Tue Dec  3 15:11:25 2013
> New Revision: 196314
>
> URL: http://llvm.org/viewvc/llvm-project?rev=196314&view=rev
> Log:
> [objc] Introduce attribute 'objc_designated_initializer'.
>
> It only applies to methods of init family in an interface declaration.
>
> Added:
>     cfe/trunk/test/SemaObjC/attr-designated-init.m
> Modified:
>     cfe/trunk/include/clang/Basic/Attr.td
>     cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>     cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>
> Modified: cfe/trunk/include/clang/Basic/Attr.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=196314&r1=196313&r2=196314&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/Attr.td (original)
> +++ cfe/trunk/include/clang/Basic/Attr.td Tue Dec  3 15:11:25 2013
> @@ -684,6 +684,11 @@ def ObjCSuppressProtocol : InheritableAt
>    let Args = [IdentifierArgument<"Protocol">];
>  }
>
> +def ObjCDesignatedInitializer : Attr {
> +  let Spellings = [GNU<"objc_designated_initializer">];
> +  let Subjects = SubjectList<[ObjCMethod], ErrorDiag>;

Considering how simple the semantic checks are, I think a
SubsetSubject is more appropriate.  Something like:

def ObjCInitFamily : SubsetSubject<ObjCMethod, [{S->getMethodFamily()
== OMF_init}]>;

def ObjCInterfaceDeclContext : SubsetSubject<ObjCMethod,
[{isa<ObjCInterfaceDecl>(S->getDeclContext())}]>;

> +}
> +
>  def Overloadable : Attr {
>    let Spellings = [GNU<"overloadable">];
>    let Subjects = SubjectList<[Function], ErrorDiag>;
>
> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=196314&r1=196313&r2=196314&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Dec  3 15:11:25 2013
> @@ -2427,6 +2427,12 @@ def warn_objc_requires_super_protocol :
>  def note_protocol_decl : Note<
>    "protocol is declared here">;
>
> +// objc_designated_initializer attribute diagnostics.
> +def err_attr_objc_designated_not_init_family : Error<
> +  "'objc_designated_initializer' only applies to methods of the init family">;
> +def err_attr_objc_designated_not_interface : Error<
> +  "'objc_designated_initializer' only applies to methods of interface declarations">;

Both of these should be attached to the existing diagnostics applying
to attribute subjects (warn_attribute_wrong_decl_type and
err_attribute_wrong_decl_type). When switching over to the subset
subjects, you need to supply a custom error diagnostic argument
anyway. Don't forget to update AttributeList.h with the new enumerant.

> +
>  def err_ns_bridged_not_interface : Error<
>    "parameter of 'ns_bridged' attribute does not name an Objective-C class">;
>
>
> Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=196314&r1=196313&r2=196314&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Tue Dec  3 15:11:25 2013
> @@ -3713,6 +3713,28 @@ static void handleObjCBridgeMutableAttr(
>                              Attr.getAttributeSpellingListIndex()));
>  }
>
> +static void handleObjCDesignatedInitializer(Sema &S, Decl *D,
> +                                            const AttributeList &Attr) {
> +  SourceLocation Loc = Attr.getLoc();
> +  ObjCMethodDecl *Method = cast<ObjCMethodDecl>(D);
> +
> +  if (Method->getMethodFamily() != OMF_init) {
> +    S.Diag(D->getLocStart(), diag::err_attr_objc_designated_not_init_family)
> +    << SourceRange(Loc, Loc);
> +    return;
> +  }
> +  DeclContext *DC = Method->getDeclContext();
> +  if (!isa<ObjCInterfaceDecl>(DC)) {
> +    S.Diag(D->getLocStart(), diag::err_attr_objc_designated_not_interface)
> +    << SourceRange(Loc, Loc);
> +    return;
> +  }
> +
> +  Method->addAttr(::new (S.Context)
> +                  ObjCDesignatedInitializerAttr(Attr.getRange(), S.Context,
> +                                         Attr.getAttributeSpellingListIndex()));

Once you use the SubsetSubjects, this entire method can go away.

> +}
> +
>  static void handleObjCOwnershipAttr(Sema &S, Decl *D,
>                                      const AttributeList &Attr) {
>    if (hasDeclarator(D)) return;
> @@ -3963,6 +3985,9 @@ static void ProcessDeclAttribute(Sema &S
>    case AttributeList::AT_ObjCBridgeMutable:
>      handleObjCBridgeMutableAttr(S, scope, D, Attr); break;
>
> +  case AttributeList::AT_ObjCDesignatedInitializer:
> +    handleObjCDesignatedInitializer(S, D, Attr); break;

Once the handler method goes away, this can be replaced with:

handleSimpleAttribute<ObjCDesignatedInitializerAttr>(S, D, Attr); break;

> +
>    case AttributeList::AT_CFAuditedTransfer:
>      handleCFAuditedTransferAttr(S, D, Attr); break;
>    case AttributeList::AT_CFUnknownTransfer:
>
> Added: cfe/trunk/test/SemaObjC/attr-designated-init.m
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/attr-designated-init.m?rev=196314&view=auto
> ==============================================================================
> --- cfe/trunk/test/SemaObjC/attr-designated-init.m (added)
> +++ cfe/trunk/test/SemaObjC/attr-designated-init.m Tue Dec  3 15:11:25 2013
> @@ -0,0 +1,32 @@
> +// RUN: %clang_cc1 -fsyntax-only -verify %s
> +
> +#define NS_DESIGNATED_INITIALIZER __attribute__((objc_designated_initializer))
> +
> +void fnfoo(void) NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods}}
> +
> + at protocol P1
> +-(id)init NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
> + at end
> +
> +__attribute__((objc_root_class))
> + at interface I1
> +-(void)meth NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of the init family}}
> +-(id)init NS_DESIGNATED_INITIALIZER;
> ++(id)init NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of the init family}}
> + at end
> +
> + at interface I1(cat)
> +-(id)init2 NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
> + at end
> +
> + at interface I1()
> +-(id)init3 NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
> + at end
> +
> + at implementation I1
> +-(void)meth {}
> +-(id)init NS_DESIGNATED_INITIALIZER { return 0; } // expected-error {{only applies to methods of interface declarations}}
> ++(id)init { return 0; }
> +-(id)init3 { return 0; }
> +-(id)init4 NS_DESIGNATED_INITIALIZER { return 0; } // expected-error {{only applies to methods of interface declarations}}
> + at end

~Aaron