From 31d5d5d6f0cabd6a8260e743679e28cdbd4a912b Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Tue, 3 Dec 2013 21:11:25 +0000
Subject: [PATCH] [objc] Introduce attribute 'objc_designated_initializer'.

It only applies to methods of init family in an interface declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196314 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/Attr.td                |  5 ++++
 include/clang/Basic/DiagnosticSemaKinds.td |  6 ++++
 lib/Sema/SemaDeclAttr.cpp                  | 25 +++++++++++++++++
 test/SemaObjC/attr-designated-init.m       | 32 ++++++++++++++++++++++
 4 files changed, 68 insertions(+)
 create mode 100644 test/SemaObjC/attr-designated-init.m

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index df8c4edc2c..2268fa6478 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -684,6 +684,11 @@ def ObjCSuppressProtocol : InheritableAttr {
   let Args = [IdentifierArgument<"Protocol">];
 }
 
+def ObjCDesignatedInitializer : Attr {
+  let Spellings = [GNU<"objc_designated_initializer">];
+  let Subjects = SubjectList<[ObjCMethod], ErrorDiag>;
+}
+
 def Overloadable : Attr {
   let Spellings = [GNU<"overloadable">];
   let Subjects = SubjectList<[Function], ErrorDiag>;
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index a22df2b1af..8315c78f25 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2427,6 +2427,12 @@ def warn_objc_requires_super_protocol : Warning<
 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">;
+
 def err_ns_bridged_not_interface : Error<
   "parameter of 'ns_bridged' attribute does not name an Objective-C class">;
   
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 24f9f5fd25..b732fccacf 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -3713,6 +3713,28 @@ static void handleObjCBridgeMutableAttr(Sema &S, Scope *Sc, Decl *D,
                             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()));
+}
+
 static void handleObjCOwnershipAttr(Sema &S, Decl *D,
                                     const AttributeList &Attr) {
   if (hasDeclarator(D)) return;
@@ -3963,6 +3985,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_ObjCBridgeMutable:
     handleObjCBridgeMutableAttr(S, scope, D, Attr); break;
 
+  case AttributeList::AT_ObjCDesignatedInitializer:
+    handleObjCDesignatedInitializer(S, D, Attr); break;
+
   case AttributeList::AT_CFAuditedTransfer:
     handleCFAuditedTransferAttr(S, D, Attr); break;
   case AttributeList::AT_CFUnknownTransfer:
diff --git a/test/SemaObjC/attr-designated-init.m b/test/SemaObjC/attr-designated-init.m
new file mode 100644
index 0000000000..f607bb6944
--- /dev/null
+++ b/test/SemaObjC/attr-designated-init.m
@@ -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}}
+
+@protocol P1
+-(id)init NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
+@end
+
+__attribute__((objc_root_class))
+@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}}
+@end
+
+@interface I1(cat)
+-(id)init2 NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
+@end
+
+@interface I1()
+-(id)init3 NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to methods of interface declarations}}
+@end
+
+@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}}
+@end
-- 
2.40.0