[Sema] Delay checking whether objc_designated_initializer is being applied to an init method

This fixes a regression that was caused by r335084, which reversed
the order that attributes are applied. objc_method_family can change
whether a method is an init method, so the order that these
attributes are applied matters. The commit fixes this by delaying the
init check until after all attributes have been applied.

rdar://47829358

Differential revision: https://reviews.llvm.org/D58152

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@353976 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/Attr.td

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index 015d5f7..849d2c2 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -102,13 +102,6 @@
                                        [{S->isInstanceMethod()}],
                                        "Objective-C instance methods">;
 
-def ObjCInterfaceDeclInitMethod : SubsetSubject<ObjCMethod,
-                               [{S->getMethodFamily() == OMF_init &&
-                                 (isa<ObjCInterfaceDecl>(S->getDeclContext()) ||
-                                  (isa<ObjCCategoryDecl>(S->getDeclContext()) &&
-            cast<ObjCCategoryDecl>(S->getDeclContext())->IsClassExtension()))}],
-            "init methods of interface or class extension declarations">;
-
 def Struct : SubsetSubject<Record,
                            [{!S->isUnion()}], "structs">;
 
@@ -1786,7 +1779,7 @@
 
 def ObjCDesignatedInitializer : Attr {
   let Spellings = [Clang<"objc_designated_initializer">];
-  let Subjects = SubjectList<[ObjCInterfaceDeclInitMethod], ErrorDiag>;
+  let Subjects = SubjectList<[ObjCMethod], ErrorDiag>;
   let Documentation = [Undocumented];
 }
 

include/clang/Basic/DiagnosticSemaKinds.td

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 71f205d..c01b0a5 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3481,6 +3481,9 @@
 def warn_objc_implementation_missing_designated_init_override : Warning<
   "method override for the designated initializer of the superclass %objcinstance0 not found">,
   InGroup<ObjCDesignatedInit>;
+def err_designated_init_attr_non_init : Error<
+  "'objc_designated_initializer' attribute only applies to init methods "
+  "of interface or class extension declarations">;
 
 // objc_bridge attribute diagnostics.
 def err_objc_attr_not_id : Error<

lib/Sema/SemaDeclAttr.cpp

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 859ef80..1440b6c 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -5249,11 +5249,22 @@
 
 static void handleObjCDesignatedInitializer(Sema &S, Decl *D,
                                             const ParsedAttr &AL) {
+  DeclContext *Ctx = D->getDeclContext();
+
+  // This attribute can only be applied to methods in interfaces or class
+  // extensions.
+  if (!isa<ObjCInterfaceDecl>(Ctx) &&
+      !(isa<ObjCCategoryDecl>(Ctx) &&
+        cast<ObjCCategoryDecl>(Ctx)->IsClassExtension())) {
+    S.Diag(D->getLocation(), diag::err_designated_init_attr_non_init);
+    return;
+  }
+
   ObjCInterfaceDecl *IFace;
-  if (auto *CatDecl = dyn_cast<ObjCCategoryDecl>(D->getDeclContext()))
+  if (auto *CatDecl = dyn_cast<ObjCCategoryDecl>(Ctx))
     IFace = CatDecl->getClassInterface();
   else
-    IFace = cast<ObjCInterfaceDecl>(D->getDeclContext());
+    IFace = cast<ObjCInterfaceDecl>(Ctx);
 
   if (!IFace)
     return;
@@ -7243,6 +7254,17 @@
       }
     }
   }
+
+  // Do this check after processing D's attributes because the attribute
+  // objc_method_family can change whether the given method is in the init
+  // family, and it can be applied after objc_designated_initializer. This is a
+  // bit of a hack, but we need it to be compatible with versions of clang that
+  // processed the attribute list in the wrong order.
+  if (D->hasAttr<ObjCDesignatedInitializerAttr>() &&
+      cast<ObjCMethodDecl>(D)->getMethodFamily() != OMF_init) {
+    Diag(D->getLocation(), diag::err_designated_init_attr_non_init);
+    D->dropAttr<ObjCDesignatedInitializerAttr>();
+  }
 }
 
 // Helper for delayed processing TransparentUnion attribute.

test/Misc/pragma-attribute-supported-attributes-list.test

diff --git a/test/Misc/pragma-attribute-supported-attributes-list.test b/test/Misc/pragma-attribute-supported-attributes-list.test
index 22ad3ac..45012ae 100644
--- a/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -97,6 +97,7 @@
 // CHECK-NEXT: ObjCBridge (SubjectMatchRule_record, SubjectMatchRule_type_alias)
 // CHECK-NEXT: ObjCBridgeMutable (SubjectMatchRule_record)
 // CHECK-NEXT: ObjCBridgeRelated (SubjectMatchRule_record)
+// CHECK-NEXT: ObjCDesignatedInitializer (SubjectMatchRule_objc_method)
 // CHECK-NEXT: ObjCException (SubjectMatchRule_objc_interface)
 // CHECK-NEXT: ObjCExplicitProtocolImpl (SubjectMatchRule_objc_protocol)
 // CHECK-NEXT: ObjCExternallyRetained (SubjectMatchRule_variable_not_is_parameter, SubjectMatchRule_function, SubjectMatchRule_block, SubjectMatchRule_objc_method)

test/SemaObjC/attr-designated-init.m

diff --git a/test/SemaObjC/attr-designated-init.m b/test/SemaObjC/attr-designated-init.m
index 0508588..3558916 100644
--- a/test/SemaObjC/attr-designated-init.m
+++ b/test/SemaObjC/attr-designated-init.m
@@ -3,7 +3,7 @@
 #define NS_DESIGNATED_INITIALIZER __attribute__((objc_designated_initializer))
 #define NS_UNAVAILABLE __attribute__((unavailable))
 
-void fnfoo(void) NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to init methods of interface or class extension declarations}}
+void fnfoo(void) NS_DESIGNATED_INITIALIZER; // expected-error {{'objc_designated_initializer' attribute only applies to Objective-C methods}}
 
 @protocol P1
 -(id)init NS_DESIGNATED_INITIALIZER; // expected-error {{only applies to init methods of interface or class extension declarations}}
@@ -428,3 +428,16 @@
 @interface CategoryForMissingInterface(Cat) // expected-error{{cannot find interface declaration}}
 - (instancetype)init NS_DESIGNATED_INITIALIZER; // expected-error{{only applies to init methods of interface or class extension declarations}}
 @end
+
+@interface TwoAttrs
+-(instancetype)foo
+    __attribute__((objc_designated_initializer))
+    __attribute__((objc_method_family(init)));
+-(instancetype)bar
+    __attribute__((objc_method_family(init)))
+    __attribute__((objc_designated_initializer));
+-(instancetype)baz
+  __attribute__((objc_designated_initializer, objc_method_family(init)));
+-(instancetype)quux
+  __attribute__((objc_method_family(init), objc_designated_initializer));
+@end