[domain availability] Stop copying attributes from an ObjCMethodDecl to

another

Stop copying domain availability attributes between ObjCMethodDecls,
except when moving them from a method declaration to its implementation.

rdar://160157241

Author: ahatanaka

clang/lib/Sema/SemaDecl.cpp

@@ -3293,7 +3293,7 @@ void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
     Diag(Old->getLocation(), diag::note_previous_declaration);
   }
 
-  if (auto *ND = dyn_cast<NamedDecl>(Old))
+  if (auto *ND = dyn_cast<NamedDecl>(Old); ND && !isa<ObjCMethodDecl>(ND))
     copyFeatureAvailabilityCheck(New, ND, true);
 
   if (!Old->hasAttrs())
@@ -3328,6 +3328,9 @@ void Sema::mergeDeclAttributes(NamedDecl *New, Decl *Old,
     if (isa<UsedAttr>(I) || isa<RetainAttr>(I))
       continue;
 
+    if (isa<ObjCMethodDecl>(Old) && isa<DomainAvailabilityAttr>(I))
+      continue;
+
     if (isa<InferredNoReturnAttr>(I)) {
       if (auto *FD = dyn_cast<FunctionDecl>(New)) {
         if (FD->getTemplateSpecializationKind() == TSK_ExplicitSpecialization)

clang/lib/Sema/SemaDeclObjC.cpp

@@ -364,6 +364,24 @@ HasExplicitOwnershipAttr(Sema &S, ParmVarDecl *Param) {
   return !T.getLocalQualifiers().hasObjCLifetime();
 }
 
+/// Helper function to copy domain availability attributes on methods in the
+/// class interfaces or categories to methods in the implementations.
+static void copyDomainAvailabilityAttr(ObjCMethodDecl *MD, Sema &SemaRef) {
+  ObjCContainerDecl *CD = nullptr;
+
+  if (ObjCCategoryDecl *CatD = MD->getCategory())
+    CD = CatD;
+  else if (ObjCInterfaceDecl *ID = MD->getClassInterface())
+    CD = ID;
+
+  if (!CD)
+    return;
+
+  if (ObjCMethodDecl *IDecl =
+          CD->getMethod(MD->getSelector(), MD->isInstanceMethod()))
+    SemaRef.copyFeatureAvailabilityCheck(MD, IDecl, true);
+}
+
 /// ActOnStartOfObjCMethodDef - This routine sets up parameters; invisible
 /// and user declared, in the method definition's AST.
 void SemaObjC::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
@@ -379,6 +397,8 @@ void SemaObjC::ActOnStartOfObjCMethodDef(Scope *FnBodyScope, Decl *D) {
   if (!MDecl)
     return;
 
+  copyDomainAvailabilityAttr(MDecl, SemaRef);
+
   QualType ResultType = MDecl->getReturnType();
   if (!ResultType->isDependentType() && !ResultType->isVoidType() &&
       !MDecl->isInvalidDecl() &&

clang/test/CodeGenObjC/feature-availability.m

@@ -202,7 +202,7 @@ +(void)unavailable_cm1 __attribute__((availability(domain:feature2, AVAIL)));
 @implementation C3
 -(void)p1_m1 {
 }
--(void)unavailable_p2_m2 {
+-(void)unavailable_p2_m2 __attribute__((availability(domain:feature2, AVAIL))) {
   unavailable_func1();
 }
 +(void)cm0 {

clang/test/SemaObjC/feature-availability.m

@@ -176,3 +176,30 @@ @interface Base6 <P1, P2>
 @end
 
 void foo(id<P1>); // expected-error {{use of 'P1' requires feature 'feature1' to be unavailable}}
+
+@interface Base8
+@property (copy) id x;
+@end
+
+__attribute__((availability(domain:feature1, AVAIL)))
+@interface Derived8 : Base8
+@property (copy) id x;
+@end
+
+@interface Base9
+-(void)m4 __attribute__((availability(domain:feature1, AVAIL)));
+@end
+
+@interface Derived9 : Base9
+-(void)m4;
+@end
+
+@implementation Derived9 : Base9
+-(void)m4 {
+  // Check that this method doesn't inherit the domain availablity attribute
+  // from the base class method.
+  func1(); // expected-error {{use of 'func1' requires feature 'feature1' to be available}}
+
+  [super m4]; // expected-error {{use of 'm4' requires feature 'feature1' to be available}}
+}
+@end