[ObjC] Avoid the -Wunguarded-availability warnings for protocol

requirements in protocol/class/category declarations

The unguarded availability warnings in the protocol requirements of a protocol
/class/category declaration can be avoided. This matches the behaviour of
Swift's diagnostics. The warnings for deprecated/unavailable protocols are
preserved.

rdar://33156429

Differential Revision: https://reviews.llvm.org/D35061

llvm-svn: 307368

clang/include/clang/Sema/Sema.h

@@ -3900,8 +3900,9 @@ public:
 
   bool CanUseDecl(NamedDecl *D, bool TreatUnavailableAsInvalid);
   bool DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
-                         const ObjCInterfaceDecl *UnknownObjCClass=nullptr,
-                         bool ObjCPropertyAccess=false);
+                         const ObjCInterfaceDecl *UnknownObjCClass = nullptr,
+                         bool ObjCPropertyAccess = false,
+                         bool AvoidPartialAvailabilityChecks = false);
   void NoteDeletedFunction(FunctionDecl *FD);
   void NoteDeletedInheritingConstructor(CXXConstructorDecl *CD);
   std::string getDeletedOrUnavailableSuffix(const FunctionDecl *FD);

clang/lib/Sema/SemaDeclObjC.cpp

@@ -458,7 +458,10 @@ static void diagnoseUseOfProtocols(Sema &TheSema,
   // Diagnose availability in the context of the ObjC container.
   Sema::ContextRAII SavedContext(TheSema, CD);
   for (unsigned i = 0; i < NumProtoRefs; ++i) {
-    (void)TheSema.DiagnoseUseOfDecl(ProtoRefs[i], ProtoLocs[i]);
+    (void)TheSema.DiagnoseUseOfDecl(ProtoRefs[i], ProtoLocs[i],
+                                    /*UnknownObjCClass=*/nullptr,
+                                    /*ObjCPropertyAccess=*/false,
+                                    /*AvoidPartialAvailabilityChecks=*/true);
   }
 }
 

clang/lib/Sema/SemaExpr.cpp

@@ -128,7 +128,8 @@ Sema::ShouldDiagnoseAvailabilityOfDecl(const NamedDecl *D,
 static void
 DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
                            const ObjCInterfaceDecl *UnknownObjCClass,
-                           bool ObjCPropertyAccess) {
+                           bool ObjCPropertyAccess,
+                           bool AvoidPartialAvailabilityChecks = false) {
   std::string Message;
   AvailabilityResult Result;
   const NamedDecl* OffendingDecl;
@@ -138,6 +139,8 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
     return;
 
   if (Result == AR_NotYetIntroduced) {
+    if (AvoidPartialAvailabilityChecks)
+      return;
     if (S.getCurFunctionOrMethodDecl()) {
       S.getEnclosingFunction()->HasPotentialAvailabilityViolations = true;
       return;
@@ -275,7 +278,8 @@ void Sema::MaybeSuggestAddingStaticToDecl(const FunctionDecl *Cur) {
 ///
 bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
                              const ObjCInterfaceDecl *UnknownObjCClass,
-                             bool ObjCPropertyAccess) {
+                             bool ObjCPropertyAccess,
+                             bool AvoidPartialAvailabilityChecks) {
   if (getLangOpts().CPlusPlus && isa<FunctionDecl>(D)) {
     // If there were any diagnostics suppressed by template argument deduction,
     // emit them now.
@@ -360,7 +364,8 @@ bool Sema::DiagnoseUseOfDecl(NamedDecl *D, SourceLocation Loc,
   }
 
   DiagnoseAvailabilityOfDecl(*this, D, Loc, UnknownObjCClass,
-                             ObjCPropertyAccess);
+                             ObjCPropertyAccess,
+                             AvoidPartialAvailabilityChecks);
 
   DiagnoseUnusedOfDecl(*this, D, Loc);
 

clang/test/SemaObjC/unguarded-availability.m

@@ -263,3 +263,27 @@ void with_local_struct() {
     new_int x; // expected-warning{{'new_int' is partial}}
   };
 }
+
+// rdar://33156429:
+// Avoid the warning on protocol requirements.
+
+AVAILABLE_10_12
+@protocol NewProtocol // expected-note {{'NewProtocol' has been explicitly marked partial here}}
+@end
+
+@protocol ProtocolWithNewProtocolRequirement <NewProtocol> // expected-note {{annotate 'ProtocolWithNewProtocolRequirement' with an availability attribute to silence}}
+
+@property(copy) id<NewProtocol> prop; // expected-warning {{'NewProtocol' is partial: introduced in macOS 10.12}}
+
+@end
+
+@interface BaseClass
+@end
+
+@interface ClassWithNewProtocolRequirement : BaseClass <NewProtocol>
+
+@end
+
+@interface BaseClass (CategoryWithNewProtocolRequirement) <NewProtocol>
+
+@end