[Sema][ObjC] Infer availability of +new from availability of -init.

When defined in NSObject, +new will call -init. If -init has been marked
unavailable, diagnose uses of +new.

rdar://18335828

Differential revision: https://reviews.llvm.org/D51189

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341874 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 8 deletions

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index db5df4db80..b58976a729 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -6967,8 +6967,12 @@ static const AvailabilityAttr *getAttrForPlatform(ASTContext &Context,
 /// \param D The declaration to check.
 /// \param Message If non-null, this will be populated with the message from
 /// the availability attribute that is selected.
+/// \param ClassReceiver If we're checking the the method of a class message
+/// send, the class. Otherwise nullptr.
 static std::pair<AvailabilityResult, const NamedDecl *>
-ShouldDiagnoseAvailabilityOfDecl(const NamedDecl *D, std::string *Message) {
+ShouldDiagnoseAvailabilityOfDecl(Sema &S, const NamedDecl *D,
+                                 std::string *Message,
+                                 ObjCInterfaceDecl *ClassReceiver) {
   AvailabilityResult Result = D->getAvailability(Message);
 
   // For typedefs, if the typedef declaration appears available look
@@ -7001,6 +7005,20 @@ ShouldDiagnoseAvailabilityOfDecl(const NamedDecl *D, std::string *Message) {
       }
     }
 
+  // For +new, infer availability from -init.
+  if (const auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
+    if (S.NSAPIObj && ClassReceiver) {
+      ObjCMethodDecl *Init = ClassReceiver->lookupInstanceMethod(
+          S.NSAPIObj->getInitSelector());
+      if (Init && Result == AR_Available && MD->isClassMethod() &&
+          MD->getSelector() == S.NSAPIObj->getNewSelector() &&
+          MD->definedInNSObject(S.getASTContext())) {
+        Result = Init->getAvailability(Message);
+        D = Init;
+      }
+    }
+  }
+
   return {Result, D};
 }
 
@@ -7589,7 +7607,8 @@ class DiagnoseUnguardedAvailability
   SmallVector<VersionTuple, 8> AvailabilityStack;
   SmallVector<const Stmt *, 16> StmtStack;
 
-  void DiagnoseDeclAvailability(NamedDecl *D, SourceRange Range);
+  void DiagnoseDeclAvailability(NamedDecl *D, SourceRange Range,
+                                ObjCInterfaceDecl *ClassReceiver = nullptr);
 
 public:
   DiagnoseUnguardedAvailability(Sema &SemaRef, Decl *Ctx)
@@ -7631,9 +7650,15 @@ public:
   }
 
   bool VisitObjCMessageExpr(ObjCMessageExpr *Msg) {
-    if (ObjCMethodDecl *D = Msg->getMethodDecl())
+    if (ObjCMethodDecl *D = Msg->getMethodDecl()) {
+      ObjCInterfaceDecl *ID = nullptr;
+      QualType ReceiverTy = Msg->getClassReceiver();
+      if (!ReceiverTy.isNull() && ReceiverTy->getAsObjCInterfaceType())
+        ID = ReceiverTy->getAsObjCInterfaceType()->getInterface();
+
       DiagnoseDeclAvailability(
-          D, SourceRange(Msg->getSelectorStartLoc(), Msg->getEndLoc()));
+          D, SourceRange(Msg->getSelectorStartLoc(), Msg->getEndLoc()), ID);
+    }
     return true;
   }
 
@@ -7659,11 +7684,11 @@ public:
 };
 
 void DiagnoseUnguardedAvailability::DiagnoseDeclAvailability(
-    NamedDecl *D, SourceRange Range) {
+    NamedDecl *D, SourceRange Range, ObjCInterfaceDecl *ReceiverClass) {
   AvailabilityResult Result;
   const NamedDecl *OffendingDecl;
   std::tie(Result, OffendingDecl) =
-    ShouldDiagnoseAvailabilityOfDecl(D, nullptr);
+      ShouldDiagnoseAvailabilityOfDecl(SemaRef, D, nullptr, ReceiverClass);
   if (Result != AR_Available) {
     // All other diagnostic kinds have already been handled in
     // DiagnoseAvailabilityOfDecl.
@@ -7845,12 +7870,14 @@ void Sema::DiagnoseAvailabilityOfDecl(NamedDecl *D,
                                       ArrayRef<SourceLocation> Locs,
                                       const ObjCInterfaceDecl *UnknownObjCClass,
                                       bool ObjCPropertyAccess,
-                                      bool AvoidPartialAvailabilityChecks) {
+                                      bool AvoidPartialAvailabilityChecks,
+                                      ObjCInterfaceDecl *ClassReceiver) {
   std::string Message;
   AvailabilityResult Result;
   const NamedDecl* OffendingDecl;
   // See if this declaration is unavailable, deprecated, or partial.
-  std::tie(Result, OffendingDecl) = ShouldDiagnoseAvailabilityOfDecl(D, &Message);
+  std::tie(Result, OffendingDecl) =
+      ShouldDiagnoseAvailabilityOfDecl(*this, D, &Message, ClassReceiver);
   if (Result == AR_Available)
     return;