[ObjC] Consider availability of context when emitting availability warnings

This means that a function marked with an availability attribute can safely
refer to a declaration that is greater than the deployment target, but less then
or equal to the context availability without -Wpartial-availability firing.

Differential revision: https://reviews.llvm.org/D22697

llvm-svn: 277058

clang/include/clang/AST/DeclBase.h

@@ -17,6 +17,7 @@
 #include "clang/AST/AttrIterator.h"
 #include "clang/AST/DeclarationName.h"
 #include "clang/Basic/Specifiers.h"
+#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
@@ -603,7 +604,12 @@ public:
   /// AR_Available, will be set to a (possibly empty) message
   /// describing why the declaration has not been introduced, is
   /// deprecated, or is unavailable.
-  AvailabilityResult getAvailability(std::string *Message = nullptr) const;
+  ///
+  /// \param EnclosingVersion The version to compare with. If empty, assume the
+  /// deployment target version.
+  AvailabilityResult
+  getAvailability(std::string *Message = nullptr,
+                  VersionTuple EnclosingVersion = VersionTuple()) const;
 
   /// \brief Determine whether this declaration is marked 'deprecated'.
   ///

clang/include/clang/Sema/Sema.h

@@ -9596,7 +9596,12 @@ public:
   }
 
   AvailabilityResult getCurContextAvailability() const;
-  
+
+  /// \brief Get the verison that this context implies.
+  /// For instance, a method in an interface that is annotated with an
+  /// availability attribuite effectively has the availability of the interface.
+  VersionTuple getVersionForDecl(const Decl *Ctx) const;
+
   const DeclContext *getCurObjCLexicalContext() const {
     const DeclContext *DC = getCurLexicalContext();
     // A category implicitly has the attribute of the interface.

clang/lib/AST/DeclBase.cpp

@@ -400,11 +400,12 @@ const Attr *Decl::getDefiningAttr() const {
 /// diagnostics.
 static AvailabilityResult CheckAvailability(ASTContext &Context,
                                             const AvailabilityAttr *A,
-                                            std::string *Message) {
-  VersionTuple TargetMinVersion =
-    Context.getTargetInfo().getPlatformMinVersion();
+                                            std::string *Message,
+                                            VersionTuple EnclosingVersion) {
+  if (EnclosingVersion.empty())
+    EnclosingVersion = Context.getTargetInfo().getPlatformMinVersion();
 
-  if (TargetMinVersion.empty())
+  if (EnclosingVersion.empty())
     return AR_Available;
 
   // Check if this is an App Extension "platform", and if so chop off
@@ -449,7 +450,7 @@ static AvailabilityResult CheckAvailability(ASTContext &Context,
 
   // Make sure that this declaration has already been introduced.
   if (!A->getIntroduced().empty() && 
-      TargetMinVersion < A->getIntroduced()) {
+      EnclosingVersion < A->getIntroduced()) {
     if (Message) {
       Message->clear();
       llvm::raw_string_ostream Out(*Message);
@@ -463,7 +464,7 @@ static AvailabilityResult CheckAvailability(ASTContext &Context,
   }
 
   // Make sure that this declaration hasn't been obsoleted.
-  if (!A->getObsoleted().empty() && TargetMinVersion >= A->getObsoleted()) {
+  if (!A->getObsoleted().empty() && EnclosingVersion >= A->getObsoleted()) {
     if (Message) {
       Message->clear();
       llvm::raw_string_ostream Out(*Message);
@@ -477,7 +478,7 @@ static AvailabilityResult CheckAvailability(ASTContext &Context,
   }
 
   // Make sure that this declaration hasn't been deprecated.
-  if (!A->getDeprecated().empty() && TargetMinVersion >= A->getDeprecated()) {
+  if (!A->getDeprecated().empty() && EnclosingVersion >= A->getDeprecated()) {
     if (Message) {
       Message->clear();
       llvm::raw_string_ostream Out(*Message);
@@ -493,9 +494,10 @@ static AvailabilityResult CheckAvailability(ASTContext &Context,
   return AR_Available;
 }
 
-AvailabilityResult Decl::getAvailability(std::string *Message) const {
+AvailabilityResult Decl::getAvailability(std::string *Message,
+                                         VersionTuple EnclosingVersion) const {
   if (auto *FTD = dyn_cast<FunctionTemplateDecl>(this))
-    return FTD->getTemplatedDecl()->getAvailability(Message);
+    return FTD->getTemplatedDecl()->getAvailability(Message, EnclosingVersion);
 
   AvailabilityResult Result = AR_Available;
   std::string ResultMessage;
@@ -520,7 +522,7 @@ AvailabilityResult Decl::getAvailability(std::string *Message) const {
 
     if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
       AvailabilityResult AR = CheckAvailability(getASTContext(), Availability,
-                                                Message);
+                                                Message, EnclosingVersion);
 
       if (AR == AR_Unavailable)
         return AR_Unavailable;
@@ -579,8 +581,8 @@ bool Decl::isWeakImported() const {
       return true;
 
     if (const auto *Availability = dyn_cast<AvailabilityAttr>(A)) {
-      if (CheckAvailability(getASTContext(), Availability,
-                            nullptr) == AR_NotYetIntroduced)
+      if (CheckAvailability(getASTContext(), Availability, nullptr,
+                            VersionTuple()) == AR_NotYetIntroduced)
         return true;
     }
   }

clang/lib/Sema/SemaDeclAttr.cpp

@@ -6484,3 +6484,26 @@ void Sema::EmitAvailabilityWarning(AvailabilityDiagnostic AD,
   DoEmitAvailabilityWarning(*this, AD, Ctx, D, Message, Loc, UnknownObjCClass,
                             ObjCProperty, ObjCPropertyAccess);
 }
+
+VersionTuple Sema::getVersionForDecl(const Decl *D) const {
+  assert(D && "Expected a declaration here!");
+
+  VersionTuple DeclVersion;
+  if (const auto *AA = getAttrForPlatform(getASTContext(), D))
+    DeclVersion = AA->getIntroduced();
+
+  const ObjCInterfaceDecl *Interface = nullptr;
+
+  if (const auto *MD = dyn_cast<ObjCMethodDecl>(D))
+    Interface = MD->getClassInterface();
+  else if (const auto *ID = dyn_cast<ObjCImplementationDecl>(D))
+    Interface = ID->getClassInterface();
+
+  if (Interface) {
+    if (const auto *AA = getAttrForPlatform(getASTContext(), Interface))
+      if (AA->getIntroduced() > DeclVersion)
+        DeclVersion = AA->getIntroduced();
+  }
+
+  return DeclVersion;
+}

clang/lib/Sema/SemaExpr.cpp

@@ -107,9 +107,14 @@ static AvailabilityResult
 DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
                            const ObjCInterfaceDecl *UnknownObjCClass,
                            bool ObjCPropertyAccess) {
-  // See if this declaration is unavailable or deprecated.
+  VersionTuple ContextVersion;
+  if (const DeclContext *DC = S.getCurObjCLexicalContext())
+    ContextVersion = S.getVersionForDecl(cast<Decl>(DC));
+
+  // See if this declaration is unavailable, deprecated, or partial in the
+  // current context.
   std::string Message;
-  AvailabilityResult Result = D->getAvailability(&Message);
+  AvailabilityResult Result = D->getAvailability(&Message, ContextVersion);
 
   // For typedefs, if the typedef declaration appears available look
   // to the underlying type to see if it is more restrictive.
@@ -117,7 +122,7 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
     if (Result == AR_Available) {
       if (const TagType *TT = TD->getUnderlyingType()->getAs<TagType>()) {
         D = TT->getDecl();
-        Result = D->getAvailability(&Message);
+        Result = D->getAvailability(&Message, ContextVersion);
         continue;
       }
     }
@@ -128,7 +133,7 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
     if (IDecl->getDefinition()) {
       D = IDecl->getDefinition();
-      Result = D->getAvailability(&Message);
+      Result = D->getAvailability(&Message, ContextVersion);
     }
   }
 
@@ -136,7 +141,7 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
     if (Result == AR_Available) {
       const DeclContext *DC = ECD->getDeclContext();
       if (const EnumDecl *TheEnumDecl = dyn_cast<EnumDecl>(DC))
-        Result = TheEnumDecl->getAvailability(&Message);
+        Result = TheEnumDecl->getAvailability(&Message, ContextVersion);
     }
 
   const ObjCPropertyDecl *ObjCPDecl = nullptr;
@@ -144,7 +149,8 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
       Result == AR_NotYetIntroduced) {
     if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
       if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
-        AvailabilityResult PDeclResult = PD->getAvailability(nullptr);
+        AvailabilityResult PDeclResult =
+            PD->getAvailability(nullptr, ContextVersion);
         if (PDeclResult == Result)
           ObjCPDecl = PD;
       }
@@ -198,7 +204,7 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
       break;
 
     }
-    return Result;
+  return Result;
 }
 
 /// \brief Emit a note explaining that this function is deleted.

clang/test/SemaObjC/attr-availability.m

@@ -294,3 +294,34 @@ __attribute__((objc_root_class))
   [obj method]; // expected-error{{'method' is unavailable}}
 }
 @end
+
+#if defined(WARN_PARTIAL)
+
+int fn_10_7() __attribute__((availability(macosx, introduced=10.7))); // expected-note{{marked partial here}}
+int fn_10_8() __attribute__((availability(macosx, introduced=10.8))) { // expected-note{{marked partial here}}
+  return fn_10_7();
+}
+
+__attribute__((objc_root_class))
+@interface LookupAvailabilityBase
+-(void) method1;
+@end
+
+@implementation LookupAvailabilityBase
+-(void)method1 { fn_10_7(); } // expected-warning{{partial}} expected-note{{explicitly redeclare}}
+@end
+
+__attribute__((availability(macosx, introduced=10.7)))
+@interface LookupAvailability : LookupAvailabilityBase
+- (void)method2;
+- (void)method3;
+- (void)method4 __attribute__((availability(macosx, introduced=10.8)));
+@end
+
+@implementation LookupAvailability
+-(void)method2 { fn_10_7(); }
+-(void)method3 { fn_10_8(); } // expected-warning{{partial}} expected-note{{explicitly redeclare}}
+-(void)method4 { fn_10_8(); }
+@end
+
+#endif