[NFC][ObjC Availability] Split up DiagnoseAvailabilityOfDecl, remove redundant enumeration

[erik.pilkington]

Summary

This patch removes the enum Sema::AvailabilityDiagnostic, which is redundant with clang::AvailabilityResult, and pulls out a function, ShouldDiagnoseAvailabiltyOfDecl from DiagnoseAvailabiltyOfDecl. This is so we can call ShouldDiagnoseAvailabilityOfDecl when emitting -Wunguarded-availabilty, which is done after Sema of a function.

This patch was originally part of https://reviews.llvm.org/D23003, but it was suggested that I separate it out.

[manmanren]

Thanks,
Manman

include/clang/Sema/DelayedDiagnostic.h

public:
 
   unsigned char Kind; // actually a DDKind
   bool Triggered;
 
   SourceLocation Loc;
 
   void Destroy();
 
-  static DelayedDiagnostic makeAvailability(Sema::AvailabilityDiagnostic AD,
+  static DelayedDiagnostic makeAvailability(AvailabilityResult AR,
                                             SourceLocation Loc,
                                             const NamedDecl *D,
                                             const ObjCInterfaceDecl *UnknownObjCClass,
                                             const ObjCPropertyDecl  *ObjCProperty,
                                             StringRef Msg,
                                             bool ObjCPropertyAccess);
 
 

include/clang/Sema/Sema.h

     return DelayedDiagnostics.pushUndelayed();
   }
   void PopParsingClass(ParsingClassState state) {
     DelayedDiagnostics.popUndelayed(state);
   }
 
   void redelayDiagnostics(sema::DelayedDiagnosticPool &pool);
 
-  enum AvailabilityDiagnostic { AD_Deprecation, AD_Unavailable, AD_Partial };
-
-  void EmitAvailabilityWarning(AvailabilityDiagnostic AD,
-                               NamedDecl *D, StringRef Message,
-                               SourceLocation Loc,
+  void EmitAvailabilityWarning(AvailabilityResult AR, NamedDecl *D,
+                               StringRef Message, SourceLocation Loc,
                                const ObjCInterfaceDecl *UnknownObjCClass,
-                               const ObjCPropertyDecl  *ObjCProperty,
+                               const ObjCPropertyDecl *ObjCProperty,
                                bool ObjCPropertyAccess);
 
   bool makeUnavailableInSystemHeader(SourceLocation loc,
                                      UnavailableAttr::ImplicitReason reason);
 
   //===--------------------------------------------------------------------===//
   // Expression Parsing Callbacks: SemaExpr.cpp.
 

 
   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;
 
+  /// \brief The diagnostic we should emit for \c D, or \c AR_Available.
+  ///
+  /// \param D The declaration to check. Note that this may be altered to point
+  /// to another declaration that \c D gets it's availability from. i.e., we
+  /// walk the list of typedefs to find an availability attribute.
+  ///
+  /// \param ContextVersion The version to compare availability against.
+  AvailabilityResult
+  ShouldDiagnoseAvailabilityOfDecl(NamedDecl *&D, VersionTuple ContextVersion,
+                                   std::string *Message);
+
   const DeclContext *getCurObjCLexicalContext() const {
     const DeclContext *DC = getCurLexicalContext();
     // A category implicitly has the attribute of the interface.
     if (const ObjCCategoryDecl *CatD = dyn_cast<ObjCCategoryDecl>(DC))
       DC = CatD->getClassInterface();
     return DC;
   }
 

lib/Sema/DelayedDiagnostic.cpp

 //
 //===----------------------------------------------------------------------===//
 #include "clang/Sema/DelayedDiagnostic.h"
 #include <string.h>
 using namespace clang;
 using namespace sema;
 
 DelayedDiagnostic
-DelayedDiagnostic::makeAvailability(Sema::AvailabilityDiagnostic AD,
+DelayedDiagnostic::makeAvailability(AvailabilityResult AD,
                                     SourceLocation Loc,
                                     const NamedDecl *D,
                                     const ObjCInterfaceDecl *UnknownObjCClass,
                                     const ObjCPropertyDecl  *ObjCProperty,
                                     StringRef Msg,
                                     bool ObjCPropertyAccess) {
   DelayedDiagnostic DD;
   switch (AD) {
-    case Sema::AD_Deprecation:
-      DD.Kind = Deprecation;
-      break;
-    case Sema::AD_Unavailable:
-      DD.Kind = Unavailable;
-      break;
-    case Sema::AD_Partial:
-      llvm_unreachable("AD_Partial diags should not be delayed");
+  case AR_Deprecated:
+  case AR_Unavailable:
+  default:
+    llvm_unreachable("partial diags should not be delayed");
   }
   DD.Triggered = false;
   DD.Loc = Loc;
   DD.DeprecationData.Decl = D;
   DD.DeprecationData.UnknownObjCClass = UnknownObjCClass;
   DD.DeprecationData.ObjCProperty = ObjCProperty;
   char *MessageData = nullptr;
   if (Msg.size()) {

lib/Sema/SemaDeclAttr.cpp

       // Match the platform name.
       if (RealizedPlatform == TargetPlatform)
         return Avail;
     }
   }
   return nullptr;
 }
 
-static void DoEmitAvailabilityWarning(Sema &S, Sema::AvailabilityDiagnostic K,
+static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
                                       Decl *Ctx, const NamedDecl *D,
                                       StringRef Message, SourceLocation Loc,
                                       const ObjCInterfaceDecl *UnknownObjCClass,
                                       const ObjCPropertyDecl *ObjCProperty,
                                       bool ObjCPropertyAccess) {
   // Diagnostics for deprecated or unavailable.
   unsigned diag, diag_message, diag_fwdclass_message;
   unsigned diag_available_here = diag::note_availability_specified_here;
 
   // Matches 'diag::note_property_attribute' options.
   unsigned property_note_select;
 
   // Matches diag::note_availability_specified_here.
   unsigned available_here_select_kind;
 
   // Don't warn if our current context is deprecated or unavailable.
   switch (K) {
-  case Sema::AD_Deprecation:
+  case AR_Deprecated:
     if (isDeclDeprecated(Ctx) || isDeclUnavailable(Ctx))
       return;
     diag = !ObjCPropertyAccess ? diag::warn_deprecated
                                : diag::warn_property_method_deprecated;
     diag_message = diag::warn_deprecated_message;
     diag_fwdclass_message = diag::warn_deprecated_fwdclass_message;
     property_note_select = /* deprecated */ 0;
     available_here_select_kind = /* deprecated */ 2;
     break;
 
-  case Sema::AD_Unavailable:
+  case AR_Unavailable:
     if (isDeclUnavailable(Ctx))
       return;
     diag = !ObjCPropertyAccess ? diag::err_unavailable
                                : diag::err_property_method_unavailable;
     diag_message = diag::err_unavailable_message;
     diag_fwdclass_message = diag::warn_unavailable_fwdclass_message;
     property_note_select = /* unavailable */ 1;
     available_here_select_kind = /* unavailable */ 0;

           flagARCError();
           diag_available_here = diag::note_arc_field_with_ownership;
           break;
         }
       }
     }
     break;
 
-  case Sema::AD_Partial:
+  case AR_NotYetIntroduced:
     diag = diag::warn_partial_availability;
     diag_message = diag::warn_partial_message;
     diag_fwdclass_message = diag::warn_partial_fwdclass_message;
     property_note_select = /* partial */ 2;
     available_here_select_kind = /* partial */ 3;
     break;
+
+  case AR_Available:
+    llvm_unreachable("Warning for availability of available declaration?");
   }
 
   CharSourceRange UseRange;
   StringRef Replacement;
-  if (K == Sema::AD_Deprecation) {
+  if (K == AR_Deprecated) {
     if (auto attr = D->getAttr<DeprecatedAttr>())
       Replacement = attr->getReplacement();
     if (auto attr = getAttrForPlatform(S.Context, D))
       Replacement = attr->getReplacement();
 
     if (!Replacement.empty())
       UseRange =
           CharSourceRange::getCharRange(Loc, S.getLocForEndOfToken(Loc));

         break;
       }
     }
   }
   else
     S.Diag(D->getLocation(), diag_available_here)
         << D << available_here_select_kind;
 
-  if (K == Sema::AD_Partial)
+  if (K == AR_NotYetIntroduced)
     S.Diag(Loc, diag::note_partial_availability_silence) << D;
 }
 
 static void handleDelayedAvailabilityCheck(Sema &S, DelayedDiagnostic &DD,
                                            Decl *Ctx) {
   assert(DD.Kind == DelayedDiagnostic::Deprecation ||
          DD.Kind == DelayedDiagnostic::Unavailable);
-  Sema::AvailabilityDiagnostic AD = DD.Kind == DelayedDiagnostic::Deprecation
-                                        ? Sema::AD_Deprecation
-                                        : Sema::AD_Unavailable;
+  AvailabilityResult AR = DD.Kind == DelayedDiagnostic::Deprecation
+                              ? AR_Deprecated
+                              : AR_Unavailable;
   DD.Triggered = true;
   DoEmitAvailabilityWarning(
-      S, AD, Ctx, DD.getDeprecationDecl(), DD.getDeprecationMessage(), DD.Loc,
+      S, AR, Ctx, DD.getDeprecationDecl(), DD.getDeprecationMessage(), DD.Loc,
       DD.getUnknownObjCClass(), DD.getObjCProperty(), false);
 }
 
 void Sema::PopParsingDeclaration(ParsingDeclState state, Decl *decl) {
   assert(DelayedDiagnostics.getCurrentPool());
   DelayedDiagnosticPool &poppedPool = *DelayedDiagnostics.getCurrentPool();
   DelayedDiagnostics.popWithoutEmitting(state);
 

 /// been delayed in the current context instead of in the given pool.
 /// Essentially, this just moves them to the current pool.
 void Sema::redelayDiagnostics(DelayedDiagnosticPool &pool) {
   DelayedDiagnosticPool *curPool = DelayedDiagnostics.getCurrentPool();
   assert(curPool && "re-emitting in undelayed context not supported");
   curPool->steal(pool);
 }
 
-void Sema::EmitAvailabilityWarning(AvailabilityDiagnostic AD,
+void Sema::EmitAvailabilityWarning(AvailabilityResult AR,
                                    NamedDecl *D, StringRef Message,
                                    SourceLocation Loc,
                                    const ObjCInterfaceDecl *UnknownObjCClass,
                                    const ObjCPropertyDecl  *ObjCProperty,
                                    bool ObjCPropertyAccess) {
   // Delay if we're currently parsing a declaration.
-  if (DelayedDiagnostics.shouldDelayDiagnostics() && AD != AD_Partial) {
+  if (DelayedDiagnostics.shouldDelayDiagnostics() &&
+      AR != AR_NotYetIntroduced) {
     DelayedDiagnostics.add(DelayedDiagnostic::makeAvailability(
-        AD, Loc, D, UnknownObjCClass, ObjCProperty, Message,
+        AR, Loc, D, UnknownObjCClass, ObjCProperty, Message,
         ObjCPropertyAccess));
     return;
   }
 
   Decl *Ctx = cast<Decl>(getCurLexicalContext());
-  DoEmitAvailabilityWarning(*this, AD, Ctx, D, Message, Loc, UnknownObjCClass,
+  DoEmitAvailabilityWarning(*this, AR, 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))

lib/Sema/SemaExpr.cpp

static bool HasRedeclarationWithoutAvailabilityInCategory(const Decl *D) {
   for (const ObjCCategoryDecl *Cat : OID->visible_categories())
     if (ObjCMethodDecl *CatMeth =
             Cat->getMethod(OMD->getSelector(), OMD->isInstanceMethod()))
       if (!CatMeth->hasAttr<AvailabilityAttr>())
         return true;
   return false;
 }
 
-static AvailabilityResult
-DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
-                           const ObjCInterfaceDecl *UnknownObjCClass,
-                           bool ObjCPropertyAccess) {
-  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, ContextVersion);
+AvailabilityResult Sema::ShouldDiagnoseAvailabilityOfDecl(
+    NamedDecl *&D, VersionTuple ContextVersion, std::string *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.
   while (const TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D)) {
     if (Result == AR_Available) {
       if (const TagType *TT = TD->getUnderlyingType()->getAs<TagType>()) {
         D = TT->getDecl();
-        Result = D->getAvailability(&Message, ContextVersion);
+        Result = D->getAvailability(Message, ContextVersion);
         continue;
       }
     }
     break;
   }
-    
   // Forward class declarations get their attributes from their definition.
   if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
     if (IDecl->getDefinition()) {
       D = IDecl->getDefinition();
-      Result = D->getAvailability(&Message, ContextVersion);
+      Result = D->getAvailability(Message, ContextVersion);
     }
   }
 
   if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D))
     if (Result == AR_Available) {
       const DeclContext *DC = ECD->getDeclContext();
       if (const EnumDecl *TheEnumDecl = dyn_cast<EnumDecl>(DC))
-        Result = TheEnumDecl->getAvailability(&Message, ContextVersion);
-    }
-
-  const ObjCPropertyDecl *ObjCPDecl = nullptr;
-  if (Result == AR_Deprecated || Result == AR_Unavailable ||
-      Result == AR_NotYetIntroduced) {
-    if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
-      if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
-        AvailabilityResult PDeclResult =
-            PD->getAvailability(nullptr, ContextVersion);
-        if (PDeclResult == Result)
-          ObjCPDecl = PD;
-      }
-    }
+        Result = TheEnumDecl->getAvailability(Message, ContextVersion);
     }
-  
   switch (Result) {
-    case AR_Available:
-      break;
+    return Result;
 
-    case AR_Deprecated:
-      if (S.getCurContextAvailability() != AR_Deprecated)
-        S.EmitAvailabilityWarning(Sema::AD_Deprecation,
-                                  D, Message, Loc, UnknownObjCClass, ObjCPDecl,
-                                  ObjCPropertyAccess);
-      break;
+  case AR_Unavailable:
+    return getCurContextAvailability() != Result ? Result : AR_Available;
 
-    case AR_NotYetIntroduced: {
-      // Don't do this for enums, they can't be redeclared.
-      if (isa<EnumConstantDecl>(D) || isa<EnumDecl>(D))
-        break;
- 
-      bool Warn = !D->getAttr<AvailabilityAttr>()->isInherited();
-      // Objective-C method declarations in categories are not modelled as
-      // redeclarations, so manually look for a redeclaration in a category
-      // if necessary.
-      if (Warn && HasRedeclarationWithoutAvailabilityInCategory(D))
-        Warn = false;
-      // In general, D will point to the most recent redeclaration. However,
-      // for `@class A;` decls, this isn't true -- manually go through the
-      // redecl chain in that case.
-      if (Warn && isa<ObjCInterfaceDecl>(D))
-        for (Decl *Redecl = D->getMostRecentDecl(); Redecl && Warn;
-             Redecl = Redecl->getPreviousDecl())
-          if (!Redecl->hasAttr<AvailabilityAttr>() ||
-              Redecl->getAttr<AvailabilityAttr>()->isInherited())
-            Warn = false;
- 
-      if (Warn)
-        S.EmitAvailabilityWarning(Sema::AD_Partial, D, Message, Loc,
-                                  UnknownObjCClass, ObjCPDecl,
-                                  ObjCPropertyAccess);
-      break;
-    }
+      return AR_Available;
+    return Warn ? AR_NotYetIntroduced : AR_Available;
+  }
+  }
 
-    case AR_Unavailable:
-      if (S.getCurContextAvailability() != AR_Unavailable)
-        S.EmitAvailabilityWarning(Sema::AD_Unavailable,
-                                  D, Message, Loc, UnknownObjCClass, ObjCPDecl,
-                                  ObjCPropertyAccess);
-      break;
+static void
+DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
+                           const ObjCInterfaceDecl *UnknownObjCClass,
+                           bool ObjCPropertyAccess) {
+  VersionTuple ContextVersion;
+  if (const DeclContext *DC = S.getCurObjCLexicalContext())
+    ContextVersion = S.getVersionForDecl(cast<Decl>(DC));
 
-    }
-  return Result;
+  std::string Message;
+  // See if this declaration is unavailable, deprecated, or partial in the
+  // current context.
+  if (AvailabilityResult Result =
+          S.ShouldDiagnoseAvailabilityOfDecl(D, ContextVersion, &Message)) {
+
+    const ObjCPropertyDecl *ObjCPDecl = nullptr;
+    if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
+      if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
+        AvailabilityResult PDeclResult =
+            PD->getAvailability(nullptr, ContextVersion);
+        if (PDeclResult == Result)
+          ObjCPDecl = PD;
+      }
+    }
+
+    S.EmitAvailabilityWarning(Result, D, Message, Loc, UnknownObjCClass,
+                              ObjCPDecl, ObjCPropertyAccess);
 }
 
 /// \brief Emit a note explaining that this function is deleted.
 void Sema::NoteDeletedFunction(FunctionDecl *Decl) {
   assert(Decl->isDeleted());
 
   CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Decl);