[Sema] Don't allow -Wunguarded-availability to be silenced with redecls

Differential revision: https://reviews.llvm.org/D33816

llvm-svn: 307175

3 files changed, 114 insertions, 104 deletions

diff --git a/clang/lib/Sema/DelayedDiagnostic.cpp b/clang/lib/Sema/DelayedDiagnostic.cpp
index 2fa5718d4e9..3d321d561e6 100644
--- a/clang/lib/Sema/DelayedDiagnostic.cpp
+++ b/clang/lib/Sema/DelayedDiagnostic.cpp
@@ -22,7 +22,8 @@ using namespace sema;
 DelayedDiagnostic
 DelayedDiagnostic::makeAvailability(AvailabilityResult AR,
                                     SourceLocation Loc,
-                                    const NamedDecl *D,
+                                    const NamedDecl *ReferringDecl,
+                                    const NamedDecl *OffendingDecl,
                                     const ObjCInterfaceDecl *UnknownObjCClass,
                                     const ObjCPropertyDecl  *ObjCProperty,
                                     StringRef Msg,
@@ -31,7 +32,8 @@ DelayedDiagnostic::makeAvailability(AvailabilityResult AR,
   DD.Kind = Availability;
   DD.Triggered = false;
   DD.Loc = Loc;
-  DD.AvailabilityData.Decl = D;
+  DD.AvailabilityData.ReferringDecl = ReferringDecl;
+  DD.AvailabilityData.OffendingDecl = OffendingDecl;
   DD.AvailabilityData.UnknownObjCClass = UnknownObjCClass;
   DD.AvailabilityData.ObjCProperty = ObjCProperty;
   char *MessageData = nullptr;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 1929bc53918..5fb79a6bf63 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -6929,8 +6929,34 @@ shouldDiagnoseAvailabilityByDefault(const ASTContext &Context,
          DeclVersion >= ForceAvailabilityFromVersion;
 }
 
+static NamedDecl *findEnclosingDeclToAnnotate(Decl *OrigCtx) {
+  for (Decl *Ctx = OrigCtx; Ctx;
+       Ctx = cast_or_null<Decl>(Ctx->getDeclContext())) {
+    if (isa<TagDecl>(Ctx) || isa<FunctionDecl>(Ctx) || isa<ObjCMethodDecl>(Ctx))
+      return cast<NamedDecl>(Ctx);
+    if (auto *CD = dyn_cast<ObjCContainerDecl>(Ctx)) {
+      if (auto *Imp = dyn_cast<ObjCImplDecl>(Ctx))
+        return Imp->getClassInterface();
+      return CD;
+    }
+  }
+
+  return dyn_cast<NamedDecl>(OrigCtx);
+}
+
+/// Actually emit an availability diagnostic for a reference to an unavailable
+/// decl.
+///
+/// \param Ctx The context that the reference occurred in
+/// \param ReferringDecl The exact declaration that was referenced.
+/// \param OffendingDecl A related decl to \c ReferringDecl that has an
+/// availability attribute corrisponding to \c K attached to it. Note that this
+/// may not be the same as ReferringDecl, i.e. if an EnumDecl is annotated and
+/// we refer to a member EnumConstantDecl, ReferringDecl is the EnumConstantDecl
+/// and OffendingDecl is the EnumDecl.
 static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
-                                      Decl *Ctx, const NamedDecl *D,
+                                      Decl *Ctx, const NamedDecl *ReferringDecl,
+                                      const NamedDecl *OffendingDecl,
                                       StringRef Message, SourceLocation Loc,
                                       const ObjCInterfaceDecl *UnknownObjCClass,
                                       const ObjCPropertyDecl *ObjCProperty,
@@ -6938,7 +6964,7 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
   // Diagnostics for deprecated or unavailable.
   unsigned diag, diag_message, diag_fwdclass_message;
   unsigned diag_available_here = diag::note_availability_specified_here;
-  SourceLocation NoteLocation = D->getLocation();
+  SourceLocation NoteLocation = OffendingDecl->getLocation();
 
   // Matches 'diag::note_property_attribute' options.
   unsigned property_note_select;
@@ -6947,7 +6973,7 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
   unsigned available_here_select_kind;
 
   VersionTuple DeclVersion;
-  if (const AvailabilityAttr *AA = getAttrForPlatform(S.Context, D))
+  if (const AvailabilityAttr *AA = getAttrForPlatform(S.Context, OffendingDecl))
     DeclVersion = AA->getIntroduced();
 
   if (!ShouldDiagnoseAvailabilityInContext(S, K, DeclVersion, Ctx))
@@ -6961,7 +6987,7 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
     diag_fwdclass_message = diag::warn_deprecated_fwdclass_message;
     property_note_select = /* deprecated */ 0;
     available_here_select_kind = /* deprecated */ 2;
-    if (const auto *attr = D->getAttr<DeprecatedAttr>())
+    if (const auto *attr = OffendingDecl->getAttr<DeprecatedAttr>())
       NoteLocation = attr->getLocation();
     break;
 
@@ -6973,13 +6999,14 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
     property_note_select = /* unavailable */ 1;
     available_here_select_kind = /* unavailable */ 0;
 
-    if (auto attr = D->getAttr<UnavailableAttr>()) {
+    if (auto attr = OffendingDecl->getAttr<UnavailableAttr>()) {
       if (attr->isImplicit() && attr->getImplicitReason()) {
         // Most of these failures are due to extra restrictions in ARC;
         // reflect that in the primary diagnostic when applicable.
         auto flagARCError = [&] {
           if (S.getLangOpts().ObjCAutoRefCount &&
-              S.getSourceManager().isInSystemHeader(D->getLocation()))
+              S.getSourceManager().isInSystemHeader(
+                  OffendingDecl->getLocation()))
             diag = diag::err_unavailable_in_arc;
         };
 
@@ -7022,7 +7049,8 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
     // not specified for deployment targets >= to iOS 11 or equivalent or
     // for declarations that were introduced in iOS 11 (macOS 10.13, ...) or
     // later.
-    const AvailabilityAttr *AA = getAttrForPlatform(S.getASTContext(), D);
+    const AvailabilityAttr *AA =
+        getAttrForPlatform(S.getASTContext(), OffendingDecl);
     VersionTuple Introduced = AA->getIntroduced();
     bool NewWarning = shouldDiagnoseAvailabilityByDefault(
         S.Context, S.Context.getTargetInfo().getPlatformMinVersion(),
@@ -7045,9 +7073,9 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
   CharSourceRange UseRange;
   StringRef Replacement;
   if (K == AR_Deprecated) {
-    if (auto attr = D->getAttr<DeprecatedAttr>())
+    if (auto attr = OffendingDecl->getAttr<DeprecatedAttr>())
       Replacement = attr->getReplacement();
-    if (auto attr = getAttrForPlatform(S.Context, D))
+    if (auto attr = getAttrForPlatform(S.Context, OffendingDecl))
       Replacement = attr->getReplacement();
 
     if (!Replacement.empty())
@@ -7056,21 +7084,21 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
   }
 
   if (!Message.empty()) {
-    S.Diag(Loc, diag_message) << D << Message
+    S.Diag(Loc, diag_message) << ReferringDecl << Message
       << (UseRange.isValid() ?
           FixItHint::CreateReplacement(UseRange, Replacement) : FixItHint());
     if (ObjCProperty)
       S.Diag(ObjCProperty->getLocation(), diag::note_property_attribute)
           << ObjCProperty->getDeclName() << property_note_select;
   } else if (!UnknownObjCClass) {
-    S.Diag(Loc, diag) << D
+    S.Diag(Loc, diag) << ReferringDecl
       << (UseRange.isValid() ?
           FixItHint::CreateReplacement(UseRange, Replacement) : FixItHint());
     if (ObjCProperty)
       S.Diag(ObjCProperty->getLocation(), diag::note_property_attribute)
           << ObjCProperty->getDeclName() << property_note_select;
   } else {
-    S.Diag(Loc, diag_fwdclass_message) << D
+    S.Diag(Loc, diag_fwdclass_message) << ReferringDecl
       << (UseRange.isValid() ?
           FixItHint::CreateReplacement(UseRange, Replacement) : FixItHint());
     S.Diag(UnknownObjCClass->getLocation(), diag::note_forward_class);
@@ -7078,16 +7106,16 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
 
   // The declaration can have multiple availability attributes, we are looking
   // at one of them.
-  const AvailabilityAttr *A = getAttrForPlatform(S.Context, D);
+  const AvailabilityAttr *A = getAttrForPlatform(S.Context, OffendingDecl);
   if (A && A->isInherited()) {
-    for (const Decl *Redecl = D->getMostRecentDecl(); Redecl;
+    for (const Decl *Redecl = OffendingDecl->getMostRecentDecl(); Redecl;
          Redecl = Redecl->getPreviousDecl()) {
       const AvailabilityAttr *AForRedecl = getAttrForPlatform(S.Context,
                                                               Redecl);
       if (AForRedecl && !AForRedecl->isInherited()) {
         // If D is a declaration with inherited attributes, the note should
         // point to the declaration with actual attributes.
-        S.Diag(Redecl->getLocation(), diag_available_here) << D
+        S.Diag(Redecl->getLocation(), diag_available_here) << OffendingDecl
             << available_here_select_kind;
         break;
       }
@@ -7095,10 +7123,19 @@ static void DoEmitAvailabilityWarning(Sema &S, AvailabilityResult K,
   }
   else
     S.Diag(NoteLocation, diag_available_here)
-        << D << available_here_select_kind;
+        << OffendingDecl << available_here_select_kind;
 
   if (K == AR_NotYetIntroduced)
-    S.Diag(Loc, diag::note_partial_availability_silence) << D;
+    if (const auto *Enclosing = findEnclosingDeclToAnnotate(Ctx)) {
+      if (auto *TD = dyn_cast<TagDecl>(Enclosing))
+        if (TD->getDeclName().isEmpty()) {
+          S.Diag(TD->getLocation(), diag::note_partial_availability_silence)
+              << /*Anonymous*/1 << TD->getKindName();
+          return;
+        }
+      S.Diag(Enclosing->getLocation(), diag::note_partial_availability_silence)
+          << /*Named*/0 << Enclosing;
+    }
 }
 
 static void handleDelayedAvailabilityCheck(Sema &S, DelayedDiagnostic &DD,
@@ -7108,9 +7145,9 @@ static void handleDelayedAvailabilityCheck(Sema &S, DelayedDiagnostic &DD,
 
   DD.Triggered = true;
   DoEmitAvailabilityWarning(
-      S, DD.getAvailabilityResult(), Ctx, DD.getAvailabilityDecl(),
-      DD.getAvailabilityMessage(), DD.Loc, DD.getUnknownObjCClass(),
-      DD.getObjCProperty(), false);
+      S, DD.getAvailabilityResult(), Ctx, DD.getAvailabilityReferringDecl(),
+      DD.getAvailabilityOffendingDecl(), DD.getAvailabilityMessage(), DD.Loc,
+      DD.getUnknownObjCClass(), DD.getObjCProperty(), false);
 }
 
 void Sema::PopParsingDeclaration(ParsingDeclState state, Decl *decl) {
@@ -7169,22 +7206,25 @@ void Sema::redelayDiagnostics(DelayedDiagnosticPool &pool) {
 }
 
 void Sema::EmitAvailabilityWarning(AvailabilityResult AR,
-                                   NamedDecl *D, StringRef Message,
-                                   SourceLocation Loc,
+                                   const NamedDecl *ReferringDecl,
+                                   const NamedDecl *OffendingDecl,
+                                   StringRef Message, SourceLocation Loc,
                                    const ObjCInterfaceDecl *UnknownObjCClass,
-                                   const ObjCPropertyDecl  *ObjCProperty,
+                                   const ObjCPropertyDecl *ObjCProperty,
                                    bool ObjCPropertyAccess) {
   // Delay if we're currently parsing a declaration.
   if (DelayedDiagnostics.shouldDelayDiagnostics()) {
-    DelayedDiagnostics.add(DelayedDiagnostic::makeAvailability(
-        AR, Loc, D, UnknownObjCClass, ObjCProperty, Message,
-        ObjCPropertyAccess));
+    DelayedDiagnostics.add(
+        DelayedDiagnostic::makeAvailability(
+            AR, Loc, ReferringDecl, OffendingDecl, UnknownObjCClass,
+            ObjCProperty, Message, ObjCPropertyAccess));
     return;
   }
 
   Decl *Ctx = cast<Decl>(getCurLexicalContext());
-  DoEmitAvailabilityWarning(*this, AR, Ctx, D, Message, Loc, UnknownObjCClass,
-                            ObjCProperty, ObjCPropertyAccess);
+  DoEmitAvailabilityWarning(*this, AR, Ctx, ReferringDecl, OffendingDecl,
+                            Message, Loc, UnknownObjCClass, ObjCProperty,
+                            ObjCPropertyAccess);
 }
 
 namespace {
@@ -7336,19 +7376,21 @@ public:
 
 void DiagnoseUnguardedAvailability::DiagnoseDeclAvailability(
     NamedDecl *D, SourceRange Range) {
-
-  VersionTuple ContextVersion = AvailabilityStack.back();
-  if (AvailabilityResult Result =
-          SemaRef.ShouldDiagnoseAvailabilityOfDecl(D, nullptr)) {
+  AvailabilityResult Result;
+  const NamedDecl *OffendingDecl;
+  std::tie(Result, OffendingDecl) =
+      SemaRef.ShouldDiagnoseAvailabilityOfDecl(D, nullptr);
+  if (Result != AR_Available) {
     // All other diagnostic kinds have already been handled in
     // DiagnoseAvailabilityOfDecl.
     if (Result != AR_NotYetIntroduced)
       return;
 
-    const AvailabilityAttr *AA = getAttrForPlatform(SemaRef.getASTContext(), D);
+    const AvailabilityAttr *AA =
+      getAttrForPlatform(SemaRef.getASTContext(), OffendingDecl);
     VersionTuple Introduced = AA->getIntroduced();
 
-    if (ContextVersion >= Introduced)
+    if (AvailabilityStack.back() >= Introduced)
       return;
 
     // If the context of this function is less available than D, we should not
@@ -7373,8 +7415,9 @@ void DiagnoseUnguardedAvailability::DiagnoseDeclAvailability(
                SemaRef.getASTContext().getTargetInfo().getPlatformName())
         << Introduced.getAsString();
 
-    SemaRef.Diag(D->getLocation(), diag::note_availability_specified_here)
-        << D << /* partial */ 3;
+    SemaRef.Diag(OffendingDecl->getLocation(),
+                 diag::note_availability_specified_here)
+        << OffendingDecl << /* partial */ 3;
 
     auto FixitDiag =
         SemaRef.Diag(Range.getBegin(), diag::note_unguarded_available_silence)
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index f49df6b3216..5a22322aa03 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -87,24 +87,9 @@ static void DiagnoseUnusedOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc) {
   }
 }
 
-static bool HasRedeclarationWithoutAvailabilityInCategory(const Decl *D) {
-  const auto *OMD = dyn_cast<ObjCMethodDecl>(D);
-  if (!OMD)
-    return false;
-  const ObjCInterfaceDecl *OID = OMD->getClassInterface();
-  if (!OID)
-    return false;
-
-  for (const ObjCCategoryDecl *Cat : OID->visible_categories())
-    if (ObjCMethodDecl *CatMeth =
-            Cat->getMethod(OMD->getSelector(), OMD->isInstanceMethod()))
-      if (!CatMeth->hasAttr<AvailabilityAttr>())
-        return true;
-  return false;
-}
-
-AvailabilityResult
-Sema::ShouldDiagnoseAvailabilityOfDecl(NamedDecl *&D, std::string *Message) {
+std::pair<AvailabilityResult, const NamedDecl *>
+Sema::ShouldDiagnoseAvailabilityOfDecl(const NamedDecl *D,
+                                       std::string *Message) {
   AvailabilityResult Result = D->getAvailability(Message);
 
   // For typedefs, if the typedef declaration appears available look
@@ -121,45 +106,23 @@ Sema::ShouldDiagnoseAvailabilityOfDecl(NamedDecl *&D, std::string *Message) {
   }
 
   // Forward class declarations get their attributes from their definition.
-  if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
+  if (const ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(D)) {
     if (IDecl->getDefinition()) {
       D = IDecl->getDefinition();
       Result = D->getAvailability(Message);
     }
   }
 
-  if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(D))
+  if (const auto *ECD = dyn_cast<EnumConstantDecl>(D))
     if (Result == AR_Available) {
       const DeclContext *DC = ECD->getDeclContext();
-      if (const EnumDecl *TheEnumDecl = dyn_cast<EnumDecl>(DC))
+      if (const auto *TheEnumDecl = dyn_cast<EnumDecl>(DC)) {
         Result = TheEnumDecl->getAvailability(Message);
+        D = TheEnumDecl;
+      }
     }
 
-  if (Result == AR_NotYetIntroduced) {
-    // Don't do this for enums, they can't be redeclared.
-    if (isa<EnumConstantDecl>(D) || isa<EnumDecl>(D))
-      return AR_Available;
-
-    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;
-
-    return Warn ? AR_NotYetIntroduced : AR_Available;
-  }
-
-  return Result;
+  return {Result, D};
 }
 
 static void
@@ -167,32 +130,34 @@ DiagnoseAvailabilityOfDecl(Sema &S, NamedDecl *D, SourceLocation Loc,
                            const ObjCInterfaceDecl *UnknownObjCClass,
                            bool ObjCPropertyAccess) {
   std::string Message;
+  AvailabilityResult Result;
+  const NamedDecl* OffendingDecl;
   // See if this declaration is unavailable, deprecated, or partial.
-  if (AvailabilityResult Result =
-          S.ShouldDiagnoseAvailabilityOfDecl(D, &Message)) {
+  std::tie(Result, OffendingDecl) = S.ShouldDiagnoseAvailabilityOfDecl(D, &Message);
+  if (Result == AR_Available)
+    return;
 
-    if (Result == AR_NotYetIntroduced) {
-      if (S.getCurFunctionOrMethodDecl()) {
-        S.getEnclosingFunction()->HasPotentialAvailabilityViolations = true;
-        return;
-      } else if (S.getCurBlock() || S.getCurLambda()) {
-        S.getCurFunction()->HasPotentialAvailabilityViolations = true;
-        return;
-      }
+  if (Result == AR_NotYetIntroduced) {
+    if (S.getCurFunctionOrMethodDecl()) {
+      S.getEnclosingFunction()->HasPotentialAvailabilityViolations = true;
+      return;
+    } else if (S.getCurBlock() || S.getCurLambda()) {
+      S.getCurFunction()->HasPotentialAvailabilityViolations = true;
+      return;
     }
+  }
 
-    const ObjCPropertyDecl *ObjCPDecl = nullptr;
-    if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
-      if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
-        AvailabilityResult PDeclResult = PD->getAvailability(nullptr);
-        if (PDeclResult == Result)
-          ObjCPDecl = PD;
-      }
+  const ObjCPropertyDecl *ObjCPDecl = nullptr;
+  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
+    if (const ObjCPropertyDecl *PD = MD->findPropertyDecl()) {
+      AvailabilityResult PDeclResult = PD->getAvailability(nullptr);
+      if (PDeclResult == Result)
+        ObjCPDecl = PD;
     }
-
-    S.EmitAvailabilityWarning(Result, D, Message, Loc, UnknownObjCClass,
-                              ObjCPDecl, ObjCPropertyAccess);
   }
+
+  S.EmitAvailabilityWarning(Result, D, OffendingDecl, Message, Loc,
+                            UnknownObjCClass, ObjCPDecl, ObjCPropertyAccess);
 }
 
 /// \brief Emit a note explaining that this function is deleted.