[Clang] Fix: Restore warning inadvertently removed by D126061.

Before D126061, Clang would warn about this code

```
struct X {
    [[deprecated]] struct Y {};
};
```

with the warning

    attribute 'deprecated' is ignored, place it after "struct" to apply attribute to type declaration

D126061 inadvertently caused this warning to no longer be emitted. This patch
restores the previous behavior.

The reason for the bug is that after D126061, C++11 attributes applied to a
member declaration are no longer placed in `DS.getAttributes()` but are instead
tracked in a separate list (`DeclAttrs`). In the case of a free-standing
decl-specifier-seq, we would simply ignore the contents of this list. Instead,
we now pass the list on to `Sema::ParsedFreeStandingDeclSpec()` so that it can
issue the appropriate warning.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D128499

clang/include/clang/Sema/Sema.h

@@ -3117,8 +3117,10 @@ class Sema final {
   void ActOnTranslationUnitScope(Scope *S);
 
   Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
+                                   const ParsedAttributesView &DeclAttrs,
                                    RecordDecl *&AnonRecord);
   Decl *ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
+                                   const ParsedAttributesView &DeclAttrs,
                                    MultiTemplateParamsArg TemplateParams,
                                    bool IsExplicitInstantiation,
                                    RecordDecl *&AnonRecord);

clang/lib/Parse/ParseDecl.cpp

@@ -1863,8 +1863,8 @@ Parser::DeclGroupPtrTy Parser::ParseSimpleDeclaration(
     DeclEnd = Tok.getLocation();
     if (RequireSemi) ConsumeToken();
     RecordDecl *AnonRecord = nullptr;
-    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(getCurScope(), AS_none,
-                                                       DS, AnonRecord);
+    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(
+        getCurScope(), AS_none, DS, ParsedAttributesView::none(), AnonRecord);
     DS.complete(TheDecl);
     if (AnonRecord) {
       Decl* decls[] = {AnonRecord, TheDecl};
@@ -4358,8 +4358,8 @@ void Parser::ParseStructDeclaration(
     // declarator list is omitted."
     ProhibitAttributes(Attrs);
     RecordDecl *AnonRecord = nullptr;
-    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(getCurScope(), AS_none,
-                                                       DS, AnonRecord);
+    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(
+        getCurScope(), AS_none, DS, ParsedAttributesView::none(), AnonRecord);
     assert(!AnonRecord && "Did not expect anonymous struct or union here");
     DS.complete(TheDecl);
     return;

clang/lib/Parse/ParseDeclCXX.cpp

@@ -2766,7 +2766,7 @@ Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS,
 
     RecordDecl *AnonRecord = nullptr;
     Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(
-        getCurScope(), AS, DS, TemplateParams, false, AnonRecord);
+        getCurScope(), AS, DS, DeclAttrs, TemplateParams, false, AnonRecord);
     DS.complete(TheDecl);
     if (AnonRecord) {
       Decl* decls[] = {AnonRecord, TheDecl};

clang/lib/Parse/ParseTemplate.cpp

@@ -231,7 +231,7 @@ Decl *Parser::ParseSingleDeclarationAfterTemplate(
     DeclEnd = ConsumeToken();
     RecordDecl *AnonRecord = nullptr;
     Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
-        getCurScope(), AS, DS,
+        getCurScope(), AS, DS, ParsedAttributesView::none(),
         TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
                                     : MultiTemplateParamsArg(),
         TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation,

clang/lib/Parse/Parser.cpp

@@ -1113,8 +1113,8 @@ Parser::DeclGroupPtrTy Parser::ParseDeclOrFunctionDefInternal(
     ProhibitAttributes(Attrs, CorrectLocationForAttributes);
     ConsumeToken();
     RecordDecl *AnonRecord = nullptr;
-    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(getCurScope(), AS_none,
-                                                       DS, AnonRecord);
+    Decl *TheDecl = Actions.ParsedFreeStandingDeclSpec(
+        getCurScope(), AS_none, DS, ParsedAttributesView::none(), AnonRecord);
     DS.complete(TheDecl);
     if (AnonRecord) {
       Decl* decls[] = {AnonRecord, TheDecl};

clang/lib/Sema/SemaDecl.cpp

@@ -4629,11 +4629,12 @@ bool Sema::checkVarDeclRedefinition(VarDecl *Old, VarDecl *New) {
 
 /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
 /// no declarator (e.g. "struct foo;") is parsed.
-Decl *
-Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
-                                 RecordDecl *&AnonRecord) {
-  return ParsedFreeStandingDeclSpec(S, AS, DS, MultiTemplateParamsArg(), false,
-                                    AnonRecord);
+Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
+                                       DeclSpec &DS,
+                                       const ParsedAttributesView &DeclAttrs,
+                                       RecordDecl *&AnonRecord) {
+  return ParsedFreeStandingDeclSpec(
+      S, AS, DS, DeclAttrs, MultiTemplateParamsArg(), false, AnonRecord);
 }
 
 // The MS ABI changed between VS2013 and VS2015 with regard to numbers used to
@@ -4846,11 +4847,12 @@ static unsigned GetDiagnosticTypeSpecifierID(DeclSpec::TST T) {
 /// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
 /// no declarator (e.g. "struct foo;") is parsed. It also accepts template
 /// parameters to cope with template friend declarations.
-Decl *
-Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
-                                 MultiTemplateParamsArg TemplateParams,
-                                 bool IsExplicitInstantiation,
-                                 RecordDecl *&AnonRecord) {
+Decl *Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS,
+                                       DeclSpec &DS,
+                                       const ParsedAttributesView &DeclAttrs,
+                                       MultiTemplateParamsArg TemplateParams,
+                                       bool IsExplicitInstantiation,
+                                       RecordDecl *&AnonRecord) {
   Decl *TagD = nullptr;
   TagDecl *Tag = nullptr;
   if (DS.getTypeSpecType() == DeclSpec::TST_class ||
@@ -5089,7 +5091,7 @@ Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
   // Warn about ignored type attributes, for example:
   // __attribute__((aligned)) struct A;
   // Attributes should be placed after tag to apply to type declaration.
-  if (!DS.getAttributes().empty()) {
+  if (!DS.getAttributes().empty() || !DeclAttrs.empty()) {
     DeclSpec::TST TypeSpecType = DS.getTypeSpecType();
     if (TypeSpecType == DeclSpec::TST_class ||
         TypeSpecType == DeclSpec::TST_struct ||
@@ -5099,6 +5101,9 @@ Sema::ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS,
       for (const ParsedAttr &AL : DS.getAttributes())
         Diag(AL.getLoc(), diag::warn_declspec_attribute_ignored)
             << AL << GetDiagnosticTypeSpecifierID(TypeSpecType);
+      for (const ParsedAttr &AL : DeclAttrs)
+        Diag(AL.getLoc(), diag::warn_declspec_attribute_ignored)
+            << AL << GetDiagnosticTypeSpecifierID(TypeSpecType);
     }
   }
 

clang/test/SemaCXX/attr-declspec-ignored.cpp

@@ -6,14 +6,50 @@ namespace test1 {
   __attribute__((visibility("hidden")))  __attribute__((aligned)) struct B; // expected-warning{{attribute 'visibility' is ignored, place it after "struct" to apply attribute to type declaration}} \
   // expected-warning{{attribute 'aligned' is ignored, place it after "struct" to apply attribute to type declaration}}
   __attribute__((visibility("hidden")))  __attribute__((aligned)) union C; // expected-warning{{attribute 'visibility' is ignored, place it after "union" to apply attribute to type declaration}} \
-  // expected-warning{{attribute 'aligned' is ignored, place it after "union" to apply attribute to type declaration}} 
+  // expected-warning{{attribute 'aligned' is ignored, place it after "union" to apply attribute to type declaration}}
   __attribute__((visibility("hidden")))  __attribute__((aligned)) enum D {D}; // expected-warning{{attribute 'visibility' is ignored, place it after "enum" to apply attribute to type declaration}} \
   // expected-warning{{attribute 'aligned' is ignored, place it after "enum" to apply attribute to type declaration}}
+
+  // Test that we get the same warnings for type declarations nested in a record.
+  struct X {
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) class A; // expected-warning{{attribute 'visibility' is ignored, place it after "class" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "class" to apply attribute to type declaration}}
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) struct B; // expected-warning{{attribute 'visibility' is ignored, place it after "struct" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "struct" to apply attribute to type declaration}}
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) union C; // expected-warning{{attribute 'visibility' is ignored, place it after "union" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "union" to apply attribute to type declaration}}
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) enum D {D}; // expected-warning{{attribute 'visibility' is ignored, place it after "enum" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "enum" to apply attribute to type declaration}}
+
+    // Also test [[]] attribute syntax. (On a non-nested declaration, these
+    // generate a hard "misplaced attributes" error, which we test for
+    // elsewhere.)
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] class E; // expected-warning{{attribute 'visibility' is ignored, place it after "class" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "class" to apply attribute to type declaration}}
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] struct F; // expected-warning{{attribute 'visibility' is ignored, place it after "struct" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "struct" to apply attribute to type declaration}}
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] union G; // expected-warning{{attribute 'visibility' is ignored, place it after "union" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "union" to apply attribute to type declaration}}
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] enum H {H}; // expected-warning{{attribute 'visibility' is ignored, place it after "enum" to apply attribute to type declaration}} \
+    // expected-warning{{attribute 'aligned' is ignored, place it after "enum" to apply attribute to type declaration}}
+  };
 }
 
 namespace test2 {
   __attribute__((visibility("hidden")))  __attribute__((aligned)) class A {} a;
   __attribute__((visibility("hidden")))  __attribute__((aligned)) struct B {} b;
   __attribute__((visibility("hidden")))  __attribute__((aligned)) union C {} c;
   __attribute__((visibility("hidden")))  __attribute__((aligned)) enum D {D} d;
+
+  struct X {
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) class A {} a;
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) struct B {} b;
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) union C {} c;
+    __attribute__((visibility("hidden")))  __attribute__((aligned)) enum D {D} d;
+
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] class E {} e;
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] struct F {} f;
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] union G {} g;
+    [[gnu::visibility("hidden")]]  [[gnu::aligned]] enum H {H} h;
+  };
 }