[PATCH] D66711: [clang] Warning for non-final classes with final destructors

[Logan Smith via Phabricator via cfe-commits]

logan-5 updated this revision to Diff 217049.
logan-5 added a comment.

Addressed some feedback.


Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D66711/new/

https://reviews.llvm.org/D66711

Files:
  clang/include/clang/Basic/DiagnosticGroups.td
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/SemaCXX/MicrosoftExtensions.cpp
  clang/test/SemaCXX/warn-final-dtor-non-final-class.cpp


Index: clang/test/SemaCXX/warn-final-dtor-non-final-class.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/warn-final-dtor-non-final-class.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s -Wfinal-dtor-non-final-class
+
+class A {
+    ~A();
+};
+
+class B { // expected-note {{mark 'B' as 'final' to silence this warning}}
+    virtual ~B() final; // expected-warning {{class with destructor marked 'final' cannot be inherited from}}
+};
+
+class C final {
+    virtual ~C() final;
+};
Index: clang/test/SemaCXX/MicrosoftExtensions.cpp
===================================================================
--- clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -475,6 +475,11 @@
 // expected-error at +1 {{base 'SealedType' is marked 'sealed'}}
 struct InheritFromSealed : SealedType {};
 
+class SealedDestructor { // expected-note {{mark 'SealedDestructor' as 'sealed' to silence this warning}}
+    // expected-warning at +1 {{'sealed' keyword is a Microsoft extension}}
+    virtual ~SealedDestructor() sealed; // expected-warning {{class with destructor marked 'sealed' cannot be inherited from}}
+};
+
 void AfterClassBody() {
   // expected-warning at +1 {{attribute 'deprecated' is ignored, place it after "struct" to apply attribute to type declaration}}
   struct D {} __declspec(deprecated);
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -6236,6 +6236,19 @@
     }
   }
 
+  // Warn if the class has a final destructor but is not itself marked final.
+  if (!Record->hasAttr<FinalAttr>()) {
+    if (const CXXDestructorDecl *dtor = Record->getDestructor()) {
+      if (const FinalAttr *FA = dtor->getAttr<FinalAttr>()) {
+        Diag(FA->getLocation(), diag::warn_final_dtor_non_final_class)
+          << FA->isSpelledAsSealed();
+        Diag(Record->getLocation(), diag::note_final_dtor_non_final_class_silence)
+          << Context.getRecordType(Record)
+          << FA->isSpelledAsSealed();
+      }
+    }
+  }
+
   // See if trivial_abi has to be dropped.
   if (Record->hasAttr<TrivialABIAttr>())
     checkIllFormedTrivialABIStruct(*Record);
Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2201,6 +2201,11 @@
   "base %0 is marked '%select{final|sealed}1'">;
 def warn_abstract_final_class : Warning<
   "abstract class is marked '%select{final|sealed}0'">, InGroup<AbstractFinalClass>;
+def warn_final_dtor_non_final_class : Warning<
+  "class with destructor marked '%select{final|sealed}0' cannot be inherited from">,
+  InGroup<FinalDtorNonFinalClass>;
+def note_final_dtor_non_final_class_silence : Note<
+  "mark %0 as '%select{final|sealed}1' to silence this warning">;
 
 // C++11 attributes
 def err_repeat_attribute : Error<"%0 attribute cannot be repeated">;
Index: clang/include/clang/Basic/DiagnosticGroups.td
===================================================================
--- clang/include/clang/Basic/DiagnosticGroups.td
+++ clang/include/clang/Basic/DiagnosticGroups.td
@@ -114,6 +114,7 @@
                                      [DeleteNonAbstractNonVirtualDtor,
                                       DeleteAbstractNonVirtualDtor]>;
 def AbstractFinalClass : DiagGroup<"abstract-final-class">;
+def FinalDtorNonFinalClass : DiagGroup<"final-dtor-non-final-class">;
 
 def CXX11CompatDeprecatedWritableStr :
   DiagGroup<"c++11-compat-deprecated-writable-strings">;


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