https://github.com/bricknerb updated https://github.com/llvm/llvm-project/pull/111856
>From 786d31e2657964e578cd1fdf2006b0fb3b19fab6 Mon Sep 17 00:00:00 2001 From: Boaz Brickner <brick...@google.com> Date: Thu, 10 Oct 2024 15:15:23 +0000 Subject: [PATCH 1/5] [clang] When checking for covariant return types, make sure the pointers or references are to *classes*. https://eel.is/c++draft/class.virtual#8.1 This prevents overriding methods with non class return types that have less cv-qualification. --- clang/lib/Sema/SemaDeclCXX.cpp | 4 ++-- clang/test/SemaCXX/virtual-override.cpp | 10 ++++++++++ 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index 9cb2ed02a3f764..6195b62b8afa16 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -18273,7 +18273,7 @@ bool Sema::CheckOverridingFunctionReturnType(const CXXMethodDecl *New, } // The return types aren't either both pointers or references to a class type. - if (NewClassTy.isNull()) { + if (NewClassTy.isNull() || !NewClassTy->isStructureOrClassType()) { Diag(New->getLocation(), diag::err_different_return_type_for_overriding_virtual_function) << New->getDeclName() << NewTy << OldTy @@ -18296,7 +18296,7 @@ bool Sema::CheckOverridingFunctionReturnType(const CXXMethodDecl *New, diag::err_covariant_return_incomplete, New->getDeclName())) return true; - } + } // Check if the new class derives from the old class. if (!IsDerivedFrom(New->getLocation(), NewClassTy, OldClassTy)) { diff --git a/clang/test/SemaCXX/virtual-override.cpp b/clang/test/SemaCXX/virtual-override.cpp index 72abfc3cf51e1f..6008b8ed063f20 100644 --- a/clang/test/SemaCXX/virtual-override.cpp +++ b/clang/test/SemaCXX/virtual-override.cpp @@ -289,3 +289,13 @@ namespace PR8168 { static void foo() {} // expected-error{{'static' member function 'foo' overrides a virtual function}} }; } + +namespace T13 { + struct A { + virtual const int *f() const; // expected-note{{overridden virtual function is here}} + }; + + struct B : A { + int *f() const override; // expected-error{{virtual function 'f' has a different return type ('int *') than the function it overrides (which has return type 'const int *')}} + }; +} >From 027a985f2ca2bbe007db751af4fdbb5d8f12959d Mon Sep 17 00:00:00 2001 From: Boaz Brickner <brick...@google.com> Date: Fri, 11 Oct 2024 05:29:05 +0000 Subject: [PATCH 2/5] Fix indentation. --- clang/lib/Sema/SemaDeclCXX.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index 6195b62b8afa16..75d010dc4e04d8 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -18296,7 +18296,7 @@ bool Sema::CheckOverridingFunctionReturnType(const CXXMethodDecl *New, diag::err_covariant_return_incomplete, New->getDeclName())) return true; - } + } // Check if the new class derives from the old class. if (!IsDerivedFrom(New->getLocation(), NewClassTy, OldClassTy)) { >From 0b0452f3b7206fdea595aff684c329fd4563f631 Mon Sep 17 00:00:00 2001 From: Boaz Brickner <brick...@google.com> Date: Fri, 11 Oct 2024 12:27:00 +0000 Subject: [PATCH 3/5] [clang] Add the breaking change to more correctly check covariance when return type doesn't point to a class to release notes. --- clang/docs/ReleaseNotes.rst | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index df165b91252505..55ca61955c5b01 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -99,6 +99,19 @@ C++ Specific Potentially Breaking Changes // Was error, now evaluates to false. constexpr bool b = f() == g(); +- Clang will now correctly not consider pointers to non classes for covariance. + + .. code-block:: c++ + + struct A { + virtual const int *f() const; + }; + struct B : A { + // Return type has less cv-qualification but doesn't point to a class. + // Error will be generated. + int *f() const override; + }; + ABI Changes in This Version --------------------------- >From d5cf39d317ea2474477382f6dfa3a116c7db67f8 Mon Sep 17 00:00:00 2001 From: Boaz Brickner <brick...@google.com> Date: Fri, 11 Oct 2024 13:38:39 +0000 Subject: [PATCH 4/5] [clang] Fix code indentation in release notes for fixing how we handle pointers to non classes when calculating covariance. --- clang/docs/ReleaseNotes.rst | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 55ca61955c5b01..3ae716859fdcdf 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -103,14 +103,14 @@ C++ Specific Potentially Breaking Changes .. code-block:: c++ - struct A { - virtual const int *f() const; - }; - struct B : A { - // Return type has less cv-qualification but doesn't point to a class. - // Error will be generated. - int *f() const override; - }; + struct A { + virtual const int *f() const; + }; + struct B : A { + // Return type has less cv-qualification but doesn't point to a class. + // Error will be generated. + int *f() const override; + }; ABI Changes in This Version --------------------------- >From 44d5ebec41cc754ad9063d30bcb916a213e16006 Mon Sep 17 00:00:00 2001 From: Boaz Brickner <brick...@google.com> Date: Mon, 14 Oct 2024 14:19:30 +0000 Subject: [PATCH 5/5] [clang] Unify the new covariant tests, remove T13 and add the new tests into T2 and T6. In T2, we check that return types that are pointers to different non-class types fail. In T6, we check that unlike class return types, non-class return types do not allow to change qualifiers at all (add or remove). --- clang/test/SemaCXX/virtual-override.cpp | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/clang/test/SemaCXX/virtual-override.cpp b/clang/test/SemaCXX/virtual-override.cpp index 6008b8ed063f20..d37c275d46baeb 100644 --- a/clang/test/SemaCXX/virtual-override.cpp +++ b/clang/test/SemaCXX/virtual-override.cpp @@ -19,10 +19,12 @@ struct b { }; class A { virtual a* f(); // expected-note{{overridden virtual function is here}} + virtual int *g(); // expected-note{{overridden virtual function is here}} }; class B : A { virtual b* f(); // expected-error{{return type of virtual function 'f' is not covariant with the return type of the function it overrides ('b *' is not derived from 'a *')}} + virtual char *g(); // expected-error{{virtual function 'g' has a different return type ('char *') than the function it overrides (which has return type 'int *')}} }; } @@ -83,11 +85,15 @@ struct a { }; class A { virtual const a* f(); virtual a* g(); // expected-note{{overridden virtual function is here}} + virtual const int* h(); // expected-note{{overridden virtual function is here}} + virtual int* i(); // expected-note{{overridden virtual function is here}} }; class B : A { virtual a* f(); virtual const a* g(); // expected-error{{return type of virtual function 'g' is not covariant with the return type of the function it overrides (class type 'const a *' is more qualified than class type 'a *'}} + virtual int* h(); // expected-error{{virtual function 'h' has a different return type ('int *') than the function it overrides (which has return type 'const int *')}} + virtual const int* i(); // expected-error{{virtual function 'i' has a different return type ('const int *') than the function it overrides (which has return type 'int *')}} }; } @@ -289,13 +295,3 @@ namespace PR8168 { static void foo() {} // expected-error{{'static' member function 'foo' overrides a virtual function}} }; } - -namespace T13 { - struct A { - virtual const int *f() const; // expected-note{{overridden virtual function is here}} - }; - - struct B : A { - int *f() const override; // expected-error{{virtual function 'f' has a different return type ('int *') than the function it overrides (which has return type 'const int *')}} - }; -} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
