Author: Shafik Yaghmour Date: 2023-05-08T11:14:33-07:00 New Revision: 96bc78631f16fe5ce2e7e6000b74d790b32f7a16
URL: https://github.com/llvm/llvm-project/commit/96bc78631f16fe5ce2e7e6000b74d790b32f7a16 DIFF: https://github.com/llvm/llvm-project/commit/96bc78631f16fe5ce2e7e6000b74d790b32f7a16.diff LOG: [Clang] Update warning on some designator initializer cases involving unions Currently when using designated initializers in C++ we have a few extension. Two extension which are dangerous involved assigning to multiple members of union which will likely be a mistake since unions can only have one active member. I have updated to be a warning by default. The second case if when we assign to multiple union members and one of the previous members had a non-trivial destructor, which could lead to leaking resources. This one is now an error by default. Fixes: https://github.com/llvm/llvm-project/issues/62156 Differential Revision: https://reviews.llvm.org/D149694 Added: Modified: clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaInit.cpp clang/test/SemaCXX/cxx2b-designated-initializers.cpp Removed: ################################################################################ diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index c36828fc05da2..1d30d6f2102a4 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -186,6 +186,8 @@ def warn_initializer_overrides : Warning< "this subobject">, InGroup<InitializerOverrides>; def ext_initializer_overrides : ExtWarn<warn_initializer_overrides.Summary>, InGroup<InitializerOverrides>, SFINAEFailure; +def ext_initializer_union_overrides : ExtWarn<warn_initializer_overrides.Summary>, + InGroup<InitializerOverrides>, DefaultError, SFINAEFailure; def err_initializer_overrides_destructed : Error< "initializer would partially override prior initialization of object of " "type %1 with non-trivial destruction">; diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp index d27cd6b64c62a..3db70223bb8ba 100644 --- a/clang/lib/Sema/SemaInit.cpp +++ b/clang/lib/Sema/SemaInit.cpp @@ -394,12 +394,15 @@ class InitListChecker { /// Diagnose that OldInit (or part thereof) has been overridden by NewInit. void diagnoseInitOverride(Expr *OldInit, SourceRange NewInitRange, + bool UnionOverride = false, bool FullyOverwritten = true) { // Overriding an initializer via a designator is valid with C99 designated // initializers, but ill-formed with C++20 designated initializers. - unsigned DiagID = SemaRef.getLangOpts().CPlusPlus - ? diag::ext_initializer_overrides - : diag::warn_initializer_overrides; + unsigned DiagID = + SemaRef.getLangOpts().CPlusPlus + ? (UnionOverride ? diag::ext_initializer_union_overrides + : diag::ext_initializer_overrides) + : diag::warn_initializer_overrides; if (InOverloadResolution && SemaRef.getLangOpts().CPlusPlus) { // In overload resolution, we have to strictly enforce the rules, and so @@ -2546,6 +2549,7 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity, // subobject [0].b. diagnoseInitOverride(ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()), + /*UnionOverride=*/false, /*FullyOverwritten=*/false); if (!VerifyOnly) { @@ -2691,7 +2695,10 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity, if (ExistingInit) { // We're about to throw away an initializer, emit warning. diagnoseInitOverride( - ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc())); + ExistingInit, SourceRange(D->getBeginLoc(), DIE->getEndLoc()), + /*UnionOverride=*/true, + /*FullyOverwritten=*/SemaRef.getLangOpts().CPlusPlus ? false + : true); } // remove existing initializer diff --git a/clang/test/SemaCXX/cxx2b-designated-initializers.cpp b/clang/test/SemaCXX/cxx2b-designated-initializers.cpp index 3774565513673..5588926f419a9 100644 --- a/clang/test/SemaCXX/cxx2b-designated-initializers.cpp +++ b/clang/test/SemaCXX/cxx2b-designated-initializers.cpp @@ -19,3 +19,27 @@ void g(void) { } } // end namespace PR61118 + +namespace GH62156 { +union U1 { + int x; + float y; +}; + +struct NonTrivial { + NonTrivial(); + ~NonTrivial(); +}; + +union U2 { + NonTrivial x; + float y; +}; + +void f() { + U1 u{.x=2, // expected-note {{previous initialization is here}} + .y=1}; // expected-error {{initializer partially overrides prior initialization of this subobject}} + new U2{.x = NonTrivial{}, // expected-note {{previous initialization is here}} + .y=1}; // expected-error {{initializer would partially override prior initialization of object of type 'NonTrivial' with non-trivial destruction}} +} +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
