llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Vlad Serebrennikov (Endilll) <details> <summary>Changes</summary> This patch implements (not yet published) [P3144R2](https://wiki.edg.com/pub/Wg21stlouis2024/StrawPolls/p3144r2.pdf) "Deleting a Pointer to an Incomplete Type Should be Ill-formed". Wording changes (not yet merged into the working draft) read: > 7.6.2.9 [expr.delete] Delete > If the object being deleted has incomplete class type at the point of deletion <del>and the complete class has a non-trivial destructor or a deallocation function, the behavior is undefined</del>, <ins>the program is ill-formed</ins>. We preserve status quo of emitting a warning when deleting a pointer to incomplete type up to, and including, C++23, but make it ill-formed since C++26. Same goes for deleting pointers to `void`, which has been allowed as an extension. --- Full diff: https://github.com/llvm/llvm-project/pull/97733.diff 4 Files Affected: - (modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+2) - (modified) clang/lib/Sema/SemaExprCXX.cpp (+9-3) - (modified) clang/test/CXX/drs/cwg5xx.cpp (+13-9) - (modified) clang/test/SemaCXX/new-delete.cpp (+17-9) ``````````diff diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 3df64b2ecef1b..5c3e311ac6382 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -7991,6 +7991,8 @@ def err_ambiguous_delete_operand : Error< def warn_delete_incomplete : Warning< "deleting pointer to incomplete type %0 may cause undefined behavior">, InGroup<DeleteIncomplete>; +def err_delete_incomplete : Error< + "cannot delete pointer to incomplete type %0">; def err_delete_incomplete_class_type : Error< "deleting incomplete class type %0; no conversions to pointer type">; def err_delete_explicit_conversion : Error< diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp index 69074f92a0286..fcf2189a308a8 100644 --- a/clang/lib/Sema/SemaExprCXX.cpp +++ b/clang/lib/Sema/SemaExprCXX.cpp @@ -3719,8 +3719,11 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal, // The C++ standard bans deleting a pointer to a non-object type, which // effectively bans deletion of "void*". However, most compilers support // this, so we treat it as a warning unless we're in a SFINAE context. - Diag(StartLoc, diag::ext_delete_void_ptr_operand) - << Type << Ex.get()->getSourceRange(); + // But we still prohibit this since C++26. + Diag(StartLoc, LangOpts.CPlusPlus26 ? diag::err_delete_incomplete + : diag::ext_delete_void_ptr_operand) + << (LangOpts.CPlusPlus26 ? Pointee : Type) + << Ex.get()->getSourceRange(); } else if (Pointee->isFunctionType() || Pointee->isVoidType() || Pointee->isSizelessType()) { return ExprError(Diag(StartLoc, diag::err_delete_operand) @@ -3729,7 +3732,10 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal, // FIXME: This can result in errors if the definition was imported from a // module but is hidden. if (!RequireCompleteType(StartLoc, Pointee, - diag::warn_delete_incomplete, Ex.get())) { + LangOpts.CPlusPlus26 + ? diag::err_delete_incomplete + : diag::warn_delete_incomplete, + Ex.get())) { if (const RecordType *RT = PointeeElem->getAs<RecordType>()) PointeeRD = cast<CXXRecordDecl>(RT->getDecl()); } diff --git a/clang/test/CXX/drs/cwg5xx.cpp b/clang/test/CXX/drs/cwg5xx.cpp index 9d890f981348a..6a0bb7a196669 100644 --- a/clang/test/CXX/drs/cwg5xx.cpp +++ b/clang/test/CXX/drs/cwg5xx.cpp @@ -1,9 +1,10 @@ -// RUN: %clang_cc1 -std=c++98 %s -verify=expected,cxx98-11,cxx98-14,cxx98-17,cxx98 -fexceptions -fcxx-exceptions -pedantic-errors -// RUN: %clang_cc1 -std=c++11 %s -verify=expected,cxx98-11,cxx98-14,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors -// RUN: %clang_cc1 -std=c++14 %s -verify=expected,cxx98-14,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors -// RUN: %clang_cc1 -std=c++17 %s -verify=expected,since-cxx17,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors -// RUN: %clang_cc1 -std=c++20 %s -verify=expected,since-cxx20,since-cxx17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors -// RUN: %clang_cc1 -std=c++23 %s -verify=expected,since-cxx23,since-cxx20,since-cxx17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++98 %s -verify=expected,cxx98-23,cxx98-11,cxx98-14,cxx98-17,cxx98 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++11 %s -verify=expected,cxx98-23,cxx98-11,cxx98-14,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++14 %s -verify=expected,cxx98-23,cxx98-14,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++17 %s -verify=expected,cxx98-23,since-cxx17,cxx98-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++20 %s -verify=expected,cxx98-23,since-cxx20,since-cxx17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++23 %s -verify=expected,cxx98-23,since-cxx23,since-cxx20,since-cxx17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors +// RUN: %clang_cc1 -std=c++2c %s -verify=expected,since-cxx26,since-cxx23,since-cxx20,since-cxx17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors #if __cplusplus == 199711L #define static_assert(...) __extension__ _Static_assert(__VA_ARGS__) @@ -901,7 +902,8 @@ namespace cwg573 { // cwg573: no void *d = reinterpret_cast<void*>(c); // cxx98-error@-1 {{cast between pointer-to-function and pointer-to-object is an extension}} void f() { delete a; } - // expected-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // cxx98-23-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // since-cxx26-error@-2 {{cannot delete pointer to incomplete type 'void'}} int n = d - a; // expected-error@-1 {{arithmetic on pointers to void}} // FIXME: This is ill-formed. @@ -1238,11 +1240,13 @@ namespace cwg599 { // cwg599: partial struct V { operator int*(); operator Fn*(); }; void f(void *p, void (*q)(), S s, T t, U u, V v) { delete p; - // expected-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // cxx98-23-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // since-cxx26-error@-2 {{cannot delete pointer to incomplete type 'void'}} delete q; // expected-error@-1 {{cannot delete expression of type 'void (*)()'}} delete s; - // expected-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // cxx98-23-error@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // since-cxx26-error@-2 {{cannot delete pointer to incomplete type 'void'}} delete t; // expected-error@-1 {{cannot delete expression of type 'T'}} // FIXME: This is valid, but is rejected due to a non-conforming GNU diff --git a/clang/test/SemaCXX/new-delete.cpp b/clang/test/SemaCXX/new-delete.cpp index 1a99c6aac604f..ec6ad43476f94 100644 --- a/clang/test/SemaCXX/new-delete.cpp +++ b/clang/test/SemaCXX/new-delete.cpp @@ -1,8 +1,10 @@ -// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++98 -// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11 -// RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14 -// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++17 -// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17,cxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++20 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++98 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++11 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++14 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,cxx17,precxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++17 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,cxx17,cxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++20 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx98-23,cxx17,cxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++23 +// RUN: %clang_cc1 -fsyntax-only -verify=expected,since-cxx26,cxx17,cxx20 %s -triple=i686-pc-linux-gnu -Wno-new-returns-null -std=c++2c // FIXME Location is (frontend) // cxx17-note@*:* {{candidate function not viable: requires 2 arguments, but 3 were provided}} @@ -172,8 +174,12 @@ void bad_deletes() { delete 0; // expected-error {{cannot delete expression of type 'int'}} delete [0] (int*)0; // expected-error {{expected variable name or 'this' in lambda capture list}} - delete (void*)0; // expected-warning {{cannot delete expression with pointer-to-'void' type 'void *'}} - delete (T*)0; // expected-warning {{deleting pointer to incomplete type}} + delete (void*)0; + // cxx98-23-warning@-1 {{cannot delete expression with pointer-to-'void' type 'void *'}} + // since-cxx26-error@-2 {{cannot delete pointer to incomplete type 'void'}} + delete (T*)0; + // cxx98-23-warning@-1 {{deleting pointer to incomplete type}} + // since-cxx26-error@-2 {{cannot delete pointer to incomplete type 'T'}} ::S::delete (int*)0; // expected-error {{expected unqualified-id}} } @@ -513,8 +519,10 @@ namespace DeleteIncompleteClass { namespace DeleteIncompleteClassPointerError { struct A; // expected-note {{forward declaration}} - void f(A *x) { 1+delete x; } // expected-warning {{deleting pointer to incomplete type}} \ - // expected-error {{invalid operands to binary expression}} + void f(A *x) { 1+delete x; } + // expected-error@-1 {{invalid operands to binary expression}} + // cxx98-23-warning@-2 {{deleting pointer to incomplete type}} + // since-cxx26-error@-3 {{cannot delete pointer to incomplete type 'A'}} } namespace PR10504 { `````````` </details> https://github.com/llvm/llvm-project/pull/97733 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
