https://github.com/AaronBallman created
https://github.com/llvm/llvm-project/pull/118800
When a destroying delete overload is selected, the destructor is not
automatically called. Therefore, the destructor can be deleted without causing
the program to be ill-formed.
>From 34d3d3000bc6096bbc9eb35ce85b6ceca50b91ca Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aa...@aaronballman.com>
Date: Thu, 5 Dec 2024 08:31:24 -0500
Subject: [PATCH] [C++20] Destroying delete and deleted destructors
When a destroying delete overload is selected, the destructor is not
automatically called. Therefore, the destructor can be deleted without
causing the program to be ill-formed.
---
clang/docs/ReleaseNotes.rst | 2 ++
clang/lib/Sema/SemaExprCXX.cpp | 6 +++--
.../CXX/expr/expr.unary/expr.delete/p10.cpp | 22 +++++++++++++++++--
3 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e484eb7a76e63a..4a72e4046e2d03 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -663,6 +663,8 @@ Bug Fixes in This Version
- Fixed a crash when GNU statement expression contains invalid statement
(#GH113468).
- Fixed a failed assertion when using ``__attribute__((noderef))`` on an
``_Atomic``-qualified type (#GH116124).
+- No longer incorrectly diagnosing use of a deleted destructor when the
+ selected overload of ``operator delete`` for that type is a destroying
delete.
Bug Fixes to Compiler Builtins
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index db9ea7fb66e05a..45840dfa31ac92 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -3792,13 +3792,15 @@ Sema::ActOnCXXDelete(SourceLocation StartLoc, bool
UseGlobal,
.HasSizeT;
}
- if (!PointeeRD->hasIrrelevantDestructor())
+ if (!PointeeRD->hasIrrelevantDestructor() &&
+ (!OperatorDelete || !OperatorDelete->isDestroyingOperatorDelete())) {
if (CXXDestructorDecl *Dtor = LookupDestructor(PointeeRD)) {
MarkFunctionReferenced(StartLoc,
- const_cast<CXXDestructorDecl*>(Dtor));
+ const_cast<CXXDestructorDecl *>(Dtor));
if (DiagnoseUseOfDecl(Dtor, StartLoc))
return ExprError();
}
+ }
CheckVirtualDtorCall(PointeeRD->getDestructor(), StartLoc,
/*IsDelete=*/true, /*CallCanBeVirtual=*/true,
diff --git a/clang/test/CXX/expr/expr.unary/expr.delete/p10.cpp
b/clang/test/CXX/expr/expr.unary/expr.delete/p10.cpp
index aad2747dd32f24..b2c0a2c79695fc 100644
--- a/clang/test/CXX/expr/expr.unary/expr.delete/p10.cpp
+++ b/clang/test/CXX/expr/expr.unary/expr.delete/p10.cpp
@@ -1,7 +1,14 @@
-// RUN: %clang_cc1 -std=c++1z -verify %s
+// RUN: %clang_cc1 -std=c++20 -verify %s
using size_t = decltype(sizeof(0));
-namespace std { enum class align_val_t : size_t {}; }
+namespace std {
+ enum class align_val_t : size_t {};
+ struct destroying_delete_t {
+ explicit destroying_delete_t() = default;
+ };
+
+ inline constexpr destroying_delete_t destroying_delete{};
+}
// Aligned version is preferred over unaligned version,
// unsized version is preferred over sized version.
@@ -23,3 +30,14 @@ struct alignas(Align) B {
};
void f(B<__STDCPP_DEFAULT_NEW_ALIGNMENT__> *p) { delete p; }
void f(B<__STDCPP_DEFAULT_NEW_ALIGNMENT__ * 2> *p) { delete p; } //
expected-error {{deleted}}
+
+// Ensure that a deleted destructor is acceptable when the selected overload
+// for operator delete is a destroying delete. See the comments in GH118660.
+struct S {
+ ~S() = delete;
+ void operator delete(S *, std::destroying_delete_t) noexcept {}
+};
+
+void foo(S *s) {
+ delete s; // Was rejected, is intended to be accepted.
+}
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