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| author | Jonathan Wakely <jwakely@redhat.com> | 2024-08-28 13:07:47 +0100 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2024-09-03 15:08:44 +0100 |
| commit | dee3c5c6ff9952204af3014383593e8d316250e4 (patch) | |
| tree | c2f28ebde72efea7cd0f59b3200ea76e99de209e | |
| parent | efe6efb6f315c7f97be8a850e0a84ff7f6651d85 (diff) | |
| download | gcc-dee3c5c6ff9952204af3014383593e8d316250e4.zip gcc-dee3c5c6ff9952204af3014383593e8d316250e4.tar.gz gcc-dee3c5c6ff9952204af3014383593e8d316250e4.tar.bz2 | |
libstdc++: Simplify std::any to fix -Wdeprecated-declarations warning
We don't need to use std::aligned_storage in std::any. We just need a
POD type of the right size. The void* union member already ensures the
alignment will be correct. Avoiding std::aligned_storage means we don't
need to suppress a -Wdeprecated-declarations warning.
libstdc++-v3/ChangeLog:
* include/experimental/any (experimental::any::_Storage): Use
array of unsigned char instead of deprecated
std::aligned_storage.
* include/std/any (any::_Storage): Likewise.
* testsuite/20_util/any/layout.cc: New test.
| -rw-r--r-- | libstdc++-v3/include/experimental/any | 2 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/any | 2 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/20_util/any/layout.cc | 22 |
3 files changed, 24 insertions, 2 deletions
diff --git a/libstdc++-v3/include/experimental/any b/libstdc++-v3/include/experimental/any index 27a7a14..3db30df 100644 --- a/libstdc++-v3/include/experimental/any +++ b/libstdc++-v3/include/experimental/any @@ -102,7 +102,7 @@ inline namespace fundamentals_v1 _Storage& operator=(const _Storage&) = delete; void* _M_ptr; - aligned_storage<sizeof(_M_ptr), alignof(void*)>::type _M_buffer; + unsigned char _M_buffer[sizeof(_M_ptr)]; }; template<typename _Tp, typename _Safe = is_nothrow_move_constructible<_Tp>, diff --git a/libstdc++-v3/include/std/any b/libstdc++-v3/include/std/any index e4709b1c..9ae29aa 100644 --- a/libstdc++-v3/include/std/any +++ b/libstdc++-v3/include/std/any @@ -90,7 +90,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION _Storage& operator=(const _Storage&) = delete; void* _M_ptr; - aligned_storage<sizeof(_M_ptr), alignof(void*)>::type _M_buffer; + unsigned char _M_buffer[sizeof(_M_ptr)]; }; template<typename _Tp, typename _Safe = is_nothrow_move_constructible<_Tp>, diff --git a/libstdc++-v3/testsuite/20_util/any/layout.cc b/libstdc++-v3/testsuite/20_util/any/layout.cc new file mode 100644 index 0000000..5a7f4a8 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/any/layout.cc @@ -0,0 +1,22 @@ +// { dg-options "-Wno-deprecated-declarations" } +// { dg-do compile { target c++17 } } + +// Verify that r15-3419 did not change the layout of std::any + +#include <any> + +namespace test { + class any { + union Storage { + constexpr Storage() : ptr(nullptr) { } + void* ptr; + std::aligned_storage<sizeof(ptr), alignof(void*)>::type buffer; + }; + + void (*manager)(int, const any*, void*); + Storage storage; + }; +} + +static_assert( sizeof(std::any) == sizeof(test::any) ); +static_assert( alignof(std::any) == alignof(test::any) ); |