[PATCH] libstdc++: operator new/delete are transaction_safe

[Jonathan Wakely]

On Sat, 21 Sept 2024, 14:24 Jason Merrill, <jason@redhat.com> wrote:

> Tested x86_64-pc-linux-gnu, OK for trunk?
>

All those macros already make them cluttered so this doesn't make them any
more unreadable!
OK, thanks



> -- 8< --
>
> With the changes to #pragma system_header, g++.dg/tm/pr46270.C was
> failing because <new> didn't implement the N4514 change to [new.delete]
> that
> says "The library versions of the global allocation and deallocation
> functions are declared transaction_safe (8.3.5 dcl.fct)."  We already have
> the _GLIBCXX_TXN_SAFE macro, just need to add it.
>
> libstdc++-v3/ChangeLog:
>
>         * libsupc++/new: Add _GLIBCXX_TXN_SAFE.
> ---
>  libstdc++-v3/libsupc++/new | 56 ++++++++++++++++++++++++++------------
>  1 file changed, 38 insertions(+), 18 deletions(-)
>
> diff --git a/libstdc++-v3/libsupc++/new b/libstdc++-v3/libsupc++/new
> index 7e1eee8f9d6..e9a3d9b49a3 100644
> --- a/libstdc++-v3/libsupc++/new
> +++ b/libstdc++-v3/libsupc++/new
> @@ -134,49 +134,63 @@ namespace std
>   *  Placement new and delete signatures (take a memory address argument,
>   *  does nothing) may not be replaced by a user's program.
>  */
> -_GLIBCXX_NODISCARD void* operator new(std::size_t) _GLIBCXX_THROW
> (std::bad_alloc)
> +_GLIBCXX_NODISCARD void* operator new(std::size_t)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_THROW (std::bad_alloc)
>    __attribute__((__externally_visible__));
> -_GLIBCXX_NODISCARD void* operator new[](std::size_t) _GLIBCXX_THROW
> (std::bad_alloc)
> +_GLIBCXX_NODISCARD void* operator new[](std::size_t)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_THROW (std::bad_alloc)
>    __attribute__((__externally_visible__));
> -void operator delete(void*) _GLIBCXX_USE_NOEXCEPT
> +void operator delete(void*) _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
> -void operator delete[](void*) _GLIBCXX_USE_NOEXCEPT
> +void operator delete[](void*) _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
>  #if __cpp_sized_deallocation
> -void operator delete(void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
> +void operator delete(void*, std::size_t)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
> -void operator delete[](void*, std::size_t) _GLIBCXX_USE_NOEXCEPT
> +void operator delete[](void*, std::size_t)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
>  #endif
> -_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&)
> _GLIBCXX_USE_NOEXCEPT
> +_GLIBCXX_NODISCARD void* operator new(std::size_t, const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
> -_GLIBCXX_NODISCARD void* operator new[](std::size_t, const
> std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
> +_GLIBCXX_NODISCARD void* operator new[](std::size_t, const
> std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
> -void operator delete(void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
> +void operator delete(void*, const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
> -void operator delete[](void*, const std::nothrow_t&) _GLIBCXX_USE_NOEXCEPT
> +void operator delete[](void*, const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>    __attribute__((__externally_visible__));
>  #if __cpp_aligned_new
>  _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t)
> +  _GLIBCXX_TXN_SAFE
>    __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
>  _GLIBCXX_NODISCARD void* operator new(std::size_t, std::align_val_t,
> const std::nothrow_t&)
> +   _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__,
> __alloc_size__ (1), __malloc__));
> -void operator delete(void*, std::align_val_t)
> +void operator delete(void*, std::align_val_t) _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
>  void operator delete(void*, std::align_val_t, const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
>  _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t)
> +  _GLIBCXX_TXN_SAFE
>    __attribute__((__externally_visible__, __alloc_size__ (1), __malloc__));
>  _GLIBCXX_NODISCARD void* operator new[](std::size_t, std::align_val_t,
> const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__,
> __alloc_size__ (1), __malloc__));
> -void operator delete[](void*, std::align_val_t)
> +void operator delete[](void*, std::align_val_t) _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
>  void operator delete[](void*, std::align_val_t, const std::nothrow_t&)
> +  _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
>  #if __cpp_sized_deallocation
> -void operator delete(void*, std::size_t, std::align_val_t)
> +void operator delete(void*, std::size_t, std::align_val_t)
> _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
> -void operator delete[](void*, std::size_t, std::align_val_t)
> +void operator delete[](void*, std::size_t, std::align_val_t)
> _GLIBCXX_TXN_SAFE
>    _GLIBCXX_USE_NOEXCEPT __attribute__((__externally_visible__));
>  #endif // __cpp_sized_deallocation
>  #endif // __cpp_aligned_new
> @@ -189,17 +203,23 @@ void operator delete[](void*, std::size_t,
> std::align_val_t)
>
>  // Default placement versions of operator new.
>  _GLIBCXX_NODISCARD _GLIBCXX_PLACEMENT_CONSTEXPR
> -void* operator new(std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
> +void* operator new(std::size_t, void* __p)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>  { return __p; }
>  _GLIBCXX_NODISCARD _GLIBCXX_PLACEMENT_CONSTEXPR
> -void* operator new[](std::size_t, void* __p) _GLIBCXX_USE_NOEXCEPT
> +void* operator new[](std::size_t, void* __p)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
>  { return __p; }
>
>  #undef _GLIBCXX_PLACEMENT_CONSTEXPR
>
>  // Default placement versions of operator delete.
> -inline void operator delete  (void*, void*) _GLIBCXX_USE_NOEXCEPT { }
> -inline void operator delete[](void*, void*) _GLIBCXX_USE_NOEXCEPT { }
> +inline void operator delete  (void*, void*)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
> +{ }
> +inline void operator delete[](void*, void*)
> +  _GLIBCXX_TXN_SAFE _GLIBCXX_USE_NOEXCEPT
> +{ }
>  //@}
>  } // extern "C++"
>
>
> base-commit: 2484ba167e1c4a52d4989b71e1f5d4d27755500f
> --
> 2.46.0
>
>
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