Re: ../../gdbsupport/new-op.cc:137:1: error: ‘void operator delete [](void*, std::size_t)’ is a usual (non-placement) deallocation function in C++14 (or with -fsized-deallocation) [-Werror=c++14-compat]

[Pedro Alves <pedro@palves.net>]

On 2022-03-02 16:54, Simon Marchi via Gdb-patches wrote:

> The story of this is that ASan gave some alloc-dealloc mismatch warnings
> if we didn't define these specific delete operators, so we defined them
> in this commit:
> 
>   https://gitlab.com/gnutools/binutils-gdb/-/commit/5fff6115feae7aaa23c0ae8d144e1c8418ee2ee1
> 
> But for the variants of delete that are only introduced in C++14, it
> meant adding functions without an equivalent declaration when building
> in C++11, which produced some -Wmissing-declarations warnings.  So these
> declarations were added in this commit:
> 
>   https://gitlab.com/gnutools/binutils-gdb/-/commit/b038b53f1ff4bf00ecdead1db23eddc4fd654305
> 
> The idea being that in C++11, these delete operators won't get used, but
> there will be a declaration to avoid the warning, and in C++14 the
> declarations will duplicate those found in headers, which is harmless.
> 
> And now here we are, we have a C++11 compiler that complains about
> declaring these delete operators.
> 
> So we can't simply remove the declarations and / or definitions, we
> would just re-introduce the problems fixed by these commits.
> 
> I think that a clean way to fix this would be to conditionally define
> these delete operators based on the C++ version.  So we would remove the
> declarations, as you do in your commit, but place the definitions under
> an "#if __cplusplus >= xyz".
> 

How can we be sure that some C++ library linked with gdb won't call them, though?
Like e.g., libsource-highlight.so.  It would seem to me that the best approach
would be to disable the warning around the declarations/definitions.