[PING][RFC][gdb] Fix build error in macroexp.c

[Tom de Vries <tdevries@suse.de>]

On 06/22/2018 09:14 AM, Tom de Vries wrote:
> Hi,
> 
> When doing a combined build with the gcc and binutils-gdb repos, I run into
> this build error in gdb:
> ...
> gdb/macroexp.c: \
>   In function ‘void get_next_token_for_substitution(macro_buffer*, \
>   macro_buffer*, char**, macro_buffer*, char**, int*, bool*)’:
> gdb/macroexp.c:925:17: error: \
>   implicitly-declared ‘constexpr macro_buffer& \
>   macro_buffer::operator=(const macro_buffer&)’ is deprecated \
>   [-Werror=deprecated-copy]
>        *token = *lookahead;
> ...
> 
> This patch fixes the build error by adding an explicit copy operator to the
> macro_buffer class.  I've added asserts to ensure that both the dest and src
> of the copy are shared, in other words, neither is owner of the text pointer.
> 
> I've run the gdb testsuite on x86_64-linux and the asserts did not trigger.
> 
> Any comments?
> 
> Thanks,
> - Tom
> 
> [gdb] Fix build error in macroexp.c
> 
> 2018-06-22  Tom de Vries  <tdevries@suse.de>
> 
> 	* macroexp.c (macro_buffer) <operator=>: New member function.
> 
> ---
>  gdb/macroexp.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/gdb/macroexp.c b/gdb/macroexp.c
> index 1fa37d2875..8b4dfb20b8 100644
> --- a/gdb/macroexp.c
> +++ b/gdb/macroexp.c
> @@ -112,6 +112,16 @@ struct macro_buffer
>      shared = true;
>    }
>  
> +  macro_buffer& operator=(const macro_buffer &src)
> +  {
> +    gdb_assert (src.shared);
> +    gdb_assert (shared);
> +    set_shared (src.text, src.len);
> +    last_token = src.last_token;
> +    is_identifier = src.is_identifier;
> +    return *this;
> +  }
> +
>    ~macro_buffer ()
>    {
>      if (! shared && size)
>