Re: [PATCH] lto-plugin: add support for feature detection

[Alexander Monakov <amonakov@ispras.ru>]

On Wed, 4 May 2022, Martin Liška wrote:

> The patch is a follow-up of the discussion we've got in:
> https://gcc.gnu.org/pipermail/gcc-patches/2022-May/593901.html
> 
> Mold linker would appreciate knowing in advance if get_symbols_v3 is supported
> by a GCC plug-in or not.
> 
> Ready to be installed?

Quick note: if the linker is supposed to check for presence of this symbol
via dlsym(), I expect it won't work as-is since lto-plugin.map hides every
symbol except 'onload'.

(also it might be nicer to reword the comment to say 'Presence of the following
symbols is used for ...', because you're leaving the value as 'false').

Alexander

> Thanks,
> Martin
> 
> lto-plugin/ChangeLog:
> 
> 	* lto-plugin.c (supports_get_symbols_v3): Add symbol.
> ---
>  lto-plugin/lto-plugin.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
> index 47378435612..049f3841d5b 100644
> --- a/lto-plugin/lto-plugin.c
> +++ b/lto-plugin/lto-plugin.c
> @@ -1554,3 +1554,8 @@ onload (struct ld_plugin_tv *tv)
>  
>    return LDPS_OK;
>  }
> +
> +/* The following symbols are used for dynamic detection of plug-in features
> +   from linker side.  */
> +
> +bool supports_get_symbols_v3;
>