[PATCH] tools/gnu: Enable LTO in RSB tools

[Chris Johns]

On 16/6/2022 8:41 am, Joel Sherrill wrote:
> On Wed, Jun 15, 2022 at 5:29 PM Chris Johns <chrisj at rtems.org
> <mailto:chrisj at rtems.org>> wrote:
> 
>     On 15/6/2022 10:58 pm, Joel Sherrill wrote:
>     > What's the problem with enabling LTO support in the tools by default?
> 
>     None that I know of and this patch enables the support by default. The RSB
>     incorrectly supported the configure `--enable-lto` option. That option controls
>     the host build and when enabled the built host executables are built with LTO.
> 
>     For RTEMS building LTO support is via the languages option, ie it is treated as
>     a language. This patch provides that support and enables it.
> 
> I'm happy with that. If it is going to cause a problem building the tools, it would
> be better to know it and then disable it for an architecture until that's resolved. 

Is that a catch-22? We will not know until we enable it? :)

>     > Using it is a different matter.
> 
>     Yes. I comments were an attempt to highlight this. I would like to see LTO
>     support available but it is not something all users will use.
> 
>     FYI Xilinx use to build the Microblaze firmware for the PMC/PMS cores in the
>     Versal.
> 
>  Interesting. I wonder if we have any examples that would show
> a real benefit from it. I think it would take a real application to 
> see an advantage.

I do not know. It should help with C++ applications.

Chris