[PATCH v3 1/2] Makefile: Allow LTO to be disabled for a build

Simon Glass sjg at chromium.org
Thu Sep 1 04:26:53 CEST 2022


Hi Tom,

On Wed, 3 Aug 2022 at 12:13, Simon Glass <sjg at chromium.org> wrote:
>
> LTO (Link-Time Optimisation) is an very useful feature which can
> significantly reduce the size of U-Boot binaries. So far it has been
> made available for selected ARM boards and sandbox.
>
> However, incremental builds are much slower when LTO is used. For example,
> an incremental build of sandbox takes 2.1 seconds on my machine, but 6.7
> seconds with LTO enabled.
>
> Add a NO_LTO parameter to the build, similar to NO_SDL, so it can be
> disabled during development if needed, for faster builds.
>
> Add some documentation about LTO while we are here.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v3:
> - Rework to operate like the NO_SDL flag
>
>  Makefile                           | 17 ++++++++++++-----
>  arch/arm/config.mk                 |  4 ++--
>  arch/arm/include/asm/global_data.h |  2 +-
>  doc/build/gcc.rst                  | 17 +++++++++++++++++
>  scripts/Makefile.spl               |  2 +-
>  5 files changed, 33 insertions(+), 9 deletions(-)

Any word on this patch and the next one, please?

Regards,
Simon


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