Re: [docs] [PATCH] test-manual: document LTO related reproducibility bug

Re: [docs] [PATCH] test-manual: document LTO related reproducibility bug

[Michael Opdenacker]

On 7/16/21 7:57 PM, Michael Opdenacker wrote:
> Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
> ---
>  documentation/test-manual/reproducible-builds.rst | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/documentation/test-manual/reproducible-builds.rst b/documentation/test-manual/reproducible-builds.rst
> index e13583c0bf..1938041b2d 100644
> --- a/documentation/test-manual/reproducible-builds.rst
> +++ b/documentation/test-manual/reproducible-builds.rst
> @@ -68,6 +68,17 @@ things we do within the build system to ensure reproducibility include:
>  -  Filtering the tools available from the host's ``PATH`` to only a specific set
>     of tools, set using the :term:`HOSTTOOLS` variable.
>  
> +.. note::
> +
> +   Because of an open bug in GCC, using ``DISTRO_FEATURES_append = " lto"`` or
> +   adding ``-flto`` (Link Time Optimization) to a Makefile makes the resulting
> +   binary non-reproducible, in that it depends on the full absolute build path
> +   to ``recipe-sysroot-native``, so installing the Yocto Project in a different
> +   directory results in a different binary.
> +
> +   This issue is addressed by
> +   :yocto_bugs:`bug 14481 -  Programs built with -flto are not reproducible</show_bug.cgi?id=14481>`.

Merged into "master-next" for yocto-docs, after replacing "a Makefile"
by "CFLAGS", as recommended by Tony (thanks!)

Cheers
Michael.

-- 
Michael Opdenacker, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com