On 8/6/21 1:33 AM, Richard Purdie wrote: > On Thu, 2021-08-05 at 17:54 -0400, Tony Battersby wrote: >> On 8/5/21 6:21 AM, Richard Purdie wrote: >>> On Wed, 2021-08-04 at 20:13 -0400, Randy MacLeod wrote: >>>> On 2021-07-27 9:34 a.m., Tony Battersby wrote: >>>>> Currently, enabling Link Time Optimization via: >>>>> >>>>> require conf/distro/include/lto.inc >>>>> DISTRO_FEATURES_append = " lto" >>>>> >>>>> makes the build non-reproducible (as in >>>>> https://reproducible-builds.org/). This patch set fixes some of the >>>>> problems, but is not yet a complete solution. >>>>> >>>>> This patch set addresses the following bugs: >>>>> https://bugzilla.yoctoproject.org/show_bug.cgi?id=14481 >>>>> https://bugzilla.yoctoproject.org/show_bug.cgi?id=14490 >>>>> >>>>> openembedded-core patches >>>>> 1/4: lto.inc: disable LTO for grub >>>>> 2/4: gcc: Backport patch to make LTO builds more reproducible >>>>> 3/4: bitbake.conf: add DEBUG_PREFIX_MAP to TARGET_LDFLAGS >>>>> >>>>> openembedded-devel patches >>>>> 4/4: net-snmp: fix QA Issue after LDFLAGS change >>>>> >>>>> Patch 3 adds DEBUG_PREFIX_MAP to TARGET_LDFLAGS (it was already in >>>>> TARGET_CFLAGS). This could possibly be done differently, such as by >>>>> removing it from TARGET_CFLAGS and adding it to TOOLCHAIN_OPTIONS, >>>>> TARGET_CC_ARCH, or TUNE_CCARGS, but I haven't tested those. Let me know >>>>> if there is a better/preferred way to do it. >>>>> >>>>> The TARGET_LDFLAGS change broke net-snmp from meta-networking, so I have >>>>> included a patch to fix that. Other packages might have been broken as >>>>> well, although I haven't found any others. >>>>> >>>>> With all these patches, there are still many shared libraries in /lib >>>>> and /usr/lib that are still not reproducible with LTO enabled because >>>>> x86_64-poky-linux-libtool filters out the -f*-prefix-map flags added by >>>>> patch 3 when linking shared libraries. /usr/lib/libbz2.so.1.0.6 from >>>>> the libbz2 package from the bzip2 recipe is a good example. I do not >>>>> have a patch for that problem. I will leave that to someone else. >>>>> >>>>> So this is what we need to achieve reproducible LTO builds: >>>>> *) This patch set >>>>> *) A fix for libtool >>>>> *) Add LTO to reproducible builds testing if appropriate (e.g. >>>>> meta/lib/oeqa/selftest/cases/reproducible.py, CI on Autobuilder) >>>>> *) Fixes for individual packages, if needed >>>>> *) Once everything works, update the documentation again (I previously >>>>> requested a documentation change for this bug, which will eventually >>>>> show up at >>>>> http://docs.yoctoproject.org/test-manual/reproducible-builds.html). >>>> This is certainly a few steps in the right direction with a good outline >>>> of what's next. >>>> >>>> I suspect that Richard has been busy with other things like overrides >>>> and the update to glibc-2.34. >>>> >>>> Do you have any suggestions or questions about what we should do >>>> with this patch series Richard? >>> Thanks for the reminder, I've been meaning to queue/test this which I will >>> do. The gcc version has been bumped but I ported the patch forward to it >>> and the patches are in master-next for testing. It is great to see this >>> support moving forward. >>> >>> Much as it pains me to admit having any libtool knowledge, I may be able to >>> help with that bit. There is an untested patch below which may address that >>> issue, or at least give a good hint on how to do it if it doesn't work. I >>> don't have an environment to test easily right now. >>> >>> Cheers, >>> >>> Richard >> I tested your libtool patch in master-next with the bzip2 recipe. It >> works as intended; libbz2.so.1.0.6 and all the other output files are >> now reproducible with LTO enabled. I also verified that libtool is >> passing the -f*-prefix-map flags to the link command in log.do_compile >> as intended. >> >> I also verified that core-image-minimal builds successfully with the >> libtool patch. > Thanks for testing that, sounds like it helps that issue. I'll queue that > patch. > > Unfortunately even with the ruby fix I queued, we still see reproduciblity > issues with the LDFLAGS change in curl-dev, gettext-ptest, ruby and ruby-dbg > packages: > > https://autobuilder.yoctoproject.org/typhoon/#/builders/115/builds/515/steps/12/logs/stdio > > We'll need to resolve those before I can merge the flags change. > > Diffoscope output: > > https://autobuilder.yocto.io/pub/repro-fail/oe-reproducible-20210805-8jfd55ki/packages/diff-html/ > > Basically LDFLAGS get encoded into a couple of scripts and the ruby binary. > > Cheers, > > Richard > It looks like the ruby problem is being caused by MJIT_DLDFLAGS in build/tmp/work/core2-64-poky-linux/ruby/3.0.2-r0/build/mjit_config.h. There is already a patch poky/meta/recipes-devtools/ruby/ruby/0001-template-Makefile.in-do-not-write-host-cross-cc-item.patch that removes some of these items for the sake of reproducibiltiy. But I do not know ruby, so I do not know the implications of doing the same thing for MJIT_DLDFLAGS.
Tony Battersby
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