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Re: GCC produces slightly different .o files on two consecutive runs in certain conditions
- From: Shlomi Fish <shlomif at gmail dot com>
- To: Jonathan Wakely <jwakely dot gcc at gmail dot com>
- Cc: gcc-help <gcc-help at gcc dot gnu dot org>
- Date: Tue, 29 Jan 2019 15:04:33 +0200
- Subject: Re: GCC produces slightly different .o files on two consecutive runs in certain conditions
- References: <CANy4znUBRzVUnyu93DqLEde+Sxvo8Pft11REZeoTWu3=9Gwuog@mail.gmail.com> <CAH6eHdQD+-Gv_Vm47eNdHOxit9N76mekRV2NKyy8dQZ7RYuwBw@mail.gmail.com> <CANy4znUde6_3+gJ33TVbWZmtFdYn1XMay=cSm5gp-62FmJJg+Q@mail.gmail.com> <CANy4znW=4xBdJOH3sEM1dtFd_WsQk3GBN4yiTMK-_z+_wcC_tg@mail.gmail.com> <CAH6eHdQVqMSCs-N=F6FuOa2k2WEd2N_k5hCWzx0wqtprPbVHhg@mail.gmail.com>
On Tue, Jan 29, 2019 at 12:27 PM Jonathan Wakely <email@example.com>
> On Tue, 29 Jan 2019 at 00:23, Shlomi Fish <firstname.lastname@example.org> wrote:
> > Hi!
> > On Tue, Jan 29, 2019 at 1:50 AM Shlomi Fish <email@example.com> wrote:
> >> Hi,
> >> On Tue, Jan 29, 2019 at 1:28 AM Jonathan Wakely <firstname.lastname@example.org>
> >>> On Mon, 28 Jan 2019 at 23:24, Shlomi Fish <email@example.com> wrote:
> >>> >
> >>> > Hi all!
> >>> >
> >>> > I am trying to do a https://reproducible-builds.org/ setup in my C
> / gnu11
> >>> > / cmake based FOSS project so I can cache valgrind results. The
> project is
> >>> > https://fc-solve.shlomifish.org/ and it has a git repo at
> >>> > https://github.com/shlomif/fc-solve .
> >>> It's not clear from your mail if you're using some or all of GCC's
> >>> options that are relevant, -Wdate-time and -frandom-seed, and the env
> >>> var SOURCE_DATE_EPOCH.
> >> I am using -Wdate-time and -Werror and it also happens with export
> SOURCE_DATE_EPOCH="0" now that I tried it. Should I try -frandom-seed as
> > After adding a hack of putting -frandom-seed=24 in the $CFLAGS, the
> problematic behaviour seems to be gone:
> > Thanks!
> Great. If that fixed it presumably the differences were in unique
> identifiers used for things like unnamed namespaces and lambda
OK, thanks for your help.
Shlomi Fish http://www.shlomifish.org/
Buddha has the Chuck Norris nature.
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