This is the mail archive of the gcc-help@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: GCC produces slightly different .o files on two consecutive runs in certain conditions


Hi,

On Tue, Jan 29, 2019 at 12:27 PM Jonathan Wakely <jwakely.gcc@gmail.com>
wrote:

> On Tue, 29 Jan 2019 at 00:23, Shlomi Fish <shlomif@gmail.com> wrote:
> >
> > Hi!
> >
> > On Tue, Jan 29, 2019 at 1:50 AM Shlomi Fish <shlomif@gmail.com> wrote:
> >>
> >> Hi,
> >>
> >> On Tue, Jan 29, 2019 at 1:28 AM Jonathan Wakely <jwakely.gcc@gmail.com>
> wrote:
> >>>
> >>> On Mon, 28 Jan 2019 at 23:24, Shlomi Fish <shlomif@gmail.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
> well?
> >>
> >
> > After adding a hack of putting -frandom-seed=24 in the $CFLAGS, the
> problematic behaviour seems to be gone:
> >
> >
> https://github.com/shlomif/fc-solve/commit/836c3ed85c4d1ce5c2c700b93f284e6019f0c105
> >
> > Thanks!
>
> Great. If that fixed it presumably the differences were in unique
> identifiers used for things like unnamed namespaces and lambda
> expressions.
>

OK, thanks for your help.

-- 
Shlomi Fish http://www.shlomifish.org/

Buddha has the Chuck Norris nature.

Please reply to list if it's a mailing list post - http://shlom.in/reply .


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]