I was thinking about this, and while I don't have the right compiler installed to try this myself, the solution might be to filter out the LTO option when doing the partial link like the -shared option. I *think* what will happen is that the sections with the GIMPLE (LTO data) will be merged, and then the LTO will still happen during the final link. I think what might be happening is that g++ is doing actual LTO during the partial links, and that's messing things up later since things which should only be done at the end have been done multiple times before then. This is largely speculation, but probably worth a try.
Gabe On Sat, May 27, 2017 at 2:41 PM, Alec Roelke <[email protected]> wrote: > Sorry for the late reply; I've been traveling. I did try this with a > clean build of a fresh clone of the repository, and got the error with both > RISC-V and x86. The version of GCC that I'm using is gcc (Ubuntu > 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609. > > On May 24, 2017 10:23 PM, "Gabe Black" <[email protected]> wrote: > >> My workstation doesn't have a version of gcc on it that hits the error, >> so it's going to be difficult for me to do very much debugging. The major >> difference I see between m5.opt and m5.fast, particularly on gcc of >> approximately the right versions, is that LTO is turned on. >> >> Gabe >> >> On Wed, May 24, 2017 at 7:04 PM, Gabe Black <[email protected]> wrote: >> >>> I think this has to do with the interaction between partial linking and >>> link time optimization. I'll keep looking into it. >>> >>> Gabe >>> >>> On Wed, May 24, 2017 at 2:00 PM, Jason Lowe-Power <[email protected]> >>> wrote: >>> >>>> Hi everyone, >>>> >>>> So I've been able to reproduce the problem. I would bet it's due to the >>>> new partial linking code (https://gem5.googlesource.com >>>> /public/gem5/+/6bdd897f04f4efdf90d0761c6d31d3f960f4eacf). I'm not sure >>>> what the solution is, yet, or if I'll have time to look at it in the next >>>> few day. Gabe might have an idea, though, if that is the problem. >>>> >>>> Here's a matrix of what compilers are working and which aren't (gcc-4.8 >>>> is working, too, though not tested on travis). >>>> https://travis-ci.org/powerjg/gem5-ci-test/builds/235779432 >>>> >>>> Jason >>>> >>>> On Tue, May 23, 2017 at 4:33 PM Moussa, Ayman < >>>> [email protected]> wrote: >>>> >>>>> How can I check which compiler scons uses? These are the compilers on >>>>> my system >>>>> >>>>> >>>>> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609 >>>>> g++ (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609 >>>>> Linux 4.4.0-75-generic #96-Ubuntu SMP >>>>> >>>>> ------------------------------ >>>>> *From:* gem5-users <[email protected]> on behalf of Jason >>>>> Lowe-Power <[email protected]> >>>>> *Sent:* 23 May 2017 22:27:34 >>>>> >>>>> *To:* gem5 users mailing list >>>>> *Subject:* Re: [gem5-users] Link error building gem5.fast >>>>> >>>>> I just tried again and still cannot reproduce the error. What compiler >>>>> are you using? >>>>> >>>>> Jason >>>>> >>>>> On Tue, May 23, 2017 at 3:41 PM Moussa, Ayman < >>>>> [email protected]> wrote: >>>>> >>>>>> Hey >>>>>> >>>>>> >>>>>> I've encountered this exact problem with x86 and it only seems to be >>>>>> for gem5.fast (gem5.opt works fine). I still have problems with a clean >>>>>> build as Jason suggested so I reverted back to some random commit on the >>>>>> gem5 repository and it works but it's not what I was looking for though. >>>>>> Hope this gets fixed soon. >>>>>> >>>>>> >>>>>> >>>>>> ------------------------------ >>>>>> *From:* gem5-users <[email protected]> on behalf of Alec >>>>>> Roelke <[email protected]> >>>>>> *Sent:* 23 May 2017 21:14:10 >>>>>> *To:* gem5 users mailing list >>>>>> *Subject:* [gem5-users] Link error building gem5.fast >>>>>> >>>>>> Hi Everyone, >>>>>> >>>>>> When I try to build gem5.fast using any ISA, I get a lot of multiple >>>>>> definition errors during the final linking stage. For example, with x86: >>>>>> >>>>>> [ LINK] -> X86/gem5.fast.unstripped >>>>>> build/X86/arch/x86/bios/lib.fo.partial: In function >>>>>> `Drainable::drainResume()': >>>>>> (.text+0x5b00): multiple definition of `Drainable::drainResume()' >>>>>> build/X86/dev/x86/lib.fo.partial:(.text+0x0): first defined here >>>>>> >>>>>> There are way too many of these to list them all, but they're all >>>>>> multiple definitions of symbols. Has anyone else encountered this? >>>>>> >>>>>> Thanks, >>>>>> Alec Roelke >>>>>> _______________________________________________ >>>>>> gem5-users mailing list >>>>>> [email protected] >>>>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>>> >>>>> _______________________________________________ >>>>> gem5-users mailing list >>>>> [email protected] >>>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>>> >>>> >>> >> >> _______________________________________________ >> gem5-users mailing list >> [email protected] >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >> > > _______________________________________________ > gem5-users mailing list > [email protected] > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >
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