Date: Wed, 18 May 2022 13:28:25 -0700 From: John Baldwin <jhb@FreeBSD.org> To: Brooks Davis <brooks@freebsd.org>, Dimitry Andric <dim@FreeBSD.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Charlie Li <vishwin@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@freebsd.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@freebsd.org> Subject: Re: git: 349cc55c9796 - main - Merge llvm-project main llvmorg-14-init-10186-gff7f2cfa959b Message-ID: <82300056-132d-38c3-4a1b-521004c776f9@FreeBSD.org> In-Reply-To: <20220518193537.GH15201@spindle.one-eyed-alien.net> References: <202205141148.24EBmkZd015765@gitrepo.freebsd.org> <e251f1fb-b0c2-1d3a-d9f2-6def1ddb9735@freebsd.org> <C45D4583-C972-426A-88F0-42F475D760D2@FreeBSD.org> <4b61bdc6-fdc7-57df-e9b7-52543fd083be@freebsd.org> <20220516154825.GF15201@spindle.one-eyed-alien.net> <e57160f3-5d34-69cb-c249-f4f0f0665282@freebsd.org> <5e5281b2-a9d1-3751-b09a-c88d210f4f55@FreeBSD.org> <YoQ%2B8LupA6XG6F/a@kib.kiev.ua> <698AE22D-5E95-405E-A8BE-AE67A3A7BE36@FreeBSD.org> <20220518193537.GH15201@spindle.one-eyed-alien.net>
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On 5/18/22 12:35 PM, Brooks Davis wrote: > On Wed, May 18, 2022 at 09:17:58PM +0200, Dimitry Andric wrote: >> On 18 May 2022, at 02:33, Konstantin Belousov <kostikbel@gmail.com> wrote: >>> >>> On Tue, May 17, 2022 at 10:56:14AM -0700, John Baldwin wrote: >>>> On 5/16/22 8:09 PM, Charlie Li wrote: >>>>> Brooks Davis wrote: >>>>>> On Mon, May 16, 2022 at 10:47:49AM -0400, Charlie Li wrote: >>>>>>> Dimitry Andric wrote: >>>>>>>> This was also reported by another user, and it turned out they were >>>>>>>> using WITHOUT_CROSS_COMPILER= in src.conf. If you also have that, try >>>>>>>> removing it and rebuilding. >>>>>>>> >>>>>>> Yeah I eventually figured that part out. Worked around (first attempt) >>>>>>> by building with devel/llvm14 CROSS_TOOLCHAIN, but resulted in certain >>>>>>> kernel modules (zfs and a few more) with malformed relocations. >>>>>>> Subsequent rebuild with the new world's toolchain corrected that. >>>>>> >>>>>> Does that mean we're missing patches in the port? Hopefully anything >>>>>> this critical can be merged into LLVM 14.0.3. >>>>>> >>>>> Probably: >>>>> >>>>> May 15 22:34:08 current-builder kernel: ---<<BOOT>>--- >>>>> May 15 22:34:08 current-builder kernel: Copyright (c) 1992-2022 The >>>>> FreeBSD Project. >>>>> May 15 22:34:08 current-builder kernel: Copyright (c) 1979, 1980, 1983, >>>>> 1986, 1988, 1989, 1991, 1992, 1993, 1994 >>>>> May 15 22:34:08 current-builder kernel: The Regents of the >>>>> University of California. All rights reserved. >>>>> May 15 22:34:08 current-builder kernel: FreeBSD is a registered >>>>> trademark of The FreeBSD Foundation. >>>>> May 15 22:34:08 current-builder kernel: FreeBSD 14.0-CURRENT #121 >>>>> main-n255657-48a1a6be196: Sun May 15 21:59:12 EDT 2022 >>>>> May 15 22:34:08 current-builder kernel: >>>>> root@current-builder:/usr/obj/usr/src/amd64.amd64/sys/GENERIC-NODEBUG amd64 >>>>> May 15 22:34:08 current-builder kernel: clang version 14.0.2 >>>>> [...] >>>>> May 15 22:34:08 current-builder kernel: kldload: unexpected relocation >>>>> type 42, symbol index 8321 >>>> >>>> These are all type 42: >>>> >>>> #define R_X86_64_REX_GOTPCRELX 42 >>>> >>>> It's not a LLVM bug so much as it is probably missing support in the kernel and/or >>>> loader for this type of relocation. kldxref might also need updating. >>>> >>>> I suspect due to a mismatch of old lld with new clang or some such that the old >>>> lld failed to resolve these relocations to some other type or something weird like >>>> that? >>> >>> I do think this is a toolchain bug, or at least new and undesired behavior. >>> >>> For practical purposes, R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX are >>> same as R_X86_64_GOTPCREL64, I believe, but we do not expect GOT relocations >>> in the .o object modules on amd64. >> >> I don't see this with clang 14.0.3 from base on 14-CURRENT. None of my >> kernel modules has any of these relocations, and I also get no warnings >> from kldxref. >> >> Btw, I know that clang from ports will use /usr/local/bin/ld if it is >> available, so this might be GNU ld specific behavior? Charlie, do you >> have the binutils port installed? > > I don't believe this is true in all but the weirdest configurations. I > just tested on a system with binutils installed (providing > /usr/local/bin/ld) and clang13 uses /usr/local/llvm13/bin/ld as I'd > expect. Because of the foo## wrappers, clang doesn't know it's being > found via /usr/local/bin so doesn't look there by default. Instead it's > invoked as /usr/local/llvm##/bin/clang and looks for > /usr/local/llvm##/bin/ld. Maybe if you didn't install LLD it would > eventually look in PATH and find /usr/local/bin/ld. It gets more odd if you install amd64-binutils (used by amd64-gcc[69]) as that installs a x86-64-unknown-freebsd13.0-ld binary that clang will find and use. However, Charlie reported he only got this during the transition where the tree in /usr/obj had LLVM 14 but /usr had LLVM 13, so I'm not sure what the cause is or if it is even reproducible. -- John Baldwin
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