From nobody Tue Aug 10 20:56:56 2021 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 784E4137B3DD; Tue, 10 Aug 2021 20:56:58 +0000 (UTC) (envelope-from brooks@spindle.one-eyed-alien.net) Received: from spindle.one-eyed-alien.net (spindle.one-eyed-alien.net [199.48.129.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Gklcn2K2Xz5414; Tue, 10 Aug 2021 20:56:57 +0000 (UTC) (envelope-from brooks@spindle.one-eyed-alien.net) Received: by spindle.one-eyed-alien.net (Postfix, from userid 3001) id 7BAF03C0199; Tue, 10 Aug 2021 20:56:56 +0000 (UTC) Date: Tue, 10 Aug 2021 20:56:56 +0000 From: Brooks Davis To: Ed Maste Cc: "freebsd-toolchain@FreeBSD.org" , FreeBSD Hackers Subject: Re: Compressed debug info sections and big-endian targets Message-ID: <20210810205656.GD4352@spindle.one-eyed-alien.net> References: List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@freebsd.org MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+g7M9IMkV8truYOl" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Rspamd-Queue-Id: 4Gklcn2K2Xz5414 X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=none (mx1.freebsd.org: domain of brooks@spindle.one-eyed-alien.net has no SPF policy when checking 199.48.129.229) smtp.mailfrom=brooks@spindle.one-eyed-alien.net X-Spamd-Result: default: False [-2.78 / 15.00]; TO_DN_EQ_ADDR_SOME(0.00)[]; TO_DN_SOME(0.00)[]; SIGNED_PGP(-2.00)[]; FORGED_SENDER(0.30)[brooks@freebsd.org,brooks@spindle.one-eyed-alien.net]; RCVD_COUNT_ZERO(0.00)[0]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; ASN(0.00)[asn:36236, ipnet:199.48.128.0/22, country:US]; FROM_NEQ_ENVFROM(0.00)[brooks@freebsd.org,brooks@spindle.one-eyed-alien.net]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FREEFALL_USER(0.00)[brooks]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; DMARC_NA(0.00)[freebsd.org]; AUTH_NA(1.00)[]; NEURAL_SPAM_SHORT(0.12)[0.117]; R_SPF_NA(0.00)[no SPF record] X-ThisMailContainsUnwantedMimeParts: N --+g7M9IMkV8truYOl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Aug 07, 2021 at 12:07:39PM -0400, Ed Maste wrote: > GCC and Clang/LLVM support coimpressed debug info, which compresses > the .debug_* ELF sections in objects, archives, libraries, and > executables. I recently committed build infrastructure changes to turn > this on (c910570e7573) but it broke the build on big-endian targets > (mips, powerpc) and so disabled it again (89ed2ecb14ce). PR257638 has > more details. >=20 > The lld bug is now fixed in main thanks to Simon Atanasyan upstream > and dim@ for merging it over (d69d07569ee2), and I would like to > enable it again. I've committed the fix to devel/llvm12 and will merge to quarterly. I'll follow up with an update to llvm-devel. I've not investigated if it can be merged to older ports. > An outstanding issue is that the bug is triggered by the linker's > input, and so this will occur if we attempt to link against a base > system .a archive using a buggy lld. In the short term I think we have > no choice but to leave compressed debug disabled on BE targets, until > fixed lld versions are available in ports/packages. >=20 > I have a review open to enable it for LE targets only: > https://reviews.freebsd.org/D31454. >=20 > I'd like to apply that change for now, but would like to enable > compressed debug across all targets in the future. This would break, > on big-endian targets, any port that has a build-dependency on an > older lld and links against a base system archive. Such a port could > be fixed by switching to linking with binutils ld, or lld from the > base system or a newer package. What do big-endian mips or powerpc > users think? I'd be surprised if it was significant for mips given the generally sorry state of the port. Might be more exciting for powerpc where X11 works. (As an aside, I suspect we'll have updated CHERI-LLVM to ~13 before we've caught CheriBSD up to this change and we may even manage to give mips the boot before then.) -- Brooks --+g7M9IMkV8truYOl Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJhEugXAAoJEKzQXbSebgfAEJMH/RhfpD7pn/OXZBby78CtPcDu 1og1+UJsnhrjiu6gIFRiCQ6WR0f6n/I+PKkbyOCYPLLXX8oaKotOIvwDRQrIoy3b KThFRJOFsHOV4V+QX3BhqohW5VvvLiMtyzpTokrFaD1zagZGfwDmULMRWIJwkiK3 Ady/uy8+HVLBctIoADkipsxMreX7CYndOU/u0a20g5JP6WUk9l/vXwI3nq6PSYmT iY8urxXb+muRa/hvrm49h+5U/TUq+9RVzpS8Ike3nPOd0uy3/bMdMw+AAyfWbedM U7texYoxU99G+1muIv6grHy+8lA+1qYSFYiYhW4ldMBll3RAix0detrzierJPVA= =/dJt -----END PGP SIGNATURE----- --+g7M9IMkV8truYOl--