From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39D0610F92FD for ; Tue, 31 Mar 2026 20:27:21 +0000 (UTC) Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) by mx.groups.io with SMTP id smtpd.msgproc01-g2.587.1774988835015191093 for ; Tue, 31 Mar 2026 13:27:16 -0700 Authentication-Results: mx.groups.io; dkim=pass header.i=@bootlin.com header.s=dkim header.b=vasfVmOV; spf=pass (domain: bootlin.com, ip: 185.246.85.4, mailfrom: thomas.perrot@bootlin.com) Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id C8FB04E42885; Tue, 31 Mar 2026 20:27:12 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 9AE046029D; Tue, 31 Mar 2026 20:27:12 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 1C6F4104502A1; Tue, 31 Mar 2026 22:27:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1774988831; h=from:subject:date:message-id:to:cc:mime-version:content-type: in-reply-to:references:autocrypt; bh=kd/BHLmlgSB7wlYUUNXEY76cNRO0Lejc57vOzYpYXOg=; b=vasfVmOVcxs74WpngMVaKUWMbhQDLflqcxf/QobZ0PQh9ZdAF11Po0m5w32Ecr8heZ9DiB RS0Lz6+UZ0cpS2UfVCCQ8g8IrA6L/G01n0M0AFfYFA5aK/nRE1jCr0ej+jcGexbGbYICzj gKmqXw+kwPXTMWchxLz//7UuDjm6oKGThinYYYSRFpdQOTH/0/uDnYkO8n7/246IfFhsSf 2+aCvjFWmG5ptaFcXDRkUso5kxsIi9ckMLdeRLAbFzDdn+ZbyPCYHj3SUEXt2/ZdyxyzS0 eUDgUq3pZNX+5iYcWTZ4Me9DAxls4qfo+znVwoVQXg3WXvm/+zHLphPbj78fKw== Message-ID: <9ea28268b4644e2c2db54a551c364298700ba619.camel@bootlin.com> Subject: Re: [OE-core][PATCH] lto: disable for expect and add DEBUG_PREFIX_MAP to ldflags From: Thomas Perrot To: raj.khem@gmail.com, joerg.sommer@navimatix.de Cc: thomas.perrot@bootlin.com, openembedded-core@lists.openembedded.org, thomas.petazzoni@bootlin.com Date: Tue, 31 Mar 2026 22:27:08 +0200 In-Reply-To: References: <20260331081246.73406-1-thomas.perrot@bootlin.com> Autocrypt: addr=thomas.perrot@bootlin.com; prefer-encrypt=mutual; keydata=mQGNBF+/ZOUBDAC2DghCjZvmgYcve02OG7dGZ7Iy58uEwne3LB7w7nRwdAxKw7ZaiVqwY O+yNGVi+GVx7oA6Wn4pv46z+QDRLQiq6OseuXhkSGCg7U/yBCUq12B/GRGO1Qt2Qi1mJJT1s+1qZ5 Gxv6Nypz9qKVn94GM2bR1hXBga0t87vBpebThOHmX5d/0dqIcVxRCM7onNb0dDyRoVgLS5rBhQzrL CMrJaCy39xZUy0J1SOlH4Mgk6EhJIPYY4wlzikGX6urg+Tc9EjGd78ry0e0p5U5qgjFR5QGJDy1Gn U3CfwbT9sowdCASDbQDUoltlv2iWJCLa0xl97KVchCa0pr7HKbFA3J5SLKqFYUBCkFL+5WudYlz2n XxiUgyviMQxyK+ij66kEi6/2zFDAecd43pHV7790ptqZBC3Jc67Emj7Vo3ShX6RXPPxxbeCTOF2uk I45aJ9XcVFH/MFE96NjXj8uahnIsiTPyuCUoJu8tj7TSQyue874qJqVQvqlFyt2aZYJZ8ruq8AEQE AAbQpVGhvbWFzIFBlcnJvdCA8dGhvbWFzLnBlcnJvdEBib290bGluLmNvbT6JAc4EEwEIADgCGwMF CwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQSHQHfGpqMKIwOoEiGfwAsFcf4K7QUCX79mdwAKCRCfw AsFcf4K7fhbC/wP0kSl6id2E/K3+UdXk6CLMVRbCFLCREzQs5WFpQ6l/I0WGOamhrOgegdszheiVF orlUP8d37XSpFAqydhKGaN78V5Dps0Wmwm4lIlS4MtQXJtSLUHXDJLIZLW0pw8tiPLKsd1o/yDkXE dnpsjJTRG6SdDSHnyOB2/gh4p+yTaLytFdARk/r4/P26+L+FiH0fFl+RnBt19LPklfKgeDc7GwIif ja+nIWpp3W23DAUuI6xduEut25Q89yu7Ci8CliLfAiLy9bIGjBQWU2Y+1/j/7KuPj6VbBsZWLTZY0 hUmpJSTnWAqc9SMsNxo7NSQuddgviz5e2tqucaRqxP02FGzNa8U4NAKdWaXrlHG5Dglj9XH0DK+SH +c96qqFewYD8VPQ6XAGxQcXbrtJmiMor1R2DfziispLRvJcfYs8xqabbCtoS3ouXB9XRi8hn7A2kh ME1ryS+Oh63JshXHnw6bmjCpVd/p+fGLIGU6A47pJOpviKR4jEO84pl2ejtDZ3Tc= Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-nmfEBCGQ0ZehydftkzsO" User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) MIME-Version: 1.0 X-Last-TLS-Session-Version: TLSv1.3 List-Id: X-Webhook-Received: from 45-33-107-173.ip.linodeusercontent.com [45.33.107.173] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Tue, 31 Mar 2026 20:27:21 -0000 X-Groupsio-URL: https://lists.openembedded.org/g/openembedded-core/message/234314 --=-nmfEBCGQ0ZehydftkzsO Content-Type: multipart/alternative; boundary="=-Z6txMMEAWyLUZydpP4B0" --=-Z6txMMEAWyLUZydpP4B0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hello, On Tue, 2026-03-31 at 12:45 -0700, Khem Raj via lists.openembedded.org wrote: >=20 >=20 > On Tue, Mar 31, 2026 at 8:40=E2=80=AFAM J=C3=B6rg Sommer via > lists.openembedded.org > wrote: > > Thomas Perrot via lists.openembedded.org schrieb am Di 31. M=C3=A4r, > > 10:12 (+0200): > > > From: Thomas Perrot > > >=20 > > > Disable LTO for the expect package and append DEBUG_PREFIX_MAP to > > > TARGET_LDFLAGS when LTO is enabled, ensuring debug info remapping > > > is applied consistently alongside LTO flags. > > >=20 > > > Signed-off-by: Thomas Perrot > > > --- > > >=C2=A0 meta/conf/distro/include/lto.inc | 1 + > > >=C2=A0 1 file changed, 1 insertion(+) > > >=20 > > > diff --git a/meta/conf/distro/include/lto.inc > > b/meta/conf/distro/include/lto.inc > > > index 8752249685a4..c66dfc5a8074 100644 > > > --- a/meta/conf/distro/include/lto.inc > > > +++ b/meta/conf/distro/include/lto.inc > > > @@ -4,6 +4,7 @@ > > >=C2=A0 # > > >=C2=A0=20 > > >=C2=A0 # Disable LTO for following packages > > > +LTO:pn-expect =3D "" > >=20 > > I suspect this is due to the gcc bug not because LTO is unsuitable > > for > > expect. Might it be a good idea to move all excludes due to the gcc > > bug in > > its own block? This would make it easier to revert them when the > > bug gets > > resolved. > >=20 > >=20 >=20 >=20 > I also wonder if the issue is gcc specific and works with TOOLCHAIN =3D > "clang" I investigated further and can confirm your suspicion, this is indeed a GCC bug, not an incompatibility between LTO and expect. = = = = =20 With -v added to LDFLAGS, I verified that -ffile-prefix-map flags=20 are correctly passed to lto1. However, the raw TMPDIR path does not come from expect's own compilation, it leaks from tcl8 via the=20 .debug_line_str section: $ readelf --debug-dump=3Dline libexpect5.45.4.so | grep '/src/build'=20 0 (indirect line string, offset: 0x7de):=20 /src/build/tmp/work/.../tcl8/8.6.17/build=20 = = = = =20 During LTO, when GCC incorporates debug info from a linked dependency (tcl8 here), the directory entries in .debug_line_str are not subject=20 to prefix remapping. DW_AT_comp_dir is correctly remapped, but=20 .debug_line_str is not.=20 = = = = =20 This is not expect-specific, any package linking against tcl8 with LTO=20 could be affected. = = = = =20 Your suggestion to group packages disabled due to this GCC bug=20 in a separate block, I think it's a good idea. Kind regards, Thomas > =C2=A0 > > >=C2=A0 LTO:pn-glibc =3D "" > > >=C2=A0 LTO:pn-gcc-runtime =3D "" > > >=C2=A0 LTO:pn-libgcc-initial =3D "" > > > --=20 > > > 2.53.0 > > >=20 > >=20 > > >=20 > > >=20 > > >=20 > >=20 > >=20 > > -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- > > Links: You receive all messages sent to this group. > > View/Reply Online (#234313): > > https://lists.openembedded.org/g/openembedded-core/message/234313 > > Mute This Topic: > > https://lists.openembedded.org/mt/118593189/5443093 > > Group Owner: openembedded-core+owner@lists.openembedded.org > > Unsubscribe: > > https://lists.openembedded.org/g/openembedded-core/unsub=C2=A0[ > > thomas.perrot@bootlin.com] > > -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- > >=20 --=20 Thomas Perrot, Bootlin Embedded Linux and kernel engineering https://bootlin.com --=-Z6txMMEAWyLUZydpP4B0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Hello,

On Tu= e, 2026-03-31 at 12:45 -0700, Khem Raj via lists.openembedded.org wrote:

<= br>
On Tue, Mar 31, 2026 at 8:40=E2=80=AFAM J=C3=B6rg Sommer vi= a lists.openembedded.org <= joerg.sommer=3Dnavim= atix.de@lists.openembedded.org> wrote:
Thomas Perrot via lists.openembedded.org schrieb am Di = 31. M=C3=A4r, 10:12 (+0200):
> From: Thomas Perrot <thomas.perrot@bootlin.com<= /a>>
>
> Disable LTO for the expect package and append DEBU= G_PREFIX_MAP to
> TARGET_LDFLAGS when LTO is enabled, ensuring debug = info remapping
> is applied consistently alongside LTO flags.
>=
> Signed-off-by: Thomas Perrot <thomas.perrot@bootlin.com>
> --= -
>  meta/conf/distro/include/lto.inc | 1 +
>  1 file= changed, 1 insertion(+)
>
> diff --git a/meta/conf/distro/inc= lude/lto.inc b/meta/conf/distro/include/lto.inc
> index 8752249685a4.= .c66dfc5a8074 100644
> --- a/meta/conf/distro/include/lto.inc
>= +++ b/meta/conf/distro/include/lto.inc
> @@ -4,6 +4,7 @@
>&nbs= p; #
> 
>  # Disable LTO for following packages
&= gt; +LTO:pn-expect =3D ""

I suspect this is due to the gc= c bug not because LTO is unsuitable for
expect. Might it be a good idea = to move all excludes due to the gcc bug in
its own block? This would mak= e it easier to revert them when the bug gets
resolved.


I also wonder if the issue is g= cc specific and works with TOOLCHAIN =3D "clang"

I investigated further and ca= n confirm your suspicion, this is indeed a GCC bug,
not an incomp= atibility between LTO and expect.

= = = = =
With -v added to LDFLAGS, I verified that -ffile-prefix-map = flags = = =
are correctly passed to lto1. H= owever, the raw TMPDIR path does not
come from expect's own com= pilation, it leaks from tcl8 via the = = =
= .debug_line_str section:

$ readelf --debug-d= ump=3Dline libexpect5.45.4.so | grep '/src/build' = = =
0 (indirect line string, offset: 0x7de):
= /src/build/tmp/work/.../tcl8/8.6.17/build = = = =
= = = =
During LTO, when GCC i= ncorporates debug info from a linked dependency
(tcl8 here), th= e directory entries in .debug_line_str are not subject = = = =
to prefix remapping. DW_AT_comp_dir is correctly remapped, bu= t = = =
.debug_line_str is not. = = = =
= = = = =
This is not expect-specific, any package linking = against tcl8 with LTO = = =
could be affected.

= = = =
Your suggestion to gr= oup packages disabled due to this GCC bug = = =
in= a separate block, I think it's a good idea.

Kin= d regards,
Thomas

 
>  LTO:pn-glib= c =3D ""
>  LTO:pn-gcc-runtime =3D ""
>  LTO:pn-libgc= c-initial =3D ""
> --
> 2.53.0
>

>=
>
>


-=3D-=3D-= =3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-
Links: You receive all m= essages sent to this group.

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