GNU bug report logs - #44531
27.1; Emacs 27 fails to build from source on m68k (regression)

Previous Next

To reply to this bug, email your comments to 44531 AT debbugs.gnu.org.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: bug-gnu-emacs <at> gnu.org
Subject: 27.1; Emacs 27 fails to build from source on m68k (regression)
Date: Mon, 09 Nov 2020 14:30:34 +0100

Hello!

Starting with version 27, Emacs has started failing to build from source
on m68k (Linux) with the following error message:

/bin/mkdir -p ../etc
/usr/bin/make -C ../lisp update-subdirs
make[4]: Entering directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
make[4]: Leaving directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
cp -f temacs bootstrap-emacs
rm -f bootstrap-emacs.pdmp
./temacs --batch  -l loadup --temacs=pbootstrap
Loading loadup.el (source)...
dump mode: pbootstrap
Using load-path (/<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/progmodes /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/language /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/international /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/textmodes /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc)
Loading emacs-lisp/byte-run (source)...
Loading emacs-lisp/backquote (source)...
Loading subr (source)...
Loading version (source)...
(...)
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/vc-hooks.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/ediff-hook.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/uniquify.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/electric.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp/eldoc.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/cus-start.el (source)...
Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/tooltip.el (source)...
Finding pointers to doc strings...
Finding pointers to doc strings...done
Dumping under the name bootstrap-emacs.pdmp
dumping fingerprint: 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
dump relocation out of range

Full build log available in [1].

I have not been able to figure out what "dump relocation out of range"
actually means, so any explanation is much appreciated.

Thanks,
Adrian

> [1] https://buildd.debian.org/status/fetch.php?pkg=emacs&arch=m68k&ver=1%3A27.1%2B1-3&stamp=1604857999&raw=0

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz <at> debian.org
`. `'   Freie Universitaet Berlin - glaubitz <at> physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #10 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: Acknowledgement (27.1; Emacs 27 fails to build from
 source on m68k (regression))
Date: Mon, 9 Nov 2020 20:34:18 +0100

Hi!

The problem can be worked around by configuring emacs with "--with-dumping=unexec",
so it seems the new portable dumper is incompatible with m68k.

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz <at> debian.org
`. `'   Freie Universitaet Berlin - glaubitz <at> physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #13 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>,
 Daniel Colascione <dancol <at> dancol.org>
Cc: 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1;
 Emacs 27 fails to build from source on m68k (regression)
Date: Sat, 21 Nov 2020 09:47:54 +0200

> From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
> Date: Mon, 09 Nov 2020 14:30:34 +0100
> 
> Hello!
> 
> Starting with version 27, Emacs has started failing to build from source
> on m68k (Linux) with the following error message:
> 
> /bin/mkdir -p ../etc
> /usr/bin/make -C ../lisp update-subdirs
> make[4]: Entering directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
> make[4]: Leaving directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
> cp -f temacs bootstrap-emacs
> rm -f bootstrap-emacs.pdmp
> ./temacs --batch  -l loadup --temacs=pbootstrap
> Loading loadup.el (source)...
> dump mode: pbootstrap
> Using load-path (/<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/progmodes /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/language /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/international /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/textmodes /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc)
> Loading emacs-lisp/byte-run (source)...
> Loading emacs-lisp/backquote (source)...
> Loading subr (source)...
> Loading version (source)...
> (...)
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/vc-hooks.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/ediff-hook.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/uniquify.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/electric.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp/eldoc.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/cus-start.el (source)...
> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/tooltip.el (source)...
> Finding pointers to doc strings...
> Finding pointers to doc strings...done
> Dumping under the name bootstrap-emacs.pdmp
> dumping fingerprint: 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
> dump relocation out of range
> 
> Full build log available in [1].
> 
> I have not been able to figure out what "dump relocation out of range"
> actually means, so any explanation is much appreciated.

Daniel, any advice for how to go about this problem?

Message #16 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Daniel Colascione <dancol <at> dancol.org>
To: Eli Zaretskii <eliz <at> gnu.org>,
 John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1;
 Emacs 27 fails to build from source on m68k (regression)
Date: Sat, 21 Nov 2020 00:07:28 -0800

On November 20, 2020 11:48:09 PM Eli Zaretskii <eliz <at> gnu.org> wrote:

>> From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
>> Date: Mon, 09 Nov 2020 14:30:34 +0100
>>
>> Hello!
>>
>> Starting with version 27, Emacs has started failing to build from source
>> on m68k (Linux) with the following error message:


m68k is big endian, isn't it? Try building with enable-checking to see 
whether we can see where the bit rearrangement problem might be.

>>
>> /bin/mkdir -p ../etc
>> /usr/bin/make -C ../lisp update-subdirs
>> make[4]: Entering directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
>> make[4]: Leaving directory '/<<BUILDDIR>>/emacs-27.1+1/debian/build-gtk/lisp'
>> cp -f temacs bootstrap-emacs
>> rm -f bootstrap-emacs.pdmp
>> ./temacs --batch  -l loadup --temacs=pbootstrap
>> Loading loadup.el (source)...
>> dump mode: pbootstrap
>> Using load-path (/<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/progmodes 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/language 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/international 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/textmodes 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc)
>> Loading emacs-lisp/byte-run (source)...
>> Loading emacs-lisp/backquote (source)...
>> Loading subr (source)...
>> Loading version (source)...
>> (...)
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/vc-hooks.el 
>> (source)...
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/vc/ediff-hook.el 
>> (source)...
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/uniquify.el 
>> (source)...
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/electric.el 
>> (source)...
>> Loading 
>> /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/emacs-lisp/eldoc.el 
>> (source)...
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/cus-start.el 
>> (source)...
>> Loading /<<BUILDDIR>>/emacs-27.1+1/debian/build-src/lisp/tooltip.el (source)...
>> Finding pointers to doc strings...
>> Finding pointers to doc strings...done
>> Dumping under the name bootstrap-emacs.pdmp
>> dumping fingerprint: 
>> 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
>> dump relocation out of range
>>
>> Full build log available in [1].
>>
>> I have not been able to figure out what "dump relocation out of range"
>> actually means, so any explanation is much appreciated.
>
> Daniel, any advice for how to go about this problem?

Message #19 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: Daniel Colascione <dancol <at> dancol.org>, Eli Zaretskii <eliz <at> gnu.org>
Cc: 44531 <at> debbugs.gnu.org, Andreas Schwab <schwab <at> linux-m68k.org>
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Mon, 23 Nov 2020 13:35:22 +0100

(CC'ing Andreas)

On 11/21/20 9:07 AM, Daniel Colascione wrote:
>>> Starting with version 27, Emacs has started failing to build from source
>>> on m68k (Linux) with the following error message:
> 
> 
> m68k is big endian, isn't it? Try building with enable-checking to see whether we can see where the bit rearrangement problem might be.

Thanks, I'll give it a try. My suspicion would be that it's an alignment problem
since the native alignment for m68k on Linux/sysv is 16 bits, not 32 bits.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz <at> debian.org
`. `'   Freie Universitaet Berlin - glaubitz <at> physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #22 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Daniel Colascione <dancol <at> dancol.org>,
 Andreas Schwab <schwab <at> linux-m68k.org>, 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Wed, 08 Sep 2021 11:48:15 +0200

John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de> writes:

>> m68k is big endian, isn't it? Try building with enable-checking to
>> see whether we can see where the bit rearrangement problem might be.
>
> Thanks, I'll give it a try. My suspicion would be that it's an
> alignment problem since the native alignment for m68k on Linux/sysv is
> 16 bits, not 32 bits.

This was almost a year ago -- did you get any further in debugging this
problem?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #27 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Daniel Colascione <dancol <at> dancol.org>,
 Andreas Schwab <schwab <at> linux-m68k.org>, 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Wed, 8 Sep 2021 13:28:04 +0200

Hi Lars!

On 9/8/21 11:48, Lars Ingebrigtsen wrote:
> John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de> writes:
> 
>>> m68k is big endian, isn't it? Try building with enable-checking to
>>> see whether we can see where the bit rearrangement problem might be.
>>
>> Thanks, I'll give it a try. My suspicion would be that it's an
>> alignment problem since the native alignment for m68k on Linux/sysv is
>> 16 bits, not 32 bits.
> 
> This was almost a year ago -- did you get any further in debugging this
> problem?

I think the problem was the new dumper that is used by default on emacs27 [1].

I know that I built emacs27 successfully on m68k with the option changed back,
let me try that again.

Adrian

> [1] https://lists.debian.org/debian-68k/2020/11/msg00009.html

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz <at> debian.org
`. `'   Freie Universitaet Berlin - glaubitz <at> physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #30 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Daniel Colascione <dancol <at> dancol.org>,
 Andreas Schwab <schwab <at> linux-m68k.org>, 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Thu, 07 Oct 2021 11:19:24 +0200

Lars Ingebrigtsen <larsi <at> gnus.org> writes:

> This was almost a year ago -- did you get any further in debugging this
> problem?

More information was requested, but no response was given within a
month, so it seems unlikely that there'll be further progress here, and
I'm closing this bug report.  If progress can be made, please respond to
this email and we'll reopen the bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #33 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Daniel Colascione <dancol <at> dancol.org>,
 Andreas Schwab <schwab <at> linux-m68k.org>, 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Thu, 07 Oct 2021 11:20:40 +0200

Lars Ingebrigtsen <larsi <at> gnus.org> writes:

> More information was requested, but no response was given within a
> month, so it seems unlikely that there'll be further progress here, and
> I'm closing this bug report.  If progress can be made, please respond to
> this email and we'll reopen the bug report.

Please disregard -- I hit the wrong button when responding here.  The
bug report has not been closed.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

Message #36 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: Lars Ingebrigtsen <larsi <at> gnus.org>
Cc: Eli Zaretskii <eliz <at> gnu.org>, Daniel Colascione <dancol <at> dancol.org>,
 Andreas Schwab <schwab <at> linux-m68k.org>, 44531 <at> debbugs.gnu.org
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Thu, 7 Oct 2021 11:37:06 +0200

Hi Lars!

On 10/7/21 11:19, Lars Ingebrigtsen wrote:
> Lars Ingebrigtsen <larsi <at> gnus.org> writes:
> 
>> This was almost a year ago -- did you get any further in debugging this
>> problem?
> 
> More information was requested, but no response was given within a
> month, so it seems unlikely that there'll be further progress here, and
> I'm closing this bug report.  If progress can be made, please respond to
> this email and we'll reopen the bug report.

As I said, building with the old dumper fixes the problem. Using the new
pdumper causes the crash. The issue still hasn't been fixed.

I'm not an emacs expert, so I don't know how to fix this bug.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz <at> debian.org
`. `'   Freie Universitaet Berlin - glaubitz <at> physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #41 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: 44531 <at> debbugs.gnu.org, Daniel Colascione <dancol <at> dancol.org>
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Sat, 02 Jul 2022 15:28:33 -0400

> dumping fingerprint: 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
> dump relocation out of range

This error message basically says that the relation is not a multiple of
the minimum expected alignment.  So it seems to be a direct consequence
of the 16bit alignment used on m68k combined with the following from
pdumper.el:

   [...]
   DUMP_RELOC_ALIGNMENT_BITS = 2,

   /* Minimum alignment required by dump file format.  */
   DUMP_RELOCATION_ALIGNMENT = 1 << DUMP_RELOC_ALIGNMENT_BITS,
   [...]

I can't see anything in the code which explains what this alignment
requirement is about.  You can try lowering DUMP_RELOC_ALIGNMENT_BITS
to 1 and see if that works (long shot).
Daniel?


        Stefan

Message #44 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Pip Cet <pipcet <at> gmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 44531 <at> debbugs.gnu.org, Daniel Colascione <dancol <at> dancol.org>,
 John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Subject: Re: bug#44531: 27.1;
 Emacs 27 fails to build from source on m68k (regression)
Date: Sat, 23 Jul 2022 14:42:58 +0000

On Sat, Jul 2, 2022 at 7:29 PM Stefan Monnier via Bug reports for GNU
Emacs, the Swiss army knife of text editors <bug-gnu-emacs <at> gnu.org>
wrote:
> > dumping fingerprint: 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
> > dump relocation out of range
>
> This error message basically says that the relation is not a multiple of
> the minimum expected alignment.  So it seems to be a direct consequence
> of the 16bit alignment used on m68k combined with the following from
> pdumper.el:

pdumper.c, I think :-)

>    [...]
>    DUMP_RELOC_ALIGNMENT_BITS = 2,
>
>    /* Minimum alignment required by dump file format.  */
>    DUMP_RELOCATION_ALIGNMENT = 1 << DUMP_RELOC_ALIGNMENT_BITS,
>    [...]
>
> I can't see anything in the code which explains what this alignment
> requirement is about.  You can try lowering DUMP_RELOC_ALIGNMENT_BITS
> to 1 and see if that works (long shot).

IIUC, the top (DUMP_RELOC_TYPE_BITS - DUMP_RELOC_ALIGNMENT_BITS) of
the relocation offsets stored by pdumper must be 0. That means we can
only address the first 512 MB of the dump in ordinary 32-bit pdumper
builds, and 256 MB on m68k with your fix. I'm not sure how useful a
data point this is without real silicon, but I tried on an m68k
emulator (qemu), could reproduce the bug, and your fix works there.

Pip

Message #47 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Pip Cet <pipcet <at> gmail.com>
Cc: 44531 <at> debbugs.gnu.org, Daniel Colascione <dancol <at> dancol.org>,
 John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Tue, 16 Aug 2022 17:38:25 -0400

>>    [...]
>>    DUMP_RELOC_ALIGNMENT_BITS = 2,
>>
>>    /* Minimum alignment required by dump file format.  */
>>    DUMP_RELOCATION_ALIGNMENT = 1 << DUMP_RELOC_ALIGNMENT_BITS,
>>    [...]
>>
>> I can't see anything in the code which explains what this alignment
>> requirement is about.  You can try lowering DUMP_RELOC_ALIGNMENT_BITS
>> to 1 and see if that works (long shot).
>
> IIUC, the top (DUMP_RELOC_TYPE_BITS - DUMP_RELOC_ALIGNMENT_BITS) of
> the relocation offsets stored by pdumper must be 0. That means we can
> only address the first 512 MB of the dump in ordinary 32-bit pdumper
> builds, and 256 MB on m68k with your fix. I'm not sure how useful a
> data point this is without real silicon, but I tried on an m68k
> emulator (qemu), could reproduce the bug, and your fix works there.

Any hope you can turn that into a patch?
Maybe with something like `#ifdef (__m68k__)`?


        Stefan

Message #50 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 44531 <at> debbugs.gnu.org, Daniel Colascione <dancol <at> dancol.org>
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Sun, 4 Sep 2022 10:02:06 +0200

Hello!

On 7/2/22 21:28, Stefan Monnier wrote:
>> dumping fingerprint: 7b5c59c589dc151eb1e4269bd83fbe809616b5cb9bb5c80014d5b560b391dfb6
>> dump relocation out of range
> 
> This error message basically says that the relation is not a multiple of
> the minimum expected alignment.  So it seems to be a direct consequence
> of the 16bit alignment used on m68k combined with the following from
> pdumper.el:
> 
>     [...]
>     DUMP_RELOC_ALIGNMENT_BITS = 2,
> 
>     /* Minimum alignment required by dump file format.  */
>     DUMP_RELOCATION_ALIGNMENT = 1 << DUMP_RELOC_ALIGNMENT_BITS,
>     [...]
> 
> I can't see anything in the code which explains what this alignment
> requirement is about.  You can try lowering DUMP_RELOC_ALIGNMENT_BITS
> to 1 and see if that works (long shot).
> Daniel?

I just gave lowering DUMP_RELOC_ALIGNMENT_BITS to 1 and it fixes the problem
for me. Maybe DUMP_RELOC_ALIGNMENT_BITS could be set depending on the native
alignment of the host machine?

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Message #53 received at 44531 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: John Paul Adrian Glaubitz <glaubitz <at> physik.fu-berlin.de>
Cc: 44531 <at> debbugs.gnu.org, Daniel Colascione <dancol <at> dancol.org>
Subject: Re: bug#44531: 27.1; Emacs 27 fails to build from source on m68k
 (regression)
Date: Sun, 04 Sep 2022 12:05:48 -0400

> I just gave lowering DUMP_RELOC_ALIGNMENT_BITS to 1 and it fixes the problem
> for me. Maybe DUMP_RELOC_ALIGNMENT_BITS could be set depending on the native
> alignment of the host machine?

That's right.
If someone can come up with a corresponding patch that would be great.
The alignment is a question of ABI convention, so I'm not sure how best
to do it, but maybe something like:

    struct dummy
    {
      char a;
      Lisp_Object b;
    }

    #define DUMP_RELOC_ALIGNMENT_BITS log2 (offsetof (struct dummy, b))

?


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.