RFC: remove the "tile" architecture from glibc

[John Paul Adrian Glaubitz]

On 12/04/2017 12:10 PM, Adhemerval Zanella wrote:
>> I will be happy to provide these test runs. I just came from OpenJDK were
>> I fixed many issues with non-stream architectures and I'm happy to pick
>> up glibc next and try to help fix issues.
> 
> There is some time I checked glibc status on m68k (and looks like I can't
> access the machine now) and I can try to see if I can make/check glibc on
> the machine (I am trying to recall why exactly prevented me to so on 2.26
> release window).

This particular machine (an Aranym instance) is down at the moment. I do
have an Amiga 4000 here now up and running and I also did a testsuite
run on qemu-m68k-system which eventually bails out with:

gcc /srv/glibc/build/math/test-tgmath3.c -c -std=gnu11 -fgnu89-inline  -O2 -Wall -Werror -Wundef -Wwrite-strings -fmerge-all-constants -fno-stack-protector -frounding-math -g -Wstrict-prototypes -Wold-style-definition   -fno-builtin       -D__NO_MATH_INLINES -D__LIBC_INTERNAL_MATH_INLINES -I../include -I/srv/glibc/build/math  -I/srv/glibc/build  -I../sysdeps/unix/sysv/linux/m68k/m680x0  -I../sysdeps/unix/sysv/linux/m68k  -I../sysdeps/m68k/nptl  -I../sysdeps/unix/sysv/linux/include -I../sysdeps/unix/sysv/linux  -I../sysdeps/nptl  -I../sysdeps/pthread  -I../sysdeps/gnu  -I../sysdeps/unix/inet  -I../sysdeps/unix/sysv  -I../sysdeps/unix  -I../sysdeps/posix  -I../sysdeps/m68k/m680x0/m68020  -I../sysdeps/m68k/m680x0/fpu  -I../sysdeps/m68k/m680x0  -I../sysdeps/ieee754/ldbl-96/include -I../sysdeps/ieee754/ldbl-96  -I../sysdeps/m68k/fpu  -I../sysdeps/m68k  -I../sysdeps/wordsize-32  -I../sysdeps/ieee754/dbl-64  -I../sysdeps/ieee754/flt-32  -I../sysdeps/ieee754  -I../sysdeps/generic  -I.. -I../libio -I.   -D_LIBC_REENTRANT -include /srv/glibc/build/libc-modules.h -DMODULE_NAME=testsuite -include ../include/libc-symbols.h       -DTOP_NAMESPACE=glibc -o /srv/glibc/build/math/test-tgmath3.o -MD -MP -MF /srv/glibc/build/math/test-tgmath3.o.dt -MT /srv/glibc/build/math/test-tgmath3.o
virtual memory exhausted: Cannot allocate memory
../o-iterator.mk:9: recipe for target '/srv/glibc/build/math/test-tgmath3.o' failed
make[2]: *** [/srv/glibc/build/math/test-tgmath3.o] Error 1
make[2]: Leaving directory '/srv/glibc/math'
Makefile:215: recipe for target 'math/xtests' failed
make[1]: *** [math/xtests] Error 2
make[1]: Leaving directory '/srv/glibc'
Makefile:9: recipe for target 'xcheck' failed
make: *** [xcheck] Error 2

The source code file in question is 11 MiB large:

root@pacman:/srv/glibc/build# ls -lh /srv/glibc/build/math/test-tgmath3.c
-rw-r--r-- 1 root root 11M Dec  2 19:37 /srv/glibc/build/math/test-tgmath3.c
root@pacman:/srv/glibc/build#

>> I have already contacted the guy who has started with ia64 again on
>> Debian and warned him about the deprecation issue.
> 
> I would be nice if we could get access to real ia64 hardware (I tried to
> use ski with mixed results).  ia64 thread stack allocation was broken
> since 2.24 (d615a4735) and we just fixed it recently on master (01b87c656f)
> and only though reports of Sergei Trofimovich (my ski environment did not
> trigger the issue).

The guy working on ia64 in Debian is Jason Duerstock. He said, he will be
willing to provide a porterbox for ia64 soonish. I put him up in the CC
of this mail.

>> SH has LRA support in gcc already, if I remember correctly.
> 
> I see Linux/m68k being deprecated if and when we move to a minimum required
> GCC version which does not support m68k (I do not think we have a policy
> to remove deprecated architecture in GCC latest version where there is still
> compiler support in older releases).

I want to try my best to avoid this. There are many people currently hacking
on Linux/m68k and there has been a tremendous effort in the past 5-6 years
to resurrect the port. We are currently successfully building 10500 source
packages on Linux/m68k out of approximately 12000 packages which I don't
think is a too bad coverage.

> Now back to thread topic, Chris Metcalf gave us some indications that
> tilepro userbase and support do not justify the maintaining effort.  It
> already has kernel ABI incompatibilities (for instance ca768667d873 fix on
> linux and some atomic unsupported operations that broke the build on
> recent glibc fixes).  I think we could at least remove old tilepro
> support.

FWIW, Debian is focusing on tilegx which is currently bootstrappable
with gcc-7, see: https://jenkins.debian.net/view/rebootstrap/job/rebootstrap_tilegx_gcc7_supported/

Adrian

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