[pkg-golang-devel] Bug#891746: golang-defaults: Please disable golang-go, golang-src and golang for ppc64

[John Paul Adrian Glaubitz]

Source: golang-defaults
Version: 2:1.10~1
Severity: normal
User: debian-powerpc at lists.debian.org
Usertags: ppc64

Hi!

With golang-1.9, Golang upstream unfortunately decided to drop POWER4
support from the Go compiler so that golang-1.9 and newer require
a POWER8 machine to build golang on ppc64 [1].

While the change upstream doesn't really make much sense as there is
no port of Linux that I know of that uses the POWER8 baseline for a
ppc64 big-endian port (everyone uses the little-endian port) meaning
the effective number of users of golang on ppc64 big-endian drops to
zero, I was unable to convince upstream to revert this change. Most
likely because I joined the discussion too late and the decision was
already made.

Although I have to say the assumptions made upstream are not correct
as the PowerMac G5 is definitely not the only 64-bit PowerPC machine
on the market which has a lower baseline than POWER8. There are designs
based on embedded CPUs by Freescale, for example, like the PowerPC
e5500 and e6500. But since the ppc64 port of Golang is maintained by
IBM, I don't think there is much we can do to change their minds.

We do have one buildd in Debian Ports, kapitsa, which is a POWER8
machine capable of building golang-1.9. However, since the official
baseline of the port is POWER4 without Altivec, any Go binaries
built with golang-1.9 or newer on the buildd kapitsa would not be
usable for most of our users.

We can still keep building golang-1.9 and golang-1.10 on ppc64,
I will actually change the buildd configuration to limit these
two packages to the buildd kapitsa. However, the default implementation
of golang on ppc64 should be gccgo from now on and we will trigger
a binNMU of all Go packages after this particular change has been
made.

Hence, please stop building golang-go, golang-src and golang for
ppc64.

Thanks,
Adrian

> [1] https://github.com/golang/go/issues/19074

--
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz at debian.org
`. `'   Freie Universitaet Berlin - glaubitz at physik.fu-berlin.de
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