Hi Gerrit,

Yes, that was the plan, but it looks like powerpc support was already added
to the sys/unix package last week.

When we were working on this package we first had several subtle and
difficult to debug problems.  As part of debugging, we developed unit tests
for validation of some of the system call bindings on powerpc using Qemu
and a physical device.

I still plan to check the differences between our version of these bindings
and the upstream version and check if this could result in problems (from
quickly looking at the commits I can say that our bindings should differ
from the upstream version, but I have no idea about the impact).

I will get back to this next week and post here what I find.

Hugo


On Thu, Oct 22, 2020 at 5:40 PM Gerrit Binnenmars <
gerritbinnenm...@gmail.com> wrote:

>
>
> Hello Hugo,
>
> I did not succeed in getting crosstool-ng produce a go tool. Instead I
> adapted the source of the "normal" go tool and simply removed the check and
> added a fmt.Fprintf instead. It shows that even with go build -compiler
> gccgo the test is first called with the gc compiler and then with the gccgo
> compiler. So the test will always fail. I assume I still am doing something
> wrong but don't understand what.
>
> Meanwhile with the adapted go tool I can build the mender client
> application with the ppc gccgo compiler. Next problem is the missing
> support for ppc in golang.org/x/sys/unix.
> I also noticed that the community is interested in this:
> https://github.com/golang/go/issues/37443
> Are you willing to share your unix package for ppc 32 bit architectures?
>
> With regards, Gerrit
> On Tuesday, October 20, 2020 at 9:52:17 AM UTC+2 hugo.c...@essensium.com
> wrote:
>
>>
>>
>> Hi Gerrit,
>>
>> If I understand correctly, I believe you try to cross-compile Go
>> applications to the PowerPC e500 architecture and as a first step you are
>> porting Go to this architecture.
>>
>> We recently ported Go applications such as Docker and its tools to
>> architectures not supported by upstream Go, but with an approach quite
>> different from yours (if I understood well).
>>
>> The procedure we follow, is:
>>
>> 1. Build the gccgo cross-toolchain with Buildroot: Buildroot currently
>> builds a toolchain by first building a gcc-initial, then proceeding to
>> build a gcc-final.  We had to insert a new gcc compilation stage before
>> gcc-final can build the gccgo cross-compiler.  This additional gcc
>> compilation stage makes go-tools available in the native environment that
>> are required for building the gccgo cross-compiler tools when gcc-final is
>> built.  If I understand well this may be an important part of the solution
>> to your problem.
>>
>> 2. Patch the Buildroot environment to invoke gccgo as the compiler,
>> rather than gc, for compiling Go applications.  We are planning to upstream
>> this and the previous step to Buildroot in the coming months.
>>
>> 3. Implement Go system call bindings: The sys package of the Go runtime
>> implements system call bindings as part of gccgo (so part of gcc-final),
>> the golang-sys/unix package is (can be) shipped in the folder
>> golang-sys/unix of the application you want to build (this is Docker and
>> tools in our case).  The golang-sys package needs to be patched in each
>> application to produce correct system call bindings for your target
>> environment (so the PowerPC e500 in your case).  Most of our development
>> time was spent in this last step (it is tricky).
>>
>> Using this procedure we have ported Docker and its dependencies and tools
>> to several ppc 32 bit architectures.
>>
>> I hope this helps.
>>
>> Hugo
>>
>>
>>
>> On Tue, Oct 20, 2020 at 6:20 AM gerritbinnenmars <gerritbi...@gmail.com>
>> wrote:
>>
>>> Hello Ian,
>>> Thanks for the quick reaction. It seems my request was not clear.
>>> What I am doing is the other way around: using gccgo to build the "go"
>>> cmd.
>>> So clone the "go" source from github and then go build -compiler gccgo
>>> ./cmd/go
>>>
>>> Gerrit
>>>
>>> -------- Oorspronkelijk bericht --------
>>> Van: Ian Lance Taylor <ia...@golang.org>
>>> Datum: 20-10-20 04:25 (GMT+01:00)
>>> Aan: Gerrit Binnenmars <gerritbi...@gmail.com>
>>> Cc: golang-nuts <golan...@googlegroups.com>
>>> Onderwerp: Re: [go-nuts] gccgo problem compiling go from source
>>>
>>> On Mon, Oct 19, 2020 at 2:06 PM Gerrit Binnenmars
>>> <gerritbi...@gmail.com> wrote:
>>> >
>>> > I used crosstool-ng successfully to build a go compiler for ppc e500.
>>> > Unfortunately go build does not support ppc therefore go needs to be
>>> > build from source using the amd64 gccgo compiler that I also build
>>> > with crosstool-ng.
>>> >
>>> > Compiling go from source fails:
>>> > Problem: undefined name stdpkg in internal/goroot/gccgo.go
>>> >
>>> > I included the output of my build script below. Any help or tips are
>>> welcome.
>>> >
>>> > With kind regards,
>>> >
>>> > Gerrit Binnenmars
>>> >
>>> > Info:
>>> > This is crosstool-NG version 1.24.0.191_364ed7a
>>> > GO111MODULE=""
>>> > GOARCH="amd64"
>>> > GOBIN=""
>>> > GOCACHE="/home/maintain/.cache/go-build"
>>> > GOENV="/home/maintain/.config/go/env"
>>> > GOEXE=""
>>> > GOFLAGS=""
>>> > GOHOSTARCH="amd64"
>>> > GOHOSTOS="linux"
>>> > GOINSECURE=""
>>> > GOMODCACHE="/home/maintain/gonew/pkg/mod"
>>> > GONOPROXY=""
>>> > GONOSUMDB=""
>>> > GOOS="linux"
>>> > GOPATH="/home/maintain/gonew"
>>> > GOPRIVATE=""
>>> > GOPROXY="https://proxy.golang.org,direct";
>>> >
>>> GOROOT="/home/maintain/x-tools/x86_64-e500-linux-gnu/x86_64-e500-linux-gnu/sysroot/lib"
>>> > GOSUMDB="sum.golang.org"
>>> > GOTMPDIR=""
>>> >
>>> GOTOOLDIR="/home/maintain/x-tools/x86_64-e500-linux-gnu/x86_64-e500-linux-gnu/sysroot/lib/pkg/tool/linux_amd64"
>>> > GCCGO="/home/maintain/x-tools/x86_64-e500-linux-gnu/bin/gccgo"
>>> > AR="ar"
>>> > CC="/home/maintain/x-tools/x86_64-e500-linux-gnu/bin/gcc"
>>> > CXX="/home/maintain/x-tools/x86_64-e500-linux-gnu/bin/g++"
>>> > CGO_ENABLED="1"
>>> > GOMOD=""
>>> >
>>> CGO_CFLAGS="--with-sysroot=/home/maintain/x-tools/x86_64-e500-linux-gnu/x86_64-e500-linux-gnu/sysroot"
>>> > CGO_CPPFLAGS=""
>>> > CGO_CXXFLAGS="-g -O2"
>>> > CGO_FFLAGS="-g -O2"
>>> > CGO_LDFLAGS="-g -O2"
>>> > PKG_CONFIG="pkg-config"
>>> > GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0
>>> > -fdebug-prefix-map=/tmp/go-build355977706=/tmp/go-build
>>> > -gno-record-gcc-switches"
>>> > go version go1.15.2 linux/amd64
>>> > gccgo (GCC) 10.2.0
>>> > Copyright (C) 2020 Free Software Foundation, Inc.
>>> > This is free software; see the source for copying conditions.  There
>>> is NO
>>> > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
>>> PURPOSE.
>>> >
>>> > WORK=/tmp/go-build273889551
>>> > mkdir -p $WORK/b100/
>>> > cd $WORK
>>> > /home/maintain/x-tools/x86_64-e500-linux-gnu/bin/gccgo
>>> > -fgo-importcfg=/dev/null -c -x c - -o /dev/null || true
>>> > cd /home/maintain/gonew/src/internal/goroot
>>> > /home/maintain/x-tools/x86_64-e500-linux-gnu/bin/gccgo -c -g -m64
>>> > -fdebug-prefix-map=$WORK=/tmp/go-build -gno-record-gcc-switches
>>> > -fgo-pkgpath=internal/goroot -o $WORK/b100/_go_.o -I
>>> > $WORK/b100/_importcfgroot_ ./gccgo.go
>>> > mkdir -p $WORK/b027/
>>> > mkdir -p $WORK/b027/_importcfgroot_/cmd/go/internal
>>> > ln -s
>>> /home/maintain/.cache/go-build/ad/ade44815e7af8b7305b2db4099ec5b08aafcbd6e374a2c13d8e99c2986ca93c6-d
>>> > $WORK/b027/_importcfgroot_/cmd/go/internal/libauth.a
>>> > ln -s
>>> /home/maintain/.cache/go-build/d2/d26f05f163d86aecfadfbb952dfef9a314aa1c84c23fddd39bce127ccc85d101-d
>>> > $WORK/b027/_importcfgroot_/cmd/go/internal/libcfg.a
>>> > mkdir -p $WORK/b027/_importcfgroot_/cmd/internal
>>> > ln -s
>>> /home/maintain/.cache/go-build/2f/2f6811b0804c481edbfd9952d1aac22414f84ee1aec229218b03956bf3f9aa7a-d
>>> > $WORK/b027/_importcfgroot_/cmd/internal/libbrowser.a
>>> > cd /home/maintain/gonew/src/cmd/go/internal/web
>>> > /home/maintain/x-tools/x86_64-e500-linux-gnu/bin/gccgo -c -g -m64
>>> > -fdebug-prefix-map=$WORK=/tmp/go-build -gno-record-gcc-switches
>>> > -fgo-pkgpath=cmd/go/internal/web -o $WORK/b027/_go_.o -I
>>> > $WORK/b027/_importcfgroot_ ./api.go ./http.go ./url.go ./url_other.go
>>> > # internal/goroot
>>> > src/internal/goroot/gccgo.go:24:10: error: reference to undefined name
>>> 'stdpkg'
>>> >    24 |   return stdpkg[path]
>>> >       |          ^
>>> > # cmd/go/internal/web
>>> > src/cmd/go/internal/web/api.go:92:45: error: reference to undefined
>>> > field or method 'Redacted'
>>> >    92 |   return nil, fmt.Errorf("reading %s: %v", u.Redacted(), err)
>>>
>>> It looks like you are using the "go" program to build the gccgo
>>> standard library.  That doesn't work.  The gccgo standard library must
>>> be built as part of GCC, using the usual configure/make commands used
>>> to build GCC itself.  When configuring GCC, use --enable-languages=go.
>>>
>>> Ian
>>>
>>> --
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>>>
>> --
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