[go-nuts] go 1.4beta1 + SWIG 3.0.3-dev can't build

On Wednesday, November 5, 2014 2:20:52 AM UTC+1, Steeve Morin wrote:

Hi,

I'm trying to build my package https://github.com/steeve/libtorrent-go
using SWIG.
I've built SWIG from source from today's master, and it runs okay.

However, when I try to build the generated package inside my go program, I
get this:

C source files not allowed when not using cgo: libtorrent_gc.c

Looking at the code in golang, I decide to add import "C" to
libtorrent_gc.c (why SWIG doesn't do it itself is an open question,
should it?).

Running the build again, it starts to build okay, but fails at:

../libtorrent-go/libtorrent_gc.c:34:10: fatal error: 'runtime.h' file not
found

If I remove the file, it builds okay, but the program fails to start
because the symbols are not set (this is what this file does)
Here is a quick preview of the file, just in case:
http://pastebin.com/dPVZZL5T

Here is the full output with -x -v: http://pastebin.com/AL2fKWij
Here is the full output when creating libtorrent-go:
http://pastebin.com/EzebdV4t

Also, as I understand it, 5c/6c/8c will be removed at some point. What is
the suggested way of moving forward for these cases?

Thank you!

On Wednesday, November 5, 2014 2:41:00 AM UTC+1, Steeve Morin wrote:

I've done some more test, and found that if I try to go build the package,
somehow it's gcc who is executed against the libtorrent_gc.c file, not 6c:

WORK=/tmp/go-build185137340
github.com/steeve/libtorrent-go
mkdir -p $WORK/github.com/steeve/libtorrent-go/_obj/
mkdir -p $WORK/github.com/steeve/
cd /Users/steeve/projects/go/src/github.com/steeve/libtorrent-go
CGO_LDFLAGS="-g" "-O2" /usr/local/go/pkg/tool/linux_amd64/cgo -objdir
$WORK/github.com/steeve/libtorrent-go/_obj/ -- -I $WORK/
github.com/steeve/libtorrent-go/_obj/ libtorrent.go
/usr/local/go/pkg/tool/linux_amd64/6c -F -V -w -trimpath $WORK -I $WORK/
github.com/steeve/libtorrent-go/_obj/ -I /usr/local/go/pkg/linux_amd64 -o
$WORK/github.com/steeve/libtorrent-go/_obj/_cgo_defun.6 -D GOOS_linux -D
GOARCH_amd64 $WORK/github.com/steeve/libtorrent-go/_obj/_cgo_defun.c
gcc -I . -fPIC -m64 -pthread -fmessage-length=0 -print-libgcc-file-name
gcc -I . -fPIC -m64 -pthread -fmessage-length=0 -I $WORK/
github.com/steeve/libtorrent-go/_obj/ -g -O2 -o $WORK/
github.com/steeve/libtorrent-go/_obj/_cgo_main.o -c $WORK/
github.com/steeve/libtorrent-go/_obj/_cgo_main.c
gcc -I . -fPIC -m64 -pthread -fmessage-length=0 -I $WORK/
github.com/steeve/libtorrent-go/_obj/ -g -O2 -o $WORK/
github.com/steeve/libtorrent-go/_obj/_cgo_export.o -c $WORK/
github.com/steeve/libtorrent-go/_obj/_cgo_export.c
gcc -I . -fPIC -m64 -pthread -fmessage-length=0 -I $WORK/
github.com/steeve/libtorrent-go/_obj/ -g -O2 -o $WORK/
github.com/steeve/libtorrent-go/_obj/libtorrent.cgo2.o -c $WORK/
github.com/steeve/libtorrent-go/_obj/libtorrent.cgo2.c
gcc -I . -fPIC -m64 -pthread -fmessage-length=0 -I $WORK/
github.com/steeve/libtorrent-go/_obj/ -g -O2 -o $WORK/
github.com/steeve/libtorrent-go/_obj/libtorrent_gc.o -c ./libtorrent_gc.c
# github.com/steeve/libtorrent-go
./libtorrent_gc.c:34:21: fatal error: runtime.h: No such file or directory
compilation terminated.

On Tue, Nov 4, 2014 at 7:15 PM, Steeve Morin wrote:

Ok so I've gone further by having go itself invoke SWIG, via a
swigcxx file (which was not easy since I had a lot of -D on the
command line, it would be nice if Go could propagate them the way it
does for -I).

Using a .swigcxx file is the right approach.


I'm troubled by the leading underscores here. The later message shows
an ELF file, but ELF doesn't use leading underscores. Darwin does use
leading underscores, but then why would you have an ELF file?

A couple of things I didn't see mentioned: what platform are you on,
and what version of Go are you using?

This is a problem that you need to fix.

Unfortunately it's a completely useless error message, as it doesn't
provide enough information to know the architecture. It's a 64-bit
little-endian ELF file, but it doesn't say the processor.

Perhaps your default compiler does not generate x86_64 ELF files. Is
that possible?

Ian

On Tue, Nov 4, 2014 at 7:43 PM, Steeve Morin wrote:
I am cross compiling to darwin from a Linux host indeed, so what I get from you is that somewhere $CC or $CXX isn't called? But rather plain old gcc (from the host, that is)?

On Wednesday, November 5, 2014 5:01:27 AM UTC+1, Ian Lance Taylor wrote:

On Tue, Nov 4, 2014 at 7:43 PM, Steeve Morin <[email protected]
<javascript:>> wrote:
from you is that somewhere $CC or $CXX isn't called? But rather plain old
gcc (from the host, that is)?

It should indeed call $CC or $CXX in all cases. If you have set those
environment variables to the cross-compiler you need, then something
else is happening.

Can you show us the go build -x output when using the .swigcxx file?

Ian


wrote:
<javascript:>> wrote:
built
0x00
being
built
0x00
being

On Wednesday, November 5, 2014 1:58:24 PM UTC+1, Steeve Morin wrote:

Hey Ian,

Thanks for looking into this.

Here is the full output:
https://gist.github.com/steeve/8f9adf78c282bb8ffc2f
Just in case, please note that I've cut the warning (there's lot of them).

Also, the weird thing is that if I only have one .go file (libtorrent.go)
that does the import "C", it doesn't compile saying there's no go file, so
I need that empty.go one.

Steeve

On Wednesday, November 5, 2014 4:13:18 PM UTC+1, Steeve Morin wrote:

I have also ran file on all the .o files generated

https://gist.github.com/steeve/8f9adf78c282bb8ffc2f#file-files

They are all Mach-O, as expected.