libgo patch committed: Change build procedure to use build tags

On Thu, Aug 11, 2016 at 8:15 AM, Rainer Orth
<ro@cebitec.uni-bielefeld.de> wrote:
>
>> Go packages use build tags (see the section on Build Constraints at
>> https://golang.org/pkg/go/build/) to select which files to build on
>> specific systems.
>>
>> Previously the libgo Makefile explicitly listed the set of files to
>> compile for each package.  For packages that use build tags, this
>> required a lot of awkward automake conditionals in the Makefile.
>>
>> This patch changes the build to look at the build tags in the files.
>> The new shell script libgo/match.sh does the matching.  This required
>> adjusting a lot of build tags, and removing some files that are never
>> used.  I verified that the exact same sets of files are compiled on
>> x86_64-pc-linux-gnu.  I also tested the build on i386-sun-solaris
>> (building for both 32-bit and 64-bit).
>>
>> Writing match.sh revealed some bugs in the build tag handling that
>> already exists, in a slightly different form, in the gotest shell
>> script.  This patch fixes those problems as well.
>>
>> The old code used automake conditionals to handle systems that were
>> missing strerror_r and wait4.  Rather than deal with those in Go,
>> those functions are now implemented in runtime/go-nosys.c when
>> necessary, so the Go code can simply assume that they exist.
>>
>> The os testsuite looked for dir_unix.go, which was never built for
>> gccgo and has now been removed.  I changed the testsuite to look for
>> dir.go instead.
>>
>> Note that if you have an existing build directory, you will have to
>> remove all the .dep files in TARGET/libgo after updating to this
>> patch.  There isn't anything that will force them to update
>> automatically.
>>
>> Bootstrapped on x86_64-pc-linux-gnu and i386-sun-solaris.  Ran Go
>> testsuite on x86_64-pc-linux-gnu.  Committed to mainline.
>
> this patch broke i386-pc-solaris2.12 and sparc-sun-solaris2.12
> bootstrap, however: in both cases, the 64-bit build of os.lo fails like this:
>
> /vol/gcc/src/hg/trunk/local/libgo/go/os/dir.go:82:8: error: reference to undefined name 'libc_readdir_r'
>    i := libc_readdir_r(file.dirinfo.dir, entryDirent, pr)
>         ^
>
> Neither dir_largefile.go (which is correctly omitted, being 32-bit only)
> nor dir_regfile.go (which is needed here) is included in the
> compilation.

Sorry, I don't know what I messed up in my testing.  I committed the
appended patch, which should fix the problem.

Ian

Hi Ian,

>> this patch broke i386-pc-solaris2.12 and sparc-sun-solaris2.12
>> bootstrap, however: in both cases, the 64-bit build of os.lo fails like this:
>>
>> /vol/gcc/src/hg/trunk/local/libgo/go/os/dir.go:82:8: error: reference to undefined name 'libc_readdir_r'
>>    i := libc_readdir_r(file.dirinfo.dir, entryDirent, pr)
>>         ^
>>
>> Neither dir_largefile.go (which is correctly omitted, being 32-bit only)
>> nor dir_regfile.go (which is needed here) is included in the
>> compilation.
>
> Sorry, I don't know what I messed up in my testing.  I committed the
> appended patch, which should fix the problem.

I had found a different one to the same effect, but running match.sh
with yours looked right, too.

There's now one new failure, 32 and 64-bit, sparc and x86:

+FAIL: syscall

libgo.log shows

libcalls.go:825:1: error: redefinition of 'Getpgid'
 func Getpgid(pid int) (pgid int, err error) {
 ^
exec_solaris_test.go:22:1: note: previous definition of 'Getpgid' was here
 func Getpgid(pid int) (pgid int, err error) {
 ^
libcalls.go:843:1: error: redefinition of 'Getpgrp'
 func Getpgrp() (pid int) {
 ^
exec_solaris_test.go:31:1: note: previous definition of 'Getpgrp' was here
 func Getpgrp() (pgrp int) {
 ^
exec_solaris_test.go:14:3: error: libc_Getpgid is not a function; //go:linkname is only supported for functions
 //go:linkname libc_Getpgid libc_Getpgid
   ^
exec_solaris_test.go:15:3: error: libc_Getpgrp is not a function; //go:linkname is only supported for functions
 //go:linkname libc_Getpgrp libc_Getpgrp
   ^
exec_solaris_test.go:23:15: error: reference to undefined name 'sysvicall6'
  r0, _, e1 := sysvicall6(uintptr(unsafe.Pointer(&libc_Getpgid)), 1, uintptr(pid), 0, 0, 0, 0, 0)
               ^
exec_solaris_test.go:32:14: error: reference to undefined name 'sysvicall6'
  r0, _, _ := sysvicall6(uintptr(unsafe.Pointer(&libc_Getpgrp)), 0, 0, 0, 0, 0, 0, 0)
              ^
exec_solaris_test.go:37:13: error: reference to undefined name 'ioctl'
 var Ioctl = ioctl
             ^
exec_solaris_test.go:19:15: error: use of undefined type 'libcFunc'
  libc_Getpgrp libcFunc
               ^

I've no idea what exec_solaris_test.go is about: e.g.I couldn't find any
other reference to sysvicall6 elsewhere in the gcc tree.

	Rainer

Hi Ian,

>>> this patch broke i386-pc-solaris2.12 and sparc-sun-solaris2.12
>>> bootstrap, however: in both cases, the 64-bit build of os.lo fails like this:
>>>
>>> /vol/gcc/src/hg/trunk/local/libgo/go/os/dir.go:82:8: error: reference to undefined name 'libc_readdir_r'
>>>    i := libc_readdir_r(file.dirinfo.dir, entryDirent, pr)
>>>         ^
>>>
>>> Neither dir_largefile.go (which is correctly omitted, being 32-bit only)
>>> nor dir_regfile.go (which is needed here) is included in the
>>> compilation.
>>
>> Sorry, I don't know what I messed up in my testing.  I committed the
>> appended patch, which should fix the problem.
>
> I had found a different one to the same effect, but running match.sh
> with yours looked right, too.

here's another issue found during wider testing: on Solaris 10 with
/bin/ksh as CONFIG_SHELL, the build aborts like this:

objcopy: 'bufio.o': No such file
Makefile:5072: recipe for target 'bufio.gox' failed
make[4]: *** [bufio.gox] Error 1

It turns out that no bufio.o is created indeed:

/vol/gcc/src/hg/trunk/local/libgo/../install-sh -c -d .; files=`echo  | sed -e 's/[^ ]*\.gox//g' -e 's/[^ ]*\.dep//'`; /bin/ksh ./libtool --tag GO --mode=compile /var/gcc/regression/trunk/10-gcc/build/./gcc/gccgo -B/var/gcc/regression/trunk/10-gcc/build/./gcc/ -B/vol/gcc/i386-pc-solaris2.10/bin/ -B/vol/gcc/i386-pc-solaris2.10/lib/ -isystem /vol/gcc/i386-pc-solaris2.10/include -isystem /vol/gcc/i386-pc-solaris2.10/sys-include     -minline-all-stringops  -g -O2 -I . -c -fgo-pkgpath=`echo bufio.lo | sed -e 's/.lo$//' -e 's/-go$//'` -o bufio.lo $files

The list of input files, output from the likes of

/bin/ksh /vol/gcc/src/hg/trunk/local/libgo/match.sh --goarch=386 --goos=solaris --srcdir=/vol/gcc/src/hg/trunk/local/libgo/go/bufio --extrafiles=""

is empty.  Running match.sh with /bin/ksh -x reveals

+ set -e
+ unset LANG

where the script aborts.  It turns out that /bin/ksh errors out on an
unset of a variable that isn't set.

Maybe one could explicitly set LANG=C here, or use the `portable unset'
used in configure?

Thanks.
        Rainer