how to debug go build errors

[Martin Sebor]

On 02/08/2018 05:39 PM, Ian Lance Taylor wrote:
> On Thu, Feb 8, 2018 at 3:24 PM, Martin Sebor <msebor@gmail.com> wrote:
>>
>> While testing what should be an innocuous patch to add LTO
>> to a bunch of middle-end warning options
>>
>>   https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00381.html
>>
>> I get Go errors during ordinary bootstrap about undefined names
>> for errno constants:
>>
>> /opt/notnfs/msebor/src/gcc/84212/libgo/go/syscall/env_unix.go:96:10: error:
>> reference to undefined name ‘EINVAL’
>>
>> Bootstrapping all other front ends (including Ada and Brig),
>> succeeds and there are no regressions in the test suite.
>>
>> I have no experience with Go.  Does anything about the patch
>> jump out at you that could be causing this?  If not, can you
>> suggest how to debug it?
>
> No, I don't see why your patch would cause this problem.
>
> EINVAL should be defined in the generated file
> TARGET/libgo/sysinfo.go.  You should see, among many others, the lines
>     const _EINVAL = 22
> and
>     const EINVAL = Errno(_EINVAL)
>
> That file is built by the shell script libgo/mksysinfo.sh, which looks
> at the generated file TARGET/libgo/gen-sysinfo.go.  The gen-sysinfo.go
> file is built by running the C compiler with the -fdump-go-spec option
> on the file libgo/sysinfo.c (essentially GCC_FOR_TARGET
> -fdump-go-spec=gen-sysinfo.go -std=gnu99 -S sysinfo.c).  I guess
> something along that chain has broken, but I don't know what.

I've figured out what was causing it -- a silly typo.  (Our
emails must have crossed by barely a couple of minutes).
Thanks for the quick reply though!

Martin