Re: [PATCH] gold: Use autotools pthread macro

[Joshua Watt <jpewhacker at gmail dot com>]

On Sat, Feb 17, 2018 at 4:42 PM, Cary Coutant <ccoutant@gmail.com> wrote:
>> The autotools library macro (AX_PTHREAD) is now used to detect if
>> pthreads is present and multi-threaded linking in gold is automatically
>> enabled if it is found. This enables multi-threaded gold on platforms
>> where pthreads is enabled via other methods than just -lpthread (e.g.
>> MinGW)
>>
>> Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
>> ---
>>  config/ax_pthread.m4       | 485 ++++++++++++++++++++++++++++
>>  gold/Makefile.am           |  11 +-
>>  gold/Makefile.in           |  22 +-
>>  gold/aclocal.m4            |   1 +
>>  gold/configure             | 767 +++++++++++++++++++++++++++++++++++++++++++--
>>  gold/configure.ac          |  23 +-
>>  gold/testsuite/Makefile.in |   8 +-
>>  7 files changed, 1254 insertions(+), 63 deletions(-)
>
> Thanks for the patch! I have a few preliminary questions and comments...
>
> First, do you or your company have a copyright assignment on file with FSF?

I do not. What is the process for that? I don't need a company
assignment, an individual contributor for me will be fine.

If I sign that for this project, would it also cover GCC, or do I need
one for each?

>
> I could be wrong, but I believe adding to config/ will require
> approval from a GCC config/ maintainer. The normal process, as I
> understand it, would be to add the file to the GCC tree, then sync it
> into the binutils tree. I'm not in a position to approve that, nor can
> I judge on the acceptability of the copyright notice in that file.

Ok. I didn't realize the config/ directory came from GCC. I'll look
into getting it submitted there.... How does that get "synced" to
binutils? Would I make a patch to add it here after it is added there?

FWIW, it is the same license as the ax_check_define macro (also from
the autotools macro archive) that is already in config/

>
> I'd like to retain the ability to use --disable-threads as a configure option.
>

I will add that back in.

> If this is just to get MinGW on board, is there a lighter-weight way
> of doing that? Could we just add a configure option that switches
> between -lpthread and -pthread (or whatever option is needed)? I like
> the idea of fully automating it, but that's a pretty big m4 file!

It is pretty large.... I pulled it straight from the autoconf macro
archive. IMHO, its much better quality than anything I would be able
to come up with otherwise, and pretty brain-dead easy for the end
user. It should "just work" without any special switches (although the
user *can* configure it with some env-vars I think).

>
> Anyway, I'd like to hear what the GCC folks think of adding
> ax_pthread.m4 to the config/ directory.
>
> (BTW, In the future, please omit diffs from generated files from your patch.)

Will do. I couldn't find a lot of examples of config changes in
binutils, but I thought the one that I did updated the generated files
also. I must have been mistaken.

>
> -cary

Thanks,
Joshua Watt