Re: Hi Matt

[Matt Godbolt]

Hi Raphael, (CCing our development taem)

Compiler Explorer is open source! You can make the changes you need! The details are mostly in https://github.com/compiler-explorer/compiler-explorer/blob/master/docs/AddingALibrary.md -- you will need to make two PRs:

* One to our infra repository: *adding* a new line with the version to https://github.com/compiler-explorer/infra/blob/61aa64271e46990e4666baa1f94dddbbf4e50518/bin/yaml/libraries.yaml#L260-L265

* One to our compiler explorer repository: *adding* an extra line to https://github.com/compiler-explorer/compiler-explorer/blob/67c72338d4e51427981f919b545d03065bab9659/etc/config/c%2B%2B.amazon.properties#L1304-L1309 to handle the new version

I don't know what you mean about the model of compiling against the application: we don't install or build most of the libraries we use (there's a separate conan process ongoing). I'm not sure how that would affect our ability to generate code? Hopefully takinga  look at how Compiler Explorer works, and knowing your own system you'll be able to help.

Please note that we don't ever remove old versions: we keep everything around so people can compare before/after of different compilers and library versions.

Thanks, Matt :)

On Mon, Sep 14, 2020 at 9:08 AM Raphael S. Carvalho <raph...@scylladb.com> wrote:

On Wed, Sep 9, 2020 at 7:32 PM Matt Godbolt <ma...@godbolt.org> wrote:
>
> Hi Raphael,
>
> Nice to hear from you! Seastar's been on Compiler Explorer a while now (we added it last year). I don't know much about seastar, but in general to use a library on Compiler Explorer, one selects it from the "Libraries" dropdown on the compiler, then #includes it as one would normally.
>
> I just tried using the example from the "Seastar Tutorial" and it seems seastar needs boost. So I picked a version of boost too, and then a version of fmt (the latest version didn't work, MemoryWrite is not a member fmt), so I picked a 4.0.0 version. This is very old, but newer versions didn't seem to work either.
>
> Compilation was unfortunately so slow that it nearly timed out - taking 30ish seconds... https://godbolt.org/z/qnTdTx was the result if it gives some ideas!
>
> Obviously we can update the version of seastar on the site if 18.08 is old. I don't know how you'd want to use it though; at this compile time it's unfortunately not very interactive, which is mostly what Compiler Explorer is used for.  I imagine our file IO is not fast enough: most of the libraries are stored on NFS (boost is a special case) and we've had issues with that before.
>
> Let me know if that answers your question, and if I can help more!

Hi Matt,

Thanks for the quick reply!

BTW, newer Seastar versions have better compilation time and have a
much faster approach to compile applications, see:
https://github.com/scylladb/seastar/tree/5a68003f0385d9dc3d25d50ffb7a9a50cf7c2206#using-an-installed-seastar

On previous versions, you were probably stuck with the model where
parts of Seastar library were compiled along with the application. Is
godbolt using this approach to compile seastar-based apps:
https://github.com/scylladb/seastar/tree/5a68003f0385d9dc3d25d50ffb7a9a50cf7c2206#using-seastar-from-its-build-directory-without-installation
?

We, Seastar developers, would appreciate a lot if you could please
update Godbolt to use seastar-20.05.0 instead, and switch to the
compilation mode described in the section 'Using an installed Seastar'
of the README doc.


Regards,
Raphael Carvalho



>
> Thanks, Matt
>
>
> On Wed, Sep 9, 2020 at 3:37 PM Raphael S. Carvalho <raph...@scylladb.com> wrote:
>>
>> Hi,
>>
>> My name is Raphael. I work on ScyllaDb and Seastar, and I saw godbolt
>> has recently added support to the seastar library. Could you please
>> share instructions on how to use it on godbolt? Is there any doc
>> available?
>>
>> Regards,
>> Raphael Carvalho
>
>
>
> --
> Matt

--

Matt