Re: Linking Abseil in Compiler Explorer?

[Matt Godbolt]

Hi CJ! (and CCing the development mailing list)

Got it! For the longest time CE only supported header-only libraries. Somewhat recently we added support for linking, and @Patrick Quist is our expert on that side of things.

Partouf; do you have any thoughts on how best to move forward? I know https://godbolt.org/admin/libraries.html has abseil in it already -- that means it's already being built I think by our systems, so it's _feasible_ it might "just work" - the `conan` server backing this serves recipes that may have the link (or lack therin) already covered...I am embarrassed to say this is a large area of the CE code I don't know well!

We really appreciate you considering the implications of changing the library on CE users: thanks!

--matt

On Tue, Mar 16, 2021 at 6:10 PM CJ Johnson <john...@google.com> wrote:

Hello Matt!

I'm a member of the Core Libraries team at Google. We're working on a change to our constexpr inline variables such that they are defined in a CC.

There seems to be an issue with Compiler Explorer where Abseil CCs are not linked in. We've known about this for a while, but it has not been a big concern since so much of Abseil is header-only. Since the library will soon change to use CCs in more cases, we expect this to break many existing Compiler Explorer links that use Abseil.

What needs to be done such that Abseil can be properly linked in Compiler Explorer?

Thanks! - CJ

--

Matt

(he/him)

[CJ Johnson]

Thank you for the prompt response!

You mentioned Conan. Is that the package manager you use? Looking at their Abseil listing, it seems they only provide LTS branches. That means the change may not reach Compiler Explorer for a while. That said, I think it's a good idea to get ahead of this issue. - CJ

[CJ Johnson]

(Re-sending without internal only list)

Thank you for the prompt response!

You mentioned Conan. Is that the package manager you use? Looking at their Abseil listing, it seems they only provide LTS branches. That means the change may not reach Compiler Explorer for a while. That said, I think it's a good idea to get ahead of this issue. - CJ

On Tue, Mar 16, 2021 at 7:21 PM Matt Godbolt <ma...@godbolt.org> wrote:

[Matt Godbolt]

We do our own Conan packaging, mainly using conan as a binary repository, if I understand correctly. We don't use the public Conan packages, we build from trunk nightly.

[CJ Johnson]

Brilliant! That's great to hear.

[CJ Johnson]

Hey Matt!

Is there a status update on this?

Thanks, - CJ

[Matt Godbolt]

Hi CJ,

Sorry I've let the ball drop completely on this. Let me work out what's needed and get back to you.

--matt

--

Matt

(he/him)

[Matt Godbolt]

Oh!

The amazing Patrick had already fixed this: https://github.com/compiler-explorer/compiler-explorer/issues/2512 - it has been fixed for a few weeks noe but we forgot to get back to you!

Hopefully that's the good news you were after! :)

Thanks, Matt

--

Matt

(he/him)

[CJ Johnson]

Thank you for addressing this! - CJ