Enforce minimum supported versions of GCC and Clang #10969

phire · 2022-08-10T03:09:58Z

With the move to C++20, and various people wanting to clean up the codebase to use the fancy new features, many PRs have run into problems older versions of clang running on buildbots.

It would be very helpful to actually define and enforce a minimum version of Clang/GCC so that it's clear what C++20 features contributors are allowed to use. Additionally... enforcing it in cmake gives users clear feedback about what's wrong before they even start, instead of random compile errors.

We already have an explicit minimum required version of Visual Studio, so it's not too outrageous. And various implicit minimum requirements on other versions.

Why not feature detection?

That doesn't really answer the question of "what C++20 features are we allowed to use", contributors would have to remember to add feature detection when using new C++20 features, and we would end up implicitly dropping support for versions of compilers without realising it.

What versions?

I've chosen Clang 11 as a minimum because that's the version in the latest stable release of FreeBSD. And we have a FreeBSD builder (which currently all the way back on Clang 6, released March 2018, so no wonder it's been unhappy about new C++20 syntax). It's also the minimum for (partial) support of consteval.

And GCC 10 seems to be roughly equivalent. Also the minimum for consteval. Both were released in 2020.

phire · 2022-08-10T03:35:46Z

@endrift are you happy updating the freebsd builder to FreeBSD 13.0 or 13.1?

Or should we do something different?

endrift · 2022-08-10T03:36:26Z

Yeah, lemme do that in a bit. Might be a little tricky but I'll try.

Contributing.md

phire · 2022-08-10T05:20:46Z

For the GCC version, there is an argument to be made that since we don't have a GCC 10.x builder, that we should skip over it and just require the GCC 11.x that our ubuntu uses.

I'm not sure how much extra distro compatibility GCC 10.x gains us.

Ubuntu's releases skips straight from gcc 9 to gcc 11
Debian's latest stable release is on gcc 10 (our Debian builders use clang)
Fedora is uses gcc 11 on their oldest still supported release.

phire · 2022-08-10T07:49:51Z

FreeBSD apparently updated to Clang 13 with the 13.1 release and didn't mention it in their release notes. But I think we should stick with clang 11 and GCC 10 as our minimums for now (especially with stable Debian still on GCC 10)

The FreeBSD buildbot has been updated to 13.1

OatmealDome · 2022-08-10T07:59:33Z

The latest steamrt used for games (version 1, 'scout') only has gcc-9, which is annoying. It might be possible to just install a newer gcc if we set up a steamrt build worker in the future.

This isn't something we have to worry about right now, anyway.

phire · 2022-08-10T08:09:25Z

Compiler shouldn't be a huge issue. It's a runtime, not a build-time. We don't want to be restrained to the compiler version it uses anyway.

However.... that might put some strain on our minimum libstdc++ version. That's a way less fixable problem.
Even if we do nothing else, we might want to set up a builder targeting scout now so that we will get errors if people try to use c++20 library features that it doesn't support.

Contributing.md

Minty-Meeo · 2022-08-26T04:44:22Z

After the minimum GCC version is increased, I have seen a couple of comments around the codebase that can be addressed by this, such as in ShaderGenCommon.h:

  // The second template argument is needed to avoid compile errors from ambiguity with multiple
  // enums with the same number of members in GCC prior to 8.  See https://godbolt.org/z/xcKaW1seW
  // and https://godbolt.org/z/hz7Yqq1P5

AdmiralCurtiss · 2022-09-08T18:15:45Z

So what's the status here?

Minty-Meeo · 2022-09-12T23:25:21Z

GCC 11 begins GCC's (partial) support for modules. Whether Dolphin Emulator should or should not begin using modules yet is open for debate. I personally want to begin experimenting with modules in the Common namespace in the near future.

Zopolis4 · 2022-09-12T23:28:10Z

I think GCC 12 is what I'd need for #11057, not sure about clang.

Minty-Meeo · 2022-09-12T23:35:48Z

Oh dang, you beat me to it! Well best of luck to you, then.

phire · 2022-09-13T00:16:33Z

Personally, I'm a little uneasy about pushing to gcc 12. Debian stable is only shipping with gcc 10.

Zopolis4 · 2022-09-18T22:57:05Z

I suppose we can merge this PR as is, then I can raise the minimum required versions in #11057.

OatmealDome · 2022-09-22T04:01:58Z

FYI, Valve has given us access to the ability to use a newer steam-runtime ("sniper", based on Debian 11), so Linux builds for Steam are no longer a problem.

CMakeLists.txt

AdmiralCurtiss · 2022-10-08T20:39:42Z

I'll ask again, what's the hold up here?

Minty-Meeo · 2022-10-10T17:41:30Z

I think there is a desire for a Steam Deck buildbot. Also, Android's buildbot still has an outdated stdlib, lacking <concepts> last I checked and also std::bit_cast (though it is not alone in that second one). I would also appreciate an update on this.

OatmealDome · 2022-10-10T19:12:32Z

The Steam Linux runtime is no longer a blocker for this. We've been given access by Valve to a newer version that is based off Debian 11.

JosJuice · 2022-10-10T19:19:08Z

Also, Android's buildbot still has an outdated stdlib, lacking last I checked and also std::bit_cast (though it is not alone in that second one).

The Android buildbot automatically fetches whatever SDK version is specified in the dolphin git repo. Though I suspect that not even the latest Android SDK has a recent enough stdlib for this...

Minty-Meeo · 2022-10-11T06:35:14Z

It is pretty simple to create a "Future" header for std::bit_cast thanks to how old the compiler built-in is for the three major compilers. See: #11153. This has also been how I worked around <concepts> being MIA for Android. IMO, this is the way forward until every supported platform gets up to speed with C++20.

Minty-Meeo · 2022-10-26T19:15:47Z

What is the prerequisite or milestone this PR is waiting on? Are we using C++20 or not? I'm sorry if this has already been answered in the IRC; I do not have anything set up to see what has been said while I am away.

CasualPokePlayer · 2023-02-19T10:09:14Z

Under the current Dolphin master (45b55f7), it seems GCC 10 or Clang 12 (or Apple Clang 13, as reported by Dentomologist on IRC) is required to build Dolphin. GCC 10 got required since 02a967f and Clang 12 (/Apple Clang 13) got required since 154cb4f (Clang 11 and back get unhappy about the template deduction here).

CMakeLists.txt

CasualPokePlayer · 2023-02-22T07:10:42Z

CMakeLists.txt

+
+# Enforce minimium compiler versions that support the c++20 features we use
+set (GCC_min_version 10)
+set (Clang_min_version 11)


As I noted here, Dolphin ends up requiring a newer Clang than this, due to 154cb4f. See "Class types in non-type template parameters" in https://en.cppreference.com/w/cpp/compiler_support.

Ok, I've bumped it to Clang 12 (Apple Clang 13)

CMakeLists.txt

We already have a minimum required version of MSVC

phire · 2023-02-23T02:37:10Z

Ok, I think I've addressed all review feedback.

shuffle2 · 2023-02-26T23:24:36Z

CMakeLists.txt

+set (Clang_min_version 12)
+set (AppleClang_min_version 13.0.0)
+set (min_xcode_version "13.0") # corrosponding xcode version for AppleClang_min_version
+set (MSVC_min_version 14.32)


i'd rather just keep this in pch.h (for msvc) so it's not needed to be updated in multiple places. these values are already not in sync with pch.h

Hmm... but the inverse also results in having versioning for different compilers split over different places.

I guess we can move it back when we deprecate the visual studio solutions.

OatmealDome · 2023-04-29T06:55:06Z

What's the status on this?

Pokechu22 reviewed Aug 10, 2022

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phire force-pushed the minimum_compilers branch from 1a4bd80 to 68d439a Compare August 10, 2022 07:44

phire changed the title ~~[RFC] Enforce minimum supported versions of GCC and Clang~~ Enforce minimum supported versions of GCC and Clang Aug 10, 2022

shuffle2 reviewed Aug 10, 2022

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Zopolis4 mentioned this pull request Sep 6, 2022

Introducing: Common Concepts and Future CppLibConcepts #11034

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AdmiralCurtiss reviewed Sep 23, 2022

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OatmealDome mentioned this pull request Feb 19, 2023

Update minimum GCC version in cmake enforcement to 10 #11585

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CasualPokePlayer reviewed Feb 22, 2023

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phire force-pushed the minimum_compilers branch from 68d439a to 5251a05 Compare February 23, 2023 01:18

Enforce minimum supported versions of GCC and Clang

f34a09b

We already have a minimum required version of MSVC

phire force-pushed the minimum_compilers branch from 1f123db to f34a09b Compare February 23, 2023 02:18

Bump requried Clang to 12 (AppleClang 13.0.0)

a306da2

phire force-pushed the minimum_compilers branch from 4b8bbf8 to a306da2 Compare February 23, 2023 02:29

shuffle2 reviewed Feb 26, 2023

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OatmealDome mentioned this pull request Apr 28, 2023

Enable BCn texture support on iOS where available #11757

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AdmiralCurtiss merged commit b514df1 into dolphin-emu:master May 1, 2023

Medard22 mentioned this pull request Mar 11, 2024

Enforce minimum supported versions of GCC and Clang Medard22/Dolphin-MMJR2-VBI#276

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Enforce minimum supported versions of GCC and Clang #10969

Enforce minimum supported versions of GCC and Clang #10969

phire commented Aug 10, 2022 •

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Enforce minimum supported versions of GCC and Clang #10969

Enforce minimum supported versions of GCC and Clang #10969

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phire commented Aug 10, 2022 • edited

Why not feature detection?

What versions?

phire commented Aug 10, 2022

endrift commented Aug 10, 2022

phire commented Aug 10, 2022

phire commented Aug 10, 2022

OatmealDome commented Aug 10, 2022

phire commented Aug 10, 2022

Minty-Meeo commented Aug 26, 2022

AdmiralCurtiss commented Sep 8, 2022

Minty-Meeo commented Sep 12, 2022

Zopolis4 commented Sep 12, 2022

Minty-Meeo commented Sep 12, 2022

phire commented Sep 13, 2022

Zopolis4 commented Sep 18, 2022 • edited

OatmealDome commented Sep 22, 2022 • edited

AdmiralCurtiss commented Oct 8, 2022

Minty-Meeo commented Oct 10, 2022

OatmealDome commented Oct 10, 2022

JosJuice commented Oct 10, 2022

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