Multi-arch CI

[philberty]

travis offers CI for multiple architectures, we should make an automation for things in master to do a non bootstrap build and run the test suite. Something like this could be the starting point:

language: c

arch:
  - amd64
  - ppc64le
  - s390x
  - arm64
  
os: linux

before_install:
  - sudo apt-get install -y automake autoconf libtool autogen bison flex libgmp3-dev libmpfr-dev libmpc-dev build-essential gcc-multilib g++-multilib dejagnu

script:
  - mkdir -p gccrs-build;
  - cd gccrs-build; ../configure --enable-languages=rust --disable-bootstrap --enable-multilib; make -j $(nproc); make check-rust
  - cd gccrs-build; \
           if grep "# of unexpected" gcc/testsuite/rust/rust.sum;\
           then \
              echo "some tests are not correct"; \
              exit 1; \
            else \
              exit 0; \
            fi

[bjorn3]

https://blog.travis-ci.com/2020-11-02-travis-ci-new-billing

For those of you who have been building on public repositories (on travis-ci.com, with no paid subscription), we will upgrade you to our trial (free) plan with a 10K credit allotment (which allows around 1000 minutes in a Linux environment).

With this they mean downgrade, not upgrade. The C/C++ CI job takes ~25min on GHA and the GCC Bootstrap Build job takes ~1h. Looking at just the C/C++ CI job for 4 archs that would be 100 minutes per merge. At a cap of 1000 minutes per month that would be just 10 merges per month.

[philberty]

I would be tempted to cover the charges here but probably limited to something like $50 a month. Or we could make this a manual kick off job for anytime we make a tag of the repo or something.

[bjorn3]

For ppc64le and arm64 using qemu would work, right? It could either be compiling gcc inside qemu or cross-compiling gcc for the target and then running the test suite in qemu with user mode emulation. This is what rustc does on CI for certain architectures. This leaves s390x though for which qemu supposedly doesn't yet have much support.

[philberty]

Not a bad shout I wonder is it possible to post build badges etc. I do have a fairly decent system on digital ocean that we might be able to reuse for this.

[hoall]

Hi,

I am just interested in the project without knowing much about your setup. You already use GitHub actions. I came across https://github.com/marketplace/actions/run-on-archlinuxarm for running on multiple architectures but never used it. Maybe it's worth a look

[mathstuf]

This repo is also likely of interest here.

[philberty]

@hoall thanks for point this out it looks really interesting. I also think the rustc project is using some kind of qemu system with github actions to perform this type of test. Sorry I missed your comment until now this looks really cool ! :)