Enable RISC-V build & test

[alexsifivetw]

Enable RISC-V build & test.

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[alexsifivetw]

Seems like the docker image doesn’t run risc-v toolchain & qemu installation. Can any one help me?

zstd/.circleci/images/primary/Dockerfile

Lines 10 to 16 in afcd5da

	# TODO: Use apt to install prebuilt risc-v toolchain & qemu in the future
	RUN sudo wget https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/2023.07.05/riscv64-glibc-ubuntu-20.04-llvm-nightly-2023.07.05-nightly.tar.gz
	RUN sudo tar -C /opt -zxvf riscv64-glibc-ubuntu-20.04-llvm-nightly-2023.07.05-nightly.tar.gz
	RUN sudo rm riscv64-glibc-ubuntu-20.04-llvm-nightly-2023.07.05-nightly.tar.gz
	RUN sudo ln -s -f /opt/riscv/bin/clang-16 /usr/bin/riscv64-unknown-linux-gnu-clang
	RUN sudo ln -s -f /opt/riscv/bin/llvm-ar /usr/bin/llvm-ar
	RUN sudo ln -s -f /opt/riscv/bin/qemu-riscv64 /usr/bin/qemu-riscv64

[Cyan4973]

Dependencies in general, and on docker images specifically, are to be avoided when practical.
I would rather prefer to rely on standard apt packages for CI.
I could get it to run risc-v tests properly in another project.

[alexsifivetw]

I would rather prefer to rely on standard apt packages for CI.

I agree. We can now use apt to install riscv-gcc-11, but only gcc 13 and later versions support RISC-V RVV.
We use wget to get latest RISC-V toolchain & QEMU because of our plane for RVV-optimization for zstd.

We could use apt to install toolchain, and use __riscv_v macro to protect RVV-optimized codes.
This means that the RVV-optimized code would only be enabled when the compiler supports RVV.

However, get RVV-supported toolchain & qemu via apt could take long time.

[alexsifivetw]

Do you accept installing the toolchain via PPA?

[Cyan4973]

Do you accept installing the toolchain via PPA?

It depends on the PPA,
but in this particular case,
I'm not sure if there is such a need.

RISC-V qemu tests are working fine on Github CI using only regular apt in another project :
https://github.com/Cyan4973/xxHash/blob/dev/.github/workflows/ci.yml#L386

[alexsifivetw]

Hi, I apologize for the late reply.
RISC-V is a young and modern platform. The RISC-V spec, intrinsics, toolchain ... etc, change frequently. Therefore, we need to use the nightly prebuilt toolchain and install it using wget.
Would you accept this wget method and update the recipe for Docker image?

[Cyan4973]

Let's keep it around.
I'll look at it when I get the time.