[LoongArch64] Cross compilation instructions.

[kant2002]

Right now upstream compilers does not support LoongArch64. What steps should I take in order to be able compile CoreCLR with loongarch architecture. I will work on repository with #62889 applied.

Question is how to build rootfs myself? If tools would come as blob, how can I try to recreate GCC/Clang and other tools there?

/cc @shushanhf and maybe of interest to @am11

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Issue Details

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Right now upstream compilers does not support LoongArch64. What steps should I take in order to be able compile CoreCLR with loongarch architecture. I will work on repository with #62889 applied.

Question is how to build rootfs myself? If tools would come as blob, how can I try to recreate GCC/Clang and other tools there?

/cc @shushanhf and maybe of interest to @am11

Author:	kant2002
Assignees:	-
Labels:	area-Infrastructure, untriaged, arch-loongarch64
Milestone:	-

[am11]

Right now upstream compilers does not support LoongArch64.

Not just that; both gcc and llvm loongarch64 patch series are currently under review. Here are the preface mails of each:

• https://lists.llvm.org/pipermail/llvm-dev/2021-December/154371.html
• https://gcc.gnu.org/pipermail/gcc-patches/2021-November/585555.html

I think it is too early for a cross-compiler toolchain setup. If it was me, I'd at least wait for those patches to be reviewed and merged in their respective mainlines.

[kant2002]

What I want to test right now, is to cross check using native tooling, how CoreCLR compiles for LoongArch64 even without public compilers. I do not think I can contribute to Runtime these work, but gradually I think this can be interesting stress test for LoongArch64 compilers. I tag @am11 only because maybe it would be interesting to lurk at this work for you. But I expect most in this from @shushanhf

At least would be great to know where to start.

[kant2002]

At least for building on hardware you can use this branch https://github.com/kant2002/runtime/tree/kant/loongarch64-rootfs

[shushanhf]

Right now upstream compilers does not support LoongArch64.

Not just that; both gcc and llvm loongarch64 patch series are currently under review. Here are the preface mails of each:

• https://lists.llvm.org/pipermail/llvm-dev/2021-December/154371.html
• https://gcc.gnu.org/pipermail/gcc-patches/2021-November/585555.html

I think it is too early for a cross-compiler toolchain setup. If it was me, I'd at least wait for those patches to be reviewed and merged in their respective mainlines.

Hi, @am11 @kant2002
I think it's time to try adding LA64's CI.
What should I do ? I can supply some LA64's tools.

[am11]

LA64 CI was added. It uses the cross image which you can use locally, e.g.:

$ cd runtime
$ docker run --rm -e ROOTFS_DIR=/crossrootfs/loongarch64 -v$(pwd):/runtime -w /runtime \
    mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net10.0-cross-loongarch64 \
    ./build.sh clr+libs -cross -a loongarch64