Can't build crtbegin.c on s390x & arm64 for wasm32

[sylvestre]

Recent regression on s390x & arm64:

cd /build/source/build-wasm/compiler-rt-wasm32 && /build/source/build-llvm/tools/clang/stage2-bins/bin/clang -O2 -DNDEBUG -g1 -fstack-protector-strong -Wformat -Werror=format-security -Wno-unused-command-line-argument -Wdate-time -D_FORTIFY_SOURCE=2 --target=wasm32-unknown-unknown -fno-lto -std=c11 -DEH_USE_FRAME_REGISTRY -fPIC -Wno-pedantic --target=wasm32-unknown-unknown -o /build/source/build-wasm/compiler-rt-wasm32/lib/wasi/clang_rt.crtbegin-wasm32.o -c /build/source/compiler-rt/lib/builtins/crtbegin.c
/build/source/compiler-rt/lib/builtins/crtbegin.c:77:2: error: "crtbegin without .init_fini array unimplemented for this architecture"
   77 | #error "crtbegin without .init_fini array unimplemented for this architecture"
      |  ^
/build/source/compiler-rt/lib/builtins/crtbegin.c:134:2: error: "crtbegin without .init_fini array unimplemented for this architecture"
  134 | #error "crtbegin without .init_fini array unimplemented for this architecture"
      |  ^
2 errors generated.

Log:
https://llvm-jenkins.debian.net/job/llvm-toolchain-bionic-binaries/architecture=s390x,distribution=bionic,label=s390x/1153/console

Seems to be caused by:
https://reviews.llvm.org/D153989

@petrhosek rings a bell?

[petrhosek]

Thanks for the heads up, I have reverted the change while I'm investigating this.

[petrhosek]

It looks like https://llvm-jenkins.debian.net/job/llvm-toolchain-bionic-binaries/architecture=s390x,distribution=bionic,label=s390x/ doesn't set CMAKE_SYSTEM_NAME when building for wasm32, so the CMAKE_SYSTEM_NAME will be inferred as Linux causing this branch to be taken:

llvm-project/compiler-rt/cmake/builtin-config-ix.cmake

Line 228 in dae9d1b

if (OS_NAME MATCHES "Linux" AND NOT LLVM_USE_SANITIZER)

Would it be possible to set CMAKE_SYSTEM_NAME to either WASI or Generic when targeting wasm32?

The title also mentions s390x and arm64 but I don't see those in the log you linked. Do you have a link to the build failures for those architectures? I expect it's going to be the same issue but I want to double check.

[sylvestre]

it fails for every arch actually.
See amd64 here: https://llvm-jenkins.debian.net/job/llvm-toolchain-bionic-binaries/architecture=amd64,distribution=bionic,label=amd64/1153/consoleFull

[petrhosek]

It looks these are different builders running on different architectures, but it's always the wasm32-unknown-unknown target that's failing, so I still think it's the CMAKE_SYSTEM_NAME issue I described.

Where are these bulders configured? I couldn't find them in https://github.com/llvm/llvm-zorg. Can we set CMAKE_SYSTEM_NAME for the wasm32-unknown-unknown compiler-rt build?

[sylvestre]

sorry, s390 and arm64 are the host machines. The target is wasm32

Configuration is here:
https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/commits/snapshot/debian/rules

[petrhosek]

Thanks, I think we need to set -DCMAKE_SYSTEM_NAME=Generic at https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/blob/snapshot/debian/rules#L798-L821. Is that a change you can make or do you want me to send a merge request?

[sylvestre]

don't bother, thanks :)
I will try

[petrhosek]

This appears to be resolved.