🐛 Bug Report: Fails to build on WolfiOS with clang-17 (failed: error executing CppLink command)

[willswire]

I am trying to contribute workerd as a package to WolfiOS here. I've included the necessary build dependencies:

environment:
  contents:
    packages:
      - bash
      - bazelisk
      - bazelisk-default
      - binutils
      - build-base
      - busybox
      - clang-17
      - clang-17-dev
      - gnutar
      - libtool
      - llvm-libunwind-17
      - llvm-libcxx-17
      - llvm-libcxx-17-dev
      - llvm-libcxxabi-17
      - llvm-lld-17
      - llvm17
      - llvm17-dev
      - posix-libc-utils
      - python3-dev
      - tcl

However I am getting the following error:

ERROR: /home/build/.cache/bazel/_bazel_root/79a1bfc8c8b5b6a6d226b38d072f165b/external/capnp-cpp/src/capnp/BUILD.bazel:139:10: Linking external/capnp-cpp/src/capnp/capnpc-c++ [for tool] failed: (Exit 1): clang-17 failed: error executing CppLink command (from target @@capnp-cpp//src/capnp:capnpc-c++)

Potentially related issues:

• 🐛 Bug Report: Fails to build on Arch Linux with clang-16 #1689
• [Bazel CI] Error failed executing CppLink command  bazelbuild/bazel#24486

[fhanau]

Can you provide the full error output for this? The actual error message from the linker/clang driver should be listed below the ERROR line you included here.
In terms of dependencies, I'm not familiar with your package manager but for Debian/Ubuntu installing a libc++abi-<version>-dev package is required, I'm not sure if that will be installed as a dependency of the packages you have listed. Looking at the CI build scripts, there's also libc++abi1-16 and libc++1-16 packages being installed. If the link error message is libc++-related, that or something similar should be responsible here.

[willswire]

I figured it out! I just had to add libstdc++-6 and libstdc++-6-dev along with the following build flags:

bazel build \
 --config=thin-lto \
 --linkopt='-lc++' --linkopt='-lm' \
 --host_linkopt='-lc++' --host_linkopt='-lm' \
 //src/workerd/server:workerd

[fhanau]

Note that the workerd build tries to statically link its binaries with libc++ and libgcc by passing --linkopt='-l:libc++.a' --linkopt='-lm' --linkopt='-static-libgcc' in .bazelrc. With that passing -lm manually should not be needed. I assume with your changes libc++ is being linked dynamically instead, which might work around static libc++ not being installed? Either way, glad it's working for you now.