Build error: llvmPackages.libunwind

Help
1

I’m having trouble building a package in cross-compilation mode, but the same package seems to build with nix build:

in nixpkgs on commit 32a4e87942101f1c9f9865e04dc3ddb175f5f32e (top of nixos-25.05, same as the one I use with flakes that encounter a build error) this command works:
nix build ".#pkgsCross.musl64.llvmPackages.libunwind"

anywhere (I don’t understand where does the package definition comes in this case) these commands don’t:

nix-shell -p libunwind --arg crossSystem "{ config = \"x86_64-unknown-linux-musl\"; useLLVM = true; isStatic = true; }"
nix-shell -p llvmPackages.libunwind --arg crossSystem "{ config = \"x86_64-unknown-linux-musl\"; useLLVM = true; isStatic = true; }"

I have the following questions then: how do I choose what channel does nix-shell take packages from if I start it with package parameter? Is this pkgsCross.musl64.llvmPackages.libunwind a correct target to try building on this error? It feels like isStatic is important here, but I can’t understand how to pass it to nix build to open an issue in nixpkgs

I also don’t understand how to override llvmPackages.libunwind that seems to come from stdenv, but that’s a different story.

This happens on x86_64-linux and aarch64-darwin build machines

Relevant log from builder:

error: builder for '/nix/store/wanl0kzsjpiiccw2qh0p9xqp87rchw75-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv' failed with exit code 1;
       last 25 log lines:
       > clang++: warning: argument unused during compilation: '-rtlib=compiler-rt' [-Wunused-command-line-argument]
       > [10/10] Linking C static library lib/libunwind.a
       > Running phase: installPhase
       > install flags: -j10 install
       > [0/1] Install the project...
       > -- Install configuration: "Release"
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/__libunwind_config.h
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/libunwind.h
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/libunwind.modulemap
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/mach-o/compact_unwind_encoding.h
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind_arm_ehabi.h
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind_itanium.h
       > -- Installing: /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind.h
       > -- Installing: /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.a
       > Running phase: fixupPhase
       > shrinking RPATHs of ELF executables and libraries in /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7
       > checking for references to /private/tmp/nix-build-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv-2/ in /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7...
       > patching script interpreter paths in /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7
       > stripping (with command x86_64-unknown-linux-musl-strip and flags -S) in  /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib
       > shrinking RPATHs of ELF executables and libraries in /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev
       > checking for references to /private/tmp/nix-build-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv-2/ in /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev...
       > patching script interpreter paths in /nix/store/488xbnlh769id2xbb08jf0768wiflqka-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev
       > ERROR: noBrokenSymlinks: the symlink /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libgcc_s.so.1 points to a missing target: /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.so
       > ERROR: noBrokenSymlinks: the symlink /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libgcc_s.so points to a missing target: /nix/store/yzinfvjxzyvg8c7ns47y2xmq5vbsklng-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.so
       > ERROR: noBrokenSymlinks: found 2 dangling symlinks, 0 reflexive symlinks and 0 unreadable symlinks
       For full logs, run:
         nix log /nix/store/wanl0kzsjpiiccw2qh0p9xqp87rchw75-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv

and

error: builder for '/nix/store/37c7kf9nxrp464jqnfgj3qs82x77m7cf-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv' failed with exit code 1;
       last 25 log lines:
       > clang++: warning: argument unused during compilation: '-rtlib=compiler-rt' [-Wunused-command-line-argument]
       > [10/10] Linking C static library lib/libunwind.a
       > Running phase: installPhase
       > install flags: -j10 install
       > [0/1] Install the project...
       > -- Install configuration: "Release"
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/__libunwind_config.h
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/libunwind.h
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/libunwind.modulemap
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/mach-o/compact_unwind_encoding.h
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind_arm_ehabi.h
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind_itanium.h
       > -- Installing: /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev/include/unwind.h
       > -- Installing: /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.a
       > Running phase: fixupPhase
       > shrinking RPATHs of ELF executables and libraries in /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7
       > checking for references to /private/tmp/nix-build-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv-2/ in /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7...
       > patching script interpreter paths in /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7
       > stripping (with command x86_64-unknown-linux-musl-strip and flags -S) in  /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib
       > shrinking RPATHs of ELF executables and libraries in /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev
       > checking for references to /private/tmp/nix-build-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv-2/ in /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev...
       > patching script interpreter paths in /nix/store/xgfcb37mdzp6ilcw6sc2h9av5zzxpy2r-libunwind-static-x86_64-unknown-linux-musl-19.1.7-dev
       > ERROR: noBrokenSymlinks: the symlink /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libgcc_s.so.1 points to a missing target: /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.so
       > ERROR: noBrokenSymlinks: the symlink /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libgcc_s.so points to a missing target: /nix/store/c0lclm5kvzamwmqsb9dsac02943x4zbm-libunwind-static-x86_64-unknown-linux-musl-19.1.7/lib/libunwind.so
       > ERROR: noBrokenSymlinks: found 2 dangling symlinks, 0 reflexive symlinks and 0 unreadable symlinks
       For full logs, run:
         nix log /nix/store/37c7kf9nxrp464jqnfgj3qs82x77m7cf-libunwind-static-x86_64-unknown-linux-musl-19.1.7.drv
2

I’m guessing, I should try something like pkgsCross.musl64.pkgsStatic.llvmPackages.libunwind? Will try and write back once I will be able to do that

3

This will be fixed by llvmPackages.libunwind: condition doFakeLibgcc on !stdenv.hostPlatform.isStatic by pwaller · Pull Request #417354 · NixOS/nixpkgs · GitHub

2 Likes
4

Thanks for a reply, that’s great to hear.

In the meantime I may hope that this breaks only the tests, but how should I go with replacing libunwind in llvmPackages with an earlier version? I’ve tried to override it in different places to no avail

Of course, we can also go with old nixpkgs and only pick new dependencies we need from new nixpkgs in the meantime.