Build errors on Linux for `x86_32` and `arm64`

[Joy-less]

Godot version

4.4.1-stable

godot-cpp version

4.4.1-stable

System information

Compiling on Linux Ubuntu 22.04 (GitHub Actions)

Issue description

This library builds correctly for most platforms & architectures but fails for Linux x86_32 and arm64. Note that both Linux x86_64 and arm32 are successful.

Error with Linux x86_32:

Compiling godot-cpp/src/core/memory.cpp ...
In file included from godot-cpp/include/godot_cpp/core/memory.hpp:34,
                 from godot-cpp/src/core/memory.cpp:31:
/usr/include/c++/11/cstddef:49:10: fatal error: bits/c++config.h: No such file or directory
   49 | #include <bits/c++config.h>
      |          ^~~~~~~~~~~~~~~~~~
compilation terminated.

This StackOverflow question seems to match: https://stackoverflow.com/questions/4643197/missing-include-bits-cconfig-h-when-cross-compiling-64-bit-program-on-32-bit

Error with Linux arm64:

Compiling godot-cpp/src/core/memory.cpp ...
cc1plus: error: bad value ('armv8-a') for '-march=' switch
cc1plus: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids alderlake bonnell atom silvermont slm goldmont goldmont-plus tremont knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-[20](https://github.com/jsonh-org/JsonhGdextension/actions/runs/14551688442/job/40823637458#step:5:21)00 nano-3000 nano-x2 eden-x4 nano-x4 k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 btver1 btver2 native

This StackOverflow question seems to match: https://stackoverflow.com/questions/40142803/cc1-error-bad-value-armv8-a-for-march-switch

This is producing build errors for the pull request in godot-cpp template: godotengine/godot-cpp-template#89

Steps to reproduce

Build this library targeting either linux x86_32 or linux arm64 architectures.

Minimal reproduction project

godot-cpp template: https://github.com/godotengine/godot-cpp-template

[dsnopek]

Do you have the toolchains for (cross-)compiling to arm64 and x86_32 installed?

Based on this error message:

Compiling godot-cpp/src/core/memory.cpp ...
cc1plus: error: bad value ('armv8-a') for '-march=' switch
cc1plus: note: valid arguments to '-march=' switch are: nocona core2 nehalem corei7 westmere sandybridge corei7-avx ivybridge core-avx-i haswell core-avx2 broadwell skylake skylake-avx512 cannonlake icelake-client rocketlake icelake-server cascadelake tigerlake cooperlake sapphirerapids alderlake bonnell atom silvermont slm goldmont goldmont-plus tremont knl knm x86-64 x86-64-v2 x86-64-v3 x86-64-v4 eden-x2 nano nano-1000 nano-[20](https://github.com/jsonh-org/JsonhGdextension/actions/runs/14551688442/job/40823637458#step:5:21)00 nano-3000 nano-x2 eden-x4 nano-x4 k8 k8-sse3 opteron opteron-sse3 athlon64 athlon64-sse3 athlon-fx amdfam10 barcelona bdver1 bdver2 bdver3 bdver4 znver1 znver2 znver3 btver1 btver2 native

... it seems like you're using a compiler toolchain for x86_64.

Perhaps you're using a host system that is x86_64, and wanting to cross-compile to arm64, but don't have the necessary toolchain installed? Or, at the very least, scons doesn't seem to be finding it?

[Joy-less]

@dsnopek This is the relevant part of the workflow file:

{ platform: linux, arch: x86_64, os: ubuntu-22.04 },
{ platform: linux, arch: x86_32, os: ubuntu-22.04 }, # BROKEN
{ platform: linux, arch: arm64, os: ubuntu-22.04 }, # BROKEN
{ platform: linux, arch: arm32, os: ubuntu-22.04 },
{ platform: windows, arch: x86_64, os: windows-latest },
{ platform: windows, arch: x86_32, os: windows-latest },
{ platform: windows, arch: arm64, os: windows-latest },
{ platform: macos, arch: universal, os: macos-latest },
{ platform: android, arch: x86_64, os: ubuntu-22.04 },
{ platform: android, arch: x86_32, os: ubuntu-22.04 },
{ platform: android, arch: arm64, os: ubuntu-22.04 },
{ platform: android, arch: arm32, os: ubuntu-22.04 },
{ platform: ios, arch: arm64, os: macos-latest },
{ platform: web, arch: wasm32, os: ubuntu-22.04 },

According to GitHub Actions, these are the architectures:

Looks like it would be possible to use an arm64 version of Linux but there's no x86_32 versions.

How would you go about installing the necessary toolchain?

[Joy-less]

I can confirm that compiling with ubuntu-24.04-arm resolves the linux arm64 issue. Which just leaves linux x86_32.

[dsnopek]

I can confirm that compiling with ubuntu-24.04-arm resolves the linux arm64 issue. Which just leaves linux x86_32.

The StackOverflow article you linked above recommends this command:

apt-get install gcc-multilib g++-multilib

Have you tried running that on GitHub actions?

[Joy-less]

I can confirm that compiling with ubuntu-24.04-arm resolves the linux arm64 issue. Which just leaves linux x86_32.

The StackOverflow article you linked above recommends this command:

apt-get install gcc-multilib g++-multilib

Have you tried running that on GitHub actions?

I'm not sure how or where to run this to be honest.

[dsnopek]

You could maybe add code like this (untested):

- name: Install multilib support
  if: matrix.target.platform == 'linux' && matrix.target.arch == 'x86_32'
  run: sudo apt-get update && sudo apt-get install -y gcc-multilib g++-multilib

... to somewhere around here?

In any case, this issue doesn't seem to be a problem with godot-cpp, I don't think there's going to be anything to fix here. This all seems to be a matter of getting the machine that's doing the building setup correctly

[Joy-less]

You could maybe add code like this (untested):

- name: Install multilib support
  if: matrix.target.platform == 'linux' && matrix.target.arch == 'x86_32'
  run: sudo apt-get update && sudo apt-get install -y gcc-multilib g++-multilib

... to somewhere around here?

In any case, this issue doesn't seem to be a problem with godot-cpp, I don't think there's going to be anything to fix here. This all seems to be a matter of getting the machine that's doing the building setup correctly

Thanks, it works. Closing.