Issue when compiling on CI: Must not detect more than one architecture

[7sharp9]

Hi, Im getting an error when running on GI while building a mac architecture:
|

Run cmake --build Builds --config Release --parallel 4
  cmake --build Builds --config Release --parallel 4
  shell: /bin/bash --noprofile --norc -e -o pipefail {0}
  env:
    BUILD_TYPE: Release
    BUILD_DIR: Builds
    DISPLAY: :0
    HOMEBREW_NO_INSTALL_CLEANUP: 1
    SCCACHE_GHA_ENABLED: true
    SCCACHE_CACHE_MULTIARCH: 1
    IPP_DIR: C:\Program Files (x86)\Intel\oneAPI\ipp\latest\lib\cmake\ipp
    MD_APPLE_SDK_ROOT: /Applications/Xcode_16.2.app
    SCCACHE_PATH: /Users/runner/hostedtoolcache/sccache/0.9.1/arm64/sccache
    ACTIONS_CACHE_URL: https://acghubeus1.actions.githubusercontent.com/gv5Ziv9LRLvK3r7wA0NxS1PnmS1Rp48kYoB753XWAcX7CS7FRq/
    ACTIONS_RUNTIME_TOKEN: ***
[0/2] Re-checking globbed directories...
[1/620] Building CXX object _deps/highway-build/CMakeFiles/hwy.dir/hwy/aligned_allocator.cc.o
FAILED: _deps/highway-build/CMakeFiles/hwy.dir/hwy/aligned_allocator.cc.o 
sccache /Applications/Xcode_16.2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++ -DHWY_STATIC_DEFINE -DNDEBUG -DTOOLCHAIN_MISS_ASM_HWCAP_H -DTOOLCHAIN_MISS_SYS_AUXV_H -I/Users/runner/work/StudioStandard/StudioStandard/Builds/_deps/highway-src -O3 -DNDEBUG -O3 -mcpu=apple-m1 -ffp-contract=fast -std=c++17 -arch arm64 -arch x86_64 -isysroot /Applications/Xcode_16.2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX15.2.sdk -mmacosx-version-min=11.0 -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -Wno-builtin-macro-redefined -D__DATE__=\"redacted\" -D__TIMESTAMP__=\"redacted\" -D__TIME__=\"redacted\" -fmerge-all-constants -Wall -Wextra -Wconversion -Wsign-conversion -Wvla -Wnon-virtual-dtor -Wcast-align -Wfloat-overflow-conversion -Wfloat-zero-conversion -Wfor-loop-analysis -Wgnu-redeclared-enum -Winfinite-recursion -Wself-assign -Wstring-conversion -Wtautological-overlap-compare -Wthread-safety-analysis -Wundefined-func-template -fno-cxx-exceptions -fno-slp-vector
In file included from /Users/runner/work/StudioStandard/StudioStandard/Builds/_deps/highway-src/hwy/aligned_allocator.cc:16:
In file included from /Users/runner/work/StudioStandard/StudioStandard/Builds/_deps/highway-src/hwy/aligned_allocator.h:32:
In file included from /Users/runner/work/StudioStandard/StudioStandard/Builds/_deps/highway-src/hwy/base.h:29:
/Users/runner/work/StudioStandard/StudioStandard/Builds/_deps/highway-src/hwy/detect_compiler_arch.h:329:2: error: "Must not detect more than one architecture"
  329 | #error "Must not detect more than one architecture"
      |  ^
1 error generated.

Did I miss something I need to do on the CI?

[johnplatts]

The issue is that the __x86_64__ and __aarch64__ macros are both defined, and only one of the two macros should be defined.

The Highway C++ files have to be compiled twice if you want to target for both x86_64 and ARM64 on macOS, once for x86_64 and once for ARM64.

One way to configure CMake to build for both x86_64 and ARM64 is to pass in the -G Xcode -DCMAKE_OSX_ARCHITECTURES="arm64;x86_64" options to cmake when configuring to build Google Highway for macOS on both x86_64 and ARM64. The -G Xcode -DCMAKE_OSX_ARCHITECTURES="arm64;x86_64" options will cause CMake to generate XCode project files that will target both x86_64 and ARM64.

If Google Highway is configured to be built for both x86_64 and ARM64 using XCode project files, cmake --build will invoke xcodebuild, which will take care of invoking the C++ compiler twice for each Google Highway C++ file, once for x86_64 and once for ARM64, which should fix the errors that you are encountering with building for both x86_64 and ARM64 on macOS.

[johnplatts]

@7sharp9 I did successfully build Google Highway for macOS for both x86_64 and ARM64 using a GitHub Workflow, and the results of that workflow run can be found at https://github.com/johnplatts/jep_google_highway/actions/runs/13345004943/job/37274387258.

Here is the GitHub workflow that I used to build Google Highway for macOS (and this workflow is not part of the Google Highway master branch):
https://github.com/johnplatts/jep_google_highway/blob/793e5c9cbef72a6984fd7dec934bbbeaa5143a13/.github/workflows/build_test.yml

[7sharp9]

@johnplatts Im guessing the workflow Im using has never built highway before. When I build locally my cmake contains:

set(CMAKE_OSX_ARCHITECTURES arm64 x86_64)

And highway is pulled in via CPMAddPackage:

CPMAddPackage(
        NAME highway
        GITHUB_REPOSITORY google/highway
        GIT_TAG d547f91bc94deffe8aafa044934e4fd78354493f
        OPTIONS "HWY_ENABLE_EXAMPLES OFF" "HWY_ENABLE_INSTALL OFF" "HWY_ENABLE_TESTS OFF" "HWY_FORCE_STATIC_LIBS ON"

That succesfully created a universal lib for highway etc an my local machine.

I'll have a look at the workflow you provided, thanks!

[7sharp9]

@johnplatts I think it's to do with the -G Xcode with Ninja it fails with the error I mentioned above but -G Xcode doesnt. It seems to be really tricky to get per architecture compiler optimisations. e.g
Setting x64 specific: -march=x86-64-v2 -maes -mpclmul
And the same for arm: -mcpu=apple-m1 -ffp-contract=fast

I trie the -Xarch_x86_64 but they dont seem to work but there is an Xcode specific way to do this I think.