Comment by Jonathan Hemi (JIRA)

CodaFi (JIRA User) would really appreciate your eyes on this if you get a a chance.

Could you provide the link line being emitted by clang? If that doesn’t contain a suitable -platform_version it will fall back to the host’s platform which id what it seems to be doing here.

Comment by Jonathan Hemi (JIRA)

I think this is everything, also attached the entire folders since they're small.

– Check for working C compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang
– Check for working C compiler: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang - broken
CMake Error at /usr/local/Cellar/cmake/3.19.3/share/cmake/Modules/CMakeTestCCompiler.cmake:66 (message):
{{ The C compiler}}

"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"

is not able to compile a simple test program.

It fails with the following output:

Change Dir: /Users/jonathan/try/sw/host-build/Ninja-Release/cmark-iphoneos-arm64/CMakeFiles/CMakeTmp

{{ Run Build Command(s):/usr/local/bin/ninja cmTC_51f01 && [1/2][ 50%][0.034s] Building C object CMakeFiles/cmTC_51f01.dir/testCCompiler.c.o}}
{{ [2/2][100%][0.093s] Linking C executable cmTC_51f01}}
{{ FAILED: cmTC_51f01 }}
{{ : && /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -Wno-unknown-warning-option -Werror=unguarded-availability-new -arch arm64 -target arm64-apple-iphoneos14.0 -fno-stack-protector -arch arm64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS14.3.sdk -Wl,-search_paths_first -Wl,-headerpad_max_install_names CMakeFiles/cmTC_51f01.dir/testCCompiler.c.o -o cmTC_51f01 && :}}
{{ clang: warning: argument unused during compilation: '-arch arm64' [-Wunused-command-line-argument]}}
{{ clang: warning: argument unused during compilation: '-arch arm64' [-Wunused-command-line-argument]}}
{{ ld: warning: ignoring file CMakeFiles/cmTC_51f01.dir/testCCompiler.c.o, building for iOS-x86_64 but attempting to link with file built for unknown-unsupported file format ( 0x7F 0x45 0x4C 0x46 0x02 0x01 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 )}}
{{ ld: warning: ignoring file /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS14.3.sdk/usr/lib/libSystem.tbd, missing required architecture x86_64 in file /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS14.3.sdk/usr/lib/libSystem.tbd (4 slices)}}
{{ Undefined symbols for architecture x86_64:}}
{{ "_main", referenced from:}}
{{ implicit entry/start for main executable}}
{{ ld: symbol(s) not found for architecture x86_64}}
{{ clang: error: linker command failed with exit code 1 (use -v to see invocation)}}
{{ clang: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation)}}
{{ ninja: build stopped: subcommand failed.}}

{{ }}

CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
{{ CMakeLists.txt:2 (project)}}

– Configuring incomplete, errors occurred!
See also "/Users/jonathan/try/sw/host-build/Ninja-Release/cmark-iphoneos-arm64/CMakeFiles/CMakeOutput.log".
See also "/Users/jonathan/try/sw/host-build/Ninja-Release/cmark-iphoneos-arm64/CMakeFiles/CMakeError.log".
ERROR: command terminated with a non-zero exit status 1, aborting

ERROR: command terminated with a non-zero exit status 1, aborting

Comment by Jonathan Hemi (JIRA)

But the host is macOS, isn't the ELF a weird outcome?

Perhaps the issue is the old-style triple. Try `arm64-apple-ios14.0`. You may need to reconfigure your build.

Comment by Jonathan Hemi (JIRA)

No luck. It will not create the output folders, failing with:

[/Users/jonathan/try/sw/swift/utils/build-script] NOTE: Using toolchain default
+ /usr/libexec/PlistBuddy -c 'Print :SupportedTargets:macosx:Archs' /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk/SDKSettings.plist
+ mkdir -p /Users/jonathan/try/sw/host-build/Ninja-Release
ERROR: unknown target: arm64-apple-ios14.0
ERROR: command terminated with a non-zero exit status 1, aborting

The error is coming from here and the expected triple format is parsed here (seems iphoneos-arm64 is the only valid option).

Comment by Jonathan Hemi (JIRA)

I think I can distill it to the simplest clang invocation of a 'return 0' c program:

~ clang -arch arm64 -target arm64-apple-iphoneos14.0 ./hello.c
ld: warning: ignoring file /var/folders/7f/tdyh3rw96rq2nf0w95btmb4h0000gn/T/hello-515e59.o, building for macOS-x86_64 but attempting to link with file built for unknown-unsupported file format ( 0x7F 0x45 0x4C 0x46 0x02 0x01 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 )
Undefined symbols for architecture x86_64:
{{ "_main", referenced from:}}
{{ implicit entry/start for main executable}}
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
clang: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation)

vs.

~ clang -arch arm64 -miphoneos-version-min=14.0 ./hello.c
clang: warning: using sysroot for 'MacOSX' but targeting 'iPhone' [-Wincompatible-sysroot]
[... more warnings because I don't pass correct SDKs]

Get a Mach-O 64-bit executable arm64

@swift-ci create

Okay, it's definitely the old-style triple being passed to clang (not to build script). Check out the difference here

clang -Wno-unknown-warning-option -Werror=unguarded-availability-new -arch arm64 -target arm64-apple-ios14.0 -fno-stack-protector -v -c /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.c -o /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o

objdump --headers /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o | head -n 2

/Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o:    file format mach-o arm64

versus

clang -Wno-unknown-warning-option -Werror=unguarded-availability-new -arch arm64 -target arm64-apple-iphoneos14.0 -fno-stack-protector -v -c /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.c -o /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o 

objdump --headers /Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o | head -n 2

/Users/rwidmann/Downloads/cmark-iphoneos-arm64/CMakeFiles/3.19.3/CompilerIdC/CMakeCCompilerId.o:    file format elf64-littleaarch64

Please ensure you have this patch applied to your checkout f9be289b9e04b3d7650a6c093e624ff321cf399b, then remove your build directory and rerun the build.

Comment by Jonathan Hemi (JIRA)

Just saw the patch. Indeed this solves the issue.

Thanks so much!