`check-libc` fails to compile on macOS

[duncpro]

Versions

• macOS 15.0.1 MacBook Pro M1
• tested on llvm-project libc at 0be1883
• system llvm version: llvm: stable 19.1.2

Steps to Reproduce

LLVM_BIN="$(brew --prefix llvm)/bin"

cd llvm-project
mkdir -p build
cd build

cmake ../runtimes \
    -G Ninja \
    -DCMAKE_CXX_FLAGS="-I$(xcrun --show-sdk-path)/usr/include -Wno-nullability-completeness" \
    -DCMAKE_C_FLAGS="-I$(xcrun --show-sdk-path)/usr/include -Wno-nullability-completeness" \
    -DLLVM_ENABLE_RUNTIMES="libc;compiler-rt" \
    -DLLVM_LIBC_FULL_BUILD=ON \
    -DCMAKE_BUILD_TYPE=Release \
    -DLLVM_LIBC_INCLUDE_SCUDO=ON \
    -DCOMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC=ON \
    -DCOMPILER_RT_BUILD_GWP_ASAN=OFF\
    -DCOMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED=OFF \
    -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
    -DLLVM_ENABLE_SPHINX=OFF -DLIBC_INCLUDE_DOCS=OFF \
    -DLIBC_CMAKE_VERBOSE_LOGGING=ON \
    -DCMAKE_C_COMPILER=$LLVM_BIN/clang \
    -DCMAKE_CXX_COMPILER=$LLVM_BIN/clang++ \
# Build files have been written to: /Users/duncanproctor/llvm-project/build

ninja libc 
# [125/125] Linking CXX static library libc/lib/libc.a

ninja check-libc
# ...
# 15 errors generated.
# [53/1548] Building CXX object libc/test/UnitTest/CMakeFiles/LibcTest.unit.dir/LibcTest.cpp.o
# ninja: build stopped: subcommand failed.

Full Error

In file included from /Users/duncanproctor/llvm-project/libc/src/fenv/feraiseexcept.cpp:10:
In file included from /Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/FEnvImpl.h:22:
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:37:7: error: static assertion failed due to requirement 'sizeof(fenv_t) == sizeof(__llvm_libc_20_0_0_git::fputil::FEnv::FPState)': Internal floating point state does not match the public fenv_t type.
   37 |       sizeof(fenv_t) == sizeof(FPState),
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:37:22: note: expression evaluates to '8 == 16'
   37 |       sizeof(fenv_t) == sizeof(FPState),
      |       ~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:72:23: error: use of undeclared identifier 'FE_FLUSHTOZERO'; did you mean 'EX_FLUSHTOZERO'?
   72 |            ((status & FE_FLUSHTOZERO) ? EX_FLUSHTOZERO : 0);
      |                       ^~~~~~~~~~~~~~
      |                       EX_FLUSHTOZERO
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:56:29: note: 'EX_FLUSHTOZERO' declared here
   56 |   static constexpr uint32_t EX_FLUSHTOZERO = 0x20;
      |                             ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:76:24: error: use of undeclared identifier '__fpcr_trap_invalid'
   76 |     return ((control & __fpcr_trap_invalid) ? EX_INVALID : 0) |
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:77:24: error: use of undeclared identifier '__fpcr_trap_divbyzero'
   77 |            ((control & __fpcr_trap_divbyzero) ? EX_DIVBYZERO : 0) |
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:78:24: error: use of undeclared identifier '__fpcr_trap_overflow'
   78 |            ((control & __fpcr_trap_overflow) ? EX_OVERFLOW : 0) |
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:79:24: error: use of undeclared identifier '__fpcr_trap_underflow'
   79 |            ((control & __fpcr_trap_underflow) ? EX_UNDERFLOW : 0) |
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:80:24: error: use of undeclared identifier '__fpcr_trap_inexact'
   80 |            ((control & __fpcr_trap_inexact) ? EX_INEXACT : 0) |
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:81:24: error: use of undeclared identifier '__fpcr_flush_to_zero'
   81 |            ((control & __fpcr_flush_to_zero) ? EX_FLUSHTOZERO : 0);
      |                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:90:42: error: use of undeclared identifier 'FE_FLUSHTOZERO'; did you mean 'EX_FLUSHTOZERO'?
   90 |            ((excepts & EX_FLUSHTOZERO) ? FE_FLUSHTOZERO : 0);
      |                                          ^~~~~~~~~~~~~~
      |                                          EX_FLUSHTOZERO
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:56:29: note: 'EX_FLUSHTOZERO' declared here
   56 |   static constexpr uint32_t EX_FLUSHTOZERO = 0x20;
      |                             ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:94:38: error: use of undeclared identifier '__fpcr_trap_invalid'
   94 |     return ((excepts & EX_INVALID) ? __fpcr_trap_invalid : 0) |
      |                                      ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:95:40: error: use of undeclared identifier '__fpcr_trap_divbyzero'
   95 |            ((excepts & EX_DIVBYZERO) ? __fpcr_trap_divbyzero : 0) |
      |                                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:96:39: error: use of undeclared identifier '__fpcr_trap_overflow'
   96 |            ((excepts & EX_OVERFLOW) ? __fpcr_trap_overflow : 0) |
      |                                       ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:97:40: error: use of undeclared identifier '__fpcr_trap_underflow'
   97 |            ((excepts & EX_UNDERFLOW) ? __fpcr_trap_underflow : 0) |
      |                                        ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:98:38: error: use of undeclared identifier '__fpcr_trap_inexact'
   98 |            ((excepts & EX_INEXACT) ? __fpcr_trap_inexact : 0) |
      |                                      ^
/Users/duncanproctor/llvm-project/libc/src/__support/FPUtil/aarch64/fenv_darwin_impl.h:99:42: error: use of undeclared identifier '__fpcr_flush_to_zero'
   99 |            ((excepts & EX_FLUSHTOZERO) ? __fpcr_flush_to_zero : 0);

[lntue]

This is full build mode (-DLLVM_LIBC_FULL_BUILD=ON) on macOS which doesn't work at the moment (mostly because we don't have syscall support for macOS yet). Overlay mode for macOS should work fine now.

[duncpro]

Thank you! I will try the overlay mode now.

FYI: I was originally following this guide: https://libc.llvm.org/full_cross_build.html. Perhaps a supported platforms table should be added?

Edit: Got it to compile using Apple Clang (not LLVM Clang) and overlay mode.

[lntue]

Thank you! I will try the overlay mode now.

FYI: I was originally following this guide: https://libc.llvm.org/full_cross_build.html. Perhaps a supported platforms table should be added?

Edit: Got it to compile using Apple Clang (not LLVM Clang) and overlay mode.

Yes, our documentations are due for updates now, especially those build recipes.

[duncpro]

What is the most well-supported platform right now? I'd like to be able to build and run all the existing tests, with all the features enabled. Is there a certain version of Linux you guys are focusing on right now, or a version which you know builds and tests correctly?

[michaelrj-google]

Most of the development is done on x64 debian, but other linux distros should work fine. If you're looking to set something up then ubuntu should also work and might be easier to work with. Just make sure you've got a recent version of clang (you can compile it from the LLVM sources if it's not available from your package manager).