V8 gets incorrect compiler and/or arguments when cross compiling macOS x86_64 -> arm64

[djmarcin]

Version

16.10.0 source

Platform

Darwin mbp.local 20.6.0 Darwin Kernel Version 20.6.0: Mon Aug 30 06:12:21 PDT 2021; root:xnu-7195.141.6~3/RELEASE_X86_64 x86_64

Subsystem

v8

What steps will reproduce the bug?

check out 16.10.0 sources

CC_host="ccache clang" CXX_host="ccache clang++" \
  CC_target="ccache clang -arch arm64" CXX_target="ccache clang++ -arch arm64" \
  CC="ccache clang -arch arm64" CXX="ccache clang++ -arch arm64" \
  ./configure --dest-cpu=arm64
mkdir -p /tmp/node-install
make -j$(nproc) install V=0 DESTDIR=/tmp/node-install

Eventually:

../deps/v8/src/trap-handler/handler-inside-posix.cc:108:47: error: no member named '__pc' in '__darwin_x86_thread_state64'
    auto* context_ip = &uc->uc_mcontext->__ss.__pc;
                        ~~~~~~~~~~~~~~~~~~~~~ ^
1 error generated.

The command line for this compilation stage appears to be:

$CC_host ... '-DV8_TARGET_ARCH_ARM64' ...

Since $CC_host (x86_64) and the define (arm64) are mismatched, compilation produces the above error.

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior?

The compiler and define should be matched properly and the compile should succeed.

What do you see instead?

compilation fails

Additional information

Offshoot of comment in #40302

[djmarcin]

I think the problem is that v8_base_without_compiler is built for obj.host when cross compiling, but features.gypi sets v8_target_arch without regard for whether the target being built is in the #host or #target toolset. It's not clear to me from the documentation how you condition based on this.

[mscdex]

Aren't you missing at least --cross-compiling in your ./configure command line ?

[djmarcin]

As far as I can tell, --cross-compiling is optional and inferred by target_arch != host_arch when it is not set. The same error occurs even with passing --cross-compiling specifically.

The generated file out/tools/v8_gypfiles/v8_base_without_compiler.host.mk shows that the argument '-DV8_TARGET_ARCH_ARM64' is generated, but it should be building for the host configuration which should be '-DV8_TARGET_ARCH_X64'.

[targos]

Any chance #40488 fixes it (more specifically this commit: 6168301)?

[RaisinTen]

I can confirm that 6ac1ccc fixes this issue. Sent #43247 to backport it to v16.x-staging.

[RaisinTen]

The backported fix has landed in v16.15.1, closing.