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run.sh: force MacOs to run the executable natively when on Apple Silicon #79

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run.sh: force MacOs to run the executable natively when on Apple Silicon #79

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run.sh: force MacOs to run the executable natively when on Apple Silicon
nskobelevs Sep 23, 2025
d4b21af
Fix non-quoted `DYLD_INSERT_LIBRARIES` expansion
nskobelevs Sep 24, 2025
eb008b9
Convert to using `exec arch`
nskobelevs Sep 24, 2025
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22 changes: 20 additions & 2 deletions assets/nix/run.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -123,7 +123,7 @@ abs_path() {
echo "$(cd "$(dirname "$1")" && pwd)/$(basename "$1")"
}

# Set executable path and the extension to use for the libdoorstop shared object
# Set executable path and the extension to use for the libdoorstop shared object as well as check whether we're running on Apple Silicon
os_type="$(uname -s)"
case ${os_type} in
Linux*)
Expand All @@ -148,6 +148,14 @@ case ${os_type} in
;;
esac
lib_extension="dylib"

# CPUs for Apple Silicon are in the format "Apple M.."
cpu_type="$(sysctl -n machdep.cpu.brand_string)"
case "${cpu_type}" in
Apple*)
is_apple_silicon=1
;;
esac
Comment on lines +152 to +158
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My understanding is that on Intel Macs this would be something like Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz.

I don't have an Intel Mac to test this but I've reached out to a mate with one to check the output as a sanity check

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Maybe uname -m would work? Is there a world where this matches on Linux?

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@nskobelevs nskobelevs Sep 24, 2025 •
edited
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The uname shipped with MacOS is also a universal binary so it falls into the same pitfalls where it'll just run it via Rosetta and return x86_64.

Could run it via arch and ARCHPREFERENCES like the main executable but I'm not actually sure if the arch command shipped on Intel Macs behaves the same without throwing a fit. Will have someone who has an Intel Mac check this.

Is there a world where this matches on Linux?

My understanding is that machdep is an Apple only namespace, plus this is in the *Darwin*) branch so linux wouldn't reach here.

;;
*)
# alright whos running games on freebsd
Expand Down Expand Up @@ -309,4 +317,14 @@ else
export DYLD_INSERT_LIBRARIES="${doorstop_name}:${DYLD_INSERT_LIBRARIES}"
fi

exec "$executable_path" "$@"
if [ -n "${is_apple_silicon}" ]; then
export ARCHPREFERENCE="arm64,x86_64"
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From man arch:

ENVIRONMENT
     The environment variable ARCHPREFERENCE can be used to provide architecture order preferences.  It is checked before looking for the
     corresponding property list file.

...

ARCHPREFERENCE Values
  i386,x86_64,x86_64h,arm64,arm64e
    A specifier that matches any name.

This tells arch to prefer arm64 and only fallback to x86_64 if arm64 is not suitable for this executable.
This works as expected regardless of whether the executable is universal, arm64 or solely x86_64.


# We need to use arch for Apple Silicon to allow the executable to be run natively as otherwise if
# the executable is universal, supporting both x86_64 and arm64, MacOs will still run it as x86_64
# if the parent process is running as x86.
# arch also strips the DYLD_INSERT_LIBRARIES env var so we have to pass that in manually
exec arch -e DYLD_INSERT_LIBRARIES="${DYLD_INSERT_LIBRARIES}" "$executable_path" "$@"
else
exec "$executable_path" "$@"
fi
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