#!/bin/bash
# clang in the CLT's usr/bin: the Darwin cross compiler xnu's makefiles get
# from `xcrun -find clang` (and through it LD = $(KC++) and MIGCC := $(CC)).
# It runs $CROSS_CLANG, the clang setup-toolchain.py builds with
# llvm-xnu-builtin-type.patch, with what Apple's clang does by itself for this
# target:
#
#   -target $DARWIN_TRIPLE  -arch alone does not switch clang off the Linux
#                       host triple, and xnu never passes -target for MacOSX
#                       (MakeInc.def uses -mmacosx-version-min).
#   $CROSS_EXTRA_FLAGS  -fptrauth-function-pointer-type-discrimination (on for
#                       -mkernel in Apple clang, opt-in upstream);
#                       -mllvm -disable-atexit-based-global-dtor-lowering, so C++
#                       static destructors land in __mod_term_func as the
#                       kernel expects; the __ARM_ARCH_8_2__..8_5__ Apple clang
#                       predefines for -mcpu=apple-a14.
#   $XNU_CLANG_DROP_FLAGS  removed: -mno-implicit-sme, Apple-only, which
#                       MakeInc.def passes; upstream never emits SME implicitly
#                       here, so dropping it is a no-op.
#
# The build driver (scripts/unixnu/kernel.py) sets CROSS_CLANG, DARWIN_TRIPLE
# and CROSS_EXTRA_FLAGS for UniXNU's plain arm64 iOS 17 kernel; the defaults are
# an arm64e macOS 26 target.
real="${CROSS_CLANG:-/opt/unixnu-linux/llvm/bin/clang}"
drop=(${XNU_CLANG_DROP_FLAGS--mno-implicit-sme})
args=()
for a in "$@"; do
    skip=0
    for d in "${drop[@]}"; do [ "$a" = "$d" ] && skip=1 && break; done
    [ "$skip" = 1 ] || args+=("$a")
done
exec "${real}" -target "${DARWIN_TRIPLE:-arm64e-apple-macos26.0}" \
    ${CROSS_EXTRA_FLAGS--fptrauth-function-pointer-type-discrimination -mllvm -disable-atexit-based-global-dtor-lowering -D__ARM_ARCH_8_2__=1 -D__ARM_ARCH_8_3__=1 -D__ARM_ARCH_8_4__=1 -D__ARM_ARCH_8_5__=1} \
    "${args[@]}"