FROM scratch as base
ENV GCC_VERSION 13.1.0
ENV GCC_HASH 61d684f0aa5e76ac6585ad8898a2427aade8979ed5e7f85492286c4dfc13ee86
ENV GCC_FILE gcc-$GCC_VERSION.tar.xz
ENV GCC_SITE https://mirrors.kernel.org/gnu/gcc/gcc-${GCC_VERSION}/${GCC_FILE}
ENV GMP_VERSION 6.2.1
ENV GMP_HASH eae9326beb4158c386e39a356818031bd28f3124cf915f8c5b1dc4c7a36b4d7c
ENV GMP_FILE gmp-${GMP_VERSION}.tar.bz2
ENV GMP_SITE https://gcc.gnu.org/pub/gcc/infrastructure/${GMP_FILE}
ENV MPFR_VERSION 4.1.0
ENV MPFR_HASH feced2d430dd5a97805fa289fed3fc8ff2b094c02d05287fd6133e7f1f0ec926
ENV MPFR_FILE mpfr-${MPFR_VERSION}.tar.bz2
ENV MPFR_SITE https://gcc.gnu.org/pub/gcc/infrastructure/${MPFR_FILE}
ENV MPC_VERSION 1.2.1
ENV MPC_HASH 17503d2c395dfcf106b622dc142683c1199431d095367c6aacba6eec30340459
ENV MPC_FILE mpc-${MPC_VERSION}.tar.gz
ENV MPC_SITE https://gcc.gnu.org/pub/gcc/infrastructure/${MPC_FILE}
ENV ISL_VERSION 0.24
ENV ISL_HASH fcf78dd9656c10eb8cf9fbd5f59a0b6b01386205fe1934b3b287a0a1898145c0
ENV ISL_FILE isl-${ISL_VERSION}.tar.bz2
ENV ISL_SITE https://gcc.gnu.org/pub/gcc/infrastructure/${ISL_FILE}
ENV MUSL_VERSION 1.2.4
ENV MUSL_FILE musl-${MUSL_VERSION}.tar.gz
ENV MUSL_SITE http://musl.libc.org/releases/${MUSL_FILE}
ENV MUSL_HASH 7a35eae33d5372a7c0da1188de798726f68825513b7ae3ebe97aaaa52114f039
ENV LINUX_VERSION 6.6
ENV LINUX_HASH d926a06c63dd8ac7df3f86ee1ffc2ce2a3b81a2d168484e76b5b389aba8e56d0
ENV LINUX_FILE linux-${LINUX_VERSION}.tar.xz
ENV LINUX_SITE https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/${LINUX_FILE}
ENV BINUTILS_VERSION 2.35
ENV BINUTILS_HASH 1b11659fb49e20e18db460d44485f09442c8c56d5df165de9461eb09c8302f85
ENV BINUTILS_FILE binutils-${BINUTILS_VERSION}.tar.xz
ENV BINUTILS_SITE https://ftp.gnu.org/gnu/binutils/${BINUTILS_FILE}
ENV TARGET_ARCH=x86_64
ENV HOST_ARCH=i386
ENV BUILD=${HOST_ARCH}-unknown-linux-musl
ENV HOST=${HOST_ARCH}-unknown-linux-musl
ENV TARGET=${TARGET_ARCH}-linux-musl
ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
ENV USER=user
ENV HOME=/home/${USER}
ENV TZ=UTC
ENV LANG=C.UTF-8
ENV SOURCE_DATE_EPOCH=1
ENV KCONFIG_NOTIMESTAMP=1
ENV SYSROOT_DIR ${HOME}/build-sysroot
ENV GCC_DIR ${HOME}/build-gcc
ENV LINUX_DIR ${HOME}/build-linux
ENV BINUTILS_DIR ${HOME}/build-binutils
ENV MUSL_DIR=${HOME}/build-musl

FROM base as fetch
WORKDIR ${HOME}
ADD --checksum=sha256:${LINUX_HASH} ${LINUX_SITE} .
ADD --checksum=sha256:${MUSL_HASH} ${MUSL_SITE} .
ADD --checksum=sha256:${BINUTILS_HASH} ${BINUTILS_SITE} .
ADD --checksum=sha256:${GCC_HASH} ${GCC_SITE} .
ADD --checksum=sha256:${GMP_HASH} ${GMP_SITE} .
ADD --checksum=sha256:${MPFR_HASH} ${MPFR_SITE} .
ADD --checksum=sha256:${MPC_HASH} ${MPC_SITE} .
ADD --checksum=sha256:${ISL_HASH} ${ISL_SITE} .

FROM fetch as build
COPY --from=stagex/stage1 . /
RUN --network=none <<-EOF
    set -eux
    tar -xf ${LINUX_FILE}
    tar -xzf ${MUSL_FILE}
    tar -xf ${BINUTILS_FILE}
    tar -xf ${GCC_FILE}
    cd gcc-${GCC_VERSION}
    mv ../*.tar.* .; \
    ./contrib/download_prerequisites
EOF

# Phase 1: Build cross binutils in build-binutils
WORKDIR ${BINUTILS_DIR}
RUN --network=none <<-EOF
    set -eux
    ../binutils-${BINUTILS_VERSION}/configure \
        --build=${BUILD} \
        --host=${HOST} \
        --target=${TARGET} \
        --with-sysroot=/${TARGET} \
        --prefix= \
        --libdir=/lib \
        --disable-nls \
        --disable-multilib \
        --disable-plugins \
        --disable-gprofng \
        --enable-64-bit-bfd \
        --enable-ld=default \
        --enable-install-libiberty \
        --enable-deterministic-archives
    make all
EOF

# Phase 2: Prepare build sysroot
WORKDIR ${SYSROOT_DIR}
RUN <<-EOF
    set -eux
    mkdir -p include
    ln -sf . usr
    ln -sf lib lib32
    ln -sf lib lib64
EOF

# Phase 3: Build gcc (without libgcc) in build-gcc
WORKDIR ${GCC_DIR}
RUN --network=none <<-EOF
    set -eux
    ../gcc-${GCC_VERSION}/configure \
        --build=${BUILD} \
        --host=${HOST} \
        --target=${TARGET} \
        --with-build-sysroot=${SYSROOT_DIR} \
        --with-sysroot=/${TARGET} \
        --prefix= \
        --libdir=/lib \
        --disable-multilib \
        --disable-bootstrap \
        --disable-assembly \
        --disable-libmudflap \
        --disable-libsanitizer \
        --disable-gnu-indirect-function \
        --disable-libmpx \
        --disable-werror \
        --enable-languages=c,c++ \
        --enable-tls \
        --enable-initfini-array \
        --enable-libstdcxx-time=rt \
        --enable-deterministic-archives \
        AR_FOR_TARGET=${BINUTILS_DIR}/binutils/ar \
        AS_FOR_TARGET=${BINUTILS_DIR}/gas/as-new \
        LD_FOR_TARGET=${BINUTILS_DIR}/ld/ld-new \
        NM_FOR_TARGET=${BINUTILS_DIR}/binutils/nm-new \
        OBJCOPY_FOR_TARGET=${BINUTILS_DIR}/binutils/objcopy \
        OBJDUMP_FOR_TARGET=${BINUTILS_DIR}/binutils/objdump \
        RANLIB_FOR_TARGET=${BINUTILS_DIR}/binutils/ranlib \
        READELF_FOR_TARGET=${BINUTILS_DIR}/binutils/readelf \
        STRIP_FOR_TARGET=${BINUTILS_DIR}/binutils/strip-new
    make all-gcc
EOF

# Phase 4: Install musl libc headers to build-sysroot for use by libgcc
WORKDIR ${MUSL_DIR}
RUN --network=none <<-EOF
    set -eux
    ../musl-${MUSL_VERSION}/configure \
        CC="${GCC_DIR}/gcc/xgcc -B ${GCC_DIR}/gcc" \
        LIBCC="${GCC_DIR}/${TARGET}/libgcc/libgcc.a" \
        --prefix= \
        --host=${TARGET}
    make DESTDIR=${SYSROOT_DIR} install-headers
EOF

# Phase 5: Compile libgcc
WORKDIR ${GCC_DIR}
RUN --network=none make MAKE="make enable_shared=no" all-target-libgcc

# Phase 5: Compile musl libc and install to sysroot
WORKDIR ${MUSL_DIR}
RUN --network=none <<-EOF
    set -eux
    make \
        AR=${BINUTILS_DIR}/binutils/ar \
        RANLIB=${BINUTILS_DIR}/binutils/ranlib
    make DESTDIR=${SYSROOT_DIR} install
EOF

# Phase 6: Compile remaining gcc targets
WORKDIR ${GCC_DIR}
RUN make all

# Phase 7: Generate linux headers
WORKDIR ${HOME}/linux-${LINUX_VERSION}
RUN --network=none <<-EOF
    set -eux
    make ARCH=${TARGET_ARCH} headers
    find usr/include -name '.*' -delete
    rm usr/include/Makefile
    rm usr/include/headers_check.pl
    cp -rv usr/include ${LINUX_DIR}
EOF

FROM build as install
WORKDIR ${HOME}
COPY --from=stagex/stage1 . /rootfs/
RUN <<-EOF
    set -eux
    rm /rootfs/lib
    env -C build-musl make DESTDIR=/rootfs/${TARGET} install
    env -C build-gcc make DESTDIR=/rootfs/ install
    env -C build-binutils make DESTDIR=/rootfs/ install
    cp -Rv ${LINUX_DIR}/* /rootfs/${TARGET}/include
    ln -s /usr/lib/ld-musl-${HOST_ARCH}.so.1 /rootfs/lib/libc.so
    ln -s /usr/lib/ld-musl-${HOST_ARCH}.so.1 /rootfs/lib/ld-musl-${HOST_ARCH}.so.1
    ln -s /${TARGET}/lib/ld-musl-${TARGET_ARCH}.so.1 /rootfs/lib/ld-musl-${TARGET_ARCH}.so.1
EOF

FROM base as package
COPY --from=install /rootfs/ /
USER 1000:1000
ENTRYPOINT ["/bin/bash"]
ENV PS1="stage2 $ "