Dockerfile.clang

#syntax=docker/dockerfile:1.6

# Alpine still doesn't support riscv64 in a mainline, only on 'edge' branch
# As soon as it will be available in mainline, we can use it for 0 price
# for now one can just set ALPINE_VERSION to 'edge' for
# experements with riscv64. Clang is a cross compiler by default and no extra
# steps are required to build for riscv64

ARG ALPINE_VERSION=3.18
FROM --platform=${BUILDPLATFORM} alpine:${ALPINE_VERSION} as builder-base
RUN apk add --no-cache \
    build-base \
    clang \
    git \
    openssl-dev \
    linux-headers \
    musl-dev \
    libgcc \
    flex \
    bison \
    lld \
    llvm \
    elfutils-dev \
    bash \
    findutils \
    diffutils \
    pahole \
    perl \
    ccache \
    # for ZFS
    automake \
    autoconf \
    libtool \
    util-linux-dev \
    libtirpc-dev \
    libaio-dev \
    python3 \
    # for module signing
    openssl


ARG TARGETARCH
ARG BUILDARCH
ARG BUILDOS

FROM builder-base as builder-amd64
ARG KERNEL_DEFCONFIG=eve_defconfig
ARG ARCH=x86_64
ARG ZFS_CROSS_HOST=x86_64-linux-musl

FROM builder-base as builder-arm64
ARG KERNEL_DEFCONFIG=defconfig
ARG ARCH=arm64
ARG ZFS_CROSS_HOST=aarch64-linux-musl

FROM builder-base as builder-riscv64
ARG KERNEL_DEFCONFIG=eve_defconfig
ARG ARCH=riscv
ARG ZFS_CROSS_HOST=riscv64-linux-musl

FROM builder-${TARGETARCH} as builder

# TODO: add full support for dirty source tree
ENV KBUILD_BUILD_USER="eve"
ENV KBUILD_BUILD_HOST="eve"
ENV KCONFIG_NOTIMESTAMP="true"

# RUN --mount=type=bind,target=/kernel-src \
#     if [ $(git diff --quiet HEAD -- :"/kernel-src") ] || [ $(git ls-files --other --directory --exclude-standard :"/kernel-src" | grep .) ]; then \
#         KBUILD_BUILD_TIMESTAMP=$(LC_ALL=C date) \
#         SOURCE_DATE_EPOCH=$(date +%s) \
#         KBUILD_BUILD_USER=$(whoami | $SED 's/\\/\\\\/') \
#         KBUILD_BUILD_HOST=$(uname -n) \
#         KCONFIG_NOTIMESTAMP="false" \
#     else \
#         SOURCE_DATE_EPOCH=$(git log -1 --format=%ct "/kernel-src") \
#         KBUILD_BUILD_TIMESTAMP=$(git log -1 --format=%cd "/kernel-src" | cut -f1 -d"+") \
#     fi

# need to bind mount as readwrite so mrproper works on /kernel-src
RUN  --mount=type=bind,target=/kernel-src,readwrite \
     --mount=type=cache,target=/root/.cache/ccache \
     ccache -z && \
     # clean source tree, it should be done exactly this way (no make -C)
     cd /kernel-src && make ARCH=${ARCH} LLVM=1 -j$(nproc) mrproper && \
     # --mount=type=bind cannot mount to target=/ so we have to do out-of-tree build for kernel
     make -C /kernel-src O=/kernel-out CC="ccache clang" ARCH=${ARCH} LLVM=1 -j$(nproc) ${KERNEL_DEFCONFIG} && \
     make -C /kernel-src O=/kernel-out CC="ccache clang" ARCH=${ARCH} LLVM=1 -j$(nproc) prepare && \
     make -C /kernel-src O=/kernel-out CC="ccache clang" ARCH=${ARCH} LLVM=1 -j$(nproc) && \
     make -C /kernel-src O=/kernel-out CC="ccache clang" ARCH=${ARCH} LLVM=1 -j$(nproc) INSTALL_MOD_STRIP=1 \
     INSTALL_MOD_PATH=/tmp/kernel-modules modules_install && \
     ccache -s
FROM builder as zfs-config

# build ZFS module out-of-tree
ADD https://github.com/mikem-zed/zfs.git#eve-zfs-2.1.12 /tmp/zfs
WORKDIR /tmp/zfs
RUN --mount=type=bind,target=/kernel-src,readwrite \
    --mount=type=cache,target=/root/.cache/ccache \
    --mount=type=cache,target=/tmp/zfs/build \
    ./autogen.sh

RUN --mount=type=bind,target=/kernel-src,readwrite \
    --mount=type=cache,target=/root/.cache/ccache \
    --mount=type=cache,target=/tmp/zfs/build \
    CC="clang" LD="ld.lld" STRIP="llvm-strip" AR="llvm-ar" ./configure -v \
    --with-config=kernel \
    --with-linux=/kernel-src \
    --with-linux-obj=/kernel-out \
    # unfortunately $ARCH is not enough for ./configure to detect cross compiler
    --host=${ZFS_CROSS_HOST} \
    --build=${BUILDARCH}-${BUILDOS}-musl \
    KERNEL_LLVM=1 \
    # we cannot set "ccache clang" because autoconf scripts do not properly escape
    # spaces in CC variable. But it should be ok for ./configure
    KERNEL_CC="clang" \
    KERNEL_LD="ld.lld" && \
    ./scripts/make_gitrev.sh

FROM zfs-config as zfs-build

RUN --mount=type=bind,target=/kernel-src,readwrite \
    --mount=type=cache,target=/root/.cache/ccache \
    --mount=type=cache,target=/tmp/zfs/build \
    # here we can use ccache again
    make -C module CC="ccache clang" -j$(nproc) && \
    make -C module INSTALL_MOD_STRIP=1 INSTALL_MOD_PATH=/tmp/kernel-modules install && \
    ccache -s

# FROM scratch