# Ubuntu 24.04 is used here (rather than AlmaLinux 8) because it has
# riscv64 cross-compilation packages in its repositories.
FROM ubuntu:24.04

RUN apt-get update && apt-get install -y --no-install-recommends \
  curl \
  ca-certificates \
  crossbuild-essential-riscv64 \
  clang \
  lld \
  python3 \
  git \
  unzip \
  cmake \
  ninja-build \
  ccache \
  && rm -rf /var/lib/apt/lists/*

# Cargo needs an explicit linker when cross-compiling for riscv64.
# The C/C++ cross-compiler is passed via CMAKE_C/CXX_COMPILER cmake flags
# rather than CC/CXX env vars so that LLVM's native tblgen sub-build can
# still find the host compiler (cmake cache vars are not inherited by
# subprocess cmake invocations, but env vars are).
ENV CARGO_TARGET_RISCV64GC_UNKNOWN_LINUX_GNU_LINKER=riscv64-linux-gnu-gcc

# Tell programs to cache in a location that both isn't a `--volume` mounted root
# and isn't `/root` in the container as that won't be writable during the build.
ENV XDG_CACHE_HOME=/tmp/cache