build-engine.sh

#!/usr/bin/env bash

set -euo pipefail
set -x

working_dir="$(pwd)"
script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"

mode="${1:-release}"
weval=""
if [[ $# > 1 ]] && [[ "$2" == "weval" ]]; then
    weval=-weval
fi
mozconfig="${working_dir}/mozconfig-${mode}${weval}"
objdir="obj-$mode${weval}"
outdir="$mode${weval}"
rebuild="${REBUILD_ENGINE:-0}"

cat << EOF > "$mozconfig"
ac_add_options --enable-project=js
ac_add_options --enable-application=js
ac_add_options --target=wasm32-unknown-wasi
ac_add_options --without-system-zlib
ac_add_options --without-intl-api
ac_add_options --disable-jit
ac_add_options --disable-shared-js
ac_add_options --disable-shared-memory
ac_add_options --disable-tests
ac_add_options --disable-clang-plugin
ac_add_options --enable-jitspew
ac_add_options --enable-optimize=-O3
ac_add_options --enable-js-streams
ac_add_options --enable-portable-baseline-interp
ac_add_options --prefix=${working_dir}/${objdir}/dist
mk_add_options MOZ_OBJDIR=${working_dir}/${objdir}
mk_add_options AUTOCLOBBER=1
EOF

target="$(uname)"
case "$target" in
  Linux)
    echo "ac_add_options --disable-stdcxx-compat" >> "$mozconfig"
    ;;

  Darwin)
    echo "ac_add_options --host=aarch64-apple-darwin" >> "$mozconfig"
    ;;

  *)
    echo "Unsupported build target: $target"
    exit 1
    ;;
esac

case "$mode" in
  release)
    echo "ac_add_options --disable-debug" >> "$mozconfig"
    ;;

  debug)
    echo "ac_add_options --enable-debug" >> "$mozconfig"
    ;;

  *)
    echo "Unknown build type: $mode"
    exit 1
    ;;
esac

case "$weval" in
  -weval)
    echo "ac_add_options --enable-portable-baseline-interp-force" >> "$mozconfig"
    echo "ac_add_options --enable-aot-ics" >> "$mozconfig"
    echo "ac_add_options --enable-aot-ics-force" >> "$mozconfig"
    echo "ac_add_options --enable-pbl-weval" >> "$mozconfig"
    ;;
esac

# For a full build (not a rebuild), we need to clone the repo and do some setup work.
# `rebuild.sh` invokes this script with REBUILD_ENGINE=1 which sets rebuild=1
# and skips this setup.
if [[ $rebuild == 0 ]]; then
    # Ensure the Rust version matches that used by Gecko, and can compile to WASI
    rustup target add wasm32-wasi

    fetch_commits=
    if [[ ! -a gecko-dev ]]; then

      # Clone Gecko repository at the required revision
      mkdir gecko-dev

      git -C gecko-dev init
      git -C gecko-dev remote add --no-tags -t wasi-embedding \
        origin "$(cat "$script_dir/gecko-repository")"

      fetch_commits=1
    fi

    target_rev="$(cat "$script_dir/gecko-revision")"
    if [[ -n "$fetch_commits" ]] || \
      [[ "$(git -C gecko-dev rev-parse HEAD)" != "$target_rev" ]]; then
      git -C gecko-dev fetch --depth 1 origin "$target_rev"
      git -C gecko-dev checkout FETCH_HEAD
    fi

    # Use Gecko's build system bootstrapping to ensure all dependencies are
    # installed
    cd gecko-dev
    ./mach --no-interactive bootstrap --application-choice=js --no-system-changes

    # ... except, that doesn't install the wasi-sysroot, which we need, so we do
    # that manually.
    cd ~/.mozbuild
    python3 \
      "${working_dir}/gecko-dev/mach" \
      --no-interactive \
      artifact \
      toolchain \
      --bootstrap \
      --from-build \
      sysroot-wasm32-wasi
fi

cd "$working_dir"

# Build SpiderMonkey for WASI
MOZCONFIG="${mozconfig}" \
MOZ_FETCHES_DIR=~/.mozbuild \
CC=~/.mozbuild/clang/bin/clang \
CXX=~/.mozbuild/clang/bin/clang++ \
AR=~/.mozbuild/clang/bin/llvm-ar \
  python3 "${working_dir}/gecko-dev/mach" \
  --no-interactive \
    build

# Copy header, object, and static lib files
rm -rf "$outdir"
mkdir -p "$outdir/lib"

cd "$objdir"
cp -Lr dist/include "../$outdir"

while read -r file; do
  cp "$file" "../$outdir/lib"
done < "$script_dir/object-files.list"

cp js/src/build/libjs_static.a "wasm32-wasi/${mode}/libjsrust.a" "../$outdir/lib"