#!/usr/bin/env bash
# brintOS LLVM build — the wasm32-hwjs toolchain (see BRINTOS.md).
#
# Builds clang + lld + opt + llvm-config + libLLVM at the brintOS pin with the
# dylib + plugin flags the hwjs-cc coroutine pass requires, plus the LLVM
# binutils the kernel and distro builds invoke (llvm-ar/nm/link/objcopy/strip/
# objdump/readelf/ranlib — Kbuild's LLVM=1 and the wasmld merge need them).
# Output lands in ./build/bin, which hwjs-cc/toolchain/find-llvm.sh discovers
# automatically.
#
# Usage:
#   ./build-brintos.sh            # configure + build (uses all cores)
#   ./build-brintos.sh -j 8       # cap parallelism
#   BUILD_DIR=/tmp/llvm ./build-brintos.sh
set -euo pipefail

HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
BUILD_DIR="${BUILD_DIR:-$HERE/build}"
JOBS=""
while [ $# -gt 0 ]; do
  case "$1" in
    -j) JOBS="$2"; shift ;;
    -j*) JOBS="${1#-j}" ;;
    -h|--help) sed -n '2,12p' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'; exit 0 ;;
    *) echo "build-brintos.sh: unknown argument '$1'" >&2; exit 2 ;;
  esac
  shift
done

for tool in cmake ninja; do
  command -v "$tool" >/dev/null 2>&1 || { echo "build-brintos.sh: FATAL: '$tool' not found on PATH." >&2; exit 1; }
done

echo "brintOS LLVM: configuring (build dir: $BUILD_DIR)"
cmake -G Ninja -S "$HERE/llvm" -B "$BUILD_DIR" \
  -DCMAKE_BUILD_TYPE=Release \
  -DLLVM_ENABLE_PROJECTS="clang;lld" \
  -DLLVM_TARGETS_TO_BUILD="X86;WebAssembly" \
  -DLLVM_ENABLE_ASSERTIONS=OFF \
  -DLLVM_BUILD_LLVM_DYLIB=ON \
  -DLLVM_LINK_LLVM_DYLIB=ON \
  -DLLVM_ENABLE_PLUGINS=ON \
  -DCLANG_PLUGIN_SUPPORT=ON \
  -DLLVM_INCLUDE_TESTS=OFF \
  -DLLVM_INCLUDE_BENCHMARKS=OFF \
  -DLLVM_INCLUDE_EXAMPLES=OFF \
  -DLLVM_OPTIMIZED_TABLEGEN=ON \
  -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++

# The binutils list is load-bearing: the wasm32 kernel build pins AR/NM/OBJCOPY
# to this build's bin (and Kbuild's LLVM=1 derives STRIP/OBJDUMP/READELF), and
# hwjs-cc's wasmld drives llvm-link. A default `ninja clang lld` build does NOT
# produce these, so a fresh clone's `make kernel` would die at the first
# OBJCOPY step (reported as ticket: "make kernel stops at modules.builtin.modinfo").
BINUTILS="llvm-ar llvm-nm llvm-ranlib llvm-link llvm-objcopy llvm-strip llvm-objdump llvm-readelf"
echo "brintOS LLVM: building clang lld opt llvm-config $BINUTILS (+ libLLVM dylib)"
# shellcheck disable=SC2086  # BINUTILS is a deliberate word-split target list
ninja -C "$BUILD_DIR" ${JOBS:+-j "$JOBS"} clang lld opt llvm-config $BINUTILS

# Loud verification: every tool downstream builds invoke must exist now, or
# the failure surfaces here instead of deep inside a kernel/distro build.
for t in clang wasm-ld opt llvm-config $BINUTILS; do
  [ -x "$BUILD_DIR/bin/$t" ] || { echo "build-brintos.sh: FATAL: '$t' missing from $BUILD_DIR/bin after build." >&2; exit 1; }
done

echo
echo "brintOS LLVM: done."
echo "  bin: $BUILD_DIR/bin"
"$BUILD_DIR/bin/clang" --version | head -1 || true
echo "hwjs-cc will discover this automatically; or point at it explicitly:"
echo "  export WASMLD_HWJS_LLVM_BIN=$BUILD_DIR/bin"