#!/bin/sh
#
# V3 self-hosting fixpoint, driven by M2make.
#
#   Stage 1: build V3 with GNU Modula-2 (host FileIO)   -> $TMP/m2s1
#   Stage 2: m2s1 compiles the compiler (self-hosted FileIO)
#                                                       -> $TMP/stage2.ssa, $TMP/m2s2
#   Stage 3: m2s2 compiles the compiler (self-hosted FileIO)
#                                                       -> $TMP/stage3.ssa
#   Success: stage2.ssa == stage3.ssa (byte-identical).
#
# Cross-stage FileIO selection (explicit):
#   - Stage 1 (gm2) uses the **host** FileIO: compiler/src/FileIO.def/.mod
#     (GNU-Modula-2 specific; see compiler/build.sh).
#   - Stages 2+ (V3) use the **self-hosted** FileIO:
#     runtime/syslib/FileIO.def/.mod. To make M2make pick it, the V3
#     source tree is staged WITHOUT compiler/src/FileIO*, and
#     runtime/syslib is on the -I search path.
#
# Stage 1 uses `-m` (gm2's link pass rejects FORWARD); V3-facing sources
# are regenerated WITHOUT `-m` (real FORWARD declarations).
#
# Usage: bootstrap/fixpoint.sh   (from anywhere)
set -e

ROOT=$(cd "$(dirname "$0")/.." && pwd)
CC_DIR="$ROOT/compiler"
CR="${CR:-$HOME/Projets/Projets-Modula2/MyWork/CocoGm2/CR}"
M2MAKE="${M2MAKE:-$ROOT/tools/m2make/b_v3/M2make}"
TMP="${TMP:-/tmp/opencode}"
V3SRC="$TMP/v3src"
mkdir -p "$TMP"

if [ ! -x "$M2MAKE" ]; then
  echo "=== building M2make (b_v3) ==="
  (cd "$ROOT/tools/m2make" && ./build_m2.sh)
fi

echo "=== Stage 1: gm2 build (host FileIO, CR -m) ==="
cd "$CC_DIR"
./build.sh
cp M2 "$TMP/m2s1"

echo "=== preparing V3 sources (CR without -m; self-hosted FileIO) ==="
cd "$CC_DIR/src"
CRFRAMES="$(pwd)" "$CR" -C M2.atg >/dev/null
# Stage the compiler sources WITHOUT the host FileIO so that M2make
# resolves FileIO from runtime/syslib (the self-hosted one).
rm -rf "$V3SRC"; mkdir -p "$V3SRC"
for f in "$CC_DIR"/src/*.def "$CC_DIR"/src/*.mod; do
  case "$f" in
    */FileIO.def|*/FileIO.mod) ;;   # host FileIO: stage-1 only
    *) cp "$f" "$V3SRC/" ;;
  esac
done

build_stage() {
  # $1 = --m2bin compiler, $2 = output .ssa, $3 = output binary
  echo "=== $(basename "$3") built by $1 ==="
  cd "$V3SRC"
  rm -f gen_ssa/M2.ssa
  "$M2MAKE" -c m2 --m2bin "$1" --shim "$ROOT/runtime/syslib/shim.c" \
      -I "$ROOT/runtime/syslib" -I "$ROOT/stdlib" -o "$3" M2.mod
  cp gen_ssa/M2.ssa "$2"
}

build_stage "$TMP/m2s1" "$TMP/stage2.ssa" "$TMP/m2s2"
build_stage "$TMP/m2s2" "$TMP/stage3.ssa" "$TMP/m2s3"

echo "=== compare ==="
if cmp -s "$TMP/stage2.ssa" "$TMP/stage3.ssa"; then
  echo "FIXPOINT OK: stage2.ssa == stage3.ssa ($(wc -c < "$TMP/stage2.ssa") bytes)"
else
  echo "FIXPOINT FAILED:"; cmp "$TMP/stage2.ssa" "$TMP/stage3.ssa" || true
  exit 1
fi