#!/bin/sh
#
# V3 self-hosting fixpoint.
#
#   Stage 1: build V3 with GNU Modula-2 (CR -m, gm2)   -> $TMP/m2s1
#   Stage 2: $TMP/m2s1 compiles the whole compiler     -> $TMP/stage2.ssa
#            (and that image is assembled into $TMP/m2s2)
#   Stage 3: $TMP/m2s2 compiles the whole compiler     -> $TMP/stage3.ssa
#
# Success = Stage2.ssa and Stage3.ssa are byte-identical (the compiler
# reproduces its own image exactly). Stage 1's image equals Stage 2's
# too, but the meaningful check is between V3 stages.
#
# Notes: CR must be run WITHOUT -m for V3-facing sources (real FORWARD
# declarations); gm2's link pass rejects FORWARD, so Stage 1 uses -m.
# Stage 1 uses the host FileIO; the compiled image embeds the
# self-hosted runtime/syslib/FileIO from the session.
#
# 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}"
QBE="${QBE:-qbe}"
CC="${CC:-cc}"
TMP="${TMP:-/tmp/opencode}"
mkdir -p "$TMP"

SYS="../stdlib/storage.def ../stdlib/storage.mod \
     ../runtime/syslib/SysShim.def ../runtime/syslib/SysShim.mod \
     ../runtime/syslib/FileIO.def ../runtime/syslib/FileIO.mod \
     ../stdlib/strings.def ../stdlib/strings.mod"
SRC="src/SymTab.def src/SymTab.mod \
     src/QbeGen.def src/QbeGen.mod \
     src/M2S.def src/M2S.mod src/M2P.def src/M2P.mod src/M2.mod"

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

echo "=== V3-facing sources (CR without -m) ==="
cd "$CC_DIR/src"
CRFRAMES="$(pwd)" "$CR" -C M2.atg >/dev/null

stage() {
  # $1 = compiler binary, $2 = output .ssa path, $3 = output binary (or "")
  cd "$CC_DIR"
  rm -f gen_ssa/M2.ssa
  $1 $SYS $SRC >/dev/null
  [ -f gen_ssa/M2.ssa ] || { echo "no gen_ssa/M2.ssa from $1"; exit 1; }
  cp gen_ssa/M2.ssa "$2"
  if [ -n "$3" ]; then
    "$QBE" -o "$TMP/m2.s" gen_ssa/M2.ssa
    "$CC" -w "$TMP/m2.s" "$ROOT/runtime/syslib/shim.c" -o "$3" -lm
  fi
}

echo "=== Stage 2: V3 (gm2-built) compiles the compiler ==="
stage "$TMP/m2s1" "$TMP/stage2.ssa" "$TMP/m2s2"

echo "=== Stage 3: V3 (self-built) compiles the compiler ==="
stage "$TMP/m2s2" "$TMP/stage3.ssa" ""

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