#!/usr/bin/env bash
# Step 7: the integration hazard nobody asks about until the link fails.
#
# Today runtime/flan_rt.c, runtime/flan_dev.c and vendor/agent/flan_agent.c are
# compiled into the *program*, and lib/dynload_stubs.c into the *compiler*.
# Merging the processes puts all four and the OCaml runtime in one link. This
# checks, symbol by symbol, whether anything collides.
set -u
here=$(cd "$(dirname "$0")" && pwd)
root=$(cd "$here/../.." && pwd)
out=$(mktemp -d)
trap 'rm -rf "$out"' EXIT
cd "$root" || exit 1

defs() { nm --defined-only "$@" 2>/dev/null | awk 'NF==3 {print $3}' | sort -u; }

clang -c runtime/flan_rt.c            -o "$out/rt.o"    || exit 1
clang -c runtime/flan_dev.c           -o "$out/dev.o"   || exit 1
clang -c vendor/agent/flan_agent.c    -o "$out/ag.o"    || exit 1
clang -c -I"$(ocamlopt -where)" "$here/dynload_stubs.c" -o "$out/dl.o" || exit 1

defs "$out/rt.o" "$out/dev.o" "$out/ag.o" "$out/dl.o" > "$out/flan.syms"
defs /home/joe/.opam/default/lib/ocaml/libasmrun.a > "$out/ml.syms" 2>/dev/null
[ -s "$out/ml.syms" ] || defs "$(ocamlopt -where)/libasmrun.a" > "$out/ml.syms"

echo "Flan's own C defines $(wc -l < "$out/flan.syms") symbols;" \
     "libasmrun defines $(wc -l < "$out/ml.syms")."
echo "collisions between Flan's C and the OCaml runtime:"
if comm -12 "$out/flan.syms" "$out/ml.syms" | grep . ; then
  echo "  ^^ those would have to be renamed"
else
  echo "  none"
fi

echo "collisions among Flan's own four .c files:"
for a in rt dev ag dl; do defs "$out/$a.o" > "$out/$a.syms"; done
found=0
for a in rt dev ag dl; do
  for b in rt dev ag dl; do
    [ "$a" \< "$b" ] || continue
    c=$(comm -12 "$out/$a.syms" "$out/$b.syms")
    [ -n "$c" ] && { echo "  $a vs $b:"; echo "$c" | sed 's/^/    /'; found=1; }
  done
done
[ $found -eq 0 ] && echo "  none"

echo "what Flan's C needs that the OCaml runtime also exports (shared libc etc):"
nm --undefined-only "$out/rt.o" "$out/ag.o" 2>/dev/null | awk 'NF==2{print $2}' \
  | sort -u > "$out/need.syms"
comm -12 "$out/need.syms" "$out/ml.syms" | sed 's/^/  /' | head -20