#!/bin/sh
set -eu

: "${CPU_AS:?}" "${CPU_LD:?}" "${CPU_RUN:?}"

TMP=${TMPDIR:-/tmp}/libmcpu-symbol-scope-$$
mkdir -p "$TMP/lib"
trap 'rm -rf "$TMP"' EXIT HUP INT TERM

cat > "$TMP/main-import.s" <<'EOS'
.global _life
.extern foo
.text
_start_life:
        LDI     r64@0x00000, 40
        CALL    foo
        MOV     r64@0x00018, r64@0x00000
        LDI     r32@0x00030, 0
        EXIT    r32@0x00030
EOS

cat > "$TMP/a.s" <<'EOS'
.global foo
.text
foo:
        LDI     r64@0x00008, 2
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS

cat > "$TMP/b.s" <<'EOS'
.global foo
.text
foo:
        LDI     r64@0x00008, 3
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS

"$CPU_AS" -o "$TMP/main-import.o" "$TMP/main-import.s"
"$CPU_AS" -o "$TMP/a.o" "$TMP/a.s"
"$CPU_AS" -o "$TMP/b.o" "$TMP/b.s"
"$CPU_LD" --shared --soname=liba.so.1 -o "$TMP/lib/liba.so.1.0.0" "$TMP/a.o"
"$CPU_LD" --shared --soname=libb.so.1 -o "$TMP/lib/libb.so.1.0.0" "$TMP/b.o"
ln -s liba.so.1.0.0 "$TMP/lib/liba.so.1"
ln -s liba.so.1 "$TMP/lib/liba.so"
ln -s libb.so.1.0.0 "$TMP/lib/libb.so.1"
ln -s libb.so.1 "$TMP/lib/libb.so"

# Normal DT_NEEDED scope is breadth-first and left-to-right.  For equal
# GLOBAL definitions the first direct dependency wins.
"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -la -lb -o "$TMP/main-ab" "$TMP/main-import.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/main-ab"`" = 42 ]

"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -lb -la -o "$TMP/main-ba" "$TMP/main-import.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/main-ba"`" = 43 ]

# A main-executable GLOBAL outranks normal dependencies.
cat > "$TMP/main-own.s" <<'EOS'
.global _life
.global foo
.text
_start_life:
        LDI     r64@0x00000, 40
        CALL    foo
        MOV     r64@0x00018, r64@0x00000
        LDI     r32@0x00030, 0
        EXIT    r32@0x00030
foo:
        LDI     r64@0x00008, 1
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
"$CPU_AS" -o "$TMP/main-own.o" "$TMP/main-own.s"
"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -la -o "$TMP/main-own" "$TMP/main-own.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/main-own"`" = 41 ]

# Explicit preload is the intentional override scope.  Equal-strength GLOBAL
# preloads keep the historical rightmost-higher-priority rule.
[ "`"$CPU_RUN" --library-path="$TMP/lib" \
        --ldpreload=liba.so:libb.so \
        --int-reg=r64@0x00018 "$TMP/main-own"`" = 43 ]
[ "`"$CPU_RUN" --library-path="$TMP/lib" \
        --ldpreload=libb.so:liba.so \
        --int-reg=r64@0x00018 "$TMP/main-own"`" = 42 ]

# Binding strength outranks scope class: a WEAK preload must not preempt a
# normal GLOBAL definition.
cat > "$TMP/weak.s" <<'EOS'
.weak foo
.text
foo:
        LDI     r64@0x00008, 9
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
"$CPU_AS" -o "$TMP/weak.o" "$TMP/weak.s"
"$CPU_LD" --shared --soname=libweak.so.1 -o "$TMP/libweak.so" "$TMP/weak.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --ldpreload="$TMP/libweak.so" \
        --int-reg=r64@0x00018 "$TMP/main-ab"`" = 42 ]

# If only WEAK definitions exist, the same scope ordering applies: first normal
# dependency wins, while rightmost explicit preload wins.
cat > "$TMP/weak-main.s" <<'EOS'
.global _life
.weak foo
.text
_start_life:
        LDI     r64@0x00000, 40
        CALL    foo
        MOV     r64@0x00018, r64@0x00000
        LDI     r32@0x00030, 0
        EXIT    r32@0x00030
EOS
cat > "$TMP/wa.s" <<'EOS'
.weak foo
.text
foo:
        LDI     r64@0x00008, 2
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
cat > "$TMP/wb.s" <<'EOS'
.weak foo
.text
foo:
        LDI     r64@0x00008, 3
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
"$CPU_AS" -o "$TMP/weak-main.o" "$TMP/weak-main.s"
"$CPU_AS" -o "$TMP/wa.o" "$TMP/wa.s"
"$CPU_AS" -o "$TMP/wb.o" "$TMP/wb.s"
"$CPU_LD" --shared --soname=libwa.so.1 -o "$TMP/lib/libwa.so.1" "$TMP/wa.o"
"$CPU_LD" --shared --soname=libwb.so.1 -o "$TMP/lib/libwb.so.1" "$TMP/wb.o"
ln -s libwa.so.1 "$TMP/lib/libwa.so"
ln -s libwb.so.1 "$TMP/lib/libwb.so"
"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -lwa -lwb -o "$TMP/weak-main" "$TMP/weak-main.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/weak-main"`" = 42 ]
[ "`"$CPU_RUN" --ldpreload="$TMP/lib/libwa.so.1:$TMP/lib/libwb.so.1" \
        --int-reg=r64@0x00018 "$TMP/weak-main"`" = 43 ]

# A direct dependency outranks a conflicting transitive dependency.  The
# resolver must therefore build a true breadth-first scope rather than expose
# DFS traversal order to symbol resolution.
cat > "$TMP/deep.s" <<'EOS'
.global deep_anchor
.global foo
.text
deep_anchor:
        RET
foo:
        LDI     r64@0x00008, 9
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
cat > "$TMP/mid.s" <<'EOS'
.global mid_anchor
.extern deep_anchor
.text
mid_anchor:
        CALL    deep_anchor
        RET
EOS
cat > "$TMP/direct.s" <<'EOS'
.global foo
.text
foo:
        LDI     r64@0x00008, 3
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
cat > "$TMP/bfs-main.s" <<'EOS'
.global _life
.extern mid_anchor
.extern foo
.text
_start_life:
        LDI     r64@0x00000, 40
        CALL    mid_anchor
        CALL    foo
        MOV     r64@0x00018, r64@0x00000
        LDI     r32@0x00030, 0
        EXIT    r32@0x00030
EOS
"$CPU_AS" -o "$TMP/deep.o" "$TMP/deep.s"
"$CPU_AS" -o "$TMP/mid.o" "$TMP/mid.s"
"$CPU_AS" -o "$TMP/direct.o" "$TMP/direct.s"
"$CPU_AS" -o "$TMP/bfs-main.o" "$TMP/bfs-main.s"
"$CPU_LD" --shared --soname=libdeep.so.1 -o "$TMP/lib/libdeep.so.1.0.0" "$TMP/deep.o"
ln -s libdeep.so.1.0.0 "$TMP/lib/libdeep.so.1"
ln -s libdeep.so.1 "$TMP/lib/libdeep.so"
"$CPU_LD" --shared --soname=libmid.so.1 -L"$TMP/lib" -ldeep \
  -o "$TMP/lib/libmid.so.1.0.0" "$TMP/mid.o"
ln -s libmid.so.1.0.0 "$TMP/lib/libmid.so.1"
ln -s libmid.so.1 "$TMP/lib/libmid.so"
"$CPU_LD" --shared --soname=libdirect.so.1 -o "$TMP/lib/libdirect.so.1.0.0" "$TMP/direct.o"
ln -s libdirect.so.1.0.0 "$TMP/lib/libdirect.so.1"
ln -s libdirect.so.1 "$TMP/lib/libdirect.so"
"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -lmid -ldirect -o "$TMP/bfs-main" "$TMP/bfs-main.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/bfs-main"`" = 43 ]

# Diamond graph: A and B both depend on C.  SONAME deduplication loads C once,
# while the direct A/B scope still follows left-to-right order.
cat > "$TMP/common.s" <<'EOS'
.global common_anchor
.text
common_anchor:
        RET
EOS
cat > "$TMP/da.s" <<'EOS'
.global a_anchor
.global foo
.extern common_anchor
.text
a_anchor:
        CALL    common_anchor
        RET
foo:
        LDI     r64@0x00008, 2
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
cat > "$TMP/db.s" <<'EOS'
.global b_anchor
.global foo
.extern common_anchor
.text
b_anchor:
        CALL    common_anchor
        RET
foo:
        LDI     r64@0x00008, 3
        IADD    r64@0x00000, r64@0x00000, r64@0x00008
        RET
EOS
cat > "$TMP/diamond-main.s" <<'EOS'
.global _life
.extern a_anchor
.extern b_anchor
.extern foo
.text
_start_life:
        LDI     r64@0x00000, 40
        CALL    a_anchor
        CALL    b_anchor
        CALL    foo
        MOV     r64@0x00018, r64@0x00000
        LDI     r32@0x00030, 0
        EXIT    r32@0x00030
EOS
"$CPU_AS" -o "$TMP/common.o" "$TMP/common.s"
"$CPU_AS" -o "$TMP/da.o" "$TMP/da.s"
"$CPU_AS" -o "$TMP/db.o" "$TMP/db.s"
"$CPU_AS" -o "$TMP/diamond-main.o" "$TMP/diamond-main.s"
"$CPU_LD" --shared --soname=libcommon.so.1 -o "$TMP/lib/libcommon.so.1.0.0" "$TMP/common.o"
ln -s libcommon.so.1.0.0 "$TMP/lib/libcommon.so.1"
ln -s libcommon.so.1 "$TMP/lib/libcommon.so"
"$CPU_LD" --shared --soname=libda.so.1 -L"$TMP/lib" -lcommon \
  -o "$TMP/lib/libda.so.1.0.0" "$TMP/da.o"
ln -s libda.so.1.0.0 "$TMP/lib/libda.so.1"
ln -s libda.so.1 "$TMP/lib/libda.so"
"$CPU_LD" --shared --soname=libdb.so.1 -L"$TMP/lib" -lcommon \
  -o "$TMP/lib/libdb.so.1.0.0" "$TMP/db.o"
ln -s libdb.so.1.0.0 "$TMP/lib/libdb.so.1"
ln -s libdb.so.1 "$TMP/lib/libdb.so"
"$CPU_LD" --dynamic --stack-size=4096 --no-heap \
  -L"$TMP/lib" -lda -ldb -o "$TMP/diamond-main" "$TMP/diamond-main.o"
[ "`"$CPU_RUN" --library-path="$TMP/lib" --int-reg=r64@0x00018 "$TMP/diamond-main"`" = 42 ]

exit 0