Update GaCy-GO

tools/inspect_luau_v4.py

@@ -0,0 +1,92 @@
+"""Read version-4 Luau chunks without executing them.
+
+Layout: upstream Luau VM/src/lvmload.cpp, Common/include/Luau/Bytecode.h.
+Only v4/type1 is accepted; later/custom layouts fail instead of guessing.
+"""
+import argparse
+import json
+import struct
+from pathlib import Path
+
+
+def inspect(path):
+    data = Path(path).read_bytes()
+    offset = 0
+
+    def read(size):
+        nonlocal offset
+        value = data[offset:offset + size]
+        if len(value) != size:
+            raise ValueError('truncated chunk')
+        offset += size
+        return value
+
+    def byte():
+        return read(1)[0]
+
+    def integer():
+        value, shift = 0, 0
+        while True:
+            v = byte()
+            value |= (v & 127) << shift
+            if v < 128:
+                return value
+            shift += 7
+            if shift > 28:
+                raise ValueError('oversized integer')
+
+    if (byte(), byte()) != (4, 1):
+        raise ValueError('only Luau v4/type1 supported')
+    strings = [None] + [read(integer()).decode('utf-8', 'replace') for _ in range(integer())]
+    protos = []
+    for index in range(integer()):
+        stack, params, upvalues, vararg, flags = [byte() for _ in range(5)]
+        read(integer())
+        code = [struct.unpack('<I', read(4))[0] for _ in range(integer())]
+        constants = []
+        for _ in range(integer()):
+            kind = byte()
+            if kind == 0:
+                value = None
+            elif kind == 1:
+                value = bool(byte())
+            elif kind == 2:
+                value = struct.unpack('<d', read(8))[0]
+            elif kind == 3:
+                value = strings[integer()]
+            elif kind == 4:
+                value = {'import': struct.unpack('<I', read(4))[0]}
+            elif kind == 5:
+                value = {'table_keys': [integer() for _ in range(integer())]}
+            elif kind == 6:
+                value = {'closure': integer()}
+            else:
+                raise ValueError(f'unsupported constant {kind}')
+            constants.append(value)
+        children = [integer() for _ in range(integer())]
+        line, name = integer(), strings[integer()]
+        if byte():
+            gap = byte()
+            read(len(code))
+            read((((len(code) - 1) >> gap) + 1) * 4)
+        locals_ = []
+        ups = []
+        if byte():
+            for _ in range(integer()):
+                locals_.append([strings[integer()], integer(), integer(), byte()])
+            ups = [strings[integer()] for _ in range(integer())]
+        protos.append(dict(index=index, name=name, line=line, stack=stack,
+                           params=params, upvalues=ups, children=children,
+                           constants=constants, code=code, locals=locals_))
+    main = integer()
+    if offset != len(data):
+        raise ValueError(f'unconsumed bytes: {len(data) - offset}')
+    return dict(main=main, strings=strings, protos=protos)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('path')
+    parser.add_argument('--output', required=True)
+    args = parser.parse_args()
+    Path(args.output).write_text(json.dumps(inspect(args.path), indent=2, ensure_ascii=False), encoding='utf-8')