Add gen_externs.py tool

tools/gen_externs.py

@@ -0,0 +1,48 @@
+import argparse
+import os
+from pathlib import Path
+import platform
+import re
+import subprocess
+import sys
+
+def eprint(*args, **kwargs):
+    print(*args, file=sys.stderr, **kwargs)
+
+parser = argparse.ArgumentParser(description='Generates .inc files with all necessary external symbols')
+parser.add_argument('file', help='Assembly source file')
+
+tools_dir = Path(os.path.dirname(os.path.realpath(__file__)))
+as_path = tools_dir / 'mwccarm' / '2.0' / 'sp1p5' / 'mwasmarm.exe'
+root_dir = tools_dir.parent
+include_dir = root_dir / 'asm'
+
+if platform.system() == 'Windows': _as = [str(as_path)]
+else: _as = ['wine', str(as_path)]
+
+args = parser.parse_args()
+
+_as.extend([
+    '-nolink',
+    '-proc', 'arm5te',
+    '-msgstyle', 'gcc',
+    '-dis',
+    f'-I{include_dir}',
+    args.file
+])
+
+try:
+    output = subprocess.check_output(_as, stderr=subprocess.DEVNULL)
+except subprocess.CalledProcessError as e:
+    output = e.stdout.decode()
+
+symbols: list[str] = re.findall(r'Unknown identifier, (?:[\r\n]+\S+ )?(\S+)', output)
+if len(symbols) == 0:
+    eprint("No symbols needed")
+    exit(0)
+
+print('#pragma once')
+for i, symbol in enumerate(symbols):
+    # Avoid duplicates
+    if symbol in symbols[:i]: continue
+    print(f'.extern {symbol}')