[gcmole] Add subparsers

This will enable running the main gcmole script in different modes
in the future, full run (this CL), later suspect generation only and
analysis only.

Bug: v8:12660
Change-Id: Ica87366fb3c5b6e238f5a1efaf347ebbeb01003a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4026062
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84357}

tools/gcmole/gcmole.py

@@ -524,8 +524,9 @@ def main(argv):
     default_gcmole_dir = relative_parents(Path(argv[0]))
   if default_gcmole_dir or not default_gcmole_dir.exists():
     default_gcmole_dir = default_root_dir / 'tools' / 'gcmole'
+  default_clang_bin_dir = default_gcmole_dir / 'gcmole-tools/bin'
 
-  parser = argparse.ArgumentParser()
+  def add_common_args(parser):
     archs = list(ARCHITECTURES.keys())
     parser.add_argument(
         "--v8-root-dir",
@@ -539,7 +540,6 @@ def main(argv):
         choices=archs,
         help="Tested CPU architecture. Choices: {}".format(archs),
         metavar="CPU")
-  default_clang_bin_dir = default_gcmole_dir / 'gcmole-tools/bin'
     parser.add_argument(
         "--clang-bin-dir",
         metavar="DIR",
@@ -608,6 +608,14 @@ def main(argv):
         default=False,
         help="Test gcmole on tools/gcmole/gcmole-test.cc")
 
+  parser = argparse.ArgumentParser()
+  subps = parser.add_subparsers()
+
+  subp = subps.add_parser(
+      "full", description="Run both gcmole analysis passes.")
+  add_common_args(subp)
+  subp.set_defaults(func=full_run)
+
   options = parser.parse_args(argv[1:])
 
   verify_and_convert_dirs(parser, options, default_gcmole_dir,
@@ -616,6 +624,10 @@ def main(argv):
   prepare_gcmole_files(options)
   verify_build_config(parser, options)
 
+  options.func(options)
+
+
+def full_run(options):
   any_errors_found = False
   if not test_run(options):
     any_errors_found = True

tools/gcmole/run-gcmole.py

@@ -43,6 +43,7 @@ proc = subprocess.Popen(
     [
         sys.executable,
         GCMOLE_PY,
+        "full",
         "--v8-build-dir=%s" % os.path.join(V8_ROOT_DIR, 'out', 'build'),
         "--v8-target-cpu=%s" % sys.argv[1],
         "--clang-plugins-dir=%s" % CLANG_PLUGINS,