1 files changed, 69 insertions, 0 deletions
diff --git a/tools/migration/legacy_fields_migrator.py b/tools/migration/legacy_fields_migrator.py
new file mode 100644
index 0000000..cc1bb41
--- /dev/null
+++ b/tools/migration/legacy_fields_migrator.py
@@ -0,0 +1,69 @@
+"""Script migrating legacy CROSSTOOL fields into features.
+
+This script migrates the CROSSTOOL to use only the features to describe C++
+command lines. It is intended to be added as a last step of CROSSTOOL generation
+pipeline. Since it doesn't retain comments, we assume CROSSTOOL owners will want
+to migrate their pipeline manually.
+"""
+
+# Tracking issue: https://github.com/bazelbuild/bazel/issues/5187
+#
+# Since C++ rules team is working on migrating CROSSTOOL from text proto into
+# Starlark, we advise CROSSTOOL owners to wait for the CROSSTOOL -> Starlark
+# migrator before they invest too much time into fixing their pipeline. Tracking
+# issue for the Starlark effort is
+# https://github.com/bazelbuild/bazel/issues/5380.
+
+from absl import app
+from absl import flags
+from google.protobuf import text_format
+from third_party.com.github.bazelbuild.bazel.src.main.protobuf import crosstool_config_pb2
+from tools.migration.legacy_fields_migration_lib import migrate_legacy_fields
+import os
+
+flags.DEFINE_string("input", None, "Input CROSSTOOL file to be migrated")
+flags.DEFINE_string("output", None,
+                    "Output path where to write migrated CROSSTOOL.")
+flags.DEFINE_boolean("inline", None, "Overwrite --input file")
+
+
+def main(unused_argv):
+  crosstool = crosstool_config_pb2.CrosstoolRelease()
+
+  input_filename = flags.FLAGS.input
+  output_filename = flags.FLAGS.output
+  inline = flags.FLAGS.inline
+
+  if not input_filename:
+    raise app.UsageError("ERROR --input unspecified")
+  if not output_filename and not inline:
+    raise app.UsageError("ERROR --output unspecified and --inline not passed")
+  if output_filename and inline:
+    raise app.UsageError("ERROR both --output and --inline passed")
+
+  with open(to_absolute_path(input_filename), "r") as f:
+    input_text = f.read()
+
+  text_format.Merge(input_text, crosstool)
+
+  migrate_legacy_fields(crosstool)
+  output_text = text_format.MessageToString(crosstool)
+
+  resolved_output_filename = to_absolute_path(
+      input_filename if inline else output_filename)
+  with open(resolved_output_filename, "w") as f:
+    f.write(output_text)
+
+def to_absolute_path(path):
+  path = os.path.expanduser(path)
+  if os.path.isabs(path):
+    return path
+  else:
+    if "BUILD_WORKING_DIRECTORY" in os.environ:
+      return os.path.join(os.environ["BUILD_WORKING_DIRECTORY"], path)
+    else:
+      return path
+
+
+if __name__ == "__main__":
+  app.run(main)