1 files changed, 133 insertions, 0 deletions
diff --git a/pw_build/py/pw_build/merge_profraws.py b/pw_build/py/pw_build/merge_profraws.py
new file mode 100755
index 000000000..17681e0c0
--- /dev/null
+++ b/pw_build/py/pw_build/merge_profraws.py
@@ -0,0 +1,133 @@
+# Copyright 2023 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Merge multiple profraws together using llvm-profdata."""
+
+import argparse
+import enum
+import json
+import logging
+import subprocess
+import sys
+from pathlib import Path
+from typing import Dict, Any
+
+_LOG = logging.getLogger(__name__)
+
+
+class FailureMode(enum.Enum):
+    ANY = 'any'
+    ALL = 'all'
+
+    def __str__(self):
+        return self.value
+
+
+def _parse_args() -> Dict[str, Any]:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        '--llvm-profdata-path',
+        type=Path,
+        required=True,
+        help='Path to the llvm-profdata binary to use for merging.',
+    )
+    parser.add_argument(
+        '--test-metadata-path',
+        type=Path,
+        required=True,
+        help='Path to the *.test_metadata.json file that describes all of the '
+        'tests being used to generate a coverage report.',
+    )
+    parser.add_argument(
+        '--profdata-path',
+        type=Path,
+        required=True,
+        help='Path for the output merged profdata file to use with generating a'
+        ' coverage report for the tests described in --test-metadata.',
+    )
+    parser.add_argument(
+        '--depfile-path',
+        type=Path,
+        required=True,
+        help='Path for the output depfile to convey the extra input '
+        'requirements from parsing --test-metadata.',
+    )
+    parser.add_argument(
+        '--failure-mode',
+        type=FailureMode,
+        choices=list(FailureMode),
+        required=False,
+        default=FailureMode.ANY,
+        help='Sets the llvm-profdata --failure-mode option.',
+    )
+    return vars(parser.parse_args())
+
+
+def merge_profraws(
+    llvm_profdata_path: Path,
+    test_metadata_path: Path,
+    profdata_path: Path,
+    depfile_path: Path,
+    failure_mode: FailureMode,
+) -> int:
+    """Merge multiple profraws together using llvm-profdata."""
+
+    # Open the test_metadata_path, parse it to JSON, and extract out the
+    # profraws.
+    test_metadata = json.loads(test_metadata_path.read_text())
+    profraw_paths = [
+        str(obj['path'])
+        for obj in test_metadata
+        if 'type' in obj and obj['type'] == 'profraw'
+    ]
+
+    # Generate merged profdata.
+    command = [
+        str(llvm_profdata_path),
+        'merge',
+        '--sparse',
+        '--failure-mode',
+        str(failure_mode),
+        '-o',
+        str(profdata_path),
+    ] + profraw_paths
+
+    _LOG.info('')
+    _LOG.info(' '.join(command))
+    _LOG.info('')
+
+    output = subprocess.run(command)
+    if output.returncode != 0:
+        return output.returncode
+
+    # Generate the depfile that describes the dependency on the profraws used to
+    # create profdata_path.
+    depfile_path.write_text(
+        ''.join(
+            [
+                str(profdata_path),
+                ': \\\n',
+                *[str(path) + ' \\\n' for path in profraw_paths],
+            ]
+        )
+    )
+
+    return 0
+
+
+def main() -> int:
+    return merge_profraws(**_parse_args())
+
+
+if __name__ == "__main__":
+    sys.exit(main())