Add script to generate a code size report

This script runs the specified size command (e.g. arm-none-eabi-size) on
the specified library (e.g. libtfpsacrypto.a).

Signed-off-by: David Horstmann <david.horstmann@arm.com>

Author: davidhorstmann-arm

scripts/generate_code_size_report.py

@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+"""Generate a code size report for the supplied library file, using the given
+size tool, and write it in JSON format to the given output file.
+"""
+
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+
+import argparse
+import json
+import subprocess
+import sys
+
+def get_size_output(size_cmd: str, library_file: str):
+    """Run the size command on the library and get its output"""
+    output = subprocess.check_output([size_cmd, library_file])
+    return str(output, 'UTF-8')
+
+def size_breakdown(size_output: str):
+    """Convert the output of the size command to a dictionary like the following:
+    {'filename.c.obj' : {'text': 123, 'data': 456, 'bss': 789}}"""
+
+    sizes = {}
+
+    for line in size_output.splitlines()[1:]:
+        row = line.split()
+        obj_file_name = row[5]
+        text_size = int(row[0])
+        data_size = int(row[1])
+        bss_size = int(row[2])
+
+        sizes[obj_file_name] = {'text': text_size, 'data': data_size, 'bss': bss_size}
+
+    return sizes
+
+def write_out_results(sizes: dict, output_file: str):
+    """Write out the sizes in JSON to the output file"""
+    sizes_json = json.dumps(sizes, indent=4)
+
+    with open(output_file, "w") as out:
+        out.write(sizes_json)
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Generate a code size report in JSON format')
+
+    parser.add_argument("-o", "--output-file",
+                        help="Filename of the report to generate",
+                        default='code_size.json')
+
+    parser.add_argument("-s", "--size-cmd",
+                        help="Size command to use (e.g. arm-none-eabi-size)",
+                        required=True)
+
+    parser.add_argument("-l", "--library-file",
+                        help="Library file to generate report from",
+                        required=True)
+
+    args = parser.parse_args()
+
+    sizes = size_breakdown(get_size_output(args.size_cmd, args.library_file))
+
+    write_out_results(sizes, args.output_file)
+
+if __name__ == "__main__":
+    main()
+