util: Allow MyPy stubgen to aid Pylance IntelliSense

Change-Id: I42fe177e5ae428afd0f23ea482b6af5b7d3ecaf9

requirements.txt

@@ -1 +1,2 @@
 pre-commit==2.20.0
+mypy==1.5.1

util/gem5-stubgen.py

@@ -0,0 +1,63 @@
+# Copyright (c) 2023 The Regents of the University of California
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+from mypy.stubgen import generate_stubs, parse_options
+
+"""
+This allows us to generate stubs for the modules in gem5. The output will be
+a "typings" directory which can be used by Pylance (Python IntelliSense) to
+infer typings in Visual Studio Code.
+
+Note: A "typings" directory in the root of the workspace is the default
+location for Pylance to look for typings. This can be changed via
+`python.analysis.stubPath` in "settings.json".
+
+Usage
+=====
+
+```sh
+pip3 install -r requirements.txt
+scons build/ALL/gem5.opt -j$(nproc)
+./build/ALL/gem5.opt util/gem5-stubgen.py
+```
+
+"""
+
+if __name__ == "__m5_main__":
+    import m5
+
+    # get a list of all modules exported by gem5
+    modules = m5.__spec__.loader_state
+
+    options = parse_options(
+        ("--module " + " --module ".join(modules)).split(" ")
+        + ["--output", "typings"]
+    )
+    generate_stubs(options)
+
+if __name__ == "__main__":
+    print("Error: This script is meant to be run with the gem5 binary")
+    exit(1)