From 39f0bcd9aff4851f91d851bd07f2078dc1891857 Mon Sep 17 00:00:00 2001
From: "Bobby R. Bruce" <bbruce@ucdavis.edu>
Date: Tue, 12 Sep 2023 14:51:59 -0700
Subject: [PATCH] python: Mimic Python 3's `-P` flag in gem5

Python 3's `-P` flag, when set, means `sys.path` is not prepended with
potentially unsafe paths:
https://docs.python.org/3/using/cmdline.html#cmdoption-P

This patch allows gem5 to mimic this. This is necesssary when using
`mypy.stubgen` as it expects the Python Interpreter to have the `-P`
flag.

Change-Id: I456c8001d3ee1e806190dc37142566d50d54cc90
---
 src/python/m5/main.py | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/python/m5/main.py b/src/python/m5/main.py
index e07e9562ab..3c418ba29b 100644
--- a/src/python/m5/main.py
+++ b/src/python/m5/main.py
@@ -193,6 +193,14 @@ def parse_options():
         callback=collect_args,
     )
 
+    option(
+        "-P",
+        action="store_true",
+        default=False,
+        help="Don't prepend the script directory to the system path. "
+        "Mimics Python 3's `-P` option.",
+    )
+
     option(
         "-s",
         action="store_true",
@@ -601,7 +609,11 @@ def main():
         sys.argv = ["-c"] + options.c[1]
         scope = {"__name__": "__m5_main__"}
     else:
-        sys.path = [os.path.dirname(sys.argv[0])] + sys.path
+        # If `-P` was used (`options.P == true`), don't prepend the script
+        # directory to the `sys.path`. This mimics Python 3's `-P` option
+        # (https://docs.python.org/3/using/cmdline.html#cmdoption-P).
+        if not options.P:
+            sys.path = [os.path.dirname(sys.argv[0])] + sys.path
         filename = sys.argv[0]
         filedata = open(filename, "r").read()
         filecode = compile(filedata, filename, "exec")