Replace circular includes perl script with python

tools/circular_includes.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+"""
+Script for reporting circular #includes in pre-processed sel4 source.
+Exits with a status of 0 if no circular dependencies are found, otherwise
+prints circular dependency and exits with a status of -1.
+"""
+
+import sys
+import re
+
+def main():
+    """
+    Reads pre-processed sel4 source from standard input.
+    If a circular dependency is found, the chain of includes
+    resulting in the loop is printed out.
+    """
+
+    kernel_all_re = re.compile(r'^# 1 "kernel_all\.c"')
+    header_re = re.compile(r'^# (\d+) "(.*\..)"')
+
+    file_stack = []
+
+    for line in sys.stdin:
+
+        if kernel_all_re.match(line):
+            continue
+
+        match = header_re.match(line)
+
+        if match is None:
+            continue
+
+        depth = int(match.group(1))
+        header = match.group(2)
+
+        if depth == 1:
+            # found a new header
+            if header in file_stack:
+                print("Circular includes found:")
+                print("\n".join(file_stack))
+                print(header)
+                return -1
+            else:
+                file_stack.append(header)
+        else:
+            # popped back up to an earlier header
+            while file_stack[-1] != header:
+                file_stack.pop()
+
+    return 0
+
+if __name__ == "__main__":
+
+    if len(sys.argv) != 1:
+        print("Usage: %s < path/to/kernel_all.c_pp" % sys.argv[0])
+        print(__doc__)
+        sys.exit(-1)
+
+    sys.exit(main())