python,scons: Add a dummy m5/objects/SimObject.py.

This serves two purposes. First, it's a way to declare the base
SimObject class and params using the SimObject() SCons mechanism, while
the actual class still lives at m5/SimObject.py.

Second, it alleviates a very old inconsistency where *most* SimObjects
are imported using the m5.objects.Foo path, except SimObject itself
which lives under m5.SimObject. With this change, it will live under
both, more or less.

It may be possible to remove the inconsistency entirely in the future
and move m5.SimObject entirely to m5.objects.SimObject and only declare
it with SCons's SimObject(), but that won't quite work during this
transitional period, and it wouldn't give users a chance to move over to
the new name.

Change-Id: Ic714bacfaef73d1116ab7ff716cf19b7ce4b67e1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49408
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/python/SConscript b/src/python/SConscript
index dd02dd3..9f1cddb 100644
--- a/src/python/SConscript
+++ b/src/python/SConscript
@@ -258,3 +258,6 @@
 Source('pybind11/event.cc', add_tags='python')
 Source('pybind11/object_file.cc', add_tags='python')
 Source('pybind11/stats.cc', add_tags='python')
+
+SimObject('m5/objects/SimObject.py', sim_objects=['SimObject'],
+        enums=['ByteOrder'])
diff --git a/src/python/m5/objects/SimObject.py b/src/python/m5/objects/SimObject.py
new file mode 100644
index 0000000..efec5eb
--- /dev/null
+++ b/src/python/m5/objects/SimObject.py
@@ -0,0 +1,29 @@
+# Copyright 2020 Google, Inc.
+#
+# 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 m5.SimObject import *
+# The ByteOrder enum is defined in params. Expose it here so we can declare it
+# to SCons, since there's no normal SimObject file to make it a part of.
+from m5.params import ByteOrder