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>
2 files changed