python: Enforce absolute imports for Python 3 compatibility

Change-Id: Ia88d7fd472f7aed9b97df81468211384981bf6c6
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15983
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
diff --git a/src/arch/generic/BaseTLB.py b/src/arch/generic/BaseTLB.py
index b98b993..688117a 100644
--- a/src/arch/generic/BaseTLB.py
+++ b/src/arch/generic/BaseTLB.py
@@ -29,7 +29,7 @@
 #          Ivan Pizarro
 
 from m5.params import *
-from MemObject import MemObject
+from m5.objects.MemObject import MemObject
 
 class BaseTLB(MemObject):
     type = 'BaseTLB'
diff --git a/src/python/importer.py b/src/python/importer.py
index 224ab3b..20d168e 100644
--- a/src/python/importer.py
+++ b/src/python/importer.py
@@ -26,6 +26,9 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 # Simple importer that allows python to import data from a dict of
 # code objects.  The keys are the module path, and the items are the
 # filename and bytecode of the file.
diff --git a/src/python/m5/SimObject.py b/src/python/m5/SimObject.py
index 11330b4..5a86912 100644
--- a/src/python/m5/SimObject.py
+++ b/src/python/m5/SimObject.py
@@ -44,6 +44,7 @@
 #          Andreas Sandberg
 
 from __future__ import print_function
+from __future__ import absolute_import
 
 import sys
 from types import FunctionType, MethodType, ModuleType
diff --git a/src/python/m5/__init__.py b/src/python/m5/__init__.py
index 2730ea1..d97727c 100644
--- a/src/python/m5/__init__.py
+++ b/src/python/m5/__init__.py
@@ -26,6 +26,9 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 # Import useful subpackages of M5, but *only* when run as an m5
 # script.  This is mostly to keep backward compatibility with existing
 # scripts while allowing new SCons code to operate properly.
@@ -42,14 +45,14 @@
     in_gem5 = False
 
 if in_gem5:
-    import SimObject
-    import core
-    import objects
-    import params
-    import stats
-    import util
+    from . import SimObject
+    from . import core
+    from . import objects
+    from . import params
+    from . import stats
+    from . import util
 
-    from event import *
-    from main import main
-    from simulate import *
+    from .event import *
+    from .main import main
+    from .simulate import *
 
diff --git a/src/python/m5/core.py b/src/python/m5/core.py
index ab0ea57..4c94353 100644
--- a/src/python/m5/core.py
+++ b/src/python/m5/core.py
@@ -26,4 +26,7 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 from _m5.core import setOutputDir
diff --git a/src/python/m5/ext/__init__.py b/src/python/m5/ext/__init__.py
index a5bc8ef..f566a34 100644
--- a/src/python/m5/ext/__init__.py
+++ b/src/python/m5/ext/__init__.py
@@ -36,3 +36,6 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 # Authors: Glenn Bergmans
+
+from __future__ import print_function
+from __future__ import absolute_import
diff --git a/src/python/m5/ext/pyfdt/pyfdt.py b/src/python/m5/ext/pyfdt/pyfdt.py
index 3b3238e..3c78b03 100644
--- a/src/python/m5/ext/pyfdt/pyfdt.py
+++ b/src/python/m5/ext/pyfdt/pyfdt.py
@@ -19,6 +19,9 @@
 @author: Neil 'superna' Armstrong <superna9999@gmail.com>
 """
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 import string
 import os
 import json
diff --git a/src/python/m5/internal/params.py b/src/python/m5/internal/params.py
index 400e780..d06851a 100644
--- a/src/python/m5/internal/params.py
+++ b/src/python/m5/internal/params.py
@@ -38,6 +38,9 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 import inspect
 import _m5
 
diff --git a/src/python/m5/main.py b/src/python/m5/main.py
index eeaa947..fae04e7 100644
--- a/src/python/m5/main.py
+++ b/src/python/m5/main.py
@@ -54,8 +54,8 @@
     "gem5 is copyrighted software; use the --copyright option for details."
 
 def parse_options():
-    import config
-    from options import OptionParser
+    from . import config
+    from .options import OptionParser
 
     options = OptionParser(usage=usage, version=version,
                            description=brief_copyright)
@@ -203,15 +203,15 @@
 def main(*args):
     import m5
 
-    import core
-    import debug
-    import defines
-    import event
-    import info
-    import stats
-    import trace
+    from . import core
+    from . import debug
+    from . import defines
+    from . import event
+    from . import info
+    from . import stats
+    from . import trace
 
-    from util import inform, fatal, panic, isInteractive
+    from .util import inform, fatal, panic, isInteractive
 
     if len(args) == 0:
         options, arguments = parse_options()
@@ -286,7 +286,7 @@
         debug.help()
 
     if options.list_sim_objects:
-        import SimObject
+        from . import SimObject
         done = True
         print("SimObjects:")
         objects = list(SimObject.allClasses.keys())
diff --git a/src/python/m5/objects/__init__.py b/src/python/m5/objects/__init__.py
index 302bb6f..f80f6c5 100644
--- a/src/python/m5/objects/__init__.py
+++ b/src/python/m5/objects/__init__.py
@@ -26,6 +26,9 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 from m5.internal import params
 from m5.SimObject import *
 
diff --git a/src/python/m5/options.py b/src/python/m5/options.py
index 5b291b1..d34abfc 100644
--- a/src/python/m5/options.py
+++ b/src/python/m5/options.py
@@ -26,6 +26,9 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 import optparse
 import sys
 
diff --git a/src/python/m5/params.py b/src/python/m5/params.py
index 1470765..72cc0b2 100644
--- a/src/python/m5/params.py
+++ b/src/python/m5/params.py
@@ -68,9 +68,9 @@
 import time
 import math
 
-import proxy
-import ticks
-from util import *
+from . import proxy
+from . import ticks
+from .util import *
 
 def isSimObject(*args, **kwargs):
     return SimObject.isSimObject(*args, **kwargs)
@@ -2159,4 +2159,4 @@
            'MasterPort', 'SlavePort',
            'VectorMasterPort', 'VectorSlavePort']
 
-import SimObject
+from . import SimObject
diff --git a/src/python/m5/proxy.py b/src/python/m5/proxy.py
index 2a32500..346ed92 100644
--- a/src/python/m5/proxy.py
+++ b/src/python/m5/proxy.py
@@ -45,9 +45,12 @@
 #
 #####################################################################
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 import copy
 
-import params
+from . import params
 
 class BaseProxy(object):
     def __init__(self, search_self, search_up):
diff --git a/src/python/m5/simulate.py b/src/python/m5/simulate.py
index d72dee2..6f02327 100644
--- a/src/python/m5/simulate.py
+++ b/src/python/m5/simulate.py
@@ -51,14 +51,14 @@
 import _m5.core
 from _m5.stats import updateEvents as updateStatEvents
 
-import stats
-import SimObject
-import ticks
-import objects
+from . import stats
+from . import SimObject
+from . import ticks
+from . import objects
 from m5.util.dot_writer import do_dot, do_dvfs_dot
 
-from util import fatal
-from util import attrdict
+from .util import fatal
+from .util import attrdict
 
 # define a MaxTick parameter, unsigned 64 bit
 MaxTick = 2**64 - 1
diff --git a/src/python/m5/trace.py b/src/python/m5/trace.py
index ca98ebd..fe26325 100644
--- a/src/python/m5/trace.py
+++ b/src/python/m5/trace.py
@@ -26,5 +26,8 @@
 #
 # Authors: Nathan Binkert
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 # Export native methods to Python
 from _m5.trace import output, ignore, disable, enable
diff --git a/src/python/m5/util/__init__.py b/src/python/m5/util/__init__.py
index 341e54f..f7493be 100644
--- a/src/python/m5/util/__init__.py
+++ b/src/python/m5/util/__init__.py
@@ -45,14 +45,14 @@
 import re
 import sys
 
-import convert
-import jobfile
+from . import convert
+from . import jobfile
 
-from attrdict import attrdict, multiattrdict, optiondict
-from code_formatter import code_formatter
-from multidict import multidict
-from smartdict import SmartDict
-from sorteddict import SortedDict
+from .attrdict import attrdict, multiattrdict, optiondict
+from .code_formatter import code_formatter
+from .multidict import multidict
+from .smartdict import SmartDict
+from .sorteddict import SortedDict
 
 # panic() should be called when something happens that should never
 # ever happen regardless of what the user does (i.e., an acutal m5
diff --git a/src/python/m5/util/code_formatter.py b/src/python/m5/util/code_formatter.py
index 21bbcd7..8d48d0f 100644
--- a/src/python/m5/util/code_formatter.py
+++ b/src/python/m5/util/code_formatter.py
@@ -279,7 +279,7 @@
 __all__ = [ "code_formatter" ]
 
 if __name__ == '__main__':
-    from code_formatter import code_formatter
+    from .code_formatter import code_formatter
     f = code_formatter()
 
     class Foo(dict):
diff --git a/src/python/m5/util/dot_writer.py b/src/python/m5/util/dot_writer.py
index f368faa..730f0ed 100644
--- a/src/python/m5/util/dot_writer.py
+++ b/src/python/m5/util/dot_writer.py
@@ -57,6 +57,9 @@
 #
 #####################################################################
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 import m5, os, re
 from m5.SimObject import isRoot, isSimObjectVector
 from m5.params import PortRef, isNullPointer
diff --git a/src/python/m5/util/jobfile.py b/src/python/m5/util/jobfile.py
index 45214a0..e19c62e 100644
--- a/src/python/m5/util/jobfile.py
+++ b/src/python/m5/util/jobfile.py
@@ -27,6 +27,7 @@
 # Authors: Nathan Binkert
 
 from __future__ import print_function
+from __future__ import absolute_import
 
 import sys
 
diff --git a/src/python/m5/util/pybind.py b/src/python/m5/util/pybind.py
index f666547..4b5e03d 100644
--- a/src/python/m5/util/pybind.py
+++ b/src/python/m5/util/pybind.py
@@ -35,6 +35,9 @@
 #
 # Authors: Andreas Sandberg
 
+from __future__ import print_function
+from __future__ import absolute_import
+
 from abc import *
 
 class PyBindExport(object):
diff --git a/src/python/m5/util/smartdict.py b/src/python/m5/util/smartdict.py
index b8127b1..3cfe329 100644
--- a/src/python/m5/util/smartdict.py
+++ b/src/python/m5/util/smartdict.py
@@ -41,9 +41,11 @@
 # rather than a normal value, and (c) coerce values written to the
 # dict to be strings.
 
+from __future__ import print_function
+from __future__ import absolute_import
 
-from convert import *
-from attrdict import attrdict
+from .convert import *
+from .attrdict import attrdict
 
 class Variable(str):
     """Intelligent proxy class for SmartDict.  Variable will use the
diff --git a/src/python/m5/util/sorteddict.py b/src/python/m5/util/sorteddict.py
index 28c9c60..25d6d39 100644
--- a/src/python/m5/util/sorteddict.py
+++ b/src/python/m5/util/sorteddict.py
@@ -25,6 +25,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 from __future__ import print_function
+from __future__ import absolute_import
 
 from bisect import bisect_left, bisect_right
 
diff --git a/src/python/m5/util/terminal.py b/src/python/m5/util/terminal.py
index 00f8b70..fd4392e 100644
--- a/src/python/m5/util/terminal.py
+++ b/src/python/m5/util/terminal.py
@@ -27,6 +27,7 @@
 # Author: Steve Reinhardt
 
 from __future__ import print_function
+from __future__ import absolute_import
 
 import sys