sim: Move the draining interface into a separate base class

This patch moves the draining interface from SimObject to a separate
class that can be used by any object needing draining. However,
objects not visible to the Python code (i.e., objects not deriving
from SimObject) still depend on their parents informing them when to
drain. This patch also gets rid of the CountedDrainEvent (which isn't
really an event) and replaces it with a DrainManager.

src/python/SConscript

@@ -66,6 +66,7 @@ PySource('m5.util', 'm5/util/terminal.py')
 
 SwigSource('m5.internal', 'swig/core.i')
 SwigSource('m5.internal', 'swig/debug.i')
+SwigSource('m5.internal', 'swig/drain.i')
 SwigSource('m5.internal', 'swig/event.i')
 SwigSource('m5.internal', 'swig/pyobject.i')
 SwigSource('m5.internal', 'swig/range.i')

src/python/m5/SimObject.py

@@ -123,7 +123,8 @@ class MetaSimObject(type):
                       'cxx_class' : str,
                       'cxx_type' : str,
                       'cxx_header' : str,
-                      'type' : str }
+                      'type' : str,
+                      'cxx_bases' : list }
     # Attributes that can be set any time
     keywords = { 'check' : FunctionType }
 
@@ -148,6 +149,8 @@ class MetaSimObject(type):
                 value_dict[key] = val
         if 'abstract' not in value_dict:
             value_dict['abstract'] = False
+        if 'cxx_bases' not in value_dict:
+            value_dict['cxx_bases'] = []
         cls_dict['_value_dict'] = value_dict
         cls = super(MetaSimObject, mcls).__new__(mcls, name, bases, cls_dict)
         if 'type' in value_dict:
@@ -414,6 +417,7 @@ class MetaSimObject(type):
         code('%module(package="m5.internal") param_$cls')
         code()
         code('%{')
+        code('#include "sim/sim_object.hh"')
         code('#include "params/$cls.hh"')
         for param in params:
             param.cxx_predecls(code)
@@ -458,7 +462,17 @@ using std::ptrdiff_t;
         code('%nodefault $classname;')
         code('class $classname')
         if cls._base:
-            code('    : public ${{cls._base.cxx_class}}')
+            bases = [ cls._base.cxx_class ] + cls.cxx_bases
+        else:
+            bases = cls.cxx_bases
+        base_first = True
+        for base in bases:
+            if base_first:
+                code('    : public ${{base}}')
+                base_first = False
+            else:
+                code('    , public ${{base}}')
+
         code('{')
         code('  public:')
         cls.export_methods(code)
@@ -581,30 +595,25 @@ class SimObject(object):
     abstract = True
     cxx_header = "sim/sim_object.hh"
 
+    cxx_bases = [ "Drainable" ]
+
     @classmethod
     def export_method_swig_predecls(cls, code):
         code('''
 %include <std_string.i>
+
+%import "python/swig/drain.i"
 ''')
 
     @classmethod
     def export_methods(cls, code):
         code('''
-    enum State {
-      Running,
-      Draining,
-      Drained
-    };
-
     void init();
     void loadState(Checkpoint *cp);
     void initState();
     void regStats();
     void resetStats();
     void startup();
-
-    unsigned int drain(Event *drain_event);
-    void resume();
 ''')
 
     # Initialize new instance.  For objects with SimObject-valued

src/python/m5/__init__.py

@@ -51,3 +51,4 @@ if internal:
     from event import *
     from main import main
     from simulate import *
+

src/python/m5/internal/__init__.py

@@ -31,3 +31,4 @@ import debug
 import event
 import stats
 import trace
+from drain import DrainManager, Drainable

src/python/m5/simulate.py

@@ -169,19 +169,19 @@ def doDrain(root):
 # be drained.
 def drain(root):
     all_drained = False
-    drain_event = internal.event.createCountedDrain()
-    unready_objs = sum(obj.drain(drain_event) for obj in root.descendants())
+    dm = internal.drain.createDrainManager()
+    unready_objs = sum(obj.drain(dm) for obj in root.descendants())
     # If we've got some objects that can't drain immediately, then simulate
     if unready_objs > 0:
-        drain_event.setCount(unready_objs)
+        dm.setCount(unready_objs)
         simulate()
     else:
         all_drained = True
-    internal.event.cleanupCountedDrain(drain_event)
+    internal.drain.cleanupDrainManager(dm)
     return all_drained
 
 def resume(root):
-    for obj in root.descendants(): obj.resume()
+    for obj in root.descendants(): obj.drainResume()
 
 def checkpoint(dir):
     root = objects.Root.getInstance()

src/python/swig/drain.i

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2012 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * 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.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+%module(package="m5.internal") drain
+
+%{
+#include "sim/drain.hh"
+%}
+
+%nodefaultctor Drainable;
+
+%include "sim/drain.hh"
+
+%inline %{
+
+DrainManager *
+createDrainManager()
+{
+    return new DrainManager();
+}
+
+void
+cleanupDrainManager(DrainManager *drain_manager)
+{
+    assert(drain_manager);
+    assert(drain_manager->getCount() == 0);
+    delete drain_manager;
+}
+
+%}

src/python/swig/event.i

@@ -81,11 +81,6 @@
 // This must follow eventq.hh
 %include "python/swig/pyevent.hh"
 
-struct CountedDrainEvent : public Event
-{
-    void setCount(int _count);
-};
-
 // minimal definition of SimExitEvent interface to wrap
 class SimLoopExitEvent : public Event
 {

src/python/swig/pyevent.cc

@@ -65,22 +65,3 @@ PythonEvent::process()
     // reference count must be decremented.
     Py_DECREF(object);
 }
-
-CountedDrainEvent *
-createCountedDrain()
-{
-    return new CountedDrainEvent();
-}
-
-void
-cleanupCountedDrain(Event *counted_drain)
-{
-    CountedDrainEvent *event =
-        dynamic_cast<CountedDrainEvent *>(counted_drain);
-    if (event == NULL) {
-        fatal("Called cleanupCountedDrain() on an event that was not "
-              "a CountedDrainEvent.");
-    }
-    assert(event->getCount() == 0);
-    delete event;
-}

src/python/swig/pyevent.hh

@@ -49,7 +49,4 @@ class PythonEvent : public Event
     virtual void process();
 };
 
-CountedDrainEvent *createCountedDrain();
-void cleanupCountedDrain(Event *counted_drain);
-
 #endif // __PYTHON_SWIG_PYEVENT_HH__