Integrate Python configuration script parsing into m5 itself.

SConscript:
    Add pyconfig/{pyconfig,code}.cc
    Add list of object description (.od) files.
    Include pyconfig/SConscript.
base/inifile.cc:
    Get rid of CPP_PIPE... it never really worked anyway.
base/inifile.hh:
    Make load(ifstream&) method public so pyconfig
    code can call it.
sim/main.cc:
    Handle Python config scripts (end in '.py' instead of '.ini').
sim/pyconfig/m5configbase.py:
    Add license.
    Fix minor __setattr__ problem (2.3 related?)

--HG--
rename : util/config/m5configbase.py => sim/pyconfig/m5configbase.py
extra : convert_revision : 5e004922f950bfdefced333285584b80ad7ffb83

3 files changed, 802 insertions, 8 deletions

diff --git a/sim/main.cc b/sim/main.cc
index 54c74fd1a..2a0427303 100644
--- a/sim/main.cc
+++ b/sim/main.cc
@@ -56,6 +56,7 @@
 #include "sim/stat_control.hh"
 #include "sim/stats.hh"
 #include "sim/universe.hh"
+#include "sim/pyconfig/pyconfig.hh"
 
 using namespace std;
 
@@ -340,15 +341,35 @@ main(int argc, char **argv)
         else {
             // no '-', treat as config file name
 
-            // If we haven't loaded default.ini yet, and we want to,
-            // now is the time.  Can't do it sooner because we need to
-            // look for '-n', can't do it later since we want
-            // default.ini loaded first (so that any other settings
-            // override it).
-            handleDefaultIni(loadDefaultIni, cppArgs);
+            // make STL string out of file name
+            string filename(arg_str);
 
-            if (!simConfigDB.loadCPP(arg_str, cppArgs)) {
-                cprintf("Error processing file %s\n", arg_str);
+            int ext_loc = filename.rfind(".");
+
+            string ext =
+                (ext_loc != string::npos) ? filename.substr(ext_loc) : "";
+
+            if (ext == ".ini") {
+                // If we haven't loaded default.ini yet, and we want to,
+                // now is the time.  Can't do it sooner because we need to
+                // look for '-n', can't do it later since we want
+                // default.ini loaded first (so that any other settings
+                // override it).
+                handleDefaultIni(loadDefaultIni, cppArgs);
+
+                if (!simConfigDB.loadCPP(filename, cppArgs)) {
+                    cprintf("Error processing file %s\n", filename);
+                    exit(1);
+                }
+            } else if (ext == ".py") {
+                if (!loadPythonConfig(filename, &simConfigDB)) {
+                    cprintf("Error processing file %s\n", filename);
+                    exit(1);
+                }
+            }
+            else {
+                cprintf("Config file name '%s' must end in '.py' or '.ini'.\n",
+                        filename);
                 exit(1);
             }
         }
diff --git a/sim/pyconfig/SConscript b/sim/pyconfig/SConscript
new file mode 100644
index 000000000..7661e7603
--- /dev/null
+++ b/sim/pyconfig/SConscript
@@ -0,0 +1,50 @@
+# -*- mode:python -*-
+
+# Copyright (c) 2004 The Regents of The University of Michigan
+# All rights reserved.
+#
+# 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.
+
+import os
+
+Import('env', 'obj_desc_files')
+
+my_obj_desc_files = map(lambda x: '../../' + x, obj_desc_files)
+
+env.Command('m5odescs.py', my_obj_desc_files,
+            '$TARGET.srcdir/load_odescs.py $_CPPDEFFLAGS $SOURCES $TARGET')
+
+# Python modules to encapsulate
+string_module_bases = Split('m5config m5configbase m5odescs')
+string_modules = map(lambda x: x + '_as_string.py', string_module_bases)
+
+for m in string_module_bases:
+    env.Command(m + '_as_string.py', m + '.py',
+                '$TARGET.srcdir/make_string_module.py $SOURCE $TARGET')
+
+embedded_py_files = Split('string_importer.py') + string_modules
+
+env.Command('code.cc', embedded_py_files,
+            '$TARGET.srcdir/make_c_file.py pyconfig_code $SOURCES $TARGET')
+
diff --git a/sim/pyconfig/m5configbase.py b/sim/pyconfig/m5configbase.py
new file mode 100644
index 000000000..66660994e
--- /dev/null
+++ b/sim/pyconfig/m5configbase.py
@@ -0,0 +1,723 @@
+# Copyright (c) 2004 The Regents of The University of Michigan
+# All rights reserved.
+#
+# 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 __future__ import generators
+
+import os
+import re
+import sys
+
+#####################################################################
+#
+# M5 Python Configuration Utility
+#
+# The basic idea is to write simple Python programs that build Python
+# objects corresponding to M5 SimObjects for the deisred simulation
+# configuration.  For now, the Python emits a .ini file that can be
+# parsed by M5.  In the future, some tighter integration between M5
+# and the Python interpreter may allow bypassing the .ini file.
+#
+# Each SimObject class in M5 is represented by a Python class with the
+# same name.  The Python inheritance tree mirrors the M5 C++ tree
+# (e.g., SimpleCPU derives from BaseCPU in both cases, and all
+# SimObjects inherit from a single SimObject base class).  To specify
+# an instance of an M5 SimObject in a configuration, the user simply
+# instantiates the corresponding Python object.  The parameters for
+# that SimObject are given by assigning to attributes of the Python
+# object, either using keyword assignment in the constructor or in
+# separate assignment statements.  For example:
+#
+# cache = BaseCache('my_cache', root, size=64*K)
+# cache.hit_latency = 3
+# cache.assoc = 8
+#
+# (The first two constructor arguments specify the name of the created
+# cache and its parent node in the hierarchy.)
+#
+# The magic lies in the mapping of the Python attributes for SimObject
+# classes to the actual SimObject parameter specifications.  This
+# allows parameter validity checking in the Python code.  Continuing
+# the example above, the statements "cache.blurfl=3" or
+# "cache.assoc='hello'" would both result in runtime errors in Python,
+# since the BaseCache object has no 'blurfl' parameter and the 'assoc'
+# parameter requires an integer, respectively.  This magic is done
+# primarily by overriding the special __setattr__ method that controls
+# assignment to object attributes.
+#
+# The Python module provides another class, ConfigNode, which is a
+# superclass of SimObject.  ConfigNode implements the parent/child
+# relationship for building the configuration hierarchy tree.
+# Concrete instances of ConfigNode can be used to group objects in the
+# hierarchy, but do not correspond to SimObjects themselves (like a
+# .ini section with "children=" but no "type=".
+#
+# Once a set of Python objects have been instantiated in a hierarchy,
+# calling 'instantiate(obj)' (where obj is the root of the hierarchy)
+# will generate a .ini file.  See simple-4cpu.py for an example
+# (corresponding to m5-test/simple-4cpu.ini).
+#
+#####################################################################
+
+#####################################################################
+#
+# ConfigNode/SimObject classes
+#
+# The Python class hierarchy rooted by ConfigNode (which is the base
+# class of SimObject, which in turn is the base class of all other M5
+# SimObject classes) has special attribute behavior.  In general, an
+# object in this hierarchy has three categories of attribute-like
+# things:
+#
+# 1. Regular Python methods and variables.  These must start with an
+# underscore to be treated normally.
+#
+# 2. SimObject parameters.  These values are stored as normal Python
+# attributes, but all assignments to these attributes are checked
+# against the pre-defined set of parameters stored in the class's
+# _param_dict dictionary.  Assignments to attributes that do not
+# correspond to predefined parameters, or that are not of the correct
+# type, incur runtime errors.
+#
+# 3. Hierarchy children.  The child nodes of a ConfigNode are stored
+# in the node's _children dictionary, but can be accessed using the
+# Python attribute dot-notation (just as they are printed out by the
+# simulator).  Children cannot be created using attribute assigment;
+# they must be added by specifying the parent node in the child's
+# constructor or using the '+=' operator.
+
+# The SimObject parameters are the most complex, for a few reasons.
+# First, both parameter descriptions and parameter values are
+# inherited.  Thus parameter description lookup must go up the
+# inheritance chain like normal attribute lookup, but this behavior
+# must be explicitly coded since the lookup occurs in each class's
+# _param_dict attribute.  Second, because parameter values can be set
+# on SimObject classes (to implement default values), the parameter
+# checking behavior must be enforced on class attribute assignments as
+# well as instance attribute assignments.  Finally, because we allow
+# class specialization via inheritance (e.g., see the L1Cache class in
+# the simple-4cpu.py example), we must do parameter checking even on
+# class instantiation.  To provide all these features, we use a
+# metaclass to define most of the SimObject parameter behavior for
+# this class hierarchy.
+#
+#####################################################################
+
+# The metaclass for ConfigNode (and thus for everything that derives
+# from ConfigNode, including SimObject).  This class controls how new
+# classes that derive from ConfigNode are instantiated, and provides
+# inherited class behavior (just like a class controls how instances
+# of that class are instantiated, and provides inherited instance
+# behavior).
+class MetaConfigNode(type):
+
+    # __new__ is called before __init__, and is where the statements
+    # in the body of the class definition get loaded into the class's
+    # __dict__.  We intercept this to filter out parameter assignments
+    # and only allow "private" attributes to be passed to the base
+    # __new__ (starting with underscore).
+    def __new__(cls, name, bases, dict):
+        priv_keys = [k for k in dict.iterkeys() if k.startswith('_')]
+        priv_dict = {}
+        for k in priv_keys: priv_dict[k] = dict[k]; del dict[k]
+        # entries left in dict will get passed to __init__, where we'll
+        # deal with them as params.
+        return super(MetaConfigNode, cls).__new__(cls, name, bases, priv_dict)
+
+    # initialization: start out with an empty param dict (makes life
+    # simpler if we can assume _param_dict is always valid).  Also
+    # build inheritance list to simplify searching for inherited
+    # params.  Finally set parameters specified in class definition
+    # (if any).
+    def __init__(cls, name, bases, dict):
+        super(MetaConfigNode, cls).__init__(cls, name, bases, {})
+        # initialize _param_dict to empty
+        cls._param_dict = {}
+        # __mro__ is the ordered list of classes Python uses for
+        # method resolution.  We want to pick out the ones that have a
+        # _param_dict attribute for doing parameter lookups.
+        cls._param_bases = \
+                         [c for c in cls.__mro__ if hasattr(c, '_param_dict')]
+        # initialize attributes with values from class definition
+        for (pname, value) in dict.items():
+            try:
+                setattr(cls, pname, value)
+            except Exception, exc:
+                print "Error setting '%s' to '%s' on class '%s'\n" \
+                      % (pname, value, cls.__name__), exc
+
+    # set the class's parameter dictionary (called when loading
+    # class descriptions)
+    def set_param_dict(cls, param_dict):
+        # should only be called once (current one should be empty one
+        # from __init__)
+        assert not cls._param_dict
+        cls._param_dict = param_dict
+        # initialize attributes with default values
+        for (pname, param) in param_dict.items():
+            try:
+                setattr(cls, pname, param.default)
+            except Exception, exc:
+                print "Error setting '%s' default on class '%s'\n" \
+                      % (pname, cls.__name__), exc
+
+    # Set the class's parameter dictionary given a code string of
+    # parameter initializers (as from an object description file).
+    # Note that the caller must pass in the namespace in which to
+    # execute the code (usually the caller's globals()), since if we
+    # call globals() from inside this function all we get is this
+    # module's internal scope.
+    def init_params(cls, init_code, ctx):
+        dict = {}
+        try:
+            exec fixPythonIndentation(init_code) in ctx, dict
+        except Exception, exc:
+            print "Error in %s.init_params:" % cls.__name__, exc
+            raise
+        cls.set_param_dict(dict)
+
+    # Lookup a parameter description by name in the given class.  Use
+    # the _param_bases list defined in __init__ to go up the
+    # inheritance hierarchy if necessary.
+    def lookup_param(cls, param_name):
+        for c in cls._param_bases:
+            param = c._param_dict.get(param_name)
+            if param: return param
+        return None
+
+    # Set attribute (called on foo.attr_name = value when foo is an
+    # instance of class cls).
+    def __setattr__(cls, attr_name, value):
+        # normal processing for private attributes
+        if attr_name.startswith('_'):
+            type.__setattr__(cls, attr_name, value)
+            return
+        # no '_': must be SimObject param
+        param = cls.lookup_param(attr_name)
+        if not param:
+            raise AttributeError, \
+                  "Class %s has no parameter %s" % (cls.__name__, attr_name)
+        # It's ok: set attribute by delegating to 'object' class.
+        # Note the use of param.make_value() to verify/canonicalize
+        # the assigned value
+        type.__setattr__(cls, attr_name, param.make_value(value))
+
+    # generator that iterates across all parameters for this class and
+    # all classes it inherits from
+    def all_param_names(cls):
+        for c in cls._param_bases:
+            for p in c._param_dict.iterkeys():
+                yield p
+
+# The ConfigNode class is the root of the special hierarchy.  Most of
+# the code in this class deals with the configuration hierarchy itself
+# (parent/child node relationships).
+class ConfigNode(object):
+    # Specify metaclass.  Any class inheriting from ConfigNode will
+    # get this metaclass.
+    __metaclass__ = MetaConfigNode
+
+    # Constructor.  Since bare ConfigNodes don't have parameters, just
+    # worry about the name and the parent/child stuff.
+    def __init__(self, _name, _parent=None):
+        # Type-check _name
+        if type(_name) != str:
+            if isinstance(_name, ConfigNode):
+                # special case message for common error of trying to
+                # coerce a SimObject to the wrong type
+                raise TypeError, \
+                      "Attempt to coerce %s to %s" \
+                      % (_name.__class__.__name__, self.__class__.__name__)
+            else:
+                raise TypeError, \
+                      "%s name must be string (was %s, %s)" \
+                      % (self.__class__.__name__, _name, type(_name))
+        # if specified, parent must be a subclass of ConfigNode
+        if _parent != None and not isinstance(_parent, ConfigNode):
+            raise TypeError, \
+                  "%s parent must be ConfigNode subclass (was %s, %s)" \
+                  % (self.__class__.__name__, _name, type(_name))
+        self._name = _name
+        self._parent = _parent
+        if (_parent):
+            _parent._add_child(self)
+        self._children = {}
+        # keep a list of children in addition to the dictionary keys
+        # so we can remember the order they were added and print them
+        # out in that order.
+        self._child_list = []
+
+    # When printing (e.g. to .ini file), just give the name.
+    def __str__(self):
+        return self._name
+
+    # Catch attribute accesses that could be requesting children, and
+    # satisfy them.  Note that __getattr__ is called only if the
+    # regular attribute lookup fails, so private and parameter lookups
+    # will already be satisfied before we ever get here.
+    def __getattr__(self, name):
+        try:
+            return self._children[name]
+        except KeyError:
+            raise AttributeError, \
+                  "Node '%s' has no attribute or child '%s'" \
+                  % (self._name, name)
+
+    # Set attribute.  All attribute assignments go through here.  Must
+    # be private attribute (starts with '_') or valid parameter entry.
+    # Basically identical to MetaConfigClass.__setattr__(), except
+    # this sets attributes on specific instances rather than on classes.
+    def __setattr__(self, attr_name, value):
+        if attr_name.startswith('_'):
+            object.__setattr__(self, attr_name, value)
+            return
+        # not private; look up as param
+        param = self.__class__.lookup_param(attr_name)
+        if not param:
+            raise AttributeError, \
+                  "Class %s has no parameter %s" \
+                  % (self.__class__.__name__, attr_name)
+        # It's ok: set attribute by delegating to 'object' class.
+        # Note the use of param.make_value() to verify/canonicalize
+        # the assigned value.
+        v = param.make_value(value)
+        object.__setattr__(self, attr_name, v)
+
+        # A little convenient magic: if the parameter is a ConfigNode
+        # (or vector of ConfigNodes, or anything else with a
+        # '_set_parent_if_none' function attribute) that does not have
+        # a parent (and so is not part of the configuration
+        # hierarchy), then make this node its parent.
+        if hasattr(v, '_set_parent_if_none'):
+            v._set_parent_if_none(self)
+
+    def _path(self):
+        # Return absolute path from root.
+        if not self._parent and self._name != 'Universe':
+            print >> sys.stderr, "Warning:", self._name, "has no parent"
+        parent_path = self._parent and self._parent._path()
+        if parent_path and parent_path != 'Universe':
+            return parent_path + '.' + self._name
+        else:
+            return self._name
+
+    # Add a child to this node.
+    def _add_child(self, new_child):
+        # set child's parent before calling this function
+        assert new_child._parent == self
+        if not isinstance(new_child, ConfigNode):
+            raise TypeError, \
+                  "ConfigNode child must also be of class ConfigNode"
+        if new_child._name in self._children:
+            raise AttributeError, \
+                  "Node '%s' already has a child '%s'" \
+                  % (self._name, new_child._name)
+        self._children[new_child._name] = new_child
+        self._child_list += [new_child]
+
+    # operator overload for '+='.  You can say "node += child" to add
+    # a child that was created with parent=None.  An early attempt
+    # at playing with syntax; turns out not to be that useful.
+    def __iadd__(self, new_child):
+        if new_child._parent != None:
+            raise AttributeError, \
+                  "Node '%s' already has a parent" % new_child._name
+        new_child._parent = self
+        self._add_child(new_child)
+        return self
+
+    # Set this instance's parent to 'parent' if it doesn't already
+    # have one.  See ConfigNode.__setattr__().
+    def _set_parent_if_none(self, parent):
+        if self._parent == None:
+            parent += self
+
+    # Print instance info to .ini file.
+    def _instantiate(self):
+        print '[' + self._path() + ']'	# .ini section header
+        if self._child_list:
+            # instantiate children in same order they were added for
+            # backward compatibility (else we can end up with cpu1
+            # before cpu0).
+            print 'children =', ' '.join([c._name for c in self._child_list])
+        self._instantiateParams()
+        print
+        # recursively dump out children
+        for c in self._child_list:
+            c._instantiate()
+
+    # ConfigNodes have no parameters.  Overridden by SimObject.
+    def _instantiateParams(self):
+        pass
+
+# SimObject is a minimal extension of ConfigNode, implementing a
+# hierarchy node that corresponds to an M5 SimObject.  It prints out a
+# "type=" line to indicate its SimObject class, prints out the
+# assigned parameters corresponding to its class, and allows
+# parameters to be set by keyword in the constructor.  Note that most
+# of the heavy lifting for the SimObject param handling is done in the
+# MetaConfigNode metaclass.
+
+class SimObject(ConfigNode):
+    # initialization: like ConfigNode, but handle keyword-based
+    # parameter initializers.
+    def __init__(self, _name, _parent=None, **params):
+        ConfigNode.__init__(self, _name, _parent)
+        for param, value in params.items():
+            setattr(self, param, value)
+
+    # print type and parameter values to .ini file
+    def _instantiateParams(self):
+        print "type =", self.__class__._name
+        for pname in self.__class__.all_param_names():
+            value = getattr(self, pname)
+            if value != None:
+                print pname, '=', value
+
+    def _sim_code(cls):
+        name = cls.__name__
+        param_names = cls._param_dict.keys()
+        param_names.sort()
+        code = "BEGIN_DECLARE_SIM_OBJECT_PARAMS(%s)\n" % name
+        decls = ["  " + cls._param_dict[pname].sim_decl(pname) \
+                 for pname in param_names]
+        code += "\n".join(decls) + "\n"
+        code += "END_DECLARE_SIM_OBJECT_PARAMS(%s)\n\n" % name
+        code += "BEGIN_INIT_SIM_OBJECT_PARAMS(%s)\n" % name
+        inits = ["  " + cls._param_dict[pname].sim_init(pname) \
+                 for pname in param_names]
+        code += ",\n".join(inits) + "\n"
+        code += "END_INIT_SIM_OBJECT_PARAMS(%s)\n\n" % name
+        return code
+    _sim_code = classmethod(_sim_code)
+
+#####################################################################
+#
+# Parameter description classes
+#
+# The _param_dict dictionary in each class maps parameter names to
+# either a Param or a VectorParam object.  These objects contain the
+# parameter description string, the parameter type, and the default
+# value (loaded from the PARAM section of the .odesc files).  The
+# make_value() method on these objects is used to force whatever value
+# is assigned to the parameter to the appropriate type.
+#
+# Note that the default values are loaded into the class's attribute
+# space when the parameter dictionary is initialized (in
+# MetaConfigNode.set_param_dict()); after that point they aren't
+# used.
+#
+#####################################################################
+
+def isNullPointer(value):
+    return isinstance(value, NullSimObject)
+
+# Regular parameter.
+class Param(object):
+    # Constructor.  E.g., Param(Int, "number of widgets", 5)
+    def __init__(self, ptype, desc, default=None):
+        self.ptype = ptype
+        self.ptype_name = self.ptype.__name__
+        self.desc = desc
+        self.default = default
+
+    # Convert assigned value to appropriate type.  Force parameter
+    # value (rhs of '=') to ptype (or None, which means not set).
+    def make_value(self, value):
+        # nothing to do if None or already correct type.  Also allow NULL
+        # pointer to be assigned where a SimObject is expected.
+        if value == None or isinstance(value, self.ptype) or \
+               isNullPointer(value) and issubclass(self.ptype, ConfigNode):
+            return value
+        # this type conversion will raise an exception if it's illegal
+        return self.ptype(value)
+
+    def sim_decl(self, name):
+        return 'Param<%s> %s;' % (self.ptype_name, name)
+
+    def sim_init(self, name):
+        if self.default == None:
+            return 'INIT_PARAM(%s, "%s")' % (name, self.desc)
+        else:
+            return 'INIT_PARAM_DFLT(%s, "%s", %s)' % \
+                   (name, self.desc, str(self.default))
+
+# The _VectorParamValue class is a wrapper for vector-valued
+# parameters.  The leading underscore indicates that users shouldn't
+# see this class; it's magically generated by VectorParam.  The
+# parameter values are stored in the 'value' field as a Python list of
+# whatever type the parameter is supposed to be.  The only purpose of
+# storing these instead of a raw Python list is that we can override
+# the __str__() method to not print out '[' and ']' in the .ini file.
+class _VectorParamValue(object):
+    def __init__(self, value):
+        assert isinstance(value, list) or value == None
+        self.value = value
+
+    def __str__(self):
+        return ' '.join(map(str, self.value))
+
+    # Set member instance's parents to 'parent' if they don't already
+    # have one.  Extends "magic" parenting of ConfigNodes to vectors
+    # of ConfigNodes as well.  See ConfigNode.__setattr__().
+    def _set_parent_if_none(self, parent):
+        if self.value and hasattr(self.value[0], '_set_parent_if_none'):
+            for v in self.value:
+                v._set_parent_if_none(parent)
+
+# Vector-valued parameter description.  Just like Param, except that
+# the value is a vector (list) of the specified type instead of a
+# single value.
+class VectorParam(Param):
+
+    # Inherit Param constructor.  However, the resulting parameter
+    # will be a list of ptype rather than a single element of ptype.
+    def __init__(self, ptype, desc, default=None):
+        Param.__init__(self, ptype, desc, default)
+
+    # Convert assigned value to appropriate type.  If the RHS is not a
+    # list or tuple, it generates a single-element list.
+    def make_value(self, value):
+        if value == None: return value
+        if isinstance(value, list) or isinstance(value, tuple):
+            # list: coerce each element into new list
+            val_list = [Param.make_value(self, v) for v in iter(value)]
+        else:
+            # singleton: coerce & wrap in a list
+            val_list = [Param.make_value(self, value)]
+        # wrap list in _VectorParamValue (see above)
+        return _VectorParamValue(val_list)
+
+    def sim_decl(self, name):
+        return 'VectorParam<%s> %s;' % (self.ptype_name, name)
+
+    # sim_init inherited from Param
+
+#####################################################################
+#
+# Parameter Types
+#
+# Though native Python types could be used to specify parameter types
+# (the 'ptype' field of the Param and VectorParam classes), it's more
+# flexible to define our own set of types.  This gives us more control
+# over how Python expressions are converted to values (via the
+# __init__() constructor) and how these values are printed out (via
+# the __str__() conversion method).  Eventually we'll need these types
+# to correspond to distinct C++ types as well.
+#
+#####################################################################
+
+# Integer parameter type.
+class Int(object):
+    # Constructor.  Value must be Python int or long (long integer).
+    def __init__(self, value):
+        t = type(value)
+        if t == int or t == long:
+            self.value = value
+        else:
+            raise TypeError, "Int param got value %s %s" % (repr(value), t)
+
+    # Use Python string conversion.  Note that this puts an 'L' on the
+    # end of long integers; we can strip that off here if it gives us
+    # trouble.
+    def __str__(self):
+        return str(self.value)
+
+# Counter, Addr, and Tick are just aliases for Int for now.
+class Counter(Int):
+    pass
+
+class Addr(Int):
+    pass
+
+class Tick(Int):
+    pass
+
+# Boolean parameter type.
+class Bool(object):
+
+    # Constructor.  Typically the value will be one of the Python bool
+    # constants True or False (or the aliases true and false below).
+    # Also need to take integer 0 or 1 values since bool was not a
+    # distinct type in Python 2.2.  Parse a bunch of boolean-sounding
+    # strings too just for kicks.
+    def __init__(self, value):
+        t = type(value)
+        if t == bool:
+            self.value = value
+        elif t == int or t == long:
+            if value == 1:
+                self.value = True
+            elif value == 0:
+                self.value = False
+        elif t == str:
+            v = value.lower()
+            if v == "true" or v == "t" or v == "yes" or v == "y":
+                self.value = True
+            elif v == "false" or v == "f" or v == "no" or v == "n":
+                self.value = False
+        # if we didn't set it yet, it must not be something we understand
+        if not hasattr(self, 'value'):
+            raise TypeError, "Bool param got value %s %s" % (repr(value), t)
+
+    # Generate printable string version.
+    def __str__(self):
+        if self.value: return "true"
+        else: return "false"
+
+# String-valued parameter.
+class String(object):
+    # Constructor.  Value must be Python string.
+    def __init__(self, value):
+        t = type(value)
+        if t == str:
+            self.value = value
+        else:
+            raise TypeError, "String param got value %s %s" % (repr(value), t)
+
+    # Generate printable string version.  Not too tricky.
+    def __str__(self):
+        return self.value
+
+# Special class for NULL pointers.  Note the special check in
+# make_param_value() above that lets these be assigned where a
+# SimObject is required.
+class NullSimObject(object):
+    # Constructor.  No parameters, nothing to do.
+    def __init__(self):
+        pass
+
+    def __str__(self):
+        return "NULL"
+
+# The only instance you'll ever need...
+NULL = NullSimObject()
+
+# Enumerated types are a little more complex.  The user specifies the
+# type as Enum(foo) where foo is either a list or dictionary of
+# alternatives (typically strings, but not necessarily so).  (In the
+# long run, the integer value of the parameter will be the list index
+# or the corresponding dictionary value.  For now, since we only check
+# that the alternative is valid and then spit it into a .ini file,
+# there's not much point in using the dictionary.)
+
+# What Enum() must do is generate a new type encapsulating the
+# provided list/dictionary so that specific values of the parameter
+# can be instances of that type.  We define two hidden internal
+# classes (_ListEnum and _DictEnum) to serve as base classes, then
+# derive the new type from the appropriate base class on the fly.
+
+
+# Base class for list-based Enum types.
+class _ListEnum(object):
+    # Constructor.  Value must be a member of the type's map list.
+    def __init__(self, value):
+        if value in self.map:
+            self.value = value
+            self.index = self.map.index(value)
+        else:
+            raise TypeError, "Enum param got bad value '%s' (not in %s)" \
+                  % (value, self.map)
+
+    # Generate printable string version of value.
+    def __str__(self):
+        return str(self.value)
+
+class _DictEnum(object):
+    # Constructor.  Value must be a key in the type's map dictionary.
+    def __init__(self, value):
+        if value in self.map:
+            self.value = value
+            self.index = self.map[value]
+        else:
+            raise TypeError, "Enum param got bad value '%s' (not in %s)" \
+                  % (value, self.map.keys())
+
+    # Generate printable string version of value.
+    def __str__(self):
+        return str(self.value)
+
+# Enum metaclass... calling Enum(foo) generates a new type (class)
+# that derives from _ListEnum or _DictEnum as appropriate.
+class Enum(type):
+    # counter to generate unique names for generated classes
+    counter = 1
+
+    def __new__(cls, map):
+        if isinstance(map, dict):
+            base = _DictEnum
+            keys = map.keys()
+        elif isinstance(map, list):
+            base = _ListEnum
+            keys = map
+        else:
+            raise TypeError, "Enum map must be list or dict (got %s)" % map
+        classname = "Enum%04d" % Enum.counter
+        Enum.counter += 1
+        # New class derives from selected base, and gets a 'map'
+        # attribute containing the specified list or dict.
+        return type.__new__(cls, classname, (base,), { 'map': map })
+
+
+#
+# "Constants"... handy aliases for various values.
+#
+
+# For compatibility with C++ bool constants.
+false = False
+true = True
+
+# Some memory range specifications use this as a default upper bound.
+MAX_ADDR = 2**64 - 1
+
+# For power-of-two sizing, e.g. 64*K gives an integer value 65536.
+K = 1024
+M = K*K
+G = K*M
+
+#####################################################################
+
+# Munge an arbitrary Python code string to get it to execute (mostly
+# dealing with indentation).  Stolen from isa_parser.py... see
+# comments there for a more detailed description.
+def fixPythonIndentation(s):
+    # get rid of blank lines first
+    s = re.sub(r'(?m)^\s*\n', '', s);
+    if (s != '' and re.match(r'[ \t]', s[0])):
+        s = 'if 1:\n' + s
+    return s
+
+# Hook to generate C++ parameter code.
+def gen_sim_code(file):
+    for objname in sim_object_list:
+        print >> file, eval("%s._sim_code()" % objname)
+
+# The final hook to generate .ini files.  Called from configuration
+# script once config is built.
+def instantiate(*objs):
+    for obj in objs:
+        obj._instantiate()
+
+