libm5: Create a libm5 static library for embedding m5.

This should allow m5 to be more easily embedded into other simulators.
The m5 binary adds a simple main function which then calls into the m5
libarary to start the simulation. In order to make this work
correctly, it was necessary embed python code directly into the
library instead of the zipfile hack.  This is because you can't just
append the zipfile to the end of a library the way you can a binary.
As a result, Python files that are part of the m5 simulator are now
compile, marshalled, compressed, and then inserted into the library's
data section with a certain symbol name.  Additionally, a new Importer
was needed to allow python to get at the embedded python code.

Small additional changes include:
- Get rid of the PYTHONHOME stuff since I don't think anyone ever used
it, and it just confuses things.  Easy enough to add back if I'm wrong.
- Create a few new functions that are key to initializing and running
the simulator: initSignals, initM5Python, m5Main.

The original code for creating libm5 was inspired by a patch Michael
Adler, though the code here was done by me.

9 files changed, 491 insertions, 172 deletions

diff --git a/SConstruct b/SConstruct
index 792cb7554..f7798b25e 100644
--- a/SConstruct
+++ b/SConstruct
@@ -424,11 +424,42 @@ scanners.append(CPPScanner("SwigScan", [ ".i" ], "CPPPATH", swig_inc_re))
 # replace the scanners list that has what we want
 env['SCANNERS'] = scanners
 
+# Add a custom Check function to the Configure context so that we can
+# figure out if the compiler adds leading underscores to global
+# variables.  This is needed for the autogenerated asm files that we
+# use for embedding the python code.
+def CheckLeading(context):
+    context.Message("Checking for leading underscore in global variables...")
+    # 1) Define a global variable called x from asm so the C compiler
+    #    won't change the symbol at all.
+    # 2) Declare that variable.
+    # 3) Use the variable
+    #
+    # If the compiler prepends an underscore, this will successfully
+    # link because the external symbol 'x' will be called '_x' which
+    # was defined by the asm statement.  If the compiler does not
+    # prepend an underscore, this will not successfully link because
+    # '_x' will have been defined by assembly, while the C portion of
+    # the code will be trying to use 'x'
+    ret = context.TryLink('''
+        asm(".globl _x; _x: .byte 0");
+        extern int x;
+        int main() { return x; }
+        ''', extension=".c")
+    context.env.Append(LEADING_UNDERSCORE=ret)
+    context.Result(ret)
+    return ret
+
 # Platform-specific configuration.  Note again that we assume that all
 # builds under a given build root run on the same host platform.
 conf = Configure(env,
                  conf_dir = joinpath(build_root, '.scons_config'),
-                 log_file = joinpath(build_root, 'scons_config.log'))
+                 log_file = joinpath(build_root, 'scons_config.log'),
+                 custom_tests = { 'CheckLeading' : CheckLeading })
+
+# Check for leading underscores.  Don't really need to worry either
+# way so don't need to check the return code.
+conf.CheckLeading()
 
 # Check if we should compile a 64 bit binary on Mac OS X/Darwin
 try:
@@ -596,9 +627,6 @@ sticky_opts.AddOptions(
     BoolOption('USE_MYSQL', 'Use MySQL for stats output', have_mysql),
     BoolOption('USE_FENV', 'Use <fenv.h> IEEE mode control', have_fenv),
     BoolOption('USE_CHECKER', 'Use checker for detailed CPU models', False),
-    ('PYTHONHOME',
-     'Override the default PYTHONHOME for this system (use with caution)',
-     '%s:%s' % (sys.prefix, sys.exec_prefix)),
     )
 
 nonsticky_opts.AddOptions(
@@ -609,7 +637,7 @@ nonsticky_opts.AddOptions(
 env.ExportOptions = ['FULL_SYSTEM', 'ALPHA_TLASER', 'USE_FENV', \
                      'USE_MYSQL', 'NO_FAST_ALLOC', 'FAST_ALLOC_DEBUG', \
                      'FAST_ALLOC_STATS', 'SS_COMPATIBLE_FP', \
-                     'USE_CHECKER', 'PYTHONHOME', 'TARGET_ISA']
+                     'USE_CHECKER', 'TARGET_ISA']
 
 # Define a handy 'no-op' action
 def no_action(target, source, env):
diff --git a/src/SConscript b/src/SConscript
index ad1fe76a9..36cbbfa78 100644
--- a/src/SConscript
+++ b/src/SConscript
@@ -28,11 +28,13 @@
 #
 # Authors: Nathan Binkert
 
+import array
 import imp
+import marshal
 import os
-import py_compile
+import re
 import sys
-import zipfile
+import zlib
 
 from os.path import basename, exists, isdir, isfile, join as joinpath
 
@@ -58,39 +60,54 @@ def sort_list(_list):
     return _list
 
 class PySourceFile(object):
+    invalid_sym_char = re.compile('[^A-z0-9_]')
     def __init__(self, package, source):
         filename = str(source)
         pyname = basename(filename)
         assert pyname.endswith('.py')
         name = pyname[:-3]
-        path = package.split('.')
+        if package:
+            path = package.split('.')
+        else:
+            path = []
         modpath = path
         if name != '__init__':
             modpath += [name]
         modpath = '.'.join(modpath)
 
-        arcpath = package.split('.') + [ pyname + 'c' ]
+        arcpath = path + [ pyname ]
         arcname = joinpath(*arcpath)
 
-        self.source = source
+        self.tnode = source
+        self.snode = source.srcnode()
         self.pyname = pyname
-        self.srcpath = source.srcnode().abspath
         self.package = package
         self.modpath = modpath
         self.arcname = arcname
         self.filename = filename
         self.compiled = File(filename + 'c')
+        self.assembly = File(filename + '.s')
+        self.symname = "PyEMB_" + self.invalid_sym_char.sub('_', modpath)
+        
 
 ########################################################################
 # Code for adding source files of various types
 #
-cc_sources = []
+cc_lib_sources = []
 def Source(source):
-    '''Add a C/C++ source file to the build'''
+    '''Add a source file to the libm5 build'''
+    if not isinstance(source, SCons.Node.FS.File):
+        source = File(source)
+
+    cc_lib_sources.append(source)
+
+cc_bin_sources = []
+def BinSource(source):
+    '''Add a source file to the m5 binary build'''
     if not isinstance(source, SCons.Node.FS.File):
         source = File(source)
 
-    cc_sources.append(source)
+    cc_bin_sources.append(source)
 
 py_sources = []
 def PySource(package, source):
@@ -129,6 +146,7 @@ def SwigSource(package, source):
 
 # Children should have access
 Export('Source')
+Export('BinSource')
 Export('PySource')
 Export('SimObject')
 Export('SwigSource')
@@ -259,7 +277,7 @@ class DictImporter(object):
 
 py_modules = {}
 for source in py_sources:
-    py_modules[source.modpath] = source.srcpath
+    py_modules[source.modpath] = source.snode.abspath
 
 # install the python importer so we can grab stuff from the source
 # tree itself.  We can't have SimObjects added after this point or
@@ -551,14 +569,14 @@ def makeSwigInit(target, source, env):
     for module in source:
         print >>f, '    void init_%s();' % module.get_contents()
     print >>f, '}'
-    print >>f, 'void init_swig() {'
+    print >>f, 'void initSwig() {'
     for module in source:
         print >>f, '    init_%s();' % module.get_contents()
     print >>f, '}'
     f.close()
 
-env.Command('swig/init.cc', swig_modules, makeSwigInit)
-Source('swig/init.cc')
+env.Command('python/swig/init.cc', swig_modules, makeSwigInit)
+Source('python/swig/init.cc')
 
 # Generate traceflags.py
 def traceFlagsPy(target, source, env):
@@ -797,42 +815,95 @@ env.Command('base/program_info.cc',
             Value(str(SCons.Node.FS.default_fs.SConstruct_dir)),
             programInfo)
 
-# Build the zip file
-def compilePyFile(target, source, env):
-    '''Action function to compile a .py into a .pyc'''
-    py_compile.compile(str(source[0]), str(target[0]))
-
-def buildPyZip(target, source, env):
-    '''Action function to build the zip archive.  Uses the
-    PyZipFile module included in the standard Python library.'''
-
-    py_compiled = {}
-    for s in py_sources:
-        compname = str(s.compiled)
-        assert compname not in py_compiled
-        py_compiled[compname] = s
-
-    zf = zipfile.ZipFile(str(target[0]), 'w')
-    for s in source:
-        zipname = str(s)
-        arcname = py_compiled[zipname].arcname
-        zf.write(zipname, arcname)
-    zf.close()
+# embed python files.  All .py files that have been indicated by a
+# PySource() call in a SConscript need to be embedded into the M5
+# library.  To do that, we compile the file to byte code, marshal the
+# byte code, compress it, and then generate an assembly file that
+# inserts the result into the data section with symbols indicating the
+# beginning, and end (and with the size at the end)
+py_sources_tnodes = {}
+for pysource in py_sources:
+    py_sources_tnodes[pysource.tnode] = pysource
+
+def objectifyPyFile(target, source, env):
+    '''Action function to compile a .py into a code object, marshal
+    it, compress it, and stick it into an asm file so the code appears
+    as just bytes with a label in the data section'''
+
+    src = file(str(source[0]), 'r').read()
+    dst = file(str(target[0]), 'w')
+
+    pysource = py_sources_tnodes[source[0]]
+    compiled = compile(src, pysource.snode.path, 'exec')
+    marshalled = marshal.dumps(compiled)
+    compressed = zlib.compress(marshalled)
+    data = compressed
+
+    # Some C/C++ compilers prepend an underscore to global symbol
+    # names, so if they're going to do that, we need to prepend that
+    # leading underscore to globals in the assembly file.
+    if env['LEADING_UNDERSCORE']:
+        sym = '_' + pysource.symname
+    else:
+        sym = pysource.symname
+
+    step = 16
+    print >>dst, ".data"
+    print >>dst, ".globl %s_beg" % sym
+    print >>dst, ".globl %s_end" % sym
+    print >>dst, "%s_beg:" % sym
+    for i in xrange(0, len(data), step):
+        x = array.array('B', data[i:i+step])
+        print >>dst, ".byte", ','.join([str(d) for d in x])
+    print >>dst, "%s_end:" % sym
+    print >>dst, ".long %d" % len(marshalled)
 
-py_compiled = []
-py_zip_depends = []
 for source in py_sources:
-    env.Command(source.compiled, source.source, compilePyFile)
-    py_compiled.append(source.compiled)
-
-    # make the zipfile depend on the archive name so that the archive
-    # is rebuilt if the name changes
-    py_zip_depends.append(Value(source.arcname))
+    env.Command(source.assembly, source.tnode, objectifyPyFile)
+    Source(source.assembly)
+
+# Generate init_python.cc which creates a bunch of EmbeddedPyModule
+# structs that describe the embedded python code.  One such struct
+# contains information about the importer that python uses to get at
+# the embedded files, and then there's a list of all of the rest that
+# the importer uses to load the rest on demand.
+py_sources_symbols = {}
+for pysource in py_sources:
+    py_sources_symbols[pysource.symname] = pysource
+def pythonInit(target, source, env):
+    dst = file(str(target[0]), 'w')
+
+    def dump_mod(sym, endchar=','):
+        pysource = py_sources_symbols[sym]
+        print >>dst, '    { "%s",' % pysource.arcname
+        print >>dst, '      "%s",' % pysource.modpath
+        print >>dst, '       %s_beg, %s_end,' % (sym, sym)
+        print >>dst, '       %s_end - %s_beg,' % (sym, sym)
+        print >>dst, '       *(int *)%s_end }%s'  % (sym, endchar)
+    
+    print >>dst, '#include "sim/init.hh"'
+
+    for sym in source:
+        sym = sym.get_contents()
+        print >>dst, "extern const char %s_beg[], %s_end[];" % (sym, sym)
+
+    print >>dst, "const EmbeddedPyModule embeddedPyImporter = "
+    dump_mod("PyEMB_importer", endchar=';');
+    print >>dst
+
+    print >>dst, "const EmbeddedPyModule embeddedPyModules[] = {"
+    for i,sym in enumerate(source):
+        sym = sym.get_contents()
+        if sym == "PyEMB_importer":
+            # Skip the importer since we've already exported it
+            continue
+        dump_mod(sym)
+    print >>dst, "    { 0, 0, 0, 0, 0, 0 }"
+    print >>dst, "};"
 
-# Add the zip file target to the environment.
-m5zip = File('m5py.zip')
-env.Command(m5zip, py_compiled, buildPyZip)
-env.Depends(m5zip, py_zip_depends)
+symbols = [Value(s.symname) for s in py_sources]
+env.Command('sim/init_python.cc', symbols, pythonInit)
+Source('sim/init_python.cc')
 
 ########################################################################
 #
@@ -873,18 +944,28 @@ def makeEnv(label, objsfx, strip = False, **kwargs):
     newEnv = env.Copy(OBJSUFFIX=objsfx)
     newEnv.Label = label
     newEnv.Append(**kwargs)
+
+    # First make a library of everything but main() so other programs can
+    # link against m5.
+    #
+    # SCons doesn't know to append a library suffix when there is a '.' in the
+    # name.  Use '_' instead.
+    m5lib = newEnv.Library('m5_' + label, make_objs(cc_lib_sources, newEnv))
+
+    # Now link a stub with main() and the library.
     exe = 'm5.' + label  # final executable
-    bin = exe + '.bin'   # executable w/o appended Python zip archive
-    newEnv.Program(bin, make_objs(cc_sources, newEnv))
+    objects = [newEnv.Object(s) for s in cc_bin_sources] + m5lib
     if strip:
-        stripped_bin = bin + '.stripped'
+        unstripped_exe = exe + '.unstripped'
+        newEnv.Program(unstripped_exe, objects)
         if sys.platform == 'sunos5':
             cmd = 'cp $SOURCE $TARGET; strip $TARGET'
         else:
             cmd = 'strip $SOURCE -o $TARGET'
-        newEnv.Command(stripped_bin, bin, cmd)
-        bin = stripped_bin
-    targets = newEnv.Concat(exe, [bin, 'm5py.zip'])
+        targets = newEnv.Command(exe, unstripped_exe, cmd)
+    else:
+        targets = newEnv.Program(exe, objects)
+            
     newEnv.M5Binary = targets[0]
     envList.append(newEnv)
 
diff --git a/src/python/SConscript b/src/python/SConscript
index 32bab4526..94119c77d 100644
--- a/src/python/SConscript
+++ b/src/python/SConscript
@@ -34,6 +34,7 @@ Import('*')
 Source('swig/pyevent.cc')
 Source('swig/pyobject.cc')
 
+PySource('', 'importer.py')
 PySource('m5', 'm5/__init__.py')
 PySource('m5', 'm5/SimObject.py')
 PySource('m5', 'm5/config.py')
diff --git a/src/python/importer.py b/src/python/importer.py
new file mode 100644
index 000000000..fe099fdb8
--- /dev/null
+++ b/src/python/importer.py
@@ -0,0 +1,80 @@
+# Copyright (c) 2008 The Hewlett-Packard Development Company
+# 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.
+#
+# Authors: Nathan Binkert
+
+# 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.
+class CodeImporter(object):
+    def __init__(self):
+        self.modules = {}
+
+    def add_module(self, filename, modpath, code):
+        if modpath in self.modules:
+            raise AttributeError, "%s already found in importer"
+
+        self.modules[modpath] = (filename, code)
+
+    def find_module(self, fullname, path):
+        if fullname in self.modules:
+            return self
+
+        return None
+
+    def load_module(self, fullname):
+        # Because the importer is created and initialized in its own
+        # little sandbox (in init.cc), the globals that were available
+        # when the importer module was loaded and CodeImporter was
+        # defined are not available when load_module is actually
+        # called. Soooo, the imports must live here.
+        import imp
+        import os
+        import sys
+        mod = imp.new_module(fullname)
+        sys.modules[fullname] = mod
+
+        try:
+            mod.__loader__ = self
+            srcfile,code = self.modules[fullname]
+            if os.path.basename(srcfile) == '__init__.py':
+                mod.__path__ = fullname.split('.')
+            mod.__file__ = srcfile
+
+            exec code in mod.__dict__
+        except Exception:
+            del sys.modules[fullname]
+            raise
+
+        return mod
+
+# Create an importer and add it to the meta_path so future imports can
+# use it.  There's currently nothing in the importer, but calls to
+# add_module can be used to add code.
+import sys
+importer = CodeImporter()
+add_module = importer.add_module
+sys.meta_path.append(importer)
diff --git a/src/python/m5/__init__.py b/src/python/m5/__init__.py
index f21bb362e..7b071bccd 100644
--- a/src/python/m5/__init__.py
+++ b/src/python/m5/__init__.py
@@ -91,7 +91,7 @@ else:
 if running_m5:
     from event import *
     from simulate import *
-    from main import options
+    from main import options, main
     import stats
 
 import SimObject
diff --git a/src/sim/SConscript b/src/sim/SConscript
index c9e4415f5..3e6adb85a 100644
--- a/src/sim/SConscript
+++ b/src/sim/SConscript
@@ -40,7 +40,8 @@ Source('core.cc')
 Source('debug.cc')
 Source('eventq.cc')
 Source('faults.cc')
-Source('main.cc')
+Source('init.cc')
+BinSource('main.cc')
 Source('root.cc')
 Source('serialize.cc')
 Source('sim_events.cc')
diff --git a/src/sim/init.cc b/src/sim/init.cc
new file mode 100644
index 000000000..804389dae
--- /dev/null
+++ b/src/sim/init.cc
@@ -0,0 +1,202 @@
+/*
+ * Copyright (c) 2000-2005 The Regents of The University of Michigan
+ * Copyright (c) 2008 The Hewlett-Packard Development Company
+ * 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.
+ *
+ * Authors: Nathan Binkert
+ */
+
+#include <Python.h>
+#include <marshal.h>
+#include <signal.h>
+
+#include <iostream>
+#include <string>
+#include <zlib.h>
+
+#include "base/cprintf.hh"
+#include "base/misc.hh"
+#include "sim/async.hh"
+#include "sim/core.hh"
+#include "sim/host.hh"
+#include "sim/init.hh"
+
+using namespace std;
+
+/// Stats signal handler.
+void
+dumpStatsHandler(int sigtype)
+{
+    async_event = true;
+    async_statdump = true;
+}
+
+void
+dumprstStatsHandler(int sigtype)
+{
+    async_event = true;
+    async_statdump = true;
+    async_statreset = true;
+}
+
+/// Exit signal handler.
+void
+exitNowHandler(int sigtype)
+{
+    async_event = true;
+    async_exit = true;
+}
+
+/// Abort signal handler.
+void
+abortHandler(int sigtype)
+{
+    ccprintf(cerr, "Program aborted at cycle %d\n", curTick);
+}
+
+/*
+ * M5 can do several special things when various signals are sent.
+ * None are mandatory.
+ */
+void
+initSignals()
+{
+    // Floating point exceptions may happen on misspeculated paths, so
+    // ignore them
+    signal(SIGFPE, SIG_IGN);
+
+    // We use SIGTRAP sometimes for debugging
+    signal(SIGTRAP, SIG_IGN);
+
+    // Dump intermediate stats
+    signal(SIGUSR1, dumpStatsHandler);
+
+    // Dump intermediate stats and reset them
+    signal(SIGUSR2, dumprstStatsHandler);
+
+    // Exit cleanly on Interrupt (Ctrl-C)
+    signal(SIGINT, exitNowHandler);
+
+    // Print out cycle number on abort
+    signal(SIGABRT, abortHandler);
+}
+
+/*
+ * Uncompress and unmarshal the code object stored in the
+ * EmbeddedPyModule
+ */
+PyObject *
+getCode(const EmbeddedPyModule *pymod)
+{
+    assert(pymod->zlen == pymod->code_end - pymod->code);
+    Bytef *marshalled = new Bytef[pymod->mlen];
+    uLongf unzlen = pymod->mlen;
+    int ret = uncompress(marshalled, &unzlen, (const Bytef *)pymod->code,
+        pymod->zlen);
+    if (ret != Z_OK)
+        panic("Could not uncompress code: %s\n", zError(ret));
+    assert(unzlen == pymod->mlen);
+
+    return PyMarshal_ReadObjectFromString((char *)marshalled, pymod->mlen);
+}
+
+// The python library is totally messed up with respect to constness,
+// so make a simple macro to make life a little easier
+#define PyCC(x) (const_cast<char *>(x))
+
+/*
+ * Load and initialize all of the python parts of M5, including Swig
+ * and the embedded module importer.
+ */
+int
+initM5Python()
+{
+    extern void initSwig();
+
+    // initialize SWIG modules.  initSwig() is autogenerated and calls
+    // all of the individual swig initialization functions.
+    initSwig();
+
+    // Load the importer module
+    PyObject *code = getCode(&embeddedPyImporter);
+    PyObject *module = PyImport_ExecCodeModule(PyCC("importer"), code);
+    if (!module) {
+        PyErr_Print();
+        return 1;
+    }
+
+    // Load the rest of the embedded python files into the embedded
+    // python importer
+    const EmbeddedPyModule *pymod = &embeddedPyModules[0];
+    while (pymod->filename) {
+        PyObject *code = getCode(pymod);
+        PyObject *result = PyObject_CallMethod(module, PyCC("add_module"),
+            PyCC("ssO"), pymod->filename, pymod->modpath, code);
+        if (!result) {
+            PyErr_Print();
+            return 1;
+        }
+        Py_DECREF(result);
+        ++pymod;
+    }
+
+    return 0;
+}
+
+/*
+ * Start up the M5 simulator.  This mostly vectors into the python
+ * main function.
+ */
+int
+m5Main(int argc, char **argv)
+{
+    PySys_SetArgv(argc, argv);
+
+    // We have to set things up in the special __main__ module
+    PyObject *module = PyImport_AddModule(PyCC("__main__"));
+    if (module == NULL)
+        panic("Could not import __main__");
+    PyObject *dict = PyModule_GetDict(module);
+
+    // import the main m5 module
+    PyObject *result;
+    result = PyRun_String("import m5", Py_file_input, dict, dict);
+    if (!result) {
+        PyErr_Print();
+        return 1;
+    }
+    Py_DECREF(result);
+
+    // Start m5
+    result = PyRun_String("m5.main()", Py_file_input, dict, dict);
+    if (!result) {
+        PyErr_Print();
+        return 1;
+    }
+    Py_DECREF(result);
+
+    return 0;
+}
diff --git a/src/python/swig/init.hh b/src/sim/init.hh
index 23d2c19a9..b0f29bf30 100644
--- a/src/python/swig/init.hh
+++ b/src/sim/init.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006 The Regents of The University of Michigan
+ * Copyright (c) 2008 The Hewlett-Packard Development Company
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -28,9 +28,27 @@
  * Authors: Nathan Binkert
  */
 
-#ifndef __PYTHON_SWIG_INIT_HH__
-#define __PYTHON_SWIG_INIT_HH__
+#ifndef __SIM_INIT_HH__
+#define __SIM_INIT_HH__
 
-void init_swig();
+/*
+ * Data structure describing an embedded python file.
+ */
+struct EmbeddedPyModule
+{
+    const char *filename;
+    const char *modpath;
+    const char *code;
+    const char *code_end;
+    int zlen;
+    int mlen;
+};
+
+extern const EmbeddedPyModule embeddedPyImporter;
+extern const EmbeddedPyModule embeddedPyModules[];
+
+void initSignals();
+int initM5Python();
+int m5Main(int argc, char **argv);
 
-#endif // __PYTHON_SWIG_INIT_HH__
+#endif // __SIM_INIT_HH__
diff --git a/src/sim/main.cc b/src/sim/main.cc
index baca556a0..d674e0cff 100644
--- a/src/sim/main.cc
+++ b/src/sim/main.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000-2005 The Regents of The University of Michigan
+ * Copyright (c) 2008 The Hewlett-Packard Development Company
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -29,125 +29,33 @@
  */
 
 #include <Python.h>
-#include <signal.h>
 
-#include <iostream>
-#include <string>
-
-#include "base/cprintf.hh"
-#include "base/misc.hh"
-#include "config/pythonhome.hh"
-#include "python/swig/init.hh"
-#include "sim/async.hh"
-#include "sim/host.hh"
-#include "sim/core.hh"
-
-using namespace std;
-
-/// Stats signal handler.
-void
-dumpStatsHandler(int sigtype)
-{
-    async_event = true;
-    async_statdump = true;
-}
-
-void
-dumprstStatsHandler(int sigtype)
-{
-    async_event = true;
-    async_statdump = true;
-    async_statreset = true;
-}
-
-/// Exit signal handler.
-void
-exitNowHandler(int sigtype)
-{
-    async_event = true;
-    async_exit = true;
-}
-
-/// Abort signal handler.
-void
-abortHandler(int sigtype)
-{
-    ccprintf(cerr, "Program aborted at cycle %d\n", curTick);
-}
-
-int
-python_main()
-{
-    PyObject *module;
-    PyObject *dict;
-    PyObject *result;
-
-    module = PyImport_AddModule(const_cast<char*>("__main__"));
-    if (module == NULL)
-        fatal("Could not import __main__");
-
-    dict = PyModule_GetDict(module);
-
-    result = PyRun_String("import m5.main", Py_file_input, dict, dict);
-    if (!result) {
-        PyErr_Print();
-        return 1;
-    }
-    Py_DECREF(result);
-
-    result = PyRun_String("m5.main.main()", Py_file_input, dict, dict);
-    if (!result) {
-        PyErr_Print();
-        return 1;
-    }
-    Py_DECREF(result);
-
-    if (Py_FlushLine())
-        PyErr_Clear();
-
-    return 0;
-}
+#include "sim/init.hh"
 
+// main() is now pretty stripped down and just sets up python and then
+// calls initM5Python which loads the various embedded python modules
+// into the python environment and then starts things running by
+// calling m5Main.
 int
 main(int argc, char **argv)
 {
-    signal(SIGFPE, SIG_IGN);		// may occur on misspeculated paths
-    signal(SIGTRAP, SIG_IGN);
-    signal(SIGUSR1, dumpStatsHandler);		// dump intermediate stats
-    signal(SIGUSR2, dumprstStatsHandler);	// dump and reset stats
-    signal(SIGINT, exitNowHandler);		// dump final stats and exit
-    signal(SIGABRT, abortHandler);
-
-    Py_SetProgramName(argv[0]);
-
-    // default path to m5 python code is the currently executing
-    // file... Python ZipImporter will find embedded zip archive.
-    // The M5_ARCHIVE environment variable can be used to override this.
-    char *m5_archive = getenv("M5_ARCHIVE");
-    string pythonpath = m5_archive ? m5_archive : argv[0];
+    int ret;
 
-    char *oldpath = getenv("PYTHONPATH");
-    if (oldpath != NULL) {
-        pythonpath += ":";
-        pythonpath += oldpath;
-    }
-
-    if (setenv("PYTHONPATH", pythonpath.c_str(), true) == -1)
-        fatal("setenv: %s\n", strerror(errno));
+    // Initialize m5 special signal handling.
+    initSignals();
 
-    const char *python_home = getenv("PYTHONHOME");
-    if (!python_home)
-        python_home = PYTHONHOME;
-    Py_SetPythonHome(const_cast<char*>(python_home));
+    Py_SetProgramName(argv[0]);
 
     // initialize embedded Python interpreter
     Py_Initialize();
-    PySys_SetArgv(argc, argv);
 
-    // initialize SWIG modules
-    init_swig();
+    // Initialize the embedded m5 python library
+    ret = initM5Python();
 
-    int ret = python_main();
+    if (ret == 0) {
+        // start m5
+        ret = m5Main(argc, argv);
+    }
 
     // clean up Python intepreter.
     Py_Finalize();