systemc: Export the sc_core::sc_time class to python.

This class isn't incredibly useful in python, but it's needed to call
some other functions which are more useful.

Change-Id: I5c23cca0b50f0455423399db8b009bdf86a6ec41
Reviewed-on: https://gem5-review.googlesource.com/c/16502
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
diff --git a/src/systemc/core/SConscript b/src/systemc/core/SConscript
index 536c181..f086112 100644
--- a/src/systemc/core/SConscript
+++ b/src/systemc/core/SConscript
@@ -64,3 +64,4 @@
     if env['USE_PYTHON']:
         Source('python.cc')
         Source('sc_main_python.cc')
+        Source('sc_time_python.cc')
diff --git a/src/systemc/core/SystemC.py b/src/systemc/core/SystemC.py
index 7ab33ea..7afbd28 100644
--- a/src/systemc/core/SystemC.py
+++ b/src/systemc/core/SystemC.py
@@ -36,6 +36,12 @@
     cxx_class = 'sc_gem5::Kernel'
     cxx_header = 'systemc/core/kernel.hh'
 
+    # The sc_time type won't exist until some setup code runs in gem5.
+    try:
+        from _m5.systemc import sc_time
+    except:
+        pass
+
     class ScMainResult(object):
         def __init__(self, code, message):
             self.code = code
diff --git a/src/systemc/core/sc_time_python.cc b/src/systemc/core/sc_time_python.cc
new file mode 100644
index 0000000..8696be1
--- /dev/null
+++ b/src/systemc/core/sc_time_python.cc
@@ -0,0 +1,82 @@
+/*
+ * Copyright 2019 Google, Inc.
+ *
+ * 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: Gabe Black
+ */
+
+#include "pybind11/operators.h"
+
+#include "systemc/core/python.hh"
+#include "systemc/ext/core/sc_time.hh"
+
+namespace
+{
+
+struct InstallScTime : public ::sc_gem5::PythonInitFunc
+{
+    void
+    run(pybind11::module &systemc) override
+    {
+        pybind11::class_<sc_core::sc_time> sc_time(systemc, "sc_time");
+        sc_time
+            // Constructors (omitting nonstandard and deprecated)
+            .def(pybind11::init<>())
+            .def(pybind11::init<double, sc_core::sc_time_unit>())
+            .def(pybind11::init<const sc_core::sc_time &>())
+
+            // Converters.
+            .def("value", &sc_core::sc_time::value)
+            .def("to_double", &sc_core::sc_time::to_double)
+            .def("to_seconds", &sc_core::sc_time::to_seconds)
+            .def("to_string", &sc_core::sc_time::to_string)
+            .def("__str__", &sc_core::sc_time::to_string)
+
+            // Operators.
+            .def(pybind11::self == pybind11::self)
+            .def(pybind11::self != pybind11::self)
+            .def(pybind11::self < pybind11::self)
+            .def(pybind11::self <= pybind11::self)
+            .def(pybind11::self > pybind11::self)
+            .def(pybind11::self >= pybind11::self)
+            .def(pybind11::self += pybind11::self)
+            .def(pybind11::self -= pybind11::self)
+            .def(pybind11::self *= double())
+            .def(pybind11::self /= double())
+            ;
+
+        pybind11::enum_<sc_core::sc_time_unit>(sc_time, "sc_time_unit")
+            .value("SC_FS", sc_core::SC_FS)
+            .value("SC_PS", sc_core::SC_PS)
+            .value("SC_NS", sc_core::SC_NS)
+            .value("SC_US", sc_core::SC_US)
+            .value("SC_MS", sc_core::SC_MS)
+            .value("SC_SEC", sc_core::SC_SEC)
+            .export_values()
+            ;
+    }
+} installScTime;
+
+} // anonymous namespace