systemc: Refactor sensitivities.

Dynamic and Static sensitivities used to be represented by the same
classes, even though they're (almost) disjoint in how they worked. Also
timeouts, which can be used alongside dynamic sensitivities, were
handled by the sensitivities themselves. That meant that the
sensitivity mechanism had to mix in more types of behaviors,
increasing complexity. Also, the non-standard timed_out function
Accellera includes is harder to implement if the path for timeouts and
regular sensitivities are mixed together.

This change splits up dynamic and static sensitivities and splits out
timeouts. It also immitates the ordering Accellera uses when going
through sensitivities for an event. Static sensitivities are triggered
first in reverse order (why?), and then dynamic sensitivities are
triggered in what amounts to reverse order. To delete a sensitivity
which has been handled, it's swapped with the one in the last position,
and then the vector is truncated to drop it at the end. This has the
net effect of stirring the dynamic sensitivities, and isn't easily
immitated using a different approach, even if other approaches would
be more straightforward.

Double check addSensitivity for event.hh

Change-Id: I1e73dce386b95f68e9d6737deb8bed70ef717e0d
Reviewed-on: https://gem5-review.googlesource.com/c/12805
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

1 files changed, 182 insertions, 0 deletions

diff --git a/src/systemc/core/sensitivity.cc b/src/systemc/core/sensitivity.cc
new file mode 100644
index 000000000..77aacb56a
--- /dev/null
+++ b/src/systemc/core/sensitivity.cc
@@ -0,0 +1,182 @@
+/*
+ * Copyright 2018 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 "systemc/core/sensitivity.hh"
+
+#include "systemc/core/event.hh"
+#include "systemc/core/scheduler.hh"
+#include "systemc/ext/core/sc_export.hh"
+#include "systemc/ext/core/sc_interface.hh"
+#include "systemc/ext/core/sc_port.hh"
+
+namespace sc_gem5
+{
+
+void
+Sensitivity::satisfy()
+{
+    process->satisfySensitivity(this);
+}
+
+bool
+Sensitivity::notify(Event *e)
+{
+    if (process->disabled())
+        return false;
+    return notifyWork(e);
+}
+
+
+void
+DynamicSensitivity::addToEvent(const ::sc_core::sc_event *e)
+{
+    Event::getFromScEvent(e)->addSensitivity(this);
+}
+
+void
+DynamicSensitivity::delFromEvent(const ::sc_core::sc_event *e)
+{
+    Event::getFromScEvent(e)->delSensitivity(this);
+}
+
+void
+StaticSensitivity::addToEvent(const ::sc_core::sc_event *e)
+{
+    Event::getFromScEvent(e)->addSensitivity(this);
+}
+
+void
+StaticSensitivity::delFromEvent(const ::sc_core::sc_event *e)
+{
+    Event::getFromScEvent(e)->delSensitivity(this);
+}
+
+void
+StaticSensitivityInterface::finalize()
+{
+    event = &interface->default_event();
+    SensitivityEvent::finalize();
+}
+
+void
+StaticSensitivityPort::finalize()
+{
+    for (int i = 0; i < port->size(); i++) {
+        const ::sc_core::sc_event *event =
+            &port->_gem5Interface(i)->default_event();
+        events.insert(event);
+        addToEvent(event);
+    }
+}
+
+void
+StaticSensitivityExport::finalize()
+{
+    event = &exp->get_interface()->default_event();
+    SensitivityEvent::finalize();
+}
+
+void
+StaticSensitivityFinder::finalize()
+{
+    const ::sc_core::sc_port_base *port = finder->port();
+    int size = port->size();
+    for (int i = 0; i < size; i++) {
+        ::sc_core::sc_interface *interface = port->_gem5Interface(i);
+        const ::sc_core::sc_event *event = &finder->find_event(interface);
+        events.insert(event);
+        addToEvent(event);
+    }
+}
+
+bool
+DynamicSensitivityEventOrList::notifyWork(Event *e)
+{
+    events.erase(e->sc_event());
+
+    // All the other events need this deleted from their lists since this
+    // sensitivity has been satisfied without them triggering.
+    for (auto le: events)
+        delFromEvent(le);
+
+    satisfy();
+    return true;
+}
+
+DynamicSensitivityEventOrList::DynamicSensitivityEventOrList(
+        Process *p, const sc_core::sc_event_or_list *eol) :
+    Sensitivity(p), DynamicSensitivity(p), events(eol->events)
+{}
+
+void
+DynamicSensitivityEventOrList::finalize()
+{
+    for (auto e: events)
+        addToEvent(e);
+}
+
+void
+DynamicSensitivityEventOrList::clear()
+{
+    for (auto e: events)
+        delFromEvent(e);
+}
+
+bool
+DynamicSensitivityEventAndList::notifyWork(Event *e)
+{
+    events.erase(e->sc_event());
+
+    // This sensitivity is satisfied if all events have triggered.
+    if (events.empty())
+        satisfy();
+
+    return true;
+}
+
+DynamicSensitivityEventAndList::DynamicSensitivityEventAndList(
+        Process *p, const sc_core::sc_event_and_list *eal) :
+    Sensitivity(p), DynamicSensitivity(p), events(eal->events)
+{}
+
+void
+DynamicSensitivityEventAndList::finalize()
+{
+    for (auto e: events)
+        addToEvent(e);
+}
+
+void
+DynamicSensitivityEventAndList::clear()
+{
+    for (auto e: events)
+        delFromEvent(e);
+}
+
+} // namespace sc_gem5