systemc: Improve scheduler cleanup.

Make the scheduler clear itself out when it's destructed to ensure that
nobody will try to use it after it's gone away. Also make sure there
are no pending events which might refer to it as well, either systemc
events or gem5 events.

Change-Id: I12dadc06bd9db7016a8dc0c1827b3e630b0d23d5
Reviewed-on: https://gem5-review.googlesource.com/12222
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

7 files changed, 91 insertions, 0 deletions

diff --git a/src/systemc/core/SConscript b/src/systemc/core/SConscript
index 76327c860..4814e6afa 100644
--- a/src/systemc/core/SConscript
+++ b/src/systemc/core/SConscript
@@ -39,6 +39,7 @@ if env['USE_SYSTEMC']:
     Source('process_types.cc')
     Source('python.cc')
     Source('scheduler.cc')
+    Source('sched_event.cc')
 
     Source('sc_attr.cc')
     Source('sc_event.cc')
diff --git a/src/systemc/core/channel.cc b/src/systemc/core/channel.cc
index 49d9f6cb7..04f158bea 100644
--- a/src/systemc/core/channel.cc
+++ b/src/systemc/core/channel.cc
@@ -41,6 +41,7 @@ Channel::Channel(sc_core::sc_prim_channel *_sc_chan) : _sc_chan(_sc_chan)
 
 Channel::~Channel()
 {
+    popListNode();
     allChannels.erase(this);
 }
 
diff --git a/src/systemc/core/process.hh b/src/systemc/core/process.hh
index 25d3e4eb0..267a7ed3d 100644
--- a/src/systemc/core/process.hh
+++ b/src/systemc/core/process.hh
@@ -330,6 +330,7 @@ class Process : public ::sc_core::sc_object, public ListNode
 
     virtual ~Process()
     {
+        popListNode();
         delete func;
         for (auto s: staticSensitivities)
             delete s;
diff --git a/src/systemc/core/sched_event.cc b/src/systemc/core/sched_event.cc
new file mode 100644
index 000000000..576c23ba8
--- /dev/null
+++ b/src/systemc/core/sched_event.cc
@@ -0,0 +1,43 @@
+/*
+ * 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/sched_event.hh"
+
+#include "systemc/core/scheduler.hh"
+
+namespace sc_gem5
+{
+
+ScEvent::~ScEvent()
+{
+    if (scheduled())
+        scheduler.deschedule(this);
+}
+
+} // namespace sc_gem5
diff --git a/src/systemc/core/sched_event.hh b/src/systemc/core/sched_event.hh
index 63b76ef0a..9aefb7440 100644
--- a/src/systemc/core/sched_event.hh
+++ b/src/systemc/core/sched_event.hh
@@ -59,6 +59,8 @@ class ScEvent
         work(work), _when(MaxTick), _scheduled(false)
     {}
 
+    ~ScEvent();
+
     bool scheduled() { return _scheduled; }
 
     void when(Tick w) { _when = w; }
diff --git a/src/systemc/core/scheduler.cc b/src/systemc/core/scheduler.cc
index cdebd9986..6762086a0 100644
--- a/src/systemc/core/scheduler.cc
+++ b/src/systemc/core/scheduler.cc
@@ -50,6 +50,48 @@ Scheduler::Scheduler() :
     runOnce(false)
 {}
 
+Scheduler::~Scheduler()
+{
+    // Clear out everything that belongs to us to make sure nobody tries to
+    // clear themselves out after the scheduler goes away.
+
+    // Delta notifications.
+    for (auto &e: deltas)
+        e->deschedule();
+
+    // Timed notifications.
+    for (auto &ts: timeSlots) {
+        for (auto &e: ts.second->events)
+            e->deschedule();
+        delete ts.second;
+        ts.second = nullptr;
+    }
+
+    // gem5 events.
+    if (readyEvent.scheduled())
+        eq->deschedule(&readyEvent);
+    if (pauseEvent.scheduled())
+        eq->deschedule(&pauseEvent);
+    if (stopEvent.scheduled())
+        eq->deschedule(&stopEvent);
+    if (starvationEvent.scheduled())
+        eq->deschedule(&starvationEvent);
+    if (maxTickEvent.scheduled())
+        eq->deschedule(&maxTickEvent);
+
+    Process *p;
+    while ((p = toFinalize.getNext()))
+        p->popListNode();
+    while ((p = initList.getNext()))
+        p->popListNode();
+    while ((p = readyList.getNext()))
+        p->popListNode();
+
+    Channel *c;
+    while ((c = updateList.getNext()))
+        c->popListNode();
+}
+
 void
 Scheduler::initPhase()
 {
diff --git a/src/systemc/core/scheduler.hh b/src/systemc/core/scheduler.hh
index c22bdf870..24b7fd2ff 100644
--- a/src/systemc/core/scheduler.hh
+++ b/src/systemc/core/scheduler.hh
@@ -159,6 +159,7 @@ class Scheduler
     typedef std::map<Tick, TimeSlot *> TimeSlots;
 
     Scheduler();
+    ~Scheduler();
 
     const std::string name() const { return "systemc_scheduler"; }