Make sc_event thread safe

Signed-off-by: Mark Burton <mburton@quicinc.com>

Author: markfoodyburton

src/sysc/kernel/sc_event.cpp

@@ -30,6 +30,7 @@
 #include <cstring>
 
 #include "sysc/kernel/sc_event.h"
+#include "sc_simcontext.h"
 #include "sysc/kernel/sc_kernel_ids.h"
 #include "sysc/kernel/sc_stage_callback_registry.h"
 #include "sysc/kernel/sc_process.h"
@@ -61,6 +62,10 @@ sc_event::basename() const
 void
 sc_event::cancel()
 {
+    if (m_simc != sc_get_curr_simcontext()) {
+        async_helper.pending_cancel();
+        return;
+    }
     // cancel a delta or timed notification
     switch( m_notify_type ) {
     case DELTA: {
@@ -86,6 +91,10 @@ sc_event::cancel()
 void
 sc_event::notify()
 {
+    if (m_simc != sc_get_curr_simcontext()) {
+        async_helper.pending_notify(SC_ZERO_TIME);
+        return;
+    }
     // immediate notification
     if( !m_simc->evaluation_phase() )
         // coming from
@@ -103,6 +112,10 @@ sc_event::notify()
 void
 sc_event::notify( const sc_time& t )
 {
+    if (m_simc != sc_get_curr_simcontext()) {
+        async_helper.pending_notify(t);
+        return;
+    }
     if( m_notify_type == DELTA ) {
         return;
     }

src/sysc/kernel/sc_event.h

@@ -35,6 +35,7 @@
 #include "sysc/kernel/sc_simcontext.h"
 #include "sysc/communication/sc_writer_policy.h"
 #include "sysc/utils/sc_ptr_flag.h"
+#include <mutex>
 
 #if defined(_MSC_VER) && !defined(SC_WIN_DLL_WARN)
 #pragma warning(push)
@@ -273,6 +274,43 @@ class SC_API sc_event
     friend class sc_join;
     friend class sc_trace_file;
 
+    class pending_helper : public sc_core::sc_stage_callback_if
+    {
+        std::mutex mutex;
+        class sc_event *event;
+
+        bool valid=false;
+        bool cancel=false;
+        sc_time time;
+
+        void stage_callback(const sc_core::sc_stage& stage) {
+        mutex.lock();
+            if (valid) {
+                if (cancel) event->cancel();
+                else event->notify(time);
+            }
+            valid=false;
+            mutex.unlock();
+        }
+
+        public:
+        void pending_notify(sc_time t) {
+            mutex.lock();
+            time=t;
+            valid=true;
+            mutex.unlock();
+            sc_core::sc_register_stage_callback(*this, sc_core::SC_POST_UPDATE);
+        }
+        void pending_cancel() {
+            mutex.lock();
+            valid=true;
+            cancel=true;
+            mutex.unlock();
+            sc_core::sc_register_stage_callback(*this, sc_core::SC_POST_UPDATE);
+        }
+
+    };
+    pending_helper async_helper;
 public:
 
     sc_event();