sc_event::none - convert from global variable to function

The sc_event::none variable was introduced in
55da81d. The problem with the
introduced implementation is that the created event contains a
reference to the simulation context. This simulation context is created
by the sc_event constructor through the invocation of
sc_get_curr_simcontext() on program startup.

This commit proposes a change which tracks the none event as part of the
simulation context. The change converts sc_event::none to a static
member function which returns a reference to the m_none member of the
current simulation context. This eases reset of the simulation context
as discussed in accellera-official#8.

Neither sc_event::none nor sc_get_curr_simcontext() are currently
mandated by IEEE Std 1666-2011. For this reason, this change should not
affected existing standard-conforming SystemC programs.

Signed-off-by: Sören Tempel <[email protected]>

src/sysc/communication/sc_event_finder.h

@@ -150,7 +150,7 @@ sc_event_finder_t<IF>::find_event( sc_interface* if_p ) const
                                  dynamic_cast<const IF*>( port().get_interface() );
     if( iface == 0 ) {
         report_error( SC_ID_FIND_EVENT_, "port is not bound" );
-        return sc_event::none;
+        return sc_event::none();
     }
     return (const_cast<IF*>( iface )->*m_event_method) ();
 }

src/sysc/communication/sc_interface.cpp

@@ -52,7 +52,7 @@ const sc_event&
 sc_interface::default_event() const
 {
     SC_REPORT_WARNING( SC_ID_NO_DEFAULT_EVENT_, 0 );
-    return sc_event::none;
+    return sc_event::none();
 }
 
 

src/sysc/kernel/sc_event.cpp

@@ -52,9 +52,6 @@ using std::strncmp;
 //  The event class.
 // ----------------------------------------------------------------------------
 
-// kernel-internal event, that is never notified
-const sc_event sc_event::none( kernel_event, "none" );
-
 const char*
 sc_event::basename() const
 {

src/sysc/kernel/sc_event.h

@@ -300,8 +300,13 @@ class SC_API sc_event
     // has this event been triggered in the current delta cycle?
     bool triggered() const;
 
-    // never notified event
-    static const sc_event none;
+    // returns never notified event
+    static const sc_event& none(void) {
+        sc_simcontext *sc = sc_get_curr_simcontext();
+        if (!sc->m_none_event)
+            sc->m_none_event = new sc_event(sc_event::kernel_event, "none");
+        return *sc->m_none_event;
+    }
 
 private:
 

src/sysc/kernel/sc_simcontext.cpp

@@ -358,6 +358,7 @@ sc_simcontext::init()
     m_method_invoker_p = NULL;
     m_cor = 0;
     m_reset_finder_q = 0;
+    m_none_event = NULL;
     m_in_simulator_control = false;
     m_start_of_simulation_called = false;
     m_end_of_simulation_called = false;
@@ -370,6 +371,9 @@ sc_simcontext::clean()
     // remove remaining zombie processes
     do_collect_processes();
 
+    if (m_none_event)
+        delete m_none_event;
+
     delete m_method_invoker_p;
     delete m_error;
     delete m_cor_pkg;

src/sysc/kernel/sc_simcontext.h

@@ -399,6 +399,8 @@ class SC_API sc_simcontext
 
     sc_reset_finder*            m_reset_finder_q; // Q of reset finders to reconcile.
 
+    sc_event*                   m_none_event; // never notified event
+
 private:
 
     // disabled

src/tlm_core/tlm_1/tlm_req_rsp/tlm_ports/tlm_event_finder.h

@@ -66,7 +66,7 @@ tlm_event_finder_t<IF,T>::find_event( sc_core::sc_interface* if_p ) const
                                  dynamic_cast<const IF*>( port().get_interface() );
     if( iface == 0 ) {
         report_error( sc_core::SC_ID_FIND_EVENT_, "port is not bound" );
-        return sc_core::sc_event::none;
+        return sc_core::sc_event::none();
     }
     return (const_cast<IF*>( iface )->*m_event_method) ( 0 );
 }