Dynamic triggers for non-static contexts (#3599)

In non-static contexts like class objects or stack frames, the use of
global trigger evaluation is not feasible. The concept of dynamic
triggers allows for trigger evaluation in such cases. These triggers are
simply local variables, and coroutines are themselves responsible for
evaluating them. They await the global dynamic trigger scheduler object,
which is responsible for resuming them during the trigger evaluation
step in the 'act' eval region. Once the trigger is set, they await the
dynamic trigger scheduler once again, and then get resumed during the
resumption step in the 'act' eval region.

Signed-off-by: Krzysztof Bieganski <[email protected]>

include/verilated_timing.cpp

@@ -139,6 +139,54 @@ void VlTriggerScheduler::dump(const char* eventDescription) const {
 }
 #endif
 
+//======================================================================
+// VlDynamicTriggerScheduler:: Methods
+
+bool VlDynamicTriggerScheduler::evaluate() {
+    VL_DEBUG_IF(dump(););
+    std::swap(m_suspended, m_evaluated);
+    for (auto& coro : m_evaluated) coro.resume();
+    m_evaluated.clear();
+    return !m_triggered.empty();
+}
+
+void VlDynamicTriggerScheduler::doPostUpdates() {
+    VL_DEBUG_IF(if (!m_post.empty())
+                    VL_DBG_MSGF("         Doing post updates for processes:\n");  //
+                for (const auto& susp
+                     : m_post) {
+                    VL_DBG_MSGF("           - ");
+                    susp.dump();
+                });
+    for (auto& coro : m_post) coro.resume();
+    m_post.clear();
+}
+
+void VlDynamicTriggerScheduler::resume() {
+    VL_DEBUG_IF(if (!m_triggered.empty()) VL_DBG_MSGF("         Resuming processes:\n");  //
+                for (const auto& susp
+                     : m_triggered) {
+                    VL_DBG_MSGF("           - ");
+                    susp.dump();
+                });
+    for (auto& coro : m_triggered) coro.resume();
+    m_triggered.clear();
+}
+
+#ifdef VL_DEBUG
+void VlDynamicTriggerScheduler::dump() const {
+    if (m_suspended.empty()) {
+        VL_DBG_MSGF("         No suspended processes waiting for dynamic trigger evaluation\n");
+    } else {
+        for (const auto& susp : m_suspended) {
+            VL_DBG_MSGF("         Suspended processes waiting for dynamic trigger evaluation:\n");
+            VL_DBG_MSGF("           - ");
+            susp.dump();
+        }
+    }
+}
+#endif
+
 //======================================================================
 // VlForkSync:: Methods