Fix `$finish` to immediately stop executing code from non-final blocks (#7213 partial) (#7390)

Signed-off-by: Artur Bieniek <abieniek@antmicro.com>

include/verilated_timing.cpp

@@ -58,6 +58,12 @@ void VlDelayScheduler::resume() {
 #ifdef VL_DEBUG
     VL_DEBUG_IF(dump(); VL_DBG_MSGF("         Resuming delayed processes\n"););
 #endif
+    if (VL_UNLIKELY(m_context.gotFinish())) {
+        m_queue.clear();
+        m_zeroDelayed.clear();
+        m_zeroDelayesSwap.clear();
+        return;
+    }
     bool resumed = false;
 
     while (!m_queue.empty() && (m_queue.cbegin()->first == m_context.time())) {
@@ -80,6 +86,11 @@ void VlDelayScheduler::resume() {
 }
 
 void VlDelayScheduler::resumeZeroDelay() {
+    if (VL_UNLIKELY(m_context.gotFinish())) {
+        m_zeroDelayed.clear();
+        m_zeroDelayesSwap.clear();
+        return;
+    }
     m_zeroDelayesSwap.swap(m_zeroDelayed);
     for (VlCoroutineHandle& handle : m_zeroDelayesSwap) handle.resume();
     m_zeroDelayesSwap.clear();
@@ -120,6 +131,12 @@ void VlTriggerScheduler::resume(const char* eventDescription) {
     VL_DEBUG_IF(dump(eventDescription);
                 VL_DBG_MSGF("         Resuming processes waiting for %s\n", eventDescription););
 #endif
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_toResume.clear();
+        m_fired.clear();
+        m_awaiting.clear();
+        return;
+    }
     for (VlCoroutineHandle& coro : m_toResume) coro.resume();
     m_toResume.clear();
 }
@@ -136,6 +153,11 @@ void VlTriggerScheduler::moveToResumeQueue(const char* eventDescription) {
                     });
     }
 #endif
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_toResume.clear();
+        m_fired.clear();
+        return;
+    }
     std::swap(m_fired, m_toResume);
 }
 
@@ -151,6 +173,11 @@ void VlTriggerScheduler::ready(const char* eventDescription) {
             });
     }
 #endif
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_fired.clear();
+        m_awaiting.clear();
+        return;
+    }
     const size_t expectedSize = m_fired.size() + m_awaiting.size();
     if (m_fired.capacity() < expectedSize) m_fired.reserve(expectedSize * 2);
     m_fired.insert(m_fired.end(), std::make_move_iterator(m_awaiting.begin()),
@@ -190,6 +217,14 @@ void VlTriggerScheduler::dump(const char* eventDescription) const {
 // VlDynamicTriggerScheduler:: Methods
 
 bool VlDynamicTriggerScheduler::evaluate() {
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_anyTriggered = false;
+        m_suspended.clear();
+        m_evaluated.clear();
+        m_triggered.clear();
+        m_post.clear();
+        return false;
+    }
     m_anyTriggered = false;
     VL_DEBUG_IF(dump(););
     std::swap(m_suspended, m_evaluated);
@@ -206,6 +241,10 @@ void VlDynamicTriggerScheduler::doPostUpdates() {
                     VL_DBG_MSGF("           - ");
                     susp.dump();
                 });
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_post.clear();
+        return;
+    }
     for (auto& coro : m_post) coro.resume();
     m_post.clear();
 }
@@ -217,6 +256,10 @@ void VlDynamicTriggerScheduler::resume() {
                     VL_DBG_MSGF("           - ");
                     susp.dump();
                 });
+    if (VL_UNLIKELY(Verilated::threadContextp()->gotFinish())) {
+        m_triggered.clear();
+        return;
+    }
     for (auto& coro : m_triggered) coro.resume();
     m_triggered.clear();
 }

include/verilated_timing.h

@@ -190,10 +190,11 @@ public:
     bool empty() const { return m_queue.empty() && m_zeroDelayed.empty(); }
     // Are there coroutines to resume at the current simulation time?
     bool awaitingCurrentTime() const {
-        return (!m_queue.empty() && (m_queue.cbegin()->first <= m_context.time()));
+        return !m_context.gotFinish()
+               && (!m_queue.empty() && (m_queue.cbegin()->first <= m_context.time()));
     }
     // Are there coroutines to resume in the inactive region after a #0 delay?
-    bool awaitingZeroDelay() const { return !m_zeroDelayed.empty(); }
+    bool awaitingZeroDelay() const { return !m_context.gotFinish() && !m_zeroDelayed.empty(); }
 #ifdef VL_DEBUG
     void dump() const;
 #endif

test_regress/t/t_finish_stops_nonfinal.py

@@ -0,0 +1,18 @@
+#!/usr/bin/env python3
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of either the GNU Lesser General Public License Version 3
+# or the Perl Artistic License Version 2.0.
+# SPDX-FileCopyrightText: 2026 Wilson Snyder
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+import vltest_bootstrap
+
+test.scenarios('simulator')
+
+test.compile(make_main=False, verilator_flags2=["--binary"])
+
+test.execute()
+
+test.passes()

test_regress/t/t_finish_stops_nonfinal.v

@@ -0,0 +1,26 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain
+// SPDX-FileCopyrightText: 2026 Antmicro
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+  bit clk = 0;
+  int cyc = 0;
+
+  initial forever #1 clk = ~clk;
+
+  always @(posedge clk) begin
+    cyc = cyc + 1;
+    if (cyc >= 10) $finish;
+  end
+
+  always @(posedge clk) begin
+    fork
+      begin
+        while ($sampled(cyc) != 99) #1;
+        if (cyc >= 10) $stop;
+      end
+    join_none
+  end
+endmodule

test_regress/t/t_timing_debug1.out

@@ -4159,8 +4159,6 @@
 -V{t#,#}+    Vt_timing_debug1___024root___trigger_anySet__act
 -V{t#,#}+    Vt_timing_debug1___024root___timing_resume
 -V{t#,#}         No process to resume waiting for @(posedge t.clk1)
--V{t#,#}         Not triggered processes waiting for @(posedge t.clk1):
--V{t#,#}           - Process waiting at t/t_timing_sched.v:18
 -V{t#,#}         Resuming processes waiting for @(posedge t.clk1)
 -V{t#,#}         No process to resume waiting for @(posedge t.clk2)
 -V{t#,#}         Resuming processes waiting for @(posedge t.clk2)

test_regress/t/t_timing_debug2.out

@@ -1666,7 +1666,6 @@
 -V{t#,#}+        Vt_timing_debug2_t__03a__03aClkClass::__VnoInFunc_flip
 -V{t#,#}+    Vt_timing_debug2___024root___eval_phase__act
 -V{t#,#}+    Vt_timing_debug2___024root___eval_triggers_vec__act
--V{t#,#}         No suspended processes waiting for dynamic trigger evaluation
 -V{t#,#}+    Vt_timing_debug2___024root___timing_ready
 -V{t#,#}+    Vt_timing_debug2___024root___trigger_orInto__act_vec_vec
 -V{t#,#}+    Vt_timing_debug2___024root___dump_triggers__act
@@ -1681,7 +1680,6 @@
 -V{t#,#}+    Vt_timing_debug2___024root___trigger_clear__act
 -V{t#,#}+    Vt_timing_debug2___024root___eval_phase__act
 -V{t#,#}+    Vt_timing_debug2___024root___eval_triggers_vec__act
--V{t#,#}         No suspended processes waiting for dynamic trigger evaluation
 -V{t#,#}+    Vt_timing_debug2___024root___timing_ready
 -V{t#,#}+    Vt_timing_debug2___024root___trigger_orInto__act_vec_vec
 -V{t#,#}+    Vt_timing_debug2___024root___dump_triggers__act