Add assertion on reusing VerilatedContext (#5167).

Changes

@@ -30,6 +30,7 @@ Verilator 5.025 devel
 * Add parameterless assert control system tasks (#5010). [Bartłomiej Chmiel]
 * Add traceCapable indication to model header (#5053). [Vito Gamberini]
 * Add increasing of stack size when possible (#5071) (#5104). [Yinan Xu]
+* Add assertion on reusing VerilatedContext (#5167).
 * Improve DFG regularization in cyclic graphs (#5142). [Geza Lore]
 * Improve VerilatedVpiPutHolder storage requirements (#5144). [Kaleb Barrett]
 * Fix missing flex include path variable (#4970) (#4971). [Christopher Taylor]

include/verilated.cpp

@@ -2664,8 +2664,16 @@ void VerilatedContext::addModel(VerilatedModel* modelp) {
         m_ns.m_cpuTimeStart.start();
         m_ns.m_wallTimeStart.start();
     }
-    threadPoolp();  // Ensure thread pool is created, so m_threads cannot change any more
 
+    // We look for time passing, as opposed to post-eval(), as embedded
+    // models might get added inside initial blocks.
+    if (VL_UNLIKELY(time()))
+        VL_FATAL_MT(
+            __FILE__, __LINE__, "",
+            "Adding model when time is non-zero. ... Suggest check time(), or for restarting"
+            " model use a new VerilatedContext");
+
+    threadPoolp();  // Ensure thread pool is created, so m_threads cannot change any more
     m_threadsInModels += modelp->threads();
     if (VL_UNLIKELY(modelp->threads() > m_threads)) {
         std::ostringstream msg;

include/verilated_trace_imp.h

@@ -633,12 +633,13 @@ void VerilatedTrace<VL_SUB_T, VL_BUF_T>::addModel(VerilatedModel* modelp)
 
     // Validate
     if (!newModel) {  // LCOV_EXCL_START
-        VL_FATAL_MT(__FILE__, __LINE__, "",
-                    "The same model has already been added to this trace file");
+        VL_FATAL_MT(
+            __FILE__, __LINE__, "",
+            "The same model has already been added to this trace file or VerilatedContext");
     }
     if (VL_UNCOVERABLE(m_contextp && contextp != m_contextp)) {
         VL_FATAL_MT(__FILE__, __LINE__, "",
-                    "A trace file instance can only handle models from the same context");
+                    "A trace file instance can only handle models from the same VerilatedContext");
     }
     if (VL_UNCOVERABLE(m_didSomeDump)) {
         VL_FATAL_MT(__FILE__, __LINE__, "",

test_regress/t/t_leak.cpp

@@ -46,37 +46,20 @@ long long get_memory_usage() {
 }
 
 void make_and_destroy() {
-#ifdef VL_NO_LEGACY
     VerilatedContext* contextp = new VerilatedContext;
     contextp->debug(0);
     VM_PREFIX* topp = new VM_PREFIX{contextp};
-#else
-    Verilated::debug(0);
-    VM_PREFIX* topp = new VM_PREFIX;
-#endif
 
     topp->eval();
     topp->clk = true;
-    while (!
-#ifdef VL_NO_LEGACY
-           contextp->gotFinish()
-#else
-           Verilated::gotFinish()
-#endif
-    ) {
-#ifdef VL_NO_LEGACY
+    while (!contextp->gotFinish()) {
         contextp->timeInc(5);
-#else
-        main_time += 5;
-#endif
         topp->clk = !topp->clk;
         topp->eval();
     }
 
     VL_DO_DANGLING(delete topp, topp);
-#ifdef VL_NO_LEGACY
     VL_DO_DANGLING(delete contextp, contextp);
-#endif
 }
 
 int main(int argc, char* argv[]) {

test_regress/t/t_leak_legacy.pl

@@ -1,33 +0,0 @@
-#!/usr/bin/env perl
-if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
-# DESCRIPTION: Verilator: Verilog Test driver/expect definition
-#
-# Copyright 2003 by Wilson Snyder. This program is free software; you
-# can redistribute it and/or modify it under the terms of either the GNU
-# Lesser General Public License Version 3 or the Perl Artistic License
-# Version 2.0.
-# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
-
-if ($Self->{vltmt} && exists $ENV{TRAVIS_DIST} &&
-    $ENV{TRAVIS_DIST} eq "trusty")
-{
-    skip("Multithreaded test does not work under CI w/ Ubuntu Trusty");
-}
-
-scenarios(vlt_all => 1);
-
-top_filename("t/t_leak.v");
-
-compile(
-    make_top_shell => 0,
-    make_main => 0,
-    verilator_flags2 => ["--exe $Self->{t_dir}/t_leak.cpp"],
-    make_flags => 'CPPFLAGS_ADD=-UVL_NO_LEGACY',
-    );
-
-execute(
-    check_finished => 1,
-    );
-
-ok(1);
-1;

test_regress/t/t_timescale_parse.cpp

@@ -8,13 +8,14 @@
 
 VM_PREFIX* tb = nullptr;
 
-double sc_time_stamp() {
-    return 2 * 1e9;  // e.g. 2 seconds in ns units
-}
+double s_time = 0.0;
+
+double sc_time_stamp() { return s_time; }
 
 int main() {
     tb = new VM_PREFIX{"tb"};
 
+    s_time = 2 * 1e9;  // e.g. 2 seconds in ns units
     tb->eval();
     tb->eval();
     tb->eval();

test_regress/t/t_wrapper_reuse_context_bad.cpp

@@ -0,0 +1,24 @@
+//
+// DESCRIPTION: Verilator: Verilog Multiple Model Test Module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+#include <verilated.h>
+
+#include VM_PREFIX_INCLUDE
+
+int main(int argc, char** argv) {
+    // Create contexts
+    VerilatedContext* contextp{new VerilatedContext};
+
+    for (int i = 0; i < 2; ++i) {
+        std::unique_ptr<VM_PREFIX> topp{new VM_PREFIX{contextp, "TOP"}};
+        topp->eval();
+        contextp->timeInc(1);
+        topp->eval();
+    }
+
+    return 0;
+}

test_regress/t/t_wrapper_reuse_context_bad.out

@@ -0,0 +1,2 @@
+%Error: /svaha/wsnyder/SandBox/homecvs/v4/verilator/include/verilated.cpp:2672: Adding model when time is non-zero. ... Suggest check time(), or for restarting model use a new VerilatedContext
+Aborting...

test_regress/t/t_wrapper_reuse_context_bad.pl

@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use strict; use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Multiple Model Test Module
+#
+# Copyright 2024 by Wilson Snyder. 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-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+compile(
+    make_top_shell => 0,
+    make_main => 0,
+    verilator_flags2 => ["--exe $Self->{t_dir}/$Self->{name}.cpp"],
+    );
+
+execute(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;

test_regress/t/t_wrapper_reuse_context_bad.v

@@ -0,0 +1,9 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module top;
+   initial $finish;
+endmodule