From ed93a111c285ce36e185ed45a45cf9e0d33c9b6a Mon Sep 17 00:00:00 2001
From: Kamil Rakoczy <krakoczy@antmicro.com>
Date: Wed, 26 Oct 2022 13:50:28 +0200
Subject: [PATCH] Fix deadlock in ``timeprecision`` when using systemC (#3707)

---
 include/verilated.cpp               | 36 ++++++++++++++++-------------
 test_regress/t/t_time_sc_bad_mt.out |  2 ++
 test_regress/t/t_time_sc_bad_mt.pl  | 30 ++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 16 deletions(-)
 create mode 100644 test_regress/t/t_time_sc_bad_mt.out
 create mode 100755 test_regress/t/t_time_sc_bad_mt.pl

diff --git a/include/verilated.cpp b/include/verilated.cpp
index 506c1e5f7..6428c4ee5 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -2426,23 +2426,25 @@ void VerilatedContext::timeunit(int value) VL_MT_SAFE {
 }
 void VerilatedContext::timeprecision(int value) VL_MT_SAFE {
     if (value < 0) value = -value;  // Stored as 0..15
-    const VerilatedLockGuard lock{m_mutex};
-    m_s.m_timeprecision = value;
-#ifdef SYSTEMC_VERSION
-    const sc_time sc_res = sc_get_time_resolution();
     int sc_prec = 99;
-    if (sc_res == sc_time(1, SC_SEC)) {
-        sc_prec = 0;
-    } else if (sc_res == sc_time(1, SC_MS)) {
-        sc_prec = 3;
-    } else if (sc_res == sc_time(1, SC_US)) {
-        sc_prec = 6;
-    } else if (sc_res == sc_time(1, SC_NS)) {
-        sc_prec = 9;
-    } else if (sc_res == sc_time(1, SC_PS)) {
-        sc_prec = 12;
-    } else if (sc_res == sc_time(1, SC_FS)) {
-        sc_prec = 15;
+    {
+        const VerilatedLockGuard lock{m_mutex};
+        m_s.m_timeprecision = value;
+#ifdef SYSTEMC_VERSION
+        const sc_time sc_res = sc_get_time_resolution();
+        if (sc_res == sc_time(1, SC_SEC)) {
+            sc_prec = 0;
+        } else if (sc_res == sc_time(1, SC_MS)) {
+            sc_prec = 3;
+        } else if (sc_res == sc_time(1, SC_US)) {
+            sc_prec = 6;
+        } else if (sc_res == sc_time(1, SC_NS)) {
+            sc_prec = 9;
+        } else if (sc_res == sc_time(1, SC_PS)) {
+            sc_prec = 12;
+        } else if (sc_res == sc_time(1, SC_FS)) {
+            sc_prec = 15;
+        }
     }
     if (value != sc_prec) {
         std::ostringstream msg;
@@ -2454,6 +2456,8 @@ void VerilatedContext::timeprecision(int value) VL_MT_SAFE {
         const std::string msgs = msg.str();
         VL_FATAL_MT("", 0, "", msgs.c_str());
     }
+#else
+    }
 #endif
 }
 const char* VerilatedContext::timeunitString() const VL_MT_SAFE { return vl_time_str(timeunit()); }
diff --git a/test_regress/t/t_time_sc_bad_mt.out b/test_regress/t/t_time_sc_bad_mt.out
new file mode 100644
index 000000000..86603162d
--- /dev/null
+++ b/test_regress/t/t_time_sc_bad_mt.out
@@ -0,0 +1,2 @@
+%Error: SystemC's sc_set_time_resolution is 10^-9, which does not match Verilog timeprecision 10^-12. Suggest use 'sc_set_time_resolution(1s)', or Verilator '--timescale-override 1s/1s'
+Aborting...
diff --git a/test_regress/t/t_time_sc_bad_mt.pl b/test_regress/t/t_time_sc_bad_mt.pl
new file mode 100755
index 000000000..6b6f6d637
--- /dev/null
+++ b/test_regress/t/t_time_sc_bad_mt.pl
@@ -0,0 +1,30 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vltmt => 1);
+
+top_filename("t/t_time_sc.v");
+
+$Self->{sc_time_resolution} = 'SC_NS';
+
+compile(
+    verilator_flags2 => ['-sc', '-timescale 1ps/1ps',  # Mismatch w/sc_time_resolution
+                         '+define+TEST_EXPECT=2us'],
+    threads => 2,
+    );
+
+execute(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+
+1;