From e6b19d557e848ec0077f4847cd19ddf0f2a46660 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 14 Mar 2021 09:08:17 -0400
Subject: [PATCH] Fix false $dumpfile warning on model save (#2834).

---
 Changes               | 2 ++
 include/verilated.cpp | 8 ++++++--
 include/verilated.h   | 1 +
 src/V3EmitC.cpp       | 2 +-
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/Changes b/Changes
index 841cb887d..a39db2e05 100644
--- a/Changes
+++ b/Changes
@@ -10,6 +10,8 @@ The contributors that suggested a given feature are shown in []. Thanks!
 
 ****  Fix exceeding command-line ar limit (#2834). [Yinan Xu]
 
+****  Fix false $dumpfile warning on model save (#2834). [Yinan Xu]
+
 
 * Verilator 4.200 2021-03-12
 
diff --git a/include/verilated.cpp b/include/verilated.cpp
index 3d3f8bddc..0ee5a46e6 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -2202,11 +2202,15 @@ void VerilatedContext::dumpfile(const std::string& flag) VL_MT_SAFE_EXCLUDES(m_t
 }
 std::string VerilatedContext::dumpfile() const VL_MT_SAFE_EXCLUDES(m_timeDumpMutex) {
     const VerilatedLockGuard lock(m_timeDumpMutex);
-    if (VL_UNLIKELY(m_dumpfile.empty())) {
+    return m_dumpfile;
+}
+std::string VerilatedContext::dumpfileCheck() const VL_MT_SAFE_EXCLUDES(m_timeDumpMutex) {
+    const std::string out = dumpfile();
+    if (VL_UNLIKELY(out.empty())) {
         VL_PRINTF_MT("%%Warning: $dumpvar ignored as not proceeded by $dumpfile\n");
         return "";
     }
-    return m_dumpfile;
+    return out;
 }
 void VerilatedContext::errorCount(int val) VL_MT_SAFE {
     const VerilatedLockGuard lock(m_mutex);
diff --git a/include/verilated.h b/include/verilated.h
index 980beda10..49997bcbc 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -529,6 +529,7 @@ public:  // But for internal use only
     // Internal: $dumpfile
     void dumpfile(const std::string& flag) VL_MT_SAFE_EXCLUDES(m_timeDumpMutex);
     std::string dumpfile() const VL_MT_SAFE_EXCLUDES(m_timeDumpMutex);
+    std::string dumpfileCheck() const VL_MT_SAFE_EXCLUDES(m_timeDumpMutex);
 
     // Internal: --prof-threads related settings
     void profThreadsStart(vluint64_t flag) VL_MT_SAFE;
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index d231f37d5..0ea41997c 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -3523,7 +3523,7 @@ class EmitCTrace final : EmitCStmts {
             puts("if (VL_UNLIKELY(!__VlSymsp->__Vm_dumperp)) {\n");
             puts("__VlSymsp->__Vm_dumperp = new " + v3Global.opt.traceClassLang() + "();\n");
             puts("trace(__VlSymsp->__Vm_dumperp, 0, 0);\n");
-            puts("std::string dumpfile = __VlSymsp->_vm_contextp__->dumpfile();\n");
+            puts("std::string dumpfile = __VlSymsp->_vm_contextp__->dumpfileCheck();\n");
             puts("__VlSymsp->__Vm_dumperp->open(dumpfile.c_str());\n");
             puts("__VlSymsp->__Vm_dumping = true;\n");
             puts("}\n");