From 495585830d5fa58cfb450aa42db98a7951c8802e Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Mon, 22 Mar 2010 18:38:24 -0400
Subject: [PATCH] Fix trace files with empty modules crashing some viewers.

---
 Changes                     |  4 +++-
 include/verilated_vcd_c.cpp | 45 +++++++++++++++++++++++++++++--------
 include/verilated_vcd_c.h   |  1 +
 3 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/Changes b/Changes
index 6af2a885e..f581a6e8b 100644
--- a/Changes
+++ b/Changes
@@ -7,9 +7,11 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ***  Support runtime access to public signal names.
 
+**** Improve error handling on slices of arrays, bug226. [by Bryon Bradley]
+
 **** Fix "make install" with configure outside srcdir.  [Stefan Wallentowitz]
 
-**** Improve error handling on slices of arrays, bug226. [by Bryon Bradley]
+**** Fix trace files with empty modules crashing some viewers.
 
 * Verilator 3.801 2010/03/17
 
diff --git a/include/verilated_vcd_c.cpp b/include/verilated_vcd_c.cpp
index 94269fb76..d86dab751 100644
--- a/include/verilated_vcd_c.cpp
+++ b/include/verilated_vcd_c.cpp
@@ -154,6 +154,39 @@ void VerilatedVcd::openNext (bool incFilename) {
     m_wroteBytes = 0;
 }
 
+void VerilatedVcd::makeNameMap() {
+    // Take signal information from each module and build m_namemapp
+    m_namemapp = new NameMap;
+    for (vluint32_t ent = 0; ent< m_callbacks.size(); ent++) {
+	VerilatedVcdCallInfo *cip = m_callbacks[ent];
+	cip->m_code = nextCode();
+	(cip->m_initcb) (this, cip->m_userthis, cip->m_code);
+    }
+
+    // Though not speced, it's illegal to generate a vcd with signals
+    // not under any module - it crashes at least two viewers.
+    // If no scope was specified, prefix everything with a "top"
+    // This comes from user instantiations with no name - IE Vtop("").
+    bool nullScope = false;
+    for (NameMap::iterator it=m_namemapp->begin(); it!=m_namemapp->end(); ++it) {
+	const char* hiername = (*it).first.c_str();
+	if (hiername[0] == '\t') nullScope=true;
+    }
+    if (nullScope) {
+	NameMap* newmapp = new NameMap;
+	for (NameMap::iterator it=m_namemapp->begin(); it!=m_namemapp->end(); ++it) {
+	    const string& hiername = it->first;
+	    const string& decl     = it->second;
+	    string newname = string("top");
+	    if (hiername[0] != '\t') newname += ' ';
+	    newname += hiername;
+	    newmapp->insert(make_pair(newname,decl));
+	}
+	delete m_namemapp; m_namemapp=NULL;
+	m_namemapp = newmapp;
+    }
+}
+
 VerilatedVcd::~VerilatedVcd() {
     close();
     if (m_wrBufp) { delete[] m_wrBufp; m_wrBufp=NULL; }
@@ -314,13 +347,7 @@ void VerilatedVcd::dumpHeader () {
     printStr(doubleToTimescale(m_timeRes).c_str());
     printStr(" $end\n");
 
-    // Take signal information from each module and build m_namemapp
-    m_namemapp = new NameMap;
-    for (vluint32_t ent = 0; ent< m_callbacks.size(); ent++) {
-	VerilatedVcdCallInfo *cip = m_callbacks[ent];
-	cip->m_code = nextCode();
-	(cip->m_initcb) (this, cip->m_userthis, cip->m_code);
-    }
+    makeNameMap();
 
     // Signal header
     assert (m_modDepth==0);
@@ -346,7 +373,7 @@ void VerilatedVcd::dumpHeader () {
 	// Skip common prefix, it must break at a space or tab
 	for (; *np && (*np == *lp); np++, lp++) {}
 	while (np!=hiername && *np && *np!=' ' && *np!='\t') { np--; lp--; }
-	//cout <<"hier "<<hiername<<endl<<"  lp "<<lp<<endl<<"  np "<<np<<endl;
+	//printf("hier %s\n  lp=%s\n  np=%s\n",hiername,lp,np);
 
 	// Any extra spaces in last name are scope ups we need to do
 	bool first = true;
@@ -394,7 +421,7 @@ void VerilatedVcd::module (string name) {
 }
 
 void VerilatedVcd::declare (vluint32_t code, const char* name, const char* wirep,
-			  int arraynum, bool tri, bool bussed, int msb, int lsb) {
+			    int arraynum, bool tri, bool bussed, int msb, int lsb) {
     if (!code) { vl_fatal(__FILE__,__LINE__,"","Internal: internal trace problem, code 0 is illegal"); }
 
     int bits = ((msb>lsb)?(msb-lsb):(lsb-msb))+1;
diff --git a/include/verilated_vcd_c.h b/include/verilated_vcd_c.h
index 60c3aa3a0..2fb77b35e 100644
--- a/include/verilated_vcd_c.h
+++ b/include/verilated_vcd_c.h
@@ -99,6 +99,7 @@ private:
     void closePrev();
     void closeErr();
     void openNext();
+    void makeNameMap();
     void printIndent (int levelchange);
     void printStr (const char* str);
     void printQuad (vluint64_t n);