From eafed88a6ef89341bb5d152290d89693c19c9c03 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sat, 25 Jan 2020 10:19:59 -0500
Subject: [PATCH] Internals: Add assertions. No functional change intended.

---
 src/V3Descope.cpp  | 1 +
 src/V3Graph.h      | 1 +
 src/V3Life.cpp     | 2 +-
 src/V3LinkDot.cpp  | 2 +-
 src/V3Order.cpp    | 1 +
 src/V3Tristate.cpp | 7 +++++--
 6 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/V3Descope.cpp b/src/V3Descope.cpp
index bd80c51f4..5a1635586 100644
--- a/src/V3Descope.cpp
+++ b/src/V3Descope.cpp
@@ -104,6 +104,7 @@ private:
         //
         // V3Combine wouldn't likely be able to combine top-level
         // routines anyway, so there's no harm in keeping these static.
+        UASSERT_OBJ(m_modp, scopep, "Scope not under module");
         if (m_modp->isTop()) relativeRefOk = false;
         //
         // Use absolute refs if this scope is the only instance of the module.
diff --git a/src/V3Graph.h b/src/V3Graph.h
index c16e38626..2af27c93c 100644
--- a/src/V3Graph.h
+++ b/src/V3Graph.h
@@ -104,6 +104,7 @@ public:
     // METHODS
     void clear();  // Empty it of all vertices/edges, as if making a new object
     void clearColors();
+    bool empty() const { return m_vertices.empty(); }
 
     V3GraphVertex* verticesBeginp() const { return m_vertices.begin(); }
 
diff --git a/src/V3Life.cpp b/src/V3Life.cpp
index f575d0526..44d86ab18 100644
--- a/src/V3Life.cpp
+++ b/src/V3Life.cpp
@@ -420,7 +420,7 @@ private:
         }
     }
     virtual void visit(AstCFunc* nodep) VL_OVERRIDE {
-        //UINFO(4,"  CCALL "<<nodep<<endl);
+        //UINFO(4,"  CFUNC "<<nodep<<endl);
         if (!m_tracingCall && !nodep->entryPoint()) return;
         m_tracingCall = false;
         if (nodep->dpiImport() && !nodep->pure()) {
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index f2a5c6dde..5f2d0089e 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -400,7 +400,7 @@ public:
     VSymEnt* getScopeSym(AstScope* nodep) {
         NameScopeSymMap::iterator it = m_nameScopeSymMap.find(nodep->name());
         UASSERT_OBJ(it != m_nameScopeSymMap.end(), nodep,
-                    "Scope never assigned a symbol entry?");
+                    "Scope never assigned a symbol entry '" << nodep->name() << "'");
         return it->second;
     }
     void implicitOkAdd(AstNodeModule* nodep, const string& varname) {
diff --git a/src/V3Order.cpp b/src/V3Order.cpp
index 48474d564..430490054 100644
--- a/src/V3Order.cpp
+++ b/src/V3Order.cpp
@@ -1036,6 +1036,7 @@ private:
     }
     virtual void visit(AstVarScope* nodep) VL_OVERRIDE {
         // Create links to all input signals
+        UASSERT_OBJ(m_modp, nodep, "Scope not under module");
         if (m_modp->isTop() && nodep->varp()->isNonOutput()) {
             OrderVarVertex* varVxp = newVarUserVertex(nodep, WV_STD);
             new OrderEdge(&m_graph, m_inputsVxp, varVxp, WEIGHT_INPUT);
diff --git a/src/V3Tristate.cpp b/src/V3Tristate.cpp
index b349fa296..85cba19b8 100644
--- a/src/V3Tristate.cpp
+++ b/src/V3Tristate.cpp
@@ -136,6 +136,7 @@ public:
     // CONSTRUCTORS
     TristateGraph() { clear(); }
     virtual ~TristateGraph() { clear(); }
+    VL_UNCOPYABLE(TristateGraph);
 
 private:
     // METHODS
@@ -212,6 +213,7 @@ private:
 
 public:
     // METHODS
+    bool empty() const { return m_graph.empty(); }
     void clear() {
         for (V3GraphVertex* itp = m_graph.verticesBeginp(); itp; itp=itp->verticesNextp()) {
             TristateVertex* vvertexp = static_cast<TristateVertex*>(itp);
@@ -1311,7 +1313,8 @@ class TristateVisitor : public TristateBaseVisitor {
         bool origGraphing = m_graphing;
         int origUnique = m_unique;
         VarMap origLhsmap = m_lhsmap;
-        TristateGraph origTgraph = m_tgraph;
+        // Not preserved, needs pointer instead: TristateGraph origTgraph = m_tgraph;
+        UASSERT_OBJ(m_tgraph.empty(), nodep, "Unsupported: NodeModule under NodeModule");
         {
             // Clear state
             m_graphing = false;
@@ -1337,7 +1340,7 @@ class TristateVisitor : public TristateBaseVisitor {
         m_graphing = origGraphing;
         m_unique = origUnique;
         m_lhsmap = origLhsmap;
-        m_tgraph = origTgraph;
+        m_tgraph.clear();  // Recursion not supported
     }
 
     virtual void visit(AstNodeFTask* nodep) VL_OVERRIDE {